Comparison Of IMRT, 3DCRT And RT In Dosimetry Of Esophageal Cancer Radiotherapy

Objective: The aim of this study is to evaluate three radiotherapy plannings of esophageal cancer radiotherapy with 3D-treatment planning system, to compare IMRT, 3DCRT, and RT planning in dose of target volume and protection of normal important tissues, and to obtain which technique is better. Methods: For the 21 esophageal cancer patients three plannings were done with CadPlan 6.4.7 3D-treatment system. The prescription dose was 50 Gy. The differences of target dose and normal tissue dose were compared with DVH. Result: The dose received by 95% GTV volume of RT, 3DCRT and IMRT were 47.46±2.02Gy,48.12± 0.78Gy and 49.20 ± 0.37Gy respectively. IMRT was best (P<0.01). The dose received by 95% PTV volume of three planning were 30.07±7.74Gy, 45.44±1.35Gy and 47.98±1.39Gy respectively. 3DCRT and IMRT was better than RT (P<0.01). The value of conformity index(CI) of three planning were 0.38 ± 0.19, 0.74±0.14 and 0.95±0.07 respectively. The CI of IMRT is best(P<0.01). The volume of lung of three planning which received radiation dose of≥20Gy (V₂₀) were 21.63 ± 6.26)%, (35.81 ± 13.21)% and (32.95± 10.93)%. 3DCRT and IMRT enhanced V₂₀ than RT (P<0.01). The dose at 5% spinal cord volume were 21.99 ± 6.41Gy, 16.42 ± 5.11 Gy and 21.25 ± 5.42 Gy and the radiation dose received by 30% heart volume were 19.32 ±11.02Gy, 18.40±11.33Gy and 20.37± 11.73Gy respectively. Conclusion: IMRT and 3DCRT are better to RT in conformity index and dose of target volume. The differences of dose received by normal tissues are not significant, and there are all in thescope which normal tissue can endure. IMRT is better to 3DCRT in conformity index of target volume, but the others are not significant different.