The Value of Radiation TherapyThe Value of Radiation Therapy
Radiation therapy is one of the three most commonly used cancer treatments along with surgery and chemotherapy. In radiation therapy, X-rays, gamma rays and other sources of radiation are delivered directly to the tumor site in the body. The radiation destroys the cancer cells' ability to reproduce. When these damaged cells die, the body naturally eliminates them. Curative radiation therapy is used to treat cancer and palliative radiation therapy can be administered to help reduce symptoms such as pain from cancer that has spread to other parts of the body.
Today, about 50 to 60 percent of cancer patients are treated with radiation at some time during their disease. While radiation impacts both cancer cells and surrounding normal cells, the majority of normal cells are able to easily recover and go on to function completely normally. Continuous advancement in radiation technology throughout the years has led to fewer side effects and increased protection of normal cell tissue.
There are different types of radiation therapy. When most people receive radiation, it is delivered externally from a machine that is outside the body. This type of treatment is usually given on an outpatient basis. Three-dimensional (3D) conformal radiation therapy uses computer technology to allow doctors to more precisely target a tumor with radiation beams (using width, height, and depth). There are now a number of techniques that are used to deliver this type of external radiation therapy.
A 3D image of a tumor can be obtained using computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), or single photon emission computed tomography (SPECT). Using the information from the image, programs design radiation beams that match the shape of the tumor.
Intensity-modulated radiation therapy (IMRT) is a new type of 3D conformal radiation therapy that uses radiation beams with different intensities to deliver different doses of radiation to smaller areas of tissue at the same time. The technology allows for the delivery of higher doses of radiation within the tumor and lower doses to nearby healthy tissue.
Another common type of radiation therapy is internal radiation, or brachytherapy, whereby radiation is placed into the body just next to, or inside, the tumor. The radiation source is usually sealed in a small holder called a seed implant.
Radiation oncologists also use image-guided radiation therapy (IGRT) or image-guided adaptive radiation therapy (IGART), to help more effectively deliver radiation therapy to cancer cells. It is most often used in areas of the body that are prone to movement and uses three-dimensional imaging to improve the accuracy of the delivery of the treatment. Since tumors can actually move between treatments, IGRT can be very helpful because the radiation oncologist can image the tumor immediately before or even during the time radiation is delivered while the patient is positioned on the treatment table. Adjustments are made to the patient's position and radiation beams and the radiation is more precisely aimed to target the tumor.
Each year, countless cancer patients are cured after being treated with radiation therapy alone or in combination with other treatments.
A treating physician may choose a particular type of radiation and delivery based on factors including the patient's type of cancer, its location, how far into the body the radiation will need to go, the patient's general health and medical history, and whether the patient will have other types of cancer treatments. In any treatment situation, it is important for patients and their physicians to engage in open communication with one another in order to determine the best treatment option for the individual patient based on their particular situation and medical history.