The CTDOR geometry: an optimized data treatment to demonstrate its potential

In order to decrease the patient's radiation exposure from Computed Tomography, the new CT geometry CTDOR has been invented. It consists of two data sets: A conventional arc or flat panel detector and a mask ring with shieldings on the outside and detectors on the inside separated by windows. Combined with the reconstruction algorithm OPED, it has the theoretical potential to decrease the dose about 50% while providing the same image quality as conventional systems. First steps to evaluate this theory were done with a mask ring demonstrator combined with a conventional C-arm device. Although the quality of the demonstrator is limited, this set-up was supposed to demonstrate how the combination of the two data sets works in principle. Preliminary results from earlier studies, however, provided images of rather poor quality. This work presents better images obtained with an optimized data treatment. We showed that most artifacts are eliminated and that we get sharper images with higher contrast compared to the images reconstructed from the single data sets and compared to the earlier study. Regarding the limitations of the set-up, the resulting images were remarkably good. CTDOR is therefore a promising method, which is worth to perform further studies.