An exploratory, feasibility and proof-of-concept study to evaluate the capability of a rectal probe scintigraphy device (ProxiScanTM) to detect PSMA specific radiopharmaceutical agent (ProstaScintÂ®; as a surrogate marker for prostate cancer) in patients who have undergone a radical prostatectomy for their disease, patients with multiple negative prostate biopsies and patients with known primary prostate cancer. Developed by Hybridyne Imaging Technologies, Inc. ProxiScanTM is a small cadmium zinc telluride (CST)-based compact gamma camera. It is the same size as a trans-rectal ultrasound (TRUS), currently used for prostate biopsy guidance. Men with multiple positive biopsies will be considered controls. Prostate cancer sextant biopsy histology results will be correlated with ProxiScanTM, TRUS, MRI and SPECT/CT. The investigators hypothesize that it will be safe and feasible to utilize a rectal probe scintigraphy (ProxiScanTM) to detect PSMA specific ProstaScintÂ®, thus identifying and localizing the tumour sites within the prostate and surrounding areas.