基于模拟退火法的医用电子加速器6MV X 射线能谱重建

doi:10.3969/j.issn.0258-8021. 2013. 04.01

摘要
图/表
参考文献
相关文章 (1)

全文: PDF (276 KB) HTML (1 KB)
输出: BibTeX | EndNote (RIS)

摘要根据测量的中轴百分深度剂量（PDD）以及MonteCarlo模拟的单能光子PDD，研究基于模拟退火(SA)算法重建医用电子加速器6MV X射线能谱的方法。在优化过程中，选择60个能量间隔，对应不同的相对权重，选择目标函数为重建PDD（即各相对权重与MonteCarlo模拟单能光子PDD的乘积）与实测PDD之间的相关系数，运用模拟退火进行优化得到的最优解就是加速器的能谱。为了验证算法的有效性，对加速器治疗头进行Monte-Carlo模拟，得到从治疗头出射的6 MV光子能谱。实验结果表明，计算能谱与Monte-Carlo模拟能谱在能谱形状、峰值能量方面一致；同时，根据重建能谱获得的PDD与实测PDD保持高度一致，均方根误差为1.56×10^-4。上述实验结果表明，基于模拟退火算法重建光子能谱有效可靠。

	服务

	把本文推荐给朋友
	加入我的书架
	加入引用管理器
	E-mail Alert
	RSS
	作者相关文章
	刘娟周正东^* 陈元华王东东

关键词 ：模拟退火, Monte-Carlo模拟, X射线能谱, 百分深度剂量

Abstract：A method based on simulated annealing (SA) algorithm to reconstruct 6MV X-ray energy spectra from medical linear accelerators was investigated in this work, utilizing both measured percentage depth doses (PDD) and MonteCarlo simulated central axis PDD of monoenergy photons. As for the SA optimization, 60 energy bins were employed with different relative weights and the objective function was chosen as the correlation coefficient between reconstructed PDD (the products of relative weights and Monte-Carlo simulated PDD) and measured PDD. The optimal solution calculated by SA algorithm was exactly the spectrum of the accelerator. To verify the proposed method, a Monte-Carlo simulation of the accelerator treatment head was performed to calculate the 6MV photon energy spectrum for comparison. Results showed that the reconstructed spectrum was in good agreement with the MonteCarlo simulated spectrum in both shape and peak position; the derived PDD from reconstructed spectrum were highly consistent with the measured PDD with a rootmeansquare error of 1.56×10^-4. Above experimental results indicated that reconstructing photon spectra based on SA algorithm with measured PDD was effective and reliable.

Key words： simulated annealing Monte-Carlo simulation X-ray spectra percentage depth dose

引用本文:

刘娟周正东^* 陈元华王东东. 基于模拟退火法的医用电子加速器6MV X 射线能谱重建[J]. 中国生物医学工程学报, 2013, 32(4): 385-389.
LIU Juan ZHOU Zheng Dong^*CHEN Yuan Hua WANG Dong Dong. Reconstruction of 6MV Xray Spectra of Medical Linear Accelerator Based on Simulated Annealing Algorithm. journal1, 2013, 32(4): 385-389.

链接本文:

http://cjbme.csbme.org/CN/10.3969/j.issn.0258-8021. 2013. 04.01 或 http://cjbme.csbme.org/CN/Y2013/V32/I4/385

［1］Deng J, Jiang SB, Kapur A, et al. Photon beam characterization and modeling for Monte Carlo treatment planning ［J］. Physics in Medicine and Biology, 2000, 45: 411-427.［2］王妙琪.利用蒙地卡罗法模拟西门子医用直线加速器输出之光子射束特性［D］. 台湾: 国立阳明大学，2009.
［3］张松柏，黄斐增，韩树奎，等. 6MV医用电子直线加速器轫致辐射谱研究［J］. 原子能科学技术, 2003, 37(3): 206-210.
［4］Baker CR，Peck KK. Reconstruction of 6 MV photon spectra from measured transmission including maximum energy estimation ［J］. Physics in Medicine and Biology, 1997, 42: 2041-2051.
［5］王毅，李勤，江孝国，等. 衰减透射法测量高能X射线能谱［J］. 强激光与粒子束, 2012, 6:1466-1470.
［6］Deng J，Jiang SB，Pawlicki T, et al. Derivation of electron and photon energy spectra from electron beam central axis depth dose curves ［J］. Physics in Medicine and Biology, 2001, 46: 1429-1449.
［7］姚杏红，黄斐增，吴昊，等. 利用深度剂量数据重建放射治疗X射线能谱［J］. 原子能科学技术, 2010, 44(4): 464-468.
［8］Bloch P, Altschuler MD, Bjarngard BE, et al. Determining clinical photon beam spectra from measured depth dose with the Cimmino algorithm ［J］. Physics in Medicine and Biology, 2000, 45: 171-183.
［9］Carletti C, Meoli P, Craero WR. A modied simulated annealing algorithm for parameter determination for a hybrid virtual model ［J］. Physics in Medicine and Biology, 2006, 51: 3941-3952.
［10］周正东，陈元华，刘娟. 基于遗传算法的医用直线加速器光子能谱重建方法［J］. 东南大学学报：自然科学版, 2012, 42(6):1085-1088.
［11］赵继俊. 优化技术与MATLAB优化工具箱［M］. 北京: 机械工业出版社, 2011.
［12］蒋金山, 何春雄, 潘少华. 最优化计算方法［M］. 广州: 华南理工大学出版社, 2007.