I am 73 and in the same boat as your dad. The 3T MRI is really accurate. I had a 7 mm lesion confined to the prostate, but my PSA was only 2.9. I had an MRI fusion biopsy which is where the doctor uses the MRI image with an ultrasound probe in your rectum to find the lesion when he takes the biopsy samples. I had a trans perineal biopsy under a local with no problems and would never have a transrectal due to two factors. One is the chance of infection from the rectum and the second is that the prostate is more assessable from the perineum.. He did a 30 core biopsy as I have a very large prostate and for mostly 3-4 Gleason but I had two cores with 4-3 Gleason which I why I elected for radiation, After the biopsy the doctors at Mayo Phoenix had me do a PSMA PET SCAN which showed that the cancer was confined to the prostate. My PSA had been in the 2.5 to 2.9 range for 5 years on my annual checkups and no one will venture a guess as to how long it was growing. I had my markers inserted last Friday along with Space Oar Gel to protect my rectum from the radiation. I hope this helps.