A co-planar, simultaneous, photoacoustic tomography guided, diffused optical tomography (CS-PAT-DOT) methodology has been presented in this paper. We detect the absorption of sub-regions with different absorption characteristics in deep tissue with a high spatial resolution. To this aim, we initially utilize compressed sensing (CS), time reversal (TR) and back projection (BP) reconstruction algorithms to reconstruct a priori information inside a heterogeneous phantom. Then the reconstructed images are used in DOT image reconstruction through the total variation method. Improvements obtained from such hybrid methodology are measured by comparing DOT and CS-PAT-DOT images. It will also show that each of the reconstructions based on the proposed method has a unique capability to accurately detect heterogeneities in the tissue at different depths; significantly improving spatial resolution in DOT images. The focus of this study is directed towards quantifying the concentrations of endogenous chromophores, e.g., oxyhemoglobin, deoxyhemoglobin and cytochrome-c-oxidase etc., which are significant indices in detecting tissue abnormalities.
These days, the biological effects of electromagnetic (EM) radiations on the brain, especially in the frequency range of mobile communications, have caught the attention of many scientists. Therefore, in this paper, the propagation of mobile phone electromagnetic waves in the brain tissues is investigated analytically and numerically. The brain is modeled by three layers consisting of skull, grey and white matter. First, we have analytically calculated the microwave reflection, transmission, and absorption coefficients using signal flow graph technique. The effect of microwave frequency and variations in the thickness of layers on the propagation of microwave through brain are studied. Then, the penetration of microwave in the layers is numerically investigated by Monte Carlo method. It is shown that the analytical results are in good agreement with those obtained by Monte Carlo method. Our results indicate the absorbed microwave energy depends on microwave frequency and thickness of brain layers, and the absorption coefficient is optimized at a number of frequencies. These findings can be used for comparing the microwave absorbed energy in a child's and adult's brain.
The accurate quantification of lesions located in deep tissue is an important challenge in diffuse optical tomography (DOT), while photoacoustic tomography (PAT) as a non-invasive optical imaging provides high-resolution imaging of optical contrast in deep tissue that can be served as a complementary modality to improve the accuracy of DOT. Here, we coupled advantages of photoacoustic tomography (PAT) to diffuse optical tomography (DOT) for enhancing reconstructed DOT images. Using a priori information provided by PAT was used to reasonably regularize the DOT inversion procedure.. The results show that hybrid DOT-PAT can provide high-resolution image in deep tissue.