Table 1.

Glossary of terms

High-pressure freezingMethod for freezing large volumes of tissue that depends on application of high pressures to prevent formation of ice crystals.
Freeze-substitutionIce in frozen tissue is replaced with an organic solvent, thereby introducing stabilizing molecules and heavy metal stains into the tissue.
Fiducial markerGold particles applied to sections to aid fine alignment of a set of tilted images.
Projection angleComplement of the angle between the specimen plane and the incoming electron beam.
BackprojectionReverse of projection to yield a 3D reconstruction, or tomogram, from a set of tilted images.
Missing pyramidBlind spot in two axis tomographic series attributable to limitations in tilt angle, leading to a loss of resolution in the final tomogram.
TomogramComputed 3D volume based on backprojections of all images from a tilt series.
Virtual sectionAny individual section computed from a tomogram whose minimum thickness is one 3D pixel, or voxel.