Types of Radiation

External Beam Radiation Therapy

During external beam radiation therapy, a beam (or multiple beams) of radiation is directed through the skin to kill cancer cells and shrink tumors.   To minimize side effects, the treatments are typically given five days a week, Monday through Friday, for several weeks.   This allows enough radiation to get into the body to kill the cancer, while giving healthy cells time to recover.

The radiation beam is generated by a machine called a linear accelerator.  The linear accelerator, or linac, is capable of producing high-energy X-rays or electrons for the treatment of your cancer.   Using treatment planning computers and software, the care team is able to control the size and shape of the beam, as well as how it is directed at your body, to effectively treat your tumor while sparing the surrounding normal tissue.

Intensity Modulated Radiation Therapy

Intensity Modulated Radiation Therapy, or IMRT, is a specialized form of radiation therapy that allows radiation to be more exactly shaped to fit the tumor.   With IMRT, the radiation beam can be broken up into many “beamlets”, and the intensity of each beamlet can be adjusted individually.   Using IMRT, it may be possible to further limit the amount of radiation received by healthy tissue near the tumor.   In some situations, this may also safely allow a higher dose of radiation to be delivered to the tumor, potentially increasing the chance of a cure.

Image Guided Radiation Therapy

Our centers utilize IGRT (Image Guided Radiation Therapy) to help better deliver the radiation to the cancer since tumors can move between treatments due to differences in organ filling or movements while breathing.   IGRT involves radiation treatment guided by imaging, such as CT, ultrasound, or x-rays, taken in the treatment room just before each radiation treatment is administered.

Stereotactic Body Radiation Therapy (SBRT)

SBRT is one of the most advanced forms of radiation therapy available for cancer patients.  SBRT incorporates a specially designed mapping system that tracks the exact location of the target tumor with pinpoint accuracy.   This technology allows us to treat targeted areas with high doses of radiation in fewer treatments, while damaging less healthy tissue.  SBRT delivers a high dose of radiation in a shorter amount of time than traditional treatments.  Most SBRT patients receive one to five treatments, over the course of several days (some patients may require a few more).

SBRT is used to treat small tumors that cannot be removed surgically or treated with conventional radiation therapy.   Patients with tumors that are small and few in number are the best candidates for SBRT. For patients with small lung tumors who are not candidates for surgery due to tumor size or location or other factors, SBRT may be an option.  Not all patients are candidates for this treatment. Your radiation oncologist can tell you if SBRT is an option for you.

High Dose Rate Brachytherapy (HDR):

Temporary, or high-dose-rate (HDR) brachytherapy, uses a single small radioactive source to deliver radiation via small tubes or catheters, which are inserted into the body by the radiation oncologist. The treatment is done under anesthesia in an outpatient setting. The tubes remain in place for one to two days only.

Once the treatment is complete, the tubes are taken out. HDR brachytherapy is temporary and once the tubes are removed, there is no radioactivity left in the body.


The CyberKnife System is the most advanced alternative to surgery for the treatment of cancerous and non-cancerous tumors throughout the body, including tumors in the brain, prostate, lung, pancreas, liver, spine, head and neck in just one to five targeted radiation sessions. The system provides real time tracking of tumors using constant imaging during treatment.

Utilizing the CyberKnife, we are able to provide stereotactic radiosurgery in the brain without the use of a frame screwed into the skull (as is required by a Gamma Knife or standard linear accelerator).

The CyberKnife System delivers high doses of radiation with sub-millimeter accuracy, which enables treatment to be complete in typically one to five days, compared to the weeks or even months required for treatment with other technologies.  The CyberKnife System’s ability to deliver radiation with pinpoint precision minimizes side effects by sparing exposure to surrounding tissues. With highly precise radiation delivery, patients generally experience fewer side effects and can quickly return to their normal daily routine.

*Some content provided by the American Society for Radiation Oncology.

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