INBDE (Integrated National Board Dental Examination) Practice Exam

Intensifying screens are made of what?

1. Silver halide crystals

2. Photographic gelatin

3. Rare-earth elements

4. Bismuth salts

The correct answer is: Rare-earth elements

Intensifying screens are made of rare-earth elements, typically gadolinium or lanthanum, mixed with a binder material such as plastic, cellulose, or glass. These elements are used in intensifying screens because they have a high atomic number, which allows them to absorb more x-rays and intensify the image produced. Option A, silver halide crystals, is incorrect because these are typically used in the film emulsion rather than the intensifying screen. Option B, photographic gelatin, is also incorrect as it is used to hold the silver halide crystals in place in the film emulsion. Option D, bismuth salts, are not typically used in intensifying screens as they do not provide the same level of x-ray absorption as rare-earth elements. Therefore, option C, rare-earth elements, is the correct answer as they are specifically chosen for their ability to intensify x-rays in medical imaging.