Brachytherapy is a highly targeted form of radiation therapy used as a first-line treatment for favorable intermediate-risk prostate cancer. It involves placing tiny radioactive seeds directly into the prostate, allowing for a high, localized dose of radiation while minimizing exposure to nearby organs like the bladder and rectum. This internal radiation typically remains active over several weeks or months, gradually delivering treatment without the need for daily sessions like EBRT. Brachytherapy is most suitable for patients with smaller prostate glands, minimal urinary symptoms, and no history of significant obstructive voiding issues. It can be used alone or, in some cases, combined with external beam radiation or short-term androgen deprivation therapy for enhanced effect.