A finger leaf design for dual layer MLCs

VernacularTitle:用于双层多叶准直器的指形叶片设计
Author: Weijie CUI ; Jianrong DAI
Publication Type:Journal Article
Keywords: Finger leaf; Dual layer MLC; Field conformity
From: Chinese Journal of Radiological Medicine and Protection 2010;30(1):29-32
CountryChina
Language:Chinese
Abstract: Objective To introduce a finger leaf design that is applied to dual layer MLCs.Methods An optimization model was firstly constructed to describe the problem of determining leaf end shapes,and the corresponding problems were then solved by the simplex search method or the simulated annealing technique.Optimal parameters for arc shapes of leaf end projections were obtained,and a comparison was done between optimized MLCs and conventional MLCs in terms of field conformity.The optimization process was based on 634 target fields selected from the patient data base of a treatment planning system.Areas of these fields ranged from 20.0 to 602.7 cm with a mean and its standard deviation of (125.7 ±0.0) cm~2.Results The optimized leaf end shapes projected to the isocenter plane were semicircles.With the finger leaf design,the total area of discrepancy regions between MLC fields and target fields was reduced by 32.3% .Conclusions The finger leaf design improves the conformity of the MLC shaped fields to the desired target fields.