Dual-phase 68Ga-PSMA-11 PET/CT may increase the rate of detected lesions in prostate cancer patients.

Abstract

BACKGROUND\nThis study was conducted to compare the early static (3-6\u2009min post-injection (p.i.)) and standard whole body (1\u2009h, p.i.) 68Ga-PSMA-11 PET/CT imaging for detection of lesions in prostate cancer (PC) patients.\n\n\nMATERIALS AND METHODS\nIn this study, PC patients suspected of recurrence underwent 68Ga-PSMA-11 PET/CT. Early static images were acquired from the pelvis and the lower abdomen 3-5 minutes after radiotracer injection and, a routine whole body scan was performed from the skull to the mid-thigh 1\u2009h after injection. Quantitative analysis (SUVmax) was evaluated in suspicious lesions.\n\n\nRESULTS\nOf 19 evaluated PC patients with a median age of 72\u2009±\u20091.66 years (range: 55-85 years) and prostate-specific antigen (PSA) of 1.72\u2009±\u20096.11\u2009ng/ml (range: 0.1-100\u2009ng/ml) (median\u2009±\u2009SE), 16 showed positive in the whole body PET/CT. All of the patients with positive whole body scans due to pelvic involvement had positive early scan results. Totally, 22 lesions were detected in both early and delay scans in the pelvic which 16 were related to prostate involvement, 4 were related to lymph node involvement, and 2 were related to bone involvement. Moreover, in addition to the mentioned 22 lesions, early PET imaging successfully detected local recurrence in a patient who was negative on WB PET/ CT; this lesion was masked in the delay scan due to bladder activity. The median SUVmax values of the early and delay scans were 3.69\u2009±\u20091.07 (median\u2009±\u2009SE) (range: 1.2-14.5) and 5.85\u2009±\u20091.69 (range: 3.1-23.4), respectively. (p\u2009=\u20090.005).\n\n\nCONCLUSION\nEarly static 68Ga-PSMA-11 PET/CT imaging might discriminate metastases from urinary bladder activity. Therefore, early static imaging in combination with whole body 60-min p.i. imaging can improve the detection of local involvement pelvic disease.