Radiation Therapy

Radiotherapy or radiation treatment is the use of x-rays, electrons or gamma rays to treat cancer. Radiation can cure or control cancer by inhibiting the cancer cells from dividing or reproducing. About fifty or sixty percent of patients with cancer will require radiation at sometime during their lifetime. Radiation is a safe and effective form of treatment for patients of all ages. Please remember that there have been vast improvements in the equipment and delivery of radiation treatment over the last 20 to 30 years.

The radiation oncologist is the medical doctor in charge of a patient's radiation treatment. He or she prescribes and plans the radiation course that patients will be taking. He/she will also be monitoring patients while they are undergoing treatment and will be providing individualized quality care. Any side effects from the radiation will be recognized and treated by the radiation oncologist. The other members of the medical team include the medical physicist, the radiation therapist, and the dosimeterist.

The job of the medical physicist is to ensure the proper running of the machinery and performs regular calibrations and checks of the machine that will deliver the radiation.
The radiation therapist is the person who delivers the radiation each day and will be working under the orders and the prescription of the radiation oncologist.
The dosimeterist calculates the doses of radiation at various points in the body.

Patients may also encounter a registered nurse, dietitian, and social worker, during their course of treatment. These individuals will play a big role in the overall care.

The goal of radiation can be:

Curative or radical - Radiation can be a very effective treatment for prostate cancer
Palliative, that is, to alleviate or reduce symptoms of pain
Adjuvant which is a treatment that is designed to reduce the risk of tumor recurrence. Radiation can be used after surgery for breast cancer in order to reduce the risk of the cancer returning.

There are basically two types of radiation treatment:

External radiation
Brachytherapy, or radiation at a short distance.

A patient may receive one or the other, or a combination of both.

Steps in radiation treatment:

Consultation: At the beginning, the patient will be seen by the radiation oncologist for a consultation. During the consultation, the radiation oncologist will perform a history and a physical examination. he will review all the pertinent data and all of the investigations that have been performed. he may also request other tests or consultations to be made.

Simulation: The next step is simulation or treatment planning. After the consultation, the radiation oncologist will formulate a treatment plan. Here, the patient comes to the radiation department and lies down on a table under a machine, called a simulator. Various immobilization devices may be necessary, such as a head rest or a face mask, in order to make sure the patient is positioned correctly and in the same way for each treatment. There will be various markings that will be made on the skin and various x-rays will be taken.

Photographs may also be taken and this will help the radiation therapist to deliver the treatment on subsequent days. Remember that patients may require more than one session for simulation. Simulation is very important, since it is the step that allows for proper planning and delivery of the actual treatment. After simulation, there is a lot of behind-the-scenes work. here the medical physicist and dosimeterist are involved. CT scans may have to be taken in order that the computers can calculate and prescribe the dose distribution of the radiation.

Blocks and shields are often fashioned for the patient undergoing radiation treatment. Blocks or shields are pieces of lead that are placed on a tray between the patient and the treatment machine. The blocks basically will cover up normal tissues in the body in order that radiation is delivered principally to the tumor. External radiation is a safe and basically painless form of treatment.

Treatment:

Usually, the treatment course lasts between two and five weeks. Patients are brought by the radiation therapist into the treatment room and positioned onto the treatment table. the treatment will then be set up by the radiation therapist, and the actual treatment itself will only last a couple of minutes. During the actual treatment, patients are alone in the room but the radiation therapist is outside and can hear patients through a close circuit television.

The treatment is painless. Patients do not hear or feel anything during or after the treatment. Patients will then return on schedule to complete the treatment course. During the radiation course, patients are monitored by the radiation oncologist and his/her staff. These are called status checks.

Patients should inform the radiation oncologist of any new symptoms. The side effects of the radiation depend on the exact type of tumor treated and the location of the radiation treatment. During the course of treatment, patients will undergo blood tests -- sometimes once a week -- and they will also have port films performed. These are x-ray pictures taken on the treatment machine which are used to ascertain the accuracy of the treatment plan.

Radiation works best when it is given in small doses over several sessions. In this way, it can kill the tumor cells and yet allow sufficient time for the normal healthy cells around the tumor to repair any damage from the radiation.

Brachytherapy:

Brachytherapy is radiation at short distances. The source of radiation is made in the form of wires, seeds or plaques and are inserted into the tumor for delivering high doses of radiation. These radioactive sources are Cesium, Iridium and Iodine. This type of treatment is very effective in certain types of cancer, such as cancer of the cervix, certain forms of head and neck cancer, and lung cancer.

Intra-cavity radiation. Here the radioactive sources are placed in a holder and inserted into the body organ, such as the uterus, or into the vagina.
Interstitial therapy. Here rods, ribbons, or wires are directly inserted into the soft tissues of the body and placed right into the tumor.

With these two types of treatment, patients would most likely be admitted to the hospital and have the procedure done during an operation and under anesthesia. Patients would most likely remain in the hospital for several days while the radiation source is in place. In a few instances, the source will be left permanently inside the body. However, in the majority of cases, the radioactive sources will be removed after a few days. Patients will have restrictions in the number of people visiting and the time of visitation.

High dose rate brachytherapy. This is another form of radiation therapy that has become very popular in recent years. This is an outpatient form of radiation treatment. The high dose rate machine contains a very high activity radiation source and the source is then delivered through a catheter into a particular organ that is harboring the cancer. Usually the treatment itself lasts only a few minutes. Thereafter, the source is removed and stored within the machine, and the patients go home. Patients may require several sessions of high-dose rate brachytherapy in order to derive the most benefit. Many patients will experience side effects from radiation.

Side effects:

Please remember that the extent and the exact type of side effects are determined by the location of the tumor and the location of the radiation being delivered. Patients should check with their radiation oncologists in advance so that they are warned of any of these potential side effects.

For instance, patients who are undergoing breast irradiation will typically experience a redness, dryness or itchiness of the breasts that usually begins two to three weeks after the treatment is commenced. It will then continue, but will eventually leave several weeks after the radiation treatment course is completed.

Another example of a side effect is diarrhea, nausea or vomiting. This is sometimes experienced by patients undergoing radiation treatment to their abdomens or bowels. In most cases, these side effects, which are called acute, take place during the radiation treatment course and will continue for a few weeks after the course is completed.

In almost all cases, these side effects will go away and patients will be fine. In rare instances, some patients will experience long-term side effects or complications, because the radiation causes damage to an internal organ adjacent to or near the tumor site.

Can radiation can cause cancer?

Radiation can sometimes play a role in the development of cancer, particularly if people are exposed to it at an early age. We are all aware of the increased frequency of cancers, especially Leukemias, among Japanese survivors of World War II. Patients should bear in mind that radiation, as delivered in a radiation department, is a very careful, precise and well monitored treatment which very rarely leads to the development of cancer.

3-D (3- dimensional) Radiation

Patients may also benefit from newer 3-dimensional) treatment planning which involves the use of sophisticated software and computers in designing the various treatment beams and using various treatment blocks in order to precisely localize and focus the radiation to the tumor.

Radio-surgery is a very specialized treatment used for the treatment of various brain tumors and malformations. This is performed with linear accelerators. With radio-surgery, many different fields of radiation are focused on a very small point in the brain,

The effect of radiation can sometimes be enhanced by using radio sensitizer. These are chemicals that can be given during the treatment course. Some commonly used chemotherapy drugs such as Cisplatinum and Carboplatinum are among radio sensitizers.

Intraoperative radiation is another type of radiation where the patient, while undergoing a surgery, is put under a linear accelerator and a fine beam is being concentrated on the tumor bed.

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