Types of Radiation Therapy
Several forms of radiation treatment are available.
External beam radiation
Patients can receive external beam radiation treatments from one of our linear accelerators. The radiation is beamed into the tumor from outside the body for approximately two to three minutes for each treatment.
Image-guided, intensity-modulated radiation therapy
Intensity-modulated radiation therapy (IMRT) is used to treat patients with prostate cancer, cancers of the head and neck, and cancer at the base of the skull or parts of the brain. IMRT allows the tumor to be targeted with higher doses of radiation, particularly in the vicinity of critical structures, with greater potential for a cure and greater likelihood of limiting late complications from treatment. The incorporation of image-guided technology with IMRT allows doctors to track tumor position and location while the patient is actually on the treatment table. Image-guided IMRT affords more precise coverage, allowing doctors to respond immediately to any tumor movement and, if necessary, to recalculate the radiation fields during the treatment session.
A precise, single dose of radiation is delivered in cases where tumors of the brain are adjacent to critical areas, such as the brainstem, eyes or optic nerves. Stereotactic radiosurgery further minimizes the side effects associated with conventional radiation. A neurosurgeon is present during treatment to attach a halo-like frame to the scalp to assist with proper positioning. CyberKnife is a robotic system for stereotactic radiosurgery.
Similar to stereotactic radiosurgery, lower doses of focused radiation are delivered with pinpoint accuracy during a series of treatment sessions that usually last between eight to 10 days. This method of multiple treatments is called “fractionation.” During treatment, a halo-like frame held in place by a mouthpiece helps position the head for treatment.
Total body irradiation (TBI)
Patients who are awaiting a bone-marrow or stem-cell transplant can receive this important preparatory treatment. When combined with chemotherapy, TBI is used to suppress the immune system and eliminate any pre-existing tumor cells. TBI treatments can last anywhere from 20 to 60 minutes. Additional time may be needed for treatment planning and simulation. The specific amount of radiation the doctor prescribes is divided into a number of doses and may be given one or more times a day for one to four days, depending on the individual case. A specially designed stand may be used for support during treatment. The stand includes a bicycle seat and hand grips for support. Alternatively, a patient may be treated lying on a stretcher.
Prostate seed implants (brachytherapy)
An advanced form of radiation therapy, also called brachytherapy, uses radioactive seed implants to treat early prostate cancer. In this minimally invasive procedure, doctors use ultrasound-guided needles to insert tiny radioactive seeds (Iodine 125 or Palladium 103) into the prostate gland. The seeds emit low-energy gamma rays that specifically target cancer cells in the prostate. The seeds lose 90 percent of their radioactivity within a few months following the implant, and within a year they are considered inert or not active.
Helen F. Graham Cancer Center & Research Institute
Concord Health Center