How does external beam radiation therapy work for prostate cancer treatment?
In external beam radiation therapy, X-rays are generated by a machine and focused on the prostate. Treatment usually takes place daily for several weeks, for a total of 40–45 treatment sessions. Over the past 5 to 10 years, the computer software controlling the beam delivery has advanced, allowing more precise focusing of the radiation beam and less damage to surrounding structures. The better precision of the beam results in fewer radiation-induced side effects. The primary external radiation therapy technique used at NYU is a daily intensity-modulated radiation therapy with image guidance via cone-beam CT scan (IMRT/IGRT). In intensity-modulated radiation therapy (IMRT), radiation is delivered from many different angles by a machine rotating around the patient. The intensity of the radiation is altered depending on its path, helping to minimize damage to surrounding healthy tissues. In image-guided radiation therapy (IGRT), each daily radiation treatment session is preceded by a CT s
