左乳癌改良根治术后放疗中不同照射技术的剂量学研究

Dosimetric Study of Different Irradiation Techniques in Postoperative Radiotherapy for Modified Radical Mastectomy for Left Breast Cancer

目的分析左乳癌改良根治术后胸壁、内乳及锁骨上淋巴结放疗中不同放射治疗技术的剂量学特点。方法通过在Elekta Monaco治疗计划系统中对10例左乳癌改良根治术患者分别制定混合射线照射方式(3DCRT+elec)、调强放射治疗(Intensity Modulated Radiation Therapy,IMRT)、分段弧段旋转容积调强(VMATpart)和连续弧段旋转容积调强(VMATcont)四种放射治疗计划,比较分析CTV、肺、心脏、左冠状动脉前支区域、右乳和甲状腺的各项剂量参数。结果左乳癌改良根治术后的患者采用3DCRT+elec照射,靶区剂量较差但对正常器官的保护较好,IMRT、VMATpart和VMATcont计划靶区均具有好的均匀性和适形度,其中VMATcont计划中左肺、左冠状动脉前支区域和心脏的高剂量区域体积要低于其他三种照射方式。结论在临床实践中医学物理师可制定多种计划方式根据临床需要进行个性化选择,VMATcont具有潜在的优势。

Objectives To analyze the dosimetric characteristics of different radiotherapy techniques in chest wall,internal breast and supraclavicular lymph node radiotherapy after modified radical mastectomy for left breast cancer.Methods In the Elekta Monaco treatment planning system,10 patients with modified radical mastectomy of left breast cancer were respectively formulated with mixed ray irradiation(3DCRT+elec),intensity-modulated radiation therapy(IMRT),segmented arc rotation volume intensity modulation(VMATpart)and continuous arc rotation volume modulation(VMATcont)four kinds of radiation treatment plans,comparative analysis of CTV,lung,heart,left coronary artery anterior branch area,right breast and thyroid dose parameters.Results For patients after modified radical mastectomy of left breast cancer irradiated with 3DCRT+elec,the target area dose is inferior but the protection of normal organs is better.For IMRT,VMATpart and VMATcont plan,the target area has good uniformity and conformity.For VMATcont plan,the volume of the high-dose area in the middle-left lung,the left anterior branch of the coronary artery,and the heart is lower than the other three irradiation methods.Conlusion In clinical practice,medical physicists can formulate a variety of planning methods to make personalized choices according to clinical needs.Generally,VMATcont has potential advantages.