A comparison of mammographic phantoms

It is important to establish and maintain high standards of image quality in mammography in order to detect breast cancer at an early stage. A commonly used method of assessing image quality in mammography is to use test phantoms. This paper reports a comparison of seven mammographic phantoms. These are the Ackermann (DuPont, Stevenage), Barts (White and Tucker), CIRS XI (Computerized Imaging Reference Systems, USA), Leeds TOR(MAX) and Leeds TOR(MAM) (Faxil, Leeds), Newcastle, and RMI 152 (Gammex RMI, Nottingham). These phantoms were assessed on the detectability of the various details and bar patterns contained in each. Step wedges and simulated anatomical features were not assessed. The effect on phantom images of changes in contrast, caused by changing tube potential from 25 kV to 35 kV, and of changes in resolution, caused by different focal spot sizes and by different magnifications, were investigated. It was deduced from the results of this study that there was no single phantom which was clearly superior to all the others. The three phantoms which had the greatest sensitivity to changes in imaging parameters were the Leeds TOR(MAM), the Newcastle and the Ackermann (DuPont) phantoms.