Is the instruction specified in 10 CFR §35.610(d) required for users of teletherapy units for non-medical purposes?
Yes, but only if the unit is licensed under Part 35 for medical use. If the unit is not used for medical purposes at all, including not being used for medical research involving human subjects, and is not licensed under Part 35, then 10 CFR 36.51 and conditions of the license addressing training requirements would apply instead, and the instruction specified in 10 CFR 35.610(d) would not be required.