Macromolecules and drug delivery to solid tumours is strongly influenced by fluid flow through interstitium, and pressure-induced tissue deformations can have a role in this. Recently, it has been shown that temperature-induced tissue deformation can influence interstitial fluid velocity and pressure fields, too. In this paper, the effect of modulating-heat strategies to influence interstitial fluid transport in tissues is analysed. The whole tumour tissue is modelled as a deformable porous material, where the solid phase is made up of the extracellular matrix and cells, while the fluid phase is the interstitial fluid that moves through the solid matrix driven by the fluid pressure gradient and vascular capillaries that are modelled as a uniformly interspersed fluid point-source. Pulsating-heat generation is modelled with a time-variable cosine function starting from a direct current approach to solve the voltage equation, for different pulsations. From the steady-state solution, a step-variation of vascular pressure included in the model equation as a mass source term via the Starling equation is simulated. Dimensionless 1D radial equations are numerically solved with a finite-element scheme. Results are presented in terms of temperature, volumetric strain, pressure and velocity profiles under different conditions. It is shown that a modulating-heat procedure influences velocity fields, that might have a consequence in terms of mass transport for macromolecules or drug delivery.

中文翻译：

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脉动热源对肿瘤组织间质液转运的影响

大分子和药物向实体瘤的输送受到通过间质的流体流动的强烈影响，压力引起的组织变形可能在其中起作用。最近，已经表明温度引起的组织变形也会影响间质流体速度和压力场。本文分析了调热策略对组织间质液转运的影响。整个肿瘤组织被建模为一种可变形的多孔材料，其中固相由细胞外基质和细胞组成，而液相是在流体压力梯度和毛细血管的驱动下穿过固体基质的间质液。被建模为均匀散布的流体点源。脉动热产生是用时变余弦函数建模的，从直流方法开始，以求解不同脉动的电压方程。从稳态解中，通过 Starling 方程模拟包含在模型方程中作为质量源项的血管压力的阶跃变化。无量纲一维径向方程使用有限元方案进行数值求解。结果以不同条件下的温度、体积应变、压力和速度曲线表示。结果表明，调节热过程会影响速度场，这可能会对大分子的质量传输或药物输送产生影响。通过Starling方程模拟包含在模型方程中作为质量源项的血管压力的阶跃变化。无量纲一维径向方程使用有限元方案进行数值求解。结果以不同条件下的温度、体积应变、压力和速度曲线表示。结果表明，调节热过程会影响速度场，这可能会对大分子的质量传输或药物输送产生影响。通过Starling方程模拟包含在模型方程中作为质量源项的血管压力的阶跃变化。无量纲一维径向方程使用有限元方案进行数值求解。结果以不同条件下的温度、体积应变、压力和速度曲线表示。结果表明，调节热过程会影响速度场，这可能会对大分子的质量传输或药物输送产生影响。