This guide provides a comprehensive overview of radiation therapy for prostate cancer in the United States. It explains the fundamental principles of how radiation targets cancer cells with precision while minimizing damage to healthy tissue. The article details the two primary pathways: External Beam Radiation (EBRT), including IMRT and SBRT, and Brachytherapy (internal radiation). Readers will learn about the entire treatment process, from the initial consultation and decision-making to managing side effects and recovery. Practical advice on navigating insurance, financial considerations, and the importance of second opinions is also included. Furthermore, the guide addresses the crucial, often overlooked topics of sexual health and long-term life after treatment. Ultimately, this resource aims to empower patients by demystifying the journey and replacing uncertainty with knowledge and confidence.