Radiation therapy (RT) is essential to many cancer treatments. Traditionally, RT is designed per patient on a CT scan acquired before beginning treatment; then, for each day of treatment, the patient’s body and internal anatomy must match the prior CT for the most effective therapy. Recent technology advances make it possible to acquire a new CT and design a new radiation plan in minutes, allowing adjustment for changes in the anatomy. This is called online adaptive RT and requires specialized software.
A new photon linear accelerator system with online adaptive software was installed, tested, and commissioned at MGH. Online adaptive RT was offered for patients with bladder cancer.
Online adaptive RT made it possible to adjust the radiation plan for daily changes in bladder filling and position, ensuring that the radiation reached the tumor while sparing the adjacent small bowel. Due to the added precision of online adaptive RT, margins around the cancer were reduced from 8mm to 5mm, reducing the radiation dose to healthy tissue even further.
Online adaptive RT reduced radiation dose to healthy tissue when treating bladder cancer with radiation. Online adaptive RT will be offered for more patients, including additional disease sites.