Cancer Care 8 min read • January 15, 2026
Proton Beam Radiation vs. Conventional Photons: When is Proton Therapy Indicated?
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Dr. Aravind Subramaniam, MD
Consultant - Radiation Oncology & Proton Therapy
The Physics of the Bragg Peak
Conventional radiotherapy uses X-ray photons that deposit energy along their entire trajectory through the body, delivering exit doses to healthy tissue behind the tumor. Proton therapy uses positively charged heavy particles that deposit their maximum destructive dose precisely within the tumor bed—known as the Bragg Peak—with virtually zero exit radiation.
Crucial Clinical Indications:
- Pediatric Cancers: Sparing developing brain, spinal, and heart tissues prevents secondary malignancies and growth impairments in children.
- Skull Base & Brain Tumors: Proximity to the optic chiasm, brainstem, and auditory nerves makes pencil-beam proton accuracy essential.
- Recurrent Cancers: Patients who have previously received maximum safe doses of conventional radiation can frequently be treated with proton beam therapy safely.