Fisher information for the design of diffuse optical brain monitoring systems

Diffuse optical tomography is a non-invasive technique for assessing tissue structure and function by detecting scattered near-infrared light. A key question is how to select source–detector configurations and measurement modalities to maximise sensitivity, particularly for brain defects (e.g. tumour, stroke, etc.) monitoring. This study proposes Fisher information as a rapid, quantitative metric to optimise source-detector placement. We compare the performance of continuous-wave and time-resolved measurements and also explore the impact of cerebrospinal fluid on system design. This method confirms some known results but also highlights some counter-intuitive results, including the finding that optimal source-detector distance depends on the type of detector and its related noise statistics and that the low-scattering cerebral spinal fluid layer in the brain can enhance measurement sensitivity. This is found to depend on how exactly the data is collected and processed, with fully time-resolved data always showing a net gain. Our results provide an efficient framework for analysing and designing diffuse optical imaging systems for non-invasive monitoring and imaging via diffuse light