I assume it was used for photographing X-ray luminescent screens in medical examinations.
In a way it was the intensifyer-foil system took apart:
Film (for image storage) and foil (for sensing X-rays) were not sandwitched in a filmholder, but the screen was freely visible and the film was exposed by using a camera (with high speed lens).
This enabled the physician to use the foil (in this case stiff screen) as a monitor.
Even after omitting direct vision of the screen, such screen photography was more economic than exposing sheets in the 1/1 scale, allowing for mass-screening.
Most probably that film was specially sensitized for the radiation of that screen.
Though I'm a bit surprised by the film having had to be stored in refrigerator.
