AMBER: FOR CHEST, LARYNX AND ABDOMINAL RADIOGRAPHY

Abstract

Conventional radiography is limited by the small useful exposure range of radiographic film. The wide variation in absorption thickness of different parts of the body results in areas of under-and over exposure. An advanced multiple beam equalization system, AMBER, controls local exposure delivered to the film. The system has a row of 20 modulators in front of the x-ray tube, each able to change the height of the local slit beam during scanning. Changes are made in response to measurements from a linear detector array in front of the film cassette. This array consists of 20 individually functioning detectors coupled through electronic feedback loops to the 20 modulators. A scan is obtained in 0.8 second with a local exposure time of approximately 50 msec. AMBER results in radiographs with sig- nificantly improved exposure of the mediastinum without overexposure of the lungs. Originally, this system was aimed to use for the chest radiography, however, abdominal radiography and laryngeal radiography was used by us to illustrate the images produced by this machine.