Figure 6.

Simulated photon propagation through the head. (A) Typical anatomical MRI scan, with NIN sensor fiducial markers visible above the scalp. (B) Segmentation of the MRI scan in (A) into separate tissue types where Python was used to chain together the MRI segmentation modules. (C) Example photon densities for a single source–detector pair separated by 4 cm, overlaid on the segmented head. The colored areas delimit the region to which many NIN instruments would be sensitive, with a loss of 1 order of magnitude sensitivity per contour line. Images were generated using matplotlib.imshow(), NumPy masked arrays, and matplotlib.contour().