摘要目的 探讨发泡胶与乳腺托架在乳腺癌保乳术后IMRT体位固定中的精度差异.方法 选取2018年2-8月中山大学孙逸仙纪念医院收治保乳术后全乳大分割IMRT(42.56 Gy分16次)的乳腺癌患者24例,随机分为发泡胶组和乳腺托架组.使用CBCT于患者第1、3、5、7、9、11次治疗前拍摄正侧位KV图像在线匹配获得两组患者在左右、头脚、腹背的摆位误差,记录两组摆位时间.采用独立样本t检验分析两组间摆位误差,并计算PTV分次间摆位误差的外扩值.结果 发泡胶组和乳腺托架组在左右、头脚、腹背方向的摆位误差分别为(2.36± 1.89)mm与(2.56±2.05) mm (P=0.49)、(1.76±1.78) mm与(3.28±2.79) mm (P＜0.05)、(1.47± 1.49) mm与(1.73±1.81) mm (P=0.28);CTV向PTV分次摆位误差的外扩值分别为2.97、2.92、2.21 mm与3.41、4.09、2.59 mm;单次摆位时间分别为(3.4±1.1) min与(5.5±3.1) min (P=0.01).结论 相较乳腺托架,发泡胶的摆位精度明显提升且效率更高.

abstractsObjective To investigate the difference of styrofoam and breast carrier in postposition fixation of intensity-modulated radiotherapy after breast conservative surgery for breast cancer patients.Methods From February 2018 to August 2018,tweenty-four patients with breast cancer in Sun Yet-Sen Memorial Hospital of Sun Yet-sen University were selected for this study,who underwent hypofactionationed radiotherapy after breast conservative surgery with total dose 42.56 Gy/16Fractions.They were randomized into styrofoam test group and breastcarrier control group.Cone beam CT as used to record the positioning error under the directions of left and right (x),head and foot (y),abdomen and back (y) within two groups at the first,third,fifth,seventh,eleventh time before irradiation.Furthermore,the PTV extension margin was calculated and the positioning time of two groups was recorded.Two sets of pendulum errors were analyzed by independent sample T-test,and the outspread value of inter-fractional set up error of the PTV was calculated.Results The errors of the test group and the control group in the direction of x,y,z were as follows:(2.36±1.89) and (2.56±2.05) mm (P=0.49),(1.76± 1.78) and (3.28±2.79) mm (P＜0.05),(1.47± 1.49) and (1.73± 1.81) mm (P=0.28).The extension values of inter-fractional set up error of CTV to PTV were 2.97,2.92,2.21 mm and 3.41,4.09,2.59 mm respectively.The time of single positioning was (3.4± 1.1) and (5.5 ± 3.1) min respectively (P=0.01).Conclusion Styrofoam has better positioning accuracy and efficiency compared with breast carrier.