Optical tomography, the ability to inspect biological organisms without affecting their functional and vital structures, is an evolving research area that encourages advancement in the study of biological processes.
However, modern measurement methodologies sometimes fail to meet the demands of biomedical imaging. In particular, the process of light diffusion through opaque tissues and problems due to alignments of the experimental setup enormously limit the quality of the results obtainable with conventional microscopy techniques.
In this context, the idea behind the "High-resolution Imaging with Phase Retrieved Tomography" project (HI-PHRET) is to reach the maximum tomographic resolution assisted by an effective imaging pipeline. To do this, we put cutting-edge photonics and computational phase retrieval techniques at the service of the biomedical imaging world.
Mechanical misalignments, light scattering problems, and imaging of objects hidden behind opaque structures were tackled with new implementations of multi-dimensional phase retrieval methods. The project has been structured in three phases, interfacing theory, experiments, and using tailored computational methods:
- We developed a new multi-dimensional and multispectral phase retrieval techniques for the inversion of autocorrelation, by exploiting the computational power offered by GPUs.
- We exploited these methods for the tomographic reconstruction of the fluorescent distribution from biological samples in an optical microscopy setup. Our technique is free from any alignment issues, permits the reconstruction accurate at the sub-pixel level, and achieved a resolution higher than the state-of-art methods.
- Further, we extended the method to perform hidden tomography without the use of lenses, reconstructing samples not directly visible due to the presence of an optically opaque barrier.
