Electronic Portal Imaging Device Dosimetry for IMRT: a Review on Commercially Available Solutions

Much research has been conducted about the utilization of electronic portal imaging devices (EPID) for dose verification during radiotherapy treatment. Currently a number of commercial solutions are available; Portal Dosimetry, EPIDose, Epiqa, Dosimetry Check, and EPIgray software. Results from separate studies on clinical applications of these solutions are published. The objective of this paper is to review the accuracy of these dosimetry solutions when used for intensity modulated radiotherapy technique (IMRT). Although each solution has a different approach to dose verification, most of the IMRT dosimetry verification results are highly satisfactory. However, performance of one solution is less satisfactory when the patient-couch attenuation occurs. Moreover, none of these solutions correct the backscatter effect resulted from supporting arm. In addition, there are no comparative studies currently available about the accuracy of these solutions except one paper that compared Portal Dosimtery and EPIDose reporting the major differences between these systems. Further studies are needed to compare the accuracy of these commercially available EPID dosimetry solutions.