EJNMMI Physics最新文献

{"title":"Multicenter comparison of radionuclide calibrators and SPECT/CT protocols for quantitative ¹⁷⁷Lu   imaging in clinical practice.","authors":"Wies Claeys, Kristof Baete, Laurence Beels, Claire Bernard, Rachele Danieli, Yves D'Asseler, An De Crop, Michel Hesse, Victor Nuttens, Bruno Vanderlinden, Michel Koole","doi":"10.1186/s40658-026-00877-1","DOIUrl":"https://doi.org/10.1186/s40658-026-00877-1","url":null,"abstract":"<p><strong>Purpose: </strong>Following the clinical success of [Formula: see text]-based therapies for neuroendocrine tumors and prostate cancer, accurate quantification of [Formula: see text]  using radionuclide calibrators (RNCs) and SPECT/CT is gaining importance as prerequisite for accurate treatment delivery and dosimetry. However, the lack of standardization can introduce inter-system variability, compromising multi-center clinical trials. This study aimed to assess the accuracy and variability of [Formula: see text]  measurements using RNCs and SPECT/CT across different systems and hospitals.</p><p><strong>Methods: </strong>A uniform cylindrical phantom and a NEMA phantom with hot spheres were prepared using traceable activities and imaged at 8 different hospitals using 13 SPECT/CT systems (9 conventional and 4 3D CZT). Acquisitions and reconstructions were performed using both site-specific and standardized protocols. The cylindrical phantom images were used to evaluate the system calibration and establish image calibration factors (ICFs), the NEMA images to evaluate effective resolution by calculating recovery coefficients (RCs). In parallel, two vials were measured to test RNC accuracy.</p><p><strong>Results: </strong>RNC measurements differed up to 11% between centers, while SPECT quantification of the cylindrical phantom differed up to 20%. While ICFs were consistent for systems of the same type, image quality varied strongly when using clinical protocols (36% difference in RCs in the largest sphere). Standardized reconstruction reduced variability in RCs for each system type (maximum 12% difference), regardless of acquisition protocol, but differences between system types persisted when standardizing acquisition and reconstruction (33% difference).</p><p><strong>Conclusion: </strong>Current [Formula: see text] measurement practices yield significant variability in quantification and image quality. Harmonization efforts should prioritize standardized calibration and reconstruction protocols to improve multicenter reproducibility of quantitative [Formula: see text]-SPECT/CT.</p>","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147835232","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":"Advancements in DOI-capable TOF-PET modules using a multi-channel high-frequency readout.","authors":"Giulia Terragni, Elena Tribbia, Joshua W Cates, Marco Pizzichemi, Johann Marton, Etiennette Auffray","doi":"10.1186/s40658-026-00870-8","DOIUrl":"https://doi.org/10.1186/s40658-026-00870-8","url":null,"abstract":"<p><strong>Purpose: </strong>The achievement of excellent coincidence time resolution has become an essential objective in time-of-flight positron emission tomography (TOF-PET) in order to improve the signal-to-noise ratio and the quality of the reconstructed image. Moreover, to achieve a high level of spatial resolution while maintaining good sensitivity with the use of long scintillators, the impact of the gamma-ray depth of interaction (DOI) must be mitigated.</p><p><strong>Methods: </strong>To address these challenges, a matrix of sixteen 20 mm-long LYSO:Ce scintillators with depolished lateral surfaces is used, coupled to a light guide that enables light sharing within the matrix. This configuration allows for the determination of the gamma-ray DOI and the correction of its timing bias. For this light-sharing method to work, readout integration in a multi-channel scheme is required. This is achieved using a sixteen-channel low-noise, low-power, high-frequency development circuit board. This high-frequency circuit also provides a solution to enhance the time resolution by enabling a lower leading-edge threshold for the detection of the earliest photons produced with high precision.</p><p><strong>Results: </strong>The DOI-capable module achieves a DOI resolution of 2.2 ± 0.2 mm full-width-at-half-maximum (FWHM) and a CTR of 133 ± 2 ps FWHM after DOI correction on the central crystals. For comparison, a standard module consisting of sixteen polished crystals and no back light guide achieves a CTR of 130 ± 2 ps FWHM.</p><p><strong>Conclusions: </strong>Using 20 mm-long LYSO:Ce crystals and this high-frequency electronics, the DOI-capable module delivers excellent timing and energy resolution. In addition to providing time resolution comparable to that of the standard module, it also allows DOI encoding with a resolution of nearly 2 mm FWHM.</p>","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147812587","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":"Uncertainty analysis of single-time-point organ dosimetry compared with the multi-time-point method in radioimmunotherapy.","authors":"Amit Nautiyal, Gemma Lewis, Jonathan I Gear, Kim Orchard, Matthew J Guy, Sofia Michopoulou","doi":"10.1186/s40658-026-00883-3","DOIUrl":"https://doi.org/10.1186/s40658-026-00883-3","url":null,"abstract":"<p><strong>Background: </strong>A position paper released by the European Association of Nuclear Medicine emphasised the need for multidisciplinary engagement to establish dosimetry-based personalised treatment in Radionuclide therapy (RNT). The uncertainty analysis results often ignored in routine clinical practice should be incorporated into the dose calculations to improve the efficacy and accuracy of treatment. In this study, patients with haematological malignancies undergoing radioimmunotherapy were evaluated. Our study aimed to calculate the uncertainties associated with each parameter of the single time point (STP) dosimetry chain and compare the with multiple time points (MTP) in the bone marrow and liver results.</p><p><strong>Methods: </strong>28 patients received an intravenous injection of ¹¹¹In-besilesomab (0.17 ± 0.01GBq) for pre-therapeutic dosimetry and were subsequently treated with ⁹⁰Y-besilesomab(2.43 ± 0.53GBq). A dosimetry analysis was performed on bone marrow (BM) and liver with MTP and STP. We investigated the uncertainty in population mean effective half-life, volume, recovery coefficient, counts, measured activity, fitting parameters, time-integrated-activity, S-factors, and absorbed dose (AD) for a group of patients.</p><p><strong>Results: </strong>The mean absorbed dose per unit administered activity (DpA) to BM was 5.8 ± 1.7 mGy/MBq with MTP and 5.8 ± 1.6 mGy/MBq with STP, and to the liver was 2.9 ± 1.9 mGy/MBq with MTP and 3.1 ± 2.4 mGy/MBq with STP. The mean fractional uncertainty associated with total absorbed dose to BM was 13.18 ± 3.46% with MTP and 18.75 ± 3.22% with STP, and to liver was 5.77 ± 3.13% with MTP and 49.78 ± 25.36% with STP. A moderate positive relationship (R² = 0.7) was noted between post-injection acquisition time and AD uncertainty with STP for BM, whereas a strong positive relationship (R² = 1) was noted for the liver.</p><p><strong>Conclusion: </strong>The absorbed dose uncertainty in STP was significantly higher compared to the MTP. Incorporating the uncertainty analysis for STP dosimetry parameters in routine clinical practice is strongly recommended. The accuracy in the acquisition time, population-based half-life and fitting function for time activity curve is vital for minimising uncertainty in STP dosimetry, which is less time-consuming and easier to implement in clinical practice than MTP.</p>","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147812535","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":"The impact of motion correction on quantitatively measured perfusion indices using cardiac-dedicated dynamic CZT-SPECT myocardial perfusion imaging.","authors":"Ajay Kumar Chaudhary, Fukai Zhao, Zekun Pang, Jianming Li","doi":"10.1186/s40658-026-00881-5","DOIUrl":"https://doi.org/10.1186/s40658-026-00881-5","url":null,"abstract":"","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147766203","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":"Q.Clear reconstruction shortening the scanning time for ¹¹C-CFT brain PET/MR imaging.","authors":"Leiyue Chen, Wenjie Gong, Dan Wang, He Long, Xin Li, Renxiang Xia, Yun Yao, Wen Zhou, Weicheng Zhou, Xiao Chen","doi":"10.1186/s40658-026-00878-0","DOIUrl":"https://doi.org/10.1186/s40658-026-00878-0","url":null,"abstract":"","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147766173","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":"AI-based synthetic CT attenuation correction enables reliable quantitative SPECT in unilateral condylar hyperplasia.","authors":"Anna Rebeka Kovács, Enikő Fanni Juhász, Péter Czina, Ádám Budai, József Varga, Borbála Husztik, Ákos Kovács, Melinda Szoliková, Róbert Boda, Kincső Sára Kovács, Ildikó Garai, Sándor Kristóf Barna","doi":"10.1186/s40658-026-00879-z","DOIUrl":"https://doi.org/10.1186/s40658-026-00879-z","url":null,"abstract":"<p><strong>Purpose: </strong>Unilateral condylar hyperplasia (UCH) is a rare mandibular growth disorder in which accurate assessment of condylar metabolic activity is essential for surgical decision-making. Quantitative ^99mTc-methylene diphosphonate (MDP) SPECT/CT is commonly used for this purpose; however, CT-based attenuation correction (CTAC) increases radiation exposure and may be affected by registration errors. Artificial intelligence (AI)-generated synthetic CT (SyCT) has been proposed as a CT-independent alternative. This study aimed to evaluate the agreement between SyCT-based attenuation correction (SyCTAC) and conventional CTAC in quantitative SPECT imaging of UCH.</p><p><strong>Methods: </strong>This retrospective study included 14 patients with UCH who underwent ^99mTc-MDP SPECT/CT. SPECT images were reconstructed with identical parameters using either CTAC or AI-generated SyCTAC. Spherical volumes of interest were placed over both mandibular condyles and the clivus, and maximum and mean standardized uptake values were measured. Relative uptake fractions normalized to the summed condylar activity were calculated for the affected side, while condylar uptake normalized to the clivus was evaluated for both sides. Agreement between CTAC- and SyCTAC-derived indices was assessed using Bland-Altman analysis and linear mixed-effects models.</p><p><strong>Results: </strong>Visual evaluation revealed no relevant differences in image quality between the two reconstructions. Relative uptake fractions normalized to the summed condylar activity showed good agreement between methods. Clivus-normalized ratios demonstrated a small positive bias.</p><p><strong>Conclusion: </strong>AI-generated SyCT provides attenuation correction comparable to CTAC for clinically relevant relative condylar uptake assessment in UCH, supporting its use as a low-radiation alternative for quantitative mandibular SPECT imaging.</p>","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147728649","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":"Effective elimination of respiratory misregistration-induced attenuation correction errors in PET/CT via deep learning trained on data-driven gated PET from strictly respiratory-phase-matched PET/CT cases.","authors":"Koki Takamura, Koichi Ishizu, Chio Okuyama, Tomohiro Ueno, Naozo Sugimoto","doi":"10.1186/s40658-026-00880-6","DOIUrl":"https://doi.org/10.1186/s40658-026-00880-6","url":null,"abstract":"","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147722225","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":"Design and first experimental results of an edgeless PET prototype for breast imaging: DeepBreast.","authors":"Marta Freire, Santiago Jiménez-Serrano, Andrea Gonzalez-Montoro, Francisco B García, José F Toledo, Julio Barberá, Jorge Álamo, Irene Torres-Espallardo, Luis F Vidal, Francis Loignon-Houle, Carlos de Alfonso, Sara Echegoyen, María J Rodríguez-Álvarez, Filomeno Sánchez, Antonio J González","doi":"10.1186/s40658-026-00869-1","DOIUrl":"https://doi.org/10.1186/s40658-026-00869-1","url":null,"abstract":"<p><strong>Background: </strong>Breast cancer causes the largest number of cancer-related deaths among women worldwide. With the aim of improving Positron Emission Tomography (PET) technology for accurate breast cancer diagnosis and staging, we propose a system design based on monolithic crystals with inherent Depth of Interaction (DOI) capabilities and an innovative edgeless detector ring. This approach eliminates the physical gaps between PET detectors, improving the system detection efficiency while potentially enhancing the image quality since edge effects are reduced. We have developed a dedicated breast PET system prototype (DeepBreast) to show the feasibility of this design. The system is composed of 14 curved LYSO monolithic scintillators of 12.5 mm thickness glued side-by-side with a high-refractive index compound. The useful transaxial and axial Field of View (FOV) of the system are 160 mm and 50 mm, respectively. A Neural Network technique was used for the x- and y- photon impact position estimation. The impact DOI and energy values were determined using the Voronoi calibration methodology. An initial experimental evaluation of the DeepBreast system has been performed inspired by the NEMA protocols for whole-body and small-animals PET scanners.</p><p><strong>Results: </strong>A nearly flat spatial resolution as a function of radial position was obtained, which indicates the DOI capability of the system to mitigate parallax errors. An average spatial resolution of 1.9 ± 0.1 mm, 1.9 ± 0.1 mm and 1.7 ± 0.1 mm FWHM was achieved at the center of the axial FOV for the radial, tangential, and axial directions, respectively. A maximum sensitivity value of 2% was measured at the center of the FOV. The noise equivalent count rate peak reached 15 kcps at 13.4 MBq. Moreover, percent contrast values of 27.9%, 28.8%, 56.8%, 72.5%, 87.2% and 84.2% were achieved for 4.5 mm, 6 mm, 9 mm, 12 mm, 15 mm and 20 mm cylinders of a larger dedicated IQ phantom, respectively.</p><p><strong>Conclusions: </strong>The initial experimental results demonstrate the feasibility of the DeepBreast as an innovative PET scanner for breast cancer imaging.</p>","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147697844","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":"Gravity versus pump-driven infusion in targeted radionuclide therapy: a model-based dosimetric evaluation of extravasation.","authors":"Olivia Lienhardt, Oreste Allegrini, Nathan Poterszman, Florian Ritzenthaler, Clémence Porot, Christophe Mazzara, Francois Somme, Julien Salvadori","doi":"10.1186/s40658-026-00852-w","DOIUrl":"https://doi.org/10.1186/s40658-026-00852-w","url":null,"abstract":"<p><strong>Background: </strong>Intravenous administration of [Formula: see text]Lu-labeled radiopharmaceuticals (RPMs) such as PSMA and DOTATATE entails a risk of extravasation, potentially resulting in absorbed doses exceeding thresholds for deterministic tissue damage. Gravity-driven and pump-assisted infusion methods differ in dilution and flow dynamics, which directly affect the extravasated dose. This study aimed to extend and validate an analytical model for quantitative comparison of extravasation-related dosimetric risks between both strategies and to inform clinical protocol optimization.</p><p><strong>Methods: </strong>A previously published analytical model for gravity-driven delivery was extended to pump-assisted infusion by incorporating method-specific dilution kinetics within the mixing compartment and laminar (Poiseuille) flow through the infusion line and venous system. Extravasation was modeled mechanistically to estimate extravasated activity, concentration, and equivalent dose rate (EDR) at the injection site. Model validation was performed by comparing simulated EDRs with in vivo measurements from 28 clinical [Formula: see text]Lu-PSMA infusions using the ED3 bilateral dosimetry system. Simulations covered clinically relevant parameter ranges, and absorbed doses were derived by combining simulated concentrations with Monte Carlo-based S-values, assuming an effective residence time of 1.5 h supported by clinical SPECT/CT data.</p><p><strong>Results: </strong>The model reproduced measured EDR kinetics with a mean deviation of 16 % during infusion. Gravity-driven infusions generated steep concentration peaks in case of early extravasation, with absorbed dose strongly dependent on onset timing. Pump-assisted delivery yielded stable profiles largely independent of onset. Across clinical parameter ranges, gravity-based protocols produced extravasated concentrations of 155-345 [Formula: see text] and doses of 30-68 Gy, with mitigation relying on vial pre-dilution at the cost of prolonged infusion times. Pump-assisted protocols allowed safer modulation (21-180 [Formula: see text], 4-35 Gy) through independent control of RPM and saline flow rates, without vial dilution. For equivalent infusion durations (e.g., 44 min), pump delivery achieved extravasated doses and concentrations about sevenfold lower than gravity (5.2 vs. 35 Gy), supporting its clinical value for protocol optimization and radioprotection.</p><p><strong>Conclusion: </strong>We present an analytical model for estimating absorbed dose in the event of extravasation during [Formula: see text]Lu-RPM infusion. The results highlight the decisive safety benefits of pump-assisted administration over gravity-driven delivery and support its implementation as a proactive strategy to minimize extravasation risk, improve patient safety, and harmonize therapeutic protocols across centres .</p>","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147697841","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":"Multi-site distributed training with data protections for PET-based synthetic CT.","authors":"Kasper Jørgensen, Lauren Partin, Raghavan Ashok, Vijay Shah, Anders Bertil Rodell, Martin Bazik, Bruce Spottiswoode, Flemming Littrup Andersen","doi":"10.1186/s40658-026-00868-2","DOIUrl":"https://doi.org/10.1186/s40658-026-00868-2","url":null,"abstract":"","PeriodicalId":11559,"journal":{"name":"EJNMMI Physics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147688933","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}