Continuous Airway Pressure for Hypofractionation and SBRT Planning and Treatment

Respiration-induced tumor motion is a major challenge in achieving high-precision radiation therapy (RT) for lesions within the thorax and upper abdomen. Recent studies demonstrated that, in most patients, continuous airway positive pressure (CPAP) increases lung volume by a third and hence displaces part of the healthy lung and the heart out of the RT field. In some patients, CPAP also decreased the amplitude of respiration-induced tumor motion and thus reduced the planning target volume (PTV). The little need for patient cooperation and easy workflow makes CPAP a potential solution for the challenge of treating moving targets with RT. In this chapter, we will explore an alternative innovative strategy to reproduce the favorable anatomy and tumor motion reduction associated with the deep inspiratory breath hold (DIBH) technique using CPAP, which is the administration of positive pressure to the airways during the entire respiratory cycle.