Comparison of dose sparing between visual feedback guided- and active breathing coordinator-assisted- deep inspiration breath hold for left whole breast radiotherapy

To compare the benefits of dosimetry between different deep inspiration breath hold (DIBH) techniques. A total of sixty patients eligible for adjuvant left whole-breast radiotherapy were enrolled, with equal allocation ( n =30 per group) to either vDIBH or ABC-DIBH techniques. All patients received computed tomography (CT) scans in both free breathing (FB)and DIBH states. The target and crucial organs at risks (OARs) were precisely delineated on both breathing states of CT scans. The primary endpoints focused on assessing the irradiation exposure to OARs, including the heart, left anterior descending coronary (LAD) artery, left lung and stomach. The dose sparing advantage was more pronounced with vDIBH compared to ABC-DIBH, correlating with its enhanced lung expansion capacity. The relative dose reduction of heart's mean dose (32%±18% vs . 22%±15%, P =0.018) and LAD artery's mean dose (43%±25% vs. 30±16%, P =0.023) were improved with vDIBH comparing with ABC-DIBH. However, regardless of whether vDIBH or ABC-DIBH was employed, our study did not demonstrate the protective effect of DIBH on the left lung. The vDIBH group demonstrated a remarkable dose reduction for OARs mentioned above compared to the ABC-DIBH group, attributed to greater lung inflation during vDIBH.