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Performance characteristics of the digital Biograph Vision PET/CT system
摘要： This study evaluates the performance of the Siemens Biograph Vision digital PET/CT system (Siemens Healthineers, Knoxville, USA) according to the NEMA NU 2‐2012 standard (published by the National Electrical Manufacturers Association (NEMA)) to allow for a reliable, reproducible, and inter‐system comparable performance measurement. Methods: The new digital PET/CT features silicon photomultiplier (SiPM)‐based detectors with 3.2 mm lutetium oxyorthosilicate (LSO) crystals and full coverage of the scintillator area. The PET components incorporate eight rings of 38 detector blocks and each block contains 4x2 mini‐blocks. Each mini‐block consists of a 5x5 LSO‐array of 3.2x3.2x20 mm crystals coupled to a SiPM‐array of 16x16 mm, resulting in an axial field of view (FOV) of 26.1 cm. In this study PET/CT system performance will be evaluated conform the NEMA NU 2‐2012 standard with additional measurements described in the new NEMA NU 2‐2018 standard. Spatial resolution, sensitivity, count‐rate performance, accuracy of attenuation and scatter correction, Time‐of‐Flight (TOF) performance, and image quality will be determined. Measurements will be directly compared to results from its predecessor, the Biograph mCT Flow, using existing literature. Moreover, feasibility to comply with the European Association of Nuclear Medicine (EANM) Research Ltd (EARL) criteria will be evaluated and some illustrative patient PET images will be shown. Results: The Biograph Vision shows a transverse (resp. axial) spatial resolution at Full Width Half Maximum (FWHM) of 3.6 mm (resp. 3.5 mm) at 1 cm offset of the center of the FOV (measured with a 22Na 0.25 mm point‐source), a NEMA sensitivity of 16.4 kcps/MBq, and a NEMA peak NECR of 306 kcps at 32 kBq/mL. TOF resolution varied from 210 to 215 as count‐rate increased up to the peak NECR. The overall image contrast seen with the NEMA image quality phantom ranged from 77.2% to 89.8%. Furthermore, the system was able to comply with the current and future EARL performance criteria. Conclusions: The Biograph Vision outperforms the analog Biograph mCT Flow and the system is able to meet European harmonizing performance standards.
关键词： PET/CT,Digital detectors,NEMA,performance evaluation
更新于2025-09-23 15:22:29
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18F-FDG PET/TC para la estadificación y la delineación del volumen de radioterapia en el cáncer de cabeza y cuello
摘要： Purpose: The aim is to investigate the use of 18F-FDG (fluorine-18 fluorodeoxyglucose) PET/CT in head and neck cancer (HNC) staging and its effect on the therapeutic strategy and radiotherapy (RT) planning. Methods and materials: One hundred patients with HNC were included. Primary tumor sites: 18% oral cavity, 20% oropharynx, 12% hypopharynx, 11% nasopharynx, 37% larynx, 2% paranasal sinuses. Patients were staged according to the American Joint Committee of Cancer 7th edition. Stage: 5% stage I, 7% stage II, 14% stage III, 61% stage IVA, 7% stage IVB and 6% stage IVC. A contrast-enhanced CT and a 18F-FDG PET/CT acquired under RT position were performed. Both exams were compared to analyze patients' staging reclassification. Changes in therapeutic strategy were analyzed. Results: 18F-FDG PET/CT detected 6 distant metastases and treatment intention changed to palliative. Eight synchronous tumors were detected; one received palliative treatment. 18F-FDG PET/CT reclassified cTNM staging in 27 patients. Tumor extension changed in 28 (14% up-staged; 14% down-staged), implying a change in GTV (Gross Tumor Volume) delineation. Nodal detection was reclassified in 47 patients: 8 patients down-staged (N2C to N2A/N2B/N1) and 2 were false positive. Nineteen patients were false negatives and 5 staged as N+ (N1/N2A/N2B) turned out into N2C. These staging modifications imply adapting the nodal volume to be irradiated. Conclusions: 18F-FDG PET/CT reclassification was higher than 10% in almost all categories studied (cTNM, tumor extension and nodal disease) and detects more metastases and synchronous tumors than conventional studies, which has an impact on the therapeutic patient management and RT planning.
关键词： Head and neck cancer,18F-FDG PET/CT,Radiotherapy planning,Staging
更新于2025-09-23 15:22:29
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Primary Pulmonary Low-Grade Angiosarcoma Characterized by Mismatch between <sup>18</sup> F-FDG PET and Dynamic Contrast-Enhanced CT
摘要： We report a rare case of primary pulmonary low-grade angiosarcoma on dynamic contrast-enhanced CT and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT imaging. A 38-year-old, asymptomatic woman was hospitalized because of an abnormality on chest radiography. A dynamic contrast-enhanced chest CT showed a 1.2 cm-sized irregular-margined nodule with strong and persistent enhancement in the right lower lobe. The lesion had low metabolic activity on an 18F-FDG PET/CT scan. The patient underwent a wedge resection for the lesion, and pathology revealed a primary pulmonary low-grade angiosarcoma.
关键词： Primary pulmonary angiosarcoma,Dynamic contrast-enhanced CT,Low-grade,18F-FDG PET/CT
更新于2025-09-23 15:22:29
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18F-FDG uptake in the normal appendix in adults: PET/CT evaluation
摘要： Objective This study aimed to determine the level of 18F fluorodeoxyglucose (18F-FDG) activity in the normal adult appendix using positron emission tomography/computed tomography (PET/CT). Materials and methods We performed a retrospective review of PET/CT images using 18F-FDG in 563 consecutive asymptomatic adult patients without appendiceal pathology. We excluded 257 patients for an undetected or obscured appendix and three patients for appendicitis found on CT imaging. FDG uptake in the appendix was qualitatively and quantitatively assessed. The maximum standardized uptake value (SUVmax) was calculated for quantitative analysis with SUVmax of the normal liver for comparison. A total of 303 patients (200 males, 103 females, mean age of 66 years) were included in this study. Medical charts and histories were evaluated for patients who showed positive FDG accumulation. Pearson’s correlations between appendiceal SUVmax and age, body mass index, and blood glucose levels were analyzed. Results The mean appendiceal SUVmax was 1.14 (range 0.52–5.12) with an appendix-to-liver SUVmax ratio of 0.34 (range 0.06–1.28). Three patients qualitatively showed a positive FDG accumulation with appendiceal SUVmax greater than 3.00. There were no correlations between appendiceal SUVmax and age, body mass index, or blood glucose levels. Conclusions FDG in the normal adult appendix shows a low activity level and is lower compared with normal liver. However, the normal appendix can rarely show high FDG accumulation. In such cases, differentiation from appendiceal pathology solely by PET/CT images would be difficult.
关键词： Normal variants,Adult,PET/CT,Appendix
更新于2025-09-23 15:22:29
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Eficacia de la imagen precoz con 68Ga-PSMA-I&T para la discriminación de lesiones en los pacientes con cáncer de próstata
摘要： Objective: 68Ga-PSMA-uptake shows accumulation in the malignant lesions of prostate cancer patients as early as 5 min p.i. Studies indicate the value of adding an early image of the pelvis to the imaging protocol of 68Ga-PSMA-11 PET/CT scan showed contradictory results. In this study we planned to assess the significance of an additional early imaging in 68Ga-PSMA-I&T PET/CT imaging in prostate cancer patients. Materials and methods: A total of 35 prostate cancer patients referred to 68Ga-PSMA-I&T PET/CT imaging for restaging of the disease due to suspicion of relapse after definitive therapy were enrolled. First an early static pelvic image was obtained at a maximum of 300 s following injection of the radiotracer. Sixty minutes postinjection a whole-body PET/CT scan was conducted with an emission time of 3 min per bed position. The lesions which were categorized as local recurrence, bone lesion and lymph node metastasis in the early images, were compared with the late images in terms of number of lesions detected and SUVmax values. Results: 68Ga-PSMA-I&T PET/CT was positive in 23 of 35 patients (65.7%). A pathological uptake was observed in the prostatic bed site, in the pelvic lymph nodes, and in the bones in 17 patients (48.5%), 12 patients (34.2%), and 13 patients (37.1%), respectively. In one patient, focal pathological increased uptake in the prostatic bed with a SUVmax value of 5.8 was detected but this lesion disappeared in the late images. The average SUVmax values of the lesions in the prostatic bed were 13.7 ± 12.1 versus 26.3 ± 23.8 in the 5 min and 60 min studies respectively (p < 0.001). In one patient, the pathological uptake in the lymph node in the early study cleared in the late study, whereas in another accumulation of activity was detected in a pelvic lymph node in the late study, while there was no lymph node detected in the early study. The average SUVmax values of the lymph nodes were 12.1 ± 8.8 versus 26.3 ± 22.6 in the 5 min and 60 min studies respectively (p < 0.001). The average SUVmax values of the bone lesions were 11.4 ± 6.9 versus 15 ± 10.7 in the 5 min and 60 min studies respectively. Conclusion: Our study is the first in the literature to evaluate the impact of adding an early static pelvic image to the 68Ga-PSMA-I&T scan, in the detection rate of the lesions. Although there was no marked discordance between the 2 sets of images, the addition of an early image to the imaging protocol of 68Ga-PSMA-I&T scan would increase the efficacy of detection of malignant lesions in the pelvis, which might show rapid clearance and has the risk of being masked by the urinary system activity.
关键词： Prostate-specific membrane antigen,68Ga-PSMA-I&T,PET/CT,Lymph node metastases,Prostate cancer
更新于2025-09-23 15:22:29
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Integrin α <sub/>γ</sub> β <sub/>3</sub> -targeted [ <sup>64</sup> Cu]CuS Nanoparticles for PET/CT Imaging and Photothermal Ablation Therapy
摘要： Copper sulfide (CuS) nanoparticles have been considered one of the most clinical relevant nanosystems because of their straightforward chemistry, small particle size, low toxicity, and intrinsic theranostic characteristics. In our previous studies, radioactive [64Cu]CuS nanoparticles were successfully developed to be used as efficient radiotracers for positron emission tomography and for photothermal ablation therapy of cancer cells using near-infrared laser irradiation. However, the major challenge of CuS nanoparticles as a theranostic platform is the lack of a means for effective targeted delivery to the tumor site. To overcome this challenge, we designed and synthesized angiogenesis-targeting [64Cu]CuS nanoparticles, which are coupled with cyclic RGDfK peptide [c(RGDfK)] through polyethylene glycol (PEG) linkers using click chemistry. In assessing their tumor-targeting efficacy, we found that the tumor uptakes of [64Cu]CuS-PEG-c(RGDfK) nanoparticles at 24 h after intravenous injection were significantly greater (8.6%±1.4% injected dose/gram of tissue) than those of nontargeted [64Cu]CuS-PEG nanoparticles (4.3%±1.2% injected dose/gram of tissue, p < 0.05). Irradiation of tumors in mice administered [64Cu]CuS-PEG-c(RGDfK) nanoparticles induced 98.7% necrotic areas. In contrast, irradiation of tumors in mice administered non-targeted CuS-PEG nanoparticles induced 59% necrotic areas (p < 0.05). The angiogenesis-targeting [64Cu]CuS nanoparticles may serve as a promising platform for image-guided ablation therapy with high efficacy and minimal side effects in future clinical translation of this novel class of multifunctional nanomaterials.
关键词： PET/CT imaging,RGD peptide,Copper sulfide nanoparticles,photothermal ablation therapy,integrin αvβ3,theranostics
更新于2025-09-23 15:21:21
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Characterization of monolithic GAGG:Ce coupled to both PMT and SiPM array for gamma imaging in Nuclear Medicine
摘要： GaGG:Ce scintillation crystal is very useful for nuclear imaging purposes, thanks to its several advantages (high density, short decay time, high light yield and good energy resolution, no self-activity, no hygroscopic). However, only the recent improvements in the growth processes make it available with large size, in order to use it in monolithic configuration. The main drawbacks of pixelated crystals, as non-uniform response, high production costs and optical light loss, could be therefore overcome. In this work the characterization of this promising crystal coupled both to a single channel PMT (spectrometric purpose) and to a new technology SiPM (50% PDE and 74% geometrical fill factor) has been performed. The detection efficiency results good both for SPECT (87% at 122 keV) and for PET (18% at 356 keV) applications. However, the unexpected result arises from the energy resolution: at 356 keV 8.9% and 8.0% for single channel PMT and SiPM configuration, respectively. In other terms, the used SiPM allows to achieve higher energy resolution than single channel PMT. Moreover, a high imaging performance has been observed, with a millimeter intrinsic spatial resolution.
关键词： SPECT,PET PET/CT,Gamma camera,Intra-operative probes,Scintillators and scintillating fibres and light guides,coronary CT angiography (CTA),Scintigraphy and whole-body imaging
更新于2025-09-23 15:21:01
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Optimized feature extraction for radiomics analysis of <sup>18</sup> F-FDG-PET imaging
摘要： Radiomics analysis of 18F-FDG-PET/CT images promises for an improved in-vivo disease characterization. To date, several studies reported significant variations in textural features due to differences in patient preparation, imaging protocols, lesion delineation and feature extraction. Our objective was to study variations of features prior to a radiomics analysis of 18F-FDG-PET data and to identify those feature extraction and imaging protocol parameters that minimize radiomic feature variations across PET imaging systems. Methods. A whole-body National Electrical Manufacturers Association image quality phantom was imaged with 13 PET/CT systems at 12 different sites following local protocols. We selected 37 radiomic features related to the four largest spheres (17-37 mm) in the phantom. Based on a combined analysis of voxel size, bin size and lesion volume changes, feature and imaging system ranks were established. A 1-way analysis of variance (ANOVA) was performed over voxel size, bin size and lesion volume subgroups to identify the dependency and the trend change of feature variations across these parameters. Results. Feature ranking revealed that the gray-level co-occurrence matrix (GLCM) and shape features are the least sensitive to PET imaging system variations. Imaging system ranking illustrated that the use of point-spread function (PSF), small voxel sizes and narrow Gaussian post-filtering helped minimize feature variations. ANOVA subgroup analysis indicated that variations of each of the 37 features and for a given voxel size and bin size parameter can be minimized. Conclusions. Our study provides guidance to selecting optimized features from 18F-FDG-PET/CT studies. We were able to demonstrate that feature variations can be minimized for selected image parameters and imaging systems. These results can help imaging specialists and feature engineers in increasing the quality of future radiomic studies involving PET/CT.
关键词： radiomics,18F-FDG PET/CT,feature extraction
更新于2025-09-23 15:21:01
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AN INTERNATIONAL SURVEY ON CLINICAL REPORTING OF DUAL-MODALITY PET/CT IMAGING EXAMINATIONS: A STARTING POINT FOR CROSS-SPECIALTY ENGAGEMENT
摘要： Introduction. Combined PET/CT imaging has become an integral part of patient management, particularly in oncology. Following the imaging examination, a report of the findings is created by the expert readers and sent to the referrers as a basis for subsequent management decision-making for their patients. In view of the known wide variation in operational models of PET/CT imaging, we initiated a survey of PET/CT users regarding their approaches towards PET/CT reporting. Materials and Methods. An electronic survey was composed with a set of 28 questions regarding the demographics and professional background of the survey responders, as well as questions regarding the structure and quality of PET/CT reports, including the type of reported information, the use of reporting standards and the mix of reporting and presenting experts. The survey was active during six weeks in early 2018. A total of 242 responses were collected worldwide. Results. The responders were mainly from Europe (78%), Of all responders, 21% were nuclear medicine specialists, 41% were radiologists, 22% were dual-board certified, 9% were residents in either nuclear medicine or radiology, and 5% were medical physicists, radiographers or oncologists. A slim majority (55%) of responses indicated reports being done according to the EANM/SNMMI 2015 guidelines for 18F-FDG-PET/CT imaging but 30% responders were unaware of these guidelines. Report structures varied across sites with most sites (38%) reporting the PET with supplementary localization information from CT, while 27% sites report along the lines of a CT report with supplementary PET information. One third of the reports include information on the TNM stage of the oncology patient in all reports, while 34% and 12% reports include this information occasionally or only for selected tumors, respectively. In case of therapy response assessment, various well-established criteria are employed ranging from 15% (EORTC) to 57% (Deauville) of cases. Conclusions. Broad variation in the PET/CT reporting strategies adopted for oncology studies and widespread lack of awareness of existing guidelines for PET/CT reporting are evident from responses to this survey, raising concerns as to whether reporting clinicians are optimally utilizing the complementary information from each modality. Greater efforts are needed to ensure harmonization of reporting practices.
关键词： clinical routine,PET/CT imaging,reporting
更新于2025-09-23 15:21:01
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Quantitative assessment of metabolic tumor burden in molecular subtypes of primary breast cancer with FDG PET/CT
摘要： We aimed to quantitatively evaluate volumetric metabolic tumor burden including metabolic tumor volume and total lesion glycolysis in different molecular subtypes of breast cancer using 18F-fluorodeoxyglucose (FDG) positron emission tomography/ computed tomography (PET/CT). This study involved 99 female patients with pathologic diagnosis of primary breast cancer, who underwent 18F-FDG PET/CT before any therapy. Patients were divided into subtypes of luminal A, luminal B, ERBB2+, and basal-like based on the immunohistochemistry results. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) before and after correction for lean body mass were achieved and compared. Correlations between metabolic tumor burden and Ki-67 were analyzed and diagnostic performances of volumetric metabolic parameters were evaluated. TLG values were significantly different between each molecular subtype, while MTV values were not. Values of TLG were significantly reduced after normalizing for lean body mass in each subtype. Both of them showed correlations with Ki-67 and presented high diagnostic ability in identifying patients with basal-like breast cancer from the rest. TLGs before and after normalizing for the lean body mass had similar diagnostic performances in differentiating patients of basal-like subtype from the rest. Metabolic tumor burden could comprehensively reflect tumor metabolic differences of molecular subtypes of breast cancer, and it can serve to help differentiate patients with basal-like breast cancer.
关键词： metabolic tumor burden,FDG PET/CT,breast cancer,volumetric parameters,molecular subtypes
更新于2025-09-23 15:21:01