Effect of film graininess and geometric unsharpness on image quality in fine-detail skeletal radiography.

Three direct x-ray films and three geometric conditions were used to study the effect of noise and sharpness on high resolution radiography of the hand. The Wiener spectrum of film graininess and the MTF of geometric unsharpness were measured. Radiographs of a wire mesh and a hand phantom, together with the Wiener spectra and MTFs, led to the following conclusions regarding fine-detail skeletal radiography, as currently employed: 1) bone structure detectable in vivo does not show minute structural detail; 2) the technique is primarily noise-limited; 3) the use of better geometry or finer grain film for improving resolution or noise is of limited practical value, whereas the use of poorer geometry or more noisy film results in appreciable degradation of skeletal images; and 4) the present standard technique for in vivo radiography of the hand, therefore, may be very nearly optimal for clinical applications.