Fall 2005 Seminar Series

DATE: Thursday, October 6, 2005
LOCATION: E40-298
TIME: 4:15pm
Reception immediately following in the Philip M. Morse Reading Room, E40-106

SPEAKER:
Dr. Thomas Bortfeld
Director of Physics Research in Radiation Oncology
Massachusetts General Hospital

TITLE
Operations Research Meets Radiation Oncology

ABSTRACT
In intensity-modulated radiation therapy (IMRT) the intensities of many small radiation “beamlets” are individually adjusted to shape the spatial radiation dose distribution to the tumor target volume while sparing surrounding healthy tissues and “organs at risk”. The first IMRT patient was treated 10 years ago. Today IMRT is successfully applied in clinical practice at most radiation oncology departments in the USA and it has in fact become the standard treatment of many cancers, such as prostate cancer. The key component of IMRT is the treatment planning software that optimizes the intensities of the 1,000 - 10,000 beamlets. In this lecture we will review the “standard model” of IMRT optimization, including the sub-problem to decompose intensity maps into shapes of beam segments (apertures). We will then discuss new challenges in IMRT optimization, in particular multi-objective optimization strategies, and the integration of organ motion into the optimization approaches. Finally, we will give a brief overview of the non-convex optimization problems of beam angle placement, direct aperture optimization, and the inclusion of dose-volume constraints. Operations Research has the potential to have a major impact in all of these areas and can lead to a real benefit for the patients.