论文部分内容阅读
AIM:To compare intensity-modulated radiotherapy (IMRT)with conformal radiotherapy (CRT) by investigating the doseprofiles of primary tumors,electively treated regions,andthe doses to organs at risk.METHODS:CRT and IMRT plans were designed for fivepatients with upper esophageal carcinoma.For each patient,target volumes for primary lesions (67.2 Gy) and electivelytreated regions (50.4 Gy) were predefined.An experiencedplanner manually designed one CRT plan.Four IMRT planswere generated with the same dose-volume constraints,butwith different beam arrangements.Indices including dosedistributions,dose volume histograms (DVHs) and conformityindex were compared.RESULTS:The plans with three intensity-modulated beamswere discarded because the doses to spinal cord were lagerthan the tolerable dose 45Gy,and the dose on areas nearthe skin was up to 50Gy.When the number of intensitybeams increased to five,IMRT plans were better than CRTplans in terms of the dose conformity and homogeneity oftargets and the dose to OARs.The dose distributions changedlittle when the beam number increased from five to sevenand nine.CONCLUSION:IMRT is superior to CRT for the treatmentof upper esophageal carcinoma with simultaneous integratedboost (SIB).Five equispaced coplanar intensity-modulatedbeams can produce desirable dose distributions.The primarytumor can get higher equivalent dose by SIB technique.The SIB-IMRT technique shortens the total treatment time,and is an easier,more efficient,and perhaps a less error-prone way in delivering IMRT.
AIM: To compare intensity-modulated radiotherapy (IMRT) with conformal radiotherapy (CRT) by investigating the dose profiles of primary tumors, electively treated regions, and the doses to organs at risk. METHODS: CRT and IMRT plans were designed for fivepatients with upper esophageal carcinoma .For each patient, target volumes for primary lesions (67.2 Gy) and electively -treated regions (50.4 Gy) were pre-defined .An experienced planner manually designed one CRT plan. Four IMRT planswere generated with the same dose-volume constraints, but with different beam arrangements. Indices including dosedistributions, dose volume histograms (DVHs) and conformityindex were compared .RESULTS: The plans with three intensity-modulated beamswere discarded because of doses to spinal cord were lagerthan the tolerable dose 45Gy, and the dose on areas nearthe skin was up to 50Gy. When the number of intensity increases to five, IMRT plans were better than CRTplans in terms of the dose conformity and homogeneity oftargets and the dose to OARs. The dose distributions changedlittle when the beam number increased from five to seven and nine. CONCLUSION: IMRT is superior to CRT for the treatment of upper esophageal carcinoma with simultaneous integrated boost (SIB) .FIVE equispaced coplanar intensity-modulatedbeams can be desirable dose distribution. The primary tumor can get higher equivalent dose by SIB technique. The SIB-IMRT technique shortens the total treatment time, and is an easier, more efficient, and perhaps a less error-prone way in delivering IMRT.