上肢位置变化对胸部肿瘤患者放疗摆位精度的影响

目的:探讨上肢位置变化对胸部放疗患者等中心摆位标记点位置的影响,验证误差范围,提高放疗摆位精度。方法:模拟10例采用热塑体膜固定的胸部肿瘤患者在放疗摆位中上肢位置变化的三种场景:A,双手十指交叉额前(取为标准位置)、B,双手互握肘部额前、C,双手十指交叉额顶,分别测量等中心摆位标记点在三维方向上受牵拉而移动情况。结果:三种上肢位置的变化均使胸部的摆位标记点产生了偏移,主要影响Y和Z方向,与标准位置相比互握肘部所产生偏移最大,Y方向最大偏移距离达10mm,Z方向最大偏移距离达12mm;同一上肢位置(标准位置A或C)摆位测量结果显示偏移距离小于5mm,在摆位误差允许范围内。结论:热塑体膜固定放疗实践中,患者双手位置的变化对放疗摆位标记点均有影响,进而直接影响放射治疗的精度。

The effect of the position change of the upper limbs to the setup accuracy of the thoracic cancer patients

Objective To explore the position change of the isocenter setup markers on the sternum due to the change of upper limbs.Verify the error range and improve the setup accuracy.Methods Three upper limbs positions were simulated for 10 patients immobilized by using thermoplastic film and the isocenter setup markers on the sternum skin were compared with markers on the thermoplastic film while the upper limbs different positions.Results The isocenter setup markers on the sternum skin were deviated by all three upper limbs position.The maximum deviated distance was caused by position B and it was10 mm and 12 mm in Y and X direction.Deviated distance in the same upper limbs position（A or C）is in the acceptable range（they are smaller than 5 mm in three-dimensional direction）.Conclusion The change of the upper limbs position can affect the position of isocenter setup markers on the sternum of the patients and the precision of radiotherapy.