CPAP for Motion Management in Breast Radiotherapy; and Lung & Liver SABR

A phase II trial to determine the proportion of patients where the use of continuous positive airway pressure (CPAP) results in a superior radiation plan compared to standard planning procedures. The rationale for using CPAP with radiotherapy is based on its ability to increase the tidal volume, flatten the diaphragm thus reducing respiratory excursions.The resultant lung hyperinflation and reduced respiratory excursions can be harnessed for radiotherapy purposes by:

1. Displacing the heart away from the radiotherapy field 2. Reducing the volume of functional lung irradiated 3. Reducing the radiotherapy target motion

CPAP has been shown to be superior to free breathing radiotherapy (RT), however it remains unclear how much benefit it confers vs other motion management adjuncts such as deep inspiration breath hold (DIBH) or 4-DCT.