Tomography

About a month ago I posted an entry about the microscopes in my lab. In this previous post, I briefly described a technique called Electron Tomography. Here is great video that describes in detail the process of making a tomogram. The section used for this was 500 nanometers thick. This is extremely thick for an electron microscope. The data taken for this tomogram was gathered on one of the world's three 1 Million kV transmission electron microscopes! Most microscopes only have the capability to gather images on sections no thicker than 200 nanometers.
About a year ago I was in a class at the New York Structural Biology Center about electron microscopy techniques. The lesson about electron tomography was taught by the person who made this particular tomogram.

Microscopes in the lab

Here are a couple of pictures I took of the two Transmission Electron Microscopes (click to enlarge) that are currently in our lab. I Photoshoped them a little to cut out the background. On the left is the Philips CM-12. This is our work-horse and the instrument that I use the most. It's source is a Tungsten Filament that can run at 120kV. Most of the TEM images that you will see on this blog were taken using this microscope.
On the right is the Philips CM-200. This microscope is mostly used by the structural biologists in the institute for studying protein crystals and single particles. It's source is a Field Emission Gun that can run at 200kV. The CM-200 has a special cryo-stage for doing cryo-electron microscopy can also be controlled by a computer. This is handy for doing Electron Tomography, a special type of imaging that can make 3D reconstructions. See movie below.

By the way, I can't take credit for this video. Whoever created it likely spent years developing getting the right conditions for the sample and many many hours on image acquisition and processing.