目的:分析腹板俯卧定位中因腹部位置不确定所导致的定位误差,研究其对定位精度的影响,并通过使用自制泡沫垫板为腹托来减小摆位误差,提高摆位精度.方法:随机选取26例腹板俯卧定位的直肠癌术后放疗患者,并分为A、B2组(A组14例,B组12例)进行CT模拟定位.A组采用腹板加自制泡沫垫板定位,B组只采用腹板定位.在模拟定位机上对每例患者重复摆位,取0、90、270°机架角度透视影像与治疗计划生成的数字重建影像(digitally reconstructed radiograph,DRR)进行比对,分析三维方向的摆位误差.比较2组患者小肠的最大剂量、平均剂量、V50及V40,并对2组数据作独立样本t检验.结果:A组相对于B组,X方向的误差为(0.16±0.07)cm vs(0.17±0.09)cm (P=0.94),Y方向的误差为(0.22±0.09)cm vs (0.32±0.09)cm(P=0.01),Z方向的误差为(0.23±0.08)cm vs(0.42±0.12)cm(P=0.00).2组在X方向上的摆位误差及重复性无统计学差异,但在Y、Z方向上有显著性差异.2组小肠最大剂量、平均剂量、V50及V40无显著性差异.结论:腹板加自制泡沫垫板的固定技术在不增加小肠受量的同时,较大地改善了因腹部悬空位置不定原因导致的定位误差问题,而且具有实施方法简便、摆位误差小及重复性良好等特点,值得临床推广应用.
Objective Y-axis laser positioning ruler of body Gamma knife developed by our department can help smoothly implement a patient's treatment plan in terms of therapeutic equipment.Methods Y-axis laser positioning ruler is composed with horizontal base,graduation ruler,slide card,laser pen and scale pointer,can be easily operated.Results 38 cases of the control group were smoothly accomplished in Y-axis direction and the passing rate was 76%.For the experimental group,50 Y-axis-direction treatment plans were all successful,representing a passing rate of 100%.Conclusion The use of Y-axis laser positioning ruler of body gamma knife prevents a situation that the treatment plan can not be realized as numerical value of Y axis is beyond feasible scope;moreover,it enhances work efficiency, shortens treatment period and guarantees safe therapy for patient.
Objective To investigate the difference of base tear secretion,when schirmer tear strips hung on the different parts of lower eyelid,in order to choose a suitable suspension position.Methods Prospective study.30 cases(60 eyes) were involved.Schirmer tear strips hung on the medial or lateral lower eyelid(random order).Record the length of schirmer tear strips discoloration after 5 minutes,the length is Schirmer value.After a break of 3 minutes,to do the other side Schirmer test,T test and Bland-Altman analysis were used to evaluate the consistency of two Schirmer test results.Results The medial and lateral Schirmer value were 6.94±5.34 mm and 7.33±5.88 mm(P>0.05).There was a significant positive correlation(r= 0.989,P=0.000),and the agreement of two results was well.Conclusion The hunging position of Schirmer tear strips may not affect the detection of basal tear secretion.lateral lower eyelid wide and easy to operate,I recommend that Schirmer tear strips hung on the lateral lower eyelid.
