Oxygen consumption dynamics in steady-state tumour models.
Oxygen consumption dynamics in steady-state tumour models.
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DOI：
10.1098/rsos.140080
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发表时间：
2014-09
影响因子：
3.5
通讯作者：
Partridge M
中科院分区：
文献类型：
--
作者：
Grimes DR;Fletcher AG;Partridge M
癌症组织中的氧气水平可以对治疗反应产生重大影响：低氧组织比氧气充足的组织更耐辐射，更耐化疗。虽然医学成像的最新进展促进了对宏观氧合作用的实时观察，但潜在的物理学将分辨率限制在毫米级，而氧气压力在微米级上变化。如果能够准确地估计氧在肿瘤微环境中的分布，那么就可以更好地模拟潜在剂量增加对这些缺氧区的影响，从而能够更真实地模拟生物适应性治疗。反应扩散模型常被用来模拟氧气动力学，假定氧消耗率(OCR)依赖于细胞状态和局部氧气供应的各种函数形式。在这项工作中，我们考察了球对称几何和柱对称几何中氧气消耗的反应扩散模型。我们考虑了两种不同的耗氧量描述：一种是耗氧率不变，另一种是耗氧率随氧分压以双曲线形式变化。在每种情况下，我们都得到了稳态氧分布的解析近似，结果表明它与方程的数值解非常接近，并准确地预测了氧可以扩散的程度。推导出的表达将氧气可以扩散到组织中的极限与该组织的OCR联系起来。我们还证明了这些泛函形式之间的差异在文献估计的双曲氧常数范围内很可能是可以忽略的，这表明恒耗速率近似足以模拟大多数OCR值的氧动力学。这些近似还允许快速识别双曲线消耗形式可能导致与恒定消耗速率模型显著不同的情况，从而通过估计氧扩散距离和合成的氧分布来减少与数值解相关的计算工作量。这样的分析可能对大型成像数据集和组织切片中的参数拟合有用，并允许轻松量化OCR功能形式之间的投影差异。
Oxygen levels in cancerous tissue can have a significant effect on treatment response: hypoxic tissue is both more radioresistant and more chemoresistant than well-oxygenated tissue. While recent advances in medical imaging have facilitated real-time observation of macroscopic oxygenation, the underlying physics limits the resolution to the millimetre domain, whereas oxygen tension varies over a micrometre scale. If the distribution of oxygen in the tumour micro-environment can be accurately estimated, then the effect of potential dose escalation to these hypoxic regions could be better modelled, allowing more realistic simulation of biologically adaptive treatments. Reaction–diffusion models are commonly used for modelling oxygen dynamics, with a variety of functional forms assumed for the dependence of oxygen consumption rate (OCR) on cellular status and local oxygen availability. In this work, we examine reaction–diffusion models of oxygen consumption in spherically and cylindrically symmetric geometries. We consider two different descriptions of oxygen consumption: one in which the rate of consumption is constant and one in which it varies with oxygen tension in a hyperbolic manner. In each case, we derive analytic approximations to the steady-state oxygen distribution, which are shown to closely match the numerical solutions of the equations and accurately predict the extent to which oxygen can diffuse. The derived expressions relate the limit to which oxygen can diffuse into a tissue to the OCR of that tissue. We also demonstrate that differences between these functional forms are likely to be negligible within the range of literature estimates of the hyperbolic oxygen constant, suggesting that the constant consumption rate approximation suffices for modelling oxygen dynamics for most values of OCR. These approximations also allow the rapid identification of situations where hyperbolic consumption forms can result in significant differences from constant consumption rate models, and so can reduce the computational workload associated with numerical solutions, by estimating both the oxygen diffusion distances and resultant oxygen profile. Such analysis may be useful for parameter fitting in large imaging datasets and histological sections, and allows easy quantification of projected differences between functional forms of OCR.
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影响因子：
3.8
作者：
Secomb, TW;Hsu, R;Dewhirst, MW
通讯作者：
Dewhirst, MW
DOI：
10.1016/0360-3016(88)90313-6
发表时间：
1988-09-01
影响因子：
7
作者：
GROEBE, K;VAUPEL, P
通讯作者：
VAUPEL, P
影响因子：
3.5
作者：
Das, Shiva K.;Ten Haken, Randall K.
通讯作者：
Ten Haken, Randall K.
DOI：
10.1016/0360-3016(93)90070-c
发表时间：
1993-02-15
影响因子：
7
作者：
SECOMB, TW;HSU, R;GROSS, JF
通讯作者：
GROSS, JF
影响因子：
1.9
作者：
Sherratt, JA;Chaplain, MAJ
通讯作者：
Chaplain, MAJ