Evaluation of Tumor Control Based on Serial Multiparametric MRI and Post-Treatment Biopsies For Patients Treated With Dose Intensification to the Dominant Intra-Prostatic Lesion (DIL) Using Ultra-Hypofractionated, MR-Guided Radiotherapy

Patients will receive 9 Gy/fraction (45 Gy total) for five fractions to the DIL, while the remainder of the prostate will be treated to 30 Gy in 5 fractions.

A rectal spacer will be placed one week prior to simulation to achieve a separation of approximately 1 cm between the prostate and anterior rectal wall to further minimize rectal toxicity in these patients. The hydrogel will remain in the body for about 12 weeks.