How Proton Therapy Works

Proton therapy isn’t a new medical procedure, but it’s still one that’s relatively obscure. With the first proton accelerator solely devoted to medical use in 1990, this revolutionary type of radiation therapy has been used to treat tens of thousands of cancer patients in the United States since in the past two decades.  

Proton therapy administers streams of protons as therapy for certain cancers like prostate cancer, meningiomas and chondrosarcoma, at the site of the cancerous growth. This innovative and physics-based therapy leaves healthy tissue undamaged, unlike other types of radiation therapy treatments that damage tangential tissue and vital organs along with the cancerous growths.

How Does Proton Therapy Works?
Proton therapy is rooted in physics with the use of protons, which are subatomic particles, rather than x-rays to destroy the tumor (tumour). When x-rays are used as radiation therapy for cancer patients, they are aimed at a patient's tumor (tumour); and since they have no charge, they distribute energy evenly, at a decreasing rate over a large surface area. That means that the x-rays target the cancerous site, but also affect the surrounding healthy tissue, albeit at a smaller and less intensified rate. Protons target the surrounding tissue and organs at a rate of 60% lower than traditional x-ray radiation therapy.

However, with proton beams, the proton delivers its charge to a defined depth, which isolates the tumor and minimizes the potential damage to surrounding tissue and organs. Along with the benefit of sparing the surrounding tissue and organs, the impact upon the tumor itself is much greater and more concentrated, making it more effective and decreasing the likelihood of the recurrence of cancer in surrounding tissue later.

How Is The Proton Beam Created?
Proton beams are generated inside of a machine called a synchrotron or a cyclotron. The acceleration of the protons reveals their intense and powerful energy and, depending on the amount of energy in the protons, they penetrate to a certain depth in the body and deposit the specified dose of radiation to the cancerous site, leaving a nominal amount of radiation behind in its wake.

The tumor is pinpointed before the proton therapy session by using computed tomography (CT) or magnetic resonance imaging (MRI).

Which Cancers Can Be Treated With Proton Therapy?
Since proton therapy is so precise, it is best used to treat cancers that have not yet spread throughout the body. It is particularly useful in treating children’s cancers in order to avoid damaging healthy, growing tissue. Proton beam therapy is highly effective in treating the central nervous system in the brain and spinal cord including chondrosarcoma and meningiomas, as well as eye cancers like retinoblastoma and orbital rhabdomyosarcoma. Additional cancers that are handled effectively with proton therapy are prostate, liver, lung, as well as pelvic and spinal sarcomas.

This type of treatment uses expensive and highly specialized equipment; therefore, it is a more challenging treatment for patients to obtain since it is only available at a handful of treatment centers in the United States. But as patients and medical professionals learn more about proton therapy, making it a more accessible treatment may become a priority.