Abstract
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Objectives For specific modeling of light propagation in complicated tissues, a hybrid SP3-diffusion-radiosity equation based light transport model was proposed for the reconstruction of Cerenkov luminescence tomography, which aimed to cater for the tissues' structural heterogeneity and optical specificity and provide a perfect comprise between the accuracy and effectiveness.
Methods The emission of Cerenkov luminescent light covers a large range of spectrum from 400 to 900 nm. In such a board spectrum, the complicated biological tissues has not only structural heterogeneity but also exhibits optical specificity. To solve this problem, a hybrid SP3-diffusion-radiosity equation was proposed for the reconstruction of Cerenkov luminescence tomography. In the model, the third-order simplified spherical harmonics approximation (SP3) was used to describe light transport in the low scattering regions, the diffusion approximation (DA) was adopted for light transport in the high scattering regions, and the radiosity theory equation was utilized for the non-scattering regions. A set of boundary conditions were established to construct an identical equation for the hybrid light transport model.
Results To verify the accuracy and performance of the proposed hybrid light transport model, a self-designed heterogeneous geometry was employed, as shown in Fig. 1(a) and (b). To simulate the internal radionuclide source, a single sphere of 1mm radius and 0.238nW/mm3 power density was placed at (0, 1, 0)mm. All of the calculation results of the proposed model were compared with the simulation ones from the Monte Carlo method. Three curves were extracted from the profile surface at height of 0, 4, 8mm respectively, and the comparison curves were plotted in Fig. 1(c)-(e).
Conclusions The primary result illustrated that the proposed model well solved the problem of Cerenkov light transport in tissues with both the structural heterogeneity and optical specificity.
Research Support This work was partly supported by the Program of the National Basic Research and Development Program of China (973) under Grant No. 2011CB707702, the National Natural Science Foundation of China under Grant Nos. 81090272, 81227901, 81101083, 81201137, the Open Research Project under Grant 20120101 from SKLMCCS, and the Fundamental Research Funds for the Central Universities.