Radiation Therapy

NHRMC Zimmer Cancer Center Renovation

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You and your doctor will work together to develop a plan for your treatment. If your cancer can be treated with radiation, you will be referred to a radiation oncologist — a doctor who specializes in treating patients with radiation therapy.

Radiation therapy, or radiotherapy, is the use of various forms of radiation to safely and effectively treat cancer and other diseases. Radiation therapy works by damaging cells. Normal cells are able to repair themselves, whereas cancer cells cannot. New techniques also allow doctors to better target the radiation to protect healthy cells.

Radiation oncologists may use radiation to cure cancer, to control the growth of the cancer or to relieve symptoms, such as pain.

Your radiation oncologist will work with your primary doctor and other cancer specialists, such as surgeons and medical oncologists, to oversee your care. He or she will discuss the details of your cancer with you, the role of radiation therapy in your overall treatment plan and what to expect from your treatment.

Radiation and Other Treatment Therapies

Sometimes radiation therapy is the only treatment a patient needs. At other times, it is only one part of a patient’s treatment. For example, prostate and larynx cancer are often treated with radiotherapy alone, while a woman with breast cancer may be treated with surgery, radiation therapy and chemotherapy.

Radiation may also be used to make your primary treatment more effective. For example, you can be treated with radiation therapy before surgery to help shrink the cancer and allow less extensive surgery than would otherwise be needed, or you may be treated with radiation after surgery to destroy small amounts of cancer that may have been left behind.

Sometimes, the overall goal is to slow down the cancer as much as possible. In other cases, the goal is to reduce the symptoms caused by growing tumors and to improve your quality of life. 

Types of Radiation Therapy

Intensity-Modulated Radiation Therapy (IMRT)

Intensity modulated radiation therapy, or IMRT, is a specialized form of 3D-CRT 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 that is received by healthy tissue near the tumor. In some situations, this may also allow a higher dose of radiation to be delivered to the tumor, potentially increasing the chance of a cure.

Brachytherapy

Brachytherapy is minimally invasive. Brachytherapy is more effective at destroying cancer cells while minimizing damage to surrounding healthy tissue than conventional chemotherapy. You may have this therapy to shrink your liver tumor enough that it can be removed with surgery.

To remove this liver tumor, your doctor makes a small incision in your upper thigh and threads a thin tube through your blood vessels to the major artery to your liver. Through the tube, your doctor releases millions of microscopic radioactive spheres. These spheres get trapped in the tiny blood vessels inside your liver tumor and give off radiation to destroy the tumor from within your body.

You have a PET/CT scan before and after brachytherapy to determine if the treatment helped to shrink your tumor enough to remove it surgically.

Image Guided Radiation Therapy (IGRT)

Radiation oncologists use image guided radiation therapy, or IGRT, 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 conformal radiation treatment guided by imaging, such as CT, ultrasound or X-rays, taken in the treatment room just before the patient is given the radiation treatment. All patients first undergo a CT scan as part of the planning process. The imaging information from the CT scan is then transmitted to a computer in the treatment room to allow doctors to compare the earlier image with the images taken just before treatment.

During IGRT, doctors compare these images to see if the treatment needs to be adjusted. This allows doctors to better target the cancer while avoiding nearby healthy tissue. In some cases, doctors will implant a tiny marker in or near the tumor to pinpoint it for IGRT.

Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiation Therapy (SBRT)

Stereotactic radiotherapy is a technique that allows your radiation oncologist to precisely focus beams of radiation to destroy certain types of tumors.

Since the beam is so precise, your radiation oncologist may be able to spare more healthy tissue. This additional precision is achieved by using a very secure immobilization, such as a head frame used in the treatment of brain tumors. Stereotactic radiotherapy is frequently given in a single dose (sometimes called radiosurgery) although certain situations may require more than one dose.
In addition to treating some cancers, radiosurgery can also be used to treat malformations in the brain’s blood vessels and certain noncancerous (benign) neurologic conditions.

Sometimes a high dose of stereotactic radiotherapy can be focused upon a tumor outside the brain and given in a few treatments (typically three to eight). This form of treatment is called stereotactic body radiation therapy.

Three-Dimensional Conformal Radiation Therapy (3D-CRT)

Tumors are not regular — they come in different shapes and sizes. Three-dimensional conformal radiation therapy, or 3D-CRT, uses computers and special imaging techniques to show the size, shape and location of the tumor. Computer assisted tomography (CT or CAT scans), magnetic resonance imaging (MR or MRI scans) and/or positron emission tomography (PET scans) are used to create detailed, three-dimensional representations of the tumor and surrounding organs. Your radiation oncologist can then precisely tailor the radiation beams to the size and shape of your tumor. Because the radiation beams are very precisely directed, nearby normal tissue receives less radiation and is able to heal quickly.