1. UNIT 5A Introduction to Radiographic Equipment
General Radiographic, Fluoroscopic
Dedicated, Multipurpose & Mobile
Conventional vs. Digital

2. General Radiographic Equipment
Multi-purpose / general radiographic equipment - a wide range of procedures can be performed using this type of equipment
It is used for general and/or routine radiography.
Examples: orthopedic radiography, chest, podiatric, abdomen, spine and skull radiography

3. General Radiographic Equipment
Multi-purpose general radiographic equipment
Stationary
Conventional (cassette-based film)
Digital (CR – cassette-based)

4. DR (Direct Digital) Radiographic Equipment
Multipurpose
stationary
IR integrated into the equipment (cassetteless)

5. Terminology Conventional - Uses film in cassettes (film holders)
Digital - Filmless; image is viewed on monitor
CR – computed radiography – uses conventional equipment with cassettes
DR – Direct digital radiography – uses special equipment; cassetteless

6. Image Receptors
Defined as the device that receives the energy of the x-ray beam and forms the image of the body part
Four types
Cassette with film (conventional)
Image plate (IP – used in CR)
Direct radiography (detector)
Fluoroscopic screen

7. The X-ray Tube X-rays are produced in a cathode ray tube
They are produced from a series of energy conversions

8. Requirements for the production of x-rays include:
A source of electrons (the filament or cathode)
A means to accelerate the electrons (kVp)
A way to stop the electrons (the target or anode)

9. The x-ray tube Is an evacuated glass envelope
Has a positive (anode) and negative (cathode) electrode.
The cathode (filament) serves as the source of electrons
High voltage is applied (kVp) to accelerate the electrons across the tube
The anode (target) stops the electrons suddenly which results in the production of x-rays

10. X-ray production The energy conversion involves the conversion of
electrical energy to..
heat energy to..
kinetic energy to..
x-ray energy and heat energy.
>99% of the energy conversion results in heat
<1% of the energy conversion results in x-rays

11. The x-ray tube
Tube housing protects the patient and operator from radiation emanating in all directions.
The collimator decreases or increases the size of the x-ray field (inc or dec pt. & operator exposure.)
PBL-positive beam limitation-automatic collimation – detects size of image receptor and automatically reduces/increases beam size to correspond.

12. Tube Stand
The device that supports and permits the x-ray tube to be moved in different directions.
Floor-mounted – runs along a track on the floor.
Floor-to-ceiling or Floor-to-wall - has add’l tracks on wall or ceiling
Ceiling-mounted – provides most flexibility

13. X-ray tube controls
Longitudinal lock - locks tube into position along the length of the table
Transverse lock-locks tube into position across the width of the table
Vertical lock-locks tube vertically to set the SID*
Collimator controls
*SID is the distance between the source (anode) and the image receptor (IR)

14. Detent lock-locks the tube into the center of the bucky tray (where IR is) transversely.
Tube angulation lock-allows angulation of the tube cephalad (towards the head) and caudad (towards the feet)
Tube angle indicator-indicates the degrees of tube angulation
X-ray tube controls

15. The table is designed to support the patient in a position that enhances the radiographic examination
It is not designed for comfort!
Radiographic Tables

16. The table must be uniformly radiolucent (allows x-rays to easily pass through)
It must be easily cleaned.
It must be hard to scratch.
Some tables are stationary (ie. They don’t move)
Radiographic Tables

17. Radiographic Tables
Tables must have a space for a tray (Bucky tray) to hold image receptors (IR) and a radiographic grid IR
Bucky Tray

18. Image Receptors Image receptors (IR) can either be film cassettes or
CR (computerized radiography) imaging plates (IP).

19. IR Orientation

20. Radiographic Table Accessories
Grid –is installed over the tray & consists of Pb strips and is used to absorb scattered radiation which causes fog that degrades the visibility of image detail.
Some grids consist of a mechanism that automatically moves the grid during exposure (reciprocating grid).
Others use a stationary grid (one that does not move).

21. Radiographic Tables Tables can be “fixed” or “tilting”
Fixed (stationary) tables do not permit tilting of patient’s head or feet
Tilting tables are used mostly for radiographic/fluoroscopic applications
Table height is typically 30-40” from the floor.
Some fixed tables have adjustable heights to assist patients on and off the table

22. Radiographic Tables Tabletops are usually movable
Some are motor-driven along their length
Some are “floating tops” which move along length and width simultaneously
Brakes can be controlled by hand, knee or foot.
Movable tables are an advantage in moving/positioning large patients!

23. Radiographic Table Accessories
Footboards are an accessory used to support the patient in a standing position when tilting tables are employed.
should be exercised to assure the footboard is attached correctly to prevent injury to the patient!

24. Wall-Mounted Bucky System and Cassette Holders
Allows standing radiographs
Cassette holder – adjustable; holds various size cassettes.
Wall-Mounted Bucky – Cassette holder (tray) with grid.
DR (Digital Radiography) does not use a bucky tray; image receptor does not have to be changed between exposures

25. Generator or Control panel
KvP Selector
mA Selector
Exposure time Selector
Table bucky vs upright Bucky switch
On/Off switch
Exposure switch
Generator or Control panel

26. kVp Selector
Selects the kilovoltage applied to the x-ray tube to produce x-rays
Diagnostic Range 45kVp-150kVp
Major/Minor (increments of 10 kV/1kV)
KvP controls the penetrating power of the x-ray beam (and therefore the # of x-rays reaching the film)
KvP controls the energy of the beam
KvP affects density (darkness/brightness) and contrast of the image (more on this in a later lesson)

27. mA selector Selects the milliamperage (mA;x-ray tube current)
Heats the filament; boils off electrons (thermionic emission)
Controls the # of electrons flowing from cathode to anode (ie. Tube current)
Controls the amount of x-rays produced
Controls the amount of exposure delivered to the patient.
Controls the density (darkness) or brightness of the image
Range 25mA-1200mA (varies with equipment)

28. Exposure time selector
Selects the length of the exposure
Range from milliseconds to 6 seconds (varies with equipment)
Controls the time electrons flow from cathode to anode
Controls the amount of exposure
Controls the density or brightness of the image

29. mAs mAs is the product of mA X exposure time
It represents the quantity of radiation exposure delivered.
Ex: /20 second = 5 mAs
Ex: second = 5 mAs

30. Table bucky vs upright Bucky switch
Available when room has a table bucky and an upright bucky
Activates the reciprocating bucky in table or upright.

31. Other controls On/Off switch - turns power to controls on or off
Exposure switch - remote control switch which controls exposure
prep stage - heats cathode and rotates anode*
exposure stage - makes exposure(applies kV)
*Holding the “prep” or “rotor” down for an extended time decreases the life of the x-ray tube!

32. Other controls
AEC - Automatic Exposure Control - Automatically terminates exposure when predetermined amount of exposure is reached.
Determines the amount of exposure needed to produce a diagnostic image.
Actually controls the exposure time.
Operator selects kVp (and sometimes the mA) and appropriate cells (detectors)

33. AEC (Automatic Exposure Control)
Provides automatic control of x-ray exposure
exposure automatically terminates when the film has received desired amount of film
AEC

34. Radiographic/Fluoroscopic Equipment
Radiographic equipment produces static images only.
Fluoroscopic equipment produces static AND dynamic images.

35. Radiographic/Fluoroscopic Equipment
In addition to the components already discussed, fluoroscopic equipment has a movable fluoroscopic carriage which includes:
Image intensifier
An additional x-ray tube under the table

36. Radiographic/Fluoroscopic Equipment
Spot film device – permits the radiologist to obtain static images during the fluoroscopic exam.
Uses various cassettes
Allows one or more exposures/image receptor.
Digital fluoroscopy allows digital acquisition of spot films (cassetteless)
Stores static images on a computer.

37. Mobile Radiographic and Fluoroscopic Equipment
Used for radiography:
At the patient’s bedside
In the surgical suite
In the emergency department
Mobile equipment has similar controls to stationary equipment but no table.

38. Mobile Radiographic and Fluoroscopic Equipment
A mobile fluoroscopic unit is sometimes called a “c-arm”

39. Introduction to the Darkroom
Cassettes
Radiographic Film
Storage and Handling
Essentials of the Darkroom
Automatic Processor

40. Cassettes Cassettes are a light-tight film holder.
They have a radiolucent (allows x-rays to pass through) front (tube side)
The back side usually has Pb (lead) or Al (aluminum) to absorb back scatter.
Cassettes come in a variety of standard sizes.
Cassettes

41. Standard Cassette Sizes
English
14” X 17”
14” X 14”
11” X 14”
10” X 12”
9.5” X 9.5”
8” X 10”
7” X 17”
Metric
35 X 43cm
35 X 35cm
28 X 35cm
24 X 30cm
24 X 24cm
20 X 25cm
18 X 43cm

42. Cassettes
Most cassettes have intensifying screens mounted on the front and back inside surface.
An Intensifying screen is a fluorescent material that converts x-ray energy to light energy which exposes the film.
The purpose of intensifying screens is to reduce patient exposure.
Some cassettes have a single intensifying screen; some have two intensifying screens.

43. Intensifying Screens
An intensifying screen is composed of fluorescent phosphors which give off light when struck by x-rays.
Different phosphors give off different colors (spectra) of light
In radiography, most emit blue, blue/violet or green light.
Radiography film is most sensitive to one of these spectrum.

44. Luminescence: Fluorescence vs. Phosphorescence
Luminescence - emission of light
Fluorescence - when a phosphor emits light upon being struck by x-rays, and light emission ceases when the x-ray source ceases.
Phosphorescence - (aka “screen lag”) when a phosphor emits light upon being struck by x-rays, but the light continues to glow after the x-ray source ceases.

45. Radiographic Film
Radiographic film is the primary medium of conventional radiography.
It is composed of a polyester base which is tinted blue,
And a coating of emulsion (the light & x-ray sensitive component of film) which is composed of AgBr crystals suspended in gelatin

46. Radiographic Film
Film can either have emulsion coated on one side (single emulsion)
or can be coated on both sides (duplitized).
Single emulsion film is used with cassettes with single screens.
Duplitized film is used with dual-screen cassettes.

47. Radiographic Film Classifications:
Speed - reflects the sensitivity (response) of the emulsion to x-ray and light exposure.
ex: 100, 200, 400, 800 speed; the higher the number, the more sensitive the emulsion (requires less exposure)
Contrast - how the film exhibits the relationships between blacks and whites.
Resolution (detail) - how the film reproduces details of the subject.

48. Film Storage and Handling
Ideal storage temperature - 68o
Ideal humidity %
Stored film must be protected from:
radiation
light
age
pressure
high temperatures
too high/low humidity

49. Artifacts-foreign marks on the film
Fog – gray/black appearance of film
Caused by: Exposure to radiation, light or age
Fog destroys visibility of details.
Static-black “lightening”-like artifacts
Caused by: Static discharge in the darkroom due to low humidity & electrification by friction.
Crescent (“crinkle”) marks- black moon-shaped artifact.
Caused by: Bent film (mishandling)

50. Darkroom Should be a safe environment for handling radiographic film.
Safelight-allows visibility in the darkroom without fogging the film!
Maximum intensity of bulb- 15 watts
Safelight filters
GBX - red light (for green or blue sensitive films
Wratten 6B amber light for blue sensitive only (not used today)
Safelight can be direct or indirect .

51. Darkroom - film storage
Film bins provide various sizes of film a light-tight & radiation proof storage .
Films are stored largest film to smallest film (front to back)
Boxes of film are stored on end to prevent pressure artifacts.
The FIFO method (First in; first out) of film usage prevents film from being used after it’s expiration date.
Expiration dates are stamped on each box

52. Darkroom – The Automatic Processor
There are four racks in an automatic processor: Developer Fixer, Wash, Dryer
Processing temperature is 90-95o F.
Most processors process films in 90 seconds.
Darkroom – The Automatic Processor

53. Automatic Processor Identify the following in the Darkroom:
Main switch ( on wall)
Power on/off (on processor)
Film tray
Water valve
Replenishment tanks
One for developer; one for fixer
hoses

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