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

RATIONALE AND OBJECTIVE. To optimize screen-film combinations for equa lization radiography (advanced multiple beam equalization radiography [AMBER]), five different film-screen-technique combinations were compa red by receiver operating characteristics study of simulated interstit ial disease. MATERIALS AND METHODS. The Ortho C-Lanex Regular and the Insight Thoracic Imaging HC system were compared in conventional noneq ualized technique; T-Mat G-Lanex Regular and T-Max L-Lanex Regular wer e 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 techn ique. Seven observers scored the presence of interstitial disease in e ach of the quadrants on a 5-point scale following receiver operating c haracteristic methodology. RESULTS. The highest performance was found with the experimental film-screen-AMBER combination (A(z) = 0.92) and the lowest with the T-Mat L-Lanex Regular-AMBER combination (A(z) = 0. 83) and the Insight Thoracic Imaging HC system-conventional combinatio n (A(z) = 0.85), T-Mat L-Lanex Regular-conventional ranked second (A(z ) = 0.90) while T-Mat G-Lanex Regular-conventional (A(z) = 0.89), T-Ma t L-Lanex Regular-AMBER (A(z) = 0.88) and Ortho-C-Lanex Regular-conven tional (A(z) = 0.87) scored lower. CONCLUSION. Higher contrast films i n AMBER improve diagnostic performance, whereas a loss of information is found if the AMBER system is combined with lower contrast films.