ANALISIS PENGARUH KETIDAKTAJAMAN GEOMETRI, PERGERAKAN DAN SCREEN TERHADAP PENGABURAN DAERAH TEPIAN FILM RADIOGRAFI

Abstract

This study entitled analysis of geometric unsharpness, moving, and screen on the edge blurring of radiograph film periphery was conducted by purpose to determine measurement of penumbra on this peripheral image of this geometric unsharpness, movement and screen. Besides, it was also aimed to determine predominantly causes of unsharpness among three unsharpness types and to determine way of lowering unsharpness on periphery by using focal spot and speed screen. This study was conducted by measuring penumbra and its density in collimation and object limits on radiography film, in various FFDs (70, 80, and 90 cm), various OFDs (0. 5, and 10 cm), various focal spots (0.5 and 2 mm), various speed screens (medium and fast screen) and various movements (movement and motionless objects). The measurement result has shown that penumbra measures was getting bigger for smaller FFD value, higher OFD, higher focal spot, speed film fast and movement objects. The predominantly factors which causing unsharpness on are of film periphery was geometric factors with various focal spot. Such caused of unsharpness on area offal periphery can be lowered by using moving factor and medium speed screen.