| Photon energies between6-and15-MV are typically used for the radiotherapy ofhepatic malignant tumors three methods are adopted which is3-DCRT, IMRT, VMAT(RapidArc), Rigonal radiation with high dose distrubution can improve tumor localcontrol rate, prolonged the survival, Some finished study on hepatic malignant tumorsare found about research on dosimetric effect of RapidArc and IMRT, on treatment ofThoracic tumor with6and18MV Photon energies. The results show that there is noobvious difference between PTV coverage and tolerance dose of organ at risk, butRapidArc plan comparison of multiple hepatic tumor with6and15MV Photonenergies have not been foundHere12patients,6-and15-MV RapidArc planning with single and double358°arcwas performed using identical planning objectives and dose constraints respectively.Four kinds of plans compared according to dose–volume histogram (DVH) analysisincluding conformity and homogeneity index (CI and HI), considering also magnitudeand location of planning target volumes (PTVs).The results show that: all of the plans can meet the clinical requirement. nostatistically significant differences between6-and15-MV RapidArc plans wereobserved in the CI, HI, the maximum dose and the minimum dose of PTV, and all theCI can get to0.91and HI to0.88. In the RapidArc plans with two358o arcs, theV5,V10,V15of normal liver were higher than that of single arc, while V20, V25, V30, V35,V40were lower than that of single arc. The value of V5to V40of normal liver, radiationdose of stomach, duodenum and spinal cord differed no significantly among these plans.Though high energy photon beams have typical characteristics of lower entry doses,high depth dose penetration and high gradient dose distribution, the resulting neutroncontamination of photon energy higher of10MV can induce Secondary malignantneoplasm, which have been documented by more than one studies6MV RapidArc with single or two whole358o arcs. would be selected chiefly in theradiotherapy of multiple haptic tumor... |
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