IGRT (Image-Guided Radiation Therapy)

In the past, radiation was delivered by looking at marks drawn on the skin with a marker or films taken months ago. However, even having gas in the bowel can instantly shift the position of a prostate or bladder tumor by centimeters. IGRT takes an up-to-date photo that very second before delivering radiation to the patient, and if the tumor has moved, it shifts the robotic bed, refocusing the beam back on the tumor.

Thanks to IGRT, the target is not missed, and the beams hit the tumor 100%. With this confidence, doctors narrow the safety margin (wide area) they give around the tumor out of fear of "accidentally missing". Thus, the healthy bowel, heart, or spinal cord right next to the tumor does not receive radiation, and side effects drop dramatically.