What brainstem constraints do you use when giving single fraction SRS for trigeminal neuralgia vs brain metastases?

Dose prescription for brain metastases is dependent on volume, location, and prior radiation exposure. With lesions in the brain stem we decrease the dose compared to the standard doses we deliver. For small volume lesions (< 1 cm³) we generally use margin doses of 20 Gy, with lower doses for larger...