What is Radiation Treatment?

What happens before treatment?

Once a diagnosis has been made, your doctor will discuss all treatment options and may recommend a consultation with a radiation oncologist. The radiation oncologist will perform a physical exam and reconfirm your diagnosis based on the results of imaging studies (x-rays, MRIs) and pathology reports. They will discuss with you the best type of radiation treatment for your particular tumor or lesion, explain the treatment process, and describe some possible side effects. Once you’ve decided to go ahead with treatment, you will sign consent forms.

The first step, called a CT simulation, is performed to carefully plan your radiation treatment. It is a planning procedure, without the actual radiation beam, to determine the type of treatment field, energy source, and angles of the radiation beam. You are positioned on the treatment table and x-rays are taken. An immobilization device may be fabricated and used for the simulation to help you hold still. Information about the tumor location, its volume, and closeness to critical structures is gathered and will be transferred into the treatment planning computer system. Marks may be made on your skin to help the radiation therapist position you for treatment; do not wash them off.

Molds and Masks
Immobilization devices such as molds and masks may be used to hold the treated area perfectly still during radiation treatment. They are custom-made to fit your body area exactly and are used during each radiotherapy visit. These immobilization devices are made from several different materials.

Masks are usually used for the face and neck. A plastic mesh is dipped into a water bath, making the mesh very flexible. The mesh is placed over the body area and allowed to conform (you can still breathe). The mesh dries quickly. A clear plastic shell is made from the mesh mold. If you have a beard or mustache, you may be asked to shave. Molds are usually used for the pelvis, belly and chest.

Determining the treatment plan
High-end computers and special software are used to plan the treatment so that all beams meet – and produce a high, focused dose of radiation – at a central point within the target. The software uses your CT or MRI images to form a 3D view of your anatomy and the target. The team (radiation oncologist and physicist) determines the radiation prescription: i.e. radiation dose and number of treatment beams  It is crucial that the dose is applied only to the target area. By using numerous beams, the radiation dose to normal tissue is minimized. All beams meet at a single point, where the target is located. At the center, the beams add up to a very high dose of radiation.

What happens during treatment?
The treatment takes about 10-30 minutes.

  1. Preparation: The nurse or radiation therapist will escort you to a changing room, where you may need to change into a gown, depending on the area being treated.
  2. Positioning: You will lie on the treatment table and be placed in the exact position as the simulation, using the same mask or mold. Alignment lasers help the radiation therapist position you correctly. Approximately once a week an x-ray, called a port film, or a cone beam CT may be taken of you in your treatment position. The radiation oncologist compares the port film taken during treatment to the x-rays taken during simulation to check the treatment accuracy.
  3. Treatment: Once positioning is confirmed, the therapist leaves the room and operates the machine from the control room. The therapist can watch you through video monitors and speak to you over an intercom. The gantry and treatment table may rotate to deliver radiation beams from one or more directions.

The LINAC machine is large and makes noises as it moves around your body. Its size and motion may be intimidating at first; it may pass close to your body but will not touch you.

  1. Weekly check-up: The radiation oncologist will meet with you once a week for a treatment management visit. He will examine you, discuss any side effects you may be experiencing, determine how well you are responding to the treatment and answer any questions

What happens after treatment?
After your treatment the radiation therapist will remove any body molds or masks and allow you to go back to the changing room. Once you’ve gathered your belongings, you may leave.

What are the results?
Several months after treatment, CT, MRI or angiography scans will be taken to look for signs of response. Several months may pass before the effects of treatment are visible. Doctors will look for signs of tumor shrinkage or slowing of further tumor growth. Results of radiotherapy vary depending on the size, location and type of tumor. Talk to your doctor about your specific prognosis.

What are the side effects?
Side effects vary depending on the tumor type, total radiation dose, size of the fractions, duration of therapy, and amount of healthy tissue in the target area. Some side effects are temporary and some are permanent. Generally, patients may experience fatigue, skin irritation around the target area, and hair loss.

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