Intensity-modulated radiotherapy

Abstract

Intensity-modulated radiotherapy (IMRT) is a radiation delivery technique that allows dose sculpting to improve target coverage while sparing normal tissues. In an IMRT plan, the number of photons delivered (or fluence) varies within a field. Such variability can be used to avoid normal structures with lower radiation tolerance than the cancer and increases the ability to provide focal treatment. It does require significant quality assurance and consideration of patient setup and target motion to ensure treatment accuracy. While the technique itself is not more efficacious in achieving biochemical control, its ability to spare normal tissues allows for dose escalation, which does provide improved prostate cancer control. For prostate cancer, the cancer control benefit of dose escalation has driven a widespread adoption of IMRT for definitive external beam radiotherapy.