Proton therapy

Proton therapy is a technologically advanced, precise treatment that allows radiation to be focused directly on a tumor, with a goal of minimizing radiation to healthy tissue. Research shows that proton therapy can minimize short- and long-term side effects, reduce the occurrence of secondary tumors, and improve a patient’s quality of life.  

There are fewer than 100 proton therapy centers worldwide that offer this state-of-the-art technology, and Seattle Cancer Care Alliance (SCCA) Proton Therapy Center, led by world-class experts in proton therapy, is the only facility of its kind in a seven-state region. 

Telehealth consultations available

At the SCCA Proton Therapy Center, we now offer convenient telehealth appointments for new and existing patients from the state of Washington to discuss treatment options and follow-up care from home. 

During a telehealth consultation, you will meet with your physician via videoconferencing or by phone to discuss your cancer type and treatment options, including proton therapy. If you are an existing SCCA patient, you may also have the option to complete your follow-up appointments during treatment via telehealth.   

When the time comes to visit the Center in person, you can rest assured that we are taking increased precautions to keep both patients and staff safe in light of the COVID-19 virus. 

Learn more on the SCCA Proton Therapy Center website

“It’s a privilege that my job is to help people in their time of need. Work doesn’t feel like work when you know what you’re doing is meaningful.”
— Jing Zeng, MD, Medical Director

Adults and children benefit

Proton radiation therapy can be used to treat a broad range of tumors in adults and children, such as brain, central nervous system, gastrointestinal tract, head and neck, breast, lung and prostate, as well as sarcomas. It can also help patients whose cancers have recurred, and patients who can’t tolerate additional radiation therapy. 

Click one of the buttons below to learn about proton therapy and adult cancers, childhood cancers or information for parents and guardians:

Frequently asked questions (FAQs): Proton therapy and you

Is proton radiation therapy a good approach for all types of cancers?

No. It is most effective when used to treat solid tumors that are well defined and those that have not spread (metastasized) to other parts of the body.  If the tumor has metastasized, proton therapy may still be an option, depending on the extent of the metastasis and other factors.

Can proton therapy be used in combination with other cancer treatments?

In many cases, yes. Cancer treatment frequently involves more than one approach. For example, proton radiation therapy can be used with chemotherapy, in conjunction with surgery, and/or in combination with conventional radiation delivered with X-rays. If your disease can be treated most effectively with a combination of therapies, your physician will discuss this with you. 

Can proton radiation therapy be used to treat recurrent cancers?

In many cases, yes. Proton therapy can be used to treat recurrent cancers that are untreatable by conventional radiation. Patients should discuss proton radiation therapy with their physician (radiation oncologist) to determine if it can be beneficial in their particular case. Proton therapy can also be an option for patients who have already had a course of conventional radiation and are unable to receive more.

SCCA Proton Therapy Center

Located on the UW Medical Center Northwest campus at 1570 N 115th St. Seattle, WA 98133
phone (206) 306-2800
Monday – Friday 8am to 5pm
fax (206) 417-0467

Frequently asked questions (FAQs): What to expect

How long will my treatment last?

Most patients are scheduled to receive therapy five days a week (excluding weekends and holidays) for a period of four to nine weeks, depending on a variety of factors, such as the type of tumor and where it is located.

I live outside the Seattle area and will need a place to stay while I’m being treated. Can you help me?

Yes. Our concierge can tell you about options and help you find housing.

Do I need to get approval in advance from my insurance provider to receive proton therapy?

Yes. While most private insurance plans, Medicare, and in many cases, Medicaid, cover proton therapy, some do not. For this reason, it’s important to get approval in advance before receiving proton therapy.  

We will assign you a Patient Navigator who will help you understand your insurance coverage, as well as estimated costs associated with treatment. If you do not have insurance coverage, your Patient Navigator can assist you in finding alternative ways to cover the costs of your treatment. 

Learn About Costs and Coverage

How long will each treatment session take?

The time spent delivering proton therapy is only a few minutes, but the entire treatment session may take up to 30 minutes. Much of your appointment time will be used to ensure that your positioning is identical to the one created during the CT simulation process. This is achieved by daily imaging, and the use of special immobilization devices such as: masks, leg molds, headrests, sponges and pillows. Many of the devices that are used are customizable and made just for you to ensure that you receive an accurate treatment.  

Learn More

How long will the radiation remain in my body after proton therapy?

Proton radiation has a very short life. Once the protons are delivered, you can leave the treatment room without any risk of radiation exposure to others.

What side effects might I experience?

Typically, there are no or few side effects from proton therapy. If there are side effects during or after treatment, they are generally minor and occur after a number of treatments. Before treatment begins, your physician will discuss with you any side effects that could occur. If you do experience any side effects, your nurse will help you manage them.  

Treatment overview 

At your first in-person appointment, you’ll meet with your radiation oncologist and a nurse to discuss proton therapy, your treatment and any tests you may need before treatment can begin.  

You’ll also meet other members of your care team, such as a radiation therapist and patient navigator/concierge, who will work with you throughout your treatment and follow-up care. This is also a time for us to get to know you and your family and for you to get answers to any remaining questions you may have about proton radiation therapy.  

Simulation and planning 

After your first appointment and you’ve completed any additional tests you may need, we will schedule you for a computed tomography simulation (CT) scan.  This scan will be used by your care team to create a personalized treatment plan for you. The plan will provide important details, including the exact dose of protons your physician will need to precisely target your tumor.  

This scan will take up to two hours, including preparation time. A nurse will also explain the process from CT simulation through the end of treatment and answer any questions you may have.  


Proton therapy typically takes about four to nine weeks. We’ll guide you every step of the way through the treatment process, and make sure you and your family have the information and resources you need.  

When you’ve completed treatment and it’s time to go home, you’ll still be in contact either with us or your referring physician.

Frequently asked questions (FAQs): Proton therapy technology

What technology does SCCA Proton Therapy offer?

The driving force behind proton radiation therapy is a machine called a cyclotron that energizes protons so they can be used in treatment. First, electricity is applied to hydrogen gas, which causes atoms to eject protons. The cyclotron then spins these protons and a magnet guides them via a beam from the cyclotron to the tumor. 

Learn More

How do proton beams destroy cancer cells?

All radiation therapies, including protons and conventional radiation delivered with X-rays, destroy cancer cells by damaging their DNA. When protons reach the nucleus (or center) of cancer cells, they transfer energy to the cells’ electrons causing a series of interactions, or ionizing events, that damage the DNA. Cancer cells whose DNA is damaged beyond repair can no longer divide—and they ultimately die. These cells are then broken down and eliminated by the body’s natural processes.

Why don’t protons do more damage to healthy tissues?

Proton radiation can be precisely calibrated and directed to release most of its energy at the site of the tumor. Thus, higher doses of radiation typically can be delivered more safely with proton therapy as it poses much less exposure to healthy tissue. It’s also helpful to know that proton therapy deposits less radiation in the healthy tissue in front of the tumor compared to conventional radiation delivered with X-rays, and almost none is deposited in the healthy tissue behind the tumor.

Is conventional radiation as effective as protons in destroying tumors?

Conventional radiation and proton radiation can be equally effective in destroying cancer tumors. The difference is that conventional radiation damages more healthy tissue in the process, as its delivery is less precise. Also, conventional radiation releases much of its energy shortly after penetrating the skin. This damages healthy tissue and organs as the x-rays make their way to the tumor and again as they continue through the body beyond the tumor.  

Care team

Your Seattle Cancer Care Alliance (SCCA) proton therapy team is here not only to treat you, but to listen to you and take care of you and your family. They are experts in the field of proton radiation therapy, and focus exclusively on treating patients just like you, every day, and understand your questions, needs and concerns.  

Your team includes a group of world-class professionals including a radiation oncologist, radiation therapist, nurse, physicist and dosimetrist, all here to support you. We integrate supportive care services, such as social workers, child life specialists, registered dietitians and integrative medicine specialists, to promote your well-being in every sense.  


The physician-scientists at Seattle Cancer Care Alliance (SCCA) have been at the forefront of cancer research for decades, in order to help bring patients the best treatment options possible.  

Patients who participate in our clinical studies often have the first chance to benefit from new treatment approaches and contribute to medical science regarding proton therapy.