[Development of Novel Immobilization Adapter for Head and Neck Radiotherapy with Low-attenuation Material].

Purpose: The dosimetric error due to immobilization devices has been highlighted by the AAPM Task Group 176. We developed a novel low-radiation-absorbent immobilization adaptor (HMA), which can be used with a Styrofoam headrest for head and neck region in radiotherapy. The purpose of this study was to investigate the impact of the HMA on the dose distribution and compare with a commercially released plastic adapter.

Development of a novel low-radiation-absorbent lok-bar to reduce X-ray scattering and absorption in RapidArc treatment planning and dose delivery.

We developed a novel low-radiation-absorbent lok-bar (HM-bar) that is used to secure the immobilizers to the couch. The aim of this study was to investigate the X-ray scattering and absorption properties of the HM-bar in computed tomography (CT) simulation and radiotherapy dose delivery using the Varian Exact™ lok-bar (VL-bar) as a benchmark. CT images were obtained with or without lok-bar, and then each image was visually evaluated for artifacts.