a device and method for treating bodily conduits involves the application of energy to the smooth muscle tissue of the conduit walls to reduce the bulk of smooth muscle tissue and mucus glands . the irradiation treatment of the smooth muscle tissue causes a reduction in the amount of smooth muscle tissue over time which increases the inner diameter of the body conduit for improved fluid flow and prevents smooth muscle spasms . the treatment is particularly useful in the lungs for treatment of asthma to prevent bronchospasms , increase the airway diameter for improved air exchange , and reduce mucus secretions in the lungs .