Seminar

Medical Physics Seminar – Monday, February 14, 2011

MRI-Guided, Adaptive Brachytherapy (BT): Rationales for Intensity-Modulated BT (IMBT)

Yusung Kim, Ph.D. (guest of Dr. Wolfgang Tome)
Assistant Professor, Department of Radiation Oncology, University of Iowa Hospitals & Clinics, Iowa City, IOWA

A patterns-of-care study confirmed brachytherapy (BT) remains the cornerstone of radiotherapy for cervical cancer. Utilizing magnetic resonance imaging (MRI) for BT is currently gaining momentum, since it allows adaptation to macroscopic tumor volume and regression. We investigated tumor coverage and organs-at-risk (OAR) sparing of Manchester system based high dose rate (HDR) for different high risk (HR)-CTV volumes per GET-ESTRO guidelines. In addition, we quantify the impact of volume optimization (i.e. adaptive planning), when utilizing tandem and ovoid (T&O) applicators in high resolution (3.0 Tesla) MRI for different HR-CTV sizes. Using 25 HDR plans of six patients with FIGO stage Ib1-IV cervical cancer, a new plan was generated based on MRI, utilizing titanium Fletcher-Suit-Delclos-style T&O applicators. Therefore, for three different tumor size subgroups, the tumor coverage (e.g. D90 of HR-CTV) and normal tissue sparing (e.g. D2cc of OAR) were compared. In addition, it was estimated how much tumor coverage and normal tissue sparing could be improved when MRI-guided, adaptive planning technique. Based upon the findings, the approach of intensity-modulated BT (IMBT) that has been studied in UI is introduced.

Location: 1325 (HSLC) Health Sciences Learning Center, 750 Highland Avenue, Madison, WI

Time: 4:00pm-5:00pm