Proton Therapy

Proton therapy is a type of radiation therapy that uses protons to treat cancer.

What makes proton therapy different is how the beam releases its energy. X-ray beams pass all the way through the body, delivering radiation both before and after the tumor. Proton beams release most of their energy at a specific depth (called the Bragg peak) and then stop.

This allows doctors to:

• Deliver a precise dose to the tumor
• Reduce radiation to healthy tissues and organs
• Lower the risk of certain short- and long-term side effects

[Consultation]

• Consult with a radiation oncologist to review your medical history, imaging, and treatment goals. Please bring any previous image scans, pathology reports, and a list of your current medications.

[Simulation]

Before treatment, you should do a simulation. 

• You will be positioned the same way you will lie during each treatment.
• A custom immobilization device may be made to help you stay still. This can be a mask, a body mold, or a cushion.
• A CT scan will be taken. MRI or PET scans may also be used to define the treatment area precisely.
• Small skin marks or tattoos may be placed to help align you accurately each day.

[Treatment Planning]

• After simulation, your care team of physicians, medical physicists, and dosimetrists will design a treatment plan tailored to you. This usually takes one week.

[Treatment schedule]

• Proton therapy is usually given once a day, five days a week, for one to eight weeks. The number of sessions depends on your diagnosis and treatment plan.

[During each session]

• You will change into a gown if needed and be positioned on the treatment table using your immobilization device.
• The team will take X-ray or CT images to confirm your position. This step often takes the most time.
• The beam itself is delivered in only a few minutes. You will be alone in the room, but the team watches you on camera and can talk with you by intercom at all times.
• Most sessions take 15 to 45 minutes in total.

[Weekly check-ups]

• You will meet with your radiation oncologist at least once a week during treatment to review how you are feeling and manage any side effects.

[Common general side effects]

• Fatigue: Tiredness is common during treatment.
• Skin changes: The skin in the treatment area may become red, dry, itchy, or darkened, similar to a sunburn. 

[Side effects specific to the treatment area]

• Head and neck: mouth sores, dry mouth, changes in taste, sore throat, difficulty swallowing
• Brain: headache, hair loss, nausea
• Chest: cough, painful swallowing, shortness of breath
• Abdomen and pelvis: nausea, diarrhea, frequent urination, changes in bowel habits
• Breast: skin irritation, breast swelling or firmness

[How results are measured]

• Radiation continues to work for weeks to months after your last session, so the effect of treatment could not be seen right away. Your care team will use physical exams, blood tests, and imaging (such as CT, MRI, or PET) to evaluate how the tumor has responded.

[Long-term care]

• Keep all follow-up appointments, even if you feel well. Regular check-ups allow your team to monitor for recurrence and to detect and manage any late effects early.