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RADIOGRAPHIC EQUIPMENT
Adler & Carlton Ch. 8
&
Bushong Ch. 1
Modern radiology
Two basic types of x-ray examinations
• Radiography
• Fluoroscopy
2
Radiography exam
3
Radiographic Room
The transformation from a physicist toy to a valuable, large scale medical specialty
• 1907 Snook transformer – high voltage
• 1913 Coolidge x-ray tube – air evacuated, separate selection of voltage and current
• Standardizing x-ray tube beam output
6
THE X-RAY TUBE
• The X-Ray tube is the single most important component of the radiographic system. It is the part that produces the x-rays
THE X-RAY TUBE
• GLASS ENCASED IN STURDY STEEL HOUSING
• PRIMARY COMPONENTS
– ANODE +
– CATHODE --
XRAY TUBE HOUSING
• MADE OF LEAD AND STEEL
• TO ABSORB ANY STRAY RADIATION
• TO PREVENT LEAKAGE RADIATION FROM THE TUBE
TUBE HOUSINGMADE OF LEAD & STEEL
How “X-rays” are createdSEE: MAN MADE RADIATION (PG.111)
Adler & Carlton
TO PRODUCE X-RAYS
YOU NEED:
• A SOURCE OF ELECTONS
• A FORCE TO MOVE THEM QUICKLY
• SOMETHING TO STOP THEM SUDDENLY
How “X-rays” are created
• Power is sent to x-ray tube via cables
• mA (milliamperage) is sent to filament on cathode side.
• Filament heats up – electrons “boil off”
• Negative charge
How “X-rays” are created
• Positive voltage is applied to ANODE
• Negative electons = attracted across the tube to the positive ANODE.
• Electrons “slam into” anode – suddenly stopped.
• X-RAY PHOTONS ARE CREATED
How “X-rays” are created
• Electron beam is focused from the cathode to the anode target by the focusing cup
• Electrons interact with the electrons on the tungsten atoms of target material
• PHOTONS sent through the window PORT – towards the patient
More on the tube later……..
X-RAY TABLE
Radiographic tables Are designed to support the patient
during a radiographic exam Comfort is not the primary concern Foam pads should be used if the patient
will be required to be on the table for longer than 10 minutes
Tabletop
Must be uniformly radiolucent to easily permit x-ray to pass through.
Carbon fiber is used because it is strong and very little x-ray photons are absorbed.
Usually tabletops are flat however some are curved
Tabletop
Most tabletops are floating, some are motor-driven
The brakes can be released usually by the technologist hand or foot
The brakes are electromagnetic Floating table tops save significant
amounts of time and strain on the technologist
Tables
Tables are fixed or tilting Fixed rooms are designed for diagnostic
radiographic work only
• The table can usually be raised or lowered to accommodate the patient and
the technologist.
Table top technique
Performing imaging using just the cassette, plate or digital image receptor
Also called “non- grid” technique
Fluoroscopy exam
26
FLUOROSCOPYIMAGES IN MOTION
Fluoroscope1898 by Thomas Edison
28
Radiation Injury
29
1904 the first recorded x-ray fatality in the US – Clarence Dally, Edison’s assistant
Early injuries took the form of skin damage, loss of hair and anemia
Snook transformer & Coolidge tube reduced the injuries Why?
Tables
Tilting rooms are designed for both diagnostic and fluoroscopic work• Tilting models usually tilt to 90 degrees in
one direction and 15 – 30 degrees in the other direction
• Tilting models include ancillary equipment; footboard, shoulder support, handgrips, compression bands
Table Movement
Longitudinal Transverse Vertical Tilt or Angling
Fluoroscopy tables: the tube is under the table, image capture is above the patient
Tube Supports
Designed to help technologists with various tube locations for creative imaging.
Tube suspension systems are available in 5 versions:• ceiling mounted, floor-to-ceiling, floor, mobile
and c-arm.
Tube Movement
• Longitudinal
• Transverse
• Vertical
• Angling or Rolling
• Rotating
• Telescoping
Improvement in radiography
Reducing exposure time to reduce blur
Dentist William Rollins began using a diaphragm to improve image quality• First application of collimation and filtration
1921 Potter-Bucky grid – improving image contrast
42
Dr. William Rollins • Dr. William Rollins was a
Boston physician and dentist who was the first to use collimation and filtration in the late 1800s.
• After receiving radiation burns to his hand in x-ray experiments in 1898, he used leather and aluminum filters when he made x-ray exposures of his patients' teeth.
43
The ‘BUCKY’
• The Potter-Bucky is the device in the table or chest board that holds the film cassette. The ‘bucky’ is like a drawer that opens and closes to insert and remove the film cassette.
TABLE OR UPRIGHT BUCKY TRAY
Radiographic grid ?
Bucky cross hatched
• Grids are used to “clean up” scatter radiation from the patient
• To improve • contrast on the
radiograph• Potter-Bucky are
usually a focused moving grid
CASSETTES W/ GRID CAPS
Radiation shields
Viewing images
• View boxes
• Computer monitors
COLLIMATOR
• ATTACHES DIRECTLY BELOW THE X-RAY TUBE
• SERVES AS A X-RAY BEAM LIMITING DEVISE
• CONTROLS THE SIZE AND SHAPE OF X-RAY FIELD
Cone collimator
• ALWAYS KEEP THE COLLIMATED AREA SMALLER THAN THE SIZE OF THE CASSETTE
X-ray tubecontrols
• Displays– Tube angle– Distance to table top
bucky– Collimator controls– Tube lock controls– High voltage cables
CASSETTE or FILM HOLDER
• The CASSETTE is used to hold the film during examinations. It consist of front and back intensifying screens, and has a lead (Pb) backing. The cassette is light tight
• CR image capture
• PSP Plate
• PHOTOSTIMULABLE PHOSPHOR PLATE
FILM FILM direct exposure & screen-film or film-screendirect exposure & screen-film or film-screen
SIZESSIZES
14 X 1714 X 17
14 X 1414 X 14
11 X 1411 X 14
10 X 1210 X 12
8 X 108 X 10
Film SizesFilm Sizes
Standard “inches”:Standard “inches”:
8” x 10”8” x 10”
10” x 12”10” x 12”
11” x 14”11” x 14”
14” x 17”14” x 17”
Metric:Metric:
18cm x 24cm18cm x 24cm
24cm x 30cm24cm x 30cm
30cm x 35cm30cm x 35cm
35cm x 43cm35cm x 43cm
• DR(DDR)
• Collection element • TFT (Thin film
transistor)• Photodiode• CCD (charge-coupled
device)
CONTROL CONSOLE
• GIVES THE TECHNOLOGIST CONTROL OF THE X-RAY MACHINE
• TECHNIQUE SELECTION
• Located OUTSIDE of the Radiographic Room
The Control Console
• The control console is device that allows the technologist to set technical factors (mAs & kVp) and to make an exposure.
• Only a legally licensed individual is authorized to energize the console.
“Technique”kVp , mAs (mA x s)
• What is set at the control panel
• How the “image” is created on the “film” or Image receptor (digital)
• kVp controls the “ENERGY” of the beam
• The Higher kVp – more penetrating
• Ranges is 50 -110 in Diagnostic x-ray
+ 30% + 50 % mas
kVp Changes
Darkroom
What is in the Darkroom?
Safe Light
• 15 Watts
• Red filter
• Must be 3-6 feet from counter top or feed tray of processor
• Used to be amber or orange filter
UNLOAD EXPOSED FILM
FILM ID PRINTER
FILM BIN - STORAGE
Transport System (Rollers)
Turnaround
Entrance
Deep Racks
Crossover
Squeegee
Dryer
Feed Tray
Analog processor
CR processor
• What does a DDR processor look like?
Other x-ray stuff….
• Positioning phantoms • Pixie
Dosimeter
An instrument that detects and measures exposures to ionizing radiation
Personal vs Field survey instruments
Densitometer
Measures optical density on a radiograph
Step wedge or penetrometer
Test tool made from aluminum Accurately-calibrated filter strip that
provides a stepped range of exposures
Other x-ray stuff….
• Positioning sponges
• Lead markers
• Gurney