Radiation Therapy Oncology Group (RTOG) Validated Regimens.
Prescription Protocol
< 2 cm
24 Gy
Prescribed to 50% isodose line.
2.1 - 3.0 cm
18 Gy
Prescribed to 50% isodose line.
3.1 - 4.0 cm
15 Gy
Prescribed to 50% isodose line.
> 4.0 cm
FSRT
Consider fractionation or surgery.
Clinical Warning
Final prescription depends on distance to critical structures (OARs) and prior radiation history.
Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
Treatment planning for single-fraction stereotactic radiosurgery (Gamma Knife / CyberKnife).
Selecting marginal doses based on tumor histology and volume constraints.
Section 2
Literature
Development
Lars Leksell pioneered stereotactic radiosurgery in 1951. The modern standard dosing regimens for brain metastases were primarily defined by the landmark RTOG 90-05 trial, which established the maximum tolerated doses based on lesion size.
Section 3
Pearls/Pitfalls
Optic Apparatus
Regardless of the target pathology, the absolute maximum point dose to the optic chiasm or optic nerve must be strictly maintained at < 8 Gy to prevent catastrophic radiation-induced optic neuropathy (blindness).
Section 4
Evidence Appraisal
Primary Reference
Single dose radiosurgical treatment of recurrent previously irradiated primary brain tumors and brain metastases: final report of RTOG protocol 90-05
Shaw E et al. • Int J Radiat Oncol Biol Phys. 2000;47(2):291-8
