Multiple-energy tissue-cancellation applications of a digital beam attenuator to chest radiography

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5618879

Dobbins, III, J T

The digitally-formed primary beam attenuator (DBA) spatially modulates the x-ray fluence incident upon the patient to selectively attenuate regions of interest. The DBA attenuating mask is constructed from CeO/sub 2/ powder by a modified printing technique and uses image information from an initial low-dose exposure. Two tissue-cancellation imaging techniques are investigated with the DBA: (1) energy-dependent information is used to form a beam attenuator that attenuates specific tissues in the primary x-ray beam for tissue-cancelled film radiography; (2) the beam attenuator is used to improve image signal-to-noise and scattered radiation properties in traditional energy-subtraction tissue-cancellation imaging with digital detectors. The tissue-cancellation techniques in the primary x-ray beam were capable of adequately removing either soft-tissue or bone from the final compensated film radiograph when using a phantom with well defined soft-tissue and bone sections. However, when tried on an anthropomorphic chest phantom the results were adequate for cancellation of large soft tissue structures, but unsatisfactory for cancellation of bony structures such as the ribs, because of the limited spatial frequency content of the attenuating mask. The second technique (with digital detectors) showed improved uniformity of image signal-to-noise and a two-fold increase in soft-tissue nodule contrast due to improved scattered radiation properties. The tissue-cancelled images contained residual image contributions from the presence of the attenuating mask, but this residual may be correctable by future algorithms.

• Research Organization: Wisconsin Univ., Madison (USA)
• OSTI ID: 5618879
• Country of Publication: United States
• Language: English

Related Subjects

550602* -- Medicine-- External Radiation in Diagnostics-- (1980-)
62 RADIOLOGY AND NUCLEAR MEDICINE
ATTENUATION
BIOMEDICAL RADIOGRAPHY
DESIGN
DIAGNOSTIC TECHNIQUES
ELECTROMAGNETIC RADIATION
IMAGES
IONIZING RADIATIONS
IRRADIATION DEVICES
MEDICINE
MOCKUP
NUCLEAR MEDICINE
PHANTOMS
RADIATIONS
RADIOLOGY
SIGNAL-TO-NOISE RATIO
STRUCTURAL MODELS
X RADIATION