Study On Dosimetric Study Of Radiotherapy And Apoplexy In Patients With Early Breast Cancer Breast Cancer In Asia And Its Influencing Factors

Objective:To investigate the dose characteristics of prone position radiotherapy after breast conserving surgery in breast cancer. Explore whether whole-breast prone radiotherapy is beneficial for Asian women with small-volume breasts. Probe to other factors and breast cancer radiotherapy dosimetry relationship such as thorax shape, and compare the differences prone position and supine position.Methods:Included in patients after breast-conserving surgery for Stage O-I cancer of the left breast, and with pathological examination sentinel lymph node negative. Patients underwent computed tomography (CT) simulation in the prone and supine positions.The CTV and organs-at-risk (OARs) were contoured on the CT slices by one radiation oncologist and verified by another. Collected and statistics the general information and dosimetry parameters of patients.Results:1) .The volume of the CTV in prone position is slightly larger than then it in supine position(p<0.05);But the conformity index (CI) and the homogeneity index(HI) were not statistically different, and V105%,V95% in prone position is less than supine position.2) . There was no significant difference about the volume of the left lung between the two positions,but the dose of the left lung in prone position,both V5, V10, V20,or the mean dose of the left lung has obvious advantages, was significantly lower than the supine position, ,with statistically significant. The heart doses and the mean dose of LAD is also significantly higher in prone position. There was no significant difference in the dose of the right breast in both positions.3) .Among left breast cancer patients, the prone position was always superior in 7/9 of women with breast volumes of>500cm3, and in 3/17 of women with breast volumes of<500cm3.4) .D-lung and TPR were positively correlated with the dose of ipsilateral lung,and the difference between D-lung and TPR was negatively correlated with the mean dose of prone position and supine position (ADmdh).5).The mean dose of the heart in the inspiratory state is more likely to benefit.Conclusion:Prone position with good protection for ipsilateral lung against radiation, but for some patients, the dose of the heart increased, due to the drop in the prone position heart; D-lung, TPR can be used as an excellent measure of the degree of protrusion of the ipsilateral thorax to predict the dose of the lung for breast cancer patients; Deep breath-hold hold may be a way to solve the high dose of breast cancer in prone position for radiotherapy. The small breast volume women in Asian may not be able to do left breast cancer radiotherapy with prone position, should be chest wall shape,breast size, respiratory control and other comprehensive into assessment;...