Standard fractionation

  • 1.8–2.0 Gy per fraction, once daily, 5 days/week.

  • Designed to spare late-responding tissues (low α/β).

Hyperfractionation

  • Definition: smaller fractions (≈1.1–1.2 Gy) given more than once per day.

  • Goal: spare late-responding normal tissues while escalating total dose.

  • Example: CHART (Continuous Hyperfractionated Accelerated RT).

Accelerated fractionation

  • Definition: shorten overall treatment time by giving more fractions per week or multiple fractions/day.

  • Goal: limit repopulation in rapidly dividing tumors (e.g., head & neck cancer).

Clinical relevance

  • Improves locoregional control in H&N cancers, but may increase acute toxicity.

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