Date of Graduation

8-2010

Document Type

Thesis (MS)

Program Affiliation

Medical Physics

Degree Name

Masters of Science (MS)

Advisor/Committee Chair

Mohammad Salehpour

Committee Member

Firas Mourtada

Committee Member

Sean Zhang

Committee Member

Gloria Beyer

Committee Member

R. Allen White

Abstract

In external beam radiation therapy, it is imperative that the prescribed dose is administered to the correct location and in the correct amount. Though several ex vivo methods of quality assurance are currently employed to achieve this goal, verifying that the correct dose is received within the patient in situ is impossible without the capability of measuring dose inside the patient. Recently, a method of measuring dose delivered within the patient has been developed, an implantable MOSFET dosimeter. This dosimeter is implanted within the patient and records the dose received. Since the dosimeter is implanted in the patient, it could serve a dual function as a fiducial marker for image guided radiation therapy (IGRT) treatment if it could be modified to be visible on x-rays. In this study, modifications to the MOSFET dosimeter were made to increase its visibility for IGRT treatment. To test whether the modifications hindered the dosimeter’s ability to accurately measure and transmit dose information, the energy dependence, angular dependence and wireless read range of the modified dosimeter were measured and compared to unmodified dosimeters. It was found that the modified dosimeter performed as well as the unmodified dosimeter while also being suitable for use as a fiducial marker for IGRT treatment.

Keywords

fiducial marker, image guided radiation therapy, quality assurance, MOSFET dosimetry, in situ dosimetry, in vivo dosimetry