Hypofractionation

Definition: Hypofractionation refers to a radiotherapy regimen in which fewer but larger doses (fractions) of radiation are delivered compared to conventional schedules. The total dose may be similar or slightly lower, but the treatment is completed in fewer sessions.

Tumors with a low α/β ratio (e.g., prostate cancer, some slow-growing brain tumors like meningiomas) are more sensitive to higher doses per fraction and may benefit from hypofractionated regimens.

⬇️ Low α/β → Better suited for hypofractionation
⬆️ High α/β → Prefer conventional fractionation

• Precise image guidance (IGRT)
• Accurate immobilization
• Advanced treatment planning systems
• Often uses IMRT or SBRT platforms

• Meningiomas (especially skull base)
• Brain metastases (as alternative to single-fraction radiosurgery)
• Chordomas and spinal lesions
• Selected cases of gliomas and post-op irradiation

Hypofractionation offers outpatient treatment, reduced patient burden, and potential cost savings — when properly indicated.

• Risk of late toxicity in surrounding critical structures (optic pathways, brainstem)
• Not suitable for rapidly proliferating tumors
• Requires high infrastructure and QA standards

• ultra_hypofractionation
• stereotactic_body_radiotherapy
• alpha_beta_ratio
• radiobiology
• fractionation_schedule