| Purpose: To evaluate the different dosimetric results of RapidArc andIMRT for malignant gliomas, and provide a reference for selection betweendifferent radiotherapy techniques.Methods: Twenty patients with malignant gliomas who were treated in theour department of radiotherapy were selected for study. Every patient wascarried out for two kinds of treatment planning,one with2arc-RapidArctechnique,while the other with5f-IMRT technique. Studying the dosedistribution of target volume and protection of organs at risk by dose volumehistogram (DVH) and plan dose (PD).We compared the dose distribution oftarget (HI, CI, Dmean,D95%and D5%),organs at risk (Dmean, D1%,V30andV40) between the two techniques．Results:1Dose distribution of target volume:(1)Considering PTV1,2arc-RapidArc was better than5f-IMRT in D95%and CI (P <0.05), but nosignificant difference was found in Dmean, D5%and HI between2arc-RapidArc and5f-IMRT.(2) Considering PTV2,2arc-RapidArc was betterthan5f-IMRT in Dmean,D95%and CI (P <0.05),5f-IMRT was better inHI(P <0.05), but in D5%between2arc-RapidArc and5f-IMRT we didn’t findany significant difference.2Protection of organs at risk:(1)2arc-RapidArc wasbetter than5f-IMRT in the protection of optic nerve and healthy brain (P <0.05). Compared with5f-IMRT,2arc-RapidArc’s Dmean of brainstem, opticnerve, optic chiasm, lens and pituitary was a little lower,while that of inner earand healthy brain was higher, but the differences were not statisticallysignificant. The doses that OARs received were all less than the safety doselimits.3Treatment time and Monitor units： Compared with5f-IMRT, 2arc-RapidArc took significantly less treatment time and monitor units.Conclusion: Both2arc-RapidArc and5f-IMRT techniques can satisfy therequirement of clinic dosimetry, dosimetry coverage of the target volume andhomogeneity very well, but2arc-RapidArc has better conformity and lowerdose of organs at risk than the5f-IMRT. What’s more,2arc-RapidArc takesless treatment time and monitor units. |
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