Source: Peiman Shahbeigi-Roodposhti and Sina Shahbazmohamadi, Biomedical Engineering Department, University of Connecticut, Storrs, Connecticut

It's a little-known fact that the discovery and (inadvertent) use of X-rays garnered the first ever Nobel Prize in Physics. The famous X-ray image of Dr. Röntgen's wife's hand from 1895 that sent shock waves through the scientific community looks like most modern day 2D medical X-ray images. Though it is not the newest technology, X-ray absorption imaging is an indispensable tool and can be found in the world's top R&D and university labs, hospitals, airports, among other places. Arguably the most advanced uses of X-ray absorption imaging involve attaining information like the kind found in a 2D medical X-ray but realized in 3D through a computed tomography (CT or micro-CT). By taking a series of 2D X-ray projections, advanced software is capable of reconstructing data to form a 3D volume. The 3D information can, and most likely will include information from the inside of the probed object without having to be cut open. Here, a micro-CT scan will be obtained, and the major factors impacting image quality will be discussed.

1. Mounting a Sample (Bone)

1. For examining a network of bones, like a spine, suspend the structure in an agarose gel and allow to cure in a very thin-walled plastic tube (Figure 2). The thinness of the tube is very important, greatly affecting the signal throughput and overall image quality. This in turn affects your ability to resolve features. The transmission value of the tube should be as close to 100% as possible.
2. Mount the tube on sample stage with tape or by making a custom stand, ultimately e

The following images give an overview of results that can be obtained from using micro-CT with the above stated procedure. Qualitative measurements on varying absorption can be directly noted based on these images. Quantitative data such as material porosity, feature size and distribution, etc. would require additional image processing in a different software.

Figure 3: 3D volume of mouse spinal cord (

This experiment examined the many factors that should be considered when using micro-CT, particularly for a biological sample. This project was designed to help the investigator understand how their decisions will impact the data that micro-CT can provide. As demonstrated there are many dependent and sensitive parameters that should be considered including: mounting, X-ray energy, exposure time, source and detector positioning, number of projections, and total scan angular displacement. This exercise is meant as an intro