RSO
Radiation Safety Officer — the named, qualified individual responsible for the radiation-safety program at a facility that handles radioactive materials or radiation-producing equipment. Required by NRC / Agreement-State byproduct-material licenses (Part 35), and by many state X-ray-machine registration frameworks for fluoroscopy and radiation-therapy programs.
Why it matters to buyers: Required for PET / CT, SPECT, brachytherapy, Gamma Knife, and theranostic programs (NRC byproduct license). State fluoroscopy licensing often requires RSO too. Recruiting / credentialing an RSO is a license precondition for new programs — without one, the equipment doesn't operate clinically.
Why it matters to engineers: Documented training, qualifications, and continuing education on file. Program-level responsibility — surveys, dose records, ALARA program, incident response, license amendments. Distinct from the Qualified Medical Physicist role on the linac side, though sometimes the same individual fills both.