Transmission Dose Estimation Algorithm for Irregularly Shaped Radiation Field

Measurement of transmission dose is useful for in vivo dosimetry. In this study, the algorithm for estimating the transmission dose for open radiation fields was modified for application to partially blocked radiation fields. The beam data was measured with a flat solid phantom with various blocked fields. A new correction algorithm for partially blocked radiation field was developed from the measured data. This algorithm was tested in some settings simulating clinical treatment with an irregular field shape. The correction algorithm for the beam block could accurately reflect the effect of the beam block, with an error within ± 1.0%, with both square fields and irregularly shaped fields. This algorithm can accurately estimate the transmission dose in most radiation treatment settings, including irregularly shaped fiel