EJNMMI Physics最新文献

{"title":"Feasibility of shortening scan duration of ¹⁸F-FDG myocardial metabolism imaging using a total-body PET/CT scanner.","authors":"Xiaochun Zhang, Zeyin Xiang, Fanghu Wang, Chunlei Han, Qing Zhang, Entao Liu, Hui Yuan, Lei Jiang","doi":"10.1186/s40658-024-00689-1","DOIUrl":"10.1186/s40658-024-00689-1","url":null,"abstract":"<p><strong>Purpose: </strong>To evaluate ¹⁸F-FDG myocardial metabolism imaging (MMI) using a total-body PET/CT scanner and explore the feasible scan duration to guide the clinical practice.</p><p><strong>Methods: </strong>A retrospective analysis was conducted on 41 patients who underwent myocardial perfusion-metabolism imaging to assess myocardial viability. The patients underwent ¹⁸F-FDG MMI with a total-body PET/CT scanner using a list-mode for 600 s. PET data were trimmed and reconstructed to simulate images of 600-s, 300-s, 120-s, 60-s, and 30-s acquisition time (G600-G30). Images among different groups were subjectively evaluated using a 5-point Likert scale. Semi-quantitative evaluation was performed using standardized uptake value (SUV), myocardial to background activity ratio (M/B), signal to noise ratio (SNR), contrast to noise ratio (CNR), contrast ratio (CR), and coefficient of variation (CV). Myocardial viability analysis included indexes of Mismatch and Scar. G600 served as the reference.</p><p><strong>Results: </strong>Subjective visual evaluation indicated a decline in the scores of image quality with shortening scan duration. All the G600, G300, and G120 images were clinically acceptable (score ≥ 3), and their image quality scores were 4.9 ± 0.3, 4.8 ± 0.4, and 4.5 ± 0.8, respectively (P > 0.05). Moreover, as the scan duration reduced, the semi-quantitative parameters M/B, SNR, CNR, and CR decreased, while SUV and CV increased, and significant difference was observed in G300-G30 groups when comparing to G600 group (P < 0.05). For myocardial viability analysis of left ventricular and coronary segments, the Mismatch and Scar values of G300-G30 groups were almost identical to G600 group (ICC: 0.968-1.0, P < 0.001).</p><p><strong>Conclusion: </strong>Sufficient image quality for clinical diagnosis could be achieved at G120 for MMI using a total-body PET/CT scanner, while the image quality of G30 was acceptable for myocardial viability analysis.</p>","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":"11 1","pages":"83"},"PeriodicalIF":3.0,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11467154/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142399764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SPECT-MPI iterative denoising during the reconstruction process using a two-phase learned convolutional neural network.","authors":"Farnaz Yousefzadeh, Mehran Yazdi, Seyed Mohammad Entezarmahdi, Reza Faghihi, Sadegh Ghasempoor, Negar Shahamiri, Zahra Abuee Mehrizi, Mahdi Haghighatafshar","doi":"10.1186/s40658-024-00687-3","DOIUrl":"10.1186/s40658-024-00687-3","url":null,"abstract":"<p><strong>Purpose: </strong>The problem of image denoising in single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is a fundamental challenge. Although various image processing techniques have been presented, they may degrade the contrast of denoised images. The proposed idea in this study is to use a deep neural network as the denoising procedure during the iterative reconstruction process rather than the post-reconstruction phase. This method could decrease the background coefficient of variation (COV_bkg) of the final reconstructed image, which represents the amount of random noise, while improving the contrast-to-noise ratio (CNR).</p><p><strong>Methods: </strong>In this study, a generative adversarial network is used, where its generator is trained by a two-phase approach. In the first phase, the network is trained by a confined image region around the heart in transverse view. The second phase improves the network's generalization by tuning the network weights with the full image size as the input. The network was trained and tested by a dataset of 247 patients who underwent two immediate serially high- and low-noise SPECT-MPI.</p><p><strong>Results: </strong>Quantitative results show that compared to post-reconstruction low pass filtering and post-reconstruction deep denoising methods, our proposed method can decline the COV_bkg of the images by up to 10.28% and 12.52% and enhance the CNR by up to 54.54% and 45.82%, respectively.</p><p><strong>Conclusion: </strong>The iterative deep denoising method outperforms 2D low-pass Gaussian filtering with an 8.4-mm FWHM and post-reconstruction deep denoising approaches.</p>","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":"11 1","pages":"82"},"PeriodicalIF":3.0,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11461437/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142388947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PET radiomics in lung cancer: advances and translational challenges.","authors":"Yongbai Zhang, Wenpeng Huang, Hao Jiao, Lei Kang","doi":"10.1186/s40658-024-00685-5","DOIUrl":"10.1186/s40658-024-00685-5","url":null,"abstract":"<p><p>Radiomics is an emerging field of medical imaging that aims at improving the accuracy of diagnosis, prognosis, treatment planning and monitoring non-invasively through the automated or semi-automated quantitative analysis of high-dimensional image features. Specifically in the field of nuclear medicine, radiomics utilizes imaging methods such as positron emission tomography (PET) and single photon emission computed tomography (SPECT) to evaluate biomarkers related to metabolism, blood flow, cellular activity and some biological pathways. Lung cancer ranks among the leading causes of cancer-related deaths globally, and radiomics analysis has shown great potential in guiding individualized therapy, assessing treatment response, and predicting clinical outcomes. In this review, we summarize the current state-of-the-art radiomics progress in lung cancer, highlighting the potential benefits and existing limitations of this approach. The radiomics workflow was introduced first including image acquisition, segmentation, feature extraction, and model building. Then the published literatures were described about radiomics-based prediction models for lung cancer diagnosis, differentiation, prognosis and efficacy evaluation. Finally, we discuss current challenges and provide insights into future directions and potential opportunities for integrating radiomics into routine clinical practice.</p>","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":"11 1","pages":"81"},"PeriodicalIF":3.0,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11450131/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142364846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep learning-based multi-frequency denoising for myocardial perfusion SPECT.","authors":"Yu Du, Jingzhang Sun, Chien-Ying Li, Bang-Hung Yang, Tung-Hsin Wu, Greta S P Mok","doi":"10.1186/s40658-024-00680-w","DOIUrl":"10.1186/s40658-024-00680-w","url":null,"abstract":"<p><strong>Background: </strong>Deep learning (DL)-based denoising has been proven to improve image quality and quantitation accuracy of low dose (LD) SPECT. However, conventional DL-based methods used SPECT images with mixed frequency components. This work aims to develop an integrated multi-frequency denoising network to further enhance LD myocardial perfusion (MP) SPECT denoising.</p><p><strong>Methods: </strong>Fifty anonymized patients who underwent routine ^99mTc-sestamibi stress SPECT/CT scans were retrospectively recruited. Three LD datasets were obtained by reducing the 10 s acquisition time of full dose (FD) SPECT to be 5, 2 and 1 s per projection based on the list mode data for a total of 60 projections. FD and LD projections were Fourier transformed to magnitude and phase images, which were then separated into two or three frequency bands. Each frequency band was then inversed Fourier transformed back to the image domain. We proposed a 3D integrated attention-guided multi-frequency conditional generative adversarial network (AttMFGAN) and compared with AttGAN, and separate AttGAN for multi-frequency bands denoising (AttGAN-MF).The multi-frequency FD and LD projections of 35, 5 and 10 patients were paired for training, validation and testing. The LD projections to be tested were separated to multi-frequency components and input to corresponding networks to get the denoised components, which were summed to get the final denoised projections. Voxel-based error indices were measured on the cardiac region on the reconstructed images. The perfusion defect size (PDS) was also analyzed.</p><p><strong>Results: </strong>AttGAN-MF and AttMFGAN have superior performance on all physical and clinical indices as compared to conventional AttGAN. The integrated AttMFGAN is better than AttGAN-MF. Multi-frequency denoising with two frequency bands have generally better results than corresponding three-frequency bands methods.</p><p><strong>Conclusions: </strong>AttGAN-MF and AttMFGAN are promising to further improve LD MP SPECT denoising.</p>","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":"11 1","pages":"80"},"PeriodicalIF":3.0,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11447183/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142361340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reproducibility of [¹⁸F]MK-6240 kinetics in brain studies with shortened dynamic PET protocol in healthy/cognitively normal subjects.","authors":"Phelipi N Schuck, Xiuyuan H Wang, Emily B Tanzi, Sally Xie, Yi Li, Sadek A Nehmeh","doi":"10.1186/s40658-024-00679-3","DOIUrl":"https://doi.org/10.1186/s40658-024-00679-3","url":null,"abstract":"<p><strong>Background: </strong>[¹⁸F]MK-6240 is a neurofibrillary tangles PET radiotracer that has been broadly used in aging and Alzheimer's disease (AD) studies. Majority of [¹⁸F]MK-6240 PET studies use dynamic acquisitions longer than 60 min to assess the tracer kinetic parameters. As of today, no consensus has been established on the optimum dynamic PET scan time. In this study, we assess the reproducibility of [¹⁸F]MK-6240 quantitative metrics using shortest dynamic PET protocols in cognitively normal subjects. PET metrics were measured through two-tissue compartment model (2TCM) and Logan model to estimate VT and DVR, as well as SUVR from 90 to 120 min (SUVR_{90 - 120 min}) post-tracer injection for brain regions. 2TCM was carried out using the 120 min dynamic coffee break dataset (first scan from 0 to 60 min p.i., second scan from 90 to 120 min p.i.) and then repeated after stepwise shortening it by 5 min. The dynamic scan length that reproduced the 120 min dynamic scans-based VT to within 10% error was defined as the shortest acquisition time (SAT). The SAT SUVR_{90 - 120 min} was deduced from the SAT dataset by extrapolation of each image pixel time-activity curve to 120 min. The reproducibility of the 120 min dynamic scans-based VT_2TCM, DVR_2TCM, DVR_Logan, and SUVR using the SAT was assessed using Passing-Bablock analysis. The limits of reproducibility of each PET metrics were determined using Bland-Altman analysis.</p><p><strong>Results: </strong>A dynamic SAT of 40 min yielded < 10% error in [¹⁸F]MK-6240 VT_2TCM's for all brain regions, compared to those measured using the 120 min datasets. SAT-based analysis did not show statistically significant systemic or proportional biases in VT_2TCM, DVR_2TCM, DVR_Logan, or SUVR compared to those deduced from the full dynamic dataset of 120 min. A mean difference between the 120 min- and SAT-based analysis of less than 4%, 10%, 15%, and 20% existed in the VT_2TCM, DVR_2TCM, DVR_Logan, and SUVR respectively.</p><p><strong>Conclusion: </strong>Kinetic modeling of [¹⁸F]MK-6240 PET can be accurately performed using dynamic scan times as short as 40 min. This can facilitate studies with [¹⁸F]MK-6240 PET and improve patients accrual. Further work would be necessary to confirm the reproducibility of these results for patients in dementia spectra.</p>","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":"11 1","pages":"79"},"PeriodicalIF":3.0,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11436579/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142343806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Accuracy of holmium-166 SPECT/CT quantification over a large range of activities.","authors":"Lovisa E L Westlund Gotby, Daphne Lobeek, Joey Roosen, Maarten de Bakker, Mark W Konijnenberg, J Frank W Nijsen","doi":"10.1186/s40658-024-00683-7","DOIUrl":"https://doi.org/10.1186/s40658-024-00683-7","url":null,"abstract":"<p><strong>Background: </strong>Quantitative imaging is a crucial step for dosimetry in radionuclide therapies. Traditionally, SPECT/CT imaging is quantified based on scanner-specific conversion factors or self-calibration, but recently absolute quantification methods have been introduced in commercial SPECT reconstruction software (Broad Quantification, Siemens Healthineers). In this phantom study we investigate the accuracy of three quantification methods for holmium-166 SPECT/CT imaging, and provide recommendations for clinical dosimetry.</p><p><strong>Methods: </strong>One cylindrical phantom, filled with a homogeneous holmium-166-chloride activity concentration solution, was imaged at one time point to determine a scanner-specific conversion factor, and to characterize the spatial dependency of the activity concentration recovery. One Jaszczak phantom with six fillable spheres, 10:1 sphere-to-background ratio, was imaged over a large range of holmium-166 activities (61-3130 MBq). The images were reconstructed with either an ordered subset expectation maximization (OSEM, Flash3D-reconstruction; scanner-specific quantification or self-calibration quantification) or an ordered subset conjugate gradient (OSCG, xSPECT-reconstruction; Broad Quantification) algorithm. These three quantification methods were compared for the data of the Jaszczak phantom and evaluated based on whole phantom recovered activity, activity concentration recovery coefficients (ACRC), and recovery curves.</p><p><strong>Results: </strong>The activity recovery in the Jaszczak phantom was 28-115% for the scanner-specific, and 57-97% for the Broad Quantification quantification methods, respectively. The self-calibration-based activity recovery is inherently always 100%. The ACRC for the largest sphere (Ø60 mm, ~ 113 mL) ranged over (depending on the activity level) 0.22-0.89, 0.76-0.86, 0.39-0.72 for scanner-specific, self-calibration and Broad Quantification, respectively.</p><p><strong>Conclusion: </strong>Of the three investigated quantification methods, the self-calibration technique produces quantitative SPECT images with the highest accuracy in the investigated holmium-166 activity range.</p>","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":"11 1","pages":"78"},"PeriodicalIF":3.0,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11427639/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142343805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative SPECT imaging of 155Tb and 161Tb for preclinical theranostic radiopharmaceutical development","authors":"Helena Koniar, Scott McNeil, Luke Wharton, Aidan Ingham, Michiel Van de Voorde, Maarten Ooms, Sathiya Sekar, Cristina Rodríguez-Rodríguez, Peter Kunz, Valery Radchenko, Arman Rahmim, Carlos Uribe, Hua Yang, Paul Schaffer","doi":"10.1186/s40658-024-00682-8","DOIUrl":"https://doi.org/10.1186/s40658-024-00682-8","url":null,"abstract":"Element-equivalent matched theranostic pairs facilitate quantitative in vivo imaging to establish pharmacokinetics and dosimetry estimates in the development of preclinical radiopharmaceuticals. Terbium radionuclides have significant potential as matched theranostic pairs for multipurpose applications in nuclear medicine. In particular, 155Tb (t1/2 = 5.32 d) and 161Tb (t1/2 = 6.89 d) have been proposed as a theranostic pair for their respective applications in single photon emission computed tomography (SPECT) imaging and targeted beta therapy. Our study assessed the performance of preclinical quantitative SPECT imaging with 155Tb and 161Tb. A hot rod resolution phantom with rod diameters ranging between 0.85 and 1.70 mm was filled with either 155Tb (21.8 ± 1.7 MBq/mL) or 161Tb (23.6 ± 1.9 MBq/mL) and scanned with the VECTor preclinical SPECT/CT scanner. Image performance was evaluated with two collimators: a high energy ultra high resolution (HEUHR) collimator and an extra ultra high sensitivity (UHS) collimator. SPECT images were reconstructed from photopeaks at 43.0 keV, 86.6 keV, and 105.3 keV for 155Tb and 48.9 keV and 74.6 keV for 161Tb. Quantitative SPECT images of the resolution phantoms were analyzed to report inter-rod contrast, recovery coefficients, and contrast-to-noise metrics. Quantitative SPECT images of the resolution phantom established that the HEUHR collimator resolved all rods for 155Tb and 161Tb, and the UHS collimator resolved rods ≥ 1.10 mm for 161Tb and ≥ 1.30 mm for 155Tb. The HEUHR collimator maintained better quantitative accuracy than the UHS collimator with recovery coefficients up to 92%. Contrast-to-noise metrics were also superior with the HEUHR collimator. Both 155Tb and 161Tb demonstrated potential for applications in preclinical quantitative SPECT imaging. The high-resolution collimator achieves < 0.85 mm resolution and maintains quantitative accuracy in small volumes which is advantageous for assessing sub organ activity distributions in small animals. This imaging method can provide critical quantitative information for assessing and optimizing preclinical Tb-radiopharmaceuticals.","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":"27 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Positronium lifetime validation measurements using a long-axial field-of-view positron emission tomography scanner.","authors":"William M Steinberger, Lorenzo Mercolli, Johannes Breuer, Hasan Sari, Szymon Parzych, Szymon Niedzwiecki, Gabriela Lapkiewicz, Pawel Moskal, Ewa Stepien, Axel Rominger, Kuangyu Shi, Maurizio Conti","doi":"10.1186/s40658-024-00678-4","DOIUrl":"https://doi.org/10.1186/s40658-024-00678-4","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Positron emission tomography (PET) traditionally uses coincident annihilation photons emitted from a positron interacting with an electron to localize cancer within the body. The formation of positronium (Ps), a bonded electron-positron pair, has not been utilized in clinical applications of PET due to the need to detect either the emission of a prompt gamma ray or the decay of higher-order coincident events. Assessment of the lifetime of the formed Ps, however, can potentially yield additional diagnostic information of the surrounding tissue because Ps properties vary due to void size and molecular composition. To assess the feasibility of measuring Ps lifetimes with a PET scanner, experiments were performed in a Biograph Vision Quadra (Siemens Healthineers). Quadra is a long-axial field-of-view (LA-FOV) PET scanner capable of producing list-mode data from single interaction events.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Ortho-Ps (o-Ps) lifetimes were measured for quartz-glass and polycarbonate samples using a &lt;math&gt; &lt;mrow&gt;&lt;mmultiscripts&gt;&lt;mrow&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;/mrow&gt; &lt;mn&gt;22&lt;/mn&gt;&lt;/mmultiscripts&gt; &lt;mtext&gt;Na&lt;/mtext&gt;&lt;/mrow&gt; &lt;/math&gt; positron source. Results produced o-Ps lifetimes of 1.538 ± 0.036 ns for the quartz glass and 1.927 ± 0.042 ns for the polycarbonate. Both o-Ps lifetimes were determined using a double-exponential fit to the time-difference distribution between the emission of a prompt gamma ray and the annihilation of the correlated positron. The measured values match within a single standard deviation of previously published results. The quartz-glass samples were additional measured with &lt;math&gt; &lt;mrow&gt;&lt;mmultiscripts&gt;&lt;mrow&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;/mrow&gt; &lt;mn&gt;82&lt;/mn&gt;&lt;/mmultiscripts&gt; &lt;mtext&gt;Rb&lt;/mtext&gt;&lt;/mrow&gt; &lt;/math&gt; , &lt;math&gt;&lt;mmultiscripts&gt;&lt;mrow&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;/mrow&gt; &lt;mn&gt;68&lt;/mn&gt;&lt;/mmultiscripts&gt; &lt;/math&gt; Ga and &lt;math&gt; &lt;mrow&gt;&lt;mmultiscripts&gt;&lt;mrow&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;/mrow&gt; &lt;mn&gt;124&lt;/mn&gt;&lt;/mmultiscripts&gt; &lt;mtext&gt;I&lt;/mtext&gt;&lt;/mrow&gt; &lt;/math&gt; to validate the lifetime using clinically available sources. A double-exponential fit was initially chosen as a similar methodology to previously published works, however, an exponentially-modified Gaussian distribution fit to each lifetime more-accurately models the data. A Bayesian method was used to estimate the variables of the fit and o-Ps lifetime results are reported using this methodology for the three clinical isotopes: 1.59 ± 0.03 ns for &lt;math&gt; &lt;mrow&gt;&lt;mmultiscripts&gt;&lt;mrow&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;/mrow&gt; &lt;mn&gt;82&lt;/mn&gt;&lt;/mmultiscripts&gt; &lt;mtext&gt;Rb&lt;/mtext&gt;&lt;/mrow&gt; &lt;/math&gt; , 1.58 ± 0.07 ns for &lt;math&gt; &lt;mrow&gt;&lt;mmultiscripts&gt;&lt;mrow&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;/mrow&gt; &lt;mn&gt;68&lt;/mn&gt;&lt;/mmultiscripts&gt; &lt;mtext&gt;Ga&lt;/mtext&gt;&lt;/mrow&gt; &lt;/math&gt; and 1.62 ± 0.01 ns for &lt;math&gt; &lt;mrow&gt;&lt;mmultiscripts&gt;&lt;mrow&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;/mrow&gt; &lt;mn&gt;124&lt;/mn&gt;&lt;/mmultiscripts&gt; &lt;mtext&gt;I&lt;/mtext&gt;&lt;/mrow&gt; &lt;/math&gt; . The impact of scatter and attenuation on the o-Ps lifetime was also assessed by analyzing a water-filled uniform cylinder (20 &lt;math&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/math&gt; &lt;math&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;/math&gt; 30","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":"11 1","pages":"76"},"PeriodicalIF":3.0,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11362402/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142105489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feasibility of a deep-inspiration breath-hold [¹⁸F]AlF-NOTA-LM3 PET/CT imaging on upper-abdominal lesions in NET patients: in comparison with respiratory-gated PET/CT.","authors":"Haiqiong Zhang, Meixi Liu, Ximin Shi, Jiangyu Ma, Chao Ren, Zhenghai Huang, Ying Wang, Hongli Jing, Li Huo","doi":"10.1186/s40658-024-00677-5","DOIUrl":"https://doi.org/10.1186/s40658-024-00677-5","url":null,"abstract":"<p><strong>Purposes: </strong>To explore the clinical feasibility and efficacy of a deep inspiration breath-hold (BH) PET/CT using [¹⁸F]AlF-NOTA-LM3 on upper abdominal lesions in patients with neuroendocrine tumors (NETs).</p><p><strong>Methods: </strong>Twenty-three patients underwent a free-breath (FB) whole-body PET/CT, including a 10 min/bed scan for the upper abdomen with a vital signal monitoring for respiratory gating (RG) followed by a 20-second BH PET/CT covering the same axial range. For the upper abdomen bed, the following PET series was reconstructed: a 2-min FB PET; RG PET (6 bins); a 20-second and 15-second BH PET (BH_15 and BH_20). Semi-quantitative analysis was performed to compare liver SUV_mean, lesion SUV_max, MTV, its percentage difference and target-to-background ratio (TBR) between both BH PET and RG PET images. Subgroup analysis considered lesion location, MTV and SUV_max. A 5-point Likert scale was used to perform visual analysis and any missed or additional lesions were identified compared with RG PET.</p><p><strong>Results: </strong>Quantitative analysis on overall lesions (n = 78) revealed higher SUV_max and TBR, and smaller MTV for both BH PET compared to FB and RG PET, with lesion location-specific variations. Neither significant difference was observed in all metrics between RG and FB PET in larger lesions, nor in MTV in lower-uptake lesions. However, both BH PET significantly enhanced these measurements. In the visual analysis, both BH PET showed noninferior performance to RG PET, and were evaluated clinically acceptable. Additional and missed lesions were observed in FB and both BH PET compared with RG PET, but didn't alter the clinical management. The BH_15 PET showed comparable performance to BH_20 PET in any comparison.</p><p><strong>Conclusion: </strong>The BH PET/CT using [¹⁸F]AlF-NOTA-LM3 is effective in detecting upper abdominal lesions, offering more accurate quantitative measurements. Using a novel PET/CT scanner, a 15-second BH PET can provide comparable and superior performance to RG PET, indicating potential feasibility in clinical routines.</p>","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":"11 1","pages":"75"},"PeriodicalIF":3.0,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11362407/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142105488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and proof of concept of a double-panel TOF-PET system.","authors":"Andrea Gonzalez-Montoro, Noriel Pavón, Julio Barberá, Neus Cuarella, Antonio J González, Santiago Jiménez-Serrano, Alejandro Lucero, Laura Moliner, David Sánchez, Koldo Vidal, José M Benlloch","doi":"10.1186/s40658-024-00674-8","DOIUrl":"10.1186/s40658-024-00674-8","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Objective: &lt;/strong&gt;Positron Emission Tomography (PET) is a well-known imaging technology for the diagnosis, treatment, and monitoring of several diseases. Most PET scanners use a Ring-Shaped Detector Configuration (RSDC), which helps obtain homogeneous image quality but are restricted to an invariable Field-of-View (FOV), scarce spatial resolution, and low sensitivity. Alternatively, few PET systems use Open Detector Configurations (ODC) to permit an accessible FOV adaptable to different target sizes, thus optimizing sensitivity. Yet, to compensate the lack of angular coverage in ODC-PET, developing a detector with high-timing performance is mandatory to enable Time-of-Flight (TOF) techniques during reconstruction. The main goal of this work is to provide a proof of concept PET scanner appropriate for constructing the new generation of ODC-PET suitable for biopsy guidance and clinical intervention during acquisition. The designed detector has to be compact and robust, and its requirements in terms of performance are spatial and time resolutions &lt; 2 mm and &lt; 200 ps, respectively.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;The present work includes a simulation study of an ODC-PET based on 2-panels with variable distance. The image quality (IQ) and Derenzo phantoms have been simulated and evaluated. The phantom simulations have also been performed using a ring-shaped PET for comparison purposes of the ODC approach with conventional systems. Then, an experimental evaluation of a prototype detector that has been designed following the simulation results is presented. This study focused on tuning the ASIC parameters and evaluating the scintillator surface treatment (ESR and TiO&lt;sub&gt;2&lt;/sub&gt;), and configuration that yields the best Coincidence Time Resolution (CTR). Moreover, the scalability of the prototype to a module of 64 × 64mm&lt;sup&gt;2&lt;/sup&gt; and its preliminary evaluation regarding pixel identification are provided.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;The simulation results reported sensitivity (%) values at the center of the FOV of 1.96, 1.63, and 1.18 for panel distances of 200, 250, and 300 mm, respectively. The IQ reconstructed image reported good uniformity (87%) and optimal CRC values, and the Derenzo phantom reconstruction suggests a system resolution of 1.6-2 mm. The experimental results demonstrate that using TiO&lt;sub&gt;2&lt;/sub&gt; coating yielded better detector performance than ESR. Acquired data was filtered by applying an energy window of ± 30% at the photopeak level. After filtering, best CTR of 230 ± 2 ps was achieved for an 8 × 8 LYSO pixel block with 2 × 2 × 12mm&lt;sup&gt;3&lt;/sup&gt; each. The detector performance remained constant after scaling-up the prototype to a module of 64 &lt;math&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;/math&gt; 64mm&lt;sup&gt;2&lt;/sup&gt;, and the flood map demonstrates the module's capabilities to distinguish the small pixels; thus, a spatial resolution &lt; 2 mm (pixel size) is achieved.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;The simulated results of this biplanar scanner sh","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":"11 1","pages":"73"},"PeriodicalIF":3.0,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11341523/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142035469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}