Image quality measurements and metrics in full field digital mammography: an overview

Abstract

This paper gives an overview of test procedures developed to assess the performance of full field digital mammography systems. We make a distinction between tests of the individual components of the imaging chain and global system tests. Most tests are not yet fully standardised. Where possible, we illustrate the test methodologies on a selenium flat-panel system.

Does digital mammography in a decentralized breast cancer screening program lead to screening performance parameters comparable with film-screen mammography?

“…For DM, a type testing procedure has been introduced: only systems that successfully passed the type test protocol can be presented for an acceptance test [10]. The type test protocol copies the European Guidelines for physicaltechnical quality assurance (QA) and adds a radiological evaluation on 25 examinations to assess stability of processing and the global appearance of the images [11,12]. Next, the systems in all the participating mammography units have to pass an acceptance test with all the criteria of the European protocol and a set of ten images is used to verify the transition of the images from the first center to the CBU center and to verify the global image quality and visualization on the work station in the center for second reading.…”

Figure of Image Quality and Information Capacity in Digital Mammography

“…The normalized noise power spectrum (NNPS) is often used to compare the noise properties of different imaging systems [30]. NNPS [29] is defined as $\begin{array}{c}\text{NNPS}\left(f\right)=\frac{\text{NPS}\left(f\right)}{{\left(G·X\right)}^{\mathrm{2}}},\end{array}$ where X is the air Kerma in μGy .…”

“…The latter provides an index of the signal-to-noise ratio (SNR) associated with the diagnostic value of a medical image [29, 32, 33]. NEQ can be written as follows [32, 34–36]: $\begin{array}{c}\text{NEQ}\left(f\right)=\frac{\text{SPS}\left(f\right)}{\text{NPS}\left(f\right)}.\end{array}$ …”

Digital mammography: what do we and what don’t we know?

“…This can be used in clinical practice, where integrated digital mammography systems with a high DQE are usually operated at a mean glandular dose 20-30% lower than that of film-screen mammography [16][17][18]. Since the DQE of a digital system is difficult to measure in a standardized manner and may depend on a variety of factors such as Xray beam quality and detector dose [19], acceptance testing for digital mammography systems is usually achieved by assessing the contrast-detail resolution of a system with certain phantoms such as the CDMAM phantom [14,20]. However, contrast-detail phantoms such as the CDMAM phantom showing objects on a uniform background may not be ideal to predict the performance of a system in clinical practice.…”