In retrospective studies, 68 Ga-PSMA-11 positron emission tomographic (PET) imaging improves detection of biochemically recurrent prostate cancer compared with conventional imaging. OBJECTIVE To assess 68 Ga-PSMA-11 PET accuracy in a prospective multicenter trial.

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The study aims to investigate the presence of physiologic prostate-specific membrane antigen (Ga-PSMA)-ligand uptake on PET in cervical, celiac, and sacral ganglia of the sympathetic trunk as a pitfall for lymph node metastases in prostate cancer imaging. Four hundred seven patients who underwent Glu-NH-CO-NH-Lys radiolabeled withGa-gallium -bis[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine--diacetic acid (Ga-PSMA-HBED-CC) PET (combined with a diagnostic CT) were retrospectively analyzed. The number of Ga-PSMA PET-positive cervical, celiac, and sacral ganglia was determined, and the configuration and SUV of each ganglion were measured. In addition, the configuration and SUV of adjacent lymph node metastases in the respective region (cervical, celiac, or sacral) were determined. Ga-PSMA-ligand uptake above background was detected in 401 (98.5%) patients in any peripheral ganglia, in 369 (92%) patients in cervical ganglia, in 363 (89%) patients in celiac ganglia, and in 183 (46%) patients in sacral ganglia. TheGa-PSMA-ligand uptake was highest in celiac (mean SUV, 2.9 ± 0.8 vs. cervical mean SUV, 2.4 ± 0.6) and sacral (mean SUV 1.7 ± 0.5; both < 0.0001) ganglia. Intraindividually there was a statistically significant but weak to moderate correlation between the Ga-PSMA-ligand uptake in cervical versus celiac ganglia ( = 0.34, < 0.0001), cervical versus sacral ( = 0.52, < 0.0001), and celiac versus sacral ( = 0.16, < 0.05). The Ga-PSMA-ligand uptake was significantly more intense in adjacent lymph node metastases than the respective ganglia (cervical: 18.0 ± 16.2 vs. 2.4 ± 0.6, < 0.0001; celiac: 13.5 ± 12.3 vs. 2.9 ± 0.8, < 0.0001; sacral: 13.4 ± 11.6 vs. 1.7 ± 0.5, < 0.0001). Furthermore, ganglia predominantly exhibit a band-shaped configuration (71.2%), followed by a teardrop (26.8%) and only rarely a nodular configuration (2.0%). Conversely, lymph node metastases are only rarely band-shaped (1.1%), but more often show teardrop (40.3%) or nodular appearance (58.6%) ( < 0.00001). Ga-PSMA-ligand uptake in ganglia along the sympathetic trunk as assessed byGa-PSMA-HBED-CC PET represents an important pitfall in prostate cancer PET imaging. The Ga-PSMA-ligand uptake is higher in celiac ganglia than cervical or sacral ganglia, and the level ofGa-PSMA-ligand uptake seems to be patient-related. For the differentiation between lymph node metastases and sympathetic ganglia, both intensity of Ga-PSMA-ligand uptake and exact localization and configuration of the respective lesion should be examined carefully.

The interobserver agreement for Ga-PSMA-11 PET/CT study interpretations in patients with prostate cancer is unknown.Ga-PSMA-11 PET/CT was performed in 50 patients with prostate cancer for biochemical recurrence ( = 25), primary diagnosis ( = 10), biochemical persistence after primary therapy ( = 5), or staging of known metastatic disease ( = 10). Images were reviewed by 16 observers who used a standardized approach for interpretation of local (T), nodal (N), bone (Mb), or visceral (Mc) involvement. Observers were classified as having a low (<30 prior Ga-PSMA-11 PET/CT studies; = 5), intermediate (30-300 studies; = 5), or high level of experience (>300 studies; = 6). Histopathology ( = 25, 50%), post-external-beam radiation therapy prostate-specific antigen response ( = 15, 30%), or follow-up PET/CT ( = 10, 20%) served as a standard of reference. Observer groups were compared by overall agreement (% patients matching the standard of reference) and Fleiss' κ with mean and corresponding 95% confidence interval (CI). Agreement among all observers was substantial for T (κ = 0.62; 95% CI, 0.59-0.64) and N (κ = 0.74; 95% CI, 0.71-0.76) staging and almost perfect for Mb (κ = 0.88; 95% CI, 0.86-0.91) staging. Level of experience positively correlated with agreement for T (κ = 0.73/0.66/0.50 for high/intermediate/low experience, respectively), N (κ = 0.80/0.76/0.64, respectively), and Mc staging (κ = 0.61/0.46/0.36, respectively). Interobserver agreement for Mb was almost perfect irrespective of prior experience (κ = 0.87/0.91/0.88, respectively). Observers with low experience, when compared with intermediate and high experience, demonstrated significantly lower median overall agreement (54% vs. 66% and 76%, = 0.041) and specificity for T staging (73% vs. 88% and 93%, = 0.032). The interpretation of Ga-PSMA-11 PET/CT for prostate cancer staging is highly consistent among observers with high levels of experience, especially for nodal and bone assessments. Initial training on at least 30 patient cases is recommended to ensure acceptable performance.

Learning Objectives: On successful completion of this activity, participants should be able to describe (1) advantages and shortcomings of hybrid PET/MR scanners with respect to cardiovascular applications (e.g. myocardial perfusion imaging and viability imaging), (2) additional value of the MR component in cardiac imaging, and (3) technical challenges and workflow considerations regarding hybrid PET/MR scanners in the field of cardiology (e.g. attenuation correction and cardiac/respiratory/patient motion).Financial Disclosure: Dr. Schwaiger is an investigator, meeting participant, and lecturer for Siemens Medical. The authors of this article have indicated no other relevant relationships that could be perceived as a real or apparent conflict of interest. CME Credit: SNMMI is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to sponsor continuing education for physicians. SNMMI designates each JNM continuing education article for a maximum of 2.0 AMA PRA Category 1 Credits. Physicians should claim only credit commensurate with the extent of their participation in the activity. For CE credit, participants can access this activity through the SNMMI Web site (http:// www.snmmi.org/ce_online) through March 2016.PET/CT and other combined scanners have in the past decade rapidly emerged as important research tools and are proving to be invaluable for improved diagnostics in routine nuclear medicine. The design of hybrid PET/MR scanners presented a formidable technical challenge, and only recently were these instruments introduced to the market. Initial expectations of the performance of these scanners have been high, notably because of the potential for superior tissue contrast inherent in the MR modality, as well as the potential for multiparametric functional imaging in conjunction with PET. However, the additional value and potential clinical role that these new systems might bring to the cardiac field have yet to be documented. This review presents a comparative summary of the existing applications for PET and MR in the field of cardiology and suggests potential cardiac applications exploiting unique properties of the newly introduced combined instrumentation. The diverse range of imaging modalities for cardiology includes echocardiography, CT, MR imaging, SPECT, and PET, each of which offers distinct properties and advantages. The demand for combined PET/CT instrumentation in clinical nuclear medicine has grown remarkably, because of the notable advantages presented by hybrid imaging with respect to anatomic localization of lesions. Although these advantages were initially driven by the demands of oncology imaging, the resultant broader availability of PET/CT has provided the opportunity to use these scanners for indications beyond oncology, such as in the field of cardiac imaging (1). Furthermore, CT images are necessary for rapid attenuation correction, which is of particular importance for quantification in myocardial perfusion imaging. Through the use of suitable CT components a...

Introduction: Fibroblast activation protein (FAP) is overexpressed in several solid tumors and therefore represents an attractive target for radiotheranostic applications. Recent investigations demonstrated rapid and high uptake of small-molecule inhibitors of FAP ( 68 Ga-FAPI-46) for PET imaging. Here, we report our initial experience in terms of feasibility and safety of 90 Y-labelled FAPI-46 ( 90 Y-FAPI-46) for radioligand therapy (RLT) of extensively pretreated patients with solid tumors. Methods: Patients were considered for 90 Y-FAPI-46 therapy in case of (a) exhaustion of all approved therapies based on multidisciplinary tumor board decision and (b) high FAP expression, defined as SUVmax ≥ 10 in more than 50% of all lesions. If tolerated, posttherapeutic 90 Y-FAPI-46 bremsstrahlung scintigraphy was performed to visually confirm systemic distribution and focal tumor uptake, and 90 Y-FAPI-46 PET scans at multiple timepoints were performed to determine absorbed dose. Blood-based dosimetry was used to determine bone-marrow absorbed dose. Adverse Events were graded using CTCAE v.5.0. Results: Nine patients with either metastatic soft tissue or bone sarcoma (N = 6) and pancreatic cancer (N = 3) were treated between June 2020 and March 2021. Patients received a median of 3.8 (IQR 3.25-5.40) GBq for the first cycle and three patients received subsequent cycles with a median of 7.4 (IQR 7.3-7-5) GBq. Post-therapy 90 Y-FAPI-46 bremsstrahlung scintigraphy demonstrated sufficient 90 Y-FAPI-46 uptake in tumor lesions in 7 of 9 patients (78%). Mean absorbed dose was 0.52 Gy/GBq (IQR 0.41-0.65) in kidney, 0.04 Gy/GBq (IQR 0.03-0.06) in bone marrow and below 0.26 Gy/GBq in the lung and liver. Measured tumor lesions received up to 2.28 Gy/GBq (median 1.28Gy/GBq). Hematologic G3/G4 toxicities were noted in four patients (44%), of which

Our data give final proof that homing through the SDF-1/CXCR-4 axis is essential for the success of dual stem cell therapy.