| Summary: | 碩士 === 國立陽明大學 === 醫學工程研究所 === 93 === Aim: Homogeneous head phantom was designed for the verification of three-dimensional(3D) absorbed dose distribution in intensity-modulated radiotherapy(IMRT). Based on a computed tomography scan of the phantom, an intensity-modulated radiotherapy plan for a nasopharynx carcinoma was calculated using an inverse planning system (CadPlan, Varian Medical Systems, U, S,A).
Materials and Methods: The plan consisted seven beams delivered in a step and shoot technique out of 163 sub-fields. Immediately before and after irradiation 3D magnetic resonance (MR) imaging of the phantom were performed using a Spin-echo and 3D-Fast spin pulse sequence for induced image intensity change in the gel’s magnetic resonance images.
Results and Discussion: Measurement and planning show good agreement in regions of standard Fricke gel with an average deviation below 5%. In these areas also expend sensitivity of the dose response and multi-shape were observed as compared to standard Fricke gel. This MRI-based Fricke dosimeter gel has proven to be a useful and valuable pre-clinical tool for evaluating complex treatment planning delivery systems and procedures.
|
|---|
