Dosimetric comparison of DIBH and FB for left-sided breast cancer radiation therapy.

This study compared deep inspiration breath-hold (DIBH) versus free-breathing (FB) techniques in postoperative radiotherapy for left-sided breast cancer. Dosimetric parameters for 94 patients were analyzed. DIBH significantly improved target conformity while reducing cardiac exposure, with mean heart dose decreasing by 2.631 Gy (EQD2). Significant dose reductions were also observed in bilateral lungs, esophagus, and spinal cord. A weak correlation was identified between left lung volume expansion and organ-at-risk dose reduction. Receiver operating characteristic analysis determined that a left lung volume increase of 807.1 cc predicted clinically meaningful cardiac protection. DIBH demonstrates effective organ sparing while only marginally compromising target coverage. Additionally, lung volume expansion could serve as a potential patient selection criterion.