Do I need a commercial broker?

Thinking of buying a small office approx 600sf - 900sf, 57th and 6th/7th area (flex). 1 room poss convert to 2 small rooms plus waiting room. To be used as psychiatrists office. Dont really want the clients to have to sign in but need a doorman/front desk. Some of the commercial rental offices/spaces do this but can I buy one? I am not a psychiatrist btw... doing my own research I am only coming up with residential condos and the occasional broker. Can anyone tell me best way to go about this pls - I have checked out cityfeet, is this the best site for this info? Do I need a buyers broker? Are there any good coops/condos that could work? thanks