CT is about producing a 3-dimensional visualisation of an object. To achieve that the camera of a CT scanner needs to make a full circle around the object, sometimes taking thousands of x-ray images.
“The alternative we are researching is a so called plenoptic camera with an optical system that lets us record a 3D image from a single position," explains Marta Fajardo, researcher in plasma physics and VOXEL project coordinator. "This type of camera has been shown to work in visible light. What we're trying to do is to make it work in the x-ray spectrum.”
But how to get a 3D image from a single shot? The researchers take x-rays by adjusting the beam in a maze of lenses and mirrors until it passes through the studied object. This matrix of micro-lenses is the key optical element. It allows changing the focus after the photo has been taken – thanks to newly developed algorithms for image reconstruction.
Engineer Ombeline De La Rochefoucauld goes into more detail: "By combining the main lens with this matrix, we will collect rays with all the relevant spatial and directional information. So the raw image will provide us with all necessary data to produce a 3-dimensional reconstruction."
X-rays are trickier to work with than visible light, so it will take years of research to produce x-ray 3D images of relatively large objects. But in microscopy, this approach already offers a compact and affordable alternative to large research facilities like synchrotrons.
The VOXEL project (Volumetric medical X-ray imaging at extremely low dose) runs for 4 years until May 2019. Its total budget of close to 4 Million Euros is met by the EU.
A report on the project is featured on Futuris, the science programme of the pan-European television channel Euronews. It can be watched anytime online (see links below) and on TV until 22 October 2017 at the following times:
- Monday 18:45
- Tuesday 01:45, 13:15, 18:15
- Wednesday 10:15, 16:45
- Thursday 14:15, 17:15
- Friday 11:45, 15:45
- Saturday 06:45, 12:15, 22:15
- Sunday 10:45, 20:45
All times Central European Summer Time.
If you are in Ireland, Portugal or the United Kingdom: Tune in 1 hour earlier.
If you are in Bulgaria, Cyprus, Estonia, Finland, Greece, Latvia, Lithuania or Romania: Tune in 1 hour later.