What is a VQ scan like? How sick do you have to be for the doctor to order the scan?

Takes about 30 min. You breath thru a tube for a couple of minutes and they take some pictures. You get a shot , and they take some more pictures.... Not a hard test. It is orderede for shortness of breath.
Looking for . Pulmonary embolus usually. Can do cta of chest also. See radiologyinfo.Org.