3D Fuse Deposition Manufacturing Of Tissue-simulating Phantom For Biomedical Optical Imaging

The biomedical optical imaging instruments(such as OCT, photoacoustic imaging, two-photon fluorescence imaging, two harmonic imaging, optical tomography etc.) can detect the structural features, the optical properties and the functional characteristics of the biological tissues in real time. Also, it has been widely applied in clinical analysis and pathological research. However, its high detection precision depends on the proper calibration. And the existing calibration models(tissue optical phantoms)are mainly made from homogeneous materials without considering the heterogeneous structural features and the optical properties of the biological tissues, which may lead to the measurement errors. Hence it has important practical significances for us to develop a tissue optical phantom which has high simulation precisions in both structure features and optical properties.In order to fabricate such a phantom, we have developed a mixed materials FDM (fuse deposition)3D printing system, which uses the gel-wax, graph power and TiO2power as the base material, absorber material and scatter material. And the the printing materials’s optical properties are measured by the instruments like commercial oximetry, spectrophotometer and double integrating sphere. When the system works,all the printed materials are mixed in the dynamic mixing nozzle according to the biological tissue’s optical properties corresponding material proportions and then squeezed out. Through the coordinated movements of the3d mobile platform and the nozzle, these squeezed out materials are piled up layer by layer on the molding platform in accordance with the structural features of the biological tissues.To verify that the above3D printing system can fabricate the tissue optical phantoms which can simulate the structural features of the biological tissues, we have collected the serial MRI(magnetic resonance imaging) images of human brain images in this experiment. And then we get the reverse reconstruct3D digital model in the3D-slicer software and print out the heterogeneous model of forehead brain. In the end, we compare the results of MRI images/images/print simplified MRI slice images.To verify that the above3D printing system can fabricate the tissue optical phantoms which can simulate the structural features of the biological tissues, we have compared the light intensity distribution situation of the real test results of the two layers optical phantoms fabricated by piled up layers with the MCML (multilayer structure analysis of Monte Carlo simulation) simulation test results according to the real test parameters.The above experiments and simulation results have demonstrated that the mixed materials FDM (fuse deposition)3D printing system can fabricate the heterogeneity tissue optical phantoms which can simulate the structural features and the optical properties of the biological tissues. Furthermore, our research work provides a feasible reference method for promoting the standardization of biomedical photonics imaging instruments calibration.