What Is the Goal of Radiation Therapy?
The goal of radiation therapy depends on your specific type of cancer and your overall health. Generally, radiation therapy is designed to achieve one or more of the following results:
- Stop the growth of cancer cells to reduce their size before surgery or stop their growth after surgery.
- Improve your quality of life. Even if it’s not possible to cure certain cancer cases, radiation therapy may still improve symptoms and provide relief from pain and discomfort.
- Reduce the possibility of metastases, or disease spreading to other locations or organs within the body.
How Do I Get Radiation Therapy?
Radiation therapy is given in doses measured in grays or centigrays for several weeks. Radiation may be delivered either externally or internally.
External radiation is the most commonly used type. In external radiation, high-energy X-rays are directed at the cancer cells from the outside of your body.
Internal radiation, also called brachytherapy, is delivered from within your body in the form of precise amounts of radioactive material in an implanted device such as a catheter or other type of applicator. The radioactive material remains in place for the time required to destroy the cancer cells. That may be a short period of time or the material may be implanted permanently.
How Do Doctors Target the Radiation Therapy?
Today’s advanced technologies combine radiation delivery with different types of imaging, which allows the radiation oncologist to see a picture of the area to be irradiated. This means that the oncologist can more precisely target tumors with the radiation. More precise targeting results in a smaller area of healthy cells exposed to the radiation, which means fewer side effects. Two examples of advanced external radiation technologies are:
- Intensity Modulated Radiation Therapy (IMRT)
- Image-Guided Radiation Therapy (IGRT)
Intensity Modulated Radiation Therapy (IMRT) is an external radiation therapy that uses an imaging technology, such as Computed Tomography (CT), to build three-dimensional images of the treatment area. The oncologist can then make a treatment plan map to deliver tightly focused radiation beams directly to the tumor without needles, tubes, or catheters. Varying the intensity of the beams maximizes the amount of radiation delivered to the cancer cells while minimizing the effect on surrounding healthy cells.
Image-Guided Radiation Therapy (IGRT) is another external therapy. It uses ultrasound technology — called BAT®, or Bi-mode Acquisition and Targeting — to help locate the tumor prior to radiation therapy. BAT combines ultrasound with a 3D tracking system to pinpoint the tumor quickly and accurately, reducing the amount of healthy tissue exposed to radiation. BAT® is particularly effective on smaller or odd-shaped tumors.
High Dose Rate (HDR) brachytherapy is an advanced treatment for internal radiation. Like IMRT and IGRT, HDR allows doctors to deliver precise radiation therapy to your tumor. HRD is frequently used to treat cervical and uterine cancers and certain kinds of lung and esophageal cancers. Recently, it has also proven effective in treating early stage prostate cancer.
What is a Radiation Therapy Session Like?
A radiation therapy team consists of a radiation oncologist, a radiation therapist (who delivers the radiation therapy), physicists and dosimetrists, who all work together to develop your treatment plan and dosage calculations.
Before your treatment, you will have a simulation session where your team will map out the location(s) for your radiation therapy using either a CT scanner or x-ray positioning. Small reference marks called tattoos will be marked on your skin to help your team to target your treatment on a daily basis.
Your team will make sure you understand everything that will happen before you go in for your first treatment. Generally, you won’t feel anything during treatment, and many people arrange their treatment around their work schedules or other daily commitments.
Review a list of questions you may wish to ask your doctor about radiation therapy.