Xray imaging is a well established technique of detecting strongly attenuating materials and has been applied to a number of inspection applications within the agricultural and food industries. However, there are still areas within these industries in which the technique has been underexploited. In particular there are many applications within the biological sciences where we wish to detect weakly attenuating materials against a similar background material. It is in this area that Xray inspection techniques need to be developed. This paper seeks to show how transmission imaging could be better exploited. In particular it is shown that the image contrast between softly attenuating materials can be enhanced by optimally selecting the Xray energy and improving the spatial resolution. The paper also presents full three dimensional reconstructions of samples obtained using computer tomography (CT) techniques and discusses the potential of these methods.