Cone beam CT is a type of image guidance where the radiation machine will spin around you one to two times before your treatment is delivered. Images (similar to CT images) are produced and reviewed by your doctor at the control panel just before treatment is delivered. This allows for fine tuning of the aim of the radiation beams for your treatment on a daily basis by the physician and results in more accurate delivery when additional precision is necessary in some treatment cases (typically used for head and neck and prostate cancer treatment).
The Oregon Clinic