Transcript radiographic equipment

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 xrays
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 HOUSING
MADE OF LEAD & STEEL
How “X-rays” are created
SEE:
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 “nongrid” technique
Fluoroscopy exam
26
FLUOROSCOPY
IMAGES IN MOTION
Fluoroscope
 1898 by Thomas Edison
28
Radiation Injury
 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?
29
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



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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 XRAY 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 tube
controls
• 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
direct exposure & screen-film or film-screen
SIZES
14 X 17
14 X 14
11 X 14
10 X 12
8 X 10
Film Sizes
Standard “inches”:
8” x 10”
10” x 12”
11” x 14”
14” x 17”
Metric:
18cm x 24cm
24cm x 30cm
30cm x 35cm
35cm 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)
Entrance
Feed Tray
Deep
Racks
Turnaround
Crossover
Squeegee
Dryer
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