Diode arrays and QA of advanced techniques

Dosimetric verification of delivery for intensity-modulated radiotherapy (IMRT) treatment plans is critical to ensure accurate and safe patient treatments. Commonly, a point dose measurement using a calibrated ion chamber as well as a planar dose measurement using film was traditionally implemented for dosimetric quality assurance (QA) of treatment plans. However, new products have become commercially available in which both an absolute and coarse planar dose measurements can be acquired simultaneously by the use of an array of detectors - either ion chamber- or diode-based. Currently, two devices, MapCHECK and Delta⁴, utilize diode technology for planar dose measurements with Delta⁴ implementing an orthogonal biplanar arrangement versus the common singular plane. Both devices have been thoroughly clinically characterized with more published experience in the literature available for the MapCHECK due to the novelty of Delta⁴. In this review, an overview of basic diode dosimetry and both diode array systems is presented with an emphasis on our research and clinical experience of the Delta⁴.