Dose Comparision Of Left-breast Carcinoma After Breast-conserving Surgery Using Three Radiation Therapy Technique

Volumetric modulated arc therapy techniques has many advantages, such as less therapy times,less dose of the OAR and the target has better CI than other techniques.With VMAT be use in the therapy of breast carcinoma,tumor target be leakage due to patient's breathing. 4D-CT scaning,acqured 10 breathing phase image information,thoracic breathing after the analysis of dynamic threshold.Take as threshold as value of MLC expansion.In this way,solve the problem of target leakage.4D-CT scaning,acqured 10 breathing phase image information, thoracic breathing after the analysis of dynamic threshold. Delineate tumor target and OAR, the therapy planning was performed by three radiotherapy techniques.The Tumor prescription dosewas 50 Gy,all kind of plans has the same prescription dose.Comparision of three irradiation technology from the target and OAR. The radiation therapy times were also compared. Acquired the breath threshold by 4D-CT. Used this value as a range of the MLC expansion.Compare with other irradiation technology, VMAT improved significantly the dose conformity index of target volume. VMAT increased the V5% of organs at risk(heart and lung), but reduce the V30, V40 of the heart.The VMAT has the shortest therapy times in the three irradiation technology.VMAT improved significantly CI and HI of target volume,increased the irradiation doses of OAR and decreased therapy times.But the OAR volume of the low dose has be increased.