TITLE:  Radiation therapy treatment planning with continuous dose
delivery for head-and-neck tumours

SPEAKER: Kimia Ghobadi

ABSTRACT:

In this talk we explore automated inverse treatment planning for Gamma Knife Perfexion to treat head-and-neck tumours. The main goal in designing a treatment plan is to deliver an appropriate amount of dose to tumour structures while avoiding the surrounding healthy tissue as much as possible. In continuous dose delivery treatment planning, the radiation is delivered with a continuous beam along a path inside the tumour instead of the conventional method of using multiple discrete beams.

To obtain a quality treatment plan, we first use a set of approximation algorithms to find the position of the focal points of the shots inside the tumour volume. We then used these focal points to construct a path that covers the tumour volume. Once the path is selected, a
mixed-integer optimization model and its approximated linear model are formulated to find the beam intensity and duration for each point on the path. In this optimization model we minimize the dose spillage to healthy organs while ensuring the tumour receives the prescribed dose.
We impose additional clinical and machine constraints such as maximum dose to healthy organs, maximizing the utility of the available beams, speed constraints for the radiation unit, etc. We test our plan on clinical test cases and observe that the quality of the plans are better
or comparable with clinical treatment planning.