RSNA 2016

Abstract Archives of the RSNA, 2016


PH249-SD-WEA4

Framework for Objective and Fully Automated Image Quality Control of Dedicated Breast CT Systems

Wednesday, Nov. 30 12:15PM - 12:45PM Room: PH Community, Learning Center Station #4



Christian Steiding, PhD, Erlangen, Germany (Presenter) Employee, CT Imaging GmbH
Daniel Kolditz, PhD, Erlangen, Germany (Abstract Co-Author) Employee, CT Imaging GmbH
Veikko Ruth, MSc, Erlangen, Germany (Abstract Co-Author) Nothing to Disclose
Ferdinand Lueck, DIPLPHYS,PhD, Erlangen, Germany (Abstract Co-Author) Employee, CT Imaging GmbH
Willi A. Kalender, PhD, Erlangen, Germany (Abstract Co-Author) Founder, CT Imaging GmbH; CEO, CT Imaging GmbH
PURPOSE

Dedicated breast CT (BCT) represents an emerging 3D imaging modality that has significant potential for breast cancer detection and diagnosis; the first BCT system has recently been granted FDA approval. As for all new tomographic imaging devices, the conformance of system characteristics with specifications needs to be checked on a regular basis, but to date there is no consensus on acceptance and constancy testing for image quality (IQ) in BCT. The aim of this work was to introduce and validate a quality assurance (QA) framework for objective and easy-to-use IQ control of BCT scanners.

METHOD AND MATERIALS

A cylindrical QA phantom, with a diameter of 14 cm, a height of 10 cm, made of water-equivalent plastic, was chosen. Various test inserts are embedded in this phantom to determine the desired IQ parameters. Noise by means of the standard deviation and the noise power spectrum as well as uniformity are determined in homogeneous phantom compartments located at different axial positions. Special inserts providing defined CT values allow for assessing image contrast and CT value accuracy. For fully volumetric evaluation of high-contrast spatial resolution, the 3D modulation transfer function of a 12 mm PTFE sphere can be calculated. We implemented an automated detection algorithm for the proposed QA phantom to make automatic and easy-to-use tracking of imaging characteristics feasible. Measurement series were carried out on a photon-counting BCT prototype equipped with a tiled cadmium telluride detector with 0.1 mm pixel size.

RESULTS

Only one scan is required to determine all essential IQ parameters routinely when using the novel QA framework. The interscan variation of repeated measurements was neglectable for all the assessed IQ metrics. Less than 10 s were required for the phantom detection and IQ analysis. The robustness of the proposed QA framework was validated successfully over a period of several months.

CONCLUSION

The proposed QA framework provides quantitative, robust, and fully automated 3D IQ control and is applicable for arbitrary scan protocols. Our study indicates that the concept is suitable for any acceptance and constancy testing in BCT to come.

CLINICAL RELEVANCE/APPLICATION

The proposed framework ensures accurate and reproducible assessment of the stability of objective IQ aspects in BCT and may thereby help to establish QA standards for this emerging imaging modality.