Small volume of mouse cortex is already successfully scanned at 3x3x20nm voxel resolution, with smallest synaptic details being visible <a href="http:&#x2F;&#x2F;www.cell.com&#x2F;abstract&#x2F;S0092-8674(15)00824-7" rel="nofollow">http:&#x2F;&#x2F;www.cell.com&#x2F;abstract&#x2F;S0092-8674(15)00824-7</a>
The tool is called ATLUM. The process could be scaled up.