IMRT — Intensity-Modulated Radiotherapy.

IMRT is the workhorse of modern radiation oncology — the technique that lets a dose be shaped to a tumour's actual three-dimensional outline, not just a box around it.

What it is

Conventional radiation delivers uniform beams. IMRT divides each beam into hundreds of small segments whose intensity is modulated independently, so the combined dose conforms closely to the target while sculpting steep fall-offs around nearby critical structures.

Where it helps most

• Head & neck cancers, where targets sit among delicate structures
• Prostate, breast and many other sites
• Any situation where sparing an adjacent organ matters

What to expect

IMRT is planned from a CT simulation and delivered as painless daily sessions. It is almost always combined with image guidance (IGRT) to ensure the precision the plan assumes.