Optimization of chest films of equalization radiography (advanced multiple beam equalization radiography). Comparison by means of a receiver operating characteristic study of simulated nodular interstitial disease.
OBJECTIVE
To optimize screen-film combinations for equalization radiography (advanced multiple beam equalization radiography [AMBER]), five different film-screen-technique combinations were compared by receiver operating characteristics study of simulated interstitial disease.


METHODS
The Ortho C-Lanex Regular and the Insight Thoracic Imaging HC system were compared in conventional nonequalized technique; T-Mat G-Lanex Regular and T-Max L-Lanex Regular were compared in conventional, nonequalized, and AMBER technique; and an experimental high-contrast, low-noise, near-zero crossover film-screen combination was compared in AMBER technique. Interstitial disease was simulated by superimposing birdseed on the back of a humanoid phantom. Twenty-five posterior-anterior radiographs were made with each technique. Seven observers scored the presence of interstitial disease in each of the quadrants on a 5-point scale following receiver operating characteristic methodology.


RESULTS
The highest performance was found with the experimental film-screen-AMBER combination (Az = 0.92) and the lowest with the T-Mat L-Lanex Regular-AMBER combination (Az = 0.83) and the Insight Thoracic Imaging HC system-conventional combination (Az = 0.85). T-Mat L-Lanex Regular-conventional ranked second (Az = 0.90) while T-Mat G-Lanex Regular-conventional (Az = 0.89), T-Mat L-Lanex Regular-AMBER (Az = 0.88) and Ortho-C-Lanex Regular-conventional (Az = 0.87) scored lower.


CONCLUSIONS
Higher contrast films in AMBER improve diagnostic performance, whereas a loss of information is found if the AMBER system is combined with lower contrast films.
Schultz Kool
L J
LJ
Department of Diagnostic Radiology, University Hospital Leiden, Leiden, The Netherlands.
van Proosdij
M
M
van Metter
R
R
Vrooman
H A
HA
Aarts
N J
NJ
Shaw
P M
PM
Obermann
W R
WR
Heijboer
R J
RJ
Memel
D S
DS
Oestmann
J W
JW
D006801:Humans; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging*; D008961:Models, Structural; D012372:ROC Curve; D013902:Radiography, Thoracic / Q000379:methods*; D014963:X-Ray Intensifying Screens