Film-screen sharpness in complex motion tomography.

R E Wayrynen; R S Holland; R P Schwenker

doi:10.1097/00004424-197703000-00017

Home/Archive/PubMed

PubMed · 852953

Film-screen sharpness in complex motion tomography.

R E Wayrynen·R S Holland·R P Schwenker

View original source ↗Export metadata ↓

Abstract

An unsharp radiologic image is created in tomography by the combined motion of the x-ray tube and the film-screen cassette. This image is generally recorded at angles other than normal to the film-screen plane. A metbd for determining the influence of this recording angle on film-screen sharpness is described. The method involves imaging an edge target at various angles between the x-ray beam and the film-screen plane. The MTF is then calculated from the edge images. The effect of film-screen sharpness and quantum noise on subjective image quality in temporal bone tomography is discussed.

Explore related subjects

Technology, Radiologic Temporal Bone Tomography, X-Ray Journal Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

R E Wayrynen, R S Holland, R P Schwenker. Film-screen sharpness in complex motion tomography.. https://doi.org/10.1097/00004424-197703000-00017

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1992

Re: Film processing.

Explore the source record for details and available documents.

Technology, Radiologic↗

PubMed1992

Automatic film processing: analysis of 9 years of observations.

A survey method known as the sensitometric technique for the evaluation of processing (STEP) has been used to monitor processing speed of over 2,000 automatic film processors in hospitals, private offices, and mammography facilities since 1981. Analysis of data obtained through this program revealed underprocessing at 33% (76 of 231) of observed hospitals in 1987, 7% (13 of 179) of mammography facilities in 1988, and 42% (101 of 241) of private practices in 1989. Underprocessing at mammography facilities decreased from 18% (25 of 139) in 1985, which was contrary to the trend in hospitals. The consequence of underprocessing is higher radiation exposure and a degradation in film contrast. Evaluation of automatic film processors is a necessary part of any comprehensive evaluation of a diagnostic radiography facility. The STEP procedure was designed only as a field survey test; to ensure optimal conditions for obtainment of diagnostic quality radiographs, facilities should perform quality assurance evaluations of their processing equipment and verify that processing recommendations of manufacturers are being followed.

Technology, Radiologic↗

PubMed1979

Quantity of tomographic blurring.

A spiral tomographic movement gives rise to a lower quantity of blurring than does a circular movement with the same tomographic angle since in the former the focus comes nearer to the central point. It has been demonstrated that the transfer function may be used to express the quantity of blurring for different tomographic movements. For the sake of convenience the blurring quantity for every type of spiral movement may be expressed in terms of the tomographic angle of a circular movement giving rise to the same transfer function.

Technology, Radiologic↗