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Introduction: [ 18 F]PSMA-1007 has potential advantages over [ 68  Ga]Ga-PSMA-11, although limited prospective data evaluating diagnostic performance exist. The aims of this study are to describe the concordance of [ 18 FPSMA-1007 and [ 68  Ga]Ga-PSMA-11 for TNM with the American Joint Committee on Cancer (AJCC) prognostic stage and assess differences in tracer uptake., Methods: Fifty men (mean age 71.8) were imaged with [ 68  Ga]Ga-PSMA-11 and [ 18 F]PSMA-1007 < 4 weeks apart. Images were independently reported according to TNM by two experienced nuclear medicine specialists blinded to the other scan and prior imaging. Discordant results were resolved by a third independent nuclear medicine specialist. Quantitative analysis of lesion uptake and physiologic tissue for each tracer was performed by one experienced reader., Results: Scan indications were initial staging (n = 12), biochemical recurrence (n = 27) and metastatic disease evaluation (n = 11). Most patients had ISUP grade group 3 or higher. Median PSA value was 2.7 ng/ml (IQR 0.7-12.0), and a minority of patients (28%) were currently treated with androgen deprivation therapy. [ 18 F]PSMA-1007 uptake was significantly higher than [ 68 Ga]Ga-PSMA-11 in local recurrence, nodal and distant metastases and most physiologic sites (including bone) except for urinary bladder which was significantly lower. [ 18 F]PSMA-1007 upstaged local prostate staging in 5/17 patients, local recurrence in 3/33 patients, regional nodal disease in 3/50 patients and 1 distant metastasis (bladder). [ 68 Ga]Ga-PSMA-11 upstaged regional nodal disease in 1/50 patients and distant metastasis in one patient (right adrenal). Overall AJCC prognostic stage was concordant in 46/50 (92%) patients, with two patients upstaged for both [ 18 F]PSMA-1007 and [ 68 Ga]Ga-PSMA-11. [ 18 F]PSMA-1007 had more equivocal results (one regional node; six equivocal bone lesions, one of which was subsequently confirmed metastatic) than [ 68 Ga]Ga-PSMA-11 (one equivocal local recurrence)., Conclusion: Overall AJCC prognostic stage was similar (92%) between [ 18 F]PSMA-1007 and [ 68 Ga]Ga-PSMA-11. [ 18 F]PSMA-1007 demonstrates higher uptake within involved nodes and distant metastases and most physiologic sites except urinary bladder which aided [ 18 F]PSMA-1007 local staging of the prostate primary/local recurrence and regional nodal disease adjacent ureters. However, [ 18 F]PSMA-1007 liver uptake obscured a solitary right adrenal metastasis, and more equivocal bone lesions were identified. Trial registration The study was registered with Australia New Zealand Clinical Trials Registry (ACTRN12618000665235) on 24 April 2018., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: [ 18 F]PSMA-1007 offers advantages of low urinary tracer excretion and theoretical improved spatial resolution for imaging prostate cancer. However, non-specific bone lesions (NSBLs), defined as mild to moderate focal bone uptake without a typical morphological correlate on CT, are a common finding on [ 18 F]PSMA-1007 PET/CT. The purpose of this study was to investigate the clinical outcomes of patients with [ 18 F]PSMA-1007 avid NSBLs, to determine whether patients with NSBLs represent a higher risk clinical cohort, and to determine whether SUVmax can be used as a classifier of bone metastasis., Methods: A retrospective audit of 214 men with prostate cancer was performed to investigate the clinical outcomes of [ 18 F]PSMA-1007 avid NSBLs according to defined criteria. We also compared the serum PSA, Gleason score, and uptake time of patients with [ 18 F]PSMA-1007 avid NSBLs to patients without [ 18 F]PSMA-1007 avid bone lesions. Finally, we analysed an SUVmax threshold to identify bone metastases using ROC curve analysis., Results: Ninety-four of 214 patients (43.9%) demonstrated at least one NSBL. No [ 18 F]PSMA-1007 avid NSBLs met criteria for a likely malignant or definitely malignant lesion after a median 15.8-month follow-up interval (11.9% definitely benign, 50.3% likely benign, and 37.7% equivocal). There were no statistically significant differences in serum PSA, Gleason score, and uptake time between patients with [ 18 F]PSMA-1007 avid NSBLs and those without [ 18 F]PSMA-1007 avid bone lesions. All NSBLs with adequate follow-up had SUVmax ≤ 11.1. The value of the highest SUVmax distinguished between NSBLs and definite prostate cancer bone metastases, whereby an SUVmax threshold of ≥ 7.2 maximized the Youden's index., Conclusion: [ 18 F]PSMA-1007 avid NSBLs rarely represent prostate cancer bone metastases. When identified in the absence of definite metastatic disease elsewhere, it is appropriate to classify those with SUVmax < 7.2 as likely benign. NSBLs with SUVmax 7.2-11.1 may be classified as equivocal or metastatic, with patient clinical risk factors, scan appearance, and potential management implications used to guide interpretation., (© 2021. Crown.)