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Katsuragawa M, Yagishita A, Takeda S, Minami T, Ohnuki K, Fujii H, Takahashi T. CdTe XG-Cam: A new high-resolution x-ray and gamma-ray camera for studies of the pharmacokinetics of radiopharmaceuticals in small animals. Med Phys 2024; 51:5308-5320. [PMID: 38762908 DOI: 10.1002/mp.17124] [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: 11/09/2023] [Revised: 03/29/2024] [Accepted: 04/22/2024] [Indexed: 05/21/2024] Open
Abstract
BACKGROUND The recent emergence of targeted radionuclide therapy has increased the demand for imagers capable of visualizing pharmacokinetics in developing radiopharmaceuticals in the preclinical phase. Some radionuclides emit hard x-rays and gamma-rays below 100 keV, in which energy range the performance of conventional NaI scintillators is poor. Multipinhole collimators are also used for small animal imaging with a good spatial resolution but have a limited field of view (FOV). PURPOSE In this study, a new imager with high sensitivity over a wide FOV in the low-energy band ( < $<$ 100 keV) was developed for the pharmacokinetic study. METHODS We developed an x-ray and gamma-ray camera for high-resolution spectroscopy, named "CdTe XG-Cam," equipped with a cadmium telluride semiconductor detector and a parallel-hole collimator using a metal 3D printer. To evaluate the camera-system performance, phantom measurements with single and dual nuclides (99 m Tc $^{\rm 99m}{\rm Tc}$ ,111 In $^{111}{\rm In}$ , and125 I ) $^{125}{\rm I)}$ were performed. The performance for in vivo imaging was evaluated using tumor-bearing mice to which a nuclide (99 m Tc $^{\rm 99m}{\rm Tc}$ or125 I ) $^{125}{\rm I)}$ administered. RESULTS We simultaneously obtained information on111 In $^{111}{\rm In}$ and125 I $^{125}{\rm I}$ , which emit emission lines in the low-energy band with peak energies close to each other (23-26 keV for111 In $^{111}{\rm In}$ and 27-31 keV for125 I ) $^{125}{\rm I)}$ , and applied an analytical method based on spectral model fitting to determine the individual radioactivities accurately. In the small animal imaging, the distributions of the nuclide in tumors were accurately quantified and time-activity curves in tumors are obtained. CONCLUSIONS The demonstrated capability of our system to perform in vivo imaging suggests that the camera can be used for applications of pharmacokinetics research.
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Affiliation(s)
- Miho Katsuragawa
- Kavli Institute for the Physics and Mathematics of the Universe (IPMU) (WPI), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, Kashiwa, Chiba, Japan
| | - Atsushi Yagishita
- Kavli Institute for the Physics and Mathematics of the Universe (IPMU) (WPI), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, Kashiwa, Chiba, Japan
- iMAGINE-X Inc., Shibuya-ku, Tokyo, Japan
| | - Shin'ichiro Takeda
- Kavli Institute for the Physics and Mathematics of the Universe (IPMU) (WPI), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, Kashiwa, Chiba, Japan
- iMAGINE-X Inc., Shibuya-ku, Tokyo, Japan
| | - Takahiro Minami
- Kavli Institute for the Physics and Mathematics of the Universe (IPMU) (WPI), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, Kashiwa, Chiba, Japan
- Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Kazunobu Ohnuki
- Division of Functional Imaging, The National Cancer Center Japan, Kashiwa, Chiba, Japan
| | - Hirofumi Fujii
- Division of Functional Imaging, The National Cancer Center Japan, Kashiwa, Chiba, Japan
| | - Tadayuki Takahashi
- Kavli Institute for the Physics and Mathematics of the Universe (IPMU) (WPI), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, Kashiwa, Chiba, Japan
- Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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Pirayesh Islamian J, Ljungberg M. Evaluation of Improved Imaging Properties with Tungsten-Based Parallel-Hole Collimators: A Monte Carlo Study. World J Nucl Med 2024; 23:95-102. [PMID: 38933066 PMCID: PMC11199031 DOI: 10.1055/s-0044-1786165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2024] Open
Abstract
Objectives The purpose of a parallel-hole collimator in a scintillation camera system is to transmit only those photons that have an emission angle close to the direction of the hole. This makes it possible to receive spatial information about the origin of the emission, that is, radioactivity decay. The dimension, shape, and intrahole thickness determine the spatial resolution and, by a tradeoff, sensitivity. The composition of the collimator material also plays an important role in determining a proper collimator. In this study, we compared tungsten alloys as a potential collimator material replacement for the conventional lead antimony material used in most of the current camera systems. Materials and Methods Monte Carlo simulations of a commercial scintillation camera system with low energy high resolution (LEHR), medium-energy (ME), and high-energy (HE) collimators of lead, tungsten, and tungsten-based alloy were simulated for different I-131, Lu-177, I-123, and Tc-99m sources, and a Deluxe rod phantom using the SIMIND Monte Carlo code. Planar images were analyzed regarding spatial resolution, image contrast in a cold source case, and system sensitivity for each collimator configuration. The hole dimensions for the three collimators were those specified in the vendor's datasheet. Results Using Pb, W, and tungsten alloy (Wolfmet) as collimator materials, the full width at half maximum (FWHM) measures for total counts (T) for LEHR with Tc-99m source (6.9, 6.8, and 6.8 mm), for ME with Lu-177 source (11.7, 11.5, and 11.6 mm), and for HE with I-131 (6.2, 13.1, and 13.1 mm) were obtained, and the system sensitivities were calculated as 89.9, 86.1, and 89.8 cps T /MBq with Tc-99m source; 42.7, 17.4, and 20.9 cps T /MBq with Lu-177 source; and 40.1, 69.7, and 77.4 cps T /MBq with I-131 source. The collimators of tungsten and tungsten alloy (97.0% W, 1.5% Fe, 1.5% Ni) provided better spatial resolution and improved image contrast when compared with conventional lead-based collimators. This was due to lower septal penetration. Conclusion The results suggest that development of a new set of ME and HE tungsten and tungsten alloy collimators could improve imaging of I-131, Lu-177, and I-123.
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Affiliation(s)
- Jalil Pirayesh Islamian
- Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Michael Ljungberg
- Department of Medical Radiation Physics, Lund, Lund University, Lund, Sweden
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Higuchi T, Chen X, Werner RA. Navigating new horizons: Prospects of NET-targeted radiopharmaceuticals in precision medicine. Theranostics 2024; 14:3178-3192. [PMID: 38855189 PMCID: PMC11155404 DOI: 10.7150/thno.96743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 04/23/2024] [Indexed: 06/11/2024] Open
Abstract
In the evolving landscape of precision medicine, NET-targeted radiopharmaceuticals are emerging as pivotal tools for the diagnosis and treatment of a range of conditions, from heart failure and neurodegenerative disorders to neuroendocrine cancers. This review evaluates the advancements offered by 18F-labeled PET tracers and 211At alpha-particle therapy, juxtaposed with current 123I-MIBG SPECT and 131I-MIBG therapies. The enhanced spatial resolution and capability for quantitative analysis render 18F-labeled PET tracers potential candidates for improved detection and management of diseases. Alpha-particle therapy with 211At may offer increased specificity and tumoricidal efficacy, pointing towards a shift in therapeutic protocols. While preliminary data is promising, these innovative approaches require thorough validation against current modalities. Ongoing clinical trials are pivotal to confirm the expected clinical benefits and to address safety concerns. This review underscores the need for rigorous research to verify the clinical utility of NET-targeted radiopharmaceuticals, which may redefine precision medicine paradigms and significantly impact patient care.
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Affiliation(s)
- Takahiro Higuchi
- Department of Nuclear Medicine and Comprehensive Heart Failure Center, University Hospital of Würzburg, Würzburg, Germany
- Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Xinyu Chen
- Nuclear Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany
| | - Rudolf A Werner
- DZHK (German Centre for Cardiovascular Research), Partner Site Frankfurt Rhine-Main, Frankfurt, Germany
- Goethe University Frankfurt, Department of Nuclear Medicine, Clinic for Radiology and Nuclear Medicine, Frankfurt, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt/Mainz and German Cancer Research Center (DKFZ), Heidelberg, Germany
- The Russell H Morgan Department of Radiology and Radiological Sciences, Division of Nuclear Medicine and Molecular Imaging, Johns Hopkins School of Medicine, Baltimore, MD, United States
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Buchert R, Szabo B, Kovacs A, Buddenkotte T, Mathies F, Karimzadeh A, Lehnert W, Klutmann S, Forgacs A, Apostolova I. Dopamine Transporter SPECT with 12-Minute Scan Duration Using Multiple-Pinhole Collimators. J Nucl Med 2024; 65:446-452. [PMID: 38238040 DOI: 10.2967/jnumed.123.266276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 11/28/2023] [Indexed: 03/03/2024] Open
Abstract
This study evaluated the potential to reduce the scan duration in dopamine transporter (DAT) SPECT when using a second-generation multiple-pinhole (MPH) collimator designed for brain SPECT with improved count sensitivity and improved spatial resolution compared with parallel-hole and fanbeam collimators. Methods: The retrospective study included 640 consecutive clinical DAT SPECT studies that had been acquired in list mode with a triple-head SPECT system with MPH collimators and a 30-min net scan duration after injection of 181 ± 10 MBq of [123I]FP-CIT. Raw data corresponding to scan durations of 20, 15, 12, 8, 6, and 4 min were obtained by restricting the events to a proportionally reduced time interval of the list-mode data for each projection angle. SPECT images were reconstructed iteratively with the same parameter settings irrespective of scan duration. The resulting 5,120 SPECT images were assessed for a neurodegeneration-typical reduction in striatal signal by visual assessment, conventional specific binding ratio analysis, and a deep convolutional neural network trained on 30-min scans. Results: Regarding visual interpretation, image quality was considered diagnostic for all 640 patients down to a 12-min scan duration. The proportion of discrepant visual interpretations between 30 and 12 min (1.2%) was not larger than the proportion of discrepant visual interpretations between 2 reading sessions of the same reader at a 30-min scan duration (1.5%). Agreement with the putamen specific binding ratio from the 30-min images was better than expected for 5% test-retest variability down to a 10-min scan duration. A relevant change in convolutional neural network-based automatic classification was observed at a 6-min scan duration or less. Conclusion: The triple-head SPECT system with MPH collimators allows reliable DAT SPECT after administration of about 180 MBq of [123I]FP-CIT with a 12-min scan duration.
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Affiliation(s)
- Ralph Buchert
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and
| | - Balazs Szabo
- Mediso Medical Imaging Systems, Budapest, Hungary
| | - Akos Kovacs
- Mediso Medical Imaging Systems, Budapest, Hungary
| | - Thomas Buddenkotte
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and
| | - Franziska Mathies
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and
| | - Amir Karimzadeh
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and
| | - Wencke Lehnert
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and
| | - Susanne Klutmann
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and
| | | | - Ivayla Apostolova
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and
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Sharma S, Pandey MK. Radiometals in Imaging and Therapy: Highlighting Two Decades of Research. Pharmaceuticals (Basel) 2023; 16:1460. [PMID: 37895931 PMCID: PMC10610335 DOI: 10.3390/ph16101460] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 10/03/2023] [Accepted: 10/05/2023] [Indexed: 10/29/2023] Open
Abstract
The present article highlights the important progress made in the last two decades in the fields of molecular imaging and radionuclide therapy. Advancements in radiometal-based positron emission tomography, single photon emission computerized tomography, and radionuclide therapy are illustrated in terms of their production routes and ease of radiolabeling. Applications in clinical diagnostic and radionuclide therapy are considered, including human studies under clinical trials; their current stages of clinical translations and findings are summarized. Because the metalloid astatine is used for imaging and radionuclide therapy, it is included in this review. In regard to radionuclide therapy, both beta-minus (β-) and alpha (α)-emitting radionuclides are discussed by highlighting their production routes, targeted radiopharmaceuticals, and current clinical translation stage.
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Affiliation(s)
| | - Mukesh K. Pandey
- Division of Nuclear Medicine, Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA;
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Frame E, Bobba K, Gunter D, Mihailescu L, Bidkar A, Flavell R, Vetter K. Coded aperture and Compton imaging for the development of 225 Ac-based radiopharmaceuticals. Med Phys 2023; 50:6454-6468. [PMID: 37672346 DOI: 10.1002/mp.16717] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/20/2023] [Accepted: 07/30/2023] [Indexed: 09/08/2023] Open
Abstract
BACKGROUND Targeted alpha-particle therapy (TAT) has great promise as a cancer treatment. Arguably the most promising TAT radionuclide that has been proposed is 225 Ac. The development of 225 Ac-based radiopharmaceuticals has been hampered due to the lack of effective means to study the daughter redistribution of these agents in small animals at the preclinical stage. PURPOSE The ability to directly image the daughters, namely 221 Fr and 213 Bi, via their gamma-ray emissions would be a boon for preclinical studies. That said, conventional medical imaging modalities, including single photon emission computed tomography (SPECT) based on nonmultiplexed collimation, cannot be employed due to sensitivity limitations. METHODS As an alternative, we propose the use of both coded aperture and Compton imaging with the former modality suited to the 218-keV gamma-ray emission of 221 Fr and the latter suited to the 440-keV gamma-ray emission of 213 Bi. RESULTS This work includes coded aperture images of 221 Fr and Compton images of 213 Bi in tumor-bearing mice injected with 225 Ac-based radiopharmaceuticals. CONCLUSIONS These results are the first demonstration of visualizing and quantifying the 225 Ac daughters in small animals through the application of coded aperture and Compton imaging.
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Affiliation(s)
- Emily Frame
- Department of Nuclear Engineering, University of California Berkeley, Berkeley, California, USA
| | - Kondapa Bobba
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Donald Gunter
- Gunter Physics, Inc., Illinois, USA
- Applied Nuclear Physics Group, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | | | - Anil Bidkar
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Robert Flavell
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Kai Vetter
- Department of Nuclear Engineering, University of California Berkeley, Berkeley, California, USA
- Applied Nuclear Physics Group, Lawrence Berkeley National Laboratory, Berkeley, California, USA
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Sheng J, Huang P, Zhou R, Li Z, Yang X, Wang J. A novel reconstruction method combining multi-detector SPECT with an elliptical orbit and computer tomography for cardiac imaging. Sci Rep 2023; 13:15005. [PMID: 37696930 PMCID: PMC10495346 DOI: 10.1038/s41598-023-42163-5] [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: 06/24/2023] [Accepted: 09/06/2023] [Indexed: 09/13/2023] Open
Abstract
The myocardial single photon emission computed tomography (SPECT) is a good study due to its clinical significance in the diagnosis of myocardial disease and the requirement for improving image quality. However, SPECT imaging faces challenges related to low spatial resolution and significant statistical noise, which concerns patient radiation safety. In this paper, a novel reconstruction system combining multi-detector elliptical SPECT (ME-SPECT) and computer tomography (CT) is proposed to enhance spatial resolution and sensitivity. The hybrid imaging system utilizes a slit-slat collimator and elliptical orbit to improve sensitivity and signal-to-noise ratio (SNR), obtains accurate attenuation mapping matrices, and requires prior information from integrated CT. Collimator parameters are corrected based on CT reconstruction results. The SPECT imaging system employs an iterative reconstruction algorithm that utilizes prior knowledge. An iterative reconstruction algorithm based on prior knowledge is applied to the SPECT imaging system, and a method for prioritizing the reconstruction of regions of interest (ROI) is introduced to deal with severely truncated data from ME-SPECT. Simulation results show that the proposed method can significantly improve the system's spatial resolution, SNR, and image fidelity. The proposed method can effectively suppress distortion and artifacts with the higher spatial resolution ordered subsets expectation maximization (OSEM); slit-slat collimation.
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Affiliation(s)
- Jinhua Sheng
- School of Computer Science and Technology, Hangzhou Dianzi University, Hangzhou, 310018, Zhejiang, China.
- Key Laboratory of Intelligent Image Analysis for Sensory and Cognitive Health, Ministry of Industry and Information Technology of China, Hangzhou, 310018, Zhejiang, China.
| | - Pu Huang
- School of Computer Science and Technology, Hangzhou Dianzi University, Hangzhou, 310018, Zhejiang, China
- Key Laboratory of Intelligent Image Analysis for Sensory and Cognitive Health, Ministry of Industry and Information Technology of China, Hangzhou, 310018, Zhejiang, China
| | - Rougang Zhou
- College of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou, 310018, Zhejiang, China
- Mstar Technologies Inc, Hangzhou, 310018, Zhejiang, China
| | - Zhongjin Li
- School of Computer Science and Technology, Hangzhou Dianzi University, Hangzhou, 310018, Zhejiang, China
- Key Laboratory of Intelligent Image Analysis for Sensory and Cognitive Health, Ministry of Industry and Information Technology of China, Hangzhou, 310018, Zhejiang, China
| | - Xiaofan Yang
- School of Computer Science and Technology, Hangzhou Dianzi University, Hangzhou, 310018, Zhejiang, China
- Key Laboratory of Intelligent Image Analysis for Sensory and Cognitive Health, Ministry of Industry and Information Technology of China, Hangzhou, 310018, Zhejiang, China
| | - Jialei Wang
- School of Computer Science and Technology, Hangzhou Dianzi University, Hangzhou, 310018, Zhejiang, China
- Key Laboratory of Intelligent Image Analysis for Sensory and Cognitive Health, Ministry of Industry and Information Technology of China, Hangzhou, 310018, Zhejiang, China
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Zhang D, Lyu Z, Liu Y, He ZX, Yao R, Ma T. Characterization and Assessment of Projection Probability Density Function and Enhanced Sampling in Self-Collimation SPECT. IEEE TRANSACTIONS ON MEDICAL IMAGING 2023; 42:2787-2801. [PMID: 37037258 PMCID: PMC10597595 DOI: 10.1109/tmi.2023.3265874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
We have recently reported a self-collimation SPECT (SC-SPECT) design concept that constructs sensitive detectors in a multi-ring interspaced mosaic architecture to simultaneously improve system spatial resolution and sensitivity. In this work, through numerical and Monte-Carlo simulation studies, we investigate this new design concept by analyzing its projection probability density functions (PPDF) and the effects of enhanced sampling, i.e. having rotational and translational object movements during imaging. We first quantitatively characterize PPDFs by their widths and edge slopes. Then we compare the PPDFs of an SC-SPECT and a series of multiple-pinhole SPECT (MPH-SPECT) systems and assess the impact of PPDFs - combined with enhanced sampling - on image contrast recovery coefficient and variance through phantom studies. We show the PPDFs of SC- SPECT have steeper edges and a wider range of width, and these attributes enable SC-SPECT to achieve better performance.
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Nekolla SG, Rischpler C, Higuchi T. Preclinical Imaging of Cardiovascular Disesase. Semin Nucl Med 2023; 53:586-598. [PMID: 37268498 DOI: 10.1053/j.semnuclmed.2023.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 06/04/2023]
Abstract
Noninvasive imaging techniques, such as SPECT, PET, CT, echocardiography, or MRI, have become essential in cardiovascular research. They allow for the evaluation of biological processes in vivo without the need for invasive procedures. Nuclear imaging methods, such as SPECT and PET, offer numerous advantages, including high sensitivity, reliable quantification, and the potential for serial imaging. Modern SPECT and PET imaging systems, equipped with CT and MRI components in order to get access to morphological information with high spatial resolution, are capable of imaging a wide range of established and innovative agents in both preclinical and clinical settings. This review highlights the utility of SPECT and PET imaging as powerful tools for translational research in cardiology. By incorporating these techniques into a well-defined workflow- similar to those used in clinical imaging- the concept of "bench to bedside" can be effectively implemented.
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Affiliation(s)
- Stephan G Nekolla
- Nuklearmedizinische Klinik der TU München, Munich, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany.
| | | | - Takahiro Higuchi
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany; Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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Darami M, Mahmoudian B, Ljungberg M, Pirayesh Islamian J. Impact of Wolfmet Tungsten Alloys as Parallel-Hole Collimator Material on Single-Photon Emission Computed Tomography Image Quality and Functional Parameters: A Simulating Medical Imaging Nuclear Detectors Monte Carlo Study. World J Nucl Med 2023; 22:217-225. [PMID: 37854088 PMCID: PMC10581757 DOI: 10.1055/s-0043-1771287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023] Open
Abstract
Objectives Collimators have a significant role in image quality and detectability in single-photon emission computed tomography (SPECT) imaging. Using an appropriate alloy that effectively absorbs scattered photons, without induced secondary x-rays, and with proper rigidity and weight may provide an effective approach to the image improvement that conventionally collimators made of lead (Pb). Materials and Methods A Siemens E.CAM SPECT imaging system equipped with low-energy high-resolution (LEHR) collimator was simulated by the Simulating Medical Imaging Nuclear Detectors Monte Carlo program. Experimental and simulated data were compared based on a 2-mm 99m Tc point source in an acrylic cylindrical Deluxe phantom (Data Spectrum, Inc). Seven types of tungsten (W) alloys (Wolfmet), with W content from 90 to 97% by weight, were then used as collimator materials of the simulated system. Camera parameters, such as energy- and spatial resolution, image contrast, and collimator-related parameters, such as fraction of septal penetration, scatter-to-primary ratios, and percentage of induced secondary x-rays, due to interactions in the collimator, were evaluated. Results Acceptable conformity was found for the simulated and experiment systems in terms of energy spectra, 10.113 and 10.140%, full width at half-maximum (FWHM) of the point spread function (PSF) curves, 8.78 and 9.06 mm, sensitivity, 78.46 and 78.34 cps/MBq, and contrast in images of 19.1 mm cold spheres in the Deluxe phantom, 79.17 and 78.97%, respectively. Results on the parameters of the simulated system with LEHR collimator made from the alloys showed that the alloy consisting of 90% W, 6% nickel, and 4% copper provided an FWHM of 8.76 mm, resulting in a 0.2% improvement in spatial resolution. Furthermore, all the Wolfmet collimators showed a 48% reduction in the amount of X-rays production compared to the Pb. Conclusion A Wolfmet LEHR collimator, made by a combination of W (90%), Ni (6%), and Cu (6%) provides a better image quality and detectability compared to the Pb.
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Affiliation(s)
- Maryam Darami
- Medical Radiation Sciences Research Team, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Babak Mahmoudian
- Department of Nuclear Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Jalil Pirayesh Islamian
- Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
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Wu W, Zhang R, Zhou Y, Wang S, Shen Y, Li N, Tan J, Zheng W, Jia Q, Meng Z. Impacts of different reconstruction methods on the image quality of cadmium-zinc-telluride-based single photon emission computed tomography/computed tomography pulmonary perfusion imaging. Nucl Med Commun 2023; 44:673-681. [PMID: 37233601 DOI: 10.1097/mnm.0000000000001710] [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: 05/27/2023]
Abstract
OBJECTIVE The objective was to evaluate the impacts of different reconstruction methods [filtered back projection (FBP) and ordered subset expectation maximization (OSEM)] and different filters (Butterworth filter and Gaussian filter) on the image quality in cadmium-zinc-telluride (CZT)-based single photon emission computed tomography (SPECT)/computed tomography (CT) pulmonary perfusion imaging. METHODS A combinations including FBP with Butterworth filter, OSEM with Butterworth filter (OSEM + Butterworth filter ), and OSEM with Gaussian filter (OSEM + Gaussian filter) were used during SPECT image reconstruction. Visual and quantitative parameters [root mean square (RMS) noise, contrast and contrast-to-noise ratio (CNR)] were used to evaluate image quality. RESULTS The OSEM + Gaussian filter had better RMS noise and CNR than those of the FBP + Butterworth filter or OSEM + Butterworth filter, while the OSEM + Butterworth filter had the best contrast. The highest visual scores were obtained by OSEM + Gaussian filter ( P < 0.0001). In the lesion size <2 cm group, the contrast ( P < 0.01) and visual scores ( P < 0.001) of OSEM + Butterworth filter were better than those of the other two groups. In the lesion size ≥2 cm group, the RMS noise and visual scores of OSEM + Gaussian filter were better than those of the other two groups. CONCLUSION In CZT SPECT/CT pulmonary perfusion imaging, this study recommended the clinical use of the OSEM + Gaussian filter combination for reconstruction in both conventional and larger lesions, the OSEM + Butterworth filter image postprocessing method might be advantageous in small lesions.
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Affiliation(s)
- Weiming Wu
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Tianjin
| | - Ruyi Zhang
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Tianjin
| | - Yaqian Zhou
- Department of Nuclear Medicine, Renji Hospital Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shen Wang
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Tianjin
| | - Yiming Shen
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Tianjin
| | - Ning Li
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Tianjin
| | - Jian Tan
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Tianjin
| | - Wei Zheng
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Tianjin
| | - Qiang Jia
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Tianjin
| | - Zhaowei Meng
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Tianjin
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12
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Nowak-Jary J, Machnicka B. In vivo Biodistribution and Clearance of Magnetic Iron Oxide Nanoparticles for Medical Applications. Int J Nanomedicine 2023; 18:4067-4100. [PMID: 37525695 PMCID: PMC10387276 DOI: 10.2147/ijn.s415063] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 06/29/2023] [Indexed: 08/02/2023] Open
Abstract
Magnetic iron oxide nanoparticles (magnetite and maghemite) are intensively studied due to their broad potential applications in medical and biological sciences. Their unique properties, such as nanometric size, large specific surface area, and superparamagnetism, allow them to be used in targeted drug delivery and internal radiotherapy by targeting an external magnetic field. In addition, they are successfully used in magnetic resonance imaging (MRI), hyperthermia, and radiolabelling. The appropriate design of nanoparticles allows them to be delivered to the desired tissues and organs. The desired biodistribution of nanoparticles, eg, cancerous tumors, is increased using an external magnetic field. Thus, knowledge of the biodistribution of these nanoparticles is essential for medical applications. It allows for determining whether nanoparticles are captured by the desired organs or accumulated in other tissues, which may lead to potential toxicity. This review article presents the main organs where nanoparticles accumulate. The sites of their first uptake are usually the liver, spleen, and lymph nodes, but with the appropriate design of nanoparticles, they can also be accumulated in organs such as the lungs, heart, or brain. In addition, the review describes the factors affecting the biodistribution of nanoparticles, including their size, shape, surface charge, coating molecules, and route of administration. Modern techniques for determining nanoparticle accumulation sites and concentration in isolated tissues or the body in vivo are also presented.
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Affiliation(s)
- Julia Nowak-Jary
- University of Zielona Gora, Faculty of Biological Sciences, Department of Biotechnology, Zielona Gora, 65-516, Poland
| | - Beata Machnicka
- University of Zielona Gora, Faculty of Biological Sciences, Department of Biotechnology, Zielona Gora, 65-516, Poland
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13
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Wang R, Zhang D, Hu Y, Lyu Z, Ma T. High-sensitivity cardiac SPECT system design with collimator-less interspaced mosaic-patterned scintillators. Front Med (Lausanne) 2023; 10:1145351. [PMID: 37448793 PMCID: PMC10336213 DOI: 10.3389/fmed.2023.1145351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 06/02/2023] [Indexed: 07/15/2023] Open
Abstract
Purpose Single-photon emission computed tomography (SPECT) is an important tool for myocardial perfusion imaging (MPI). Mechanical collimators cause the resolution-sensitivity trade-off in the existing cardiac SPECT systems, which hinders fast cardiac scan capability. In this work, we propose a novel collimator-less cardiac SPECT system with interspaced mosaic-patterned scintillators, aiming to significantly improve sensitivity and reduce scan time without trading-off image resolution. Methods We propose to assemble a collimator-less cardiac SPECT with 7 mosaic-patterned detector modules forming a half-ring geometry. The detector module consists of 10 blocks, each of which is assembled with 768 sparsely distributed scintillators with a size of 1.68 mm × 1.68 mm × 20 mm, forming a mosaic pattern in the trans-axial direction. Each scintillator bar contains 5 GAGG(Ce) scintillators and 5 optical-guide elements, forming a mosaic pattern in the axial direction. In the Monte Carlo simulations, the in-plane resolution and axial resolution are evaluated using a hot-rod phantom and 5 disk phantoms, respectively. We simulate a cardiac phantom that is placed in a water-filled cylinder and evaluate the image performance with different data acquisition time. We perform image reconstruction with the expectation-maximization algorithm using system matrices derived from the simulation of a uniform cylindrical source filling the field-of-view (FOV). Besides, a 2-D prototype system is designed to demonstrate the feasibility of the collimator-less imaging concept. Results In the simulation system, the sensitivity is 16.31% ± 8.85% in a 180 mm (Φ) × 100 mm (L) FOV. The 6-mm rods in the hot rod phantom and the 5-mm disks in the disk phantom are clearly separable. Satisfactory MPI image quality is achieved in the cardiac phantom study with an acquisition time of 30 s. In prototype experiments, the point sources with an 8 mm center-to-center distance are clearly separable at different positions across the FOV. Conclusion The study reveals a promising approach to high-sensitivity SPECT imaging without a heavy-metal collimator. In cardiac imaging, this approach opens the way to a very fast cardiac scan with good resolution. Further works are ongoing to build a practical 3-D imaging system based on the existing design.
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Affiliation(s)
- Rui Wang
- Department of Engineering Physics, Tsinghua University, Beijing, China
- Key Laboratory of Particle and Radiation Imaging, Ministry of Education (Tsinghua University), Beijing, China
- Institute for Precision Medicine, Tsinghua University, Beijing, China
| | - Debin Zhang
- Department of Engineering Physics, Tsinghua University, Beijing, China
- Key Laboratory of Particle and Radiation Imaging, Ministry of Education (Tsinghua University), Beijing, China
- Institute for Precision Medicine, Tsinghua University, Beijing, China
| | - Yifan Hu
- Department of Engineering Physics, Tsinghua University, Beijing, China
- Key Laboratory of Particle and Radiation Imaging, Ministry of Education (Tsinghua University), Beijing, China
- Institute for Precision Medicine, Tsinghua University, Beijing, China
| | - Zhenlei Lyu
- Department of Engineering Physics, Tsinghua University, Beijing, China
- Key Laboratory of Particle and Radiation Imaging, Ministry of Education (Tsinghua University), Beijing, China
- Institute for Precision Medicine, Tsinghua University, Beijing, China
| | - Tianyu Ma
- Department of Engineering Physics, Tsinghua University, Beijing, China
- Key Laboratory of Particle and Radiation Imaging, Ministry of Education (Tsinghua University), Beijing, China
- Institute for Precision Medicine, Tsinghua University, Beijing, China
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Strugari ME, DeBay DR, Beyea SD, Brewer KD. NEMA NU 1-2018 performance characterization and Monte Carlo model validation of the Cubresa Spark SiPM-based preclinical SPECT scanner. EJNMMI Phys 2023; 10:35. [PMID: 37261574 DOI: 10.1186/s40658-023-00555-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 05/15/2023] [Indexed: 06/02/2023] Open
Abstract
BACKGROUND The Cubresa Spark is a novel benchtop silicon-photomultiplier (SiPM)-based preclinical SPECT system. SiPMs in SPECT significantly improve resolution and reduce detector size compared to preclinical cameras with photomultiplier tubes requiring highly magnifying collimators. The NEMA NU 1 Standard for Performance Measurements of Gamma Cameras provides methods that can be readily applied or extended to characterize preclinical cameras with minor modifications. The primary objective of this study is to characterize the Spark according to the NEMA NU 1-2018 standard to gain insight into its nuclear medicine imaging capabilities. The secondary objective is to validate a GATE Monte Carlo simulation model of the Spark for use in preclinical SPECT studies. METHODS NEMA NU 1-2018 guidelines were applied to characterize the Spark's intrinsic, system, and tomographic performance with single- and multi-pinhole collimators. Phantoms were fabricated according to NEMA specifications with deviations involving high-resolution modifications. GATE was utilized to model the detector head with the single-pinhole collimator, and NEMA measurements were employed to tune and validate the model. Single-pinhole and multi-pinhole SPECT data were reconstructed with the Software for Tomographic Image Reconstruction and HiSPECT, respectively. RESULTS The limiting intrinsic resolution was measured as 0.85 mm owing to a high-resolution SiPM array combined with a 3 mm-thick scintillation crystal. The average limiting tomographic resolution was 1.37 mm and 1.19 mm for the single- and multi-pinhole collimators, respectively, which have magnification factors near unity at the center of rotation. The maximum observed count rate was 15,400 cps, and planar sensitivities of 34 cps/MBq and 150 cps/MBq were measured at the center of rotation for the single- and multi-pinhole collimators, respectively. All simulated tests agreed well with measurement, where the most considerable deviations were below 7%. CONCLUSIONS NEMA NU 1-2018 standards determined that a SiPM detector mitigates the need for highly magnifying pinhole collimators while preserving detailed information in projection images. Measured and simulated NEMA results were highly comparable with differences on the order of a few percent, confirming simulation accuracy and validating the GATE model. Of the collimators initially provided with the Spark, the multi-pinhole collimator offers high resolution and sensitivity for organ-specific imaging of small animals, and the single-pinhole collimator enables high-resolution whole-body imaging of small animals.
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Affiliation(s)
- Matthew E Strugari
- Biomedical Translational Imaging Centre, Halifax, NS, Canada.
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada.
| | - Drew R DeBay
- Biomedical Translational Imaging Centre, Halifax, NS, Canada
- Cubresa Inc., Winnipeg, MB, Canada
| | - Steven D Beyea
- Biomedical Translational Imaging Centre, Halifax, NS, Canada
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada
- Department of Diagnostic Radiology, Dalhousie University, Halifax, NS, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| | - Kimberly D Brewer
- Biomedical Translational Imaging Centre, Halifax, NS, Canada
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada
- Department of Diagnostic Radiology, Dalhousie University, Halifax, NS, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada
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Lee H, Cheon BW, Feld JW, Grogg K, Perl J, Ramos-Méndez JA, Faddegon B, Min CH, Paganetti H, Schuemann J. TOPAS-imaging: extensions to the TOPAS simulation toolkit for medical imaging systems. Phys Med Biol 2023; 68:10.1088/1361-6560/acc565. [PMID: 36930985 PMCID: PMC10164408 DOI: 10.1088/1361-6560/acc565] [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: 11/30/2022] [Accepted: 03/17/2023] [Indexed: 03/19/2023]
Abstract
Objective. The TOol for PArticle Simulation (TOPAS) is a Geant4-based Monte Carlo software application that has been used for both research and clinical studies in medical physics. So far, most users of TOPAS have focused on radiotherapy-related studies, such as modeling radiation therapy delivery systems or patient dose calculation. Here, we present the first set of TOPAS extensions to make it easier for TOPAS users to model medical imaging systems.Approach. We used the extension system of TOPAS to implement pre-built, user-configurable geometry components such as detectors (e.g. flat-panel and multi-planar detectors) for various imaging modalities and pre-built, user-configurable scorers for medical imaging systems (e.g. digitizer chain).Main results. We developed a flexible set of extensions that can be adapted to solve research questions for a variety of imaging modalities. We then utilized these extensions to model specific examples of cone-beam CT (CBCT), positron emission tomography (PET), and prompt gamma (PG) systems. The first of these new geometry components, the FlatImager, was used to model example CBCT and PG systems. Detected signals were accumulated in each detector pixel to obtain the intensity of x-rays penetrating objects or prompt gammas from proton-nuclear interaction. The second of these new geometry components, the RingImager, was used to model an example PET system. Positron-electron annihilation signals were recorded in crystals of the RingImager and coincidences were detected. The simulated data were processed using corresponding post-processing algorithms for each modality and obtained results in good agreement with the expected true signals or experimental measurement.Significance. The newly developed extension is a first step to making it easier for TOPAS users to build and simulate medical imaging systems. Together with existing TOPAS tools, this extension can help integrate medical imaging systems with radiotherapy simulations for image-guided radiotherapy.
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Affiliation(s)
- Hoyeon Lee
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America
| | - Bo-Wi Cheon
- Department of Radiation Convergence Engineering, Yonsei University, Wonju, Gangwon-do 26493, Republic of Korea
| | - Joseph W Feld
- Electrical Engineering and Computer Science Department, Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America
| | - Kira Grogg
- The Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America
| | - Joseph Perl
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025 United States of America
| | - José A Ramos-Méndez
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA 94115 United States of America
| | - Bruce Faddegon
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA 94115 United States of America
| | - Chul Hee Min
- Department of Radiation Convergence Engineering, Yonsei University, Wonju, Gangwon-do 26493, Republic of Korea
| | - Harald Paganetti
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America
| | - Jan Schuemann
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America
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Hnilicova P, Kantorova E, Sutovsky S, Grofik M, Zelenak K, Kurca E, Zilka N, Parvanovova P, Kolisek M. Imaging Methods Applicable in the Diagnostics of Alzheimer's Disease, Considering the Involvement of Insulin Resistance. Int J Mol Sci 2023; 24:3325. [PMID: 36834741 PMCID: PMC9958721 DOI: 10.3390/ijms24043325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 01/29/2023] [Accepted: 01/30/2023] [Indexed: 02/10/2023] Open
Abstract
Alzheimer's disease (AD) is an incurable neurodegenerative disease and the most frequently diagnosed type of dementia, characterized by (1) perturbed cerebral perfusion, vasculature, and cortical metabolism; (2) induced proinflammatory processes; and (3) the aggregation of amyloid beta and hyperphosphorylated Tau proteins. Subclinical AD changes are commonly detectable by using radiological and nuclear neuroimaging methods such as magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), and single-photon emission computed tomography (SPECT). Furthermore, other valuable modalities exist (in particular, structural volumetric, diffusion, perfusion, functional, and metabolic magnetic resonance methods) that can advance the diagnostic algorithm of AD and our understanding of its pathogenesis. Recently, new insights into AD pathoetiology revealed that deranged insulin homeostasis in the brain may play a role in the onset and progression of the disease. AD-related brain insulin resistance is closely linked to systemic insulin homeostasis disorders caused by pancreas and/or liver dysfunction. Indeed, in recent studies, linkages between the development and onset of AD and the liver and/or pancreas have been established. Aside from standard radiological and nuclear neuroimaging methods and clinically fewer common methods of magnetic resonance, this article also discusses the use of new suggestive non-neuronal imaging modalities to assess AD-associated structural changes in the liver and pancreas. Studying these changes might be of great clinical importance because of their possible involvement in AD pathogenesis during the prodromal phase of the disease.
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Affiliation(s)
- Petra Hnilicova
- Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
| | - Ema Kantorova
- Clinic of Neurology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
| | - Stanislav Sutovsky
- 1st Department of Neurology, Faculty of Medicine, Comenius University in Bratislava and University Hospital, 813 67 Bratislava, Slovakia
| | - Milan Grofik
- Clinic of Neurology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
| | - Kamil Zelenak
- Clinic of Radiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
| | - Egon Kurca
- Clinic of Neurology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
| | - Norbert Zilka
- Institute of Neuroimmunology, Slovak Academy of Sciences, 845 10 Bratislava, Slovakia
| | - Petra Parvanovova
- Department of Medical Biochemistry, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
| | - Martin Kolisek
- Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
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Parajuli RK, Sakai M, Parajuli R, Tashiro M. Development and Applications of Compton Camera-A Review. SENSORS (BASEL, SWITZERLAND) 2022; 22:7374. [PMID: 36236474 PMCID: PMC9573429 DOI: 10.3390/s22197374] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/08/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
The history of Compton cameras began with the detection of radiation sources originally for applications in astronomy. A Compton camera is a promising γ-ray detector that operates in the wide energy range of a few tens of keV to MeV. The γ-ray detection method of a Compton camera is based on Compton scattering kinematics, which is used to determine the direction and energy of the γ-rays without using a mechanical collimator. Although the Compton camera was originally designed for astrophysical applications, it was later applied in medical imaging as well. Moreover, its application in environmental radiation measurements is also under study. Although a few review papers regarding Compton cameras have been published, they either focus very specifically on the detectors used in such cameras or the particular applications of Compton cameras. Thus, the aim of this paper is to review the features and types of Compton cameras and introduce their applications, associated imaging algorithms, improvement scopes, and their future aspects.
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Affiliation(s)
- Raj Kumar Parajuli
- Department of Molecular Imaging and Theranostics, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan
- Gunma University Heavy Ion Medical Center, Gunma University, 3-39-22 Showa-machi, Maebashi 371-8511, Japan
| | - Makoto Sakai
- Gunma University Heavy Ion Medical Center, Gunma University, 3-39-22 Showa-machi, Maebashi 371-8511, Japan
| | | | - Mutsumi Tashiro
- Gunma University Heavy Ion Medical Center, Gunma University, 3-39-22 Showa-machi, Maebashi 371-8511, Japan
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Mathies F, Apostolova I, Dierck L, Jacobi J, Kuen K, Sauer M, Schenk M, Klutmann S, Forgács A, Buchert R. Multiple-pinhole collimators improve intra- and between-rater agreement and the certainty of the visual interpretation in dopamine transporter SPECT. EJNMMI Res 2022; 12:51. [PMID: 35976493 PMCID: PMC9385910 DOI: 10.1186/s13550-022-00923-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/08/2022] [Indexed: 11/10/2022] Open
Abstract
Background Multiple-pinhole (MPH) collimators improve the resolution–sensitivity trade-off compared to parallel-hole collimators. This study evaluated the impact of MPH collimators on intra- and between-rater agreement, and on the certainty of visual interpretation in dopamine transporter (DAT)-SPECT. Methods The study included 71 patients (62.1 ± 12.7 y). Two SPECT acquisitions were performed in randomized order after a single injection of 182 ± 9 MBq 123I-FP-CIT, one with MPH and one with low-energy–high-resolution–high-sensitivity (LEHRHS) collimators. MPH projections were reconstructed with an iterative 3d Monte Carlo algorithm. LEHRHS projections were reconstructed with filtered backprojection (FBP) or with ordered-subsets expectation–maximization and resolution recovery (OSEM). Images were visually evaluated twice by three independent raters with respect to presence/absence of Parkinson-typical reduction of striatal 123I-FP-CIT uptake using a Likert 6-score (− 3 = clearly normal, …, 3 = clearly reduced). In case of intra-rater discrepancy, an intra-rater consensus was obtained. Intra- and between-rater agreement with respect to the Likert score (6-score and dichotomized score) was characterized by Cohen’s kappa. Results Intra-rater kappa of visual scoring of MPH/LEHRHS-OSEM/LEHRHS-FBP images was 0.84 ± 0.12/0.73 ± 0.06/0.73 ± 0.08 (6-score, mean of three raters) and 1.00 ± 0.00/0.96 ± 0.04/0.97 ± 0.03 (dichotomized score). Between-rater kappa of visual scoring (intra-rater consensus) of MPH/LEHRHS-OSEM/LEHRHS-FBP images was 0.70 ± 0.06/0.63 ± 0.08/0.48 ± 0.05 (6-score, mean of three pairs of raters) and 1.00 ± 0.00/0.92 ± 0.04/0.90 ± 0.06 (dichotomized score). There was a decrease of (negative) Likert scores in normal DAT-SPECT by 0.87 ± 0.18 points from the LEHRHS-OSEM to the MPH setting. The (positive) Likert scores of reduced DAT-SPECT did not change on average. Conclusions MPH collimators improve intra- and between-rater agreement as well as the certainty of the visual interpretation of DAT-SPECT. Supplementary Information The online version contains supplementary material available at 10.1186/s13550-022-00923-w.
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Affiliation(s)
- Franziska Mathies
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Ivayla Apostolova
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Lena Dierck
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Janin Jacobi
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Katja Kuen
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Markus Sauer
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Michael Schenk
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Susanne Klutmann
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | | | - Ralph Buchert
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany.
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Lin PY, Jhan KJ, Ko KY, Yang CC. Investigating the lesion detectability of Tc-99m planar scintigraphy acquired with LEHRS collimator for patients with different body sizes: A phantom study. J Appl Clin Med Phys 2022; 23:e13744. [PMID: 35946828 PMCID: PMC9588265 DOI: 10.1002/acm2.13744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 07/11/2022] [Accepted: 07/13/2022] [Indexed: 11/25/2022] Open
Abstract
Purpose The aim of this work was to investigate the lesion detectability of Tc‐99m planar scintigraphy acquired with a low‐energy high‐resolution and sensitivity (LEHRS) collimator and processed by Clarity 2D for patients with different body sizes through phantom study. Methods A NEMA IEC body phantom set was covered by two layers of 25‐mm‐thick bolus to construct phantom in three different sizes. All image data were performed on a Discovery NM/CT 870 DR with an LEHRS collimator and processed by Clarity 2D with blend ratio a of 0%, 20%, 40%, 60%, 80%, and 100%. The lesion detectability in gamma scintigraphy was evaluated by calculating the contrast‐to‐noise ratio (CNR). Multiple linear regression methods were used to analyze the impact of body size, target size, and Clarity 2D blending weight on the lesion detectability of Tc‐99m planar scintigraphy. Results It was found that changing the blend ratio could improve CNR, and this phenomenon was more significant in anterior view than in posterior view. Our results also suggested that the blend ratio should be selected according to patient body size in order to maintain consistent CNR. Hence, when a blend ratio of 60% was used for a patient before cancer treatment, a lower blend ratio should be used for the same patient experiencing treatment‐related weight loss to achieve consistent lesion detectability in Tc‐99m planar scintigraphy acquired with LEHRS and processed by Clarity 2D. Conclusion The magnitude of photon attenuation and scattering is higher in patients with larger body size, so Tc‐99m planar scintigraphy usually has lower lesion detectability in obese patients. Although photon attenuation and scattering are inevitable during image formation, their impacts on image quality can be eased by employing appropriate image protocol parameters.
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Affiliation(s)
- Pei-Yao Lin
- Department of Nuclear Medicine, National Taiwan University Cancer Center, Taipei, Taiwan, ROC
| | - Kai-Jie Jhan
- Department of Nuclear Medicine, National Yang-Ming University Hospital, Yilan, Taiwan, ROC
| | - Kuan-Yin Ko
- Department of Nuclear Medicine, National Taiwan University Cancer Center, Taipei, Taiwan, ROC.,Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan. ROC
| | - Ching-Ching Yang
- Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC.,Department of Medical Research, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung, Taiwan, ROC
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Han DH, Lee SJ, Kim JO, Kwon DE, Lee HJ, Baek CH. Development of a diverging collimator for environmental radiation monitoring in the industrial fields. NUCLEAR ENGINEERING AND TECHNOLOGY 2022. [DOI: 10.1016/j.net.2022.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Tan Z, Wei H, Song X, Mai W, Yan J, Ye W, Ling X, Hou L, Zhang S, Yan S, Xu H, Wang L. Positron Emission Tomography in the Neuroimaging of Autism Spectrum Disorder: A Review. Front Neurosci 2022; 16:806876. [PMID: 35495051 PMCID: PMC9043810 DOI: 10.3389/fnins.2022.806876] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 03/14/2022] [Indexed: 12/11/2022] Open
Abstract
Autism spectrum disorder (ASD) is a basket term for neurodevelopmental disorders characterized by marked impairments in social interactions, repetitive and stereotypical behaviors, and restricted interests and activities. Subtypes include (A) disorders with known genetic abnormalities including fragile X syndrome, Rett syndrome, and tuberous sclerosis and (B) idiopathic ASD, conditions with unknown etiologies. Positron emission tomography (PET) is a molecular imaging technology that can be utilized in vivo for dynamic and quantitative research, and is a valuable tool for exploring pathophysiological mechanisms, evaluating therapeutic efficacy, and accelerating drug development in ASD. Recently, several imaging studies on ASD have been published and physiological changes during ASD progression was disclosed by PET. This paper reviews the specific radioligands for PET imaging of critical biomarkers in ASD, and summarizes and discusses the similar and different discoveries in outcomes of previous studies. It is of great importance to identify general physiological changes in cerebral glucose metabolism, cerebral blood flow perfusion, abnormalities in neurotransmitter systems, and inflammation in the central nervous system in ASD, which may provide excellent points for further ASD research.
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Affiliation(s)
- Zhiqiang Tan
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Huiyi Wei
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Xiubao Song
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
| | - Wangxiang Mai
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
| | - Jiajian Yan
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
| | - Weijian Ye
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Xueying Ling
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Lu Hou
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Shaojuan Zhang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Sen Yan
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, China
| | - Hao Xu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
- *Correspondence: Hao Xu,
| | - Lu Wang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
- Lu Wang,
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Do Y, Cho Y, Kang SH, Lee Y. Optimization of block-matching and 3D filtering (BM3D) algorithm in brain SPECT imaging using fan beam collimator: phantom study. NUCLEAR ENGINEERING AND TECHNOLOGY 2022. [DOI: 10.1016/j.net.2022.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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23
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Backer H, Bayerlein R, Binder T, Denker S, Fleck I, Peterson TE. Gamma-Ray Imaging Using Coincident Detection of Cherenkov Photons for Medical Applications. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2022. [DOI: 10.1109/trpms.2021.3101481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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24
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Dexter K, Foster J, Sosabowski J, Petrik M. Preclinical PET and SPECT Instrumentation. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00055-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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25
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Massari R, D’Elia A, Soluri A. Hybrid SPECT/CT. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00134-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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26
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Frangos S, Giannoula E, Exadaktylou P, Michael K, Iakovou I. Collimators for γ cameras. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00010-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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27
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Zannoni EM, Yang C, Meng LJ. Design Study of an Ultrahigh Resolution Brain SPECT System Using a Synthetic Compound-Eye Camera Design With Micro-Slit and Micro-Ring Apertures. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:3711-3727. [PMID: 34255626 PMCID: PMC8711775 DOI: 10.1109/tmi.2021.3096920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In this paper, we discuss the design study for a brain SPECT imaging system, referred to as the HelmetSPECT system, based on a spherical synthetic compound-eye (SCE) gamma camera design. The design utilizes a large number ( ∼ 500 ) of semiconductor detector modules, each coupled to an aperture with a very narrow opening for high-resolution SPECT imaging applications. In this study, we demonstrate that this novel system design could provide an excellent spatial resolution, a very high sensitivity, and a rich angular sampling without scanning motion over a clinically relevant field-of-view (FOV). These properties make the proposed HelmetSPECT system attractive for dynamic imaging of epileptic patients during seizures. In ictal SPECT, there is typically no prior information on where the seizures would happen, and both the imaging resolution and quantitative accuracy of the dynamic SPECT images would provide critical information for staging the seizures outbreak and refining the plans for subsequent surgical intervention.We report the performance evaluation and comparison among similar system geometries using non-conventional apertures, such as micro-ring and micro-slit, and traditional lofthole apertures. We demonstrate that the combination of ultrahigh-resolution imaging detectors, the SCE gamma camera design, and the micro-ring and micro-slit apertures would offer an interesting approach for the future ultrahigh-resolution clinical SPECT imaging systems without sacrificing system sensitivity and FOV.
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Könik A, Zeraatkar N, Kalluri KS, Auer B, Fromme TJ, He Y, May M, Furenlid LR, Kuo PH, King MA. Improved Performance of a Multipinhole SPECT for DAT Imaging by Increasing Number of Pinholes at the Expense of Increased Multiplexing. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2021; 5:817-825. [PMID: 34746540 DOI: 10.1109/trpms.2020.3035626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
SPECT imaging of dopamine transporters (DAT) in the brain is a widely utilized study to improve the diagnosis of Parkinsonian syndromes, where conventional (parallel-hole and fan-beam) collimators on dual-head scanners are commonly employed. We have designed a multi-pinhole (MPH) collimator to improve the performance of DAT imaging. The MPH collimator focuses on the striatum and hence offers a better trade-off for sensitivity and spatial resolution than the conventional collimators within this clinically most relevant region for DAT imaging. Our original MPH design consisted of 9 pinholes with a background-to-striatal (Bkg/Str) projection multiplexing of 1% only. In this simulation study, we investigated whether further improvements in the performance of MPH imaging could be obtained by increasing the number of pinholes, hence by enhancing the sensitivity and sampling, despite the ambiguity in reconstructing images due to increased multiplexing. We performed analytic simulations of the MPH configurations with 9, 13, and 16 pinholes (aperture diameters: 4-6mm) using a digital phantom modeling DAT imaging. Our quantitative analyses indicated that using 13 (Bkg/Str: 12%) and 16 (Bkg/Str: 22%) pinholes provided better performance than the original 9-pinhole configuration for the acquisition with 2 or 4 angular views, but a similar performance with 8 and 16 views.
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Affiliation(s)
- Arda Könik
- Department of Imaging, Dana Farber Cancer Institute, Boston, MA, 02215, USA
| | - Navid Zeraatkar
- Department of Radiology, Univ. of Mass. Medical School, Worcester, MA, 01605, USA
| | - Kesava S Kalluri
- Department of Radiology, Univ. of Mass. Medical School, Worcester, MA, 01605, USA
| | - Benjamin Auer
- Department of Radiology, Univ. of Mass. Medical School, Worcester, MA, 01605, USA
| | | | - Yulun He
- MD Anderson Cancer Center, Houston, TX
| | - Micaehla May
- Department of Radiology, University of Arizona, Tucson, AZ, 85724 USA
| | - Lars R Furenlid
- Department of Radiology, University of Arizona, Tucson, AZ, 85724 USA
| | - Phillip H Kuo
- Department of Radiology, University of Arizona, Tucson, AZ, 85724 USA
| | - Michael A King
- Department of Radiology, Univ. of Mass. Medical School, Worcester, MA, 01605, USA
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29
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Kiraga Ł, Kucharzewska P, Paisey S, Cheda Ł, Domańska A, Rogulski Z, Rygiel TP, Boffi A, Król M. Nuclear imaging for immune cell tracking in vivo – Comparison of various cell labeling methods and their application. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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30
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Ma T, Wei Q, Lyu Z, Zhang D, Zhang H, Wang R, Dong J, Liu Y, Yao R, He ZX. Self-Collimating SPECT With Multi-Layer Interspaced Mosaic Detectors. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:2152-2169. [PMID: 33852384 DOI: 10.1109/tmi.2021.3073288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Conventional single photon emission computed tomography (SPECT) relies on mechanical collimation whose resolution and sensitivity are interdependent, the best performance a SPECT system can attain is only a compromise of these two equally desired properties. To simultaneously achieve high resolution and sensitivity, we propose to use sensitive detectors constructed in a multi-layer in ter spaced mosaicdetectors (MATRICES) architecture to accomplish part of the collimation needed. We name this new approach self-collimation. We evaluate three self-collimating SPECT systems and report their imaging performance: 1) A simulated human brain SPECT achieves 3.88% sensitivity, it clearly resolves 0.5-mm and 1.0-mm hot-rod patterns at noise-free and realistic count-levels, respectively; 2) a simulated mouse SPECT achieves 1.25% sensitivity, it clearly resolves 50- [Formula: see text] and 100- [Formula: see text] hot-rod patterns at noise-free and realistic count-levels, respectively; 3) a SPECT prototype achieves 0.14% sensitivity and clearly separates 0.3-mm-diameter point sources of which the center-to-center neighbor distance is also 0.3 mm. Simulated contrast phantom studies show excellent resolution and signal-to-noise performance. The unprecedented system performance demonstrated by these 3 SPECT scanners is a clear manifestation of the superiority of the self-collimating approach over conventional mechanical collimation. It represents a potential paradigm shift in SPECT technology development.
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31
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Abstract
In this review, the roles of detectors in various medical imaging techniques were described. Ultrasound, optical (near-infrared spectroscopy and optical coherence tomography) and thermal imaging, magnetic resonance imaging, computed tomography, single-photon emission tomography, positron emission tomography were the imaging modalities considered. For each methodology, the state of the art of detectors mainly used in the systems was described, emphasizing new technologies applied.
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32
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Chaudhari AJ, Badawi RD. Application-specific nuclear medical in vivoimaging devices. Phys Med Biol 2021; 66. [PMID: 33770765 DOI: 10.1088/1361-6560/abf275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 03/26/2021] [Indexed: 11/11/2022]
Abstract
Nuclear medical imaging devices, such as those enabling photon emission imaging (gamma camera, single photon emission computed tomography, or positron emission imaging), that are typically used in today's clinics are optimized for assessing large portions of the human body, and are classified as whole-body imaging systems. These systems have known limitations for organ imaging, therefore application-specific devices have been designed, constructed and evaluated. These devices, given their compact nature and superior technical characteristics, such as their higher detection sensitivity and spatial resolution for organ imaging compared to whole-body imaging systems, have shown promise for niche applications. Several of these devices have further been integrated with complementary anatomical imaging devices. The objectives of this review article are to (1) provide an overview of such application-specific nuclear imaging devices that were developed over the past two decades (in the twenty-first century), with emphasis on brain, cardiac, breast, and prostate imaging; and (2) discuss the rationale, advantages and challenges associated with the translation of these devices for routine clinical imaging. Finally, a perspective on the future prospects for application-specific devices is provided, which is that sustained effort is required both to overcome design limitations which impact their utility (where these exist) and to collect the data required to define their clinical value.
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Affiliation(s)
- Abhijit J Chaudhari
- Department of Radiology, University of California Davis, Sacramento, CA 95817, United States of America.,Center for Molecular and Genomic Imaging, University of California Davis, Davis, CA 95616, United States of America
| | - Ramsey D Badawi
- Department of Radiology, University of California Davis, Sacramento, CA 95817, United States of America.,Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, United States of America
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33
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Gamma Camera Imaging with Rotating Multi-Pinhole Collimator. A Monte Carlo Feasibility Study. SENSORS 2021; 21:s21103367. [PMID: 34066113 PMCID: PMC8151746 DOI: 10.3390/s21103367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/06/2021] [Accepted: 05/11/2021] [Indexed: 11/24/2022]
Abstract
In this work, we propose and analyze a new concept of gamma ray imaging that corresponds to a gamma camera with a mobile collimator, which can be used in vivo, during surgical interventions for oncological patients for localizing regions of interest such as tumors or ganglia. The benefits are a much higher sensitivity, better image quality and, consequently, a dose reduction for the patient and medical staff. This novel approach is a practical solution to the overlapping problem which is inherent to multi-pinhole gamma camera imaging and single photon emission computed tomography and which translates into artifacts and/or image truncation in the final reconstructed image. The key concept consists in introducing a relative motion between the collimator and the detector. Moreover, this design could also be incorporated into most commercially available gamma camera devices, without any excessive additional requirements. We use Monte Carlo simulations to assess the feasibility of such a device, analyze three possible designs and compare their sensitivity, resolution and uniformity. We propose a final design of a gamma camera with a high sensitivity ranging from 0.001 to 0.006 cps/Bq, and a high resolution of 0.5–1.0 cm (FWHM), for source-to-detector distances of 4–10 cm. Additionally, this planar gamma camera provides information about the depth of source (with approximate resolution of 1.5 cm) and excellent image uniformity.
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34
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Zeraatkar N, Auer B, Kalluri KS, May M, Momsen NC, Richards RG, Furenlid LR, Kuo PH, King MA. Improvement in sampling and modulation of multiplexing with temporal shuttering of adaptable apertures in a brain-dedicated multi-pinhole SPECT system. Phys Med Biol 2021; 66:065004. [PMID: 33352545 PMCID: PMC9893699 DOI: 10.1088/1361-6560/abd5cd] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We are developing a multi-detector pinhole-based stationary brain-dedicated SPECT system: AdaptiSPECT-C. In this work, we introduced a new design prototype with multiple adaptable pinhole apertures for each detector to modulate the multiplexing by employing temporal shuttering of apertures. Temporal shuttering of apertures over the scan time provides the AdaptiSPECT-C with the capability of multiple-frame acquisition. We investigated, through analytic simulation, the impact of projection multiplexing on image quality using several digital phantoms and a customized anthropomorphic phantom emulating brain perfusion clinical distribution. The 105 pinholes in the collimator of the system were categorized into central, axial, and lateral apertures. We generated, through simulation, collimators of different multiplexing levels. Several data acquisition schemes were also created by changing the imaging time share of the acquisition frames. Sensitivity increased by 35% compared to the single-pinhole-per-detector base configuration of the AdaptiSPECT-C when using the central, axial, and lateral apertures with equal acquisition time shares within a triple-frame scheme with a high multiplexing scenario. Axial and angular sampling of the base configuration was enhanced by adding the axial and lateral apertures. We showed that the temporal shuttering of apertures can be exploited, trading the sensitivity, to modulate the multiplexing and to acquire a set of non-multiplexed non-truncated projections. Our results suggested that reconstruction benefited from utilizing both non-multiplexed projections and projections with modulated multiplexing resulting in a noticeably reduction in the multiplexing-induced image artefacts. Contrast recovery factor improved by 20% (9%) compared to the base configuration for a Defrise (hot-rod) phantom study when the central and axial (lateral) apertures with equal time shares were combined. The results revealed that, as an overall trend at each simulated multiplexing level, lowest normalized root-mean-square errors for the brain gray-matter regions were achieved with the combined usage of the central apertures and axial/lateral apertures.
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Affiliation(s)
- Navid Zeraatkar
- Department of Biomedical Engineering, University of California Davis, Davis, CA, USA, 95616.,Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA, 01655
| | - Benjamin Auer
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA, 01655
| | - Kesava S. Kalluri
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA, 01655
| | - Micaehla May
- James C. Wyant College of Optical Sciences, University of Arizona, Tucson, AZ, USA, 85721
| | - Neil C. Momsen
- James C. Wyant College of Optical Sciences, University of Arizona, Tucson, AZ, USA, 85721
| | - R. Garrett Richards
- James C. Wyant College of Optical Sciences, University of Arizona, Tucson, AZ, USA, 85721
| | - Lars R. Furenlid
- James C. Wyant College of Optical Sciences, University of Arizona, Tucson, AZ, USA, 85721.,Department of Medical Imaging, University of Arizona, Tucson, AZ, USA, 85724
| | - Phillip H. Kuo
- Department of Medical Imaging, University of Arizona, Tucson, AZ, USA, 85724
| | - Michael A. King
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA, 01655
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Guberman D, Paoletti R, Rugliancich A, Wunderlich C, Passeri A. Large-Area SiPM Pixels (LASiPs): A cost-effective solution towards compact large SPECT cameras. Phys Med 2021; 82:171-184. [PMID: 33640837 DOI: 10.1016/j.ejmp.2021.01.066] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/11/2020] [Accepted: 01/13/2021] [Indexed: 11/30/2022] Open
Abstract
Single Photon Emission Computed Tomography (SPECT) scanners based on photomultiplier tubes (PMTs) are still largely employed in the clinical environment. A standard camera for full-body SPECT employs ~50-100 PMTs of 4-8 cm diameter and is shielded by a thick layer of lead, becoming a heavy and bulky system that can weight a few hundred kilograms. The volume, weight and cost of a camera can be significantly reduced if the PMTs are replaced by silicon photomultipliers (SiPMs). The main obstacle to use SiPMs in full-body SPECT is the limited size of their sensitive area. A few thousand channels would be needed to fill a camera if using the largest commercially-available SiPMs of 6 × 6 mm2. As a solution, we propose to use Large-Area SiPM Pixels (LASiPs), built by summing individual currents of several SiPMs into a single output. We developed a LASiP prototype that has a sensitive area 8 times larger than a 6 × 6 mm2 SiPM. We built a proof-of-concept micro-camera consisting of a 40 × 40 × 8 mm3 NaI(Tl) crystal coupled to 4 LASiPs. We evaluated its performance in a central region of 15×15 mm2, where we were able to reconstruct images of a 99mTc capillary with an intrinsic spatial resolution of ~2 mm and an energy resolution of ~11.6% at 140 keV. We used these measurements to validate Geant4 simulations of the system. This can be extended to simulate a larger camera with more and larger pixels, which could be used to optimize the implementation of LASiPs in large SPECT cameras. We provide some guidelines towards this implementation.
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Affiliation(s)
- D Guberman
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Pisa, I-56126 Pisa, Italy; Dipartimento di Scienze Fisiche, della Terra e dell'Ambiente, Universitá di Siena, I-53100 Siena, Italy.
| | - R Paoletti
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Pisa, I-56126 Pisa, Italy; Dipartimento di Scienze Fisiche, della Terra e dell'Ambiente, Universitá di Siena, I-53100 Siena, Italy
| | - A Rugliancich
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Pisa, I-56126 Pisa, Italy
| | - C Wunderlich
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Pisa, I-56126 Pisa, Italy; Dipartimento di Scienze Fisiche, della Terra e dell'Ambiente, Universitá di Siena, I-53100 Siena, Italy
| | - A Passeri
- Dipartimento di Scienze Biomediche Sperimentali e Cliniche (SBSC), Universitá di Firenze, I-50134 Florence, Italy
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36
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Auer B, Zeraatkar N, Goding JC, Könik A, Fromme TJ, Kalluri KS, Furenlid LR, Kuo PH, King MA. Inclusion of quasi-vertex views in a brain-dedicated multi-pinhole SPECT system for improved imaging performance. Phys Med Biol 2021; 66:035007. [PMID: 33065564 PMCID: PMC9899040 DOI: 10.1088/1361-6560/abc22e] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
With brain-dedicated multi-detector systems employing pinhole apertures the usage of detectors facing the top of the patient's head (i.e. quasi-vertex (QV) views) can provide the advantage of additional viewing from close to the brain for improved detector coverage. In this paper, we report the results of simulation and reconstruction studies to investigate the impact of the QV views on the imaging performance of AdaptiSPECT-C, a brain-dedicated stationary SPECT system under development. In this design, both primary and scatter photons from regions located inferior to the brain can contribute to SPECT projections acquired by the QV views, and thus degrade AdaptiSPECT-C imaging performance. In this work, we determined the proportion, origin, and nature (i.e. primary, scatter, and multiple-scatter) of counts emitted from structures within the head and throughout the body contributing to projections from the different AdaptiSPECT-C detector rings, as well as from a true vertex view detector. We simulated phantoms used to assess different aspects of image quality (i.e. uniform activity concentration sphere, and Derenzo), as well as anthropomorphic phantoms with different count levels emulating clinical 123I activity distributions (i.e. DaTscan and perfusion). We determined that attenuation and scatter in the patient's body greatly diminish the probability of the photons emitted outside the volume of interest reaching to detectors and being recorded within the 15% photopeak energy window. In addition, we demonstrated that the inclusion of the residual of such counts in the system acquisition does not degrade visual interpretation or quantitative analysis. The addition of the QV detectors improves volumetric sensitivity, angular sampling, and spatial resolution leading to significant enhancement in image quality, especially in the striato-thalamic and superior regions of the brain. Besides, the use of QV detectors improves the recovery of clinically relevant metrics such as the striatal binding ratio and mean activity in selected cerebral structures. Our findings proving the usefulness of the QV ring for brain imaging with 123I agents can be generalized to other commonly used SPECT imaging agents labelled with isotopes, such as 99mTc and likely 111In.
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Affiliation(s)
- Benjamin Auer
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA, 01655
| | - Navid Zeraatkar
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA, 01655
| | - Justin C. Goding
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA, 01655
| | - Arda Könik
- Department of Imaging, Dana Farber Cancer Institute, Boston, MA, USA, 02215
| | | | - Kesava S. Kalluri
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA, 01655
| | - Lars R. Furenlid
- Wyant College of Optical Sciences, University of Arizona, Tucson, AZ, USA, 85721.,Department of Medical Imaging, University of Arizona, Tucson, AZ, USA, 85724
| | - Phillip H. Kuo
- Department of Medical Imaging, University of Arizona, Tucson, AZ, USA, 85724
| | - Michael A. King
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA, 01655
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37
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SPECT and SPECT/CT. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00008-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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38
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Yu H, Wang G. Compton-camera-based SPECT for thyroid cancer imaging. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2021; 29:111-124. [PMID: 33325449 DOI: 10.3233/xst-200769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Thyroid cancer is the most common type of endocrine-related cancer and the most common cancer in young women. Currently, single photon emission computed tomography (SPECT) and computed tomography (CT) are used with radioiodine scintigraphy to evaluate patients with thyroid cancer. The gamma camera for SPECT contains a mechanical collimator that greatly compromises dose efficiency and limits diagnostic sensitivity. Fortunately, the Compton camera is emerging as an ideal approach for mapping the distribution of radiopharmaceuticals inside the thyroid. In this preliminary study, based on the state-of-the-art readout chip Timepix3, we investigate the feasibility of using Compton camera for radiotracer SPECT imaging in thyroid cancer. A thyroid phantom is designed to mimic human neck, the mechanism of Compton camera-based event detection is simulated to generate realistic list-mode data, and a weighted back-projection method is developed to reconstruct the original distribution of the emission source. Study results show that the Compton camera can improve the detection efficiency for two or higher orders of magnitude comparing with the conventional gamma cameras. The thyroid gland regions can be reconstructed from the Compton camera measurements in terms of radiotracer distribution. This makes the Compton-camera-based SPECT imaging a promising modality for future clinical applications with significant benefits for dose reduction, scattering artifact reduction, temporal resolution enhancement, scan throughput increment, and others.
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Affiliation(s)
- Hengyong Yu
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, USA
| | - Ge Wang
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
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39
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Abstract
Respiratory motile cilia, specialized organelles of the cell, line the apical surface of epithelial cells lining the respiratory tract. By beating in a metachronal, synchronal fashion, these multiple, motile, actin-based organelles generate a cephalad fluid flow clearing the respiratory tract of inhaled pollutants and pathogens. With increasing environmental pollution, novel viral pathogens and emerging multi-drug resistant bacteria, cilia generated mucociliary clearance (MCC) is essential for maintaining lung health. MCC is also depressed in multiple congenital disorders like primary ciliary dyskinesia, cystic fibrosis as well as acquired disorders like chronic obstructive pulmonary disease. All these disorders have established, in some case multiple, mouse models. In this publication, we detail a method using a small amount of radioactivity and dual-modality SPECT/CT imaging to accurately and reproducibly measure MCC in mice in vivo. The method allows for recovery of mice after imaging, making serial measurements possible, and testing potential therapeutics longitudinally over time. The data in wild-type mice demonstrates the reproducibility of the MCC measurement as long as adequate attention to detail is paid, and the protocol strictly adhered to.
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Affiliation(s)
- Kyle S Feldman
- Department of Developmental Biology, University of Pittsburgh School of Medicine
| | - Maliha Zahid
- Department of Developmental Biology, University of Pittsburgh School of Medicine;
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40
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Zeraatkar N, Kalluri KS, Auer B, Konik A, Fromme TJ, Furenlid LR, Kuo PH, King MA. Investigation of Axial and Angular Sampling in Multi-Detector Pinhole-SPECT Brain Imaging. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:4209-4224. [PMID: 32763850 PMCID: PMC7875096 DOI: 10.1109/tmi.2020.3015079] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We designed a dedicated multi-detector multi-pinhole brain SPECT scanner to generate images of higher quality compared to general-purpose systems. The system, AdaptiSPECT-C, is intended to adapt its sensitivity-resolution trade-off by varying its aperture configurations allowing both high-sensitivity dynamic and high-spatial-resolution static imaging. The current system design consists of 23 detector heads arranged in a truncated spherical geometry. In this work, we investigated the axial and angular sampling capability of the current stationary system design. Two data acquisition schemes using limited rotation of the gantry and two others using axial translation of the imaging bed were also evaluated concerning their impact on image quality through improved sampling. Increasing both angular and axial sampling in the current prototype system resulted in quantitative improvements in image quality metrics and qualitative appearance of the images as determined in studies with specifically selected phantoms. Visual improvements for the brain phantoms with clinical distributions were less pronounced but presented quantitative improvements in the fidelity (normalized root-mean-square error (NRMSE)) and striatal specific binding ratio (SBR) for a dopamine transporter (DAT) distribution, and in NRMSE and activity recovery for a brain perfusion distribution. More pronounced improvements with increased sampling were seen in contrast recovery coefficient, bias, and coefficient of variation for a lesion in the brain perfusion distribution. The negligible impact of the most cranial ring of detectors on axial sampling, but its significant impact on sensitivity and angular sampling in the cranial portion of the imaging volume-of-interest were also determined.
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Dosimetry of tumor targeting imaging by convergent X-ray beam as compared with nuclear medicine. Appl Radiat Isot 2020; 167:109451. [PMID: 33059189 DOI: 10.1016/j.apradiso.2020.109451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/13/2020] [Accepted: 09/24/2020] [Indexed: 11/22/2022]
Abstract
During decades nuclear medicine procedures, based on radiolabeled agents, have proved to be efficient for diseases diagnosis and treatment. Radiation emerging from patient is detected aimed at localizing radiotracer distribution that is further correlated with biochemical/metabolic physiological processes. However, a significant drawback associated with current nuclear medicine procedures implementing radionuclide infusion regards to the inherent absorbed dose as well as radiopharmaceuticals' production, storage and elimination from patient body, thus representing a risk at patient and public health level. In the recent years, alternative methods have been proposed to reduce/eliminate radionuclides in some nuclear medicine procedures. The combination of high atomic number nanoparticles infused within patient body with incident X-ray beam, like tumor targeting and treatment, appears as a potential alternative method capable of theranostics. The process is based on inducing X-ray fluorescence and secondary electrons emission in high atomic number nanoparticles by means of excitation with an external X-ray beam, avoiding employing radioactive substances. The present work reports on the dosimetry performance of both methods, comparing whenever the external convergent X-ray beam alternative may involve less or larger radiation dose levels, according to comparable signal/image quality during the procedure. To this aim, a simplified theoretical model is proposed and associated Monte Carlo simulations are performed in order to compare typical case of nuclear medicine imaging with potential performance of an innovative method, called OXIRIS (Orthovoltage X-ray Induced Radiation and Integrated System), based on convergent X-ray beam exciting high atomic number nanoparticles infused in patient. The obtained results support the proposed alternative method's feasibility, once demonstrated that patient absorbed dose levels are relative similar to those currently used by nuclear medicine procedures, whereas dose to targeted region (tumor) are significantly higher, which may be useful for treatment purposes.
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Ozsahin I, Chen L, Könik A, King MA, Beekman FJ, Mok GSP. The clinical utilities of multi-pinhole single photon emission computed tomography. Quant Imaging Med Surg 2020; 10:2006-2029. [PMID: 33014732 PMCID: PMC7495312 DOI: 10.21037/qims-19-1036] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 07/30/2020] [Indexed: 11/06/2022]
Abstract
Single photon emission computed tomography (SPECT) is an important imaging modality for various applications in nuclear medicine. The use of multi-pinhole (MPH) collimators can provide superior resolution-sensitivity trade-off when imaging small field-of-view compared to conventional parallel-hole and fan-beam collimators. Besides the very successful application in small animal imaging, there has been a resurgence of the use of MPH collimators for clinical cardiac and brain studies, as well as other small field-of-view applications. This article reviews the basic principles of MPH collimators and introduces currently available and proposed clinical MPH SPECT systems.
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Affiliation(s)
- Ilker Ozsahin
- Biomedical Imaging Laboratory, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau, China
- Department of Biomedical Engineering, Faculty of Engineering, Near East University, Nicosia/TRNC, Mersin-10, Turkey
- DESAM Institute, Near East University, Nicosia/TRNC, Mersin-10, Turkey
| | - Ling Chen
- Biomedical Imaging Laboratory, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau, China
| | - Arda Könik
- Department of Imaging, Dana Farber Cancer Institute, Boston, MA, USA
| | - Michael A. King
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Freek J. Beekman
- Section of Biomedical Imaging, Department of Radiation Science and Technology, Delft University of Technology, Mekelweg 15, 2629 JB Delft, The Netherlands
- MILabs B.V, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands
| | - Greta S. P. Mok
- Biomedical Imaging Laboratory, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau, China
- Center for Cognitive and Brain Sciences, Institute of Collaborative Innovation, University of Macau, Macau, China
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Tecklenburg K, Forgács A, Apostolova I, Lehnert W, Klutmann S, Csirik J, Garutti E, Buchert R. Performance evaluation of a novel multi-pinhole collimator for dopamine transporter SPECT. Phys Med Biol 2020; 65:165015. [PMID: 32369781 DOI: 10.1088/1361-6560/ab9067] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
There is a tradeoff between spatial resolution and count sensitivity in SPECT with conventional collimators. Multi-pinhole (MPH) collimator technology has potential for concurrent improvement of resolution and sensitivity in clinical SPECT of 'small' organs. This study evaluated a novel MPH collimator specifically designed for dopamine transporter (DAT) SPECT with a triple-head SPECT camera. Count sensitivity was measured with a 99mTc point source placed on the lattice points of a 1 cm grid covering the whole field-of-view (FOV). Spatial resolution was assessed with a Derenzo type hot rod phantom. An anthropomorphic striatum phantom was scanned with total activity representative of a typical patient scan and different striatum-to-background activity concentration ratios. Recovery of striatum-to-background contrast was assessed by the contrast-recovery-coefficient. Measurements were repeated with double-head SPECT with fan-beam or low-energy-high-resolution-high-sensitivity (LEHRHS) collimators. A patient referred to DAT SPECT because of suspicion of Parkinson's disease was scanned with both LEHRHS and MPH collimators after a single tracer injection. The axial MPH sensitivity profile was approximately symmetrical around its peak, although it was shifted 7 cm towards the patient to simplify positioning. Peak sensitivity of the triple-head MPH system in the center of the FOV was 620 cps MBq-1 compared to 225 cps MBq-1 for the double-head fan-beam system. Sensitivity of the MPH system decreased towards the edges of the FOV. The full width of the sensitivity profile at 200 cps MBq-1 was 21 cm transaxially and 11 cm axially. In MPH SPECT of the Derenzo phantom all rods with ≥ 5 mm diameter were clearly visible. MPH SPECT improved striatal contrast recovery by ≥ 20% compared to fan-beam SPECT. The patient scan demonstrated good image quality of MPH SPECT with almost PET-like delineation of putamen and caudate nucleus. SPECT with dedicated MPH collimators provides considerable improvement of the resolution-sensitivity tradeoff in DAT SPECT compared to SPECT with fan-beam or LEHRHS collimators.
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Affiliation(s)
- K Tecklenburg
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Institute of Experimental Physics, Faculty of Mathematics, Informatics and Natural Sciences, University of Hamburg, Hamburg, Germany
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Van den Wyngaert T, Elvas F, De Schepper S, Kennedy JA, Israel O. SPECT/CT: Standing on the Shoulders of Giants, It Is Time to Reach for the Sky! J Nucl Med 2020; 61:1284-1291. [PMID: 32620702 DOI: 10.2967/jnumed.119.236943] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/28/2020] [Indexed: 12/11/2022] Open
Abstract
Twenty years ago, SPECT/CT became commercially available, combining the strengths of both techniques: the diagnostic sensitivity of SPECT and the anatomic detail of CT. Other benefits initially included attenuation correction of SPECT reconstructions, ultimately evolving to correction techniques that would enable absolute tracer uptake quantification. Recent developments in SPECT hardware include solid-state digital systems with higher sensitivity and resolution, using novel collimator designs based on tungsten. Similar advances in CT technology have been introduced in hybrid SPECT/CT systems, replacing low-end x-ray tubes with high-end multislice CT scanners equipped with iterative reconstruction, metal artifact reduction algorithms, and dual-energy capabilities. More recently, the design of whole-body SPECT/CT systems has taken another major leap with the introduction of a ring-shaped gantry equipped with multiple movable detectors surrounding the patient. These exciting developments have fueled efforts to develop novel SPECT radiopharmaceuticals, creating new chelators and prosthetic groups for radiolabeling. Innovative SPECT radionuclide pairs have now become available for radiolabeling with the potential for use as theranostic agents. The growth of precision medicine and the associated need for accurate radionuclide treatment dosimetry will likely drive the use of SPECT/CT in the near future. In addition, expanding clinical applications of SPECT/CT in other areas such as orthopedics offer exciting opportunities. Although it is true that the SPECT/CT ecosystem has seen several challenges during its development over the past 2 decades, it is now a feature-rich and mature tool ready for clinical prime time.
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Affiliation(s)
- Tim Van den Wyngaert
- Nuclear Medicine, Antwerp University Hospital, Edegem, Belgium .,Integrated Personalized and Precision Oncology Network, Faculty of Medicine and Health Sciences, University of Antwerp, Wilrijk, Belgium
| | - Filipe Elvas
- Nuclear Medicine, Antwerp University Hospital, Edegem, Belgium.,Integrated Personalized and Precision Oncology Network, Faculty of Medicine and Health Sciences, University of Antwerp, Wilrijk, Belgium
| | - Stijn De Schepper
- Nuclear Medicine, Antwerp University Hospital, Edegem, Belgium.,Integrated Personalized and Precision Oncology Network, Faculty of Medicine and Health Sciences, University of Antwerp, Wilrijk, Belgium
| | - John A Kennedy
- Department of Nuclear Medicine, Rambam Healthcare Campus, Haifa, Israel; and.,Rappaport School of Medicine, Israel Institute of Technology, Haifa, Israel
| | - Ora Israel
- Rappaport School of Medicine, Israel Institute of Technology, Haifa, Israel
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Carminati M, D'Adda I, Morahan AJ, Erlandsson K, Nagy K, Czeller M, Tolgyesi B, Nyitrai Z, Savi A, van Mullekom P, Hutton BF, Fiorini C. Clinical SiPM-Based MRI-Compatible SPECT: Preliminary Characterization. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2020. [DOI: 10.1109/trpms.2019.2951355] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Nakano T, Sakai M, Torikai K, Suzuki Y, Takeda S, Noda SE, Yamaguchi M, Nagao Y, Kikuchi M, Odaka H, Kamiya T, Kawachi N, Watanabe S, Arakawa K, Takahashi T. Imaging of 99mTc-DMSA and 18F-FDG in humans using a Si/CdTe Compton camera. ACTA ACUST UNITED AC 2020; 65:05LT01. [DOI: 10.1088/1361-6560/ab33d8] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Abstract
Molecular imaging enables both spatial and temporal understanding of the complex biologic systems underlying carcinogenesis and malignant spread. Single-photon emission tomography (SPECT) is a versatile nuclear imaging-based technique with ideal properties to study these processes in vivo in small animal models, as well as to identify potential drug candidates and characterize their antitumor action and potential adverse effects. Small animal SPECT and SPECT-CT (single-photon emission tomography combined with computer tomography) systems continue to evolve, as do the numerous SPECT radiopharmaceutical agents, allowing unprecedented sensitivity and quantitative molecular imaging capabilities. Several of these advances, their specific applications in oncology as well as new areas of exploration are highlighted in this chapter.
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Affiliation(s)
- Benjamin L Franc
- Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, H2232, MC 5281, Stanford, CA, 94305-5105, USA.
| | - Youngho Seo
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, USA
| | - Robert Flavell
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, USA
| | - Carina Mari Aparici
- Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, H2232, MC 5281, Stanford, CA, 94305-5105, USA
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Abstract
SPECT and PET are nuclear tomographic imaging modalities that visualize functional information based on the accumulation of radioactive tracer molecules. However, SPECT and PET lack anatomical information, which has motivated their combination with an anatomical imaging modality such as CT or MRI. This chapter begins with an overview over the fundamental physics of SPECT and PET followed by a presentation of the respective detector technologies, including detection requirements, principles and different detector concepts. The reader is subsequently provided with an introduction into hybrid imaging concepts, before a dedicated section presents the challenges that arise when hybridizing SPECT or PET with MRI, namely, mutual distortions of the different electromagnetic fields in MRI on the nuclear imaging system and vice versa. The chapter closes with an overview about current hybrid imaging systems of both clinical and preclinical kind. Finally, future developments in hybrid SPECT and PET technology are discussed.
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Affiliation(s)
- Teresa Nolte
- Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany
| | - Nicolas Gross-Weege
- Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany
| | - Volkmar Schulz
- Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany.
- Hyperion Hybrid Imaging Systems GmbH, Aachen, Germany.
- Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany.
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Könik A, Auer B, De Beenhouwer J, Kalluri K, Zeraatkar N, Furenlid LR, King MA. Primary, scatter, and penetration characterizations of parallel-hole and pinhole collimators for I-123 SPECT. Phys Med Biol 2019; 64:245001. [PMID: 31746783 DOI: 10.1088/1361-6560/ab58fe] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Multi-pinhole (MPH) collimators are known to provide better trade-off between sensitivity and resolution for preclinical, as well as for smaller regions in clinical SPECT imaging compared to conventional collimators. In addition to this geometric advantage, MPH plates typically offer better stopping power for penetration than the conventional collimators, which is especially relevant for I-123 imaging. The I-123 emits a series of high-energy (>300 keV, ~2.5% abundance) gamma photons in addition to the primary emission (159 keV, 83% abundance). Despite their low abundance, high-energy photons penetrate through a low-energy parallel-hole (LEHR) collimator much more readily than the 159 keV photons, resulting in large downscatter in the photopeak window. In this work, we investigate the primary, scatter, and penetration characteristics of a single pinhole collimator that is commonly used for I-123 thyroid imaging and our two MPH collimators designed for I-123 DaTscan imaging for Parkinson's Disease, in comparison to three different parallel-hole collimators through a series of experiments and Monte Carlo simulations. The simulations of a point source and a digital human phantom with DaTscan activity distribution showed that our MPH collimators provide superior count performance in terms of high primary counts, low penetration, and low scatter counts compared to the parallel-hole and single pinhole collimators. For example, total scatter, multiple scatter, and collimator penetration events for the LEHR were 2.5, 7.6 and 14 times more than that of MPH within the 15% photopeak window. The total scatter fraction for LEHR was 56% where the largest contribution came from the high-energy scatter from the back compartments (31%). For the same energy window, the total scatter for MPH was 21% with only 1% scatter from the back compartments. We therefore anticipate that using MPH collimators, higher quality reconstructions can be obtained in a substantially shorter acquisition time for I-123 DaTscan and thyroid imaging.
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Affiliation(s)
- Arda Könik
- Department of Imaging, Dana Farber Cancer Institute, Boston, MA 02215, United States of America
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A guide to 90Y radioembolization and its dosimetry. Phys Med 2019; 68:132-145. [DOI: 10.1016/j.ejmp.2019.09.236] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 09/15/2019] [Accepted: 09/17/2019] [Indexed: 01/14/2023] Open
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