A typical course of radiation therapy lasts 5-7 weeks with daily treatment and it is paramount that the patient positioning be reproduced on a daily basis so that the tumor can accurately be targeted.
All linear accelerators (LINACs) at the UF Department of Radiation Oncology are equipped with gantry-mounted cone-beam CT (CBCT) systems. Image guidance with 3D CBCT is much more accurate and robust compared to conventional 2D portal image-based patient alignment. After the patient is positioned on the treatment couch, a CBCT is acquired and compared to the planning CT. The treatment couch is then adjusted so that the patient position is matched to the planning CT before treatment starts. Image-guided radiation therapy (IGRT) through the use of CBCT is the standard of care that we use for almost all of our patients.
For tumors in the chest and abdomen, tumor motion due to breathing is a concern. In these cases, a 4-dimensional CT (4DCT) simulation is typically performed in order to visualize the extent of tumor motion. Treatment plans are optimized so that tumor volume will be adequately covered based on the extent of tumor motion. During treatment, a camera system is used to monitor patient movement and treatment can be paused if the movement is outside a pre-defined range. The department is equipped with two state-of-the-art camera systems: an AlignRT® Advance system and a C-RAD Catalyst system. These surface-based tracking systems allow for accurate positioning and tracking of patients during treatment and will be most beneficial if tumor motion is suspected.
