%0 Journal Article %A Gerardo dos Santos %A Rodriguez Monica %A Giglio Javier %A Savio Eduardo %A Omar Alonso %T Intraindividual Comparison of novel 18F-PSMA-1007 and Al18F-PSMA-HBED-CC PET/CT in the Prospective Evaluation of Prostate Cancer Patients with Biochemical Relapse: First experience in Uruguay. %D 2021 %J Journal of Nuclear Medicine %P 1326-1326 %V 62 %N supplement 1 %X 1326Objectives: Among several 18F-labeled prostate-specific-membrane-antigen (PSMA) targeted PET/CT tracers, the recently introduced 18F-PSMA-1007 had demonstrated interesting properties for the diagnostic evaluation of prostate cancer (PCa), as outstanding tumor uptake and minimal excretion through the urinary-tract. A novel radiotracer: [18F]AlF-PSMA-HBED-CC (18F-AlF-PSMA-11), was produced in our Centre, with suitable radiochemical purity for clinical purposes. The aim of this study was to prospectively compare the image quality and the diagnostic values of both tracers in a sample of PCa patients. Methods: A sample of 18 patients (median age: 69.5, range: 54-80 years; median PSA level: 1.2 ng/mL; range: 0.01-20.1 ng/mL; Gleason Score >9) with biochemical recurrence after radical prostatectomy (n=9, 50%) or radiotherapy were included between July-August 2020. Within 1-2 weeks they underwent a PET/CT scan with 18F-PSMA-1007 and with 18F-AlF-PSMA-11, randomly performed, with a 16 or 64-slice PET/CT with TOF correction, 120 or 60 minutes after the iv administration of 4.2 and 4.07 MBq/Kg, respectively. Normal- organ biodistribution and tumor uptake were examined using the maximum SUV (SUVm). Correlative imaging, histopathology and/or clinical follow-up were considered as reference standard (median follow-up time: 4.5 months, range: 4-5 months). Sensitivity and specificity were calculated. Results: The normal organ biodistribution of 18F-PSMA-1007 and Al18F-PSMA-11 has proven highly similar to other PSMA-targeted radiotracers, such as PSMA-617, DCFBC and DCFPyL. 18F-PSMA-1007 and Al18F-PSMA-HBED-11 PET/CT demonstrated abnormal findings in 15 and 13 patients (positivity rate: 83% and 72%), respectively. At least one suspicious lesion for prostate cancer metastasis was detected in 13 (72%) and 11 (61%) of 18 patients, for each tracer respectively. A total of 157 lesions were detected by at least one radiopharmaceutical in the following sites: bone (n=120), lymph-nodes (n=20), prostate (n=9), lung (n=7) and brain (n=1); adding a total of 142 for 18F-PSMA-1007 and 143 for 18F-AlF-PSMA-11. Discriminating by radiotracer in the total population, PET/CT with 18F-PSMA-1007 and 18F-AlF-PSMA-11 identified 105 and 115 bone lesions, 20 and 15 lymph node lesions, 9 and 6 prostate lesions, 7 and 6 lung lesions and 1 brain lesion both, respectively. For concordant lesions (n=127), we did not find a significantly different SUVm for both tracers: 14.8 (2.6-107.4) and 13.7 (2.5-75.3), median (range), for 18F-PSMA-1007 and Al18F-PSMA- 11, respectively (p=0.13). However, a significant correlation was found among both tracers’ SUVm (r = 0.94, n = 127, P< 0.00001). We found a significantly higher SUVm for Al18F-PSMA-11 in concordant bone lesions (n=100, P<0.0001) and for 18F-PSMA-1007 in lymph-node concordant lesions (n=14, P=0.011), while no significant differences were found in prostate and soft tissue lesions. Al18F-PSMA-11 had renal clearance and 18F-PSMA-1007 had hepatobiliary clearance. Uptake was significantly higher for Al18F-PSMA-11 than for 18F- PSMA-1007 in the kidneys (median SUVm, 46.2 vs. 25.9; p=0.0012) and urinary bladder (median SUVm, 71.2 vs. 5.1; p=0.0003), whereas 18F-PSMA-1007 showed significantly higher uptake in the liver (median SUV, 17.9 vs. 7.2; p=0.0003) and gallbladder (median SUVm, 22.8 vs. 2.2; p=0.0003). On a per patient basis the sensitivity and specificity values with their 95% C.I. were 0.93 (CI: 0.68 - 0.99) and 0.66 (95% CI: 0.09-0.99) for 18F-PSMA-1007; and 0.84 (CI: 0.54 - 0.98) and 0.60 (95% CI: 0.14-0.94) for Al18F-PSMA-HBED-11, respectively. Conclusions: 18F-PSMA-1007 and Al18F-PSMA- 11 PET/CT seem to be clinically equivalent imaging techniques and have relevant sensitivity for the detection of PCa lesions. Low urinary excretion of 18F-PSMA-1007 present clear advantage for pelvic interpretation. %U