Optimization of selective exposure radiography of the chest
A major technical limitation in conventional chest radiography is the mismatch of the x-ray transmission dynamic range with the useful exposure range of a radiographic film when a patient is presented with a uniform incident exposure field. The goal of this project is to develop a faster and more reliable selective exposure system to fabricate and position a compensating filter (or digital beam attenuator, DBA) for clinical use. The essential components of this system include a dose efficient test-image detector, a special purpose field grabber (image memory), a custom made fast printer, a transport channel, and a computer. The fabrication process begins with acquisition of a 64 x 64 format low-dose patient image which undergoes corrections for detector nonuniformity and scatter. The corrected data after log transformation are used to calculate thickness of filter material needed to compensate for the image dynamic range. Using this thickness information the computer controls the printer which fabricates as attenuator by overprinting multiple layers of cerium oxide on a 35 mm film substrate. Although the images are acquired in a 64 x 64 format, the attenuator is constructed in a dithered 16 x 16 format using a special algorithm. After fabrication, the attenuator is automatically conveyed through the transport channel and is positioned in the x-ray beam between the collimator and x-ray tube before the final compensated radiograph is taken.
- Research Organization:
- Wisconsin Univ., Madison (USA)
- OSTI ID:
- 7186230
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
62 RADIOLOGY AND NUCLEAR MEDICINE
BIOMEDICAL RADIOGRAPHY
BODY
BODY AREAS
CHEST
DIAGNOSTIC TECHNIQUES
DIAGNOSTIC USES
ELECTROMAGNETIC RADIATION
IMAGE PROCESSING
IONIZING RADIATIONS
MEDICINE
NUCLEAR MEDICINE
OPTIMIZATION
PATIENTS
PROCESSING
RADIATIONS
RADIOLOGY
USES
X RADIATION