Proton therapy is an advanced radiation treatment that uses a precisely controlled proton beam to destroy cancer cells while reducing radiation to nearby healthy tissue. Conventional X-ray treatment spreads radiation energy along its entire path, through the tumor and into healthy tissue beyond it. But with proton therapy, doctors calibrate the beam to release most of its energy within the tumor itself. After treating the target, the radiation rapidly stops. This article explains how proton therapy works, what to expect during treatment, and which patients may benefit from it.
The Science Behind Proton Therapy
To understand how proton beam therapy works, let’s imagine following a single proton into the body. At its initial contact with human tissue, the proton deposits a low dose of radiation. Once it reaches the target site, it releases the bulk of its energy in a burst known as “the Bragg peak,” a defining feature of proton therapy.
By adjusting the proton beam’s energy level, the oncology team shapes the Bragg peak to match the target’s size, shape, and depth. Beyond the Bragg peak, radiation levels drop off sharply, avoiding exit dose radiation to the tissue beyond the target.
Pencil Beam Scanning
The most advanced method of delivering proton therapy is “pencil beam scanning,” which Emory Proton Therapy Center uses in all of its treatment rooms. In pencil beam scanning, a narrow proton beam is steered spot-by-spot and layer-by-layer to cover the entire target. Tumors grow in irregular shapes, but the beam works like an artist’s brush, tracing the tumor’s contours with precision. The radiation intensity can be adjusted at each spot to create a highly precise treatment that reduces radiation dose to nearby tissues and organs.
What to Expect: The Treatment Process
At Emory Proton Therapy Center, proton therapy follows a step-by-step path from first visit to final session:
Step 1: Consultation and evaluation
A radiation oncologist reviews your diagnosis, imaging, and history to make sure that proton therapy is right for you.
Step 2: Simulation and imaging
The team conducts a CT or MRI scan in the planned treatment position. Custom supports are made to help you hold that position during each session.
Step 3: Treatment planning
Physicists and dosimetrists put together a detailed plan for your treatment, determining the beam angles, energy levels, and dose distribution.
Step 4: Delivery
The average treatment visit lasts 30-60 minutes. Most of that time is spent in setup. The actual proton treatment delivery time is typically just a few minutes. Most patients come five days a week over several weeks. During consultation, your physician will discuss the recommended number of treatments.
Conditions Proton Therapy Can Treat
Proton radiation therapy treats a wide range of cancers and tumors. It’s especially well-suited for tumors near sensitive organs like the brain, spinal cord, heart, and bowels, and for children and others who are especially sensitive to radiation.
Doctors commonly use proton therapy to treat:
- Brain and spine tumors
- Head and neck cancers
- Lung cancer
- Breast cancer
- Gastrointestinal cancers
- Prostate cancer
- Pediatric cancers
- Recurrent cancers in areas that previously received radiation
Benefits and Side Effects
Because proton therapy limits the dose that reaches surrounding tissue, patients may experience fewer and milder side effects than with X-ray radiation. Side effects from any type of radiation depend on the area being treated and may include fatigue and temporary skin irritation near the treatment site. Before you begin treatment, your care team will discuss what to expect for your specific radiation treatment plan, and what advantages proton therapy may offer over other types of treatment.
Is Proton Therapy Right for You?
Developing a comprehensive treatment plan can be complex. The right treatments depend on the type of tumor or cancer that you are facing, where it’s located, and the treatment goals. At Emory Proton Therapy Center, your care is coordinated by specialists from Winship Cancer Institute of Emory University, Georgia’s only National Cancer Institute-designated Comprehensive Cancer Center. Our expert physicians review your case and discuss proton therapy alongside other treatment options. Schedule a consultation with us to learn what benefits proton therapy could offer for your care.