Planning. Before beginning a TomoTherapy treatment, the doctor uses 3D images from a combination of scanning technologies (such as CT and MRI) and special software to establish the precise contours for each treatment volume (tumor) and any regions at risk (sensitive organs or structures). The doctor then decides how much radiation the tumor should receive, as well as acceptable levels for surrounding structures. The TomoTherapy treatment system calculates the appropriate pattern, position and intensity of the radiation beam to be delivered, to match the doctor’s prescription as closely as possible.
Patient positioning. As both a treatment delivery machine and a CT scanner, the TomoTherapy system allows doctors to take a CT scan just before each treatment. With the scan, they can verify the position of the tumor and, if necessary, adjust the patient’s position to help make sure radiation is directed right where it should be.
Precise treatment delivery. The TomoTherapy treatment system delivers radiation therapy with a spiral delivery pattern (TomoHelical™) or discrete-angle approach (TomoDirect™). Photon radiation is produced by a linear accelerator (or linac for short), which travels around the patient and moves in unison with a device called a multi-leaf collimator, or MLC, that shapes the beam. Meanwhile, the couch is also moving—guiding the patient slowly through the center of the ring.