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

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

Blog Article

IntroductionDynamic 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.Materials and methodsFive 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 Me Christmas Sweater 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.ResultsThe 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% Mental Clarity for artery, 9.7% for tumor, 32.

7% for the bladder and 14.1% for the gluteal muscle.ConclusionDynamic 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.