Crosshair is a systematic approach to semi-automate an ultramicrotome operation for targeting a specific plane aided by X-ray tomography measurements, particularly when targeting a ROI in a large sample. Automation was introduced to two recent commercial systems in the form of motorisation for each of the ultramicrotome axes, allowing precise and automated angular movement for both systems, as well as translational movement for one system. The software allows selection of a plane of interest from X-ray images, and preforms an automatic conversion into angles and cutting depths for the ultramicrotome. The result is a faster and more accurate orientation of the image acquisition planes for volume electron microscopy, a task that has traditionally been difficult and time-consuming. Crosshair is provided as an open-source, user-friendly Fiji (Schindelin et al., 2012) plugin.

Taken from Meechan K., et al., Crosshair, semi-automated targeting for electron microscopy with a motorised ultramicrotome. Elife. 2022 Nov 15;11:e80899.