This seems like sbrt on steroids
They say nothing about prostate cancer but they do mention painful bone tumors.
FLASH radiotherapy cancer treatment aces first human trial
Https://freethink.com/health/flash-...
It delivers a dose of radiation that’s over 300 times higher than traditional radiation therapy in just a fraction of a second. This induces something called the “FLASH effect” — a not-entirely-understood phenomenon in which the radiation still attacks the tumor, but doesn’t harm surrounding tissue.