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Demirtaş CK, Can M, Karadeniz Ö, Çilengiroğlu ÖV, Ertay T, Kaya GÇ. Energy window optimization in bremsstrahlung imaging after Yttrium-90 microsphere therapy. Biomed Phys Eng Express 2024; 10:025028. [PMID: 38306962 DOI: 10.1088/2057-1976/ad25ba] [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: 09/29/2023] [Accepted: 02/02/2024] [Indexed: 02/04/2024]
Abstract
In imaging of Yttrium-90 patients treated hepatic primary and metastatic cancers, bremsstrahlung photons produced in a wide energy range is used. However, the image quality depends on acquisition energy window. This research aimed energy window optimization for Yttrium-90 bremsstrahlung imaging and 48 patients with various types of cancer received radioembolization therapy were investigated. Patients were imaged using a GE Healthcare Optima NM/CT 640 series gamma camera system with a medium energy general-purpose (MEGP) collimator and planar images were acquired with 8 different energy windows in the 55-400 keV energy range. The data set, formed with the % FOV, contrast, and spatial resolution of image quality parameters calculated from these images, was statistically examined with ANOVA and Tukey tests. According to the visual evaluations and ANOVA/Tukey test results, it was statistically concluded that energy window of 90-110 keV is the optimal energy window while 60-400 keV energy ranges show the lowest image quality for Y-90 bremsstrahlung imaging.
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Affiliation(s)
- C Kayaş Demirtaş
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey
| | - M Can
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey
- Program of Nuclear Medicine Techniques, Vocational School of Health Services, Dokuz Eylül University, 35330, İnciralti, İzmir, Turkey
| | - Ö Karadeniz
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey
- Department of Physics, Faculty of Sciences, Dokuz Eylül University, 35390, Tınaztepe, Izmir, Turkey
| | - Ö Vupa Çilengiroğlu
- Department of Statistics, Faculty of Sciences, Dokuz Eylül University, 35390, Tınaztepe, Izmir, Turkey
| | - T Ertay
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey
- Department of Nuclear Medicine, Faculty of Medicine, Dokuz Eylül University, 35340, Inciraltı, Izmir, Turkey
| | - G Çapa Kaya
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey
- Department of Nuclear Medicine, Faculty of Medicine, Dokuz Eylül University, 35340, Inciraltı, Izmir, Turkey
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Gustafsson J, Taprogge J. Future trends for patient-specific dosimetry methodology in molecular radiotherapy. Phys Med 2023; 115:103165. [PMID: 37880071 DOI: 10.1016/j.ejmp.2023.103165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/03/2023] [Accepted: 10/17/2023] [Indexed: 10/27/2023] Open
Abstract
Molecular radiotherapy is rapidly expanding, and new radiotherapeutics are emerging. The majority of treatments is still performed using empirical fixed activities and not tailored for individual patients. Molecular radiotherapy dosimetry is often seen as a promising candidate that would allow personalisation of treatments as outcome should ultimately depend on the absorbed doses delivered and not the activities administered. The field of molecular radiotherapy dosimetry has made considerable progress towards the feasibility of routine clinical dosimetry with reasonably accurate absorbed-dose estimates for a range of molecular radiotherapy dosimetry applications. A range of challenges remain with respect to the accurate quantification, assessment of time-integrated activity and absorbed dose estimation. In this review, we summarise a range of technological and methodological advancements, mainly focussed on beta-emitting molecular radiotherapeutics, that aim to improve molecular radiotherapy dosimetry to achieve accurate, reproducible, and streamlined dosimetry. We describe how these new technologies can potentially improve the often time-consuming considered process of dosimetry and provide suggestions as to what further developments might be required.
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Affiliation(s)
| | - Jan Taprogge
- National Radiotherapy Trials Quality Assurance (RTTQA) Group, Joint Department of Physics, Royal Marsden NHSFT, Downs Road, Sutton SM2 5PT, United Kingdom; The Institute of Cancer Research, 123 Old Brompton Road, London SW7 3RP, United Kingdom
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Outcomes following transarterial radioembolization with 90Y and nanoparticles loaded resin microspheres. Appl Radiat Isot 2022; 188:110405. [PMID: 35987141 DOI: 10.1016/j.apradiso.2022.110405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 06/26/2022] [Accepted: 08/04/2022] [Indexed: 11/21/2022]
Abstract
90Y bremsstrahlung Single-Photon Emission Tomography (SPECT) imaging is employed to check the possibility of extrahepatic uptake and the quantification of delivered dose in Transarterial Radioembolization (TARE). 90Y bremsstrahlung SPECT imaging is challenging due to the nature of bremsstrahlung photons. We reported a Monte Carlo study using the resin microspheres loaded with 90Y and Nanoparticles (NPs) in the TARE. By injection of Bismuth (Bi) and Europium (Eu) NPs into the resin microspheres, the sensitivity and the contrast to noise ratio increased for the bremsstrahlung planar images. The highest signal to background ratio was observed in the characteristic X-ray planar images taken with the energy window at the Kα1 ± 10 keV when Eu NPs were incorporated into the microsphere. The dose enhancement ratio decreased dramatically at NP concentrations >2.4 M. Incorporating NPs into the resin microspheres improves the quality of post-treatment images and establishes a standardized imaging protocol for post-treatment imaging by characteristic X-rays.
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Role of nanoparticles in transarterial radioembolization with glass microspheres. Ann Nucl Med 2022; 36:479-487. [PMID: 35199286 DOI: 10.1007/s12149-022-01727-7] [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: 09/21/2021] [Accepted: 02/06/2022] [Indexed: 11/01/2022]
Abstract
OBJECTIVE Transarterial Radioembolization (TARE) with 90Y-loaded glass microspheres is a locoregional treatment option for Hepatocellular Carcinoma (HCC). Post-treatment 90Y bremsstrahlung imaging using Single-Photon Emission Tomography (SPECT) is currently a gold-standard imaging modality for quantifying the delivered dose. However, the nature of bremsstrahlung photons causes difficulty for dose estimation using SPECT imaging. This work aimed to investigate the possibility of using glass microspheres loaded with 90Y and Nanoparticles (NPs) to improve the quantification of delivered doses. METHODS The Monte Carlo codes were used to simulate the post-TARE 90Y planar imaging. Planar images from bremsstrahlung photons and characteristic X-rays are acquired when 0, 1.2 mol/L, 2.4 mol/L, and 4.8 mol/L of Gold (Au), Hafnium (Hf), and Gadolinium (Gd) NPs are incorporated into the glass microspheres. We evaluated the quality of acquired images by calculating sensitivity and Signal-to-Background Ratio (SBR). Therapeutic effects of NPs were evaluated by calculation of Dose Enhancement Ratio (DER) in tumoral and non-tumoral liver tissues. RESULTS The in silico results showed that the sensitivity values of bremsstrahlung and characteristic X-ray planar images increased significantly as the NPs concentration increased in the glass microspheres. The SBR values decreased as the NPs concentration increased for the bremsstrahlung planar images. In contrast, the SBR values increased for the characteristic X-ray planar images when Hf and Gd were incorporated into the glass microspheres. The DER values decreased in the tumoral and non-tumoral liver tissues as the NPs concentration increased. The maximum dose reduction was observed at the NPs concentration of 4.8 mol/L (≈ 7%). CONCLUSIONS The incorporation of Au, Hf, and Gd NPs into the glass microspheres improved the quality and quantity of post-TARE planar images. Also, treatment efficiency was decreased significantly at NPs concentration > 4.8 mol/L.
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Auditore L, Pistone D, Amato E, Italiano A. Monte Carlo methods in nuclear medicine. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00136-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Oral A, Guvenis A. Improving the detectability of overactive glands in dual-phase parathyroid SPECT/CT: a Monte Carlo simulation study. Biomed Phys Eng Express 2021; 7. [PMID: 34102614 DOI: 10.1088/2057-1976/ac0954] [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: 01/25/2021] [Accepted: 06/08/2021] [Indexed: 11/11/2022]
Abstract
Objective. SPECT-CT is a standard procedure conducted before minimally invasive surgery for the treatment of primary hyperthyroidism. In order to improve image quality, it is important to know how defect detectability is influenced by acquisition and processing parameters. The objective of this study is to continue prior physical phantom optimization studies by performing Monte Carlo simulations for the dual phase parathyroid SPECT-CT protocol using a digital anthropomorphic phantom.Methods. The dual phase parathyroid SPECT-CT imaging procedure with 99mTc-Sestamibi was simulated using the previously extensively validated SIMIND software for the first time. An anthropomorphic ZUBAL based phantom was built to represent an adenoma. Its diameter was set to 0.76 cm which corresponded to more than three times the pixel size and the target-to-background ratio was set to 16:1 based on previous studies. Four different collimators were tested. Contrast-to-noise (CNR) values were determined for different scatter correction options and processing parameter values. The OSEM algorithm was used for image reconstruction.Results. CNR values were improved from about zero (LEGP collimator, 16 iterations, attenuation correction: on, scatter correction: off) up to 3.7 (LEUHR collimator, 16 iterations, attenuation correction: on, scatter correction: off). The subjective visual assessment of detectability on simulated images agreed with the quantitative CNR values.Conclusion. Higher resolution collimators gave better CNR as confirmed by similar studies. The effect of scatter correction was found beneficial only if both the resolution and sensitivity of the collimator were relatively high. This is a significant finding since there is a shortage of definitive guideline on the use of scatter correction for parathyroid SPECT imaging.
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Affiliation(s)
- Aysegul Oral
- Institute of Biomedical Engineering, Bogazici University, Kandilli Kampus, Cengelkoy, 34684 Istanbul, Turkey
| | - Albert Guvenis
- Institute of Biomedical Engineering, Bogazici University, Kandilli Kampus, Cengelkoy, 34684 Istanbul, Turkey
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Pastrana Orejuela CO, de Assis Coelho F, Oliveira SM, Souza SAL, Vasconcellos de Sá L, Xavier da Silva A, Torres Berdeguez MB. SPECT performance evaluation on image of Yttrium 90 - Bremsstrahlung using Monte Carlo simulation. Appl Radiat Isot 2020; 168:109456. [PMID: 33321371 DOI: 10.1016/j.apradiso.2020.109456] [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: 12/31/2019] [Revised: 09/16/2020] [Accepted: 09/30/2020] [Indexed: 11/15/2022]
Abstract
Yttrium-90 (90Y) is one of the most widely used radionuclides in Nuclear Medicine practice. However, characteristic energy of this beta emitter constitutes a difficulty for dose planning using SPECT imaging. This work aimed to study bremsstrahlung X-rays effects produced by 90Y beta particles during SPECT image acquisition using Monte Carlo code MCNPX. Several simulations were carried out to evaluate different aspects that could affect SPECT image quality, such as: collimator type, source-collimator distance and composition of each interacting material. Two configurations of 90Y sources were simulated: a point source in several spheres of different materials (soft tissue, water, articular cartilage, and bone) and dimensions with radius ranging from 1 to 20 mm; and a uniformly distributed source in a Lucite cylindrical phantom filled with water. It was evaluated the bremsstrahlung photon emission generated inside different materials; for this was considered the number photons that passing through every different sphere's surface for each radii and material. In case of cylindrical phantom filled with water, in order to obtain the energy deposited over NaI (Tl) crystal detector; there was considered Median Energy General Purpose (MEGP) and Low Energy High Resolution (LEHR) collimators. Moreover, using TMESH routine available in the MCNPX Monte Carlo code, energy distribution images according to the collimator type and the source-collimator distance were obtained. The simulation was validated by comparing with the spectral distribution of the 90Y bremsstrahlung X-rays obtained experimentally from an acrylic cylindrical phantom. Results corroborated the importance of Monte Carlo simulation method to evaluate a performance of SPECT image acquisition with 90Y. The best resolution was obtained with MEGP collimator independent of source-collimator distance.
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Affiliation(s)
| | - Francisco de Assis Coelho
- Department of Nuclear Medicine, Clementino Fraga Filho University Hospital, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
| | - Susie Medeiros Oliveira
- Department of Nuclear Medicine, Clementino Fraga Filho University Hospital, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
| | - Sergio A L Souza
- Department of Nuclear Medicine, Clementino Fraga Filho University Hospital, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
| | - Lidia Vasconcellos de Sá
- Institute of Radiation Protection and Dosimetry, Brazilian Nuclear Energy Commission, Rio de Janeiro, RJ, Brazil.
| | - Ademir Xavier da Silva
- Department of Nuclear Engineering, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
| | - Mirta B Torres Berdeguez
- Department of Nuclear Engineering, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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Ouahman M, Errifai R, Asmi H, Bouzekraoui Y, Douama S, Bentayeb F, Bonutti F. Collimator and Energy Window Evaluation in Ga-67 Imaging by Monte Carlo Simulation. Mol Imaging Radionucl Ther 2020; 29:118-123. [PMID: 33094575 PMCID: PMC7583743 DOI: 10.4274/mirt.galenos.2020.21549] [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] [Indexed: 12/01/2022] Open
Abstract
Objectives: Gallium-67 (Ga-67) imaging is affected by collimator penetration and scatter components owing to the high-energy (HE) gamma-ray emissions. The characterization of penetration and scatter distribution is essential for the optimization of low-energy high-resolution (LEHR), medium energy (ME), and HE collimators and for the development of an effective correction technique. We compared the image quality that can be achieved by 3 collimators for different energy windows using the SIMIND Monte Carlo code. Methods: Simulation experiments were conducted for LEHR, ME, and HE collimators for Ga-67 point source placed at 12-cm distance from the detector surface using the Monte Carlo SIMIND simulation code. Their spectra point spread functions as well as the original, penetration, scattering, and X-rays curves were drawn and analyzed. The parameters full-width at half maximum and full-width at tenth maximum were also investigated. Results: The original, penetration, and scatter curves within 10% for LEHR were 34.46%, 33.52%, 17.29%, and 14.72%, respectively. Similarly, the original, penetration, scatter, and X-rays within 10% for ME and HE were 83.06%, 10.25%, 6.69%, and 0% and 81.44%, 11.51%, 7.05%, and 0%, respectively. The trade-off between spatial resolution and sensitivity was achieved by using the ME collimator at 185 photopeak of Ga-67. Conclusion: The Monte Carlo simulation outcomes can be applied for optimal collimator designing and for the development of new correction method in Ga-67 imaging.
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Affiliation(s)
- Mina Ouahman
- Mohammed V-Rabat University Faculty of Science, Laboratory of High Energy Physics Modelisation Simulation, Rabat, Morocco
| | - Rachid Errifai
- Mohammed V-Rabat University Faculty of Science, Laboratory of High Energy Physics Modelisation Simulation, Rabat, Morocco
| | - Hicham Asmi
- Mohammed V-Rabat University Faculty of Science, Laboratory of High Energy Physics Modelisation Simulation, Rabat, Morocco
| | - Youssef Bouzekraoui
- Mohammed V-Rabat University Faculty of Science, Laboratory of High Energy Physics Modelisation Simulation, Rabat, Morocco
| | - Sanae Douama
- Mohammed V-Rabat University Faculty of Science, Laboratory of High Energy Physics Modelisation Simulation, Rabat, Morocco
| | - Farida Bentayeb
- Mohammed V-Rabat University Faculty of Science, Laboratory of High Energy Physics Modelisation Simulation, Rabat, Morocco
| | - Faustino Bonutti
- Academic Hospital of Udine, Clinic of Medical Physics, Udine, Italy
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İnce C, Karadeniz Ö, Ertay T, Durak H. Collimator and energy window optimization for YTTRIUM-90 bremsstrahlung SPECT imaging. Appl Radiat Isot 2020; 167:109453. [PMID: 33039763 DOI: 10.1016/j.apradiso.2020.109453] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/01/2020] [Accepted: 09/25/2020] [Indexed: 10/23/2022]
Abstract
The optimal collimator and energy window for Yttrium-90 bremsstrahlung SPECT imaging was investigated in the study. Yttrium-90 images were acquired with a dual-head gamma camera, equipped with parallel hole collimators and 90Y vial for different energy windows ranging from 56 to 232 keV. Image quality parameters (sensitivity, %FOV, and S/B) were examined for the energy window and collimator combinations. It is concluded that the optimal SPECT imaging was achieved using FBP Method with a HEGP collimator and the energy window of 90-110 keV.
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Affiliation(s)
- Caner İnce
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey
| | - Özlem Karadeniz
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey; Department of Physics, Faculty of Sciences, Dokuz Eylül University, 35390, Tınaztepe, İzmir, Turkey.
| | - Türkan Ertay
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey; Department of Nuclear Medicine, Faculty of Medicine, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey
| | - Hatice Durak
- Department of Medical Physics, Institute of Health Sciences, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey; Department of Nuclear Medicine, Faculty of Medicine, Dokuz Eylül University, 35340, İnciraltı, İzmir, Turkey
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Effect of ME Collimator Characteristic, Energy Window Width, and Reconstruction Algorithm Selection on Imaging Performance of Yttrium-90: Simulation Study. Nucl Med Mol Imaging 2019; 53:414-422. [DOI: 10.1007/s13139-019-00619-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 09/24/2019] [Accepted: 10/17/2019] [Indexed: 10/25/2022] Open
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Bouzekraoui Y, Bentayeb F, Asmi H, Bonutti F. Comparison of Image Quality of Different Radionuclides Technetium-99m, Samarium-153, and Iodine-123. Indian J Nucl Med 2019; 34:201-204. [PMID: 31293298 PMCID: PMC6593946 DOI: 10.4103/ijnm.ijnm_42_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Introduction: The choice of the radionuclide has a key role in nuclear medicine which appearing the lowest scatter fraction. In addition, the presence of penetrated and scattered photons from collimator in single-photon emission computed tomography images degrades resolution and contrast. Thus, image quality depends on sensitivity and resolution of the collimator–detector system. The goal of this study was to compare the image quality that can be achieved by three radionuclides: technetium-99 m (Tc-99 m), iodine-123 (I-123), and samarium-153 (Sm-153). Materials and Methods: Tc-99 m and Sm-153 were imaged with low-energy high resolution (LEHR) collimator, while I-123 was imaged with medium-energy (ME) collimator. We modeled the Siemens Symbia Medical system using Monte Carlo simulation code SIMIND. The imaging characteristics of each radionuclide were investigated by simulated data: point spread function, sensitivity (Cps/MBq) and geometric, penetration and scattering distribution. Results: Tc-99 m and Sm-153 give best and results with LEHR collimator for spatial resolution (full width at half maximum [FWHM] = 3.19 mm; full width at tenth maximum [FWTM] = 6.73 mm) and (FWHM = 3.22 mm; FWTM = 7.39 mm), respectively. Whereas, I-123 provided with ME collimator a lower resolution (FWHM = 4.89 mm; FWTM = 9.89 mm). The sensitivity recorded by Tc-99 m, Sm-153, and I-153 were (31.21 Cps/MBq), (10.16 Cps/MBq), and (51.22 Cps/MBq), respectively. Conclusion: Tc-99 m and Sm-153 give the best and generally similar imaging properties with LEHR. For I-123, the ME collimator helps lowering the influence of high-energy gamma rays.
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Affiliation(s)
- Youssef Bouzekraoui
- Department of Physics, LPHE, Modeling and Simulations, Faculty of Science, Mohammed V University, Rabat, Morocco
| | - Farida Bentayeb
- Department of Physics, LPHE, Modeling and Simulations, Faculty of Science, Mohammed V University, Rabat, Morocco
| | - Hicham Asmi
- Department of Physics, LPHE, Modeling and Simulations, Faculty of Science, Mohammed V University, Rabat, Morocco
| | - Faustino Bonutti
- Department of Medical Physics, Academic Hospital of Udine, Udine, Italy
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Effects of collimator on imaging performance of Yttrium-90 Bremsstrahlung photons: Monte Carlo simulation. NUCLEAR ENGINEERING AND TECHNOLOGY 2019. [DOI: 10.1016/j.net.2018.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Calculation of productions of medical 201Pb, 198Au, 186Re, 111Ag, 103Pd, 90Y, 89Sr, 77Kr, 77As, 67Cu, 64Cu, 47Sc and 32P nuclei used in cancer therapy via phenomenological and microscopic level density models. Appl Radiat Isot 2019; 144:64-79. [DOI: 10.1016/j.apradiso.2018.11.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 10/12/2018] [Accepted: 11/22/2018] [Indexed: 11/24/2022]
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Bouzekraoui Y, Bentayeb F, Asmi H, Bonutti F. Energy Window and Contrast Optimization for Single-photon Emission Computed Tomography Bremsstrahlung Imaging with Yttrium-90. Indian J Nucl Med 2019; 34:125-128. [PMID: 31040523 PMCID: PMC6481209 DOI: 10.4103/ijnm.ijnm_150_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Purpose In yttrium-90 (Y-90) single-photon emission computed tomography (SPECT) imaging, the choice of the acquisition energy window is not trivial, due to the continuous and broad energy distribution of the bremsstrahlung photons. In this work, we investigate the effects of the energy windows on the image contrast to noise ratio (CNR), in order to select the optimal energy window for Y-90 imaging. Materials and Methods We used the Monte Carlo SIMIND code to simulate the Jaszczak phantom which consists of the six hot spheres filled with Y-90 and ranging from 9.5 to 31.8 mm in diameter. Siemens Symbia gamma camera fitted with a high-energy collimator was simulated. To evaluate the effect of the energy windows on the image contrast, five narrow and large energy windows were assessed. Results The optimal energy window obtained for Y-90 bremsstrahlung SPECT imaging was 120-150 keV. Furthermore, the results obtained for CNR indicate that the high detection is only for the three large spheres. Conclusion The optimization of energy window in Y-90 bremsstrahlung has the potential to improve the image quality.
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Affiliation(s)
- Youssef Bouzekraoui
- Department of Physics, LPHE, Modeling and Simulations, Faculty of Science, Mohammed V University, Rabat, Morocco
| | - Farida Bentayeb
- Department of Physics, LPHE, Modeling and Simulations, Faculty of Science, Mohammed V University, Rabat, Morocco
| | - Hicham Asmi
- Department of Physics, LPHE, Modeling and Simulations, Faculty of Science, Mohammed V University, Rabat, Morocco
| | - Faustino Bonutti
- Department of Medical Physics, Academic Hospital of Udine, Udine, Italy
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Sarrut D, Krah N, Badel JN, Létang JM. Learning SPECT detector angular response function with neural network for accelerating Monte-Carlo simulations. ACTA ACUST UNITED AC 2018; 63:205013. [DOI: 10.1088/1361-6560/aae331] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abbaspour S, Tanha K, Mahmoudian B, Assadi M, Pirayesh Islamian J. A Monte Carlo study on the performance evaluation of a parallel hole collimator for a HiReSPECT: A dedicated small-animal SPECT. Appl Radiat Isot 2018; 139:53-60. [PMID: 29704706 DOI: 10.1016/j.apradiso.2018.04.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 04/07/2018] [Accepted: 04/16/2018] [Indexed: 11/16/2022]
Abstract
Collimator geometry has an important contribution on the image quality in SPECT imaging. The purpose of this study was to investigate the effect of parallel hole collimator hole-size on the functional parameters (including the spatial resolution and sensitivity) and the image quality of a HiReSPECT imaging system using SIMIND Monte Carlo program. To find a proper trade-off between the sensitivity and spatial resolution, the collimator with hole diameter ranges of 0.3-1.5 mm (in steps of 0.3 mm) were used with a fixed septal and hole thickness values (0.2 mm and 34 mm, respectively). Lead, Gold, and Tungsten as the LEHR collimator material were also investigated. The results on a 99mTc point source scanning with the experimental and also simulated systems were matched to validate the simulated imaging system. The results on the simulation showed that decreasing the collimator hole size, especially in the Gold collimator, improved the spatial resolution to 18% and 3.2% compared to the Lead and the Tungsten, respectively. Meanwhile, the Lead collimator provided a good sensitivity in about of 7% and 8% better than that of Tungsten and Gold, respectively. Overall, the spatial resolution and sensitivity showed small differences among the three types of collimator materials assayed within the defined energy. By increasing the hole size, the Gold collimator produced lower scatter and penetration fractions than Tungsten and Lead collimator. The minimum detectable size of hot rods in micro-Jaszczak phantom on the iterative maximum-likelihood expectation maximization (MLEM) reconstructed images, were determined in the sectors of 1.6, 1.8, 2.0, 2.4 and 2.6 mm for scanning with the collimators in hole sizes of 0.3, 0.6, 0.9, 1.2 and 1.5 mm at a 5 cm distance from the phantom. The Gold collimator with hole size of 0.3 mm provided a better image quality with the HiReSPECT imaging.
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Affiliation(s)
- Samira Abbaspour
- Department of Radiotherapy, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Kaveh Tanha
- The Persian Gulf Nuclear Medicine Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Babak Mahmoudian
- Department of Radiology, Radiotherapy and Nuclear Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Majid Assadi
- The Persian Gulf Nuclear Medicine Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Jalil Pirayesh Islamian
- Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Attar Neyshaburi St, Azadi Ave, Tabriz 5166614766, Iran.
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