Safety and Efficacy of 21 Gy, 23 Gy and 25 Gy for High Dose Rate (HDR) Prostate Brachytherapy

This trial is testing three different radiation doses for a high-dose-rate brachytherapy procedure (where a radiation source is placed temporarily inside the prostate) to find the safest and most effective single dose for men with early-stage prostate cancer. **You may be eligible if...** - You have been diagnosed with early-stage prostate cancer confirmed by biopsy or cell testing - Your cancer is classified as low-risk (small tumor, low Gleason score, and PSA under 10) or favorable intermediate-risk (slightly higher Gleason score but limited spread) - You may have received hormone therapy prior to this treatment **You may NOT be eligible if...** - Your cancer has spread to lymph nodes or other organs - You have had prior radiation to the pelvic area - You have very large prostate gland size that would make the procedure technically difficult - You have serious urinary blockage problems Talk to your doctor to see if this trial is right for you.