How to Perform FAPI PET? An Expedited Systematic Review Providing a Recommendation for FAPI PET Imaging With Different FAPI Tracers.

This expedited systematic review aims to provide the first overview of the different Fibroblast activation protein inhibitor (FAPI) PET scan procedures in the literature and discuss how to efficiently obtain optimal FAPI PET images based on the best available evidence. The PubMed, Embase, Cochrane Library, and Web of Science databases were systematically searched in April 2023. Peer-reviewed cohort studies published in English and used FAPI tracers were included. Articles were excluded if critical scan procedure information was missing, or the article was not retrievable from a university library within 30 days. Data were grouped according to the FAPI tracer applied. Meta-analysis with proper statistics was deemed not feasible based on a pilot study. A total of 946 records were identified. After screening, 159 studies were included. [68Ga]Ga-FAPI-04 was applied in 98 studies (61%), followed by [68Ga]Ga-FAPI-46 in 19 studies (12%). Most studies did not report specific patient preparation. A mean/median administered activity of 80-200 MBq was most common; however, wide ranges were seen in [68Ga]Ga-FAPI-04 PET studies (56-370 MBq). An injection-to-scan-time of 60 minutes was dominant for all FAPI PET studies. A possible trend toward shorter injection-to-scan times was observed for [68Ga]Ga-FAPI-46. Three studies evaluated [68Ga]Ga-FAPI-46 PET acquisition at multiple time points in more than 593 cancer lesions, all yielding equivalent tumor detection at 10 minutes vs later time points despite slightly lower tumor-to-background Ratios. Despite the wide ranges, most institutions administer an average of 80-200 MBq [68Ga]Ga-FAPI-04/46 and scan patients at 60 minutes postinjection. For [68Ga]Ga-FAPI-46, the present evidence consistently supports the feasibility of image acquisition earlier than 30 minutes. Currently, data on the optimal FAPI PET scan procedure are limited, and more studies are encouraged. The current review can serve as a temporary guideline for institutions planning FAPI PET studies.

The clinical consequences of routine 68Ga-PSMA-11 PET/CT in patients with newly diagnosed prostate cancer, ISUP grade 5 and no metastases based on standard imaging - preliminary results.

AIM: To evaluate the clinical consequences of prostate specific membrane antigen (PSMA) PET/CT for primary staging in patients with ISUP grade 5 (Gleason score ≥9) prostate cancer (PCa), and no definitive distant metastases based on standard imaging. METHODS: At our tertial referral center, PSMA PET/CT became standard of care from August 2018 for primary staging of prostate cancer given the following criteria: (1) no prior treatment for prostate cancer, (2) ISUP grade 5, (3) no definitive metastases on standard imaging (contrast enhanced CT and bone scintigraphy), and (4) deemed suitable for treatment with curative intent based on comorbidity and life expectancy. We present the preliminary results of first six months recruitment with 12 months of follow-up. RESULTS: Forty-eight patients (mean age 69 years, median PSA 13.0 ng/mL, 20 patients with locally advanced PCa) were included. CT was positive in pelvic lymph nodes in two patients, bone scintigraphy was equivocal in three patients. PSMA PET/CT showed pathological uptake outside the prostatic bed in 22 patients (46%) of which 13 patients (27%) showed lesions confined to regional lymph nodes, and nine patients (19%) showed nonregional lymph node metastases and/or bone metastases. PSMA PET/CT changed the treatment strategy from curatively intended treatment to palliative treatment in 18 patients (38%). CONCLUSION: PMSA PET/CT revealed pathological uptake in a large proportion of high-risk patients at primary staging among patients with no definite metastases on standard imaging leading to change of patient management in 38% of the patients.

The value of 68 Ga-PSMA-11 PET/CT in patients with prostate cancer and inconclusive standard imaging at primary staging.

OBJECTIVE: The current standard imaging recommended for primary staging of intermediate- and high-risk prostate cancer (PCa) consists of bone scintigraphy (BS) and computed tomography (CT). Some patients will have equivocal lesions or divergent findings on BS and CT, leading to inconclusive disease staging. Our aim was to investigate the value of 68 Ga-PSMA-11 PET/CT in PCa with inconclusive disease stage based on standard imaging. METHODS: We made a single-center study of patients with newly diagnosed PCa who underwent a 68 Ga-PSMA-11 PET/CT due to equivocal findings or discrepancies between BS and CT from 1 January 2017 to 31 December 2020. The value of 68 Ga-PSMA-11 PET/CT was evaluated for each location of equivocal findings (regional lymphnode, nonregional lymphnodes, bones and other metastases) and on a patient level. RESULTS: Seventy-six patients were included in the study (62 patients with 72 equivocal lesions, 14 with discrepancy between BS and CT). Equivocal lesions were predominately in the bones (61%, 44/72), or in the regional lymph nodes (17%, 12/72). 68 Ga-PSMA-11 PET/CT provided a conclusive diagnosis in 90% (65/72) of the equivocal lesions. All patients with discrepancies between BS and CT had definite answers after 68 Ga-PSMA-11 PET/CT. 68 Ga-PSMA-11 PET/CT also uncovered 32 additional sites of metastasis in 25 patients not visible by standard imaging. CONCLUSION: 68 Ga-PSMA-11 PET/CT provides a definite disease stage in more than 90% of newly diagnosed patients with inconclusive standard imaging. Furthermore, it revealed additional sites of metastasis in 25 patients not detected by standard imaging.