Multileaf collimators (MLC) have become essential tools to help provide highly conformal radiation fields for cancer treatment. Ideally, the LMC leaves are positioned under computer control to predetermined positions to a tolerance of 0.1mm. However, it is up to the user to establish the accuracy of the leaf positioning system and to provide regular quality assurance of its precision. In order for this to be time efficient, it is desirable for the prices leaf edge positions to be determined automatically using radiographic film images of the MLC shaped field. The purpose of this work is to investigate the relationship between the film image of the MLC leaf and its actual position by mathematically modeling the shape of the image penumbra.

This study was funded by Simons Grant 265210 and NSF 20822-1015912.