| 王丹,刘明远,修霞,高鸿,李高峰.PET-CT靶区勾画方式对肺癌治疗计划的影响[J].中华放射医学与防护杂志,2008,28(4):368-370 |
| PET-CT靶区勾画方式对肺癌治疗计划的影响 |
| Effect of radiotherapy planning using different methods PET-CT defining the target volumes for lung cancer patients |
| 投稿时间：2007-10-25 |
| DOI： |
| 中文关键词: 肺肿瘤 放射疗法 正电子发射断层摄影术 X线计算机体层摄影术 靶区勾画 |
| 英文关键词:Lung neoplasms Radiotherapy Positron emission tomography X-ray computed tomography Target volume delineation |
| 基金项目: |
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| 摘要点击次数: 2806 |
| 全文下载次数: 1994 |
| 中文摘要: |
| 目的 研究肺癌放射治疗中应用PET-CT定位时不同靶区勾画方式对靶区体积以及正常组织受量的影响。方法选择2例肺癌患者。扫描后进行图像融合,并根据不同阈值勾画靶区并设计治疗计划,比较各个靶区大小以及正常组织受量。勾画靶区时采用的3个阈值分别为Kmax(50%)、Kmax(40%)和SUV2.5。Kmax(50%)和Kmax(40%)分别是最大单位体积摄取值的50%和40%,SUV2.5是标准摄取值2.5。根据上述特定阈值勾画大体肿瘤体积(GTV),考虑到器官运动和摆位误差,在GTV基础上外放1.5cm作为计划靶体积(PTV)。勾画的正常组织包括肺和脊髓,并用剂量体积直方图加以比较。结果3个阈值勾画的结果不同,2例患者GTV分别为23.1、34.9、49.2 cm3和58.1、80.3、163.4cm3,PTV分别为169.5、222.1、261.9cm3和286.8、349.7、560.5cm3;全肺受量超过20Gy的体积分别为14.4%、17.2%、19.5%和15.2%、16.0%、20.2%,全肺平均剂量分别占16.2%、19.4%、21.4%和12.7%、14.4%、19.4%。≤1cm3脊髓的受量分别占30.6%、34.3%、44.9%和27.3%、35.2%、67.1%。结论应用PET-CT定位时采用不同靶区勾画方式对GTV、PTV和正常组织受量影响很大。在正常组织能够耐受情况下,应考虑采用靶区覆盖较好的阈值勾画靶区。 |
| 英文摘要: |
| Objective To investigate the effect of target volume and normal tissues dose in lung cancer patients with PET-CT of different delineation methods. Methods Two patients were chosen. After PET-CT scan, the images were transferred to the radiotherapy planning system (Varian Eclipse) for images fusion and treatment planning design. The three gross tumor volumes (GTVs) were defined using a threshold value of 50% of Kmax of the whole lesion(GTV50), a threshold value of 40% of Kmax of the whole lesion (GTV40) and a threshold value of SUV=2.5 (GTV2.5), respectively. The Kmax was the maximum voxel value of PET activity (Bq/ml). The planning target volumes (PTVs) were obtained by addition of an 1.5cm around the GTV. The normal tissues were defined, including the total lung and spinal cord. Dose distribution was computed for the other two PTVs. Plans were compared using dose volume histograms for lung and spinal cord.Results The results of three methods were different in two patients. The GTVs were 23.1,34.9,49.2 cm3 and 58.1,80.3,163.4 cm3, respectively. The PTVs were 169.5, 222.1, 261.9 cm3 and 286.8,349.7,560.5 cm3, respectively. The percentages of whole lung that received a dose of 20 Gy or more were 14.4%,17.2%,19.5% and 15.2%,16.0%, 20.2%,respectively. The mean lung dose were 16.2%,19.4%,21.4% and 12.7%,4.4%,19.4%. The doses of ≤1 cm3 spinal cord were 30.6%,34.3%,44.9% and 27.3%,35.2%,67.1%.Conclusions The effect of target volume and normal tissues dose in lung cancer patients with PET-CT of different delineation methods were significant. The threshold value that can cover tumor more completely should be used to define target volumes for radiotherapy when the normal tissues can accepted tolerance dose. |
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