Lag correction model and ghosting analysis for an indirect conversion flat panel imager

Abstract

Cone Beam Digital Tomosynthesis (CBDT) is a new approach that was proposed recently for rapid tomographic imaging of soft-tissue targets in the radiotherapy treatment room. One of the potential problems in implementing CBDT using, e.g., megavoltage (MV) x rays is the possibility of artifacts caused by image lag and ghosting of the x-ray detector used. In this work, we have developed a model to correct for image lag for indirect-conversion flat panel imagers (FPIs) used for MV-CBDT. This model was based on our measurement and analysis of image lag in an indirect-conversion FPI using a 6MV x-ray beam. It has been demonstrated that image lag can be corrected. In addition, the ghosting effect has been measured for the indirect-conversion FPI and was found to be insignificant.