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Ghauri MD, Šušnjar S, Guadagno CN, Bhattacharya S, Thomasson B, Swartling J, Gautam R, Andersson-Engels S, Konugolu Venkata Sekar S. Hybrid heterogeneous phantoms for biomedical applications: a demonstration to dosimetry validation. BIOMEDICAL OPTICS EXPRESS 2024; 15:863-874. [PMID: 38404353 PMCID: PMC10890852 DOI: 10.1364/boe.514994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/12/2024] [Accepted: 01/12/2024] [Indexed: 02/27/2024]
Abstract
Phantoms simultaneously mimicking anatomical and optical properties of real tissues can play a pivotal role for improving dosimetry algorithms. The aim of the paper is to design and develop a hybrid phantom model that builds up on the strengths of solid and liquid phantoms for mimicking various anatomical structures for prostate cancer photodynamic therapy (PDT) dosimetry validation. The model comprises of a photosensitizer-embedded gelatin lesion within a liquid Intralipid prostate shape that is surrounded by a solid silicone outer shell. The hybrid phantom was well characterized for optical properties. The final assembled phantom was also evaluated for fluorescence tomographic reconstruction in conjunction with SpectraCure's IDOSE software. The developed model can lead to advancements in dosimetric evaluations. This would improve PDT outlook as a clinical treatment modality and boost phantom based standardization of biophotonic devices globally.
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Affiliation(s)
- M. Daniyal Ghauri
- Tyndall National Institute, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
- Department of Engineering and Food Sciences, University College Cork, College Road, Cork, T12 K8AF, Ireland
| | - Stefan Šušnjar
- SpectraCure AB, Gasverksgatan 1, SE-222 29 Lund, Sweden
- Department of Physics, Lund University, P.O. Box 118, SE-221 00 Lund, Sweden
| | - Claudia Nunzia Guadagno
- BioPixS Ltd – Biophotonics Standards, IPIC, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
| | - Somdatta Bhattacharya
- Tyndall National Institute, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
| | | | | | - Rekha Gautam
- Tyndall National Institute, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
| | - Stefan Andersson-Engels
- Tyndall National Institute, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
- BioPixS Ltd – Biophotonics Standards, IPIC, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
- Department of Physics, University College Cork, College Road, Cork, T12 K8AF, Ireland
| | - Sanathana Konugolu Venkata Sekar
- Tyndall National Institute, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
- BioPixS Ltd – Biophotonics Standards, IPIC, Lee Maltings Complex, Dyke Parade, T12R5CP, Cork, Ireland
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Gautam R, Mac Mahon D, Eager G, Ma H, Guadagno CN, Andersson-Engels S, Konugolu Venkata Sekar S. Fabrication and characterization of multi-biomarker optimized tissue-mimicking phantoms for multi-modal optical spectroscopy. Analyst 2023; 148:4768-4776. [PMID: 37665320 DOI: 10.1039/d3an00680h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Rapid advancement of novel optical spectroscopy and imaging systems relies on the availability of well-characterised and reproducible protocols for phantoms as a standard for the validation of the technique. The tissue-mimicking phantoms are also used to investigate photon transport in biological samples before clinical trials that require well-characterized phantoms with known optical properties (reduced scattering (μ's) and absorption (μa) coefficients). However, at present, there is limited literature available providing well-characterized phantom recipes considering various biomarkers and tested over a wide range of optical properties covering most of the human organs and applicable to multimodal optical spectroscopy. In this study, gelatin-based phantoms were designed to simulate tissue optical properties where India ink and Intralipid were used as absorbing and scattering agents, respectively. Multiple biomarkers were simulated by varying the gelatin concentration to mimic the change in tissue hydration and hydroxyapatite concentration to mimic bone signature. The recipe along with biomarkers were optimized and characterised over a wide range of optical properties (μa from 0.1 to 0.5 cm-1; μ's from 5 to 15 cm-1) relevant to human tissue using a broadband time-domain diffuse optical spectrometer. The data collected showed a linear relationship between the concentration of ink/lipids and μa/μ's values with negligible coupling between μa and μ's values. While being stored in a refrigerator post-fabrication, the μa and μ's did not change significantly (<4% coefficient of variation, 'CV') over three weeks. The reproducibility in three different sets was validated experimentally and found to be strong with a variation of ≤6% CV in μa and ≤9% CV in μ's. From the 3 × 3 data of μa and μ's matrices, one can deduce the recipe for any target absorption or reduced scattering coefficient. The applicability of the phantoms was tested using diffuse reflectance and Raman spectrometers. A use case application was demonstrated for Raman spectroscopy where hydration and hydroxyapatite phantoms were designed to characterize the Raman instrument. The Raman instrument could detect the change in 1% of HA and 5% of hydration. This study presents a first-of-its-kind robust, well-characterized, multi-biomarker phantom recipe for calibration and benchmarking of multimodal spectroscopy devices assisting in their clinical translation.
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Affiliation(s)
- Rekha Gautam
- Biophotonics@Tyndall, IPIC, Tyndall National Institute, T12 R5CP Cork, Ireland.
| | | | - Gráinne Eager
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | - Hui Ma
- Biophotonics@Tyndall, IPIC, Tyndall National Institute, T12 R5CP Cork, Ireland.
| | | | - Stefan Andersson-Engels
- Biophotonics@Tyndall, IPIC, Tyndall National Institute, T12 R5CP Cork, Ireland.
- Department of Physics, University College Cork, T12 K8AF Cork, Ireland
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Sudakou A, Wabnitz H, Liemert A, Wolf M, Liebert A. Two-layered blood-lipid phantom and method to determine absorption and oxygenation employing changes in moments of DTOFs. BIOMEDICAL OPTICS EXPRESS 2023; 14:3506-3531. [PMID: 37497481 PMCID: PMC10368065 DOI: 10.1364/boe.492168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/29/2023] [Accepted: 05/29/2023] [Indexed: 07/28/2023]
Abstract
Near-infrared spectroscopy (NIRS) is an established technique for measuring tissue oxygen saturation (StO2), which is of high clinical value. For tissues that have layered structures, it is challenging but clinically relevant to obtain StO2 of the different layers, e.g. brain and scalp. For this aim, we present a new method of data analysis for time-domain NIRS (TD-NIRS) and a new two-layered blood-lipid phantom. The new analysis method enables accurate determination of even large changes of the absorption coefficient (Δµa) in multiple layers. By adding Δµa to the baseline µa, this method provides absolute µa and hence StO2 in multiple layers. The method utilizes (i) changes in statistical moments of the distributions of times of flight of photons (DTOFs), (ii) an analytical solution of the diffusion equation for an N-layered medium, (iii) and the Levenberg-Marquardt algorithm (LMA) to determine Δµa in multiple layers from the changes in moments. The method is suitable for NIRS tissue oximetry (relying on µa) as well as functional NIRS (fNIRS) applications (relying on Δµa). Experiments were conducted on a new phantom, which enabled us to simulate dynamic StO2 changes in two layers for the first time. Two separate compartments, which mimic superficial and deep layers, hold blood-lipid mixtures that can be deoxygenated (using yeast) and oxygenated (by bubbling oxygen) independently. Simultaneous NIRS measurements can be performed on the two-layered medium (variable superficial layer thickness, L), the deep (homogeneous), and/or the superficial (homogeneous). In two experiments involving ink, we increased the nominal µa in one of two compartments from 0.05 to 0.25 cm-1, L set to 14.5 mm. In three experiments involving blood (L set to 12, 15, or 17 mm), we used a protocol consisting of six deoxygenation cycles. A state-of-the-art multi-wavelength TD-NIRS system measured simultaneously on the two-layered medium, as well as on the deep compartment for a reference. The new method accurately determined µa (and hence StO2) in both compartments. The method is a significant progress in overcoming the contamination from the superficial layer, which is beneficial for NIRS and fNIRS applications, and may improve the determination of StO2 in the brain from measurements on the head. The advanced phantom may assist in the ongoing effort towards more realistic standardized performance tests in NIRS tissue oximetry. Data and MATLAB codes used in this study were made publicly available.
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Affiliation(s)
- Aleh Sudakou
- Nałęcz Institute of Biocybernetics and Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland
| | - Heidrun Wabnitz
- Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
| | - André Liemert
- Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, Germany
| | - Martin Wolf
- Department of Neonatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Adam Liebert
- Nałęcz Institute of Biocybernetics and Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland
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Ko TS, Catennacio E, Shin SS, Stern J, Massey SL, Kilbaugh TJ, Hwang M. Advanced Neuromonitoring Modalities on the Horizon: Detection and Management of Acute Brain Injury in Children. Neurocrit Care 2023; 38:791-811. [PMID: 36949362 PMCID: PMC10241718 DOI: 10.1007/s12028-023-01690-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 01/31/2023] [Indexed: 03/24/2023]
Abstract
Timely detection and monitoring of acute brain injury in children is essential to mitigate causes of injury and prevent secondary insults. Increasing survival in critically ill children has emphasized the importance of neuroprotective management strategies for long-term quality of life. In emergent and critical care settings, traditional neuroimaging modalities, such as computed tomography and magnetic resonance imaging (MRI), remain frontline diagnostic techniques to detect acute brain injury. Although detection of structural and anatomical abnormalities remains crucial, advanced MRI sequences assessing functional alterations in cerebral physiology provide unique diagnostic utility. Head ultrasound has emerged as a portable neuroimaging modality for point-of-care diagnosis via assessments of anatomical and perfusion abnormalities. Application of electroencephalography and near-infrared spectroscopy provides the opportunity for real-time detection and goal-directed management of neurological abnormalities at the bedside. In this review, we describe recent technological advancements in these neurodiagnostic modalities and elaborate on their current and potential utility in the detection and management of acute brain injury.
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Affiliation(s)
- Tiffany S Ko
- Department of Anesthesiology and Critical Care, Children's Hospital of Philadelphia, Philadelphia, USA.
| | - Eva Catennacio
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, USA
| | - Samuel S Shin
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, USA
| | - Joseph Stern
- Department of Radiology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, USA
| | - Shavonne L Massey
- Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, USA
| | - Todd J Kilbaugh
- Department of Anesthesiology and Critical Care, Children's Hospital of Philadelphia, Philadelphia, USA
| | - Misun Hwang
- Department of Radiology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, USA
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Dumlupinar G, Venkata Sekar SK, Guadagno CN, Matias JS, Lanka P, Kho CK, Andersson-Engels S. Solid optical tissue phantom tools based on upconverting nanoparticles for biomedical applications. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:036004. [PMID: 36915372 PMCID: PMC10006686 DOI: 10.1117/1.jbo.28.3.036004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 11/16/2022] [Indexed: 06/18/2023]
Abstract
SIGNIFICANCE Phantoms play a critical role in the development of biophotonics techniques. There is a lack of novel phantom tools in the emerging field of upconverting nanoparticles (UCNPs) for biophotonics application. This work provides a range of UCNP-based phantom tools and a manufacturing recipe to bridge the gap and accelerate the development of UCNP-based biophotonics applications. AIM The study aims to provide a well-characterized UCNP-based solid phantom recipe and set of phantom tools to address a wide range of UCNP-based biophotonics applications. APPROACH A solid phantom recipe based on silicone matrix was developed to manufacture UCNP-based phantoms. A lab built UCNP imaging system was used to characterize upconverted fluorescence emission of phantoms for linearity, homogeneity, and long-term stability. A photon time-of-flight spectroscopy technique was used to characterize the optical properties of the phantoms. RESULTS In total, 24 phantoms classified into 4 types, namely homogeneous, multilayer, inclusion, and base phantoms, were manufactured. The phantoms exhibit linear behavior over the dosage range of UCNPs. The phantoms were found to be stable over a limited observed period of 4 months with a coefficient of variation of < 4 % . The deep tissue imaging case showed that increasing the thickness of tissue reduced the UCNP emission. CONCLUSIONS A first-of-its-kind UCNP-based solid phantom recipe was developed, and four types of UCNP phantom tools to explore biophotonics applications were presented. The UCNP phantoms exhibited a linear behavior with dosage and were stable over time. An example case showed the potential use of the phantom for deep tissue imaging applications. With recent advance in the use of UCNPs for biophotonics, we believe our recipe and tools will play a pivotal role in the growth of the UCNPs for biophotonics applications.
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Affiliation(s)
- Gokhan Dumlupinar
- Tyndall National Institute, Biophotonics@Tyndall, IPIC, Cork, Ireland
- University College Cork, Department of Physics, Cork, Ireland
| | | | | | - Jean S. Matias
- Tyndall National Institute, Biophotonics@Tyndall, IPIC, Cork, Ireland
- University College Cork, Department of Physics, Cork, Ireland
| | - Pranav Lanka
- Tyndall National Institute, Biophotonics@Tyndall, IPIC, Cork, Ireland
| | - Chris K.W. Kho
- Tyndall National Institute, Biophotonics@Tyndall, IPIC, Cork, Ireland
| | - Stefan Andersson-Engels
- Tyndall National Institute, Biophotonics@Tyndall, IPIC, Cork, Ireland
- University College Cork, Department of Physics, Cork, Ireland
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The Use of Supercontinuum Laser Sources in Biomedical Diffuse Optics: Unlocking the Power of Multispectral Imaging. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11104616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Optical techniques based on diffuse optics have been around for decades now and are making their way into the day-to-day medical applications. Even though the physics foundations of these techniques have been known for many years, practical implementation of these technique were hindered by technological limitations, mainly from the light sources and/or detection electronics. In the past 20 years, the developments of supercontinuum laser (SCL) enabled to unlock some of these limitations, enabling the development of system and methodologies relevant for medical use, notably in terms of spectral monitoring. In this review, we focus on the use of SCL in biomedical diffuse optics, from instrumentation and methods developments to their use for medical applications. A total of 95 publications were identified, from 1993 to 2021. We discuss the advantages of the SCL to cover a large spectral bandwidth with a high spectral power and fast switching against the disadvantages of cost, bulkiness, and long warm up times. Finally, we summarize the utility of using such light sources in the development and application of diffuse optics in biomedical sciences and clinical applications.
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Lanka P, Francis KJ, Kruit H, Farina A, Cubeddu R, Sekar SKV, Manohar S, Pifferi A. Optical signatures of radiofrequency ablation in biological tissues. Sci Rep 2021; 11:6579. [PMID: 33753778 PMCID: PMC7985316 DOI: 10.1038/s41598-021-85653-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 03/02/2021] [Indexed: 12/14/2022] Open
Abstract
Accurate monitoring of treatment is crucial in minimally-invasive radiofrequency ablation in oncology and cardiovascular disease. We investigated alterations in optical properties of ex-vivo bovine tissues of the liver, heart, muscle, and brain, undergoing the treatment. Time-domain diffuse optical spectroscopy was used, which enabled us to disentangle and quantify absorption and reduced scattering spectra. In addition to the well-known global (1) decrease in absorption, and (2) increase in reduced scattering, we uncovered new features based on sensitive detection of spectral changes. These absorption spectrum features are: (3) emergence of a peak around 840 nm, (4) redshift of the 760 nm deoxyhemoglobin peak, and (5) blueshift of the 970 nm water peak. Treatment temperatures above 100 °C led to (6) increased absorption at shorter wavelengths, and (7) further decrease in reduced scattering. This optical behavior provides new insights into tissue response to thermal treatment and sets the stage for optical monitoring of radiofrequency ablation.
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Affiliation(s)
- Pranav Lanka
- Department of Physics, Politecnico di Milano, Milan, Italy
| | - Kalloor Joseph Francis
- Multi-Modality Medical Imaging Group, University of Twente, Enschede, The Netherlands.,Biomedical Photonic Imaging Group Technical Medical Centre, University of Twente, Enschede, The Netherlands
| | - Hindrik Kruit
- Multi-Modality Medical Imaging Group, University of Twente, Enschede, The Netherlands
| | - Andrea Farina
- Institute of Photonics and Nanotechnologies, National Research Council, Milan, Italy.
| | | | | | - Srirang Manohar
- Multi-Modality Medical Imaging Group, University of Twente, Enschede, The Netherlands
| | - Antonio Pifferi
- Department of Physics, Politecnico di Milano, Milan, Italy.,Institute of Photonics and Nanotechnologies, National Research Council, Milan, Italy
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