S. Meeson et al., Procedure for quantitatively assessing automatic exposure control in mammography: a study of the GE Senographe 600 TS, BR J RADIOL, 74(883), 2001, pp. 615-620
Citations number
5
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
The correct operation of a mammography system's automatic exposure control
system (AEC) is essential if mammograms are to be produced with a suitable
film exposure. A methodology has been developed that allows the performance
of the AEC to be assessed quantitatively using clinical films. By digitizi
ng mammograms, the mean optical density (OD) in the main breast region and
in a region of interest corresponding to the position of the AEC detector a
re evaluated for each film, together with the area of the main breast. Usin
g these data it is possible to determine the relationships between the mean
OD, breast size and AEC detector position. The performance of the AEC on a
GE Senographe 600 TS system was investigated. The study found that there i
s a tendency to underexpose smaller breasts, i.e. with an area less than ap
proximately 4000 mm(2). This is equivalent to a compressed tissue width of
approximately 60-80 mm. The difference in mean OD between the mammograms of
small and large breasts was up to 0.7 OD. Provided the sensitive area of t
he AEC detector is known, this method of assessing AEC performance can be u
sed with any mammography system.