A multiple acquisition sequence for IMRT verification with a 2D ion chamber array.

This investigation deals with the implementation of a multiple acquisition (MA) sequence for radiotherapy beam verification with a 2-dimensional (2D) ion chamber array. The acquisition is carried out through multiple beam deliveries with the 2D detector array in different positions. The MA sequence is performed through remote-controlled movements of the treatment couch. In this work, the MA dose map of an intensity-modulated radiotherapy (IMRT) modulated beam is presented and compared to standard acquisition mode data and ion chamber measurements. The implementation of MA sequence increases the number of measurement points and therefore the efficiency of the detection system and the final imaging resolution. Results from this investigation show that the imaging resolution of the system used in standard acquisition mode can be increased up to 4 times. The procedure described in this work can be automated, including couch movements in the radiotherapy plan sent to the treatment workstation. Furthermore, this specific solution could be successfully applied to matrices of detector with a different construction design.