Would you offer re-irradiation LDRT for someone with osteoarthritis or tendinitis if symptoms recur?

I have not personally offered a patient a third round of LDRT and do not know of any data that shows efficacy. However, I might offer a third round if a particular patient got adequate results with the first two and there was some separation in time (perhaps >1 year) since the last round.

Yes, this is commonly practiced and supported by large series showing additional responders with a second course and very low toxicity; I usually wait 12-16 weeks after the first course to allow full biological effect and to be sure the recurrence is durable. (Rühle et al., PMID 34342662). Dr. Seege...