Fast method for the estimation of the absorbed dose in X-ray microtomography

Abstract

Micro-CT imaging is an increasingly popular tool in the internal investigation of objects and materials. However, as an X-ray based technique, a potentially harmful radiation dose is deposited in the sample during the measurement. In (non small-animal) micro-CT imaging one is dealing with a strong variation in measurement systems and settings, resulting in many different acquisition circumstances and the absence of standard imaging protocols. Therefore, the deposited dose is rarely studied for micro-CT applications. This research aimed at developing a fast simulation technique to predict the dose associated with micro-CT scanning. Its performance is compared with that of two different Monte Carlo simulation tools and with a straight forward approach to estimate an upper limit for the dose. The fast simulation method, obtaining a dose estimation based on the energy absorption coefficient, is much faster than the Monte Carlo simulations, and the results are accurate within 30%. This enables us to predict the dose for a known sample and a known scanner setup, without complex Monte Carlo simulations and will allow researchers to avoid radiation damage or unwanted radiation induced effects, an increasingly important concern in 3D and 4D micro-CT scanning.