Feasibility Study of CBCT for IGRT in Cancer Patients

Cone beam computed tomography (CBCT) is an imaging technology that is incorporated into many modern radiation therapy systems. The quality of conventional CBCT is good enough to align patients for their daily radiation therapy but CBCT images have poor contrast and are susceptible to imaging artefacts that limit their usability for other tasks in the radiation therapy workflow. Varian Medical Systems, the sponsor of this study, has developed new CBCT imaging technology called HyperSight that so far has demonstrated increased image quality compared with conventional CBCT images. This new HyperSight CBCT imager has previously been built into Varian Halcyon and Ethos treatment machines, where the imager is enclosed in a ring that rotates around the patient. Now, HyperSight has been built into a Varian treatment machine, called TrueBeam, where the imager is mounted on a C-shaped arm that rotates around you to acquire an image. This study is being done to evaluate the image quality of HyperSight CBCT compared to conventional CBCT images, and to determine whether HyperSight CBCT can improve the process of delivering radiation treatments. The goal of this study is to collect images from this new HyperSight-TrueBeam CBCT imager from a variety of patients and locations in the body. The images will be analyzed to determine whether their quality is high enough to use for tasks other than positioning patients for treatment. For example, the study will determine whether the HyperSight images could be used to calculate a radiation plan.