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Nicolucci P, Gambaro G, Araujo Silva KM, Souza Lima I, Baffa O, Pasquarelli A. XMEA: A New Hybrid Diamond Multielectrode Array for the In Situ Assessment of the Radiation Dose Enhancement by Nanoparticles. Sensors (Basel) 2024; 24:2409. [PMID: 38676026 PMCID: PMC11053603 DOI: 10.3390/s24082409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/06/2024] [Accepted: 04/08/2024] [Indexed: 04/28/2024]
Abstract
This work presents a novel multielectrode array (MEA) to quantitatively assess the dose enhancement factor (DEF) produced in a medium by embedded nanoparticles. The MEA has 16 nanocrystalline diamond electrodes (in a cell-culture well), and a single-crystal diamond divided into four quadrants for X-ray dosimetry. DEF was assessed in water solutions with up to a 1000 µg/mL concentration of silver, platinum, and gold nanoparticles. The X-ray detectors showed a linear response to radiation dose (r2 ≥ 0.9999). Overall, platinum and gold nanoparticles produced a dose enhancement in the medium (maximum of 1.9 and 3.1, respectively), while silver nanoparticles produced a shielding effect (maximum of 37%), lowering the dose in the medium. This work shows that the novel MEA can be a useful tool in the quantitative assessment of radiation dose enhancement due to nanoparticles. Together with its suitability for cells' exocytosis studies, it proves to be a highly versatile device for several applications.
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Affiliation(s)
- Patricia Nicolucci
- Department of Physics, Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-901, Brazil; (P.N.); (I.S.L.); (O.B.)
| | - Guilherme Gambaro
- Department of Physics, Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-901, Brazil; (P.N.); (I.S.L.); (O.B.)
| | - Kyssylla Monnyelle Araujo Silva
- Department of Physics, Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-901, Brazil; (P.N.); (I.S.L.); (O.B.)
| | - Iara Souza Lima
- Department of Physics, Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-901, Brazil; (P.N.); (I.S.L.); (O.B.)
| | - Oswaldo Baffa
- Department of Physics, Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-901, Brazil; (P.N.); (I.S.L.); (O.B.)
| | - Alberto Pasquarelli
- Institute of Electron Devices and Circuits, University of Ulm, 89069 Ulm, Germany
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Matsuda RH, Souza VH, Marchetti TC, Soto AM, Kahilakoski OP, Zhdanov A, Malheiro VHE, Laine M, Nyrhinen M, Sinisalo H, Kicic D, Lioumis P, Ilmoniemi RJ, Baffa O. Robotic-electronic platform for autonomous and accurate transcranial magnetic stimulation targeting. Brain Stimul 2024; 17:469-472. [PMID: 38582491 DOI: 10.1016/j.brs.2024.03.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 03/15/2024] [Accepted: 03/31/2024] [Indexed: 04/08/2024] Open
Affiliation(s)
- Renan H Matsuda
- Department of Physics, Faculty of Philosophy Sciences and Letters of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil; Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, 02150, Espoo, Finland.
| | - Victor H Souza
- Department of Physics, Faculty of Philosophy Sciences and Letters of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil; Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, 02150, Espoo, Finland; School of Physiotherapy, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil
| | - Thais C Marchetti
- Department of Physics, Faculty of Philosophy Sciences and Letters of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil
| | - Ana M Soto
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, 02150, Espoo, Finland
| | - Olli-Pekka Kahilakoski
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, 02150, Espoo, Finland
| | - Andrey Zhdanov
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, 02150, Espoo, Finland
| | - Victor H E Malheiro
- Department of Physics, Faculty of Philosophy Sciences and Letters of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil
| | - Mikael Laine
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, 02150, Espoo, Finland
| | - Mikko Nyrhinen
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, 02150, Espoo, Finland
| | - Heikki Sinisalo
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, 02150, Espoo, Finland
| | - Dubravko Kicic
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, 02150, Espoo, Finland
| | - Pantelis Lioumis
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, 02150, Espoo, Finland
| | - Risto J Ilmoniemi
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, 02150, Espoo, Finland
| | - Oswaldo Baffa
- Department of Physics, Faculty of Philosophy Sciences and Letters of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil
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Gutierrez FV, Lima IS, De Falco A, Ereias BM, Baffa O, Diego de Abreu Lima C, Morais Sinimbu LI, de la Presa P, Luz-Lima C, Damasceno Felix Araujo JF. The effect of temperature on the synthesis of magnetite nanoparticles by the coprecipitation method. Heliyon 2024; 10:e25781. [PMID: 38390158 PMCID: PMC10881852 DOI: 10.1016/j.heliyon.2024.e25781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 02/01/2024] [Accepted: 02/01/2024] [Indexed: 02/24/2024] Open
Abstract
Magnetic nanoparticles, such as magnetite (Fe3O4), exhibit superparamagnetic properties below 15 nm at room temperature. They are being explored for medical applications, and the coprecipitation technique is preferred for cost-effective production. This study investigates the impact of synthesis temperature on the nanoparticles' physicochemical characteristics. Two types of magnetic analysis were conducted. Samples T 40, T 50, and T 60 displayed superparamagnetic behavior, as evidenced by the magnetization curves. The experiments verified the development of magnetic nanoparticles with an average diameter of approximately dozens of nanometers, as determined by various measurement methods such as XDR, Raman, and TEM. Raman spectroscopy showed the characteristic bands of the magnetite phase at 319, 364, 499, and 680 cm-1. This was confirmed in the second analysis with the ZFC-FC curves, which showed that the samples' blocking temperatures were below ambient temperature. ZFC-FC curves revealed a similar magnetization of about 30 emu/g when applying a magnetic field of 5 kOe.
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Affiliation(s)
- Frederico Vieira Gutierrez
- Physics Department, Pontifical Catholic University of Rio de Janeiro, Rua Marques de São Vicente, 22451-900, Rio de Janeiro, Brazil
| | - Iara Souza Lima
- Physics Department, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, 14040-91, SP, Brazil
| | - Anna De Falco
- Chemistry Department, Pontifical Catholic University of Rio de Janeiro, Rua Marques de São Vicente, 22451-900, Rio de Janeiro, Brazil
| | - Beatriz Marques Ereias
- Physics Department, Pontifical Catholic University of Rio de Janeiro, Rua Marques de São Vicente, 22451-900, Rio de Janeiro, Brazil
| | - Oswaldo Baffa
- Physics Department, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, 14040-91, SP, Brazil
| | - Caique Diego de Abreu Lima
- Physics Department, Pontifical Catholic University of Rio de Janeiro, Rua Marques de São Vicente, 22451-900, Rio de Janeiro, Brazil
| | - Lanna Isabely Morais Sinimbu
- Physics Department, Pontifical Catholic University of Rio de Janeiro, Rua Marques de São Vicente, 22451-900, Rio de Janeiro, Brazil
| | - Patricia de la Presa
- Institute of Applied Magnetism, UCM-ADIF-CSIC, A6 22,500km, 28230, Las Rozas, Spain
- Material Physics Department, UCM, Ciudad Universitaria, 28040, Madrid, Spain
| | - Cleanio Luz-Lima
- Physics Department, Federal University of Piauí, 64.049-550, Teresina, PI, Brazil
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Lima IS, Silveira MA, Pavoni J, Guidelli JE, Garrido ECS, Baffa O. Assessment of dosimetric sensitivity enhancement of xylenol orange Fricke gel by AuNPs: optical and MR imaging investigation. Phys Med Biol 2023; 68:225011. [PMID: 37852274 DOI: 10.1088/1361-6560/ad04a9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 10/18/2023] [Indexed: 10/20/2023]
Abstract
Metallic nanoparticles, such as gold (Au, Z = 79) and silver (Ag, Z = 47) nanoparticles (AuNPs and AgNPs, respectively), possess strong surface plasmonic resonance (SPR) and high atomic number, which makes them ideal candidates for enhancing dosimeter sensitivity. In this study, we have inserted different mass percentages (from 0 to 0.015 wt%) of AuNPs into a gelatinous Fricke-xylenol-orange (FXO-f) gel matrix and irradiated it with doses ranging from 2 to 32 Gy, using a source of x-ray of low energy with an effective energy of 42 keV. Optical absorption increased significantly; sensitivity gains of up to 50% were achieved for the FXO-f gel matrix containing 0.011 wt% AuNPs. To elucidate the mechanism underlying this increased sensitivity, we also evaluated FXO-f gel matrixes containing AgNPs. AgNPs insertion into the FXO-f gel matrix did not enhance sensitivity, which suggested that the AgNPs plasmonic absorption band and the FXO-f gel matrix absorption band at 441 nm overlapped, to increase absorption even after the gel matrix was irradiated. To visualize the dose distribution, we recorded optical tomography and acquired 3D reconstruction maps. In addition, we analyzed the dose enhancement factor (DEF) by using magnetic resonance images. AuNPs insertion into the FXO-f gel matrix resulted in a DEF gain of 1.37, associated with the photoelectric effect originating from the increased number of free radicals.
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Affiliation(s)
- I S Lima
- Department of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14040-91, Brazil
| | - M A Silveira
- Department of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14040-91, Brazil
| | - J Pavoni
- Department of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14040-91, Brazil
| | - J E Guidelli
- Department of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14040-91, Brazil
| | - E C S Garrido
- Department of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14040-91, Brazil
| | - O Baffa
- Department of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14040-91, Brazil
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Matsuda RH, Souza VH, Kirsten PN, Ilmoniemi RJ, Baffa O. MarLe: Markerless estimation of head pose for navigated transcranial magnetic stimulation. Phys Eng Sci Med 2023; 46:887-896. [PMID: 37166586 DOI: 10.1007/s13246-023-01263-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 04/16/2023] [Indexed: 05/12/2023]
Abstract
Navigated transcranial magnetic stimulation (nTMS) is a valuable tool for non-invasive brain stimulation. Currently, nTMS requires fixing of markers on the patient's head. Head marker displacements lead to changes in coil placement and brain stimulation inaccuracy. A markerless neuronavigation method is needed to increase the reliability of nTMS and simplify the nTMS protocol. In this study, we introduce and release MarLe, a Python markerless head tracker neuronavigation software for TMS. This novel software uses computer-vision techniques combined with low-cost cameras to estimate the head pose for neuronavigation. A coregistration algorithm, based on a closed-form solution, was designed to track the patient's head and the TMS coil referenced to the individual's brain image. We show that MarLe can estimate head pose based on real-time video processing. An intuitive pipeline was developed to connect the MarLe and nTMS neuronavigation software. MarLe achieved acceptable accuracy and stability in a mockup nTMS experiment. MarLe allows real-time tracking of the patient's head without any markers. The combination of face detection and a coregistration algorithm can overcome nTMS head marker displacement concerns. MarLe can improve reliability, simplify, and reduce the protocol time of brain intervention techniques such as nTMS.
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Affiliation(s)
- Renan H Matsuda
- Department of Physics, Faculty of Philosophy Sciences and Letters of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, Ribeirão Preto, 3900, 14040-901, SP, Brazil.
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, Espoo, 02150, Finland.
| | - Victor H Souza
- Department of Physics, Faculty of Philosophy Sciences and Letters of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, Ribeirão Preto, 3900, 14040-901, SP, Brazil
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, Espoo, 02150, Finland
- School of Physiotherapy, Federal University of Juiz de Fora, Juiz de Fora - MG, Cascatinha, Brazil
| | - Petrus N Kirsten
- Department of Physics, Faculty of Philosophy Sciences and Letters of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, Ribeirão Preto, 3900, 14040-901, SP, Brazil
| | - Risto J Ilmoniemi
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Rakentajanaukio 2, Espoo, 02150, Finland
| | - Oswaldo Baffa
- Department of Physics, Faculty of Philosophy Sciences and Letters of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, Ribeirão Preto, 3900, 14040-901, SP, Brazil
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Tardelli GP, Phan T, Strasburger J, Baffa O, Wakai R. Ferrite Shield to Enhance the Performance of Optically Pumped Magnetometers for Fetal Magnetocardiography. J Clin Med 2023; 12:jcm12093078. [PMID: 37176519 PMCID: PMC10179327 DOI: 10.3390/jcm12093078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/08/2023] [Accepted: 04/21/2023] [Indexed: 05/15/2023] Open
Abstract
Fetal magnetocardiography (fMCG) has proven to be an important tool for the prenatal monitoring of electrical cardiac activity; however, the high cost of superconducting quantum instrumentation (SQUID) poses a limitation for the dissemination of fMCG as a routine clinical technique. Recently, optically pumped magnetometers (OPMs) operating within person-sized, cylindrical shields have made fMCG more practical, but environmental magnetic interference entering through the shield opening substantially degrades the quality of fMCG signals. The goal of this study was to further attenuate these interferences by placing the OPM array within a small ferrite shield. FMCG recordings were made with and without the ferrite shield in ten subjects inside a person-sized, three-layer mu-metal cylindrical shield. Although the fetal signal was slightly attenuated, the environmental interference was reduced substantially, and maternal interference was also diminished. This increased the signal-to-noise ratio significantly and improved the resolution of the smaller waveform components. The performance improvement was highest in the axial direction and compensated for a major weakness of open-ended, person-sized shields. The ferrite shield is especially beneficial for the deployment of triaxial OPM sensors, which require effective shielding in all directions.
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Affiliation(s)
- Gabriela P Tardelli
- Department of Medical Physics, Wisconsin Institute for Medical Research, University of Wisconsin-Madison, Madison, WI 53705, USA
- Department of Physics, School of Philosophy, Science and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-900, SP, Brazil
| | - Tan Phan
- Department of Medical Physics, Wisconsin Institute for Medical Research, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Janette Strasburger
- Division of Cardiology, Department of Pediatrics, Children's Hospital of Wisconsin-Milwaukee, Milwaukee, WI 53226, USA
| | - Oswaldo Baffa
- Department of Physics, School of Philosophy, Science and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-900, SP, Brazil
| | - Ronald Wakai
- Department of Medical Physics, Wisconsin Institute for Medical Research, University of Wisconsin-Madison, Madison, WI 53705, USA
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Arsalani S, Arsalani S, Isikawa M, Guidelli EJ, Mazon EE, Ramos AP, Bakuzis A, Pavan TZ, Baffa O, Carneiro AAO. Hybrid Nanoparticles of Citrate-Coated Manganese Ferrite and Gold Nanorods in Magneto-Optical Imaging and Thermal Therapy. Nanomaterials (Basel) 2023; 13:434. [PMID: 36770395 PMCID: PMC9921964 DOI: 10.3390/nano13030434] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 06/18/2023]
Abstract
The development of nanomaterials has drawn considerable attention in nanomedicine to advance cancer diagnosis and treatment over the last decades. Gold nanorods (GNRs) and magnetic nanoparticles (MNPs) have been known as commonly used nanostructures in biomedical applications due to their attractive optical properties and superparamagnetic (SP) behaviors, respectively. In this study, we proposed a simple combination of plasmonic and SP properties into hybrid NPs of citrate-coated manganese ferrite (Ci-MnFe2O4) and cetyltrimethylammonium bromide-coated GNRs (CTAB-GNRs). In this regard, two different samples were prepared: the first was composed of Ci-MnFe2O4 (0.4 wt%), and the second contained hybrid NPs of Ci-MnFe2O4 (0.4 wt%) and CTAB-GNRs (0.04 wt%). Characterization measurements such as UV-Visible spectroscopy and transmission electron microscopy (TEM) revealed electrostatic interactions caused by the opposing surface charges of hybrid NPs, which resulted in the formation of small nanoclusters. The performance of the two samples was investigated using magneto-motive ultrasound imaging (MMUS). The sample containing Ci-MnFe2O4_CTAB-GNRs demonstrated a displacement nearly two-fold greater than just using Ci-MnFe2O4; therefore, enhancing MMUS image contrast. Furthermore, the preliminary potential of these hybrid NPs was also examined in magnetic hyperthermia (MH) and photoacoustic imaging (PAI) modalities. Lastly, these hybrid NPs demonstrated high stability and an absence of aggregation in water and phosphate buffer solution (PBS) medium. Thus, Ci-MnFe2O4_CTAB-GNRs hybrid NPs can be considered as a potential contrast agent in MMUS and PAI and a heat generator in MH.
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Affiliation(s)
- Saeideh Arsalani
- Department of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto 14040-901, São Paulo, Brazil
| | - Soudabeh Arsalani
- Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, D-10587 Berlin, Germany
| | - Mileni Isikawa
- Department of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto 14040-901, São Paulo, Brazil
| | - Eder J. Guidelli
- Department of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto 14040-901, São Paulo, Brazil
| | - Ernesto E. Mazon
- Department of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto 14040-901, São Paulo, Brazil
| | - Ana Paula Ramos
- Department of Chemistry, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto 14040-901, São Paulo, Brazil
| | - Andris Bakuzis
- Institute of Physics and CNanoMed, Federal University of Goiás, Goiânia 74690-900, São Paulo, Brazil
| | - Theo Z. Pavan
- Department of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto 14040-901, São Paulo, Brazil
| | - Oswaldo Baffa
- Department of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto 14040-901, São Paulo, Brazil
| | - Antonio A. O. Carneiro
- Department of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto 14040-901, São Paulo, Brazil
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Rech AB, Kinoshita A, Donate PM, Nascimento OR, Baffa O. Electron Spin Resonance Dosimetry Studies of Irradiated Sulfite Salts. Molecules 2022; 27:molecules27207047. [PMID: 36296641 PMCID: PMC9611582 DOI: 10.3390/molecules27207047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/14/2022] [Accepted: 10/17/2022] [Indexed: 11/16/2022] Open
Abstract
The study of new materials for radiation dosimetry is important to improve the present state of the art and to help in cases of accidents for retrospective dosimetry. Sulfites are compounds that contain a sulfur ion, widely used in the food industry. Due to the significant application of these compounds, sulfites are interesting candidates for accidental dosimetry, as fortuitous radiation detectors. The presence of the SO3− anion enables its detection by electron spin resonance (ESR) spectroscopy. The Dose–Response behavior, signal stability and other spectral features were investigated for sodium sulfite, sodium bisulfite, sodium metabisulfite and potassium metabisulfite, all in crystalline forms. The ESR spectrum of salts presented stability and proportional response with dose, presenting potential for dosimetry applications.
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Affiliation(s)
- Amanda Burg Rech
- Departamento de Física, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-900, SP, Brazil
| | - Angela Kinoshita
- Pró-Reitoria de Pesquisa e Pós-Graduação, Universidade do Oeste Paulista, Presidente Prudente 19067-175, SP, Brazil
- Correspondence: ; Tel.: +55-18-3229-2079
| | - Paulo Marcos Donate
- Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-900, SP, Brazil
| | - Otaciro Rangel Nascimento
- Departamento de Física Interdisciplinar, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos 13566-590, SP, Brazil
| | - Oswaldo Baffa
- Departamento de Física, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-900, SP, Brazil
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Soares G, Pinto L, Liebl M, Biasotti G, Prospero A, Stoppa E, Bakuzis A, Baffa O, Wiekhorst F, Miranda JRA. Quantitative imaging of magnetic nanoparticles in an unshielded environment using a large AC susceptibility array. J Biol Eng 2022; 16:25. [PMID: 36221096 PMCID: PMC9552418 DOI: 10.1186/s13036-022-00305-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 09/26/2022] [Indexed: 11/29/2022] Open
Abstract
Background Non-invasive magnetic imaging techniques are necessary to assist magnetic nanoparticles in biomedical applications, mainly detecting their distribution inside the body. In Alternating Current Biosusceptometry (ACB), the magnetic nanoparticle's magnetization response under an oscillating magnetic field, which is applied through an excitation coil, is detected with a balanced detection coil system. Results We built a Multi-Channel ACB system (MC-ACB) containing nineteen pick-up coils and obtained 2D quantitative images of magnetic nanoparticle distributions by solving an inverse problem. We reconstructed the magnetic nanoparticles spatial distributions in a field of view of 14 × 14 cm2 with a spatial resolution of 2.0 cm and sensitivity in the milligram scale. A correlation coefficient between quantitative reconstructed and nominal magnetic nanoparticle distributions above 0.6 was found for all measurements. Conclusion Besides other interesting features such as sufficient large field of view dimension for mice and rat studies, portability, and the ability to assess the quantitative magnetic nanoparticles distributions in real-time, the MC-ACB system is a promising tool for quantitative imaging of magnetic nanoparticles distributions in real-time, offering an affordable setup for easy access in clinical or laboratory environments.
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Affiliation(s)
- Guilherme Soares
- Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587, Berlin, Germany. .,Biosciences Institute of Botucatu, São Paulo State University, Botucatu, São Paulo, 18618-689, Brazil.
| | - Leonardo Pinto
- Biosciences Institute of Botucatu, São Paulo State University, Botucatu, São Paulo, 18618-689, Brazil
| | - Maik Liebl
- Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587, Berlin, Germany
| | - Gabriel Biasotti
- Biosciences Institute of Botucatu, São Paulo State University, Botucatu, São Paulo, 18618-689, Brazil
| | - Andre Prospero
- Biosciences Institute of Botucatu, São Paulo State University, Botucatu, São Paulo, 18618-689, Brazil
| | - Erick Stoppa
- Biosciences Institute of Botucatu, São Paulo State University, Botucatu, São Paulo, 18618-689, Brazil
| | - Andris Bakuzis
- Institute of Physics, Federal University of Goiás, Goiânia, 74690-900, Brazil
| | - Oswaldo Baffa
- Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto, Sao Paulo, 14040-900, Brazil
| | - Frank Wiekhorst
- Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587, Berlin, Germany
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da Silveira MA, Pavoni JF, Bruno AC, Arruda GV, Baffa O. Three-Dimensional Dosimetry by Optical-CT and Radiochromic Gel Dosimeter of a Multiple Isocenter Craniospinal Radiation Therapy Procedure. Gels 2022; 8:gels8090582. [PMID: 36135294 PMCID: PMC9498794 DOI: 10.3390/gels8090582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 09/07/2022] [Accepted: 09/07/2022] [Indexed: 11/30/2022] Open
Abstract
Craniospinal irradiation (CSI) is a complex radiation technique employed to treat patients with primitive neuroectodermal tumors such as medulloblastoma or germinative brain tumors with the risk of leptomeningeal spread. In adults, this technique poses a technically challenging planning process because of the complex shape and length of the target volume. Thus, it requires multiple fields and different isocenters to guarantee the primary-tumor dose delivery. Recently, some authors have proposed the use IMRT technique for this planning with the possibility of overlapping adjacent fields. The high-dose delivery complexity demands three-dimensional dosimetry (3DD) to verify this irradiation procedure and motivated this study. We used an optical CT and a radiochromic Fricke-xylenol-orange gel with the addition of formaldehyde (FXO-f) to evaluate the doses delivered at the field junction region of this treatment. We found 96.91% as the mean passing rate using the gamma analysis with 3%/2 mm criteria at the junction region. However, the concentration of fail points in a determined region called attention to this evaluation, indicating the advantages of employing a 3DD technique in complex dose-distribution verifications.
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Affiliation(s)
| | | | - Alexandre Colello Bruno
- Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto–USP, Ribeirão Preto 14015-010, Brazil
| | - Gustavo Viani Arruda
- Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto–USP, Ribeirão Preto 14015-010, Brazil
| | - Oswaldo Baffa
- Departamento de Física, FFCLRP—Universidade de São Paulo, Ribeirão Preto 14040-901, Brazil
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11
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Soares GA, Pereira GM, Romualdo GR, Biasotti GGA, Stoppa EG, Bakuzis AF, Baffa O, Barbisan LF, Miranda JRA. Biodistribution Profile of Magnetic Nanoparticles in Cirrhosis-Associated Hepatocarcinogenesis in Rats by AC Biosusceptometry. Pharmaceutics 2022; 14:pharmaceutics14091907. [PMID: 36145654 PMCID: PMC9504370 DOI: 10.3390/pharmaceutics14091907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/30/2022] [Accepted: 08/31/2022] [Indexed: 11/20/2022] Open
Abstract
Since magnetic nanoparticles (MNPs) have been used as multifunctional probes to diagnose and treat liver diseases in recent years, this study aimed to assess how the condition of cirrhosis-associated hepatocarcinogenesis alters the biodistribution of hepatic MNPs. Using a real-time image acquisition approach, the distribution profile of MNPs after intravenous administration was monitored using an AC biosusceptometry (ACB) assay. We assessed the biodistribution profile based on the ACB images obtained through selected regions of interest (ROIs) in the heart and liver position according to the anatomical references previously selected. The signals obtained allowed for the quantification of pharmacokinetic parameters, indicating that the uptake of hepatic MNPs is compromised during liver cirrhosis, since scar tissue reduces blood flow through the liver and slows its processing function. Since liver monocytes/macrophages remained constant during the cirrhotic stage, the increased intrahepatic vascular resistance associated with impaired hepatic sinusoidal circulation was considered the potential reason for the change in the distribution of MNPs.
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Affiliation(s)
- Guilherme A. Soares
- Department of Biophysics and Pharmacology, Institute of Biosciences, São Paulo State University—UNESP, Botucatu 18618-689, SP, Brazil
- Correspondence:
| | - Gabriele M. Pereira
- Department of Biophysics and Pharmacology, Institute of Biosciences, São Paulo State University—UNESP, Botucatu 18618-689, SP, Brazil
| | - Guilherme R. Romualdo
- Department of Pathology, Botucatu Medical School, São Paulo State University (UNESP), Botucatu 18618-689, SP, Brazil
- Department of Strucutral and Functional Biology, Institute of Biosciences, São Paulo State University—UNESP, Botucatu 18618-689, SP, Brazil
| | - Gabriel G. A. Biasotti
- Department of Biophysics and Pharmacology, Institute of Biosciences, São Paulo State University—UNESP, Botucatu 18618-689, SP, Brazil
| | - Erick G. Stoppa
- Department of Biophysics and Pharmacology, Institute of Biosciences, São Paulo State University—UNESP, Botucatu 18618-689, SP, Brazil
| | - Andris F. Bakuzis
- Institute of Physics, Federal University of Goiás, Goiânia 74690-900, GO, Brazil
| | - Oswaldo Baffa
- Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-900, SP, Brazil
| | - Luis F. Barbisan
- Department of Strucutral and Functional Biology, Institute of Biosciences, São Paulo State University—UNESP, Botucatu 18618-689, SP, Brazil
| | - Jose R. A. Miranda
- Department of Biophysics and Pharmacology, Institute of Biosciences, São Paulo State University—UNESP, Botucatu 18618-689, SP, Brazil
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12
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Bonete JM, Tamashiro JR, Paiva FFGD, Queiroz-Fernandes GMD, Guidelli É, Baffa O, Kinoshita A. Influence of silver nanoparticles on the tissue reaction of polyacrylic acid-based gel. Acta Cir Bras 2022; 37:e370504. [PMID: 35976341 PMCID: PMC9377206 DOI: 10.1590/acb370504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 04/20/2022] [Indexed: 11/22/2022] Open
Abstract
Purpose: To study the influence of silver nanoparticles (AgNP) on tissue reaction when incorporated into a polymeric matrix of polyacrylic acid-based (Carbopol®) gel as a proposal for a new low-cost type of biomaterial that is simple to manufacture for use as an antimicrobial and antioxidative dressing. Methods: In-vivo tests of implantation in the subcutaneous tissue of the back of rats were performed using polyethylene tubes in three situations: empty, only the gel, and gel incorporated with AgNP. Then, the tissue reaction was studied by counting inflammatory cells. Additionally, in-vitro tests of the antioxidative and antimicrobial activity of AgNP were performed. The radical 2,2 diphenyl-1 picrylhydrazyl (DPPH) was used to test the antioxidative activity of AgNP using electron spin resonance. The antimicrobial activity of AgNP was determined by minimum inhibitory concentration against the microorganisms: Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Results: The results indicated that AgNP presents antioxidative activity and was able to inhibit the growth of the microorganisms tested. The addition of AgNP in Carbopol® did not alter the tissue inflammatory response (p>0.05, Kruskal-Wallis’s test). Conclusions: The new biomaterial is promising for future use as a dressing for its beneficial properties for regenerative processes.
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Affiliation(s)
- Jéssica Mariana Bonete
- Graduate student. Centro Universitário Sagrado Coração - Center for Health Sciences - Bauru (SP), Brazil
| | - Jacqueline Roberta Tamashiro
- PhD. Universidade do Oeste Paulista - Postgraduate Program in Environment and Regional Development - Presidente Prudente (SP), Brazil
| | - Fábio Friol Guedes de Paiva
- PhD. Universidade do Oeste Paulista - Postgraduate Program in Environment and Regional Development - Presidente Prudente (SP), Brazil
| | | | - Éder Guidelli
- PhD. Universidade de São Paulo - Faculty of Philosophy, Sciences and Letters of Ribeirão Preto - Ribeirao Preto (SP), Brazil
| | - Oswaldo Baffa
- PhD. Universidade de São Paulo - Faculty of Philosophy, Sciences and Letters of Ribeirão Preto - Ribeirao Preto (SP), Brazil
| | - Angela Kinoshita
- PhD. Universidade do Oeste Paulista - Postgraduate Program in Environment and Regional Development - Presidente Prudente (SP), Brazil
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13
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Baffa O, Nicolucci P, Candeias M, Trompier F, Kinoshita A. Alanine/electron spin resonance dosimetry for environmental qualification of electric equipment in a nuclear power plant. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2021.109934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Rech AB, Kinoshita A, Donate PM, Baffa O. ESR dosimetry with lithium, potassium, and sodium compounds. Appl Radiat Isot 2022; 181:110105. [DOI: 10.1016/j.apradiso.2022.110105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 12/10/2021] [Accepted: 01/07/2022] [Indexed: 11/02/2022]
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Souza VH, Nieminen JO, Tugin S, Koponen LM, Baffa O, Ilmoniemi RJ. TMS with fast and accurate electronic control: Measuring the orientation sensitivity of corticomotor pathways. Brain Stimul 2022; 15:306-315. [PMID: 35038592 DOI: 10.1016/j.brs.2022.01.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 12/30/2021] [Accepted: 01/12/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Transcranial magnetic stimulation (TMS) coils allow only a slow, mechanical adjustment of the stimulating electric field (E-field) orientation in the cerebral tissue. Fast E-field control is needed to synchronize the stimulation with the ongoing brain activity. Also, empirical models that fully describe the relationship between evoked responses and the stimulus orientation and intensity are still missing. OBJECTIVE We aimed to (1) develop a TMS transducer for manipulating the E-field orientation electronically with high accuracy at the neuronally meaningful millisecond-level time scale and (2) devise and validate a physiologically based model describing the orientation selectivity of neuronal excitability. METHODS We designed and manufactured a two-coil TMS transducer. The coil windings were computed with a minimum-energy optimization procedure, and the transducer was controlled with our custom-made electronics. The electronic E-field control was verified with a TMS characterizer. The motor evoked potential amplitude and latency of a hand muscle were mapped in 3° steps of the stimulus orientation in 16 healthy subjects for three stimulation intensities. We fitted a logistic model to the motor response amplitude. RESULTS The two-coil TMS transducer allows one to manipulate the pulse orientation accurately without manual coil movement. The motor response amplitude followed a logistic function of the stimulus orientation; this dependency was strongly affected by the stimulus intensity. CONCLUSION The developed electronic control of the E-field orientation allows exploring new stimulation paradigms and probing neuronal mechanisms. The presented model helps to disentangle the neuronal mechanisms of brain function and guide future non-invasive stimulation protocols.
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Affiliation(s)
- Victor Hugo Souza
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Department of Physics, School of Philosophy, Science and Letters of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil; School of Physiotherapy, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil.
| | - Jaakko O Nieminen
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Sergei Tugin
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Lari M Koponen
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Department of Psychiatry & Behavioral Sciences, Duke University, Durham, NC, USA
| | - Oswaldo Baffa
- Department of Physics, School of Philosophy, Science and Letters of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Risto J Ilmoniemi
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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16
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Matsuda RH, Souza VH, Marchetti TC, Araki VD, Caurin GA, Machado HR, Ilmoniemi RJ, Baffa O. An open-source platform for robotized transcranial magnetic stimulation. Brain Stimul 2021. [DOI: 10.1016/j.brs.2021.10.224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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17
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Lima IS, Guidelli EJ, Baffa O. Dose enhancement factor caused by gold nanoparticles: influence of the dosimetric sensitivity and radiation dose assessed by electron spin resonance dosimetry. Phys Med Biol 2021; 66. [PMID: 34592720 DOI: 10.1088/1361-6560/ac2bb2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 09/30/2021] [Indexed: 11/12/2022]
Abstract
Gold nanoparticles have been extensively used to increase the sensitivity of radiation dosimeters. In this work, nanocomposites of alanine (Ala), 2-methylalanine (2MA), asparagine (Asn) and monosodium glutamate (MSG) containing gold nanoparticles were prepared. The influence of the mass percentage of gold (0.1% up to 3%), absorbed dose (2 Gy-10 kGy) and the intrinsic sensitivity of these materials on the dose enhancement factor (DEF) were investigated. The prepared nanocomposites were characterized by UV-vis absorption spectroscopy and dynamic light scattering technique. Electron spin resonance spectroscopy was employed to assess the dosimetric response. The results revealed that the gold nanoparticles aggregated in the nanocomposites of MSG and Asn but not in the Ala and 2MA samples. Higher DEFs were observed for materials with lower intrinsic sensitivities (Asn and MSG) and for lower doses of radiation, suggesting that the dosimetric response of the nanocomposite dosimeters is governed by the probability of radical recombination. The higher the radiation dose, gold mass percentage and/or intrinsic sensitivity of the dosimetric material, the higher the production of radiation-induced free-radicals, enhancing the probability of radical recombination and resulting in lower DEFs. These results bring new insights about the use of gold nanoparticles to the construction of more sensitive radiation dosimeters.
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Affiliation(s)
- Iara S Lima
- Departamento de Física, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Eder J Guidelli
- Departamento de Física, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Oswaldo Baffa
- Departamento de Física, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
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18
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Rojas DMC, Pavoni JF, Arruda GV, Baffa O. Gel and thermoluminescence dosimetry for dose verifications of a real anatomy simulated prostate conformal radiation treatment in the presence of metallic femoral prosthesis. J Appl Clin Med Phys 2021; 22:278-287. [PMID: 34436819 PMCID: PMC8504585 DOI: 10.1002/acm2.13403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 07/19/2021] [Accepted: 08/30/2021] [Indexed: 12/03/2022] Open
Abstract
This study aims to verify the dose delivery of prostate radiotherapy treatments in an adult pelvic phantom with two metallic hip and femur prosthesis using a four‐field box technique. The prostate planned target volume (PTV) tridimensional (3D) dose distribution was evaluated using gel dosimetry, and thermoluminescent dosimeters (TLD) were used for point‐dose measurements outside it. Both results were compared to the treatment planning system (TPS) dose calculation without using heterogeneity corrections to evaluate the influence of the metal in the dose distribution. MAGIC‐f gel dosimeter (Methacrylic and Ascorbic acid in Gelatin Initiated by Copper with Formaldehyde) associated with magnetic resonance imaging was used. TLD were positioned at several points at the bone metal interface and the sacrum region. The comparison of the gel measured and the TPS calculated dose distributions were done using gamma analysis (3%/3 mm), and a pass rate of 93% was achieved. The TLD dose values at the bone‐metal interface showed variations from the planned dose. However, at the sacrum region, where the beams did not intercept the prosthesis, there was a good agreement between TPS planning and TLD measurements. Our results show how the combination of 3D dosimetry and measurements at specific points in the phantom allowed a comprehensive view of the dose distribution and identified that care must also be paid to regions outside the PTV.
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Affiliation(s)
- Diana M C Rojas
- Department of Physics, Faculty of Philosophy, Sciences, and Letters, University of São Paulo, Ribeirão Preto, Sao Paulo, Brazil
| | - Juliana F Pavoni
- Department of Physics, Faculty of Philosophy, Sciences and Letters, University of São Paulo, Ribeirão Preto, Sao Paulo, Brazil
| | - Gustavo V Arruda
- Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Sao Paulo, Brazil
| | - Oswaldo Baffa
- Department of Physics, Faculty of Philosophy, Sciences and Letters, University of São Paulo, Ribeirão Preto, Sao Paulo, Brazil
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19
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Honorio da Silva E, Baffa O, Elias J, Buls N. Conversion factor for size specific dose estimation of head CT scans based on age, for individuals from 0 up to 18 years old. Phys Med Biol 2021; 66. [PMID: 33571979 DOI: 10.1088/1361-6560/abe559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 02/11/2021] [Indexed: 11/11/2022]
Abstract
Assessing the radiation doses received by patients in computed tomography is still challenging. To overcome this, the American Association of Physicists in Medicine has introduced the concept of the size specific dose estimate (SSDE). However, the calculation of SSDE for head CT scans requires the knowledge of attenuation characteristics of the volume scanned, making its implementation in the daily clinical workflow cumbersome. In this study, we defined conversion coefficients from CTDIvol,16cmto SSDE for head CT scans based solely on the age of the patient. Using the head circumference-for-age from the child growth standards of the World Health Organization (WHO), the effective diameter-for-age was calculated for male and female individuals from 0 to 60 months-old. The effective diameter was converted into a water equivalent diameter-for-age, using a correlation established from the measurements of both quantities in 295 exams of male and female patients, from 0 to 18 years-old. WHO-estimated water equivalent diameter-for-age was validated against the measured water equivalent diameter-for-age. The head circumference-for-age from WHO was extrapolated for male and females individuals up to 18 years-old and their respective water equivalent diameter were estimated. Finally, the SSDE was calculated for all the CT head scans performed in a 9-years period in patients aged from 0 to 18 years old. Typical values of CTDIvol,16cmand DLP were also defined. SSDE varied from 0.80 up to 1.16 of the CTDIvol,16cm, depending on sex and age of the patient. WHO-estimated water equivalent diameter-for-age differed less than 20% from the measured water equivalent diameter-for-age. Typical values of SSDE varied from 28.5 up to 38.9 mGy, while typical values ranged from 30.9 up to 47.6 mGy for the CTDIvol,16cmand from 417.6 up to 861.1 mGy*cm for the DLP. SSDE can be directly calculated for head CT scans once the age of the patient is known.
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Affiliation(s)
| | - Oswaldo Baffa
- Department of Physics, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil
| | - Jorge Elias
- Department of Medical Imaging, Haematology and Clinical Oncology, Ribeirão Preto Medical School, University of Sao Paulo, Brazil
| | - Nico Buls
- Universitair Ziekenhuis, Vrije Universiteit Brussel, Brussels, Belgium
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20
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Lima IS, Guidelli EJ, Baffa O. Potential properties of L-Asparagine for ESR dosimetry applications. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2020.109204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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21
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Arsalani S, Löwa N, Kosch O, Radon P, Baffa O, Wiekhorst F. Magnetic separation of iron oxide nanoparticles to improve their application for magnetic particle imaging. Phys Med Biol 2021; 66:015002. [PMID: 33227720 DOI: 10.1088/1361-6560/abcd19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Magnetic particle imaging (MPI) is a promising medical imaging technique for visualizing the three-dimensional distribution of tracer materials, specifically iron oxide nanoparticles (IONP). The optimization of magnetic nanoparticles (MNP) plays an essential role to improve the image resolution and sensitivity of imaging techniques. OBJECTIVE In this work, the optimization of commercial IONP (EMG 700, Ferrotec) coated with anionic surfactants was carried out using magnetic separation (MS) technique, by a low gradient magnetic separation (LGMS) (<15 T m-1) method, to improve their performance as MPI tracers. APPROACH The magnetophoretical behavior of the samples in different concentrations ranging from 2 to 120 mmol l-1 was investigated over 24 h of separation. The samples were characterized by dynamic light scattering (DLS), AC susceptibility (ACS), magnetic particle spectroscopy (MPS) and they were imaged in a preclinical MPI scanner, before and after MS. MAIN RESULTS DLS results showed that by increasing the concentration from 2 to 120 mmol l-1 the hydrodynamic diameter of MNP decrease from 75 to 47 nm and size distribution decrease from 0.19 to 0.11 after 4 min MS. In addition, the MPS results demonstrated the third harmonic amplitude normalized to the iron amount [Formula: see text] and harmonic ratio [Formula: see text] of signal increase from 8.38 to 10.59 Am2 kg-1 (Fe) and 24.21-26.60, respectively. Furthermore, the MPI images of the samples after separation showed higher MPI resolution. SIGNIFICANCE Therefore, LGMS can be considered as a valuable method to narrow and control the size distribution of MNP for MPI.
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Affiliation(s)
- Soudabeh Arsalani
- Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, D-10587 Berlin, Germany.,Departament of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14040-91, Brazil
| | - Norbert Löwa
- Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, D-10587 Berlin, Germany
| | - Olaf Kosch
- Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, D-10587 Berlin, Germany
| | - Patricia Radon
- Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, D-10587 Berlin, Germany
| | - Oswaldo Baffa
- Departament of Physics, FFCLRP, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14040-91, Brazil
| | - Frank Wiekhorst
- Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, D-10587 Berlin, Germany
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22
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Bonete JÉM, Silva GD, Guidelli ÉJ, GonÇalves PJ, Almeida LM, Baffa O, Kinoshita A. Tissue reaction and anti-biofilm action of new biomaterial composed of latex from Hancornia speciosa Gomes and silver nanoparticles. AN ACAD BRAS CIENC 2020; 92:e20191584. [PMID: 33206788 DOI: 10.1590/0001-3765202020191584] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/06/2020] [Indexed: 02/06/2023] Open
Abstract
In this work, the natural latex extracted from Harconia speciosa was incorporated with silver nanoparticles (AgNP) to compose a functional biomaterial associating the intrinsic angiogenic activity of the latex and the antimicrobial activity of AgNP. Tissue reaction after subcutaneous implantation in dorsum of rats of membranes without AgNP and with 0.05%, 0.4% AgNP was compared at 3, 7 and 25 days. No statistically significant difference in the tissue response of the different biomaterials was observed, indicating that AgNP did not interfere with the inflammatory reaction (p > 0.05) or with the angiogenic activity of latex. Biomembranes were also tested against bacterial biofilm formation by Staphylococcus aureus and the antimicrobial activity of the new biomaterial can be found with bacteria crenation (0.05% AgNP) and no biofilm deposition (0.4% AgNP). Therefore, this biomaterial has interesting properties for the tissue repair process and may be feasible for future applications as dressing.
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Affiliation(s)
- JÉssica M Bonete
- PRPPG, Universidade do Sagrado Coração/USC, Rua Irmã Arminda, 10-50, Bauru, 17011-160 SP, Brazil
| | - Guilherme D Silva
- PRPPG, Universidade do Sagrado Coração/USC, Rua Irmã Arminda, 10-50, Bauru, 17011-160 SP, Brazil
| | - Éder J Guidelli
- Universidade de São Paulo/FFCLRP, Departamento de Física, Av. Bandeirantes, 3900, 14049-900 Ribeirão Preto, SP, Brazil
| | - Pablo J GonÇalves
- Universidade Federal de Goiás/UFG, Instituto Física, Av. Esperança, s/n, Campus Samambaia, 14049-900 Goiânia, GO, Brazil
| | - Luciane M Almeida
- Universidade Estadual de Goiás/UEG, BR-153 3105, Fazenda Barreiro do Meio, Campus Anápolis de Ciências Exatas e Tecnológicas, 75132-400 Anápolis, GO, Brazil
| | - Oswaldo Baffa
- Universidade de São Paulo/FFCLRP, Departamento de Física, Av. Bandeirantes, 3900, 14049-900 Ribeirão Preto, SP, Brazil
| | - Angela Kinoshita
- PPGMADRE, Universidade do Oeste Paulista/UNOESTE, SP-270, Km 572, 19067-175 Presidente Prudente, SP, Brazil.,Curso de Odontologia, Faculdade do Centro Oeste Paulista/FACOP, Rua Luiz Gimenez Mocegose, 72, Distrito Industrial, 17490-000 Piratininga, SP, Brazil
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Arsalani S, Oliveira J, Guidelli EJ, Araujo JF, Wiekhorst F, Baffa O. Synthesis of radioluminescent iron oxide nanoparticles functionalized by anthracene for biomedical applications. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.125105] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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24
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Walg YP, Silveira MA, Eafergan N, Krutman Y, Baffa O, Berman A, Orion I. Characterization of novel polydiacetylene gel dosimeter for radiotherapy. Biomed Phys Eng Express 2020; 6:055017. [PMID: 33444248 DOI: 10.1088/2057-1976/aba638] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Polymer gel dosimeters are instrumental for clinical and research applications in radiotherapy. These dosimeters possess the unique ability to record dose distribution in three dimensions. A Polymer gel dosimeter is composed of organic molecules in a gel matrix, which upon irradiation polymerize to form a conjugated polymer with optical absorbance proportional to the irradiated dose. Other required characteristics of a radiotherapy clinical dosimeter are soft-tissue equivalency, linear dose-response in a range of clinical treatments, and long term stability for the duration of the analysis. The dosimeter presented in this paper is based on diacetylene bearing fatty acid aggregates embedded in a soft-tissue equivalent gel matrix, Phytagel™, which upon irradiation polymerize to form a blue phase polydiacetylene with a strong optical absorption. Initial characterization showed that PDA-gel irradiated with 160 kV x-ray responded linearly to the irradiated dose, and the calculated diffusion coefficient is [Formula: see text] what is very low. It was also found that the percentage depth dose (PDD) curve of the PDA-gel in a 4 × 4 cm2 field, irradiated with 6 MV x-rays, was with good agreement with the literature. PDA-gel has the potential to detect absorbed dose in a range of clinical radiological irradiation regimes.
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Affiliation(s)
- Y Peleg Walg
- Department of Biotechnology Engineering, Ben Gurion University of the Negev, Beer-Sheva 84105, Israel. Department of Nuclear Engineering, Ben Gurion University of the Negev, Beer-Sheva 84105, Israel
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Schellpfeffer MA, Strasburger JF, Baffa O, Strand SA, Lutter W, Phan T, Wakai RT. Dynamics of the use of magnetocardiography in the study of the cardiac conduction system of the chick embryo. Birth Defects Res 2020; 112:1825-1833. [PMID: 32790153 DOI: 10.1002/bdr2.1777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/24/2020] [Accepted: 07/09/2020] [Indexed: 01/02/2023]
Abstract
INTRODUCTION Human fetal magnetocardiography (fMCG) has been done for several decades to evaluate fetal arrhythmias using a superconducting quantum interference device (SQUID) magnetometer, but there is little work in embryonic/fetal animal models. This study uses an optically-pumped magnetometer (OPM) to obtain an fMCG in the chick embryo. METHODS White Leghorn chick embryos were examined from incubation Day #10-19. Different examination chambers were tested to optimize embryonic thermal stability and magnetic signal acquisition. All examinations were done with magnetic shielding. The OPM sensors were placed next to the egg shell. The embryo's position was localized by transilluminating the intact egg or ultrasound imaging the egg with an open air cell to optimize sensor placement. The raw data for each embryo was postprocessed to obtain a fMCG composite waveform. RESULTS fMCG's were obtained in embryos from Day #12 to 19. The best success with intact eggs was obtained using five sensors; one at the bottom and four around the lower perimeter of the egg at 90° intervals with the egg oriented vertically and the air cell up. Using ultrasound imaging with the air cell open only two sensors were necessary, one at the bottom and one laterally next to the embryo. fMCGs were analyzed for heart rate and rhythm, each portion of the PQRST waveform, and the PR interval, QRS complex, RR interval, and QT interval. CONCLUSIONS This study validates the chick embryo as an animal model to study in a longitudinal and noninvasive fashion the fetal cardiac conduction system by using OPM magnetocardiography.
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Affiliation(s)
- Michael A Schellpfeffer
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Janette F Strasburger
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | | | - Sarah A Strand
- University of Wisconsin-Madison, Madison, Wisconsin, USA.,University of Iowa Iowa City, Iowa City, Iowa, USA
| | - William Lutter
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Tan Phan
- University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Ronald T Wakai
- University of Wisconsin-Madison, Madison, Wisconsin, USA
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Arsalani S, Arsalani S, Hadadian Y, Sampaio DRT, Baffa O, Pavan TZ, Carneiro AAO. The effect of magnetization of natural rubber latex-coated magnetite nanoparticles on shear wave dispersion magneto-motive ultrasound. ACTA ACUST UNITED AC 2019; 64:215019. [DOI: 10.1088/1361-6560/ab4693] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Strand S, Lutter W, Strasburger JF, Shah V, Baffa O, Wakai RT. Low-Cost Fetal Magnetocardiography: A Comparison of Superconducting Quantum Interference Device and Optically Pumped Magnetometers. J Am Heart Assoc 2019; 8:e013436. [PMID: 31394997 PMCID: PMC6759914 DOI: 10.1161/jaha.119.013436] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Fetal magnetocardiography (fMCG) is a highly effective technique for evaluation of fetuses with life-threatening arrhythmia, but its dissemination has been constrained by the high cost and complexity of Superconducting Quantum Interference Device (SQUID) instrumentation. Optically pumped magnetometers (OPMs) are a promising new technology that can replace SQUIDs for many applications. This study compares the performance of an fMCG system, utilizing OPMs operating in a person-sized magnetic shield, to that of a conventional fMCG system, utilizing SQUID magnetometers operating in a magnetically shielded room. Methods and Results fMCG recordings were made in 24 subjects using the SQUID system with the mother lying supine in a magnetically shielded room and the OPM system with the mother lying prone in a person-sized, cylindrical shield. Signal-to-noise ratios of the OPM and SQUID recordings were not statistically different and were adequate for diagnostic purposes with both technologies. Although the environmental noise was higher using the small open-ended shield, this was offset by the higher signal amplitude achieved with prone positioning, which reduced the distance between the fetus and sensors and improved patient comfort. In several subjects, fMCG provided a differential diagnosis that was more precise and/or definitive than was possible with echocardiography alone. Conclusions The OPM-based system was portable, improved patient comfort, and performed as well as the SQUID-based system at a small fraction of the cost. Electrophysiological assessment of fetal rhythm is now practical and will have a major impact on management of fetuses with long QT syndrome and other life-threatening arrhythmias.
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Affiliation(s)
- Sarah Strand
- Department of Medical Physics University of Wisconsin Madison WI
| | - William Lutter
- Department of Medical Physics University of Wisconsin Madison WI
| | - Janette F Strasburger
- Division of Cardiology Department of Pediatrics Children's Hospital of Wisconsin- Milwaukee Milwaukee WI
| | | | - Oswaldo Baffa
- Department of Physics FFCLRP Ribeirao Preto, University of Sao Paulo Brazil
| | - Ronald T Wakai
- Department of Medical Physics University of Wisconsin Madison WI
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Zacharias LR, Peres ASC, Souza VH, Conforto AB, Baffa O. Method to assess the mismatch between the measured and nominal parameters of transcranial magnetic stimulation devices. J Neurosci Methods 2019; 322:83-87. [PMID: 31014951 DOI: 10.1016/j.jneumeth.2019.03.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 03/30/2019] [Accepted: 03/31/2019] [Indexed: 01/25/2023]
Abstract
BACKGROUND Small variations in TMS parameters, such as pulse frequency and amplitude may elicit distinct neurophysiological responses. Assessing the mismatch between nominal and experimental parameters of TMS stimulators is essential for safe application and comparisons of results across studies. NEW METHOD A search coil was used to assess exactness and precision errors of amplitude and timing parameters such as interstimulus interval, the period of pulse repetition, and intertrain interval of TMS devices. The method was validated using simulated pulses and applied to six commercial stimulators in single-pulse (spTMS), paired-pulse (ppTMS), and repetitive (rTMS) protocols, working at several combinations of intensities and frequencies. RESULTS In a simulated signal, the maximum exactness error was 1.7% for spTMS and the maximum precision error 1.9% for ppTMS. Three out of six TMS commercial devices showed exactness and precision errors in spTMS amplitude higher than 5%. Moreover, two devices showed amplitude exactness errors higher than 5% in rTMS with parameters suggested by the manufactures. COMPARISON WITH EXISTING METHODS Currently available tools allow characterization of induced electric field intensity and focality, and pulse waveforms of a single TMS pulse. Our method assesses the mismatch between nominal and experimental values in spTMS, ppTMS and rTMS protocols through the exactness and precision errors of amplitude and timing parameters. CONCLUSION This study highlights the importance of evaluating the physical characteristics of TMS devices and protocols, and provides a method for on-site quality assessment of multiple stimulation protocols in clinical and research environments.
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Affiliation(s)
- Leonardo Rakauskas Zacharias
- Departamento de Física, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil; Departamento de Neurociências e Ciências do Comportamento, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
| | - André Salles Cunha Peres
- Departamento de Física, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil; Instituto Internacional de Neurociências Edmond e Lily Safra, Instituto Santos Dumont, Macaíba, RN, Brazil; Instituto do Cérebro, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Victor Hugo Souza
- Departamento de Física, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Adriana Bastos Conforto
- Divisão de Clínica Neurológica, Hospital das Clínicas, Universidade de São Paulo, SP, Brazil; Instituto Israelita de Ensino e Pesquisa, Hospital Israelita Albert Einstein, São Paulo, SP, Brazil
| | - Oswaldo Baffa
- Departamento de Física, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
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Souza VH, Vieira TM, Peres ASC, Garcia MAC, Vargas CD, Baffa O. Effect of TMS coil orientation on the spatial distribution of motor evoked potentials in an intrinsic hand muscle. ACTA ACUST UNITED AC 2019; 63:635-645. [PMID: 28796636 DOI: 10.1515/bmt-2016-0240] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 07/03/2017] [Indexed: 11/15/2022]
Abstract
Previous reports on the relationship between coil orientation and amplitude of motor evoked potential (MEP) in transcranial magnetic stimulation (TMS) did not consider the effect of electrode arrangement. Here we explore this open issue by investigating whether TMS coil orientation affects the amplitude distribution of MEPs recorded from the abductor pollicis brevis (APB) muscle with a bi-dimensional grid of 61 electrodes. Moreover, we test whether conventional mono- and bipolar montages provide representative MEPs compared to those from the grid of electrodes. Our results show that MEPs with the greatest amplitudes were elicited for 45° and 90° coil orientations, i.e. perpendicular to the central sulcus, for all electrode montages. Stimulation with the coil oriented at 135° and 315°, i.e. parallel to the central sulcus, elicited the smallest MEP amplitudes. Additionally, changes in coil orientation did not affect the spatial distribution of MEPs over the muscle extent. It has been shown that conventional electrodes with detection volume encompassing the APB belly may detect representative MEPs for optimal coil orientations. In turn, non-optimal orientations were identified only with the grid of electrodes. High-density electromyography may therefore provide new insights into the effect of coil orientation on MEPs from the APB muscle.
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Affiliation(s)
- Victor Hugo Souza
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP), Universidade de São Paulo (USP), Av. Bandeirantes, 3900, 14040-901 Ribeirão Preto-SP, Brazil, Phone: +55 16 33153778, Fax: +55 16 33154887
| | - Taian Martins Vieira
- Departamento de Arte Corporal, Escola de Educação Física e Desportos, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 540, 21941-599 Rio de Janeiro, RJ, Brazil
- Laboratorio di Ingegneria del Sistema Neuromuscolare, Dipartimento di Elettronica e Telecomunicazioni, Politecnico di Torino, Via Cavalli 22/H, 10138 Turin, Italy
| | - André Salles Cunha Peres
- Instituto Internacional de Neurociência de Natal Edmond e Lily Safra, Instituto Santos Dumont, Rodovia RN 160 Km 03, 3003, 59280-000 Macaíba-RN, Brazil
| | - Marco Antonio Cavalcanti Garcia
- Departamento de Biociências e Atividades Físicas, Escola de Educação Física e Desportos, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 540, 21941-599 Rio de Janeiro-RJ, Brazil
| | - Claudia Domingues Vargas
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, 21941-902 Rio de Janeiro-RJ, Brazil
| | - Oswaldo Baffa
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901 Ribeirão Preto, SP, Brazil
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Souza V, Matsuda R, Peres A, Amorim P, Moraes T, Silva J, Baffa O. InVesalius Navigator, a free and open-source software for navigated transcranial magnetic stimulation. Brain Stimul 2019. [DOI: 10.1016/j.brs.2018.12.894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Guidelli EJ, Lima IS, Baffa O. Monosodium glutamate for accidental, retrospective, and medical dosimetry using electron spin resonance. Radiat Environ Biophys 2018; 57:349-356. [PMID: 30242477 DOI: 10.1007/s00411-018-0756-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/14/2018] [Indexed: 06/08/2023]
Abstract
The risk of a radiation episode has increased in the last years due to several reasons. In case of a nuclear incident, as with the use of an improvised nuclear device, determination of the radiation doses received by the victims is of utmost importance to define the appropriate medical treatment or to monitor the late effects of radiation. Dose assessment in case of accidents can be performed using commonplace materials found in the accident area. In this paper, the dosimetric properties of monosodium glutamate are investigated by electron spin resonance spectroscopy (ESR), for retrospective and accidental dosimetry. The spectroscopic parameters were optimized to achieve higher signal intensity and better signal-to-noise ratio. As a result, the lowest detectable dose was 0.1 Gy, and monosodium glutamate showed a linear dose-response curve for doses ranging from 0.1 Gy to 10 kGy. The dosimetric signal was monitored from minutes right after irradiation, until 1 year. No changes in the signal intensity were observed over this period, meaning that doses could be assessed immediately after radiation exposure and can still be reconstructed long after the accident. This property also implies that late effects due to victim's radiation exposure could be better monitored and understood. ESR signal intensity for samples irradiated with a photon energy below 100 keV was decreased by only 27% and no dose-rate dependence was noticed. Therefore, the ability to measure doses as low as 0.1 Gy, the high stability of the dosimetric signal, as well as independence on dose rate, tissue equivalence, low-cost, and wide commercial availability make monosodium glutamate a very good dosimetric material not only for retrospective and accidental but also for medical dosimetry.
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Affiliation(s)
- Eder J Guidelli
- Departamento de Física, Universidade de São Paulo, Ribeirão Prêto, SP, Brazil.
| | - Iara S Lima
- Departamento de Física, Universidade de São Paulo, Ribeirão Prêto, SP, Brazil
| | - Oswaldo Baffa
- Departamento de Física, Universidade de São Paulo, Ribeirão Prêto, SP, Brazil
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Souza VH, Matsuda RH, Peres ASC, Amorim PHJ, Moraes TF, Silva JVL, Baffa O. Development and characterization of the InVesalius Navigator software for navigated transcranial magnetic stimulation. J Neurosci Methods 2018; 309:109-120. [PMID: 30149047 DOI: 10.1016/j.jneumeth.2018.08.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Revised: 08/07/2018] [Accepted: 08/20/2018] [Indexed: 11/25/2022]
Abstract
BACKGROUND Neuronavigation provides visual guidance of an instrument during procedures of neurological interventions, and has been shown to be a valuable tool for accurately positioning transcranial magnetic stimulation (TMS) coils relative to an individual's anatomy. Despite the importance of neuronavigation, its high cost, low portability, and low availability of magnetic resonance imaging facilities limit its insertion in research and clinical environments. NEW METHOD We have developed and validated the InVesalius Navigator as the first free, open-source software for image-guided navigated TMS, compatible with multiple tracking devices. A point-based, co-registration algorithm and a guiding interface were designed for tracking any instrument (e.g. TMS coils) relative to an individual's anatomy. RESULTS Localization, precision errors, and repeatability were measured for two tracking devices during navigation in a phantom and in a simulated TMS study. Errors were measured in two commercial navigated TMS systems for comparison. Localization error was about 1.5 mm, and repeatability was about 1 mm for translation and 1° for rotation angles, both within limits established in the literature. COMPARISON WITH EXISTING METHODS Existing TMS neuronavigation software programs are not compatible with multiple tracking devices, and do not provide an easy to implement platform for custom tools. Moreover, commercial alternatives are expensive with limited portability. CONCLUSIONS InVesalius Navigator might contribute to improving spatial accuracy and the reliability of techniques for brain interventions by means of an intuitive graphical interface. Furthermore, the software can be easily integrated into existing neuroimaging tools, and customized for novel applications such as multi-locus and/or controllable-pulse TMS.
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Affiliation(s)
- Victor Hugo Souza
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil.
| | - Renan H Matsuda
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil.
| | - André S C Peres
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil; Instituto Internacional de Neurociência de Natal Edmond e Lily Safra, Instituto Santos Dumont, Rodovia RN 160 Km 03, 3003, 59280-000, Macaíba, RN, Brazil.
| | - Paulo Henrique J Amorim
- Núcleo de Tecnologias Tridimensionais, Centro de Tecnologia da Informação Renato Archer, Rodovia Dom Pedro I Km 143, 13069-901, Campinas, SP, Brazil.
| | - Thiago F Moraes
- Núcleo de Tecnologias Tridimensionais, Centro de Tecnologia da Informação Renato Archer, Rodovia Dom Pedro I Km 143, 13069-901, Campinas, SP, Brazil.
| | - Jorge Vicente L Silva
- Núcleo de Tecnologias Tridimensionais, Centro de Tecnologia da Informação Renato Archer, Rodovia Dom Pedro I Km 143, 13069-901, Campinas, SP, Brazil.
| | - Oswaldo Baffa
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brazil.
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Peres ASC, Souza VH, Catunda JMY, Mazzeto-Betti KC, Santos-Pontelli TEG, Vargas CD, Baffa O, de Araújo DB, Pontes-Neto OM, Leite JP, Garcia MAC. Can somatosensory electrical stimulation relieve spasticity in post-stroke patients? A TMS pilot study. BIOMED ENG-BIOMED TE 2018; 63:501-506. [PMID: 28475487 DOI: 10.1515/bmt-2016-0162] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 03/28/2017] [Indexed: 11/15/2022]
Abstract
Evidence suggests that somatosensory electrical stimulation (SES) may decrease the degree of spasticity from neural drives, although there is no agreement between corticospinal modulation and the level of spasticity. Thus, stroke patients and healthy subjects were submitted to SES (3 Hz) for 30' on the impaired and dominant forearms, respectively. Motor evoked potentials induced by single-pulse transcranial magnetic stimulation were collected from two forearm muscles before and after SES. The passive resistance of the wrist joint was measured with an isokinetic system. We found no evidence of an acute carry-over effect of SES on the degree of spasticity.
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Affiliation(s)
- André Salles Cunha Peres
- Laboratório de Neuroimagem Funcional, Instituto do Cérebro - Universidade Federal do Rio Grande do Norte - Av. Nascimento de Castro, 2155 - Morro Branco, Natal, RN 59056-450,Brazil.,Instituto Santos Dumont, Instituto Internacional de Neurociências - Rodovia RN 160, 3001 - Distrito Jundiaí, Macaíba 59280-000, Brazil
| | - Victor Hugo Souza
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto - Universidade de São Paulo - Av. Bandeirantes, 3900 - Monte Alegre, Ribeirão Preto, SP 14040-901,Brazil
| | - João Marcos Yamasaki Catunda
- Programa de Engenharia Biomédica, COPPE - Universidade Federal do Rio de Janeiro - Av. Horácio Macedo 2030, Centro de Tecnologia, Bloco H, Sala 327 - Cidade Universitária - Ilha do Fundão, Rio de Janeiro, RJ 21941-914,Brazil
| | - Kelley Cristine Mazzeto-Betti
- Departamento de Neurologia, Psiquiatria e Psicologia Médica, Faculdade de Medicina de Ribeirão Preto - Universidade de São Paulo - Av. Bandeirantes, 3900 - Monte Alegre, Ribeirão Preto, SP 14048-900,Brazil
| | - Taiza Elaine Grespan Santos-Pontelli
- Departamento de Neurociências e Ciências do Comportamento, Faculdade de Medicina de Ribeirão Preto - Universidade de São Paulo - Av. Bandeirantes, 3900 - Monte Alegre, Ribeirão Preto, SP 14048-900,Brazil
| | - Claudia Domingues Vargas
- Laboratório de Neurobiologia II, Instituto de Biofísica Carlos Chagas Filho - Universidade Federal do Rio de Janeiro - Av. Carlos Chagas Filho, 373 - Cidade Universitária - Ilha do Fundão, Rio de Janeiro, RJ 21941-902,Brazil
| | - Oswaldo Baffa
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto - Universidade de São Paulo - Av. Bandeirantes, 3900 - Monte Alegre, Ribeirão Preto, SP 14040-901,Brazil
| | - Draulio Barros de Araújo
- Laboratório de Neuroimagem Funcional, Instituto do Cérebro - Universidade Federal do Rio Grande do Norte - Av. Nascimento de Castro, 2155 - Morro Branco, Natal, RN 59056-450,Brazil
| | - Octávio Marques Pontes-Neto
- Departamento de Neurologia, Psiquiatria e Psicologia Médica, Faculdade de Medicina de Ribeirão Preto - Universidade de São Paulo - Av. Bandeirantes, 3900 - Monte Alegre, Ribeirão Preto, SP 14048-900,Brazil
| | - João Pereira Leite
- Departamento de Neurologia, Psiquiatria e Psicologia Médica, Faculdade de Medicina de Ribeirão Preto - Universidade de São Paulo - Av. Bandeirantes, 3900 - Monte Alegre, Ribeirão Preto, SP 14048-900,Brazil
| | - Marco Antonio Cavalcanti Garcia
- Departamento de Biociências e Atividades Físicas, Escola de Educação Física e Desportos - Universidade Federal do Rio de Janeiro - Avenida Carlos Chagas Filho, 540 - Cidade Universitária - Ilha do Fundão, Rio de Janeiro, RJ 21941-599,Brazil, Phone: +55(21)3938-6824,
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Grillo FW, Souza VH, Matsuda RH, Rondinoni C, Pavan TZ, Baffa O, Machado HR, Carneiro AAO. Patient-specific neurosurgical phantom: assessment of visual quality, accuracy, and scaling effects. 3D Print Med 2018; 4:3. [PMID: 29782617 PMCID: PMC5954795 DOI: 10.1186/s41205-018-0025-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 02/26/2018] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Training in medical education depends on the availability of standardized materials that can reliably mimic the human anatomy and physiology. One alternative to using cadavers or animal bodies is to employ phantoms or mimicking devices. Styrene-ethylene/butylene-styrene (SEBS) gels are biologically inert and present tunable properties, including mechanical properties that resemble the soft tissue. Therefore, SEBS is an alternative to develop a patient-specific phantom, that provides real visual and morphological experience during simulation-based neurosurgical training. RESULTS A 3D model was reconstructed and printed based on patient-specific magnetic resonance images. The fused deposition of polyactic acid (PLA) filament and selective laser sintering of polyamid were used for 3D printing. Silicone and SEBS materials were employed to mimic soft tissues. A neuronavigation protocol was performed on the 3D-printed models scaled to three different sizes, 100%, 50%, and 25% of the original dimensions. A neurosurgery team (17 individuals) evaluated the phantom realism as "very good" and "perfect" in 49% and 31% of the cases, respectively, and rated phantom utility as "very good" and "perfect" in 61% and 32% of the cases, respectively. Models in original size (100%) and scaled to 50% provided a quantitative and realistic visual analysis of the patient's cortical anatomy without distortion. However, reduction to one quarter of the original size (25%) hindered visualization of surface details and identification of anatomical landmarks. CONCLUSIONS A patient-specific phantom was developed with anatomically and spatially accurate shapes, that can be used as an alternative for surgical planning. Printed models scaled to sizes that avoided quality loss might save time and reduce medical training costs.
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Affiliation(s)
- Felipe Wilker Grillo
- Department of Physics, Faculty of Philosophy, Science and Letters at Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP 14040-901 Brazil
| | - Victor Hugo Souza
- Department of Physics, Faculty of Philosophy, Science and Letters at Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP 14040-901 Brazil
| | - Renan Hiroshi Matsuda
- Department of Physics, Faculty of Philosophy, Science and Letters at Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP 14040-901 Brazil
| | - Carlo Rondinoni
- Department of Physics, Faculty of Philosophy, Science and Letters at Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP 14040-901 Brazil
| | - Theo Zeferino Pavan
- Department of Physics, Faculty of Philosophy, Science and Letters at Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP 14040-901 Brazil
| | - Oswaldo Baffa
- Department of Physics, Faculty of Philosophy, Science and Letters at Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP 14040-901 Brazil
| | - Helio Rubens Machado
- Department of Surgery and Anatomy, Faculty of Medicine at Ribeirao Preto, University of Sao Paulo, Ribeirão Preto, Brazil
| | - Antonio Adilton Oliveira Carneiro
- Department of Physics, Faculty of Philosophy, Science and Letters at Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP CEP 14040-901 Brazil
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Kinoshita A, Baffa O, Mascarenhas S. Electron spin resonance (ESR) dose measurement in bone of Hiroshima A-bomb victim. PLoS One 2018; 13:e0192444. [PMID: 29408890 PMCID: PMC5800652 DOI: 10.1371/journal.pone.0192444] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 01/11/2018] [Indexed: 12/05/2022] Open
Abstract
Explosion of the bombs in Hiroshima and Nagasaki corresponds to the only historical moment when atomic bombs were used against civilians. This event triggered countless investigations into the effects and dosimetry of ionizing radiation. However, none of the investigations has used the victims’ bones as dosimeter. Here, we assess samples of bones obtained from fatal victims of the explosion by Electron Spin Resonance (ESR). In 1973, one of the authors of the present study (SM) traveled to Japan and conducted a preliminary experiment on the victims’ bone samples. The idea was to use the paramagnetism induced in bone after irradiation to measure the radiation dose. Technological advances involved in the construction of spectrometers, better knowledge of the paramagnetic center, and improvement in signal processing techniques have allowed us to resume the investigation. We obtained a reconstructed dose of 9.46 ± 3.4 Gy from the jawbone, which was compatible with the dose distribution in different locations as measured in non-biological materials such as wall bricks and roof tiles.
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Affiliation(s)
- Angela Kinoshita
- Departmento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
- Pró Reitoria de Pesquisa e Pós-Graduação, Universidade Sagrado Coração, Bauru, São Paulo, Brazil
- * E-mail:
| | - Oswaldo Baffa
- Departmento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Sérgio Mascarenhas
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil
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Souza VH, Baffa O, Garcia MAC. Lateralized asymmetries in distribution of muscular evoked responses: An evidence of specialized motor control over an intrinsic hand muscle. Brain Res 2018; 1684:60-66. [PMID: 29408387 DOI: 10.1016/j.brainres.2018.01.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 01/05/2018] [Accepted: 01/23/2018] [Indexed: 12/14/2022]
Abstract
Lateralized neural control over hand muscles has been associated with anatomical and physiological asymmetries in the central nervous system. Some studies suggested that the dominant cerebral hemisphere exhibit larger cortical representation areas with lower excitability, while others reported higher cortical excitability in dominant side compared to the contralateral, or even could not find any differences. Thus, neurophysiological lateral asymmetries are still controversial. This study aimed to evaluate differences in dominant and non-dominant sides in motor evoked potentials (MEPs) distribution and investigate whether conventional montages and high-density surface electromyography (HD-sEMG) provide reliable measurements of corticospinal excitability. MEPs elicited by transcranial magnetic stimulation (TMS) were recorded from dominant and non-dominant sides of healthy right-handed participants with an electrode grid over the abductor pollicis brevis muscle. MEPs amplitude distribution, amplitude, latency and resting motor threshold (MT) were evaluated. MEPs distribution significantly shifted towards the lateral direction on the dominant side. MT, amplitude, and latency did not reveal any asymmetries in functional cortical excitability. MEPs amplitude and latency were different for conventional montages and HD-sEMG. Our results suggest that laterality asymmetries manifest in both levels of cortical representation and muscle recruitment, possibly leading to a more pronounced abduction movement on dominant hemisphere compared to the non-dominant side in right-handers. Furthermore, the use of HD-sEMG provided additional insights over conventional electrode montages. A better understanding of laterality asymmetries in fine motor control may help to establish specialized treatments in sensory motor disorders patients.
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Affiliation(s)
- Victor Hugo Souza
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo. Av. Bandeirantes, 3900, CEP: 14040-901, Monte Alegre, Ribeirão Preto, SP, Brazil.
| | - Oswaldo Baffa
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo. Av. Bandeirantes, 3900, CEP: 14040-901, Monte Alegre, Ribeirão Preto, SP, Brazil.
| | - Marco A C Garcia
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo. Av. Bandeirantes, 3900, CEP: 14040-901, Monte Alegre, Ribeirão Preto, SP, Brazil; Departamento de Biociências e Atividades Físicas, Escola de Educação Física e Desportos, Universidade Federal do Rio de Janeiro. Av. Carlos Chagas Filho, 540, CEP: 21941-599, Cidade Universitária, Rio de Janeiro, RJ, Brazil; Laboratório de Neurobiologia II, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro. Av. Carlos Chagas Filho, 373, CEP: 21941-902, Cidade Universitária, Rio de Janeiro, RJ, Brazil.
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Pavoni JF, Neves-Junior WFP, da Silveira MA, Haddad CMK, Baffa O. Evaluation of a composite Gel-Alanine phantom on an end-to-end test to treat multiple brain metastases by a single isocenter VMAT technique. Med Phys 2017; 44:4869-4879. [PMID: 28594461 DOI: 10.1002/mp.12400] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 04/28/2017] [Accepted: 04/28/2017] [Indexed: 01/08/2023] Open
Abstract
PURPOSE This work aims to evaluate the application of a cylindrical phantom made of dosimetric gel containing alanine pellets distributed inside the gel volume during an end-to-end test of a single isocenter VMAT for simultaneous treatment of multiple brain metastases. The evaluation is based on the comparison of the results obtained with the composite phantom with the treatment planning system (TPS) dose distribution validated by using the clinical conventional quality control with point and planar dose measurements. METHODS A cylindrical MAGIC-f gel phantom containing alanine dosimeters (composite phantom) was used to design the VMAT plan in the treatment planning system (TPS). The alanine dosimeters were pellets with radius of 2.5 mm and height of 3 mm, and played the role of brain metastasis inside the gel cylinder, which simulated the cerebral tissue. Five of the alanine dosimeters were selected to simulate five lesions; five planning target volumes (PTVs) were created including the dosimeters and irradiated with different doses. Conventional quality assurance (QA) was performed on the TPS plan and on the composite phantom; a phantom containing only gel (Gel 1 phantom) was also irradiated. One day after irradiation, magnetic resonance images were acquired for both phantoms on a 3T scanner. An electron spin resonance spectrometer was used to evaluate alanine doses. Calibration curves were constructed for the alanine and the gel dosimeters. All the gel only measurement was repeated (Gel 2 phantom) in order to confirm the previous gel measurement. RESULTS The VMAT treatment plan was approved by the conventional QA. The doses measured by alanine dosimeters on the composite gel phantom agreed to the TPS on average within 3.3%. The alanine dose for each lesion was used to calibrate the gel dosimeter measurements of the concerned PTV. Both gel dose volume histograms (DVH) achieved for each PTV were in agreement with the expected TPS DVH, except for a small discrepancy observed for the Gel 2 curve of PTV1 and the Gel 1 curve of PTV5. In a 3D gamma analyses performed for each PTV volume independently, comparing both the gels' measurements to the TPS and using 3%/3 mm, 5%/2 mm, and 7%/2 mm, more than 90% of the points were approved for all the PTVs, except for the PTV5 comparison in the Gel 1 measurement and for the PTV2 comparison in the Gel 2 measurement. A 3D gamma analysis was also applied for each PTV independently, to compare both gel measurements in order to evaluate the consistence of repeated gel measurements of the same plan, and more than 94.5% of the points were approved. CONCLUSIONS The composite Gel-Alanine phantom can be used for the end-to-end test of a single isocenter VMAT for simultaneous treatment of multiple brain metastases. The use of the alanine as the lesion cores for the treatment planning provided the precise dose measurements inside each lesion and allowed the conversion of the gel R2 values based on an accurate dose measurement inside the target.
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Affiliation(s)
- Juliana Fernandes Pavoni
- Departamento de Física, FFCLRP, Universidade de São Paulo, Av. Bandeirantes 3900, Monte Alegre, 14040-901, Ribeirão Preto, SP, Brazil
| | | | - Matheus Antonio da Silveira
- Departamento de Física, FFCLRP, Universidade de São Paulo, Av. Bandeirantes 3900, Monte Alegre, 14040-901, Ribeirão Preto, SP, Brazil
| | | | - Oswaldo Baffa
- Departamento de Física, FFCLRP, Universidade de São Paulo, Av. Bandeirantes 3900, Monte Alegre, 14040-901, Ribeirão Preto, SP, Brazil
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Murta LO, Guzo MG, Moraes ER, Baffa O, Wakai RT, Comani S. Segmented independent component analysis for improved separation of fetal cardiac signals from nonstationary fetal magnetocardiograms. ACTA ACUST UNITED AC 2017; 60:235-44. [PMID: 25781658 DOI: 10.1515/bmt-2014-0114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Accepted: 01/27/2015] [Indexed: 11/15/2022]
Abstract
Fetal magnetocardiograms (fMCGs) have been successfully processed with independent component analysis (ICA) to separate the fetal cardiac signals, but ICA effectiveness can be limited by signal nonstationarities due to fetal movements. We propose an ICA-based method to improve the quality of fetal signals separated from fMCG affected by fetal movements. This technique (SegICA) includes a procedure to detect signal nonstationarities, according to which the fMCG recordings are divided in stationary segments that are then processed with ICA. The first and second statistical moments and the signal polarity reversal were used at different threshold levels to detect signal transients. SegICA effectiveness was assessed in two fMCG datasets (with and without fetal movements) by comparing the signal-to-noise ratio (SNR) of the signals extracted with ICA and with SegICA. Results showed that the SNR of fetal signals affected by fetal movements improved with SegICA, whereas the SNR gain was negligible elsewhere. The best measure to detect signal nonstationarities of physiological origin was signal polarity reversal at threshold level 0.9. The first statistical moment also provided good results at threshold level 0.6. SegICA seems a promising method to separate fetal cardiac signals of improved quality from nonstationary fMCG recordings affected by fetal movements.
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Kinoshita A, Mollemberg M, Santana W, G Figueiredo AM, Guidon N, Fátima da Luz MD, Guérin C, Baffa O. ESR dating of Smilodon populator from Toca de Cima dos Pilão, Piauí, Brazil. Appl Radiat Isot 2017; 120:66-70. [DOI: 10.1016/j.apradiso.2016.11.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 11/16/2016] [Accepted: 11/17/2016] [Indexed: 10/20/2022]
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Silveira MA, Pavoni JF, Baffa O. Three-dimensional quality assurance of IMRT prostate plans using gel dosimetry. Phys Med 2017; 34:1-6. [PMID: 28108100 DOI: 10.1016/j.ejmp.2016.12.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 11/29/2016] [Accepted: 12/06/2016] [Indexed: 11/17/2022] Open
Abstract
Intensity modulated radiotherapy (IMRT) is one of the most modern radiation therapy treatment techniques. Although IMRT can deliver high and complex conformational doses to the tumor volume, its implementation requires rigorous quality assurance (QA) procedures that include a dosimetric pre-treatment verification of individual patient planning. This verification usually involves measuring a small volume of absolute dose with an ionization chamber and checking bi-dimensional fluency with an array of detectors. The planning technique has tri-dimensional characteristics, but no tridimensional dosimetry has been established in the clinical routine. One strategy to perform three-dimensional dosimetry is to use polymeric gels associated with magnetic resonance imaging to evaluate dose distribution. Here, we have compared the results of conventional QA procedures involving one- and two-dimensional dosimetry to the results of three-dimensional dosimetry conducted with MAGIC-f gel in 10 cases of prostate cancer IMRT planning. More specifically, we used the gamma index (3%/3mm) to compare the results of three-dimensional dosimetry to the expected dose distributions obtained with the treatment planning system. Except for one IMRT treatment plan, the gel dosimetry results agreed with the conventional quality control and provided an overview of dose distribution in the target volume.
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Affiliation(s)
- M A Silveira
- Departamento de Física, FFCLRP, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901, Monte Alegre, Ribeirão Preto, SP, Brazil
| | - J F Pavoni
- Departamento de Física, FFCLRP, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901, Monte Alegre, Ribeirão Preto, SP, Brazil.
| | - O Baffa
- Departamento de Física, FFCLRP, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901, Monte Alegre, Ribeirão Preto, SP, Brazil
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Kinoshita A, Ghilardi AM, Fernandes MA, Figueiredo AMG, Baffa O. Electron Spin Resonance Dating of Toxodon Tooth from Upper Ribeira Valley, São Paulo, Brazil. Radiat Prot Dosimetry 2016; 172:296-301. [PMID: 27473703 DOI: 10.1093/rpd/ncw195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Indexed: 06/06/2023]
Abstract
Electron spin resonance (ESR) dating was applied to date a sample of fossil tooth found in Ribeira Valley, São Paulo, Brazil. This region is characterized by abundant fossil records of Pleistocene-Holocene South American megafauna belonging to different faunistic moments related to climate changes during the quaternary. As the number of fossils dated is not too large, the dating of materials from this region will provide important information to better understand the events associated with the presence and extinction of these species. The equivalent dose (De) was determined using single exponential fitting resulting in (24 ± 1)Gy. The De was converted to age using ROSY ESR Dating program and the concentration of radioisotopes present in the sample and soil determined through neutron activation analysis. The ages cover the range of 25-34 ka. This information is important to contextualize other findings in the region from different sites and to help obtain better information about the climate changes in this region.
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Affiliation(s)
- Angela Kinoshita
- Universidade do Sagrado Coração (USC), Bauru, São Paulo, Brazil
- Departamento de Física, FFCLRP, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
- Present Address: Rua Irmã Arminda 10-50, Bauru, SP 17.011-160, Brazil
| | | | | | | | - Oswaldo Baffa
- Departamento de Física, FFCLRP, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
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Guidelli EJ, Ramos AP, Baffa O. Unconventional Increase in Non-Radiative Transitions in Plasmon-Enhanced Luminescence: A Distance-Dependent Coupling. Sci Rep 2016; 6:36691. [PMID: 27848977 PMCID: PMC5111102 DOI: 10.1038/srep36691] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 10/10/2016] [Indexed: 11/08/2022] Open
Abstract
We used Optically Stimulated Luminescence (OSL) from X-ray-irradiated sodium chloride nanocrystals to investigate how silver nanoparticle (AgNP) films enhanced luminescence. We controlled the emitter-AgNP distance and used the OSL intensity and decay times to explore the plasmonic interactions underlying the enhanced luminescence. Both intensity and decay times depended on the emitter-AgNP distance, which suggested that a mechanism involving energy transfer from the localized surface plasmons (LSPs) to the trapped electrons took place through a distance-dependent coupling. Compared to other plasmon-enhanced mechanisms, the energy transfer observed here occurred in the opposite bias: LSP relaxation stimulated electron transfer from non-optically active traps to optically active traps, which culminated in enhanced emission. Therefore, a different mechanism of plasmonic coupling converted optically unreachable electrons into useful luminescence information.
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Affiliation(s)
- Eder José Guidelli
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brasil
| | - Ana Paula Ramos
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brasil
| | - Oswaldo Baffa
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brasil
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Kinoshita A, Sullasi HL, Asfora VK, Azevedo RL, Guzzo P, Guidon N, Figueiredo AMG, Khoury H, Pessis AM, Baffa O. Dating of fossil human teeth and shells from Toca do Enoque site at Serra das Confusões National Park, Brazil. AN ACAD BRAS CIENC 2016; 88:847-55. [PMID: 27276381 DOI: 10.1590/0001-3765201620150083] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 07/11/2015] [Indexed: 11/22/2022] Open
Abstract
This work reports the dating of a fossil human tooth and shell found at the archaeological site Toca do Enoque located in Serra das Confusões National Park (Piauí, Brazil). Many prehistoric paintings have been found at this site. An archaeological excavation unearthed three sepulchers with human skeletons and some shells. Two Brazilian laboratories, in Ribeirão Preto (USP) and Recife (UFPE), independently performed Electron Spin Resonance (ESR) measurements to date the tooth and the shell and obtain the equivalent dose received by each sample. The laboratories determined similar ages for the tooth and the shell (~4.8 kyBP). The results agreed with C-14 dating of the shell and other samples (charcoal) collected in the same sepulcher. Therefore, this work provides a valid inter-comparison of results by two independent ESR-dating laboratories and between two dating methods; i.e., C-14 and ESR, showing the validity of ESR dating for this range of ages.
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Affiliation(s)
- Angela Kinoshita
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, FFCLRP/USP, Avenida Bandeirantes, 3900, Vila Monte Alegre, 14040-901 Ribeirão Preto, SP, Brasil, Universidade de São Paulo, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto SP , Brazil.,Universidade do Sagrado Coração/USC, Rua Irmã Arminda, 10-50, Jardim Brasil, 17011-160 Bauru, SP, Brasil, Universidade do Sagrado Coração, Universidade do Sagrado Coração, Bauru SP , Brazil
| | - Henry L Sullasi
- Departamento de Arqueologia, Universidade Federal de Pernambuco/UFPE. Av. da Arquitetura, s/n, Centro de Filosofia e Ciências Humanas, 10º Andar, Cidade Universitária, 50740-550 Recife, PE, Brasil, Universidade Federal de Pernambuco, Departamento de Arqueologia, Universidade Federal de Pernambuco, Recife PE , Brazil.,Fundação Museu do Homem Americano/FUMDHAM, Centro Cultural Sérgio Motta, s/n, Bairro Campestre, 64770-000 São Raimundo Nonato, PI, Brasil, Fundação Museu do Homem Americano, São Raimundo Nonato PI , Brasil
| | - Viviane K Asfora
- Departamento de Energia Nuclear, Universidade Federal de Pernambuco, Av. Prof. Luiz Freire, 1000, Cidade Universitária, 50740-545, Recife, PE, Brasil, Universidade Federal de Pernambuco, Departamento de Energia Nuclear, Universidade Federal de Pernambuco, Recife PE , Brazil
| | - Renata L Azevedo
- Departamento de Energia Nuclear, Universidade Federal de Pernambuco, Av. Prof. Luiz Freire, 1000, Cidade Universitária, 50740-545, Recife, PE, Brasil, Universidade Federal de Pernambuco, Departamento de Energia Nuclear, Universidade Federal de Pernambuco, Recife PE , Brazil
| | - Pedro Guzzo
- Departamento de Engenharia de Minas, Universidade Federal de Pernambuco/UFPE, Avenida Acadêmico Hélio Ramos, s/n, Cidade Universitária, 50740-530 Recife, PE, Brasil, Universidade Federal de Pernambuco, Departamento de Engenharia de Minas, Universidade Federal de Pernambuco, Recife PE , Brazil
| | - Niede Guidon
- Fundação Museu do Homem Americano/FUMDHAM, Centro Cultural Sérgio Motta, s/n, Bairro Campestre, 64770-000 São Raimundo Nonato, PI, Brasil, Fundação Museu do Homem Americano, São Raimundo Nonato PI , Brasil
| | - Ana Maria G Figueiredo
- Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP. Av. Prof. Lineu Prestes, 2242, Cidade Universitária, 05508-000 São Paulo, SP, Brasil, Instituto de Pesquisas Energéticas e Nucleares, Instituto de Pesquisas Energéticas e Nucleares, São Paulo SP , Brazil
| | - Helen Khoury
- Departamento de Energia Nuclear, Universidade Federal de Pernambuco, Av. Prof. Luiz Freire, 1000, Cidade Universitária, 50740-545, Recife, PE, Brasil, Universidade Federal de Pernambuco, Departamento de Energia Nuclear, Universidade Federal de Pernambuco, Recife PE , Brazil
| | - Anne-Marie Pessis
- Departamento de Arqueologia, Universidade Federal de Pernambuco/UFPE. Av. da Arquitetura, s/n, Centro de Filosofia e Ciências Humanas, 10º Andar, Cidade Universitária, 50740-550 Recife, PE, Brasil, Universidade Federal de Pernambuco, Departamento de Arqueologia, Universidade Federal de Pernambuco, Recife PE , Brazil.,Fundação Museu do Homem Americano/FUMDHAM, Centro Cultural Sérgio Motta, s/n, Bairro Campestre, 64770-000 São Raimundo Nonato, PI, Brasil, Fundação Museu do Homem Americano, São Raimundo Nonato PI , Brasil
| | - Oswaldo Baffa
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, FFCLRP/USP, Avenida Bandeirantes, 3900, Vila Monte Alegre, 14040-901 Ribeirão Preto, SP, Brasil, Universidade de São Paulo, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto SP , Brazil
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Oliveira LC, Yukihara EG, Baffa O. MgO:Li,Ce,Sm as a high-sensitivity material for Optically Stimulated Luminescence dosimetry. Sci Rep 2016; 6:24348. [PMID: 27076349 PMCID: PMC4830961 DOI: 10.1038/srep24348] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 03/24/2016] [Indexed: 11/28/2022] Open
Abstract
The goal of this work was to investigate the relevant dosimetric and luminescent properties of MgO:Li3%,Ce0.03%,Sm0.03%, a newly-developed, high sensitivity Optically Stimulated Luminescence (OSL) material of low effective atomic number (Zeff = 10.8) and potential interest for medical and personal dosimetry. We characterized the thermoluminescence (TL), OSL, radioluminescence (RL), and OSL emission spectrum of this new material and carried out a preliminary investigation on the OSL signal stability. MgO:Li,Ce,Sm has a main TL peak at ~180 °C (at a heating rate of 5 °C/s) associated with Ce3+ and Sm3+ emission. The results indicate that the infrared (870 nm) stimulated OSL from MgO:Li,Ce,Sm has suitable properties for dosimetry, including high sensitivity to ionizing radiation (20 times that of Al2O3:C, under the measurement conditions) and wide dynamic range (7 μGy–30 Gy). The OSL associated with Ce3+ emission is correlated with a dominant, practically isolated peak at 180 °C. Fading of ~15% was observed in the first hour, probably due to shallow traps, followed by subsequent fading of 6–7% over the next 35 days. These properties, together with the characteristically fast luminescence from Ce3+, make this material also a strong candidate for 2D OSL dose mapping.
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Affiliation(s)
- Luiz C Oliveira
- Departamento de Física, FFCLRP-Universidade de São Paulo, 14040-901 Ribeirão Preto-SP, Brazil
| | | | - Oswaldo Baffa
- Departamento de Física, FFCLRP-Universidade de São Paulo, 14040-901 Ribeirão Preto-SP, Brazil
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Guidelli EJ, Ramos AP, Baffa O. Enhancing and quenching luminescence with gold nanoparticle films: the influence of substrate on the luminescent properties. Nanotechnology 2016; 27:015503. [PMID: 26606392 DOI: 10.1088/0957-4484/27/1/015503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Gold nanoparticle (AuNP) films were sputtered over glass and aluminum substrates to enhance optically stimulated luminescence (OSL), a luminescent technique employed for radiation detection, from x-ray irradiated NaCl nanocrystals. The AuNP films deposited over glass led to enhanced-OSL emission, whereas the AuNP films deposited on aluminum substrates quenched the OSL emission. The enhanced-OSL intensity is proportional to the optical density of the film's plasmon resonance band at the stimulation wavelength. For the case of the AuNP/aluminum films, the luminescence quenching diminishes, and OSL intensity partially recovers upon increasing the distance between the AuNPs and the aluminum substrates, and between the luminescent nanocrystals and the AuNP films. These results suggest that plasmonic interactions between the emitter nanocrystals, the localized surface plasmons (LSP) of the AuNPs, and the substrate are responsible for the OSL enhancement and quenching. In this sense, the substrate dictates whether LSP relaxation occurs by radiative or non-radiative transisitions, leading to enhanced or quenched OSL, respectively. Therefore, besides showing that AuNP films can enhance and/or tune the sensitivity of luminescent radiation detectors, and demonstrating OSL as a new technique to investigate mechanisms of plasmon-enhanced luminescence, these results bring insights on how substrates strongly modify the optical properties of AuNP films.
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Affiliation(s)
- Eder José Guidelli
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP, Brasil
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Carvalho Rodrigues MA, dos Santos NAG, da Silva Faria MC, Rodrigues JL, Kinoshita A, Baffa O, Antunes LMG, Barbosa F, Gobe GC, dos Santos AC. Carvedilol protects the kidneys of tumor-bearing mice without impairing the biodistribution or the genotoxicity of cisplatin. Chem Biol Interact 2016; 245:59-65. [PMID: 26751708 DOI: 10.1016/j.cbi.2015.12.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 12/23/2015] [Accepted: 12/29/2015] [Indexed: 10/22/2022]
Abstract
Cisplatin (Cisp) is an effective antitumor drug; however, it causes severe nephrotoxicity. Minimization of renal toxicity is essential, but the interference of nephroprotective agents, particularly antioxidants, with the antitumor activity of cisplatin is a general concern. We have recently demonstrated that the anti-hypertensive and antioxidant drug carvedilol (CV) protects against the renal damage and increases the survival of tumor-bearing mice without impairing the tumor reduction by cisplatin. So far, reports on the antioxidant mechanism of CV are controversial and there are no data on the impact of CV on the antitumor mechanisms of cisplatin. Therefore, this study addresses the effect of CV on mechanisms underlying the tumor control by cisplatin. CV did not interfere with the biodistribution or the genotoxicity of cisplatin. We also addressed the antioxidant mechanisms of CV and demonstrated that it does not neutralize free radicals, but is an efficient chelator of ferrous ions that are relevant catalyzers in cisplatin nephrotoxicity. The present data suggest that oxidative damage and genotoxicity play different roles in the toxicity of cisplatin on kidneys and tumors and therefore, some antioxidants might be safe as chemoprotectors. Altogether, our studies provide consistent evidence of the beneficial effect of CV on animals treated with cisplatin and might encourage clinical trials.
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Affiliation(s)
- Maria A Carvalho Rodrigues
- Centro Universitário do Distrito Federal, UDF, SEP/SUL EQ704/904 Conj.A, Brasilia/DF, CEP 70390-045, Brazil
| | - Neife A G dos Santos
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Av. do Café s/n, 14040-903, Ribeirão Preto, SP, Brazil
| | - Marcia C da Silva Faria
- Universidade Federal do Vale do Jequitinhona e Mucuri, UFVJM, Campus do Mucuri, Teófilo Otoni/MG, Rua do Cruzeiro, nº 01 - Jardim, São Paulo, CEP 39803-371, Brazil
| | - Jairo Lisboa Rodrigues
- Universidade Federal do Vale do Jequitinhona e Mucuri, UFVJM, Campus do Mucuri, Teófilo Otoni/MG, Rua do Cruzeiro, nº 01 - Jardim, São Paulo, CEP 39803-371, Brazil
| | - Angela Kinoshita
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto - USP, Avenida do Café s/n, 14040-901, Ribeirão Preto, SP, Brazil
| | - Oswaldo Baffa
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto - USP, Avenida do Café s/n, 14040-901, Ribeirão Preto, SP, Brazil
| | - Lusania M Greggi Antunes
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Av. do Café s/n, 14040-903, Ribeirão Preto, SP, Brazil
| | - Fernando Barbosa
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Av. do Café s/n, 14040-903, Ribeirão Preto, SP, Brazil
| | - Glenda C Gobe
- Centre for Kidney Disease Research, School of Medicine, The University of Queensland at Princess Alexandra Hospital, Brisbane, QLD, 4102, Australia
| | - Antonio Cardozo dos Santos
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Av. do Café s/n, 14040-903, Ribeirão Preto, SP, Brazil.
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Guidelli EJ, Baffa O, Clarke DR. Enhanced UV Emission From Silver/ZnO And Gold/ZnO Core-Shell Nanoparticles: Photoluminescence, Radioluminescence, And Optically Stimulated Luminescence. Sci Rep 2015; 5:14004. [PMID: 26365945 PMCID: PMC5155625 DOI: 10.1038/srep14004] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 08/06/2015] [Indexed: 11/26/2022] Open
Abstract
The optical properties of core-shell nanoparticles consisting of a ZnO shell grown on Ag and Au nanoparticle cores by a solution method have been investigated. Both the ZnO/Ag and ZnO/Au particles exhibit strongly enhanced near-band-edge UV emission from the ZnO when excited at 325 nm. Furthermore, the UV intensity increases with the metal nanoparticle concentration, with 60-fold and 17-fold enhancements for the ZnO/Ag and ZnO/Au, core-shell nanoparticles respectively. Accompanying the increase in UV emission, there is a corresponding decrease in the broad band defect emission with nanoparticle concentration. Nonetheless, the broad band luminescence increases with laser power. The results are consistent with enhanced exciton emission in the ZnO shells due to coupling with surface plasmon resonance of the metal nanoparticles. Luminescence measurements during and after exposure to X-rays also exhibit enhanced UV luminescence. These observations suggest that metal nanoparticles may be suitable for enhancing optical detection of ionizing radiation.
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Affiliation(s)
- E J Guidelli
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138.,Departamento de Física - FFCLRP- Universidade de São Paulo, Brazil
| | - O Baffa
- Departamento de Física - FFCLRP- Universidade de São Paulo, Brazil
| | - D R Clarke
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
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Affiliation(s)
- Marco A C Garcia
- Departamento de Biociências da Atividade Física, Escola de Educação Física e Desportos, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brasil ; Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo Ribeirão Preto, Brasil
| | - Oswaldo Baffa
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo Ribeirão Preto, Brasil
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Bruno AC, Sampaio DRT, Pavan TZ, Baffa O, Carneiro AAO. A hybrid transducer to evaluate stomach emptying by ultrasound and susceptometric measurements: an in vivo feasibility study. IEEE Trans Ultrason Ferroelectr Freq Control 2015; 62:1288-1294. [PMID: 26168175 DOI: 10.1109/tuffc.2014.006950] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Gastric emptying reflects a diversity of important physiological functions. Alternating current biosusceptometry (ACB) is an inexpensive, radiation-free, and minimally invasive method to evaluate gastric emptying, but its response depends on the spatial distribution of the magnetized material and does not provide precise anatomical information. The hybrid transducer, which combines ACB and an ultrasound probe, is an alternative to improve susceptometry measurements, namely the spatial localization of the magnetized source. In this study, initial stomach emptying, in rats, was monitored with the aid of the hybrid transducer. Yogurt mixed with ferrite particles was injected into the rat's stomach. The hybrid transducer was placed on the rat's abdomen during experiments, and the susceptometry signal and magnetomotive ultrasound (MMUS) images were saved and postprocessed. MMUS highlighted the movement of magnetic particles due to magnetic force from ACB excitation coils, and showed the rat's stomach location. In this feasibility study, we monitored the stomach emptying of 4 rats for 20 min. The mean relative ACB signal decayed by 4.6 ± 0.1%, and the mean relative area of MMUS images decreased by 4.5 ± 0.2%, after 20 min postingestion of the magnetic meal due to stomach emptying. In a second experiment, 3-D MMUS images from axial sequences were obtained by spatially translating the hybrid transducer, providing details of the stomach wall, which may enable minimally invasive detection of abnormalities. In conclusion, the MMUS image increased ACB spatial resolution and furnished additional anatomical information.
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Wolfe T, Guidelli EJ, Gómez JA, Baffa O, Nicolucci P. Experimental assessment of gold nanoparticle-mediated dose enhancement in radiation therapy beams using electron spin resonance dosimetry. Phys Med Biol 2015; 60:4465-80. [PMID: 25988912 DOI: 10.1088/0031-9155/60/11/4465] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this work, we aim to experimentally assess increments of dose due to nanoparticle-radiation interactions via electron spin resonance (ESR) dosimetry performed with a biological-equivalent sensitive material.We employed 2-Methyl-Alanine (2MA) in powder form to compose the radiation sensitive medium embedding gold nanoparticles (AuNPs) 5 nm in diameter. Dosimeters manufactured with 0.1% w/w of AuNPs or no nanoparticles were irradiated with clinically utilized 250 kVp orthovoltage or 6 MV linac x-rays in dosimetric conditions. Amplitude peak-to-peak (App) at the central ESR spectral line was used for dosimetry. Dose-response curves were obtained for samples with or without nanoparticles and each energy beam. Dose increments due to nanoparticles were analyzed in terms of absolute dose enhancements (DEs), calculated as App ratios for each dose/beam condition, or relative dose enhancement factors (DEFs) calculated as the slopes of the dose-response curves.Dose enhancements were observed to present an amplified behavior for small doses (between 0.1-0.5 Gy), with this effect being more prominent with the kV beam. For doses between 0.5-5 Gy, dose-independent trends were observed for both beams, stable around (2.1 ± 0.7) and (1.3 ± 0.4) for kV and MV beams, respectively. We found DEFs of (1.62 ± 0.04) or (1.27 ± 0.03) for the same beams. Additionally, we measured no interference between AuNPs and the ESR apparatus, including the excitation microwaves, the magnetic fields and the paramagnetic radicals.2MA was demonstrated to be a feasible paramagnetic radiation-sensitive material for dosimetry in the presence of AuNPs, and ESR dosimetry a powerful experimental method for further verifications of increments in nanoparticle-mediated doses of biological interest. Ultimately, gold nanoparticles can cause significant and detectable dose enhancements in biological-like samples irradiated at both kilo or megavoltage beams.
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Affiliation(s)
- T Wolfe
- Experimental Radiation Oncology Department, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA
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