Peter B. Noel PhD, Presenter: Nothing to Disclose

Bernhard Clemens Renger MSc, Abstract Co-Author: Nothing to Disclose

Martin Fiebich, Abstract Co-Author: Nothing to Disclose

Alexander Andre Fingerle MD, Abstract Co-Author: Nothing to Disclose

Daniela Muenzel MD, Abstract Co-Author: Nothing to Disclose

Martin Dobritz MD, Abstract Co-Author: Nothing to Disclose

Ernst J. Rummeny MD, Abstract Co-Author: Nothing to Disclose

Evaluation of 15000 computed tomography (CT) examination to investigate if iterative reconstruction (IR) reduces sustainably radiation exposure.

Information from 15000 CT examination were collected, including all aspects of the exams such as scan parameter, patient information, and reconstruction instructions. The examinations are acquired between January 2010 and December 2012, while after 15 month a first generation IR algorithm was installed on a 256-slice MDCT. To collect the necessary information from PACS, RIS, MPPS and structured reports a Dose Monitoring System (DMS) was developed. To harvest all possible information an optical character recognition system was integrated, for example to collect information from the screenshot CT-dose-report. The tool transfers all data to a database for further processing such as the calculation of effective dose and organ doses. To evaluate if IR provides a sustainable dose reduction the effective dose values were statistically analyzed with respect to protocol type, diagnostic indication, and patient population.

IR has an impact to reduce radiation dose significantly. Before clinical introduction of IR the average effective dose was 10.1±7.8mSv and with IR 8.9±7.1mSv. Especially in CTA, with the possibility to use kV reduction protocols, such as in aortic CTAs (before IR: average14.2±7.8mSv; median11.4mSv /with IR: average9.9±7.4mSv; median7.4mSv), or pulmonary CTAs (before IR: average9.7±6.2mSV; median7.7mSv /with IR: average6.4±4.7mSv; median4.8mSv) the dose reduction effect is major. On the contrary for unenhanced low dose scans of the cranial (for example sinuses) the reduction is minor (before IR: average6.6±5.8mSv; median3.9mSv /with IR: average6.0±3.1mSV; median3.2mSv).

Iterative reconstruction algorithms reduce sustainably and significantly radiation dose in the clinical routine. The amount of radiation dose reduction cannot be generalized to a fixed amount since the initial dose depends on the diagnostic indication and protocol design.

The dose aspect remains a priority in CT research. Our results illustrate that not only in studies with a limited number of patients but in the clinical routine IRs provide long-term dose saving.

Noel, P, Renger, B, Fiebich, M, Fingerle, A, Muenzel, D, Dobritz, M, Rummeny, E, Does Iterative Reconstruction Lower CT Radiation Dose: Evaluation of 15000 Examinations.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13044476.html