At some point after treatment planning, the patient returns for
treatment delivery. During treatment, the patient is fitted with the
custom plastic mask (for cranial tumors) or body cradle (for spinal
tumors/lesions or other extracranial tumors such as lung or pancreas)
and lies on the treatment table.
Prior to beginning of the actual radiation treatment, the imaging
system acquires X-ray image of the patient position. This information,
compared with the information gathered with the CT scan, is used to
move the linear accelerator to the appropriate position by the robot.
This process is repeated at 50 to 200 different positions around the
patient to complete the treatment. At various intervals, the robot
stops and additional X-ray images are obtained, thereby allowing the
CyberKnife to track and compensate for small amounts of patient movement.
The entire process is painless, and it typically takes between 30 to
60 minutes to deliver all radiation beams for cranial treatments. Most
typically a patient can go home immediately upon completion and return
to normal activities. If the treatment prescription is for staged
(fractionated) radiosurgery, the patient will return on a separate
visit and repeat the above process for treatment delivery.