What is Proton Beam Therapy?
Proton Beam Therapy, is a painless, noninvasive, precise form of radiation therapy used to treat cancer and other benign conditions.  Proton beam therapy has been used to treat more than 45,000 patients since 1954. Most of those patients were treated in research facilities, however, since 1993, the Optivus system has safely treated nearly 13,000 patients in a clinical setting.

How Does Proton Therapy Work?
Protons are stable, positively charged subatomic particles with a mass 1800 times that of an electron. These characteristics allow the proton's dose of radiation to be controlled to an exact shape and depth within the body.  The proton's penetration through tissue is a function of the proton beam's energy and the tissue density through which it passes. Selecting the beam's energy controls the penetration Protons slow down as they interact with matter. When their velocity slows down enough, they release the bulk of their energy in a sharp burst (ionization), followed by a rapid decline in their dose energy. Virtually no radiation is expended beyond this point. This is the Bragg Peak.

The Bragg Peak is representative of a delivery of a full, localized, and uniform dose of energy in the tumor. As a consequence, very little radiation is deposited on peripheral tissue. The ability to target tumors precisely and in three dimensions is what makes Proton Therapy superior to other treatment options. As a result, Proton Therapy is ideal for tumors in or near critical structures (such as the brain, heart, optic nerve or spinal cord) that cannot tolerate much radiation and are inoperable.

 X-Ray Radiation Therapy can control many forms of cancer, however, most of the radiation is deposited  on healthy tissue. Since X-rays can only be controlled in two dimensions, healthy tissue beyond the cancer (exit dose) receives high-doses of radiation as well.

Proton Beam Therapy, unlike x-ray therapy, can be three-dimensionally conformed to the cancer's shape. It deposits the majority of it's energy at the tumor itself and spares healthy surrounding tissue.

Consequently, tissues in front of the target (entrance dose) receive a very small dose, tissues adjacent to the tumor receive virtually no none.

Conditions Treated With Proton Therapy
Listed below is an abbreviated list of clinical sites of proton therapy. For a more comprehensive list and definitions, please click here to navigate to Loma Linda University Medical Center's website.
 

• Acoustic Neuroma
  
• Arteriovenous malformations (AVMs)
  
• Brain tumors in children
  
• Chordomas and chondrosarcomas
• Isolated brain metastases
  
• Macular degeneration
  
• Meningiomas
  
• Carcinoma of the nasopharynx
  
• Orbital and ocular tumors in children
  
• Locally advanced oropharynx cancer
  
• Pituitary adenomas
  
• Prostate cancer
  
• Sarcomas of the base of skull and spine in children
  
• Non-small-cell lung cancer (medically inoperable)
  
• Uveal melanomas