I've had exercise-induced athsma for years. My doc didn't schedule scans or anything more aggressive than good ol' ventalin inhalers. I avoid the use of the inhaler at all costs, since I find that I can become dependent on it. Instead, if I ever start not being able to breathe, I slug back some DM decongestant with an expectorant in it. The booze in the medicine relaxes me [not as well as a nice Petit Verdot], the DM reduces the tendency to cough, and the decongestant and expectorant help clear out the lungs. It might be even more effective than the inhaler, since I can't inhale properly.