Seminar : Adaptive and Robust Radiation Therapy

Speaker:

Timothy C. Y. Chan

Assistant Professor

Mechanical & Industrial Engineering

University of Toronto

Date, Time, Location:

Monday, October 17, 2011

3:00pm - 4:00pm

Mohler Laboratory, Room 451

Title:

ARRT: Adaptive and Robust Radiation Therapy

Abstract:

The traditional approach to robust intensity-modulated radiation therapy treatment planning involves creating an appropriate uncertainty set to model the uncertain effect, solving a single treatment planning problem, and then delivering the same treatment over multiple weeks. In this talk, I will present an adaptive robust optimization approach to IMRT optimization, where information gathered in previous treatment sessions is used to update a model of uncertainty and guide treatment plan re-optimization for the next session. Such an approach allows for the estimate of the uncertain effect to improve as the treatment progresses. This approach involves solving a sequence of linear programs, and is therefore highly tractable. I will present computational results for a lung cancer case where the dominant uncertainty is in the patient’s breathing motion. Using this adaptive robust method, I demonstrate that it is possible to attain significant and simultaneous improvement in both tumor coverage and organ sparing over the non-adaptive approach. I also show that it is possible to closely approximate “prescient” solutions, and provide some theoretical insight as to why this occurs.

Biography:

Timothy C. Y. Chan is an Assistant Professor in the department of Mechanical and Industrial Engineering at the University of Toronto.  His primary research interests are in optimization under uncertainty and the application of optimization methods to radiation therapy, health care operations and sustainability.  He received his B.Sc. in Applied Mathematics from the University of British Columbia, and his Ph.D. in Operations Research from the Massachusetts Institute of Technology.  Before coming to Toronto, he was an Associate in the Chicago office of McKinsey and Company, a global management consulting firm.  During that time, he advised leading companies in the fields of medical device technology, travel and hospitality, telecommunications, and energy on issues of strategy, organization, technology and operations.