Early differences in dynamic uptake of 68Ga-PSMA-11 in primary prostate cancer: A test-retest study

• Published in: PloS one Vol. 16; no. 2; p. e0246394
• Main Authors: Olde Heuvel, J, de Wit-van der Veen, B J, Sinaasappel, M, Slump, C H, Stokkel, M P M
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 2021; Public Library of Science (PLoS)
• Subjects: Aged; Antigens; Biology and Life Sciences; Biopsy; Bladder; Computed tomography; Current distribution; Data analysis; Diagnostic systems; Drafting software; Drug dosages; Editing; Gallium Isotopes - administration & dosage; Gallium Isotopes - analysis; Gallium Isotopes - pharmacokinetics; Gallium Radioisotopes - administration & dosage; Gallium Radioisotopes - analysis; Gallium Radioisotopes - pharmacokinetics; Health care facilities; Humans; Male; Mechatronics; Medical imaging; Medicine; Medicine and Health Sciences; Methodology; Nuclear medicine; Patients; Pelvis - pathology; Positron emission; Positron Emission Tomography Computed Tomography; Prostate - diagnostic imaging; Prostate - pathology; Prostate cancer; Prostatic Neoplasms - diagnostic imaging; Prostatic Neoplasms - pathology; Research and Analysis Methods; Robotics; Tomography; Tumor Burden; Visual aspects; Visualization; Netherlands
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0246394

Dynamic PET/CT allows visualization of pharmacokinetics over the time, in contrast to static whole body PET/CT. The objective of this study was to assess 68Ga-PSMA-11 uptake in pathological lesions and benign tissue, within 30 minutes after injection in primary prostate cancer (PCa) patients in test-retest setting.
Five patients, with biopsy proven PCa, were scanned dynamically in list mode for 30 minutes on a digital PET/CT-scanner directly after an intravenous bolus injection of 100 MBq 68Ga-PSMA-11. Approximately 45 minutes after injection a static whole body scan was acquired, followed by a one bed position scan of the pelvic region. The scans were repeated approximately four weeks later, without any intervention in between. Semi-quantitative assessment was performed using regions-of-interest in the prostate tumor, bladder, gluteal muscle and iliac artery. Time-activity curves were extracted from the counts in these regions and the intra-patient variability between both scans was assessed.
The uptake of the iliac artery and gluteal muscle reached a plateau after 5 and 3 minutes, respectively. The population fell apart in two groups with respect to tumor uptake: in some patients the tumor uptake reached a plateau after 5 minutes, whereas in other patients the uptake kept increasing, which correlated with larger tumor volumes on PET/CT scan. Median intra-patient variation between both scans was 12.2% for artery, 9.7% for tumor, 32.7% for the bladder and 14.1% for the gluteal muscle.
Dynamic 68Ga-PSMA-11 PET/CT scans, with a time interval of four weeks, are reproducible with a 10% variation in uptake in the primary prostate tumor. An uptake plateau was reached for the iliac artery and gluteal muscle within 5 minutes post-injection. A larger tumor volume seems to be related to continued tumor uptake. This information might be relevant for both response monitoring and PSMA-based radionuclide therapies.