Using three dimensional treatment planning system,to assess the dosimetric of different radiation therapy planning and obtain a better technique in the treatment of non- small cell lung cancer. Methods Using the Topslane treatment planning system,thirty pathologically proved patients of non-small cell lung cancer were chosen in this study. Four different methods of radiotherapy planning were used for each case, conventional radiation, conventional plus conformal radiation, elective nodal irradiation (ENI) and involved-field irradiation (IFI). The total radiation dose was 66 Gy. Dose volume histogram(DVH), nomal tissue complication probability(NTCP), tumor control probability (TCP) and conformity index (CI) were used to assess the target volume dosimetric distribution and nomal tissue complication probability. Results TCP of conventional radiation，conventional plus conformal radiation ，ENI and IFI groups were 94.7％、96.9％、97.1％、97.5％; CI were 0.09、0.15、0.21、0.27, respectively; the total lung volume received radiation 20 Gy(V20)were 25.7％、25.1％、23.6％、21.8％; NTCP were 7.8％、7.9％、6.8％、5.6％, respectively.The total esophageal volume received radiation 45Gy(V45) were 31.3％、31.0％、23.2％、19.7％. The maximum dose at the heart were 64.3Gy、62.4Gy、58.9Gy、54.1Gy, the mean dose were 25.7Gy、24.7Gy、15.1Gy、14.3Gy. The maximum dose at the spinal cord were 42.6Gy、42.1Gy、39.4Gy、38.4Gy. Conclusions As compared with the conventional radiotherapy, 3DCRT increases the dose at target and TCP, and decreases the dose at the normal tissue、NTCP. IFI can protect normal tissue effectively, which make it possiple to increase the dose at target and TCP. IFI should be the best way in the radiotherapy of non-small cell lung cancer.
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