Evaluation of the effect of deep inspiration breath-hold on radiation therapy for left breast cancer and the correlation between cardiac chest wall contact distance and cardiac exposure / 中国综合临床

ABSTRACT

Objective To compare the exposure to heart and other organs of the application of DIBH (deep inspiration breath-hold)and FB(free breath)in the left breast cancer radiotherapy,and the relationship between CCD(cardiac contact distance)and heart dose was analyzed.Methods Thirty patients with left breast cancer were examined with CT scans using DIBH and FB respectively,and then the dose was calculated by TPS(treatment planning system).The dose of heart,left anterior descending branch and left ventricle were analyzed by DVH(dose volume histogram).FB-CCDax(Axial cardiac chest wall contact distance)and FB-CCDps(sagittal heart chest wall contact distance)in CT images were measured based on FB.Results The parameters showed that,in radiotherapy with the application of DBIH technology,the irradiated volume of heart, left anterior descending branch(LAD),left ventricle(LV)of were significantly lower than that in the organs in the FB,the mean dose(Dmean)of heart of the former was 0.8 Gy,compared with 2.7 Gy in the latter one(P<0.005).The Dmean of LAD was 4.0Gy,compared with 12.7Gy in the latter one(P<0.001); The Dmean of LV was 1.2Gy,compared with 3.6Gy in the latter one(P<0.005).In the DIBH and FB radiotherapy,the Dmean of the heart,left anterior descending branch and left ventricle was correlated with FB-CCDps,but not with FB-CCDax.Conclusion DIBH is a simple treatment technique that can effectively reduce the cardiac radiation dose without loss of target dose.FB-CCDps is a potential predictor of cardiac exposure,and the longer the FB-CCDps distance is,the higher the cardiac dose is.The study found that at least 70% of patients with left breast cancer would benefit from DIBH and reduce the radiation exposure to normal cardiac structures,so DIBH should be used as a routine clinical application.