Patient-specific tumor and respiratory monitoring phantom design for quality controls of stereotactic ablative body radiotherapy in lung cancer cases

The design, production and adaptability to clinical routine of a patient-specific tumor and respiratory monitoring phantom (TRMP) was investigated using 3D printer technology. TRMP and GTV modelling were done using 4D-CT images of the inhalation phase. The model was converted to STL (Stereolithography) format and printed with STH (Strong Herbal) biopolymer with HU (Hounsfield Unit) suitable for imaging purposes. The assembly of TRMP motorized parts and mechanical equipment has been completed and made suitable for clinical use. In the first part of the study, the deviations of radio-opaque markers attached to the TRMP sternum to perform mechanical quality control tests and T1-7 costal vertebrae in CC, AP, and LAT directions were evaluated. In the second part of the study, in order to evaluate the usability of the TRMP in quality assurance (QA), point dose measurements with BeO OSL dosimetry and EBT3 gafchromic film measurements were taken in Trilogy® radiotherapy accelerator and CyberKnife® robotic radiosurgery accelerator. In this study, we present a highly flexible TMRP capable of performing independent internal and external motions. TRMP was successfully tested in different treatment accelerators, both mechanically and dosimetrically.