| Popis: |
LIKE THE OTHER factors involved in radiography, the kilovoltage factor has been the subject of almost continuous study. The equipment available has always had a profound influence on the voltage range over which routine work could be done. At no time has there been any universally accepted technic for any single part of the body. Personal preference and experience have in general been the dominant factors in determining the kilovoltage used in most laboratories. In its infancy radiography was limited, by the generators and tubes available, to relatively low voltages. With the advent of the alternating current transformer, mechanical rectifiers, and the Coolidge tube, the kilovoltage was increased. The universal type, fine-focus Coolidge tube was frequently used at 100 kv.p. for radiography of the lumbar spine and the chest in large patients. When the radiator-type tube became available, the voltage was limited to 85 kv.p., a limitation willingly accepted because of the improved definition made possible by... |
