How are indirect exposure films primarily exposed during radiography?

Indirect exposure films are primarily exposed by fluorescent light from a phosphor screen. This process involves a photostimulable phosphor that converts x-rays into visible light. When x-rays strike the phosphor layer, it releases visible light in response. The emitted light then exposes the film, allowing for the creation of an image.

This method is advantageous because it allows for lower doses of radiation to be used compared to direct exposure films, which require a direct beam of x-rays. Indirect exposure films are commonly used in digital radiography systems, where the phosphor screen plays a critical role in capturing the radiation and converting it to a form that can be recorded and processed. The ability to use fluorescent light not only enhances the image quality but also improves safety by reducing the amount of radiation the patient is exposed to during the imaging process.