Question 1

What is the term generally used to describe the emission of light from a substance as the result of external stimulation?

Accepted Answer

Luminescence is the general term that describes the emission of light in response to exposure to x-rays.

Question 2

What is measured by comparing an exposure without an intensifying screen to an exposure with an intensifying screen?

Accepted Answer

The intensification can be calculated by dividing the amount of mAs needed without intensifying screens by the amount needed with screens.

Question 3

What is achieved when the color of light emitted by an intensifying screen matches the color of light a film responds to?

Accepted Answer

Spectral matching occurs when the color of light emitted from the intensifying screen matches the film's color sensitivity.

Question 4

What kind of radiographic film is designed to respond specifically to x-radiation and not to the light emitted from intensifying screens?

Accepted Answer

Direct exposure film, seldom used in modern radiography due to the large amount of exposure needed, is designed to be most sensitive to the x-radiation.

Question 5

What are the physical imperfections in the emulsion layer of radiographic film called?

Accepted Answer

Sensitivity specks are deliberate imperfections in the lattice of the emulsion layer and will serve as the latent image center.

Question 6

Increasing the thickness of the intensifying screen phosphor layer:

Accepted Answer

Using a thicker phosphor layer in an intensifying screen will result in a faster speed screen, less recorded detail, and less patient exposure (due to the decreased mAs needed to maintain density).

Question 7

What is the term specifically used to describe the emission of light during stimulation only?

Accepted Answer

Fluorescence is the emission of light only while being exposed to x-rays. This is the type of luminescence that is desired in intensifying screens.

Question 8

Which layer of the intensifying screen is closest to the film?

Accepted Answer

The protective layer of the intensifying screen, made of plastic and used to protect the phosphor layer, is located closest to the film.

Question 9

How much of the x-ray beam do calcium tungstate phosphors absorb?

Accepted Answer

Calcium tungstate intensifying screen phosphors absorb only 30% to 40% of the x-ray beam.

Question 10

Which layer of the intensifying screen is the furthest from the film?

Accepted Answer

The base of the intensifying screen, made of polyester or cardboard, is located furthest from the film.

Question 11

What is the effect of the presence of a reflective layer within the intensifying screen?

Accepted Answer

Using a reflective layer in an intensifying screen will result in a faster speed screen, less recorded detail, and less patient exposure (due to the decreased mAs needed to maintain density).

Question 12

What is the purpose of the intensifying screen?

Accepted Answer

The purpose of an intensifying screen is to reduce the exposure to the patient, due to the action of the x-rays being intensified.

Question 13

How can you describe a noisy image?

Accepted Answer

A noisy image is an image with significant quantum mottle.

Question 14

What influences the speed of radiographic film?

Accepted Answer

Both the amount and size of the silver halide crystals affect film speed. The more and larger the crystals, the faster the film.

Question 15

Which of the following may influence the presence of quantum mottle?

Accepted Answer

Anything that affects the amount of light or x-rays needed to produce an image will affect quantum mottle. The less the amount of light or x-rays needed, the greater the amount of quantum mottle.

Question 16

When a film has the emulsion coated on both sides of the base versus one side of the base, the film is referred to as:

Accepted Answer

A double emulsion film has a layer of silver halide and gelatin coated on both sides of the base.

Question 17

What is the term specifically used to describe the emission of light during and after external stimulation?

Accepted Answer

Phosphorescence is the emission of light during and after being exposed to x-rays. Also called lag or afterglow, this is not the type of luminescence that is desired in intensifying screens.

Question 18

What is the outermost layer of radiographic film called?

Accepted Answer

The supercoat is the outermost layer of the film and serves to protect the emulsion layer from damage.

Question 19

What is the term used to describe the color of light to which a radiographic film is sensitive?

Accepted Answer

Spectral sensitivity describes the color of light to which a film is most sensitive.

Question 20

How much of the x-ray beam do rare earth phosphors absorb?

Accepted Answer

Rare earth intensifying screen phosphors absorb about 60% of the x-ray beam.

Quiz 7: Image Receptors