Comparison of Image Quality Obtained with Optical and Radiographic Magnification Techniques in Fine-Detail Skeletal Radiography: Effect of Object Thinkness1

High-resolution radiography may be done using either optical or radiographic magnification. In the former technique, Industrial Type M film was used without screens and the image was viewed with 4–10× optical magnification. In the latter technique, RP film was used with Detail screens and 4× geometric magnification together with a microfocus x-ray tube having a nominal focal spot size of 50 µm. The imaging properties of both techniques were evaluated by means of H & D curves, modulation transfer functions, and Wiener spectra. It was found that for thin objects such as the hand, optical magnification provides better bone images than radiographic magnification; whereas for thicker parts such as the knee, radiographic magnification is superior.