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Biomedical subjects

L A Maslov

Publications and source records attributed to L A Maslov.

11 recordsLinked to original sources
PubMedDate not supplied

[Sensitometric characteristics of medical roentgenographic and fluorographic films. Sensitivity of the amplifying screens combined with a film].

Factors affecting the degree of sensitivity of roentgenographic and radiofluorographic films and of their combinations with fluorescent screens are considered. A method of films exposure with a roentgenosensitometer permitting it to determine the sensitivity in conditions closely approaching the ones used in practice and corresponding to the minimum of the isoopaque is suggested. A way for determining the sensitivity of films in m2-mJ1 and lx-1-c-1 is indicated. Numerical values for the sensitivity of the films and their combinations with the screens are given. It is shown that with Eef = 38 keV, T = 20 degrees C, exposure time of 0.4--1 sec and optical density 1.00 over general focusing the lower limit of the X-ray RM-1film sensitivity to the light of CaWO4-screens is 38 m2-mJ-1 and of the fluorographic film Pphi-3 to the light of the Zn0-68Cd0-32S--Ag-screens -- 14.6 m2-mJ-1 or 30 lx-1-c-1.

Fluoroscopy↗
PubMedDate not supplied

[A comparison of various methods of x-ray sensitometry].

Three methods of roentgen sensimetry have been compared: the wedge method based on using the stepped wedge, the Moscow Radiation and Roentgenology Research Institute method consisting in the time-modulation of the exposure by means of a lead diaphragm and revolving cassette with screens and film, and the method, according to which the dose is modulated by changing the distance from the source of irradiation to the cassette. The exposure conditions have been selected in order to achieve the best coordination of the results obtained by all the three methods. The minimal sensitivity of the combination of the medium amplification screens of ZY-B2A type with film PM-1 is about 1000P-1. For a more complete characteristic of the important properties of the roentgenographic films it is necessary in addition to determining the sensitivity, gamma and medium gradient to measure the parameters determining the graininess of the film and the transmission of the screen light by its emulsion layer.

Technology, Radiologic↗