Fast dual-energy micro-CT with reliable detection of iodine in thin vessels

X-ray micro-computed tomography (μCT) is a widely used imaging modality in preclinical research, with a range of specific applications. Minimising the dose both from x-rays and of administered contrast agents such as iodine is desirable for the improvement of research and subject outcomes. Here, we introduce a new data processing scheme that enables accurate localisation and quantification of iodine concentrations resulting from fast, low dose μCT scans. The technique makes use of characteristic shape detection to selectively decompose dual-energy x-ray μCT data in iodine-containing regions only, thus removing any background iodine signal in the decomposed basis. We demonstrate the technique's effectiveness using scan data acquired over 3.6 s and a dose to water of 8.7 mGy where the weakest concentration of iodine successfully isolated was 21 mgI ml^-1in a 500 μm diameter vessel, and note that this scan speed could be further improved with a detector with a faster framerate. The technique is extended to complex vessel shapes in three dimensions and remains robust. It is expected to be useful in the context of small animal imaging as the low dose requirements increase the repeatability of scans per subject.