热塑膜固定联合π形尺摆位在腹部肿瘤患者放疗中的应用

Application of Combination of Thermoplastic Film Fixation andπ-Shaped Ruler Positioning in Radiotherapy for Abdominal Tumors

目的：探讨热塑膜固定联合π形尺摆位在腹部肿瘤患者放疗中的临床应用价值。方法选取我院2013年12月-2014年3月12例腹部肿瘤患者，均在模拟定位机下做膜和标记魔十字，并在动度较小的骨性标记处的皮肤上标记π形尺激光点，然后摄取其正侧位DR图像；复位时A组使用热塑膜固定摆位，B组使用热塑膜固定联合π形尺摆位，分别摄取两组正侧位DR图像；将复位与做膜时摄取的正侧位DR图像进行二维配准，测量摆位误差。结果B组与A组在X、Y、Z轴方向上的摆位误差均值分别为3.40、4.59、6.92 mm和6.63、7.35、8.15 mm。B组摆位误差小于A组，两组差异有统计学意义（P＆lt;0.05）。结论热塑膜固定联合π形尺摆位比单独使用热塑膜固定摆位更准确，可有效减小摆位误差。

Objective To investigate the effectiveness of application of combination of thermoplastic iflm ifxation andπ-shaped ruler positioning in radiotherapy for patients with abdominal tumors. Methods Altogether 12 cases with good self-control ability were selected among abdominal tumor patients who had been treated in the hospital from December 2013 to March 2014. For all the patients, the iflm was made, the magic cross was marked, the skin at the bony landmarks with the smaller dynamic degree was marked with aπ-shaped laser point when they lay on the simulation localization machine. Then, the anteroposterior and lateral DR （Digital Radiography） images were taken. During the restoration, two positioning methods were adopted：the direct positioning of thermoplastic iflm ifxation was adopted in Group A;Group B used the combination of thermoplastic iflm ifxation andπ-shaped ruler positioning. The anteroposterior and lateral DR images were taken. The two-dimensional image matching was performed between images taken during restoration and iflm-making to measure the error. Results The absolute value of errors （mm） between the positioning in X, Y and Z directions of Group B and Group A were respectively 3.40, 4.59, 6.92 mm and 6.63, 7.35, 8.15 mm. The errors significantly decreased when the combination of the thermoplastic film fixation and π-shaped ruler positioning was adopted. The difference of the errors between two positioning methods was statistically significant （P＆lt;0.05）. Conclusion Application of combination of the thermoplastic iflm ifxation andπ-shaped ruler positioning demonstrated its superior accuracy over the single use of the thermoplastic film fixation, which can effectively reduce errors caused by the positioning.