Biomaterial Database

Measurement of x-ray image intensifier sharpness in the x-ray department. 1988

J C Le Heron, and J L Poletti

National Radiation Laboratory, Christchurch, New Zealand.

A method is presented for determining the modulation transfer function (MTF) of an image intensifier as it is found in the x-ray department. The image of an edge input into the image intensifier tube is photographed at the television camera port with a high quality camera and the photographic image scanned with a microdensitometer. Densitometric conversion enables the determination of the edge spread function and further calculation produces the line spread function and the MTF. A correction is made for the camera/lens/film/developer response function. Results from the use of the technique on over 25 x-ray image intensifiers in New Zealand hospital x-ray departments are presented and discussed. Most of the image intensifiers had been in use for more than 7 years. The low-frequency drop values were similar to reported values with an average value of 22%, but modulation values at 1 cycle/mm (the average value was 29%) were generally lower than values previously reported, indicating that the sharpness performance in the clinical environment is inferior to claims for new or state-of-the-art intensifiers.

UI	MeSH Term	Description	Entries
D009520	New Zealand	A group of islands in the southwest Pacific. Its capital is Wellington. It was discovered by the Dutch explorer Abel Tasman in 1642 and circumnavigated by Cook in 1769. Colonized in 1840 by the New Zealand Company, it became a British crown colony in 1840 until 1907 when colonial status was terminated. New Zealand is a partly anglicized form of the original Dutch name Nieuw Zeeland, new sea land, possibly with reference to the Dutch province of Zeeland. (From Webster's New Geographical Dictionary, 1988, p842 & Room, Brewer's Dictionary of Names, 1992, p378)
D011856	Radiographic Image Enhancement	Improvement in the quality of an x-ray image by use of an intensifying screen, tube, or filter and by optimum exposure techniques. Digital processing methods are often employed.	Digital Radiography,Image Enhancement, Radiographic,Radiography, Digital,Enhancement, Radiographic Image,Enhancements, Radiographic Image,Image Enhancements, Radiographic,Radiographic Image Enhancements
D011872	Radiology Department, Hospital	Hospital department which is responsible for the administration and provision of x-ray diagnostic and therapeutic services.	Hospital Radiology Department,X-Ray Departments,Department, Hospital Radiology,Department, X-Ray,Departments, Hospital Radiology,Departments, X-Ray,Radiology Departments, Hospital,X-Ray Department,Department, X Ray,Departments, X Ray,Hospital Radiology Departments,X Ray Department,X Ray Departments
D005069	Evaluation Studies as Topic	Works about studies that determine the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies.	Critique,Evaluation Indexes,Evaluation Methodology,Evaluation Report,Evaluation Research,Methodology, Evaluation,Pre-Post Tests,Qualitative Evaluation,Quantitative Evaluation,Theoretical Effectiveness,Use-Effectiveness,Critiques,Effectiveness, Theoretical,Evaluation Methodologies,Evaluation Reports,Evaluation, Qualitative,Evaluation, Quantitative,Evaluations, Qualitative,Evaluations, Quantitative,Indexes, Evaluation,Methodologies, Evaluation,Pre Post Tests,Pre-Post Test,Qualitative Evaluations,Quantitative Evaluations,Report, Evaluation,Reports, Evaluation,Research, Evaluation,Test, Pre-Post,Tests, Pre-Post,Use Effectiveness
D006748	Hospital Departments	Major administrative divisions of the hospital.	Departments, Hospital,Department, Hospital,Hospital Department
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D014963	X-Ray Intensifying Screens	Screens which absorb the energy in the x-ray beam that has penetrated the patient and convert this energy into a light pattern which has as nearly as possible the same information as the original x-ray beam. The more light a screen produces for a given input of x-radiation, the less x-ray exposure and thus shorter exposure time are needed to expose the film. In most film-screen systems, the film is sandwiched between two screens in a cassette so that the emulsion on each side is exposed to the light from its contiguous screen.	Film-Screen Systems, X-Ray,Radiographic Intensifying Screens,Screen-Film Systems, X-Ray,X-Ray Film-Screen Systems,Screens, Radiographic Intensifying,Xray Intensifying Screens,Film Screen Systems, X Ray,Film-Screen System, X-Ray,Intensifying Screen, Radiographic,Intensifying Screen, X-Ray,Intensifying Screen, Xray,Intensifying Screens, Radiographic,Intensifying Screens, X-Ray,Intensifying Screens, Xray,Radiographic Intensifying Screen,Screen Film Systems, X Ray,Screen, Radiographic Intensifying,Screen, X-Ray Intensifying,Screen, Xray Intensifying,Screen-Film System, X-Ray,Screens, X-Ray Intensifying,Screens, Xray Intensifying,System, X-Ray Film-Screen,System, X-Ray Screen-Film,Systems, X-Ray Film-Screen,Systems, X-Ray Screen-Film,X Ray Film Screen Systems,X Ray Intensifying Screens,X-Ray Film-Screen System,X-Ray Intensifying Screen,X-Ray Screen-Film System,X-Ray Screen-Film Systems,Xray Intensifying Screen