Active tracking and dynamic dose delivery for robotic couch in radiation therapy

Precise and accurate dose delivery is critically important in external beam radiation therapy. In many cases target-volumes are stationary, but the problem arises when the tumors move significantly due to cardiac and respiratory motions. This is a case for tumors in lung, esophagus, pancreas, liver, prostate, breast, and other organs in thoracic and abdominal regions. In the article we have described the Active Tracking and Dynamic Dose Delivery (ATDD) technique for real-time tumor motion compensation. In this approach, the robotic treatment table moves while delivering the radiation beam and compensates for breathing-induced tumor motion. Many parameters of the control system, such as patient mass or breathing pattern, are initially uncertain and may vary during the treatment. To solve these problems, feedforward adaptive control was adopted to minimize irradiation to healthy tissue and spare critical organs while ensuring prescribed radiation dose coverage to the target-volume.