Masters Thesis Defense - Use of Small Field Dosimeters to Develop a Treatment Delivery Unit QA for Stereotactic Radiation Therapy on the Helical TomoTherapy System

Who: Mary Ann Polityka

Time: 2pm, Thursday, 16th August, 2007

Place: P-250

Abstract: A treatment delivery unit quality assurance (QA) protocol for stereotactic body radiation therapy (SBRT) on the TomoTherapy Hi-Art system is developed in order to assess overall targeting accuracy and alignment of the linac, the jaws and the overhead laser. The Hexaphant^TM, an acrylic phantom designed for use with the BodyLoc stereotactic frame, is used to perform pin-prick tests in the sagittal and coronal planes with Gafchromic MD-55 film to determine the overall mechanical positioning error. A series of alignment tests is performed in order to determine if the radiation source is centered with respect to the jaws and binary collimator, to check the overhead (transverse) laser and to verify that the jaws are oriented such that the center of the radiation beam remains parallel to the plane of gantry rotation. Results show that the total displacement from the calculated radiation isocenter positioning to the measured radiation isocenter positioning was approximately 0.62 mm and that the TomoTherapy treatment unit is mechanically capable of delivering SBRT accurately using the BodyLoc stereotactic frame.

You can view other thesis abstracts here.