颈部肌群训练减少鼻咽癌放疗摆位误差的前瞻性临床研究

Prospective clinical study of effect of neck muscle training on reducing setup error of radiotherapy for nasopharyngeal carcinoma

目的:在RayStation质子治疗计划系统(TPS)中为三台CT设备进行建模,验证并校准CT建模曲线。方法:使用CT设备扫描模体得到不同组织替代材料的CT值,建立CT值与质量密度(CT-MD)曲线。同时,根据各种人体组织的化学成分,计算得到CT值与阻止本领(CT-SP)曲线。在TPS中使用不同CT建模曲线计算组织替代模块的等效水厚度;利用布拉格峰测量设备测得各模块实际等效水厚度,与TPS计算值进行比较,验证不同CT建模的精度。结果:不同管电压扫描条件下,CT建模曲线差异有统计学意义。基于化学成分校准的CT-SP曲线与CT-MD曲线比较更适合质子剂量计算,但对高CT值对应的阻止本领值仍需进行修正,校准后的计算误差在3%以内。结论:本文阐述的在质子TPS中验证并校准CT值曲线的方法,证明了化学成分计量校准后的CT-SP曲线更适用于质子剂量计算。

ObjectiveTo evaluate the effect of neck muscle training on reducing the neck setup error during radiotherapy in patients with nasopharyngeal carcinoma.MethodsClinical data of nasopharyngeal carcinoma patients who were treated with radiotherapy in the First Affiliated Hospital of Air Force Medical University from February 2021 to October 2022 were selected and analyzed.All subjects were randomly divided into the experimental group(n=48)and control group(n=51)at a ratio of 1:1 using a random number table method.In the experimental group,patients received neck muscle training prior to treatment,and those in the control group received conventional treatment without additional interventions.Cone beam computed tomography(CBCT)was performed weekly to measure and analyze the setup errors at the level of the slopes,4th cervical vertebra(C4)and 7th cervical vertebra(C7).The four-dimensional displacement[left-right(LR),superior-inferior(SI),anterior-posterior(AP),rotation(Rtn)]systematic errors and random errors at each level were calculated,and the planning target volume(PTV)boundary was calculated.The differences at three different levels of slope,C4,C7(LR,SI,AP axis)were compared between two groups.The correlation of setup errors in each direction was analyzed by Spearman correlation analysis.The changes of cervical curvature,cutaneous toxicity(common terminology criteria for adverse events V3.0)and pain assessment(numerical rating scale)were compared between two groups.Qualitative data between two groups were compared byχ2 test.Quantitative data between two groups were compared by t-test.ResultsBaseline features were well balanced in both groups.The setup error in the experimental group was smaller than that in the control group.For the setup error in the AP direction,the setup errors at the levels of slope,C4 and C7 in the experimental group were(0.94±0.88)mm,(1.13±1.03)mm and(1.32±1.22)mm,significantly less than(1.66±1.23)mm,(1.63±1.35)mm and(1.89±1.48)mm in the control group(all P<0.001).In the SI direction,the setup errors at the levels of slope,C4 and C7 in the experimental group were(1.14±0.87)mm,(1.31±0.93)mm and(1.39±0.95)mm,compared with(1.22±0.95)mm,(1.40±1.11)mm and(1.52±1.08)mm in the control group(P=0.278,0.272,0.100).The differences in the AP direction at the level of C4 and C7 in the experimental group were smaller than those in the control group(P=0.014,0.005).The required PTV boundary in the AP direction in the experimental group was increased from 1.77 mm at the slope level to 2.98 mm at the level of C7.In the control group,it was increased from 3.02 mm at the slope level to 4.78 mm at the level of C7.Correlation analysis showed that at the C4 and C7 levels,and the setup errors in the SI direction were moderately negatively correlated with those in the AR direction.There were no significant differences in cervical curvature,skin toxicity and pain assessment between two groups.ConclusionNeck muscle training can reduce the setup error in the AP direction and PTV boundary of radiotherapy in patients with nasopharyngeal carcinoma,which is worthy of clinical promotion.