中华放射肿瘤学杂志
中華放射腫瘤學雜誌
중화방사종류학잡지
CHINESE JOURNAL OF RADIATION ONCOLOGY
2012年
1期
72-76
,共5页
赵艳群%王培%黎杰%肖明勇%郎锦义%吴大可
趙豔群%王培%黎傑%肖明勇%郎錦義%吳大可
조염군%왕배%려걸%초명용%랑금의%오대가
筒串卷积算法%笔形束卷积算法%蒙特卡罗算法%非均匀组织模体
筒串捲積算法%筆形束捲積算法%矇特卡囉算法%非均勻組織模體
통천권적산법%필형속권적산법%몽특잡라산법%비균균조직모체
Collapsed cone convolution algorithm%Pencil beam convolution algorithm%Monte Carlo algorithm%Heterogeneous tissue phantom
目的 比较治疗计划系统(TPS)中光子束剂量的筒串卷积算法(CCC)与笔形束卷积算法(PBC)在非均匀组织中的计算精确度.方法 建立2个虚拟肺模型,一个在光子束单前野入射情况下比较两种算法得到的中心轴上的百分深度剂量(PDD)；另一个在光子束前后对穿野入射,模体中心有一个肿瘤等效组织,两种算法计算光子束穿过肺等效组织到达肿瘤等效组织时肺和肿瘤等效组织中的剂量分布.两种情况下得到的结果与蒙特卡罗(MC)算法计算的结果进行比较.结果 单前野时,光子束从高密度组织入射到低密度的肺等效组织,与MC算法比较PBC算法高估了肺等效组织中的剂量(t=3.90,P=0.012),CCC算法与之接近(t=2.25,P=0.087).前后对穿野时,CCC算法和MC算法计算出的肿瘤等效组织边界剂量都要低于PBC算法的剂量(t=2.43、3.18,P=0.038、0.011),并且能量越高,肺密度越小时,这种差别越大.结论 计算低密度组织中的肿瘤或其后方肿瘤剂量时最好采用CCC算法(如肺癌、食管癌以及胀气的直肠和胃后方肿瘤).
目的 比較治療計劃繫統(TPS)中光子束劑量的筒串捲積算法(CCC)與筆形束捲積算法(PBC)在非均勻組織中的計算精確度.方法 建立2箇虛擬肺模型,一箇在光子束單前野入射情況下比較兩種算法得到的中心軸上的百分深度劑量(PDD)；另一箇在光子束前後對穿野入射,模體中心有一箇腫瘤等效組織,兩種算法計算光子束穿過肺等效組織到達腫瘤等效組織時肺和腫瘤等效組織中的劑量分佈.兩種情況下得到的結果與矇特卡囉(MC)算法計算的結果進行比較.結果 單前野時,光子束從高密度組織入射到低密度的肺等效組織,與MC算法比較PBC算法高估瞭肺等效組織中的劑量(t=3.90,P=0.012),CCC算法與之接近(t=2.25,P=0.087).前後對穿野時,CCC算法和MC算法計算齣的腫瘤等效組織邊界劑量都要低于PBC算法的劑量(t=2.43、3.18,P=0.038、0.011),併且能量越高,肺密度越小時,這種差彆越大.結論 計算低密度組織中的腫瘤或其後方腫瘤劑量時最好採用CCC算法(如肺癌、食管癌以及脹氣的直腸和胃後方腫瘤).
목적 비교치료계화계통(TPS)중광자속제량적통천권적산법(CCC)여필형속권적산법(PBC)재비균균조직중적계산정학도.방법 건립2개허의폐모형,일개재광자속단전야입사정황하비교량충산법득도적중심축상적백분심도제량(PDD)；령일개재광자속전후대천야입사,모체중심유일개종류등효조직,량충산법계산광자속천과폐등효조직도체종류등효조직시폐화종류등효조직중적제량분포.량충정황하득도적결과여몽특잡라(MC)산법계산적결과진행비교.결과 단전야시,광자속종고밀도조직입사도저밀도적폐등효조직,여MC산법비교PBC산법고고료폐등효조직중적제량(t=3.90,P=0.012),CCC산법여지접근(t=2.25,P=0.087).전후대천야시,CCC산법화MC산법계산출적종류등효조직변계제량도요저우PBC산법적제량(t=2.43、3.18,P=0.038、0.011),병차능량월고,폐밀도월소시,저충차별월대.결론 계산저밀도조직중적종류혹기후방종류제량시최호채용CCC산법(여폐암、식관암이급창기적직장화위후방종류).
Objective To compare the calculation precision of the collapsed cone convolution (CCC) algorithm and pencil beam convolution (PBC) algorithm in TPS in heterogeneous tissue.Methods We made two virtual lung phantoms,one is single field phantom,In this case the photon beam incident into the phantom,the other is the two fields phantom and a cubic'tumor' was placed in the centre of the phantom.two opposite photon beams incident into the phantom.We calculated the dose of the'tumor' and the lung with the CCC and PBC algorithm.We compared the results in both case with if obtained from Monte Carlo (MC) method.Results In the single field phantom,the photon beam incident from the high-density tissue to the low-density lung equivalent tissue,compared with the result of MC algorithm PBC algorithm overestimated the lung equivalent tissue dose (t =3.90,P =0.012) and the result of CCC algorithm is close to it ( t =2.25,P =0.087 ).In the two fields phantom,tumor boundary dose calculated by CCC algorithm and the MC algorithm are lower than that of the PBC algorithm (t =2.43,3.18,P =0.038,0.011 ),and the difference increase when the field size decrease, the beam energy increase and the density of the inhomogeneity decrease.Conclusions We had better use the CCC algorithm when calculating the dose of the tumor surrounded by low-density tissue or the tumor behind the low-density tissue,such as the lung cancer,esophageal cancer etc.
