https://en.formulasearchengine.com/w/api.php?action=feedcontributions&feedformat=atom&user=49.248.160.149formulasearchengine - User contributions [en]2026-09-29T08:23:24ZUser contributionsMediaWiki 1.47.0-wmf.7https://en.formulasearchengine.com/w/index.php?title=Superexchange&diff=22035Superexchange2013-11-20T12:47:33Z<p>49.248.160.149: </p>
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<div>'''Photon diffusion equation''' is a second order [[partial differential equation]] describing the time behavior of photon fluence rate distribution in a low-absorption high-scattering medium.<br />
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Its mathematical form is as follows.<br />
<math>\nabla(D(r)\cdot\nabla)\Phi(\vec{r},t)-v\mu_a(\vec{r})\Phi(\vec{r},t)+vS(\vec{r},t)=\frac{\partial\Phi(\vec{r},t)}{\partial t}</math><br />
where <math>\Phi</math> is photon [[fluence rate]] (W/cm<sup>2</sup>), <math>\mu_a</math> is absorption coefficient (cm<sup>−1</sup>), <math>D</math> is [[diffusion constant]], <math>v</math> is the speed of light in the medium (m/s), and <math>S</math> is an isotropic source term (W/cm<sup>3</sup>).<br />
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Its main difference with [[diffusion equation]] in physics is that photon diffusion equation has an absorption term in it.<br />
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==Application==<br />
===Medical Imaging===<br />
[[diffuse optical tomography]]<br />
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==External links==<br />
* [http://www.lrsm.upenn.edu/pmi Diffuse Optics Lab at University of Pennsylvania, Philadelphia, USA]<br />
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[[Category:Equations]]</div>49.248.160.149