Proton Beam Therapy
Proton beam therapy is a form of radiation that uses charged particles called protons, which release most of their energy at the tumour and then stop. Why does that matter, and who actually benefits? This page explains how it works, who it suits, what it costs in general terms, and how Dr. Karan helps you judge whether protons are worth it in your case.
Reviewed by Dr. P. Vijay Karan Reddy · Radiation Oncologist ·
Last updated October 2026
Proton beam therapy is radiation that uses protons instead of X-rays. Protons release most of their energy at the tumour and then stop, so less dose reaches healthy tissue beyond it. That matters most for children and tumours near critical structures. It can be used for most cancers treated with radiation, but it usually costs more than standard photon radiation.
What Is Proton Beam Therapy? Radiation That Stops at the Tumour
Standard radiation uses photons, which are X-rays. They pass through the body and keep depositing dose on the way out. Protons behave differently: they enter, release most of their energy where the tumour sits, and stop. Doctors call this the Bragg peak, and it's why protons can spare tissue behind the target.
Is it a different treatment, or just a different beam? Mostly the beam. Proton beam radiation therapy still needs planning scans, immobilisation and daily checks. The honest caveat comes from Mayo Clinic: few studies have compared long-term results of protons and X-rays, so the likely gain is fewer side effects in some cancers. Whether protons help people live longer isn't yet clear.
How Proton Beam Radiation Therapy Works
Planning often takes longer than with photons, but each session is quick. Here's what happens before and during treatment.
Proton Beam Therapy by Cancer Type: Who Benefits Most
Protons suit almost any radiation case. These four are where Dr. Karan most often considers them.
Key Benefits of Proton Beam Therapy
These are possibilities, not promises. Benefits vary by case, and cost is the main barrier to proton beam therapy in India.
Proton Beam Therapy vs. Photon Radiation: Differences and Cost
Protons and photons are both radiation, and neither is simply better. Here's how proton therapy compares with the techniques you're most likely to be offered instead.
Proton beam therapy vs. photon radiation (IMRT)
IMRT shapes photon beams to fit the tumour, but photons keep travelling past it, while protons stop. The trade-off is proton beam therapy cost: Johns Hopkins Medicine explains that the machines are expensive to build and operate, so treatment usually costs more.
Proton beam therapy vs. SBRT and SRS
SRS and SBRT use photons to deliver high doses in one to a few sessions. Protons usually take more sessions but can lower the spread of low-dose radiation farther from the target. For small benign brain tumours, Dr. Karan uses SRS.
Preparing for Proton Therapy
Proton planning is detailed because the beam stops at a set depth. Here are four things to expect and ask about.
Proton Beam Therapy Delivery Methods Explained
Machines differ in how they shape the beam. The system at Apollo Chennai, where Dr. Karan's patients are treated for now, is the IBA Proteus ONE, which delivers IMPT.
What a Treatment Day Looks Like
- 01
Check-in
You arrive at the treatment centre, and therapists check your details and preparation. For now that's Apollo Hospital in Chennai, where your treatment runs under Dr. Karan's guidance. Apollo's Jubilee Hills centre in Hyderabad is due to start in October 2027, and Dr. Karan will treat patients there himself.
- 02
Positioning
You lie on the couch while therapists fit your mask or mould. Plan on 15 to 30 minutes of setup before the beam turns on.
- 03
Imaging
An X-ray or CT confirms your position matches the plan. Therapists leave the room but watch you on camera and talk with you over an intercom.
- 04
Beam delivery
The open gantry rotates around you, nothing like an MRI tunnel. You'll hear clicks but feel nothing, and the beam runs for only minutes.
- 05
Finishing up
You go home and carry on with your day, and you're not radioactive. Courses usually run on weekdays, with the same number of sessions as on a linear accelerator for every tumour type.
Proton Beam Therapy Side Effects and Recovery
Do fewer stray rays mean no side effects? Not quite. Protons still release some energy in healthy tissue, so side effects can still occur.
Short-Term Effects
Fatigue, dry or sunburn-like skin, and soreness or hair loss in the treated area are common. They build over the weeks and usually settle with rest, gentle skin care and medicines.
Long-Term Effects
Late effects depend on the area treated and the dose. Protons aim to lower them by sparing nearby tissue, and regular follow-up catches changes early, when they're easiest to manage.
Recovery Between Sessions
Most people go home and resume normal activities. Rest and good food help. Young children may need sedation or anaesthesia to stay still, so they stay a little longer afterwards.
Considering Protons? Get a Second Opinion First
Been told protons might help, or wondering whether you should be asking for them? Send your scans and reports. Dr. Karan will tell you honestly whether protons would make a real difference in your case, and what that route would involve. He brings eleven years in radiation oncology to every review.
What Happens After Treatment
Protons keep working on the tumour for weeks after your final session. Here's the general roadmap, not a personal schedule.
Timing depends on the cancer treated, your plan and your recovery. If you travelled to a proton centre, follow-up can often continue closer to home.
Questions Patients Ask Us
No. You won't feel the beam, and any discomfort comes from lying still in your mask or mould.
Dr. Karan says it can be used in essentially all indications where radiation is used. The practical gain is greatest in children and tumours near critical structures.
It usually costs more than standard radiation, and the final figure depends on the cancer, the number of sessions and the centre. At Apollo Chennai it currently runs ₹25 to 35 lakh, depending on the number of sessions. In Hyderabad it's expected to be ₹20 lakh or less. Photon radiation costs ₹2.5 to 4.5 lakh, so protons cost around ten times as much for now. Dr. Karan weighs cost against benefit in each case and advises accordingly.
Yes, but only at a few centres, in cities such as Chennai and Mumbai. Dr. Karan's patients are treated at Apollo Chennai for now, under his guidance. He'll treat patients himself at Apollo's Jubilee Hills centre in Hyderabad once it opens in October 2027.
Dr. Karan says the number of sessions is the same as on a linear accelerator, for all tumours. Courses usually run on weekdays.
Expect 15 to 30 minutes of setup, while the beam itself runs only a few minutes, according to Mayo Clinic. Allow longer for the whole visit.
Yes, and it's often the preferred option: Dr. Karan recommends protons for children whenever possible, mainly for brain and spinal tumours, because growing bodies are more sensitive to radiation. Young children may need sedation or anaesthesia to stay still.
Not for everyone. It's more precise, which helps when the heart and lung sit close to the treatment area, but standard radiation treats most breast cancers well, and protons cost more.
Some insurers cover it, up to a limit. Coverage varies by insurer and policy, so ask yours for written pre-authorisation before treatment starts.
Yes, it's available. Dr. Karan says protons would be the preferable technique, but he doesn't usually use or suggest them for it, because the benefit is low for the cost. Most transplant centres use photon radiation, and he'll go through the options with you and your transplant team.
Get a Clear Answer on Whether Protons Are Worth It for You
Send your scans and reports, and Dr. Karan will explain whether proton beam therapy fits your case, what the cost means in practical terms, and what comes next. No hard sell.
Written & reviewed by Dr. P. Vijay Karan Reddy ·
Radiation Oncologist · Last reviewed October 2026