1. X-ray Equipment
The X-ray machine
Grids
Film and cassettes
Processing

2. X-ray Film
Types of film
Handling of film
Choosing film
 Depends on size, subject, machine

3. X-ray Film
Purpose:
provides permanent record of x-ray image
 Fluoroscopy/ultrasound traditionally transient
 Newer technology allows video capture

4. X-ray Film
Composed of silver halide crystals on
plastic sheet
Crystals interact with:
 Ionizing radiation (including x-rays)
 Visible light
 Pressure
 Bending
 Moisture

5. X-ray Film
Composition
 Similar to photographic film
 Silver halide emulsion on both sides of
polyester base
 Most film bases are blue tinted
Pleasing to the eye

6. X-ray Film
Latent image
 Formed by absorption of light photon by
silver halide crystal
 Energy of photon dislodges an electron
 The electron causes positively charges
silver ions to join into a silver atom

7. X-ray Film
Latent image formation
 Br > Br+ e-
 e- attracts Ag +
 Ag+ Ag+ > Ag atoms

8. X-ray Film Characteristics
Film density
 Measure of film blackening
 Equals log of incident light intensity
divided by transmitted light intensity

9. X-ray Film Characteristics
Film contrast
 Difference between two densities on a
radiograph

10. X-ray Film Characteristics
Film contrast
 Dependant upon:
Characteristic curve of the film
 Film gamma refers to steepest part of
curve

11. X-ray Film Characteristics
Film gamma refers
to steepest part of
curve

12. X-ray Film Characteristics
Film contrast
 Dependant upon:
Film density

13. X-ray Film Characteristics
Film contrast
 Dependant upon:
X-ray exposure
 Higher kVp = greater gamma =
lower contrast (more visible shades
of gray, smaller steps between
grays)

14. X-ray Film Characteristics
High kVp
Higher kVp =
greater gamma =
low contrast
(more visible
shades of gray,
smaller steps)

15. X-ray Film Characteristics
Film contrast
 Dependant upon:
Film processing
 Longer developing times = lower
gamma = less contrast

16. X-ray Film Characteristics
Film latitude
 Exposure range that produces
acceptable densities (0.25-2.0)

17. X-ray Film Characteristics
Film speed
 Fast films
Larger crystals
Require less exposure
Produces a grainier image
Less latitude

18. X-ray Film Characteristics
Film speed
 Slow films
Smaller crystals
Require greater exposure
Higher definition image/less grainy
Greater latitude

19. X-ray Film Characteristics
Film speed
 Based upon size of
silver halide
crystals

20. X-ray Film Types
Two general types
 Non-screen film
 Screen film

21. X-ray Film Types
Non-screen film
 More sensitive to ionizing radiation
Allows for finer detail
Requires more exposure
Requires thicker emulsion and thus manual
processing
 Ex.: dental films

22. X-ray Film Types
Screen film
 Crystals also sensitive to fluorescent light
from intensifying screens
 Less sensitive to direct ionizing radiation
 Benefits
Less exposure
 Drawbacks
Loss of image definition

23. X-ray Film Types
Screen film
 Blue sensitive film
Film responds to ultra-violet, violet and blue light
emitted from screen
 Green sensitive film
Respond to screens that emit 60% green and 25%
blues
Relatively newer technology using rare earth
phosphors

24. X-ray Film Types
 Blue and green screen can be used with
either blue or green sensitive film
But most efficient if film is sensitive to light
emitted by screen

25. X-ray Film Types
Screen film
 Standard silver halide crystals absorb violet to
blue light
 “Ortho” film
Thin layer of green absorbing dye transfers energy
to silver halide crystals
Therefore extends sensitivity of film into green
wavelengths
 “Pan” film
Red absorbing dye

26. X-ray Film Types
Screen film
 Crossover or punch-
through effect
Decreased detail of
radiograph due to
additional exposure to
light from screen on
opposite side

27. X-ray Film
Common sizes
 14 x14
 14 x17
 7 x17
 8 x 10
 10 x 12
 11 x 14

28. Intensifying screens
Thin cleanable sheet of phosphor crystals
which lies adjacent to the film within the
cassette
Purpose:
 To decrease amount of radiation required for
a diagnostic radiograph
Able to use lower mAs (faster exposure)

29. Intensifying screens
4 layers of a screen
 Base
Substrate for phosphor crystals
 Reflecting layer
To reflect light back toward film
 Phosphor layer
Must be uniform and flexible (to avoid cracking)
 Protective coating

30. Intensifying screens

31. Intensifying screens
 Intensification factor
Direct film requires roughly 34 times more
exposure than screen film
A 0.1 second exposure on screen film
would require 3.4 seconds on non-screen
film

32. Intensifying screens
 Screen speed
Larger crystal = faster screen = more grainy
Thicker phosphor layer = faster screen =
decreased detail

33. Intensifying screens
 Phosphor layer
Calcium tungstate and barium lead sulfate
emit blue light
Rare earth screens more green light
emitted
 Extremely important to keep screens
clean and undamaged

34. Film holders
Cassettes
 Must be rigid, durable, light-proof and
transparent to x-rays on at least one face
 Provide housing for intensifying screens and
film
 Must be maintained well

35. Cassettes

36. Film holders
Cardboard or light-proof paper
 Use for non screen films
 Light-weight
 Low/no maintenance

37. Manual Film Processing
Dark room
 Must be light-proof
Tight seal of door
Stray light may fog film
 Must be not be exposed to radiation
Adjacent x-ray machine may cause fogging of film

38. Manual Film Processing
 Dry area
Film storage
 Use lightproof cabinet
Cassette loading
Safelight
 Must be of visible spectrum that will not fog film
 Red part of spectrum

39. Manual Film Processing
 Wet area
Solution tanks
Sink
Viewer
Hangers

40. Manual Film Processing

41. Manual Film Processing
Developing
 Developer solution reduces silver bromide
crystals to black metallic silver

42. Manual Film Processing
Developing
 Chemical process dependant upon time and
temperature
Ideally 5 minutes in developer tank at 68 degrees
Fahrenheit
High temperature causes reticulation
 Artifact caused by slipping of emulsion layer

43. Manual Film Processing
Rinse bath
 Water
 About 30 seconds

44. Manual Film Processing
Fixer
 Converts undeveloped silver bromide crystals
into a solution that is washed away
Black metallic silver left on film
 Also hardens film

45. Manual Film Processing
Minimum fixing time
 Determined by change in film appearance
from cloudy to clear (clearing time)

46. Manual Film Processing
After clearing, film should be left in for
twice that amount of time
 Ex. 2 minutes to clear = keep film in 4
additional minutes
Clearing time should not exceed 2-3 minutes

47. Manual Film Processing
Washing
 Removes residual silver and fixer
 20 minutes if water changes 10 times per hour

48. Manual Film Processing
Drying
 Perform in clean cabinet
Avoid dust artifacts, water spots

49. Automatic Film Processing
Benefits
 Compact size
 Faster
 More consistent
 Time and temperature controlled
 Produces dry radiograph immediately

50. Film Processing
Solutions need to be specially disposed
due to contents
 Treated as hazardous waste in many
including California