Pub Date : 2025-07-10DOI: 10.1109/TRPMS.2025.3581330
{"title":"IEEE Transactions on Radiation and Plasma Medical Sciences Publication Information","authors":"","doi":"10.1109/TRPMS.2025.3581330","DOIUrl":"https://doi.org/10.1109/TRPMS.2025.3581330","url":null,"abstract":"","PeriodicalId":46807,"journal":{"name":"IEEE Transactions on Radiation and Plasma Medical Sciences","volume":"9 6","pages":"C2-C2"},"PeriodicalIF":4.6,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11075576","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144597951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-10DOI: 10.1109/TRPMS.2025.3581328
{"title":"IEEE Transactions on Radiation and Plasma Medical Sciences Information for Authors","authors":"","doi":"10.1109/TRPMS.2025.3581328","DOIUrl":"https://doi.org/10.1109/TRPMS.2025.3581328","url":null,"abstract":"","PeriodicalId":46807,"journal":{"name":"IEEE Transactions on Radiation and Plasma Medical Sciences","volume":"9 6","pages":"C3-C3"},"PeriodicalIF":4.6,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11075579","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144597950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-30DOI: 10.1109/TRPMS.2025.3582528
Wenjun Xia;Chuang Niu;Grigorios M. Karageorgos;Jiayong Zhang;Nils Peters;Harald Paganetti;Bruno De Man;Ge Wang
In computed tomography (CT), the presence of metal parts in the scanned region results in metal artifacts in the reconstructed images, which can significantly impact diagnosis and treatment planning. Consequently, removing metal artifacts has been a critical area of research in clinical practice. In this article, we propose a metal artifact reduction (MAR) algorithm based on dual-domain denoising diffusion probabilistic models (DDPMs). Our approach begins with preprocessing with linear interpolation (LI) and refinement with a convolutional neural network (CNN) to generate an initial reprojection. Then, two DDPM networks are employed: one to synthesize the corrupted sinogram and the other to optimize the resultant images in the image domain. The experimental results show that our algorithm utilizes two specialized DDPMs and achieves superior performance. The sinogram-domain DDPM reconstructs a high-quality sinogram, while the image-domain DDPM effectively removes remaining artifacts. Synergistically, these contributions lead to a significant improvement in overall image quality. Furthermore, our method successfully addresses the hallucination issues observed in the generic DDPM, enhancing the applicability of DDPM in medical imaging.
{"title":"Dual-Domain Denoising Diffusion Probabilistic Model for Metal Artifact Reduction","authors":"Wenjun Xia;Chuang Niu;Grigorios M. Karageorgos;Jiayong Zhang;Nils Peters;Harald Paganetti;Bruno De Man;Ge Wang","doi":"10.1109/TRPMS.2025.3582528","DOIUrl":"https://doi.org/10.1109/TRPMS.2025.3582528","url":null,"abstract":"In computed tomography (CT), the presence of metal parts in the scanned region results in metal artifacts in the reconstructed images, which can significantly impact diagnosis and treatment planning. Consequently, removing metal artifacts has been a critical area of research in clinical practice. In this article, we propose a metal artifact reduction (MAR) algorithm based on dual-domain denoising diffusion probabilistic models (DDPMs). Our approach begins with preprocessing with linear interpolation (LI) and refinement with a convolutional neural network (CNN) to generate an initial reprojection. Then, two DDPM networks are employed: one to synthesize the corrupted sinogram and the other to optimize the resultant images in the image domain. The experimental results show that our algorithm utilizes two specialized DDPMs and achieves superior performance. The sinogram-domain DDPM reconstructs a high-quality sinogram, while the image-domain DDPM effectively removes remaining artifacts. Synergistically, these contributions lead to a significant improvement in overall image quality. Furthermore, our method successfully addresses the hallucination issues observed in the generic DDPM, enhancing the applicability of DDPM in medical imaging.","PeriodicalId":46807,"journal":{"name":"IEEE Transactions on Radiation and Plasma Medical Sciences","volume":"10 2","pages":"229-239"},"PeriodicalIF":3.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11059998","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-26DOI: 10.1109/TRPMS.2025.3583554
Paweł Moskal;Aleksander Bilewicz;Manish Das;Bangyan Huang;Aleksander Khreptak;Szymon Parzych;Jinyi Qi;Axel Rominger;Robert Seifert;Sushil Sharma;Kuangyu Shi;William M. Steinberger;Rafał Walczak;Ewa Stępień
Positronium imaging was recently proposed to image the properties of positronium atoms in the patient’s body. Positronium properties depend on the size of intramolecular voids and oxygen concentration; therefore, they deliver information different from the anatomic, morphological, and metabolic images. Thus far, the mean ortho-positronium (oPs) lifetime imaging has been at the center of research interest. The first ex vivo and in vivo positronium lifetime images of humans have been demonstrated with the dedicated Jagiellonian Positron Emission Tomograph scanner, enabling simultaneous registration of annihilation photons and prompt gamma from $beta ^{+}gamma $ emitters. Annihilation photons are used to reconstruct the annihilation place and time, while prompt gamma is used to reconstruct the time of positronium formation. This review describes recent achievements in the translation of positronium imaging into clinics. The first measurements of positronium lifetime in humans with commercial positron emission tomograph scanners modernized to register triple coincidences are reported. The in vivo observations of differences in oPs lifetime between tumor and healthy tissues and between different oxygen concentrations are discussed. So far, the positronium lifetime measurements in humans have been completed with clinically available 68Ga, 82Rb, and 124I radionuclides. Status and challenges in developing positronium imaging on a way to a clinically useful procedure are presented and discussed.
{"title":"Positronium Imaging: History, Current Status, and Future Perspectives","authors":"Paweł Moskal;Aleksander Bilewicz;Manish Das;Bangyan Huang;Aleksander Khreptak;Szymon Parzych;Jinyi Qi;Axel Rominger;Robert Seifert;Sushil Sharma;Kuangyu Shi;William M. Steinberger;Rafał Walczak;Ewa Stępień","doi":"10.1109/TRPMS.2025.3583554","DOIUrl":"https://doi.org/10.1109/TRPMS.2025.3583554","url":null,"abstract":"Positronium imaging was recently proposed to image the properties of positronium atoms in the patient’s body. Positronium properties depend on the size of intramolecular voids and oxygen concentration; therefore, they deliver information different from the anatomic, morphological, and metabolic images. Thus far, the mean ortho-positronium (oPs) lifetime imaging has been at the center of research interest. The first ex vivo and in vivo positronium lifetime images of humans have been demonstrated with the dedicated Jagiellonian Positron Emission Tomograph scanner, enabling simultaneous registration of annihilation photons and prompt gamma from <inline-formula> <tex-math>$beta ^{+}gamma $ </tex-math></inline-formula> emitters. Annihilation photons are used to reconstruct the annihilation place and time, while prompt gamma is used to reconstruct the time of positronium formation. This review describes recent achievements in the translation of positronium imaging into clinics. The first measurements of positronium lifetime in humans with commercial positron emission tomograph scanners modernized to register triple coincidences are reported. The in vivo observations of differences in oPs lifetime between tumor and healthy tissues and between different oxygen concentrations are discussed. So far, the positronium lifetime measurements in humans have been completed with clinically available 68Ga, 82Rb, and 124I radionuclides. Status and challenges in developing positronium imaging on a way to a clinically useful procedure are presented and discussed.","PeriodicalId":46807,"journal":{"name":"IEEE Transactions on Radiation and Plasma Medical Sciences","volume":"9 8","pages":"981-1001"},"PeriodicalIF":3.5,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11052872","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145435703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-26DOI: 10.1109/TRPMS.2025.3581801
C. Riera-Llobet;P. Ibáñez;C. Fleta;M. C. Jiménez-Ramos;J. García López;D. Bachiller-Perea;C. Guardiola
This work presents the first findings of microdosimetry measurements covering 12 cm$times 0.4$ mm of sensitive area on low-energy proton beams (3–14 MeV) of the cyclotron at the National Center of Accelerators (CNA, Spain) with clinical-equivalent fluence rates $({sim } 10^{7} {mathrm { protons}}cdot {mathrm { cm}}^{-2} cdot {mathrm { s}}^{-1})$ . Sensors are arrays of silicon-based 3D-microdetectors ($20~mu {mathrm { m}}$ thickness, $25~mu rm m$ diameter) that were manufactured at the National Microelectronics Centre (IMB-CNM, CSIC) in Spain. Microdosimetry spectra were recorded at several proton energies both individually and in dual irradiation mode. Tool for particle simulation-based Monte-Carlo simulations recreating the experimental configuration were also performed to compare with the experimental data. A good agreement was found between the simulated and the experimental spectra. The experimental $bar {y}_{f}$ values in silicon covered from ($6pm 1$ ) to ($17.4pm 0.5$ ) ${mathrm { keV}}mu rm m^{-1}$ . To the best of our knowledge, this is the largest radiation sensitive surface covered with microdosimeters so far.
{"title":"First Experimental Microdosimetry Maps in Low-Energy Cyclotron Proton Beams","authors":"C. Riera-Llobet;P. Ibáñez;C. Fleta;M. C. Jiménez-Ramos;J. García López;D. Bachiller-Perea;C. Guardiola","doi":"10.1109/TRPMS.2025.3581801","DOIUrl":"https://doi.org/10.1109/TRPMS.2025.3581801","url":null,"abstract":"This work presents the first findings of microdosimetry measurements covering 12 cm<inline-formula> <tex-math>$times 0.4$ </tex-math></inline-formula> mm of sensitive area on low-energy proton beams (3–14 MeV) of the cyclotron at the National Center of Accelerators (CNA, Spain) with clinical-equivalent fluence rates <inline-formula> <tex-math>$({sim } 10^{7} {mathrm { protons}}cdot {mathrm { cm}}^{-2} cdot {mathrm { s}}^{-1})$ </tex-math></inline-formula>. Sensors are arrays of silicon-based 3D-microdetectors (<inline-formula> <tex-math>$20~mu {mathrm { m}}$ </tex-math></inline-formula> thickness, <inline-formula> <tex-math>$25~mu rm m$ </tex-math></inline-formula> diameter) that were manufactured at the National Microelectronics Centre (IMB-CNM, CSIC) in Spain. Microdosimetry spectra were recorded at several proton energies both individually and in dual irradiation mode. Tool for particle simulation-based Monte-Carlo simulations recreating the experimental configuration were also performed to compare with the experimental data. A good agreement was found between the simulated and the experimental spectra. The experimental <inline-formula> <tex-math>$bar {y}_{f}$ </tex-math></inline-formula> values in silicon covered from (<inline-formula> <tex-math>$6pm 1$ </tex-math></inline-formula>) to (<inline-formula> <tex-math>$17.4pm 0.5$ </tex-math></inline-formula>) <inline-formula> <tex-math>${mathrm { keV}}mu rm m^{-1}$ </tex-math></inline-formula>. To the best of our knowledge, this is the largest radiation sensitive surface covered with microdosimeters so far.","PeriodicalId":46807,"journal":{"name":"IEEE Transactions on Radiation and Plasma Medical Sciences","volume":"10 2","pages":"288-298"},"PeriodicalIF":3.5,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-20DOI: 10.1109/TRPMS.2025.3579351
Jiawen Zhou;Fei Wang;Chao Cai;Qingguo Xie
The coincident event analysis is of paramount importance in positron emission tomography (PET). The result of this process, often termed coincidence time resolution (CTR), is one of the most important quantitative factors that determines the performance of a PET system. Optimizing CTR, typically attempted by lowering threshold voltages in leading edge discriminators (LEDs), presents a challenge due to prevalent pick-up noises. In light of this, in this article, a post-processing algorithm is proposed. This algorithm is dedicated to a detector front-end with the addition of a low noise amplifier (LNA). It can effectively identify outliers and tackle signal distortions so as to mitigate pick-up noises and finally improve CTR. The key contribution of this study is that it can notably improve CTR while still maintaining adequate detection efficiency. Extensive experiments are carried out to demonstrate that the proposed post-processing algorithm can effectively improve CTR, from about 240 ps down to around 100 ps, even with a crystal length of 20 mm (the energy window is 450 to 600 keV). The power consumption of the single channel is only 0.12 W.
{"title":"A Post-Processing Algorithm to Correct Time Walk and Boost CTR to 100 ps Level","authors":"Jiawen Zhou;Fei Wang;Chao Cai;Qingguo Xie","doi":"10.1109/TRPMS.2025.3579351","DOIUrl":"https://doi.org/10.1109/TRPMS.2025.3579351","url":null,"abstract":"The coincident event analysis is of paramount importance in positron emission tomography (PET). The result of this process, often termed coincidence time resolution (CTR), is one of the most important quantitative factors that determines the performance of a PET system. Optimizing CTR, typically attempted by lowering threshold voltages in leading edge discriminators (LEDs), presents a challenge due to prevalent pick-up noises. In light of this, in this article, a post-processing algorithm is proposed. This algorithm is dedicated to a detector front-end with the addition of a low noise amplifier (LNA). It can effectively identify outliers and tackle signal distortions so as to mitigate pick-up noises and finally improve CTR. The key contribution of this study is that it can notably improve CTR while still maintaining adequate detection efficiency. Extensive experiments are carried out to demonstrate that the proposed post-processing algorithm can effectively improve CTR, from about 240 ps down to around 100 ps, even with a crystal length of 20 mm (the energy window is 450 to 600 keV). The power consumption of the single channel is only 0.12 W.","PeriodicalId":46807,"journal":{"name":"IEEE Transactions on Radiation and Plasma Medical Sciences","volume":"9 8","pages":"1002-1014"},"PeriodicalIF":3.5,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145435711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-19DOI: 10.1109/TRPMS.2025.3581204
Se-In Jang;Cristina Lois Gomez;Alex Becker;Emma Thibault;Julie C. Price;Keith A. Johnson;Georges El Fakhri;Kuang Gong
Tau PET imaging is an essential imaging modality for the diagnosis and monitoring of Alzheimer’s disease and related dementias. To enable tau PET imaging-based longitudinal monitoring of disease progression, further reducing the injected dose during each scan is important. In this work, we developed a novel deep learning approach that incorporated cross-modality transformer blocks to integrate both PET and MR prior information to further improve low-dose tau PET imaging. Both spatial and channel information were utilized during the calculation of cross-modality self-attention maps. Performance of the proposed method was evaluated based on the early-frame and late-frame images from 139 dynamic 18F-MK-6240 tau PET datasets. Results showed that the proposed network can outperform other reference networks which concatenated PET and MR images together as the network input.
Tau PET成像是诊断和监测阿尔茨海默病及相关痴呆的重要成像方式。为了实现基于tau PET成像的疾病进展纵向监测，在每次扫描期间进一步减少注射剂量是重要的。在这项工作中，我们开发了一种新的深度学习方法，该方法结合了跨模态变压器块来整合PET和MR先验信息，以进一步改善低剂量tau PET成像。在计算跨模态自注意图时同时利用了空间信息和通道信息。基于139个动态18F-MK-6240 tau PET数据集的早帧和晚帧图像，对所提方法的性能进行了评估。结果表明，该网络的性能优于将PET和MR图像拼接在一起作为网络输入的参考网络。
{"title":"A Cross-Modality Transformer Network for MR-Guided Low-Dose Tau PET Image Denoising","authors":"Se-In Jang;Cristina Lois Gomez;Alex Becker;Emma Thibault;Julie C. Price;Keith A. Johnson;Georges El Fakhri;Kuang Gong","doi":"10.1109/TRPMS.2025.3581204","DOIUrl":"https://doi.org/10.1109/TRPMS.2025.3581204","url":null,"abstract":"Tau PET imaging is an essential imaging modality for the diagnosis and monitoring of Alzheimer’s disease and related dementias. To enable tau PET imaging-based longitudinal monitoring of disease progression, further reducing the injected dose during each scan is important. In this work, we developed a novel deep learning approach that incorporated cross-modality transformer blocks to integrate both PET and MR prior information to further improve low-dose tau PET imaging. Both spatial and channel information were utilized during the calculation of cross-modality self-attention maps. Performance of the proposed method was evaluated based on the early-frame and late-frame images from 139 dynamic 18F-MK-6240 tau PET datasets. Results showed that the proposed network can outperform other reference networks which concatenated PET and MR images together as the network input.","PeriodicalId":46807,"journal":{"name":"IEEE Transactions on Radiation and Plasma Medical Sciences","volume":"10 2","pages":"249-257"},"PeriodicalIF":3.5,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-17DOI: 10.1109/TRPMS.2025.3580379
Leonor Rebolo;Ryan Heller;Marta Freire;Pedro Correia;Ana Luisa Silva;Sara St. James;Antonio J. González;Joshua W. Cates;Gerard Ariño-Estrada
proton range verification (PRV) in proton therapy is an unmet clinical need. prompt-gamma imaging (PGI) using thick collimators is a PRV modality that has obtained the most success to-date. The gamma detectors in such approach consist of scintillation crystals coupled to photodetectors. In this work, we report the development and use of detectors made of monolithic pure Cherenkov emitter crystals for the same purpose. We demonstrate for the first time the ability of such detector configuration to provide spatial resolution information in one direction using measurements from a collimated slit. The detector consisted of a PbF2 crystal with dimensions $25times 25times $ 10 mm3 coupled to a S13361-3050AE-08 array of $8times 8$ SiPMs from Hamamatsu. The SiPM array was connected to a row-column readout, with 8+8 channels, and triggered on the sum of the columns. Three different event reconstruction algorithms were tested: center of gravity (CoG), rise to the power (RTP), and neural network (NN). The NN yielded the best spatial resolution, with $3.7pm 0$ .9 mm full width half maximum (FWHM) in average for all positions. CoG and RTP also showed a consistent shift with the change of position of the slit, although with more modest results, between 4 and 7 mm in average for all positions. This is the first characterization of monolithic pure Cherenkov emitters for Multi-MeV gamma imaging. Results are promising for this detector concept, showing that it can offer an alternative for collimated PGI in PRV with potential of sustaining high count rates, with effective background rejection, and low production costs based on the cost of primary components of the crystals.
{"title":"CHEMONO: A Cherenkov-Only Monolithic Detector for PGI in Proton Range Verification","authors":"Leonor Rebolo;Ryan Heller;Marta Freire;Pedro Correia;Ana Luisa Silva;Sara St. James;Antonio J. González;Joshua W. Cates;Gerard Ariño-Estrada","doi":"10.1109/TRPMS.2025.3580379","DOIUrl":"https://doi.org/10.1109/TRPMS.2025.3580379","url":null,"abstract":"proton range verification (PRV) in proton therapy is an unmet clinical need. prompt-gamma imaging (PGI) using thick collimators is a PRV modality that has obtained the most success to-date. The gamma detectors in such approach consist of scintillation crystals coupled to photodetectors. In this work, we report the development and use of detectors made of monolithic pure Cherenkov emitter crystals for the same purpose. We demonstrate for the first time the ability of such detector configuration to provide spatial resolution information in one direction using measurements from a collimated slit. The detector consisted of a PbF2 crystal with dimensions <inline-formula> <tex-math>$25times 25times $ </tex-math></inline-formula> 10 mm3 coupled to a S13361-3050AE-08 array of <inline-formula> <tex-math>$8times 8$ </tex-math></inline-formula> SiPMs from Hamamatsu. The SiPM array was connected to a row-column readout, with 8+8 channels, and triggered on the sum of the columns. Three different event reconstruction algorithms were tested: center of gravity (CoG), rise to the power (RTP), and neural network (NN). The NN yielded the best spatial resolution, with <inline-formula> <tex-math>$3.7pm 0$ </tex-math></inline-formula>.9 mm full width half maximum (FWHM) in average for all positions. CoG and RTP also showed a consistent shift with the change of position of the slit, although with more modest results, between 4 and 7 mm in average for all positions. This is the first characterization of monolithic pure Cherenkov emitters for Multi-MeV gamma imaging. Results are promising for this detector concept, showing that it can offer an alternative for collimated PGI in PRV with potential of sustaining high count rates, with effective background rejection, and low production costs based on the cost of primary components of the crystals.","PeriodicalId":46807,"journal":{"name":"IEEE Transactions on Radiation and Plasma Medical Sciences","volume":"10 2","pages":"268-275"},"PeriodicalIF":3.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-16DOI: 10.1109/TRPMS.2025.3579209
Maxime Toussaint;Francis Loignon-Houle;Jean-Pierre Dussault;Roger Lecomte
One of the limiting factors of spatial resolution in positron emission tomography (PET) imaging is annihilation photon acollinearity (APA). For whole-body PET scanners, APA induces a blur ranging from 1.7 to 2.2 mm FWHM. For long axial field-of-view (FOV) scanners, this range increases even more, depending on the maximum ring difference. It was previously shown that perfect time-of-flight (TOF) resolution sharpens the APA-induced blur by altering its expected Gaussian shape into a profile resembling a 1/r function, thereby reducing its contribution to spatial resolution loss. This suggests that the conventional theoretical limit of PET spatial resolution could be overcome if sufficient TOF resolution can be achieved. However, the requirements to achieve an observable gain in spatial resolution have yet to be explored. We propose an investigation of these requirements for whole-body and long axial FOV scanners, in terms of TOF resolution and count statistics. Using a fictive 81-cm diameter scanner with 2-mm wide detectors, we show that ultrafast TOF resolution—13 ps FWHM—enables an observable gain in spatial resolution for a range of count statistics. In addition, we show that lower TOF resolutions (i.e., higher TOF values of 27 or 67 ps) could mitigate APA for the oblique tubes of response of long axial FOV systems subjected to larger APA blurring. This last observation is of particular interest as it suggests that the nonstationary nature of spatial resolution in PET imaging can be further mitigated when such TOF precision is achieved.
{"title":"Time-of-Flight Requirements to Mitigate Blurring Induced by Annihilation Photon Acollinearity","authors":"Maxime Toussaint;Francis Loignon-Houle;Jean-Pierre Dussault;Roger Lecomte","doi":"10.1109/TRPMS.2025.3579209","DOIUrl":"https://doi.org/10.1109/TRPMS.2025.3579209","url":null,"abstract":"One of the limiting factors of spatial resolution in positron emission tomography (PET) imaging is annihilation photon acollinearity (APA). For whole-body PET scanners, APA induces a blur ranging from 1.7 to 2.2 mm FWHM. For long axial field-of-view (FOV) scanners, this range increases even more, depending on the maximum ring difference. It was previously shown that perfect time-of-flight (TOF) resolution sharpens the APA-induced blur by altering its expected Gaussian shape into a profile resembling a 1/r function, thereby reducing its contribution to spatial resolution loss. This suggests that the conventional theoretical limit of PET spatial resolution could be overcome if sufficient TOF resolution can be achieved. However, the requirements to achieve an observable gain in spatial resolution have yet to be explored. We propose an investigation of these requirements for whole-body and long axial FOV scanners, in terms of TOF resolution and count statistics. Using a fictive 81-cm diameter scanner with 2-mm wide detectors, we show that ultrafast TOF resolution—13 ps FWHM—enables an observable gain in spatial resolution for a range of count statistics. In addition, we show that lower TOF resolutions (i.e., higher TOF values of 27 or 67 ps) could mitigate APA for the oblique tubes of response of long axial FOV systems subjected to larger APA blurring. This last observation is of particular interest as it suggests that the nonstationary nature of spatial resolution in PET imaging can be further mitigated when such TOF precision is achieved.","PeriodicalId":46807,"journal":{"name":"IEEE Transactions on Radiation and Plasma Medical Sciences","volume":"10 2","pages":"210-217"},"PeriodicalIF":3.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
time-of-flight positron emission tomography (TOF-PET) and proton range verification (PRV) in proton therapy are based on the detection of gamma photons. Despite the difference in the ultimate goal and status of each of these two modalities, both heavily rely on the gamma detectors used in associated imaging systems. The emission of Cherenkov light has been studied extensively over the last decade as a gamma-detection signature in different detector configurations for TOF-PET and PRV. This review aims at: 1) capturing the breadth of works that report on using Cherenkov light for these applications from a detector instrumentation perspective and 2) summarizing barriers encountered by these approaches in their path toward commercial adoption. This review is structured in seven sections: I) brief introduction of TOF-PET and PRV needs that might be addressed with Cherenkov-based gamma detectors; II) physics of Cherenkov emission, propagation, and detection; experimental efforts in detector characterization grouped by the nature of the signals involved in the detector, i.e., III) simultaneous emission of Cherenkov and scintillation light; IV) pure Cherenkov emitters; and V) semiconductor detectors with simultaneous Cherenkov emission; Section VI consolidates the information with a special attention to challenges and potential strategies to overcome them; and Section VII concludes with a short paragraph. We hope this comprehensive review of the extensive work of researchers in this field in the last decade triggers further discussion and sparks inspiration among the community.
{"title":"Current Status of Cherenkov-Based Gamma Detectors for TOF-PET and Proton Range Verification","authors":"Gerard Ariño-Estrada;Nicolaus Kratochwil;Stefan Gundacker;Emilie Roncali","doi":"10.1109/TRPMS.2025.3579673","DOIUrl":"https://doi.org/10.1109/TRPMS.2025.3579673","url":null,"abstract":"time-of-flight positron emission tomography (TOF-PET) and proton range verification (PRV) in proton therapy are based on the detection of gamma photons. Despite the difference in the ultimate goal and status of each of these two modalities, both heavily rely on the gamma detectors used in associated imaging systems. The emission of Cherenkov light has been studied extensively over the last decade as a gamma-detection signature in different detector configurations for TOF-PET and PRV. This review aims at: 1) capturing the breadth of works that report on using Cherenkov light for these applications from a detector instrumentation perspective and 2) summarizing barriers encountered by these approaches in their path toward commercial adoption. This review is structured in seven sections: I) brief introduction of TOF-PET and PRV needs that might be addressed with Cherenkov-based gamma detectors; II) physics of Cherenkov emission, propagation, and detection; experimental efforts in detector characterization grouped by the nature of the signals involved in the detector, i.e., III) simultaneous emission of Cherenkov and scintillation light; IV) pure Cherenkov emitters; and V) semiconductor detectors with simultaneous Cherenkov emission; <xref>Section VI</xref> consolidates the information with a special attention to challenges and potential strategies to overcome them; and <xref>Section VII</xref> concludes with a short paragraph. We hope this comprehensive review of the extensive work of researchers in this field in the last decade triggers further discussion and sparks inspiration among the community.","PeriodicalId":46807,"journal":{"name":"IEEE Transactions on Radiation and Plasma Medical Sciences","volume":"10 1","pages":"1-15"},"PeriodicalIF":3.5,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11036331","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145859875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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