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What is proton therapy?

Proton therapy is a type of radiation therapy, which is among the most commonly used treatments for cancer. Like all radiation therapy, proton therapy uses an intense beam of high-energy particles to destroy cancer cells. While traditional radiation therapy uses photons (x-rays) to do this, proton therapy uses a beam of protons. Proton therapy has been FDA approved for cancer care since 1988.

What is the advantage of using protons for radiation?

Protons are just as effective as photons for destroying cancer cells, but proton particles operate a bit differently. Once a proton beam reaches the tumor it’s targeting, it stops, preventing healthy tissues nearby from receiving radiation.

What types of cancers can be treated with proton therapy?

Proton therapy is well suited for solid tumors located in one part of the body (localized tumors). Treatment is especially helpful for tumors in or near vital organs, cancers that have come back (recurrence), and a variety of pediatric cancers. Find out which cancers are good candidates for proton therapy.

Why isn’t proton therapy available everywhere?

Although proton therapy is not a new technology, it does require sophisticated, specialized equipment. As of 2019, proton therapy is available at fewer than 30 proton therapy centers nationwide. MPTC is the only proton center in the state, and patients travel from around the country and world to be treated by our expert team. Learn why patients are choosing MPTC.

Ready to find out if proton therapy is right for you? Call 410-369-5200 or fill out the form below to schedule your consultation with our expert team.

Proton Therapy Basics

Every cancer diagnosis is different. Therefore, each person fighting the disease requires a different approach for treatment. About 60% of people with cancer will receive a course of radiation as part of their treatment plan, and 30% of these patients could benefit from proton therapy. Unlike traditional radiation that uses photons which penetrate through the body, proton therapy targets solid tumors with pinpoint accuracy and delivers a maximum radiation dose that stops at the tumor site, sparing healthy tissue. 

When determining the appropriate treatment plan, your quality of life is at the forefront of our physicians’ minds. Because healthy tissue is spared with proton therapy, it ultimately results in far fewer side effects, including secondary cancers caused by radiation. This powerful tool in the cancer fighting toolbox helps patients get back to their lives after treatment by preserving quality of life. 

How it Works

  • Protons are positively charged particles in the nucleus of an atom. Protons and photons are similar in that they both destroy cells, but protons have the advantage of depositing little radiation going into the body and stopping at the tumor site.  
  • The Varian ProBeam® Proton Therapy System at MPTC is one of the most advanced systems in the world. It uses a 90-ton cyclotron to accelerate protons to two thirds the speed of light, sending them down a beamline the length of football field and into one of five treatment rooms.  
  • This hidden 3-story tall machine helps move the treatment nozzle up to 360 degrees into the precise position to deliver your treatment. The beam is delivered without sound or pain in a matter of minutes with millimeter precision. 
  • Physicians can direct the proton beam to the exact shape and size of the tumor by ‘painting’ on the dose layer-by-layer, like a 3-D printer with pencil-beam scanning. Its precision provides a broader use of proton therapy for difficult tumors near highly sensitive vital organs such as the spine or brain. 


Proton therapy’s unique properties offer several benefits for patients with cancer.

Proton therapy is precise. Unlike traditional (photon) radiation, protons travel directly to the site of the tumor and stop. They deliver radiation to the tumor but do not continue through the body. As a result, healthy tissues near the tumor do not receive doses of radiation that they don’t need. This benefit is particularly important for tumors located in or near vital organs like the brain, heart, and lungs.

Proton therapy is powerful. Because it can target tumors so precisely, proton therapy lets physicians treat tumors with higher doses of radiation than other therapeutic methods. For certain tumors, such as sarcomas and some brain tumors, higher doses of radiation can improve patient outcomes.

Proton therapy is noninvasive. Delivered as a course of daily outpatient treatments, proton therapy allows patients to carry on with their lives during treatment. Patients generally tolerate the treatment well and suffer fewer side effects.

Proton therapy is customized. Proton therapy takes advantage of cutting-edge delivery techniques, including pencil-beam scanning and intensity-modulated proton therapy (IMPT), to deliver the right dose exactly where it is needed. IMPT “paints” radiation on layer by layer, hugging the tumor’s shape and minimizing the radiation dose neighboring healthy tissues receive.

Proton therapy gives you options. Proton therapy is safe to deliver before or after surgery, and it can also be combined with chemotherapy. You and your doctor can design the best treatment plan for fighting your unique tumor, and proton therapy can fit in.

Ready to find out if proton therapy is right for you? Call 410-369-5200 or fill out the form below to schedule your consultation with our expert team.

If you or a loved one has been diagnosed with cancerous or non-cancerous tumor, proton therapy may be an option. Review our list of cancers proton therapy may be able to treat.


Proton Therapy Basics

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Request a Consultation

Our team at the Maryland Proton Treatment Center is dedicated to helping you navigate your journey through treatment. After a cancer diagnosis, you may understandably have a lot of questions and we’re here to answer all of them.

To see if proton therapy is right for you, request a consultation by completing the form below. It should only take about 3 minutes to complete.

Once you complete the form, you will receive a call within two business days from our front desk (410-442-6486).