Electron Tomography


Tomography – imaging by sections

Greek – tomos means section/slice/cutting

Radiation source

X-rays gamma rays

Type of tomograph

CT (computed tomography)

SPECT (single photon emission tomography) electron-positron annihilation PET (positron emission tomog.) nuclear magnetic resonance ultrasound electrons ions

MRI (magnetic resonance imaging) ultrasonography

3D TEM atom probe

Three dimensional imaging in TEM



Alignment of adjacent sections is one of the most difficult aspects of serial reconstruction

Registration points are often used to assist alignment (registration)

Electron Tomography

Electron Tomography

An object viewed from many different angles will generate slightly different images.

Object creates multiple images so the inverse is also possible

These images can be recorded and analyzed to create a tomographic rendering of the specimen.

It is computationally easier to carry out the calculations in Fourier space than it is in image space.

Single reverse FFT

-can enhance symmetry

M.ultiple images can be generated in one of two ways:

1) A single object can tilted and viewed from many different angles.

2) A field of randomly oriented identical objects can be image in a tilt pair.

Electron Tomography

Double tilt holder

Gatan cryo-holder allows samples to be placed into the TEM while being kept frozen at LN temperatures

Solid models constructed from various views