The IGRT process is similar to a typical radiation treatment, except that it includes an additional imaging step just prior to each daily treatment. Typically, after conducting a physical exam and a medical history review, the radiation oncologist determines an individualized course of treatment for each patient.
Most cases require a treatment preparation session. Special molded devices that help the patient maintain the same position every day are sometimes developed at this point. Colored, semi-permanent ink may be used to mark the patient's skin, to assist in positioning the patient for treatment by aligning the radiation equipment with the targeted area. A special CT scan in the treatment position is sometimes taken, for use as a reference image later on in the process. The treatment preparation session might take from thirty minutes to an hour and the CT scan might take an additional 15-30 minutes.
Following the CT scan, the radiotherapy treatment planning process usually takes several days. When the plan is complete, the patient is given an appointment to begin radiation treatments.
The first treatment session is sometimes longer than subsequent ones so that additional X-ray films and checks can be done. A typical treatment session lasts about 15 minutes.
In the treatment room, the radiation therapist uses the marks on the patient's skin to locate the treatment area. The patient is positioned on a treatment table. Sometimes, special molded devices are used to help with rough positioning.
The radiation therapist leaves the treatment room and remotely controls a digital TheraView imaging system to fine-tune the patient's position and move the treatment couch into final position. The TheraView Imager rotates around the patient to take digital images of the targeted area. Usually two or more images are taken from different angles. A complete rotation of the machine may be used to generate a three-dimensional image. These images are then used to guide the final adjustments of the treatment couch.
Although the patient is alone in the treatment room, he or she can be seen on a television screen or through a window in the control room. The therapist can talk with the patient through an intercom. Patients do not see or hear the radiation and usually do not feel anything.