Narrow-beam X-ray Luminescence Tomography Imaging System And Reconstruction Method Research

Narrow-beam X-ray luminescence tomography imaging(XLT) is a novel molecular imaging technology. Its basic principle is to use a series of narrow beam X-rays to excite the phosphor nanoparticles(PNPs) in biological tissues. PNPs can emit luminescence signal after excitation, which will be received by certain detectors and applied in reconstruction to recover the distribution of PNPs in tissues. Its main advantages are as follows: first, compared with conventional optical molecular imaging, we can get rid of the significant autofluorescence signal in this imaging modality; second, XLT can realize imaging at a deeper depth in tissue due to the deep penetration effect of X-rays; third, the resolution of XLT is closely related to the width of the narrow beam X-rays.Based on the current narrow-beam XLT systems researches, we self-developed the hybrid imaging system combining X-ray computed tomography system and narrow-beam X-ray luminescence imaging system. A series of simulations and phantom experiments were done under the conditions of this system. We first did narrow-beam XLT self-developed system tests, which included measuring the width of narrow beam, the intensity of light signals at different wavelengths and several simple phantom penetration tests.Based on the above basic tests of the system, we studied narrow-beam XLT three-dimensional reconstruction. Since the recovery of the three-dimensional distribution of PNPs in tissues is an ill-posed problem, we applied the split bregman method to narrow-beam XLT reconstruction to overcome the ill-posedness. We used the spit bregman and algebra reconstruction technique(ART) to XLT reconstruction, and the reconstruction results of simulation experiments showed that split bregman method had a smaller distance error and displayed a better contour of the PNPs. We also drew the conclusion that the reconstruction distance error increased with the depth of PNPs and the width of narrow-beam X-ray. Finally, phantom experiment used the dual imaging system was designed to verify the feasibility of split bregman reconstruction method. Experimental results showed that split bregman method obtained smaller reconstruction error distance and displayed a better PNPs contour in the phantom. Sowe further verify the feasibility and effectiveness of the system and method.