Dosimetry of moderate deep inspiration breath hold achieved using an active breathing control device in the target of forward whole-breast intensity-modulated radiotherapy after breast conserving surgery in breast cancer

OBJECTIVE:To evaluate the dosimetry advantages of moderate deep inspiration breath hold(mDIBH) achieved using an active breathing control(ABC) device in the target of forward whole-breast intensity-modulated radiotherapy after breast conserving surgery in breast cancer.METHODS: 18 patients after breast conserving surgery had received primary CT-simulation assisted by ABC to get two sets of CT image on the two breathing conditions which included one set from free breath(FB),and the other set from mDIBH.Forward whole-breast intensity-modulated radiotherapy plans were carried out in each set of CT image using Pinnacle7.4 f planning systems and the differences of two plans had been compared.RESULTS: The coverage index and habituation index of the plans in FB were similar with those in mDIBH(1.08±0.01) vs(1.09±0.01),P=0.776;0.59±0.08 vs 0.60±0.04,P=0.821).The V20 and V30 of Ipsilateral lung in FB were higher than those in mDIBH(13.07±3.93)% vs(9.75±3.58)%,(11.68±3.90)% vs(8.12±3.23)%,P=0.000;In the left breast cancer,The V20 and V30 of heart in FB were higher than those in mDIBH(5.42±3.21)% vs(2.73±1.95)%,(3.70±2.84)% vs(1.48±0.22)%,P0.05.CONCLUSION: Compared with FB,mDIBH achieved using an ABC device significantly reduces heart and lung doses in the target of forward whole-breast intensity-modulated radiotherapy after breast conserving surgery in breast cancer.