Assessing the tissue-imaging performance of confocal microscope architectures via Monte Carlo simulations

Various confocal microscope architectures have been developed for in vivo tissue imaging, including single-axis confocal (SAC) and dual-axis confocal (DAC) configurations utilizing both point-scanning (PS) and line-scanning (LS) approaches. While it is known that these design variations lead to tradeoffs in imaging performance, a quantitative comparison of the imaging performance of these configurations in highly turbid media would be of value. Here, we perform Monte Carlo simulations to evaluate the optical-sectioning capability of these various confocal microscope architectures in reflectance mode. In particular, we investigate the axial and transverse responses of these configurations to reflective targets at various depths within a homogenous scattering medium. We find that the DAC-PS configuration results in superior rejection of multiply scattered background light compared to all other configurations, followed in performance by the SAC-PS, the DAC-LS, and then the SAC-LS. Line scanning with both the DAC and SAC configurations leads to photon crosstalk between pixels. However, at shallow depths, the axial and transverse resolution of all configurations is maintained in a homogeneous scattering medium.