Your Treatment: Treatment Options
- External Radiation Therapy
- Brachytherapy/Implants
- Intensity Modulated Radiation Therapy
- Endocavitary Radiation Therapy
- Stereotactic Radiosurgery
- Gamma Knife
- Intravascular Brachytherapy
- Hyperthermia
- Radio Immunotherapy
- Cancer Information
External Radiation Therapy
This is the most common type of radiation therapy. A machine called a linear accelerator is used to direct high energy X-rays called photons or electrons to the tumor and some of the normal tissue around it.
Before receiving treatment you should know:
- Radiation therapy is not painful — you cannot see or feel the treatment.
- You are required to lie very still for the short duration of treatment.
- The number and pattern of treatments is not an accurate way to judge the severity of your disease. Please ask the physician if you have concerns.
- For your treatments, you will be lying on a table that rises up in the air. The treatment machine rotates around you.
- You are not radioactive after you receive external treatments nor do you pose any health threat to your family and friends
We encourage you to lead your life as normally as possible. Always ask, if you have questions. You may hear something about radiation therapy that concerns you. Your physician is always prepared to talk over such matters with you.
Brachytherapy/Implants
In addition to treating cancer with X-ray photons and electrons directed to the tumor area from outside the patient, the Department of Radiation Oncology also uses procedures that allow the therapeutic radiation to be directed from inside the patient, often close to or within the tumor. This type of therapy is called “brachytherapy” or “radiopharmaceutical therapy,” depending on whether the internal radiation is delivered by sealed sources of radioactive material inserted in hollow tubes or catheters placed in the desired area, or by liquid radioactive chemical compounds which the patient drinks or receives through injection. These radioactive liquids are localized in the tumor area. Our brachytherapy program is one of the largest and most comprehensive in the United States, delivering nearly 1,000 implants annually.
Brachytherapy procedures carried out in the Department of Radiation Oncology include treatment of cancer of the vagina, cervix and uterus with radioactive cesium or iridium; treatment of tumors in the lung, esophagus and extremities with radioactive iridium; and treatment of cancer of the prostate with radioactive iodine and palladium. Our radiopharmaceutic therapy procedures include treating cancer of the thyroid with an orally administered salt solution of radioactive iodine, metastatic tumors of the bone with an intravenously injected solution of radioactive strontium or sumarium, and ovarian and cystic brain tumors with directly injected colloidal solutions of radioactive phosphorus. In addition, brachytherapy to coronary arteries for prevention of re-stenosis is performed at our facility.
Intensity Modulated Radiation Therapy
One of the most recent and exciting developments in radiation therapy is intensity modulated radiation therapy (IMRT). Using modern computer dose distribution optimization and dose delivery control, dose distributions can be designed and delivered that more completely spare critical structure, while delivering high doses to the tumors. The equipment uses a computer-controlled multileaf collimator. The radiation treatment is delivered while the accelerator rotates around the patient. The multileaf collimator leaves open and close according to a pattern determined by the computer to deliver the optimal dose distribution.
In the case where the leaves are pneumatically actuated, they make a clicking noise as the gantry rotates. Each treatment delivers dose to a 2 centimeter long region, so for treatments of longer tumors, multiple gantry rotations are required. After each rotation, the patient is precisely moved 2 centimeters and the next region is treated. It is very important that the patient remain still during the treatment, as a special immobilization system is used.
Endocavitary Radiation Therapy
Some patients with early rectal cancers are able to avoid radical surgery and colostomy with the use of endocavitary irradiation. This special treatment is a method of delivering a very high dose of radiation to a small cancer on the surface of the rectum. The treatments are given in very high doses every 2-3 weeks for a total of two outpatient treatments. This treatment is combined with conventional external beam radiation therapy (usually 25 radiation treatments given 7-8 weeks before the endocavitary radiation). The external treatments serve to shrink the rectal cancer and to attack cancer cells that might be in the lymph nodes around the rectum. The endocavitary treatment itself is given using a hand-held x-ray device. The colorectal surgeon and radiation oncologist together target the diseased site and deliver the therapy over a few minutes. In appropriately selected patients, the cure rate for this form of treatment may approach 90% or better. The best candidates for this procedure must have small, minimally invasive cancers.
Stereotactic Radiosurgery
Stereotactic Radiosurgery specifically refers to a procedure whereby x-ray
or gamma-ray radiation is aimed at a focal point. The dose distributions achieved
by these techniques assure large doses to the target volume and much lower doses
to the surrounding normal tissues. Stereotactic Radiosurgery is typically given
as a single treatment.
Stereotactic radiosurgery is a technique used to treat various brain diseases
by concentrating radiation very accurately within a small volume of the brain.
The technique may be used to irradiate a tumor, an arteriovenous malformation
or some other type of brain lesion. The procedure requires a team effort by
the neurosurgeon, neurosurgery nurse, diagnostic radiologist, radiation oncologist,
medical physicist, medical dosimetrist and radiation therapists. Sometimes an
anesthesiologist joins the team to put the patient, usually a child, to sleep
for the treatment. The treatment is usually given only once, but the entire
procedure may take all day.
In order to achieve a high degree of positional accuracy, a special device called a stereotactic frame must be used. It is attached to the patient' s head by the neurosurgeon early on the day of treatment. Images of the region to be treated are then obtained. These images are pictures that allow the physicians to see the location, size and shape of the disease to be treated. They also show the location of radiosensitive normal structures in the brain that are to be avoided during treatment. Computed tomograms (CT scans), magnetic resonance images (MRI), angiograms or more than one imaging method in combination may be used.
Once the images are obtained, they are transferred to a computer that is used for treatment planning. This may take one to several hours depending on the complexity of the treatment plan. During the treatment planning process, the sizes and directions of all radiation beams, and the dose to be given are determined by the neurosurgeon, radiation oncologist, physicist and dosimetrist. The stereotactic frame appears in the images as dots and their locations provide the coordinates to direct the radiation. Dose to the treatment volume and normal brain is calculated and displayed graphically on the computer screen. The computer simulates the treatment before it is actually given. A number of potential plans are compared. The best plan is chosen that maximizes the dose in the disease site but minimizes the dose to normal brain. In this way, we create a specific treatment plan, tailor-made for each patient. The computer then prints out a record that describes how the plan is to be performed on the radiation treatment machine.
Following computerized planning, the radiation treatment machine, a linear accelerator or the gamma knife, is made ready for the patient. The patient arrives in the treatment room, lies on a special motorized table and is lifted toward the treatment position. Then, the patient's head is attached to the radiation machine using the stereotactic frame. The head is moved very accurately into position. This puts the disease site where the radiation beams will be directed. The patient's position is double-checked by the neurosurgeon and physicist, during which the patient will hear the coordinates, or numbers, as they are being read from the treatment machine.
Once the patient position is verified, measurements are made with rounded metal rods that touch the skin lightly at various angles. All but the patient leave the room before the radiation beam is turned on. When the radiation beam is on, the patient will hear a humming sound coming from the machine. This is normal and provides an audible indication that the radiation beam is activated. The beam may be turned off and on repeatedly and the patient may be repositioned several times depending on the complexity of the treatment plan. During the entire treatment process, the patient is watched by the therapist who observes with two video cameras in the room. An intercom system also is used. The patient can signal to the therapist operating the treatment machine at any time to halt the treatment if needed.
After all locations are treated, the patient is removed from the treatment machine and the stereotactic frame is removed. The patient then goes with the neurosurgery team to an observation area.
Gamma Knife
Gamma knife treatments allow the stereotactic therapy to be done in less time.
In addition, the gamma knife can treat very small lesions (4-5 millimeters)
and functional neurologic disorders such as epilepsy, trigeminal neuromalgia,
and others.
For more information
Intravascular Brachytherapy
Cardiologists and radiation oncologists have discovered that the placement of a radioactive source into a blood vessel will prevent it from re-occluding or re-stenosing following an angioplasty or dilation procedure. Physicians and medical physicists from Washington University work with cardiologists to deliver this important treatment to prevent future angina or heart attacks in patients with coronary artery disease.
Hyperthermia
Heat has been known to be an effective treatment against a number of cancers. When combined with radiation therapy, there may be enhancement of the anti-cancer effects. These treatments are used for advanced cases of breast cancers.
Radio Immunotherapy
Antibodies directed at the cell surface of some cancers have been linked to radioactive atoms. These antibodies seek and attach themselves to malignant cells and deliver a toxic radiation dose to the tumor. Currently these treatments are available for some lymphomas.
Cancer Information
We encourage you to speak with your doctors about your disease and treatment. In an effort to be helpful to you and present objective, unbiased information about cancer, we have provided website resources listed below. Remember that this information is not a replacement for the advice of your physician.
