Electron Tomography
Electron tomography images the interior of cells in a near-native state by recording 2D projections over a range of tilt angles and reconstructing a 3D volume. This base follows the imaging chain: from vitrified sample preparation and tilt-series acquisition, through the missing wedge — its central limitation — to alignment and 3D reconstruction.
Reconstructed from 40 projections over a ±90° range. More projections → sharper, fewer star-streaks; when tilt is capped at ±90° (< 90°) the un-sampled angles stretch and blur the recon along one direction — the missing wedge, seen in real space.
Articles in this base 9 articles
What cryo-EM is
Freeze molecules in vitreous ice and image them with electrons — what cryo-EM is, and its two main roads.
Imaging and data acquisition
From sample prep and flash-freezing, through the electron optics and detector, to how a micrograph (or a whole tilt series) is actually collected.
Fundamental limits
The dose–resolution trade-off, sample thickness, and the missing wedge unique to tomography — the hurdles cryo-EM cannot get around.
Cryo-EM & vitrification
Rapid freezing turns a biological specimen into vitreous ice, preserving native structure for electron imaging.
Tilt-series acquisition
A tomogram is built from many 2D projections recorded as the specimen is tilted through a range of angles.
The Missing Wedge
Why are Cryo-ET reconstructions always stretched along the vertical axis?
Tilt-series alignment & fiducials
Before reconstruction, projections must be registered to a common geometry that corrects stage shift and specimen drift.
From tilt series to tomogram
How does a stack of 2D projections become a 3D volume? Backprojection, why you need many angles, and where the missing wedge comes from
In situ structural biology
Cryo-ET resolves macromolecular structures directly inside cells, in their native cellular context.