Xray Film

Question 1

What is replacing film in X-ray?

Answer 1

Digital systems

Question 2

Film

Answer 2

Creates a hard copy radiographic image that must be stored in envelopes and warehoused on shelves

Question 3

Digital images

Answer 3

soft copy images that can be stored electronically in a PACS

Question 4

Base

Answer 4

Used to support the other portions of the film in order to form the image

Question 5

Modern film

Answer 5

consists of polyester plastic that is 150 – 200 μm (0.006 to 0.008”) in thickness.

Question 6

Glass

Answer 6

The original film base material were glass plates, first marketed by John Carbutt in 1896.

These films had a single emulsion placed upon them

Question 7

What are some problems with glass plate films?

Answer 7

1. Low maximum density
2. Fragile
3. Weight
4. Cost

Question 8

Cellulose Nitrate

Answer 8

Soft, lightweight and flexible, much like modern polyester plastic.
Extremely flammable

Question 9

Cellulose triacetate

Answer 9

Marketed as safety film since it did not have the flammability of cellulose nitrate
Easily torn

Question 10

Polyester

Answer 10

Virtually indestructible and does not decompose over time

Question 11

Adhesive sub layer

Answer 11

Usually gelatin to hold the emulsion to the base

Question 12

Emulsion

Answer 12

Image forming part of the film. It is made up of:
1. Silver halide crystals - microscopic crystals that are 1 micro mill across usually flat
2. Suspending agent - used to suspend the silver halide crystals across emulsion
3. Sensitivity specks or development centers - impurities of silver unfixed added to the silver halide crystals, act as electron traps

Question 13

What are the 2 thickness options available for emulsion?

Answer 13

1. Single emulsion film - used for fine detail studies such as mammography
2. Duplitized emulsion film

Question 14

Disadvantage of single emulsion films

Answer 14

Higher dose of radiation is required

Question 15

Duplitized emulsion layer

Answer 15

film with an emulsion layer on both sides of the base.

Question 16

Disadvantage of duplitized film

Answer 16

Loss of detail occurs due to parallax effect

Question 17

Parallax effect

Answer 17

Same structure is visualized at 2 different points
To minimize effect, emulsion layer needs to be kept as thin as possible

Question 18

Cross over effect

Answer 18

Light from one screen crosses over to emulsion layer on the opposite side
Some manufacturers add material to adhesive layer to prevent cross over

Question 19

Super coating

Answer 19

Gelatin coating to protect the emulsion during film handling and processing

Question 20

Speed or sensitivity

Answer 20

How much exposure to the film does it take to produce a certain level of optical density
Slower film speed require more mAs
50 - slow speed
100- Average speed
200 - Fast speed

Question 21

Latitude

Answer 21

The range of exposures that will produce a diagnostic image
Narrow latitude - smaller amount of radiation

Question 22

Contrast

Answer 22

The range of gray shades that the film is able to record and display
Latitude and contrast are inversely related
Wide latitude has low contrast

Question 23

Gurney-Mott animation

Answer 23

Halide ions concentrate on the outer surface of the crystal, while silver is trapped on the inside

Question 24

Screen film

Answer 24

Designed to be used with cassettes that have intensifying screens

Question 25

Spectral matching

Answer 25

Screen must emit the same color to form a radio graphic image

Question 26

Blue-violet sensitive

Answer 26

sensitive only to light in the blue-violet portion of the color spectrum.

Question 27

Orthochromatic or ortho G - green sensitive

Answer 27

Green sensitive film

Question 28

Pan chromatic

Answer 28

Sensitive to all colors of light

Question 29

Non-screen or direct exposure film

Answer 29

Duplitized film that has a much thicker emulsion than screen film in order to absorb more xrays

Question 30

Dry laser film

Answer 30

Used with dry laser printers to print hard copies of digital images

Question 31

Industrial film

Answer 31

This is a single emulsion direct exposure film
Used to obtain very fine detail because there is no parallax effect

Question 31

Industrial film

Answer 31

This is a single emulsion direct exposure film
Used to obtain very fine detail because there is no parallax effect

Question 32

Film facts

Answer 32

1. Film deteriorates with age
2. Film is sensitive to heat and humidity
3. Film is sensitive to electrical static
4. Film is very sensitive to pressure
5. Film is sensitive to chemical fumes
6. Film is sensitive to virtually all types of ionizing radiation and white light and should be shielded
7. Film can be damaged by fingerprints, scratches, bending

Question 33

Tree static artifact

Answer 33

Caused by removing film from cassette too rapidly

Question 34

Crown artifact

Answer 34

Caused by pulling film from the film bin too rapidly

Question 35

Smudge artifact

Answer 35

Caused by excessive static discharge over a large area