RecruitingPhase 3Radiation therapyVascular Optimized Radiotherapy Tuned to Critical Structures for Erectile Function Using High-Precision X-Ray TreatmentWith people living longer after being treated for prostate cancer, quality of life has become a concern when considering the treatment plan. Sometimes after radiation therapy, patients may experience problems that affect the urinary and bowel systems, along with sexual function. Stereotactic body radiotherapy (SBRT) is a type of radiation technique that delivers five high doses of radiation. At University of California at Los Angeles (UCLA), we have the option to administer SBRT in both our CT-guided and MRI-guided radiation machines. This trial aims to determine the most effective method for protecting the nerves and blood vessels essential for erectile function, utilizing a technique known as neurovascular sparing. This technique uses images (i.e., MRI) to map the neurovascular bundles of nerves and blood vessels, which are crucial for erectile function. "Adapting" the radiotherapy treatment for each of these five treatment sessions could enable a more precise delivery of your radiation treatment that is customized based on your internal anatomy immediately before the treatment starts. This is also a standard and low-risk intervention used in many different types of cancer. However, it is a very labor-intensive and time-consuming procedure that requires a team of experts to work together before each of your radiotherapy sessions. We are unsure if the increased complexity associated with this adaptive treatment reduces side effects.