Development of geometric uncertainty assessment system for precise radiotherapy

Abstract

During the radiotherapy, the precise delivery of a planned beam may be hindered by geometrical uncertainties of machine related errors and patient related errors. Those geometrical uncertainties can make the treatment beam miss the target volume and accidentally hit the healthy organs. Hence, consequently, the target volume receive less dose than therapeutic dose. Thus this results in lower tumor control and higher complication probability. The purpose of this dissertation is to develop two individual systems to assess those geometric uncertainties. First, in order to assess machine related errors, a smartphone application for mechanical quality assurance (QA) of medical linear accelerators (LINAC) was developed. Second, in order to assess patient related motion errors, optical image-based motion tracking system using a stereo camera was developed. These systems were adopted to the clinic to test clinical feasibility following the accuracy and precision evaluation tests for each system. The geometric uncertainty assessment systems we developed can be used for the mechanical QA of medical accelerators and the evaluation of patients motion with proven accuracy and precision. Thus these systems have a strong potential of application in the clinic to provide precise radiotherapy by assessing geometrical uncertainties.