PD-0337 prostate IGRT using quantitative 3D ultrasound imaging: Intramodality US vs. MV imaging of implanted markers

To allow for high precision radiotherapy, imaging prior to a radiation session is performed in Image Guided Radiotherapy (IGRT). Electronic portal imaging (EPI) can visualise bony anatomy and fiducial markers (FM). However, for prostate cancer, visualising the organ itself is more desirable. Ultrasound (US) is a well known widely used diagnostic technique for qualitative imaging of soft tissues such as the prostate. Nowadays a quantitative intramodality 3D US system for radiotherapy image guidance is available (Clarity system, Elekta, Stockholm, Sweden). In this work a comparison was performed between 3D US image guidance and the currently used prostate localization procedure.