Dosimetric comparison for active breathing coordinator reduces radiation dose to the heart and lungs in patients with left breast cancer using VMAT techniques

For women with left-sided breast cancer, there is risk of potential cardiotoxicity from the radiation therapy. Different breath-hold methods have been utilized. The two dominant methods are the spirometry-based active breathing coordinator (ABC R3.0) system (Elekta Ltd, Crawley, UK) and the video-based real-time position management (RPM) system (Varian Medical Systems, Palo Alto, USA). The ABC device was developed at the Manipal Hospital Vijayawada, AP. The device is essentially a mouth piece attached to a spirometer and the patient's nose is pegged to ensure they are breathing only through the device. As the spirometer is connected to a computer, the Radiation Teams are able to visualize the patient's level of inspiration. Once the patient has reached the required threshold, pinch valves in the spirometer remotely close, preventing the patient from exhaling or inhaling outside the required threshold. A wide array of planning techniques has been reported in the DIBH literature, but one planning study compared VMAT-Deep Inspiration Breath-Hold (DIBH) Technique and VMAT-Free-Breathing (FB) Technique. DIBH allows this potentially superior planning technique to be used while minimizing cardiac dose