Radiation oncology uses special kinds of energy waves or particles to fight cancer. Radiation therapy is used in several ways depending on the type and location of the cancer. Certain levels of radiation work to destroy cancer cells or prevent cells from growing or reproducing. This treatment may provide a cure for cancer, control the disease or help relieve its symptoms.
At Massey, radiation therapy usually begins with these procedures:
- Simulation process – after a physical examination and a review of your medical history, your treatment team “maps” out the position you will be in for each treatment and the exact location on your body (referred to as treatment field or port) where the radiation will be given (the simulation process). Sometimes, the area on your body that requires treatment will be marked to make sure radiation is given properly. The treatment team also may make molds, headrests or other devices that help to position you during your treatment. Imaging studies also may be performed during the simulation process to help plan how to direct the radiation during your treatments.
- Treatment plan – once the simulation process is completed, the radiation oncologist will determine your treatment plan, including the type of machine to use, the amount of radiation that is needed and the number of treatments that will be given.
Here at Massey, radiation therapy is given through different methods, depending on the type of cancer, the location of the cancer and the patient’s health. Sometimes radiation therapy is used in combination with other treatments. The following includes some of the different types of radiation therapy with brief explanations of their goals:
- Stereotactic radiation – this type of radiation treatment has been an important development in the treatment of brain cancer. By using specialized high precision immobilization devises, such as head frames and mold masks, very narrow radiation beams can precisely deliver high doses of radiation directly to the tumor site while sparing the adjacent tissues. Depending on the size and location of the tumor, this type of radiation may be used alone or in combination with other types of external beam treatment. Research is currently being conducted at VCU on techniques to deliver this type of radiation to small tumors outside of the brain, including sites in the lung and liver, where normal organ motion has been a limiting factor in being able to reduce the size of a tumor treatment area.
- Three-dimensional conformal radiation therapy – this type of treatment planning and radiation delivery technique uses a sophisticated computer program and various imaging studies, such as a CT, PET and MRI, to create three-dimensional images and mapping for targeting and accurately identifying the tumor. This detailed image planning allows the radiation beam to be formed to the exact size and shape of the tumor, and moreover to allow beams to be designed that may enter the body from a wide range of 3-D orientations. Higher doses of radiation can then be delivered directly to the tumor with lower radiation exposure to surrounding critical organs and normal tissue.
- Intensity modulated radiation therapy – a more specialized form of 3-D-CRT, IMRT uses thousands of individual beams of radiation to precisely deliver different doses of radiation to the tumor while lower doses are delivered to the surrounding target area. The IMRT techniques, many of which have been developed at VCU and used in commercial systems, allow for very high conformality of doses around irregularly shaped tumors. Moreover, IMRT allows the clinicians to establish differing doses to various zones around tumor volumes in order to provide simultaneous integrated boosting, which is highly effective at improving the biological effectiveness of the radiation therapy. Improving biological effectiveness of radiation therapy and incorporating image-guided precision of our delivery process has been a successful and important part of our clinical research program at VCU Medical Center.
- Image-guided radiotherapy – enables radiation oncologists to target the external beam to a fraction of a millimeter.
Massey’s image-guided treatment center uses a powerful linear accelerator — Varian’s 23EX Clinac — to deliver radiotherapy doses at least 60 percent faster than conventional accelerators. This shortens the length of time patients need to spend undergoing treatment. In addition, the Trilogy equipment rotates 360 degrees around the patient to deliver radiotherapy treatments from many angles, allowing clinicians to deliver treatments with unprecedented accuracy.
The Trilogy System combines imaging and treatment technologies, and can be used to deliver the widest range of external beam radiotherapies: 3-D conformal radiotherapy, IMRT, stereotactic radiosurgery, fractionated stereotactic radiation therapy and intensity-modulated radiosurgery for cancer and neurosurgical treatments.
By incorporating sophisticated technologies for shaping the radiation beam, the Trilogy System targets the radiation dose precisely on the region of abnormality. By changing the beam shape over time while delivering the radiation, doctors achieve very fine control over how and where the radiation is administered.
The Trilogy Center team has enhanced our system with additional technologies for positioning patients accurately including:
- A special X-ray imager to check the patient’s position prior to treatment and monitor the position of the targeted area during treatment.
- An optical guidance system with infrared cameras that continuously monitor the patient’s position to provide therapists with real-time feedback about any changes in a patient’s position.
At VCU Massey Cancer Center, we are the first facility in the world to combine the Trilogy System with the ExacTrac® respiratory gating technology that coordinates treatment with movements caused by the patient’s breathing.
- Internal radiation (brachytherapy, implant radiation) – a high dose of radiation is given inside the body as close to the cancer as possible. The radiation treatment may be swallowed, injected or implanted directly into the tumor. Some of the radioactive implants are called “seeds” or “capsules.” Internal radiation involves administering a higher dose of radiation in a shorter time span when compared with external radiation. Some internal radiation treatments stay in the body temporarily; other internal treatments stay in the body permanently, although the radioactive substance loses its radiation within a short period of time. In some cases, both internal and external radiation therapies are used.
Radiation therapy is a painless cancer treatment, though it can irritate skin. The biggest risk of radiation therapy involves potential damage to normal cells, in addition to the cancerous cells. This damage to the normal cells can cause some side effects, which will be monitored and treated by your cancer treatment team.
As each person’s individual medical profile and diagnosis is different, so is his or her reaction to treatment. Side effects may be severe, mild or absent. Be sure to discuss with your cancer care team any and all possible side effects of treatment before the treatment begins.
Many new radiation techniques are being used and studied to find more effective treatments for cancer. Some of the more promising therapies are described below.
- Radiation and chemotherapy in combination – depending upon the particular type of cancer, physicians may choose to combine radiation with chemotherapy. Radiation may help to shrink tumors before surgery, for example, and chemotherapy may be used afterward to kill cancer cells not removed by surgery. Research is being conducted in this area.
- Endovascular brachytherapy – the use of interventional procedures such as angioplasty, stents and other procedures has increased greatly in the past 20 years. Angioplasty and stents are used to open blocked areas in blood vessels. Unfortunately, newly opened areas in blood vessels may close after an angioplasty or stent procedure. However, research studies have shown that the use of radiation at the site of angioplasty or stent decreases the chance of vessel closure following these procedures. Endovascular brachytherapy continues to be studied at this time.
- Intraoperative radiation – the use of radiation during surgery to treat cancerous tumors or other forms of cancer. This treatment decreases the area of affected tissue because a larger dose of radiation can be used. For some people, intraoperative radiation improves the outcome of their treatment. Intraoperative radiation may be used in addition to external radiation.
- Thermoradiotherapy (hyperthermia) – scientific experiments have shown that the use of high temperatures localized at the treatment site improves the success of radiation therapy. Further research is currently being conducted to learn more about this treatment option.
- Radioimmunotherapy – this type of radiation therapy involves using antibodies “tagged” with a special substance. These tagged antibodies recognize tumor cells and bind with them. By doing so, the antibodies bring cancer medication in contact with the tumor. Radioimmunotherapy may be helpful in treating cancer that has spread to other parts of the body.
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