Time Resolved Optical Tomographic imaging: A simulation study

Time Resolved Optical Tomographic (TROT) modality is a promising, non invasive, free of extra dosimetric load, yet challenging, diagnostic method in modern Medical Imaging. It could be potentially employed to provide the necessary anatomical information of an area under examination so much as an autonomous, but also as a supportive system to existing techniques such as the Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET). The current work focuses on the feasibility of a TROT system by means of a Monte-Carlo study, utilizing light transport software packages for modeling appropriate optical phantoms and the analysis of the obtained spatial-time signals. Due to the highly diffusive nature of the near infrared radiation through tissue environment, commonly related to this type of imaging, proper resolving limits in the form of time-cuts must be applied on the detected rays in order to separate the diffused from the non-scattered photons. The non-scattered time resolved photons, due to the non-divergent nature of their propagation, can provide the accurate planar information which was further analyzed to reconstruct the tomographic images and from them the final 3D image of the optical phantom. Obtained transport simulation results are presented in the current study and the quality of the tomographically reconstructed images with respect to the spatial-time efficiency of the system is further discussed.