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Schwarz A, Shemer A, Danan Y, Bar-Shalom R, Avraham H, Zlotnik A, Zalevsky Z. Gamma Radiation Imaging System via Variable and Time-Multiplexed Pinhole Arrays. SENSORS 2020; 20:s20113013. [PMID: 32466401 PMCID: PMC7313691 DOI: 10.3390/s20113013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 11/16/2022]
Abstract
Biomedical planar imaging using gamma radiation is a very important screening tool for medical diagnostics. Since lens imaging is not available in gamma imaging, the current methods use lead collimator or pinhole techniques to perform imaging. However, due to ineffective utilization of the gamma radiation emitted from the patient’s body and the radioactive dose limit in patients, poor image signal to noise ratio (SNR) and long image capturing time are evident. Furthermore, the resolution is related to the pinhole diameter, thus there is a tradeoff between SNR and resolution. Our objectives are to reduce the radioactive dose given to the patient and to preserve or improve SNR, resolution and capturing time while incorporating three-dimensional capabilities in existing gamma imaging systems. The proposed imaging system is based on super-resolved time-multiplexing methods using both variable and moving pinhole arrays. Simulations were performed both in MATLAB and GEANT4, and gamma single photon emission computed tomography (SPECT) experiments were conducted to support theory and simulations. The proposed method is able to reduce the radioactive dose and image capturing time and to improve SNR and resolution. The results and method enhance the gamma imaging capabilities that exist in current systems, while providing three-dimensional data on the object.
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Affiliation(s)
- Ariel Schwarz
- Department of Electrical and Electronics Engineering, Azrieli College of Engineering, Jerusalem 9103501, Israel; (A.S.); (Y.D.)
| | - Amir Shemer
- Department of Electrical and Electronics Engineering, Azrieli College of Engineering, Jerusalem 9103501, Israel; (A.S.); (Y.D.)
- Correspondence:
| | - Yossef Danan
- Department of Electrical and Electronics Engineering, Azrieli College of Engineering, Jerusalem 9103501, Israel; (A.S.); (Y.D.)
| | - Rachel Bar-Shalom
- Shaare Zedek Medical Center, Jerusalem 9103102, Israel; (R.B.-S.); (H.A.)
| | - Hemy Avraham
- Shaare Zedek Medical Center, Jerusalem 9103102, Israel; (R.B.-S.); (H.A.)
| | - Alex Zlotnik
- Faculty of Engineering, Bar-Ilan University, Ramat-Gan 5290002, Israel; (A.Z.); (Z.Z.)
| | - Zeev Zalevsky
- Faculty of Engineering, Bar-Ilan University, Ramat-Gan 5290002, Israel; (A.Z.); (Z.Z.)
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Bergeson SD, Ware MJ, Hawk J. CMOS-coupled NaI scintillation detector for gamma decay measurements. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:033320. [PMID: 32259921 DOI: 10.1063/1.5138208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 03/04/2020] [Indexed: 06/11/2023]
Abstract
We report an all-solid-state gamma-ray scintillation detector comprised of a NaI(Tl) crystal and a scientific-grade CMOS camera. After calibration, this detector exhibits excellent linearity over more than three decades of activity levels ranging from 10 mCi to 400 nCi. Because the detector is not counting pulses, dead-time correction is not required. Compared to systems that use a photomultiplier tube, this detector has similar sensitivity and noise characteristics on short time scales. On longer time scales, we measure drifts of a few percent over several days, which can be accommodated through regular calibration. Using this detector, we observe that when high activity sources are brought into close proximity to the NaI crystal, several minutes are required for the measured signal to achieve a steady state.
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Affiliation(s)
| | | | - Jeremy Hawk
- Utah Valley Regional Medical Center, Provo, Utah 84602, USA
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3
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Mejia J, Miranda ACC, Durante ACR, de Oliveira LR, de Barboza MRFF, Rosell KT, Jardim DP, Campos AH, dos Reis MA, Catanoso MF, Galvis-Alonso OY, Cabral FR. Preclinical molecular imaging: development of instrumentation for translational research with small laboratory animals. EINSTEIN-SAO PAULO 2016; 14:408-414. [PMID: 27759832 PMCID: PMC5234755 DOI: 10.1590/s1679-45082016ao3696] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 06/27/2016] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE: To present the result of upgrading a clinical gamma-camera to be used to obtain in vivo tomographic images of small animal organs, and its application to register cardiac, renal and neurological images. METHODS: An updated version of the miniSPECT upgrading device was built, which is composed of mechanical, electronic and software subsystems. The device was attached to a Discovery VH (General Electric Healthcare) gamma-camera, which was retired from the clinical service and installed at the Centro de Imagem Pré-Clínica of the Hospital Israelita Albert Einstein. The combined system was characterized, determining operational parameters, such as spatial resolution, magnification, maximum acceptable target size, number of projections, and acquisition and reconstruction times. RESULTS: Images were obtained with 0.5mm spatial resolution, with acquisition and reconstruction times between 30 and 45 minutes, using iterative reconstruction with 10 to 20 iterations and 4 projection subsets. The system was validated acquiring in vivo tomographic images of the heart, kidneys and brain of normal animals (mice and adult rats), using the radiopharmaceuticals technetium-labeled hexakis-2-methoxy-isobutyl isonitrile (99mTc-Sestamibi), technetium-labeled dimercaptosuccinic acid (99mTc-DMSA) and technetium-labeled hexamethyl propyleneamine oxime (99mTc-HMPAO). CONCLUSION: This kind of application, which consists in the adaptation for an alternative objective of already existing instrumentation, resulted in a low-cost infrastructure option, allowing to carry out large scale in vivo studies with enhanced quality in several areas, such as neurology, nephrology, cardiology, among others. OBJETIVO: Apresentar o resultado da adaptação de uma gama câmara clínica para uso dedicado na obtenção de imagens tomográficas in vivo de órgãos de pequenos animais de experimentação, e de sua aplicação na obtenção de imagens cardíacas, renais e neurológicas. MÉTODOS: Foi construída uma versão atualizada do dispositivo de adaptação miniSPECT, composto por três subsistemas: mecânico, eletrônico e de software. O dispositivo foi montado em uma câmara Discovery VH da General Electric Healthcare, retirada do serviço clínico e instalada no Centro de Imagem Pré-Clínica do Hospital Israelita Albert Einstein. O sistema combinado foi caracterizado, determinando parâmetros de funcionamento como resolução espacial, magnificação, limites de tamanho dos alvos de estudo, número de projeções, tempo de registro e tempo de reconstrução das imagens tomográficas. RESULTADOS: Foram obtidas imagens com resolução espacial de até 0,5mm, com tempos de registro e reconstrução de 30 a 45 minutos, utilizando reconstrução iterativa com 10 a 20 iterações e 4 subconjuntos de projeções. O sistema foi validado obtendo imagens tomográficas in vivo do coração, dos rins e do cérebro de animais normais (camundongos e ratos adultos), utilizando os radiofármacos hexaquis-2-metoxi-isobutil-isonitrila marcado com 99mTc (Sestamibi-99mTc), ácido dimercaptosuccínico marcado com 99mTc (DMSA-99mTc) e hexametil-propileno-amina-oxima marcada com 99mTc (HMPAO-99mTc). CONCLUSÃO: Este tipo de aplicação, que consiste na adaptação para um objetivo alternativo de instrumentação já existente, constituiu-se em uma opção de infraestrutura de baixo custo, que permite realizar estudos in vivo em larga escala, com qualidade aprimorada, em áreas diversas, como neurologia, nefrologia, cardiologia, entre outras.
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Affiliation(s)
- Jorge Mejia
- Hospital Israelita Albert Einstein, São Paulo, SP, Brazil
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4
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Miller BW, Frost SHL, Frayo SL, Kenoyer AL, Santos E, Jones JC, Green DJ, Hamlin DK, Wilbur DS, Fisher DR, Orozco JJ, Press OW, Pagel JM, Sandmaier BM. Quantitative single-particle digital autoradiography with α-particle emitters for targeted radionuclide therapy using the iQID camera. Med Phys 2016; 42:4094-105. [PMID: 26133610 DOI: 10.1118/1.4921997] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
PURPOSE Alpha-emitting radionuclides exhibit a potential advantage for cancer treatments because they release large amounts of ionizing energy over a few cell diameters (50-80 μm), causing localized, irreparable double-strand DNA breaks that lead to cell death. Radioimmunotherapy (RIT) approaches using monoclonal antibodies labeled with α emitters may thus inactivate targeted cells with minimal radiation damage to surrounding tissues. Tools are needed to visualize and quantify the radioactivity distribution and absorbed doses to targeted and nontargeted cells for accurate dosimetry of all treatment regimens utilizing α particles, including RIT and others (e.g., Ra-223), especially for organs and tumors with heterogeneous radionuclide distributions. The aim of this study was to evaluate and characterize a novel single-particle digital autoradiography imager, the ionizing-radiation quantum imaging detector (iQID) camera, for use in α-RIT experiments. METHODS The iQID camera is a scintillator-based radiation detection system that images and identifies charged-particle and gamma-ray/x-ray emissions spatially and temporally on an event-by-event basis. It employs CCD-CMOS cameras and high-performance computing hardware for real-time imaging and activity quantification of tissue sections, approaching cellular resolutions. In this work, the authors evaluated its characteristics for α-particle imaging, including measurements of intrinsic detector spatial resolutions and background count rates at various detector configurations and quantification of activity distributions. The technique was assessed for quantitative imaging of astatine-211 ((211)At) activity distributions in cryosections of murine and canine tissue samples. RESULTS The highest spatial resolution was measured at ∼20 μm full width at half maximum and the α-particle background was measured at a rate as low as (2.6 ± 0.5) × 10(-4) cpm/cm(2) (40 mm diameter detector area). Simultaneous imaging of multiple tissue sections was performed using a large-area iQID configuration (ø 11.5 cm). Estimation of the (211)At activity distribution was demonstrated at mBq/μg-levels. CONCLUSIONS Single-particle digital autoradiography of α emitters has advantages over traditional film-based autoradiographic techniques that use phosphor screens, in terms of spatial resolution, sensitivity, and activity quantification capability. The system features and characterization results presented in this study show that the iQID is a promising technology for microdosimetry, because it provides necessary information for interpreting alpha-RIT outcomes and for predicting the therapeutic efficacy of cell-targeted approaches using α emitters.
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Affiliation(s)
- Brian W Miller
- Pacific Northwest National Laboratory, Richland, Washington 99354 and College of Optical Sciences, The University of Arizona, Tucson, Arizona 85719
| | - Sofia H L Frost
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Shani L Frayo
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Aimee L Kenoyer
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Erlinda Santos
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Jon C Jones
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Damian J Green
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109 and Department of Medicine, University of Washington, Seattle, Washington 98195
| | - Donald K Hamlin
- Department of Radiation Oncology, University of Washington, Seattle, Washington 98195
| | - D Scott Wilbur
- Department of Radiation Oncology, University of Washington, Seattle, Washington 98195
| | | | - Johnnie J Orozco
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Oliver W Press
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109 and Department of Medicine, University of Washington, Seattle, Washington 98195
| | - John M Pagel
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109 and Department of Medicine, University of Washington, Seattle, Washington 98195
| | - Brenda M Sandmaier
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109 and Department of Medicine, University of Washington, Seattle, Washington 98195
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Jha AK, Barrett HH, Frey EC, Clarkson E, Caucci L, Kupinski MA. Singular value decomposition for photon-processing nuclear imaging systems and applications for reconstruction and computing null functions. Phys Med Biol 2015; 60:7359-85. [PMID: 26350439 DOI: 10.1088/0031-9155/60/18/7359] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Recent advances in technology are enabling a new class of nuclear imaging systems consisting of detectors that use real-time maximum-likelihood (ML) methods to estimate the interaction position, deposited energy, and other attributes of each photon-interaction event and store these attributes in a list format. This class of systems, which we refer to as photon-processing (PP) nuclear imaging systems, can be described by a fundamentally different mathematical imaging operator that allows processing of the continuous-valued photon attributes on a per-photon basis. Unlike conventional photon-counting (PC) systems that bin the data into images, PP systems do not have any binning-related information loss. Mathematically, while PC systems have an infinite-dimensional null space due to dimensionality considerations, PP systems do not necessarily suffer from this issue. Therefore, PP systems have the potential to provide improved performance in comparison to PC systems. To study these advantages, we propose a framework to perform the singular-value decomposition (SVD) of the PP imaging operator. We use this framework to perform the SVD of operators that describe a general two-dimensional (2D) planar linear shift-invariant (LSIV) PP system and a hypothetical continuously rotating 2D single-photon emission computed tomography (SPECT) PP system. We then discuss two applications of the SVD framework. The first application is to decompose the object being imaged by the PP imaging system into measurement and null components. We compare these components to the measurement and null components obtained with PC systems. In the process, we also present a procedure to compute the null functions for a PC system. The second application is designing analytical reconstruction algorithms for PP systems. The proposed analytical approach exploits the fact that PP systems acquire data in a continuous domain to estimate a continuous object function. The approach is parallelizable and implemented for graphics processing units (GPUs). Further, this approach leverages another important advantage of PP systems, namely the possibility to perform photon-by-photon real-time reconstruction. We demonstrate the application of the approach to perform reconstruction in a simulated 2D SPECT system. The results help to validate and demonstrate the utility of the proposed method and show that PP systems can help overcome the aliasing artifacts that are otherwise intrinsically present in PC systems.
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Affiliation(s)
- Abhinav K Jha
- Division of Medical Imaging Physics, Department of Radiology, Johns Hopkins University, Baltimore, MD 21218, USA
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Van Audenhaege K, Van Holen R, Vandenberghe S, Vanhove C, Metzler SD, Moore SC. Review of SPECT collimator selection, optimization, and fabrication for clinical and preclinical imaging. Med Phys 2015; 42:4796-813. [PMID: 26233207 PMCID: PMC5148182 DOI: 10.1118/1.4927061] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 07/07/2015] [Accepted: 07/08/2015] [Indexed: 01/23/2023] Open
Abstract
In single photon emission computed tomography, the choice of the collimator has a major impact on the sensitivity and resolution of the system. Traditional parallel-hole and fan-beam collimators used in clinical practice, for example, have a relatively poor sensitivity and subcentimeter spatial resolution, while in small-animal imaging, pinhole collimators are used to obtain submillimeter resolution and multiple pinholes are often combined to increase sensitivity. This paper reviews methods for production, sensitivity maximization, and task-based optimization of collimation for both clinical and preclinical imaging applications. New opportunities for improved collimation are now arising primarily because of (i) new collimator-production techniques and (ii) detectors with improved intrinsic spatial resolution that have recently become available. These new technologies are expected to impact the design of collimators in the future. The authors also discuss concepts like septal penetration, high-resolution applications, multiplexing, sampling completeness, and adaptive systems, and the authors conclude with an example of an optimization study for a parallel-hole, fan-beam, cone-beam, and multiple-pinhole collimator for different applications.
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Affiliation(s)
- Karen Van Audenhaege
- Department of Electronics and Information Systems, MEDISIP-IBiTech, Ghent University-iMinds Medical IT, De Pintelaan 185 block B/5, Ghent B-9000, Belgium
| | - Roel Van Holen
- Department of Electronics and Information Systems, MEDISIP-IBiTech, Ghent University-iMinds Medical IT, De Pintelaan 185 block B/5, Ghent B-9000, Belgium
| | - Stefaan Vandenberghe
- Department of Electronics and Information Systems, MEDISIP-IBiTech, Ghent University-iMinds Medical IT, De Pintelaan 185 block B/5, Ghent B-9000, Belgium
| | - Christian Vanhove
- Department of Electronics and Information Systems, MEDISIP-IBiTech, Ghent University-iMinds Medical IT, De Pintelaan 185 block B/5, Ghent B-9000, Belgium
| | - Scott D Metzler
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Stephen C Moore
- Division of Nuclear Medicine, Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115
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Furenlid LR, Barrett HH, Barber HB, Clarkson EW, Kupinski MA, Liu Z, Stevenson GD, Woolfenden JM. Molecular Imaging in the College of Optical Sciences - An Overview of Two Decades of Instrumentation Development. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2014; 9186. [PMID: 26236069 DOI: 10.1117/12.2064808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
During the past two decades, researchers at the University of Arizona's Center for Gamma-Ray Imaging (CGRI) have explored a variety of approaches to gamma-ray detection, including scintillation cameras, solid-state detectors, and hybrids such as the intensified Quantum Imaging Device (iQID) configuration where a scintillator is followed by optical gain and a fast CCD or CMOS camera. We have combined these detectors with a variety of collimation schemes, including single and multiple pinholes, parallel-hole collimators, synthetic apertures, and anamorphic crossed slits, to build a large number of preclinical molecular-imaging systems that perform Single-Photon Emission Computed Tomography (SPECT), Positron Emission Tomography (PET), and X-Ray Computed Tomography (CT). In this paper, we discuss the themes and methods we have developed over the years to record and fully use the information content carried by every detected gamma-ray photon.
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Affiliation(s)
- Lars R Furenlid
- College of Optical Sciences, University of Arizona, Tucson, AZ 85721, USA ; Center for Gamma-Ray Imaging, Dept. of Medical Imaging, University of Arizona, Tucson, AZ 85724, USA
| | - Harrison H Barrett
- College of Optical Sciences, University of Arizona, Tucson, AZ 85721, USA ; Center for Gamma-Ray Imaging, Dept. of Medical Imaging, University of Arizona, Tucson, AZ 85724, USA
| | - H Bradford Barber
- College of Optical Sciences, University of Arizona, Tucson, AZ 85721, USA ; Center for Gamma-Ray Imaging, Dept. of Medical Imaging, University of Arizona, Tucson, AZ 85724, USA
| | - Eric W Clarkson
- College of Optical Sciences, University of Arizona, Tucson, AZ 85721, USA ; Center for Gamma-Ray Imaging, Dept. of Medical Imaging, University of Arizona, Tucson, AZ 85724, USA
| | - Matthew A Kupinski
- College of Optical Sciences, University of Arizona, Tucson, AZ 85721, USA ; Center for Gamma-Ray Imaging, Dept. of Medical Imaging, University of Arizona, Tucson, AZ 85724, USA
| | - Zhonglin Liu
- Center for Gamma-Ray Imaging, Dept. of Medical Imaging, University of Arizona, Tucson, AZ 85724, USA
| | - Gail D Stevenson
- Center for Gamma-Ray Imaging, Dept. of Medical Imaging, University of Arizona, Tucson, AZ 85724, USA
| | - James M Woolfenden
- Center for Gamma-Ray Imaging, Dept. of Medical Imaging, University of Arizona, Tucson, AZ 85724, USA
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Durko HL, Barrett HH, Furenlid LR. High-Resolution Anamorphic SPECT Imaging. IEEE TRANSACTIONS ON NUCLEAR SCIENCE 2014; 61:1126-1135. [PMID: 26160983 PMCID: PMC4494124 DOI: 10.1109/tns.2014.2304853] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have developed a gamma-ray imaging system that combines a high-resolution silicon detector with two sets of movable, half-keel-edged copper-tungsten blades configured as crossed slits. These apertures can be positioned independently between the object and detector, producing an anamorphic image in which the axial and transaxial magnifications are not constrained to be equal. The detector is a 60 mm × 60 mm, one-millimeter-thick, one-megapixel silicon double-sided strip detector with a strip pitch of 59 μm. The flexible nature of this system allows the application of adaptive imaging techniques. We present system details; calibration, acquisition, and reconstruction methods; and imaging results.
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Mejia J, Reis MA, Miranda ACC, Batista IR, Barboza MRF, Shih MC, Fu G, Chen CT, Meng LJ, Bressan RA, Amaro E. Performance assessment of the single photon emission microscope: high spatial resolution SPECT imaging of small animal organs. Braz J Med Biol Res 2013; 46:936-942. [PMID: 24270908 PMCID: PMC3854337 DOI: 10.1590/1414-431x20132764] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 08/21/2013] [Indexed: 01/12/2023] Open
Abstract
The single photon emission microscope (SPEM) is an instrument developed to obtain
high spatial resolution single photon emission computed tomography (SPECT) images of
small structures inside the mouse brain. SPEM consists of two independent imaging
devices, which combine a multipinhole collimator, a high-resolution, thallium-doped
cesium iodide [CsI(Tl)] columnar scintillator, a demagnifying/intensifier tube, and
an electron-multiplying charge-coupling device (CCD). Collimators have 300- and
450-µm diameter pinholes on tungsten slabs, in hexagonal arrays of 19 and 7 holes.
Projection data are acquired in a photon-counting strategy, where CCD frames are
stored at 50 frames per second, with a radius of rotation of 35 mm and magnification
factor of one. The image reconstruction software tool is based on the maximum
likelihood algorithm. Our aim was to evaluate the spatial resolution and sensitivity
attainable with the seven-pinhole imaging device, together with the linearity for
quantification on the tomographic images, and to test the instrument in obtaining
tomographic images of different mouse organs. A spatial resolution better than 500 µm
and a sensitivity of 21.6 counts·s-1·MBq-1 were reached, as
well as a correlation coefficient between activity and intensity better than 0.99,
when imaging 99mTc sources. Images of the thyroid, heart, lungs, and bones
of mice were registered using 99mTc-labeled radiopharmaceuticals in times
appropriate for routine preclinical experimentation of <1 h per projection data
set. Detailed experimental protocols and images of the aforementioned organs are
shown. We plan to extend the instrument's field of view to fix larger animals and to
combine data from both detectors to reduce the acquisition time or applied
activity.
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Affiliation(s)
- J Mejia
- Hospital Israelita Albert Einstein, Instituto do Cérebro, São Paulo,SP, Brasil
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Deleye S, Van Holen R, Verhaeghe J, Vandenberghe S, Stroobants S, Staelens S. Performance evaluation of small-animal multipinhole μSPECT scanners for mouse imaging. Eur J Nucl Med Mol Imaging 2013; 40:744-58. [PMID: 23344137 DOI: 10.1007/s00259-012-2326-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 12/12/2012] [Indexed: 01/13/2023]
Abstract
PURPOSE We compared the performance of three commercial small-animal μSPECT scanners equipped with multipinhole general purpose (GP) and multipinhole high-resolution (HR) collimators designed for imaging mice. METHODS Spatial resolution, image uniformity, point source sensitivity and contrast recovery were determined for the U-SPECT-II (MILabs), the NanoSPECT-NSO (BioScan) and the X-SPECT (GE) scanners. The pinhole diameters of the HR collimator were 0.35 mm, 0.6 mm and 0.5 mm for these three systems respectively. A pinhole diameter of 1 mm was used for the GP collimator. To cover a broad field of imaging applications three isotopes were used with various photon energies: (99m)Tc (140 keV), (111)In (171 and 245 keV) and (125)I (27 keV). Spatial resolution and reconstructed image uniformity were evaluated in both HR and a GP mode with hot rod phantoms, line sources and a uniform phantom. Point source sensitivity and contrast recovery measures were additionally obtained in the GP mode with a novel contrast recovery phantom developed in-house containing hot and cold submillimetre capillaries on a warm background. RESULTS In hot rod phantom images, capillaries as small as 0.4 mm with the U-SPECT-II, 0.75 mm with the X-SPECT and 0.6 mm with the NanoSPECT-NSO could be resolved with the HR collimators for (99m)Tc. The NanoSPECT-NSO achieved this resolution in a smaller field-of-view (FOV) and line source measurements showed that this device had a lower axial than transaxial resolution. For all systems, the degradation in image resolution was only minor when acquiring the more challenging isotopes (111)In and (125)I. The point source sensitivity with (99m)Tc and GP collimators was 3,984 cps/MBq for the U-SPECT-II, 620 cps/MBq for the X-SPECT and 751 cps/MBq for the NanoSPECT-NSO. The effects of volume sensitivity over a larger object were evaluated by measuring the contrast recovery phantom in a realistic FOV and acquisition time. For 1.5-mm rods at a noise level of 8 %, the contrast recovery coefficient (CRC) was 42 %, 37 % and 34 % for the U-SPECT-II, X-SPECT and NanoSPECT-NSO, respectively. At maximal noise levels of 10 %, a CRCcold of 70 %, 52 % and 42 % were obtained for the U-SPECT-II, X-SPECT and NanoSPECT-NSO, respectively. When acquiring (99m)Tc with the GP collimators, the integral/differential uniformity values were 30 %/14 % for the U-SPECT-II, 50 %/30 % for the X-SPECT and 38 %/25 % for the NanoSPECT-NSO. When using the HR collimators, these uniformity values remained similar for U-SPECT-II and X-SPECT, but not for the NanoSPECT-NSO for which the uniformity deteriorated with larger volumes. CONCLUSION We compared three μSPECT systems by acquiring and analysing mouse-sized phantoms including a contrast recovery phantom built in-house offering the ability to measure the hot contrast on a warm background in the submillimetre resolution range. We believe our evaluation addressed the differences in imaging potential for each system to realistically image tracer distributions in mouse-sized objects.
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Affiliation(s)
- Steven Deleye
- Molecular Imaging Center Antwerp, Antwerp University, Universiteitsplein 1, 2610 Antwerp, Belgium.
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11
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Reis MAD, Mejia J, Batista IR, Barboza MRFFD, Nogueira SA, Wagner J, Cabral FR, Davoglio PMVM, Abílio VC, Fu G, Li N, Meng LJ, Shih MC, Chen CT, Amaro Junior E, Bressan RA. SPEM: a state-of-the-art instrument for high resolution molecular imaging of small animal organs. EINSTEIN-SAO PAULO 2012; 10:209-15. [PMID: 23052457 DOI: 10.1590/s1679-45082012000200015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 05/07/2012] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE To describe the Single Photon Emission Microscope (SPEM), a state-of-the-art instrument for small animal SPECT imaging, and characterize its performance presenting typical images of different animal organs. METHODS SPEM consists of two independent imaging devices based on high resolution scintillators, high sensitivity and resolution Electron-Multiplying CCDs and multi-pinhole collimators. During image acquisition, the mouse is placed in a rotational vertical holder between the imaging devices. Subsequently, an appropriate software tool based on the Maximum Likelihood algorithm iteratively produces the volumetric image. Radiopharmaceuticals for imaging kidneys, heart, thyroid and brain were used. The mice were injected with 74 to 148 MBq/0,3mL and scanned for 40 to 80 minutes, 30 to 60 minutes afterwards. During this procedure, the animals remained under ketamine/xilazine anesthesia. RESULTS SPEM images of different mouse organs are presented, attesting the imaging capabilities of the instrument. CONCLUSION SPEM is an innovative technology for small animal SPECT imaging providing high resolution images with appropriate sensitivity for pre-clinical research. Its use with appropriate radiotracers will allow translational investigation of several animal models of human diseases, their pharmacological treatment and the development of potential new therapeutic agents.
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Miller BW, Van Holen R, Barrett HH, Furenlid LR. A System Calibration and Fast Iterative Reconstruction Method for Next-Generation SPECT Imagers. IEEE TRANSACTIONS ON NUCLEAR SCIENCE 2012; 59:1990-1996. [PMID: 26236041 PMCID: PMC4520546 DOI: 10.1109/tns.2012.2198243] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Recently, high-resolution gamma cameras have been developed with detectors containing > 105-106 elements. Single-photon emission computed tomography (SPECT) imagers based on these detectors usually also have a large number of voxel bins and therefore face memory storage issues for the system matrix when performing fast tomographic reconstructions using iterative algorithms. To address these issues, we have developed a method that parameterizes the detector response to a point source and generates the system matrix on the fly during MLEM or OSEM on graphics hardware. The calibration method, interpolation of coefficient data, and reconstruction results are presented in the context of a recently commissioned small-animal SPECT imager, called FastSPECT III.
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Affiliation(s)
- Brian W. Miller
- Center for Gamma-Ray Imaging and the College of Optical Sciences, University of Arizona, Tucson, AZ 85724 USA
| | - Roel Van Holen
- MEDISIP, Department of Electronics and Information Systems, Ghent University, B-9000 Ghent, Belgium
| | - Harrison H. Barrett
- Center for Gamma-Ray Imaging and the College of Optical Sciences, University of Arizona, Tucson, AZ 85724 USA
| | - Lars R. Furenlid
- Center for Gamma-Ray Imaging and the College of Optical Sciences, University of Arizona, Tucson, AZ 85724 USA
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Miller BW, Moore JW, Barrett HH, Fryé T, Adler S, Sery J, Furenlid LR. 3D printing in X-ray and Gamma-Ray Imaging: A novel method for fabricating high-density imaging apertures. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT 2011; 659:262-268. [PMID: 22199414 PMCID: PMC3244175 DOI: 10.1016/j.nima.2011.08.051] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Advances in 3D rapid-prototyping printers, 3D modeling software, and casting techniques allow for cost-effective fabrication of custom components in gamma-ray and X-ray imaging systems. Applications extend to new fabrication methods for custom collimators, pinholes, calibration and resolution phantoms, mounting and shielding components, and imaging apertures. Details of the fabrication process for these components, specifically the 3D printing process, cold casting with a tungsten epoxy, and lost-wax casting in platinum are presented.
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Affiliation(s)
- Brian W. Miller
- Center for Gamma-Ray Imaging, The University of Arizona, Tucson, Arizona 85719, USA
- Corresponding author (Brian W. Miller), URL: http://www.gamma.radiology.arizona.edu (Brian W. Miller), Tel.: +1 520 626 2957 (Brian W. Miller), fax: +1 520 626 2892 (Brian W. Miller)
| | - Jared W. Moore
- Center for Gamma-Ray Imaging, The University of Arizona, Tucson, Arizona 85719, USA
| | - Harrison H. Barrett
- Center for Gamma-Ray Imaging, The University of Arizona, Tucson, Arizona 85719, USA
| | - Teresa Fryé
- TechForm Advanced Casting Technology, LLC, Portland, Oregon 97222, USA
| | | | - Joe Sery
- Tungsten Heavy Powder, San Diego, California 92121, USA
| | - Lars R. Furenlid
- Center for Gamma-Ray Imaging, The University of Arizona, Tucson, Arizona 85719, USA
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Miller BW, Van Holen R, Barrett HH, Furenlid LR. A System Calibration and Fast Iterative Reconstruction Method for Next-Generation SPECT Imagers. IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD. NUCLEAR SCIENCE SYMPOSIUM 2011; 2011:3548-3553. [PMID: 26568672 DOI: 10.1109/nssmic.2011.6153666] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Recently, high-resolution gamma cameras have been developed with detectors containing> 105-106 elements. SPECT imagers based on these detectors usually also have a large number of voxel bins and therefore face memory storage issues for the system matrix when performing fast tomographic reconstructions using iterative algorithms. To address these issues, we have developed a method that parameterizes the detector response to a point source and generates the system matrix on the fly during MLEM or OSEM on graphics hardware. The calibration method, interpolation of coefficient data, and reconstruction results are presented in the context of a recently commissioned small-animal SPECT imager, called FastSPECT III.
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Affiliation(s)
- Brian W Miller
- Center for Gamma-Ray Imaging and the College of Optical Sciences, University of Arizona, Tucson, AZ 85724 USA
| | - Roel Van Holen
- MEDISIP, Department of Electronics and Information Systems, Ghent University, B-9000 Ghent, Belgium. He is supported by a postdoctoral fellowship of the Research Foundation (FWO)
| | - Harrison H Barrett
- Center for Gamma-Ray Imaging and the College of Optical Sciences, University of Arizona, Tucson, AZ 85724 USA
| | - Lars R Furenlid
- Center for Gamma-Ray Imaging and the College of Optical Sciences, University of Arizona, Tucson, AZ 85724 USA
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Durko HL, Peterson TE, Barrett HH, Furenlid LR. High-resolution, anamorphic, adaptive small-animal SPECT imaging with silicon double-sided strip detectors. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2011; 8143. [PMID: 26346619 DOI: 10.1117/12.896729] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
We are developing a prototype gamma-ray imaging system that consists of two sets of movable, keel-edged copper-tungsten blades configured as crossed slits. These apertures can be positioned independently between the object and detector, producing an anamorphic image in which the axial and transaxial magnifications are not constrained to be equal. The detector is a 60 mm × 60 mm, millimeter thick, one-megapixel silicon double-sided strip detector. The flexible nature of this system allows the application of adaptive imaging techniques. We will discuss system details, calibration and acquisition methods, and our progress towards biological imaging applications.
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Affiliation(s)
- Heather L Durko
- University of Arizona, Center for Gamma-Ray Imaging, Tucson AZ, USA
| | - Todd E Peterson
- Vanderbilt University, Institute of Imaging Science, Nashville TN, USA
| | | | - Lars R Furenlid
- University of Arizona, Center for Gamma-Ray Imaging, Tucson AZ, USA
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Abstract
The development of radiation detectors capable of delivering spatial information about gamma-ray interactions was one of the key enabling technologies for nuclear medicine imaging and, eventually, single-photon emission computed tomography (SPECT). The continuous sodium iodide scintillator crystal coupled to an array of photomultiplier tubes, almost universally referred to as the Anger Camera after its inventor, has long been the dominant SPECT detector system. Nevertheless, many alternative materials and configurations have been investigated over the years. Technological advances as well as the emerging importance of specialized applications, such as cardiac and preclinical imaging, have spurred innovation such that alternatives to the Anger Camera are now part of commercial imaging systems. Increased computing power has made it practical to apply advanced signal processing and estimation schemes to make better use of the information contained in the detector signals. In this review we discuss the key performance properties of SPECT detectors and survey developments in both scintillator and semiconductor detectors and their readouts with an eye toward some of the practical issues at least in part responsible for the continuing prevalence of the Anger Camera in the clinic.
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Affiliation(s)
- Todd E Peterson
- Institute of Imaging Science, Department of Radiology and Radiological Sciences, Department of Physics, and Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN, USA.
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Miller BW, Moore JW, Gehm ME, Furenlid LR, Barrett HH. Novel Applications of Rapid Prototyping in Gamma-ray and X-ray Imaging. IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD. NUCLEAR SCIENCE SYMPOSIUM 2009; 2009:3322-3326. [PMID: 22984341 PMCID: PMC3439818 DOI: 10.1109/nssmic.2009.5401745] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Advances in 3D rapid-prototyping printers, 3D modeling software, and casting techniques allow for the fabrication of cost-effective, custom components in gamma-ray and x-ray imaging systems. Applications extend to new fabrication methods for custom collimators, pinholes, calibration and resolution phantoms, mounting and shielding components, and imaging apertures. Details of the fabrication process for these components are presented, specifically the 3D printing process, cold casting with a tungsten epoxy, and lost-wax casting in platinum.
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Affiliation(s)
- Brian W Miller
- B. W. Miller and J. W. Moore are with the College of Optical Sciences, L. R. Furenlid, H. H. Barrett, and H. B. Barber, are with the Department of Radiology Research and College of Optical Sciences, and M. E. Gehm is with the Department of Electrical and Computer Engineering and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 USA
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