摘要
目的用兆伏（MV）X线平片测定乳腺托架固定下全乳放疗摆位误差，探讨自由呼吸状态下临床靶体积（CTV）外扩至计划靶体积（PTV）的边界。方法选取2010--2012年本科行保乳术后调强放疗的29例乳腺癌患者，其中17例行全乳照射，12例行全乳和锁骨上淋巴引流区照射。均采用乳腺托架体位固定，利用放疗计划系统数字重建图像与治疗期间拍摄正交MV验证平片比较，确定摆位误差。对接受锁骨上淋巴引流区照射与未照射的误差比较行成组t检验。结果全体患者共获得正交MV验证平片图像127套，平均每人（4．4±1．2）套。全组患者左右、上下、前后方向摆位误差分别为（0．9±3．1）、（0．7±3．0）、（1．2±2．1）mm，摆位误差的系统误差分别为3．1、3．0、2．1mm，随机误差分别为2．7、3．3、3．5mm；做与未做锁骨上淋巴引流区照射者的摆位误差无差异（t=0．02、0．20、0．20，P=0．98、0．85、0．85）。CTV至PTv边界左右、上下、前后方向分别为9．6、9．8、7．7mm。结论用乳腺托架固定全乳调强放疗的CTV外放PTV在左右、上下、前后方向上应至少分别为9．6、9．8、7．7mm。
Objective To quantify the setup errors measured with orthogonal megavohage X-ray film in breast cancer patients immobilized in breast bracket. To probe into the margins from clinical target volume （CTV） to planning target volume （PTV） in 3 directions. Methods Repeat orthogonal megavoltage X-ray films were acquired for routine of fine setup verification in 29 breast cancer patients after conserving surgery, 17 received whole breast radiation and 12 received both whole breast and supraelavicular node radiation. All patients were immobilized in the supine position with both arms raised over their heads, using a personalized a-cradle （ breast bracket）. Registrations of the bony anatomy for megavoltage X-ray films to digitally reconstructed-radiographs from the planning CT were compared. Systematic and random setup errors were quantified, and the differences between groups with and without supraclavicular node radiation were compared by independent two-sample t-test. Results The mean set up deviation, systematic error and random error were （0.9±3.1） mm,（0.7±3.0） mm,（1.2±2.1） mm and 3.1 mm, 3.0 mm, 2.1 mm and 2. 7 mm, 3.3 mm, 3.5 mm in the mediolateral, superoinferior and anteroposterior dimensions. There is no difference of set up deviation between patients received supraelavicular node radiation and those did not （t =0. 02,0. 20,0. 20, P =0. 98,0. 85,0. 85）. The margins from CTV to PTV were 9. 6 mm, 9. 8 mm, 7.7 mm in mediolateral, superoinferior and anteroposterior directions. Conclusion For whole breast irradiation patients immobilized with breast bracket, the margins from CTV to PTV were recommended as 9. 6 mm, 9. 8 mm, 7. 7 mm in mediolateral, superoinferior and anteroposterior directions.
出处
《中华放射肿瘤学杂志》
CSCD
北大核心
2013年第3期239-242,共4页
Chinese Journal of Radiation Oncology
关键词
乳腺托架固定
摆位误差
兆伏X线平片
全乳调强放射疗法
Breast bracket immobilized
Setup error
Megavohage X-ray film
Whole breast intensity-modulated radiotherapy
