南华大学学报：自然科学版
南華大學學報：自然科學版
남화대학학보：자연과학판
Journal of University of South China(Science and Technology)
2011年
4期
29-34
,共6页
张彦秋%邱小平%杨振%吕知平
張彥鞦%邱小平%楊振%呂知平
장언추%구소평%양진%려지평
各向异性分析算法%蒙特卡罗模拟%骨介质%精度评估
各嚮異性分析算法%矇特卡囉模擬%骨介質%精度評估
각향이성분석산법%몽특잡라모의%골개질%정도평고
Anisotropic Analytical Algorithm%Monte Carlo simulation%bone%accuracy evaluation
用蒙特卡罗模拟评估放射治疗剂量计算使用的各向异性分析算法（Aniso-tropic Analytical Algorithm,AAA）在小野条件下骨介质中的计算精度.建立一包含骨介质的水模体,分别用AAA算法、PBC算法（作为对比）和蒙特卡罗（Monte Carlo,MC）模拟计算2 cm×2 cm到8 cm×8 cm射野条件下该模体中的深度剂量和离轴比,并以MC模拟为标准比较深度剂量,用一维伽马分析对离轴比进行分析.结果显示,与MC模拟的结果相比,AAA算法与PBC算法均高估了骨介质区域的剂量,高估的剂量偏差范围分别为2.16%～2.7%、1.4%～2.03%.AAA算法与PBC算法均低估了（PBC算法2 cm×2 cm射野除外）肺介质后区域的剂量,低估的剂量偏差范围分别为-0.39%～-1.19%、-0.13%～-0.4%.AAA算法和PBC算法分别略高估了射野内边缘和外边缘的剂量.一维伽马分析显示AAA算法和PBC算法（以MC模拟结果为基准）在2 cm×2 cm到8 cm×8 cm射野,通过率分别为100%、100%1、00%、86%,100%、100%、72%、64%.总之,AAA算法在骨介质中剂量计算的结果略高于MC模拟的结果,与PBC算法相比,计算精度没有显示出明显的优势.
用矇特卡囉模擬評估放射治療劑量計算使用的各嚮異性分析算法（Aniso-tropic Analytical Algorithm,AAA）在小野條件下骨介質中的計算精度.建立一包含骨介質的水模體,分彆用AAA算法、PBC算法（作為對比）和矇特卡囉（Monte Carlo,MC）模擬計算2 cm×2 cm到8 cm×8 cm射野條件下該模體中的深度劑量和離軸比,併以MC模擬為標準比較深度劑量,用一維伽馬分析對離軸比進行分析.結果顯示,與MC模擬的結果相比,AAA算法與PBC算法均高估瞭骨介質區域的劑量,高估的劑量偏差範圍分彆為2.16%～2.7%、1.4%～2.03%.AAA算法與PBC算法均低估瞭（PBC算法2 cm×2 cm射野除外）肺介質後區域的劑量,低估的劑量偏差範圍分彆為-0.39%～-1.19%、-0.13%～-0.4%.AAA算法和PBC算法分彆略高估瞭射野內邊緣和外邊緣的劑量.一維伽馬分析顯示AAA算法和PBC算法（以MC模擬結果為基準）在2 cm×2 cm到8 cm×8 cm射野,通過率分彆為100%、100%1、00%、86%,100%、100%、72%、64%.總之,AAA算法在骨介質中劑量計算的結果略高于MC模擬的結果,與PBC算法相比,計算精度沒有顯示齣明顯的優勢.
용몽특잡라모의평고방사치료제량계산사용적각향이성분석산법（Aniso-tropic Analytical Algorithm,AAA）재소야조건하골개질중적계산정도.건립일포함골개질적수모체,분별용AAA산법、PBC산법（작위대비）화몽특잡라（Monte Carlo,MC）모의계산2 cm×2 cm도8 cm×8 cm사야조건하해모체중적심도제량화리축비,병이MC모의위표준비교심도제량,용일유가마분석대리축비진행분석.결과현시,여MC모의적결과상비,AAA산법여PBC산법균고고료골개질구역적제량,고고적제량편차범위분별위2.16%～2.7%、1.4%～2.03%.AAA산법여PBC산법균저고료（PBC산법2 cm×2 cm사야제외）폐개질후구역적제량,저고적제량편차범위분별위-0.39%～-1.19%、-0.13%～-0.4%.AAA산법화PBC산법분별략고고료사야내변연화외변연적제량.일유가마분석현시AAA산법화PBC산법（이MC모의결과위기준）재2 cm×2 cm도8 cm×8 cm사야,통과솔분별위100%、100%1、00%、86%,100%、100%、72%、64%.총지,AAA산법재골개질중제량계산적결과략고우MC모의적결과,여PBC산법상비,계산정도몰유현시출명현적우세.
In order to evaluate the calculation accuracy of Anisotropic Analytical Algorithm（AAA）for the situation with small fields in a water-bone phantom using Monte Carlo simu-lation as benchmarks.A water phantom with a bone slab was built,in which the depth dose（DD） and off-axis ratio（OAR） for field 2 cm×2 cm to field 8 cm×8 cm were calculated by AAA algorithms,PBC algorithms（as comparison）,and Monte Carlo（MC） simulation.The evaluation of algorithms by MC simulation was achieved by the comparisons of DD and the 1 dimension gamma analysis of OAR.It was shown that both of AAA algorithm and PBC algorithm overestimated the DD in bone region,and the dose differences ranged from 2.16%～2.7%,1.4%～2.03%,respectively.AAA algorithm and PBC algorithm underestimated the DD in back of bone region,and the dose differences ranged from-0.39%～-1.19%,-0.13%～-0.4%,respectively.AAA algorithm and PBC algorithm overestimated the dose of field inner edge and field outer edge,respectively.One dimension gamma analysis indicated that AAA algorithm and PBC algorithm gamma pass rate was 100%,100%,100%,86%,100%,100%,72%,64%,respectively.In bone medium,the dose calculated by AAA was slightly higher than MC simulation,the calculation accuracy was not evidently higher than PBC.
