You are getting into an area grey enough that you better get the "real" opinion from your AHJ. I think the Xray machine will make this a medical establishment in his opinion but that is just my opinion.
I agree with Greg, it's a call to be made by someone other than the electrical inspector or the electrician. Look on the plans and see if they say "clinic" and if it does, 517 applies. What are your concerns? Wiring methods, Hospital Grade receptacles, back up power?
Just my 2 cents, but I would ask the AHJ. If there are machines, that touch a "patient",(doctor or not) then I would go with sec. 517 of the NEC. If there are no machines that touch a patient, then I don't believe you would need it. I would get a letter in writing from the "Doctor"/chiro people for your records stating that there will not be any machines touching people. This might help protect you.
Thanks for the replies. I will contact the AHJ before I proceed. My biggest concern is the builbing was not a doctors office but was purchased by a chiropractor to set up shop. I have no problems making my work comply with 517, but I am afraid the inspector will say all the old work needs to be re done to comply. I know the chiropractor has no idea what he might be getting in to here, he might end up spending quite a bit more than he figured on. He will probably want to sue the realtor for not informing him the building was not suitable for his practice with the current wiring methods.
Just have him minimize the "patient care areas" on the plans. Office space, waiting rooms and dressing rooms are exempt. What is the current wiring method. If it is wire in pipe with a EGC pulled you might not be in much trouble at all.