68 Gallium-Prostate Specific Membrane Antigen ( 68 Ga-PSMA) is an emerging radioactive positron emission tomography (PET) tracer that shows high affinity for cell surface transmembrane protein antigen that is over-expressed in most prostate cancer cells [1], leading to promising results in the diagnostic work-up of prostate cancer patients [2]. This modality was introduced in biochemically recurrent cancer prostate patients as other imaging modalities showed low detection rates specially in...

This is a retrospective study done on 120 cancer prostate patients presenting with biochemical recurrence post local therapy. Median prostate-specific antigen (PSA) level was 2.2 ng/mL (range 0.2–81 ng/mL). Head to mid thigh PET/CT exams were done after 60 minutes from injection of 140-160 Mbq of 68 Ga-PSMA tracer. The CT component was of high diagnostic quality. Exam interpretation was done by 2double trained radiology and nuclear medicine physicians specialised in PET/CTreporting. The...

The detection rates were correlated with the PSA level, which showed positive detection rate at PSA <1.0ng/ml reaching 55%, at PSA between 1.0-2.0 ng/ml reaching 93% and up to 98% at PSA level >2.0 ng/ml. 68 Ga-PSMA PET (compared to CT) exclusively detected the site of recurrence in 30% of the patients, and detected additional involved regions in 23% of the patients. The additional positive lesions were of normal sized lymph node metastases, small local recurrent masses, or early bone...

68 Ga-PSMA PET/CT proved its high diagnostic sensitivity in detecting the site of recurrence in patients with biochemical recurrence even at low PSA levels. This explains the recommendation of European association of urology to use Ga-PSMA PET/CT in biochemically recurrent patients leading to earlier detection of site of recurrence and accordingly initiate the proper management plan.

Yehia Omar, MD PET/CT unit, Misr Radiology Center, Cairo,Egypt. Omar.y@misrradiologycenter.com. Moustafa Abdel Kawi,MD Lecturer of Radiodiagnosis, Helwan University, Cairo,Egypt. moustafa.kawi@gmail.com

1-Banerjee SR, Pullambhatla M, Byun Y, Nimmagadda S, Green G, Fox JJ, et al. 68Ga-labeled inhibitors of prostate-specific membrane antigen (PSMA) for imaging prostate cancer. J Med Chem. 2010;53(14):5333–41. 2-Afshar-Oromieh A, Malcher A, Eder M, Eisenhut M, Linhart HG, Hadaschik BA, et al. PET imaging with a [68Ga] gallium-labelled PSMA ligand for the diagnosis of prostate cancer: biodistribution in humans and first evaluation of tumour lesions. Eur J NuclMed Mol Imaging. 2013;40(4):486–95....