热塑膜联合发泡胶固定技术在宫颈癌放疗中的应用价值

Application value of thermoplastic film combined with styrofoam fixation technology in radiotherapy for cervical cancer

目的:利用锥形束CT(CBCT)技术分析盆部热塑膜联合发泡胶和单纯盆部热塑膜这两种固定方法在宫颈癌放疗时的摆位误差。方法:分别对13例盆部热塑膜联合发泡胶固定的62次CBCT、14例单纯盆部热塑膜固定的71次CBCT数据进行回顾性分析,并比较两种固定方式在左右(Lat)、前后(Vrt)、头足(Lng)和床转角(Rtn)这4个方向上的摆位误差及其分布情况。结果:在Lat、Vrt和Lng这3个方向上的摆位误差均在5 mm以内,而Rtn也在3°以内,符合临床治疗要求。两种固定方式在Lat和Rtn方向上的摆位误差无统计学意义(P>0.05),但相比单纯盆部热塑膜固定,盆部热塑膜联合发泡胶固定在Vrt和Lng方向上具有较好的稳定性(P=0.018、0.002)。盆膜联合发泡胶固定≤3 mm的分布情况:Lat 61次(98.39%)、Vrt 59次(95.16%)、Lng 58次(93.55%);单纯盆膜固定≤3 mm的分布情况:Lat 63次(88.73%)、Vrt 58次(81.69%)、Lng 54次(76.06%)。结论:盆部热塑膜联合发泡胶固定技术在Vrt和Lng方向的稳定性优于单纯盆部热塑膜固定技术。

Objective To apply cone beam computed tomography(CBCT) for comparing the setup errors in cervical cancer radiotherapy using pelvic thermoplastic film combined with styrofoam fixation technology vs pelvic thermoplastic film fixation.Methods The data gathered from 62 CBCT of 13 cases of pelvic thermoplastic film combined with styrofoam fixation and 71 CBCT of 14 cases of pelvic thermoplastic film fixation were retrospectively analyzed. The setup errors and its distribution in 4 directions, namely left-right(Lat), front-back(Vrt), head-foot(Lng) and bed angle(Rtn), were analyzed. Results The setup errors in Lat, Vrt and Lng directions were within 5 mm and Rtn error was within 3°, which accorded with the requirements of clinical treatment. No statistical difference was found in the setup errors in Lat and Rtn directions between the two kinds of fixations(P>0.05). Compared with pelvic thermoplastic film fixation, pelvic thermoplastic film combined with styrofoam fixation achieved a better stability of Vrt and Lng directions(P=0.018, 0.002). When pelvic thermoplastic film combined with styrofoam fixation was adopted, there were 61 times(98.39%) of setup errors ≤3 mm in Lat direction, 59 times(95.16%) in Vrt direction and 58 times(93.55%) in Lng direction. When only pelvic thermoplastic film fixation was adopted, there were 63 times(88.73%)of setup errors ≤3 mm in Lat direction, 58 times(81.69%) in Vrt direction and 54 times(76.06%) in Lng direction. Conclusion Pelvic thermoplastic film combined with styrofoam fixation is superior to pelvic thermoplastic film fixation in the stability of Vrt and Lng directions.