ABSTRACT
This chapter describes in-room imaging with ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), fluoroscopy, and combinations of these. For the last 20 years, radiotherapy has evolved from a two-dimensional (2D) approach using radiographic films to an approach where the treatment is based on three-dimensional (3D) imaging showing the target volumes and the normal tissues. This development is seen for both external beam radiotherapy (EBRT) and brachytherapy. In-room imaging with US has been used for several decades, especially for prostate brachytherapy where transrectal ultrasound (TRUS) is used. Modern software technology facilitates intraoperative procedures enabling interactive treatment planning techniques. In cervical cancer brachytherapy, US is primarily used to ensure a safe applicator placement, while MRI is the recommended modality for treatment planning. In-room imaging using x-ray imaging and fluoroscopy offer the unique potential possibility of verifying the treatment setup and treatment delivery in real time as the high-dose rate (HDR) source can be directly imaged.
