Clinical Radiation Dosimetric Analysis For Postmastectomy Three-dimensional Conformal Radiation Therapy Of The Chest Wall

Breast cancer is a common female malignancy. Radiation therapy is one of effective treatments for breast cancer, and postoperative radiotherapy of breast cancer is the most comprehensive treatment. Postoperative radiotherapy can reduce the local recurrence rate of high-risk breast cancer after the modified radical mastectomy in patients and disease free survival. Now, the modified radical mastectomy is still the main method of surgical treatment of breast cancer in domestic. According to incomplete statistics, it is about95% of all, so it is especially important in domestic to radiation therapy′s reasonable applications after the modified radical mastectomy.Object:We compared the dose distribution in chest wall of patients who have received breast cancer surgery (or radical, modified radical mastectomy) with 3D-CRT to that with electronic wire perpendicular irradiation.Method:In this paper, we compared 12 patients who received 3D-CRT in chest wall after breast cancer surgery (or radical, modified radical mastectomy) to 12 patients who received electronic wire irradiation, and approached the clinical value of 3D-CRT.The operation procedure is below: (1) position on the breast bracket; (2) CT mimotope; (3) institute treatment plan; (3) mark off target regions; (5) optimize treatment plan; (6) verify treatment plan; (7) put treatment into practice.All statistical analyses were performed with the SPSS 13.0.We irradated the patients′chest wall who have received breast cancer surgery (or radical, modified radical mastectomy) in 6MV X-ray tangent exposure field with 3D-CRT. The result is that the minimum dose is in the skin surface; the maximum dose is in the target area; the target area surrounded by 95% isodose curve is better; the radiation dosage in normal lung tissue in suffering side is low. Correspondingly with electronic wire, the dose in target area is maldistribution; the dose in surface and margin is not satisfactory; the radiation dosage in normal lung tissue in suffering side is high. All the above results indicated that 3D-CRT group was superior to the group with electronic wire irradiation alone.Result:It is especially important for the patients after breast cancer surgery (or radical, modified radical mastectomy) to proceed postoperative radiotherapy in chest wall after surgery. However, because of individual differences in chest wall and the normal tissues (including lung and other tissues) in the irradiation zones, it is diffcult to reach a consensus on using which method to irradiat chest wall. In this paper, we compared the patients who have received breast cancer surgery (or radical, modified radical mastectomy) with 3D-CRT to that with electronic wire perpendicular irradiation, and found that it is better in homogeneity to irradate chest wall with 3D-CRT, and found that the radiation dosage in normal lung tissue in suffering side is low.So it is worth to promote in clinic.