The readout thickness versus the measured thickness for a range of screen film mammography and full-field digital mammography units.
OBJECTIVE
To establish a simple method to determine breast readout accuracy on mammography units.


METHODS
A thickness measuring device (TMD) was used in conjunction with a breast phantom. This phantom had compression characteristics similar to human female breast tissue. The phantom was compressed, and the thickness was measured using TMD and mammography unit readout. Measurements were performed on a range of screen film mammography (SFM) and full-field digital mammography (FFDM) units (8 units in total; 6 different models/manufacturers) for two different sized paddles and two different compression forces (60 and 100 N).


RESULTS
The difference between machine readout and TMD for the breast area, when applying 100 N compression force, for nonflexible paddles was largest for GE Senographe DMR+ (24 cm × 30 cm paddle: +14.3%). For flexible paddles the largest difference occurred for Hologic Lorad Selenia (18 cm × 24 cm paddle: +26.0%).


CONCLUSIONS
None of the units assessed were found to have perfect correlation between measured and readout thickness. TMD measures and thickness readouts were different for the duplicate units from two different models/manufacturers.
Oslo and Akershus University College of Applied Sciences, Department of Radiography and Dental Technology, St. Olavs plass, NO-0130 Oslo, Norway. ingrid-helen.ryste-hauge@hioa.no
Ingrid H R
IH
Hauge
Peter
P
Hogg
Katy
K
Szczepura
Paul
P
Connolly
George
G
McGill
Claire
C
Mercer
D001940:Breast / Q000502:physiology*; D003720:Densitometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D008327:Mammography / Q000295:instrumentation*; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014962:X-Ray Film