Theoretical Comparison of the Iodine Quantification Accuracy of Two Spectral CT Technologies
2014 (English)In: IEEE Transactions on Medical Imaging, ISSN 0278-0062, E-ISSN 1558-254X, Vol. 33, no 2, 556-565 p.Article in journal (Refereed) Published
We compare the theoretical limits of iodine quantification for the photon counting multibin and dual energy technologies. Dual energy systems by necessity have to make prior assumptions in order to quantify iodine. We explicitly allow the multibin system to make the same assumptions and also allow them to be wrong. We isolate the effect of technology from imperfections and implementation issues by assuming both technologies to be ideal, i.e., without scattered radiation, unity detection efficiency and perfect energy response functions, and by applying the Cramer-Rao lower bound methodology to assess the quantification accuracy. When priors are wrong the maximum likelihood estimates will be biased and the mean square error of the quantification error is a more appropriate figure of merit. The evaluation assumes identical X-ray spectra for both methodologies and for that reason a sensitivity analysis is performed with regard to the assumed X-ray spectrum. We show that when iodine is quantified over regions of interest larger than 6 cm, multibin systems benefit by independent estimation of three basis functions. For smaller regions of interest multibin systems can increase quantification accuracy by making the same prior assumptions as dual energy systems.
Place, publisher, year, edition, pages
2014. Vol. 33, no 2, 556-565 p.
Dual energy computed tomography (CT), iodine quantification, photon counting multibin CT, spectral CT
Radiology, Nuclear Medicine and Medical Imaging
IdentifiersURN: urn:nbn:se:kth:diva-143448DOI: 10.1109/TMI.2013.2290198ISI: 000331298000027ScopusID: 2-s2.0-84894053605OAI: oai:DiVA.org:kth-143448DiVA: diva2:707475
QC 201403242014-03-242014-03-212014-03-24Bibliographically approved