Irradiated points and light receiving points are arranged such that sampling
points are arranged over an entire spherical head with no vacant space. The sampling
points are arranged to cover the entire spherical head by combining a plurality
of rhombic shells and inverting the respective positions of irradiated points and
light receiving points in the adjacent shells. As a result, a whole brain probe
capable of covering the entire head is provided to allow an image of the whole
brain to be viewed as a single image.
