Investigation of the performance of digital mammographic X-ray equipment: determination of noise equivalent quanta (NEQQC) and detective quantum efficiency (DQEQC) compared with the automated analysis of CDMAM test images with CDCOM and CDIC programs.

Purpose: The purpose of this study was to determine the values for noise equivalent quanta, detective quantum efficiency, modulation transfer function, noise power spectrum, and the values for the parameters for automated CDMAM test phantom analyses required to achieve satisfactory quality of digital mammograms.

Materials And Methods: During the course of tests according to PAS 1054 (8 CR and 12 DR systems), test images were made with a test phantom insertion plate containing two lead edges in nearly horizontal and vertical directions. Only original data were processed with a program that was developed at the Cologne University of Applied Sciences (FH-Köln).

[Investigation on the 3 D geometric accuracy and on the image quality (MTF, SNR and NPS) of volume tomography units (CT, CBCT and DVT)].

Purpose: The study aims at investigating how far image quality (MTF and NPS) differs in between CT, CBCT and DVT units and how far the geometrical 3 D accuracy and the HU calibration differ in respect to surgical or radio therapeutic planning.

Materials And Methods: X ray image stacks have been made using a new designed test device which contains structures for measuring MTF, NPS, the 3 D accuracy and the Hounsfield calibration (jaw or skull program). The image stacks of the transversal images were analyzed with a dedicated computer program.

[Results of an automatic evaluation of test images according to PAS 1054 and IEC 6220-1-2 on different types of digital mammographic units].

Aim: To test whether image processing methods are suitable for detecting differences in the image quality of digital mammography units and whether the methods are more sensitive than visual test methods like the evaluation of CDMAM test images.

Methods: Test images according to PAS 1054 were acquired with CR and DR systems and analyzed automatically. Only parameters were used that are obligatory for calculating the detective quantum efficiency (DQE), the noise power spectrum (NPS), the spatial resolution (MTF, modulation transfer function), and the averaged glandular dose (AGD).

[Comparison of two automatic evaluation methods on Images of the CDMAM test phantom].

Purpose: To test the sensitivity of automatic methods for evaluating CDMAM test images with respect to noise.

Materials And Methods: CDMAM test images were analyzed with two computer programs. The images were made with different tube loads [mAs].

[Bavarian mammography screening: results of consistency tests in X-ray units over three months].

Purpose: To find out whether the quality requirements in daily, weekly or monthly tests of the "European protocol for the quality control of the physical and technical aspects of mammographic screening (EPQC)" can be maintained when screening the population of a large area. Furthermore, to check the specific tolerances of different test positions given by the EPQC for redundancy and statistical correlation.

Materials And Methods: Daily test images were obtained with an additional exposition of a sensitometric step wedge according DIN 6868 - 2.