A dynamic blood flow model to compute absorbed dose to circulating blood and lymphocytes in liver external beam radiotherapy.
A dynamic blood flow model to compute absorbed dose to circulating blood and lymphocytes in liver external beam radiotherapy.
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DOI：
10.1088/1361-6560/ac4da4
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发表时间：
2022-02-15
影响因子：
3.5
通讯作者：
Paganetti H
中科院分区：
文献类型：
--
作者：
Xing S;Shin J;Pursley J;Correa-Alfonso CM;Depauw N;Domal S;Withrow J;Bolch W;Grassberger C;Paganetti H
我们已经开发了一种新的4D动态肝脏血流模型，能够准确估计剂量循环血细胞在肝脏定向外照射放疗，占血液再循环和辐射输送时间结构。开发了具有详细血管树的成年男性和成年女性肝脏计算模型，以包括肝动脉、肝门静脉和肝静脉树。基于心输出量和器官血容量的参考值，应用离散时间马尔可夫链方法来确定人体中105个血液颗粒（BP）的时空分布。对于进入肝脏的BP，实施了显式Monte Carlo模拟，以跟踪其沿沿着~2000个不同的血管通路通过肝脏的传播。该模型以0.1s的时间分辨率跟踪来自时间依赖性辐射场的累积吸收剂量。然后对接受光子（VMAT和IMRT）和质子（被动SOBP和主动PBS）治疗的3名男性和3名女性患者的计算模型进行评价。使用平均剂量（X射线剂量，B）、V> 0 Gy、V> 0.125 Gy和D2%研究和量化治疗方式、输送时间和分次对循环血细胞的剂量学影响。与光子处理相比，质子处理的γ射线剂量、B、V> 0 Gy、V>0.125Gy和D2%分别平均减少45%、6%、53%和19%。我们的模拟还表明，V> 0 Gy，V>0.125Gy和D2%对束流开启时间高度敏感。V> 0 Gy和V>0.125Gy都随着射束开启时间的增加而增加，而D2%随着射束开启时间的增加而减少，这表明低剂量对大部分血细胞和高剂量对小部分血细胞之间的权衡。因此，仅基于积分剂量考虑，质子治疗在血液剂量方面不一定有利。相反，积分剂量和射束开启时间都可以显著影响相关的剂量测定指数。
We have developed a novel 4D dynamic liver blood flow model, capable of accurate dose estimation to circulating blood cells during liver-directed external beam radiotherapy, accounting for blood recirculation and radiation delivery time structure. Adult male and adult female liver computational phantoms with detailed vascular trees were developed to include the hepatic arterial, hepatic portal venous, and hepatic venous trees. A discrete time Markov Chain approach was applied to determine the spatiotemporal distribution of 105 blood particles (BP) in the human body based on reference values for cardiac output and organ blood volumes. For BPs entering the liver, an explicit Monte Carlo simulation was implemented to track their propagation along ~2000 distinct vascular pathways through the liver. The model tracks accumulated absorbed dose from time-dependent radiation fields with a 0.1s time resolution. The computational model was then evaluated for 3 male and 3 female patients receiving photon (VMAT and IMRT) and proton (passive SOBP and active PBS) treatments. The dosimetric impact of treatment modality, delivery time, and fractionation on circulating blood cells was investigated and quantified using the mean dose (𝜇dose,,b), V>0Gy, V>0.125Gy, and D2%. Average reductions in 𝜇dose,b, V>0Gy, V>0.125Gy and D2% of 45%, 6%, 53%, 19% respectively, were observed for proton treatments as compared to photon treatments. Our simulation also showed that V>0Gy, V>0.125Gy, and D2% were highly sensitive to the beam-on time. Both V>0Gy and V>0.125Gy increased with beam-on time, whereas D2% decreased with increasing beam-on time, demonstrating the tradeoff between low dose to a large fraction of blood cells and high dose to a small fraction of blood cells. Consequently, proton treatments are not necessarily advantageous in terms of dose to the blood simply based on integral dose considerations. Instead, both integral dose and beam-on time can substantially impact relevant dosimetric indices.
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影响因子：
2.3
作者：
Ko EC;Benjamin KT;Formenti SC
通讯作者：
Formenti SC
DOI：
10.1085/jgp.9.6.835
发表时间：
1926-07-20
期刊：
The Journal of general physiology
影响因子：
--
作者：
Murray CD
通讯作者：
Murray CD
影响因子：
1.7
作者：
Fang P;Shiraishi Y;Verma V;Jiang W;Song J;Hobbs BP;Lin SH
通讯作者：
Lin SH
影响因子：
3.5
作者：
Hammi A;Paganetti H;Grassberger C
通讯作者：
Grassberger C
影响因子：
2.4
作者：
Debbaut, Charlotte;Segers, Patrick;Monbaliu, Diethard
通讯作者：
Monbaliu, Diethard