肺密度校正对食管癌治疗靶区剂量的影响

The influence of lung correction on the target dose in radiation treatment of esophageal carcinoma

目的 :研究并探讨执行食管癌放疗计划过程中肺密度校正的临床意义。材料与方法 :利用治疗计划系统 ,选取中段食管癌为模型 ,采用前 1,后 2斜野技术。比较肺密度 1.0 (未校正 ) ,和 0 .33、0 .2 0(已校正 )时靶区吸收剂量差异。结果 :显示利用 60 Co线、5 MV- X线、8MV- X线 ,18MV- X线治疗食管癌若不做肺校正则大多数病人靶区实际吸收剂量比原处方剂量分别增加 2 4 %～ 2 8%、18%～ 2 1%、13%～ 15 %、7%～ 9%。结论 :提示采用能量低的射线 ,如 60 Co、5 MV以下

Purpose: To evaluate the influence of lung corrections on the target volume dose in radiation treatment of esophageal carcinoma by TPS HEVAPLAN. Materials and Methods: Three radiation field technique to middle esophagus were used as the model of this investigation .target volume doses were calculated with photons in different energies to compare with the divergence when the lung density were set to 1.0(without lung correction) 0.33 and 0.2 (with lung correction).Results: If no lung correction was performed, the actual radiation dose in target volume were 24%～28%, 18%～21%, 13%～15% and 7%～9% which were radiated with 60 Co, X-ray of 5MV, 8MV and 19MV. Conclusion: The lung density must be corrected in treating 60 Co unit.