Proton therapy

Proton therapy is a kind of radiation used to treat cancer. Like other types of radiation, proton therapy kills cancer cells and stops them from growing.

Information

Most types of radiation therapy use x-rays to destroy cancer cells. Proton therapy uses a beam of special particles called protons. Proton beams can be better aimed onto a tumor, so there is less damage to the surrounding healthy tissue. This allows a higher dose of proton therapy to be used than can be used with x-rays.

Proton therapy is used to treat cancers that have not spread. Because it causes less damage to healthy tissue, proton therapy is often used for cancers that are very close to critical parts of the body.

Proton therapy may be used to treat the following types of cancer:

• Brain (acoustic neuroma, childhood brain tumors)

  Acoustic neuroma

  An acoustic neuroma is a slow-growing tumor of the nerve that connects the ear to the brain. This nerve is called the vestibular cochlear nerve. It...

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  Childhood brain tumors

  A brain tumor is a group (mass) of abnormal cells that grow in the brain. This article focuses on primary brain tumors in children.

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• Eye (ocular melanoma, retinoblastoma)

  Ocular melanoma

  Melanoma of the eye is cancer that occurs in various parts of the eye.

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  Retinoblastoma

  Retinoblastoma is a rare eye tumor that usually occurs in children. It is a malignant (cancerous) tumor of the part of the eye called the retina....

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• Head and neck
• Lung
• Spine (chordoma, chondrosarcoma)

  Chondrosarcoma

  A bone tumor is an abnormal growth of cells within a bone. A bone tumor may be cancerous (malignant) or noncancerous (benign).

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• Prostate
• Lymph system cancer

Researchers are also studying whether proton therapy might be used to treat other noncancerous conditions, including macular degeneration.

HOW IT WORKS

A member of the radiation therapy team will fit you with a special device that holds your body still during treatment. The actual device used depends on the location of your cancer. For example, people with head cancers may be fitted for a special mask.

Next, you will have a computed tomography (CT) or magnetic resonance imaging (MRI) scan to map out the exact area to be treated. During the scan, you will wear the device that helps you stay still. The radiation oncologist will use a computer to trace the tumor and outline the angles at which the proton beams will enter your body.

Proton therapy is performed on an outpatient basis. The treatment takes a few minutes a day over a period of 4 to 7 weeks, depending on the type of cancer. Before the treatment begins, you will get into the device that will hold you still. A member of your care team will take a few x-rays to fine-tune the treatment before each daily session.

You will lie down flat on a table that can be placed inside a donut-shaped device called a gantry. It will rotate around you and point the protons in the direction of the tumor. A machine called a synchrotron or cyclotron creates the protons, and using a series of magnets, speeds up the protons to accurately deliver the protons to the tumor.

The technician will leave the room while you are having proton therapy but can see and hear you on the monitors. The treatment should only take 1 to 2 minutes. You should not feel any discomfort. After the treatment is over, the technician will return to the room and help you remove the device that held you still.

SIDE EFFECTS

Proton therapy may have side effects, but these tend to be milder than with x-ray radiation because proton therapy causes less damage to healthy tissues. Side effects depend upon the area being treated, but may include skin redness and temporary hair loss in the radiation area.

AFTER THE PROCEDURE

Following proton therapy, you should be able to resume your normal activities. You will likely see your health care provider every 3 to 4 months for a follow-up exam.