Yulia Smal MSc, Presenter: Nothing to Disclose

Wei Chen MEng, Dipl Eng, Abstract Co-Author: Nothing to Disclose

Daniel Kolditz, Abstract Co-Author: Employee, Artemis Imaging GmbH

Bernhard Schmidt PhD, Abstract Co-Author: Employee, Siemens AG

Willi A. Kalender PhD, Abstract Co-Author: Consultant, Siemens AG Consultant, Bayer AG Founder, CT Imaging GmbH Scientific Advisor, CT Imaging GmbH Shareholder, CT Imaging GmbH Founder, Artemis Imaging GmbH CEO, Artemis Imaging GmbH Shareholder, Artemis Imaging GmbH

Software is available for dose estimation in general CT while there is a lack of such tools for pediatric CT covering the age and gender range. We developed a software application with a graphical user interface (GUI) which provides organ and effective dose values in pediatric CT for arbitrary scan parameters based on established voxel phantoms.

The proposed application is based on Monte Carlo (MC) dose calculations performed on the ORNL family of 11 mathematically defined anthropomorphic phantoms representing both genders and different ages (0, 1, 5, 10, 15 years old and adults) with all organs of interest segmented [Cristy M. Rep. ORNL/NUREG/TM-367 1980; Deak et al, Radiology 2010]. Dose contributions from primary and scattered radiation to each voxel was calculated per exposure of each single 5-mm section of the phantoms for a variety of scan parameters, e.g. for 60, 70, 80, 100, 120 and 140 kV. The dose values were tabulated for various scanner types. For any choice of gender and age and arbitrary scan ranges and parameters, the software tool extracts the data from the respective tables and provides organ doses immediately. For validation, results were compared to direct MC calculations using a validated MC tool (ImpactMC, CT Imaging GmbH, Erlangen, Germany).

The GUI allows interactive input of scan parameters and scan ranges for any of the phantoms and provides graphical displays for control. All organ doses and effective doses for ICRP 26, 60, or 103 are displayed without time delay. Values are also compared to dose reference levels which can be updated or created on line by the institution. Evaluations of the effects of variations of scan parameters are easy. E.g., a thorax examination of a 5 year-old child with 120 kV and 40 mAs results in an effective dose of 2.1 mSv and 1.4 mSv for a girl and a boy, respectively, while these are reduced to 1.3 and 0.8 mSv, respectively, for 70 kV and 110 mAs.

The software tool allows fast estimation of dose parameters and relates them to dose reference levels. It offers graphical output and is particularly convenient for teaching purposes.

The GUI-based software covering both genders and the representative ages may be useful in practice and for teaching purposes in pediatric CT.

Smal, Y, Chen, W, Kolditz, D, Schmidt, B, Kalender, W, Fast and On-line Estimation of CT Dose for Pediatric Patients.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034407.html