External beam radiation is a painless procedure that usually takes less than 30 minutes. It is similar to getting an X-ray. Conventional treatment is given in small doses daily, five days a week for several weeks at a time. Your doctor will determine the length of your treatment based on many factors including your tumor size and location, as well as the technique used to deliver your treatment.
Image guided radiation therapy (IGRT) uses CT (computerized tomography) or X-ray to guide beams of radiation by directing the treatment to the tumor while avoiding nearby healthy tissue. Because imaging is used in real time, your radiation team can better control the precision of treatment by comparing images to ensure the most accurate delivery of radiation.
Three-dimensional conformal radiation therapy (3D-CRT) is a type of radiation treatment that uses diagnostic imaging such as CT or MRI (magnetic resonance imaging) to create a specialized treatment plan designed specifically to target your tumor.
Intensity modulated radiation therapy (IMRT) is a type of 3D-CRT with more sophistication that allows radiation to be formed to the exact dimensions of your tumor. In addition, the intensity of the beam can be altered so that damage to healthy, normal tissue is further minimized.
Stereotactic body radio surgery (SBRT) is a sophisticated type of radiation treatment that precisely focuses multiple beams of radiation to the tumor from several different angles. Unlike conventional treatment, with SBRT large doses of radiation can be delivered to the entire tumor, typically in one to five treatments that may last as long as 30 minutes each.
Stereotactic radio surgery (SRS) is similar to SBRT, but given in one single dose and generally to the central nervous system, which consists of the brain and spinal cord.
Brachytherapy is also known as internal radiation. Small sources of radiation are placed in or around the tumor and may be permanent or temporary, depending on the type of cancer and treatment indicated.
High-dose rate (HDR) brachytherapy is typically delivered in high doses over a couple of treatments. Intracavity HDR is often used for breast, cervical and vaginal cancers. The radiation is delivered to the site from the cavity left by the recently removed tumor.
Low-dose rate (LDR) brachytherapy is used to treat some types of prostate cancer. The radioactive seeds, which are about the size of a rice grain, are implanted at the tumor site through catheters. The seeds remain near the tumor. Over time, the seeds become nonradioactive.