Breast cancer DIBH (Deep Inspiration Breath Hold) radiotherapy represents a high-precision treatment approach that substantially minimizes radiation exposure to vital organs such as the heart, thus enhancing protection of the patient's heart, lungs, contralateral breast, and other normal tissues compared to conventional radiotherapy techniques. This method requires meticulous precision, necessitating that patients possess exceptional respiratory control, which is facilitated through specialized equipment. Without such control, patients may encounter issues like missed targets, significant setup errors, and extended treatment durations. In this study, the research team employed portable devices to enable patients to independently perform daily respiratory training exercises. The control group received no such devices; instead, these patients were merely instructed verbally on the importance of improving their breath-holding capabilities. The effectiveness of this intervention was evaluated by comparing the daily setup errors between the two groups. Additionally, the intervention's influence on patient outcomes was assessed by monitoring the toxicity and side effects experienced by the patients.