Medichrome Film as an Alternative to Silver-Free Recording Systems

Self Cite

In phantom experiments a number of intensifying screens were tested as regards their usefulness for angiography. Film speed was adjusted so as to make possible a constant radiographic exposure despite screen speeds varying by a factor of 3. Thus, screen unsharpness varied considerably. However, it was of no practical importance as long as the radiographic exposure was kept constant. This observation indicates that the modulation transfer function is of limited value in differentiating between screens for high-speed angiography. Likewise, film contrast was of little significance for image quality, as compared with radiographic exposure to the intensifying screens.

Section: Discussionmentioning

confidence: 99%

Choice of Screens in High-Speed Angiography

Reichmann¹,

Astrand²,

Lundin

1979

Self Cite

Influence of Microscopic Mottle on the Definition of Small Image Details

Selin¹,

Reichmann

1979

Self Cite

By a special technique of enlarging films, a microscopic mottle caused by quantum fluctuations was demonstrated. It was found to affect depiction of small details in such a way as to suggest that it would be of importance for determining resolution capacity, especially in high-speed radiography. Thus, the modulation transfer function appears not to be the only factor determining radiographic resolution. The resolution of high-speed screens may be improved if the film speed is reduced, which leads to a diminished microscopic mottle.

Storage and Display of Information in Roentgen Films

Reichmann¹,

Strid²,

Lundin³

1980

Self Cite

Roentgen images of high density, without actually being overexposed, tend to leave small details of low contrast unrecorded. Still, these details may be reproduced by the same film if the density is lower, even if the gamma value is kept constant. The present report is concerned with how information is stored in the film and the information stored is displayed to the inspecting eye. It appears that films of high density contain information which is invisible, so that the disappearance of image details to a certain extent reflects a defect of display.