An unexpected artefact with low-contrast high-energy film

Kodak recently introduced new packaging for its X-Omat V verification film, including a label on the exterior of the packet. Patient images taken using the film in an image intensification cassette showed artefacts which appeared to be related to the label. Investigation showed the effect was only observed in conditions of high-Z build-up or backscatter or when the film was used without additional backscatter. The label provides extra build up when in front of the film and an increase in optical density of up to 0.04 units. When the label is on the rear of the film it absorbs backscattered particles, causing a decrease in optical density. It is concluded that X-Omat V film packets with labels are unsuitable for use in imaging cassettes unless they are used in conditions of low-Z build-up. Alternatively the film must be removed from the labelled envelope if it is to be used in high-Z build-up conditions.