Flyckt V M M, Raaymakers B W, Lagendijk J J W
Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
Phys Med Biol. 2006 Oct 7;51(19):5007-21. doi: 10.1088/0031-9155/51/19/018. Epub 2006 Sep 19.
Prediction of the temperature distribution in the eye depends on how the impact of the blood flow is taken into account. Three methods will be compared: a simplified eye anatomy that applies a single heat transfer coefficient to describe all heat transport mechanisms between the sclera and the body core, a detailed eye anatomy in which the blood flow is accounted for either by the bioheat approach, or by including the discrete vasculature in the eye and the orbit. The comparison is done both for rabbit and human anatomies, normo-thermally and when exposed to homogeneous power densities. The first simplified model predicts much higher temperatures than the latter two. It was shown that the eye is very hard to heat when taking physiological perfusion correctly into account. It was concluded that the heat transfer coefficient describing the heat transport from the sclera to the body core reported in the literature for the first simplified model is too low. The bioheat approach is appropriate for a first-order approximation of the temperature distribution in the eye when exposed to a homogeneous power density, but the discrete vasculature down to 0.2 mm in diameter needs to be taken into account when the heterogeneity of the temperature distribution at a mm scale is of interest.
眼睛温度分布的预测取决于如何考虑血流的影响。将比较三种方法：一种简化的眼睛解剖模型，它应用单一的传热系数来描述巩膜与身体核心之间的所有热传递机制；一种详细的眼睛解剖模型，其中血流要么通过生物热方法来考虑，要么通过纳入眼睛和眼眶中的离散血管系统来考虑。对兔子和人体解剖模型在正常体温以及暴露于均匀功率密度下的情况都进行了比较。第一个简化模型预测的温度比后两个模型高得多。结果表明，当正确考虑生理灌注时，眼睛很难被加热。得出的结论是，文献中报道的第一个简化模型中描述从巩膜到身体核心热传递的传热系数过低。当暴露于均匀功率密度时，生物热方法适用于对眼睛温度分布进行一阶近似，但当关注毫米尺度上温度分布的不均匀性时，需要考虑直径小至0.2毫米的离散血管系统。
