Proton therapy (proton beam therapy) uses proton beams to deliver radiation directly to a tumor. It can precisely deliver high levels of radiation to the tumor to kill cancer cells while preserving the surrounding healthy tissue.

Most types of health insurance in the United States, including Medicare, typically cover proton therapy.

Glossary of Medicare terms

  • Out-of-pocket cost: This is the amount a person must pay for care when Medicare does not pay the total amount or offer coverage. Costs can include deductibles, coinsurance, copayments, and premiums.
  • Premium: This is the amount of money someone pays each month for Medicare coverage.
  • Deductible: This is an annual amount a person must spend out of pocket within a certain period before Medicare starts to fund their treatments.
  • Coinsurance: This is the percentage of treatment costs that a person must self-fund. For Medicare Part B, coinsurance is 20%.
  • Copayment: This is a fixed dollar amount a person with insurance pays when receiving certain treatments. For Medicare, this usually applies to prescription drugs.

Medicare will typically cover proton therapy. Healthcare experts generally consider the technique a reasonable treatment when sparing the surrounding tissue is not possible with traditional photon-based radiation therapy and when this approach would benefit the individual.

For example, Medicare will typically cover proton therapy in the following situations:

  • Specific treatment doses are necessary to avoid an excessive dose “hotspot.”
  • The same area or an immediately adjacent area has previously undergone radiation treatment.
  • The target area is close to one or more critical structures.

Medicare Part A covers proton therapy that a person receives while admitted to the hospital. If an individual undergoes this therapy on an outpatient basis or in a freestanding clinic, Part B covers the treatment.

Learn about the parts of Medicare.

If proton therapy is part of a person’s treatment while they are admitted to the hospital, Medicare Part A covers it. However, they are responsible for the Part A coinsurance and deductible. In 2025, the deductible is $1,676 for each hospital stay.

Once an individual reaches the deductible, they will pay $0 for up to 60 days. After 60 days, a person pays the following coinsurance amount:

  • Days 61 to 90: $419 per day
  • Days 91 to 150: $838 per day while using lifetime reserve days
  • Day 151 and beyond: the entire cost

Lifetime reserve days are additional days that Medicare pays for if a person is in the hospital for more than 90 days. Individuals have 60 reserve days for their lifetime.

If Part B covers proton therapy because a person undergoes the treatment on an outpatient basis, the individual is responsible for the monthly premium, deductible, and coinsurance.

In 2025, the Part B standard premium is $185 per month, while the deductible is $257. Once an individual reaches the deductible, they are generally responsible for 20% of the Medicare-approved cost.

Learn more about Medicare costs.

Medicare resources

For more resources to help guide you through the complex world of medical insurance, visit our Medicare hub.