Evaluating a discretized data acquisition method for couch modeling to streamline the commissioning process of radiological instruments

Background The commissioning of radiotherapy treatment planning system (RTPS) involves many time-consuming tests to maintain consistency between actual and planned dose. As the number of new technologies and peripheral devices increases year by year, there is a need for time-efficient and accurate commissioning of radiation therapy equipment. Couch modeling is one type of commissioning, and there are no recommended values for CT due to differences in equipment calibration between facilities. This study evaluated the optimal electron density (ED) for the couch using discretized gantry angles.
Results All discrete-angle groups showed a high correlation between the surface ED and dose difference between the actual and planned doses (|r|> 0.9). AcurosXB did not demonstrate a significant correlation between dose differences and each energy. For a small number of discretized gantry groups, the optimal couch modeling results revealed several combinations of surface and interior ED with the same score. Upon adding all couch thickness scores, all energy scores, and both algorithm scores, the optimal surface and interior EDs with the highest score across all couch thicknesses were 0.4 and 0.07, respectively.
Conclusions The optimal couch surface ED dose difference trend was identified, and the effectiveness indicated using the dose difference score from discrete-angle couch modeling. Using this method, couch modeling can be evaluated in a highly precise and quick manner, which helps in the commissioning of complicated linear accelerator and radiological treatment plans.