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MAJOR COMPONENTS OF X-RAY
GENERATING UNITS
Prepared by:-
EN KAMARUL AMIN BIN ABDULLAH
XRAY HISTORY
Wilhelm Conrad Röntgen - First X-ray
On 8 Nov, 1895, Wilhelm Conrad Röntgen (accidentally) discoveredan image cast from his cathode ray generator, projected far beyondthe possible range of the cathode rays (now known as an electronbeam). Further investigation showed that the rays were generated atthe point of contact of the cathode ray beam on the interior of thevacuum tube, that they were not deflected by magnetic fields, andthey penetrated many kinds of matter.
A week after his discovery, Rontgen took an X-ray photograph ofhis wife's hand which clearly revealed her wedding ring and herbones. The photograph electrified the general public and arousedgreat scientific interest in the new form of radiation. Röntgen namedthe new form of radiation X-radiation (X standing for "Unknown").Hence the term X-rays (also referred as Röntgen rays, though thisterm is unusual outside of Germany).
CONTENTS
1.0 X-RAY TUBE
2.0 CONTROL PANEL (OPERATION CONSOLE)
3.0 X-RAY COUCH
4.0 TUBE STAND
5.0 BUCKY
OBJECTIVES
Describe what x-ray tube is.
Identify the parameter selectors on control panel and
their functions.
Discuss the characteristics of x-ray couch.
Describe the types of tube stand.
Describe briefly the principle of Bucky.
METHODOLOGY OF PRODUCING A
RADIOGRAPH
Patient positioned in relation to exam being undertaken.
Radiographic equipment (i.e. X-ray tube) positioned.
Exposure set on control panel.
Instructions given to patient.
Radiographer stands behind lead glass screen.
Exposure undertaken.
Cassette processed.
Radiograph reviewed.
Figure A: The X-ray Room
1.0 X-RAY TUBE
Attached to a tube support.
Produces X-rays (& Heat).
Operated at high voltage (40 - 150 kVp).
Insulation required.
Oil used to cool X-ray tube during exposures.
Oil also acts as an insulator.
X-ray tube lead lined.
Incorporate safety interlocks.
Light Beam Diaphragm.
Integrated Collimation.
Equipment Earthed (Shockproof).
Figure 1.1: The x-ray tube.
Figure 1.2: The x-ray tube with diagram.
X-ray tube encased
within LEAD lined
case.
2.0 CONTROL PANEL (OPERATION
CONSOLE)
THREE primary control
a) kVp – quality
b) mA
c) Time
Auxiliary control (anatomical programs @ AEC control)
quantity
Figure 2.1: The picture shows the control panel used at UiTM
PJ.
mA
selector
Exposure
Switch
Anatomical
Part
Selector
Main
Power
AEC
Bucky
Selector
Focal Spot
Selector
kVp
Selector
Timer
Selector
Figure 2.2: Control Panel
(Somasundaram, 2009)
Figure 2.3: Control Panel
(Medilux, 2010)
2.1 kV, mA and Timer(s) selectors
kVp(KiloVoltagePeak)
The energy (the penetrating power) of the x-ray beam is
controlled by the voltage adjustment.
It is labelled in keV (thousand electron volts) and
sometimes the level is referred to as kVp (kilovoltage
potential).
The higher the voltage setting, the more energetic will be
the beam of x-ray.
It plays major part in affecting contrast of image.
mA (MiliAmperage)
The second control of the output of the x-ray tube is
called the mA (milliamperage) control.
This control determines how much current is allowed to
flow through the filament which is the cathode side of the
tube.
The effect of the mA circuit is quite linear.
It is more concerned in density aspect of the image.
Timer (s)
Control length of time machine produces x rays
This is usually denoted as an "S" (exposure time in
seconds) and is combined with the mA control.
e.g using 10 milliampere seconds you could use a 10 mA
current with a 1.0 second exposure or a 20 mA current
for a 0.5 second exposure or any combination of the two
which would result in the number 10.
Both of these factors and their combination affect the
film in a linear way.
2.2 AEC (Automatic Exposure Chamber)
Variable densities exist within
subjects.
AEC’s monitor the beam
of X-rays transmitted from the
patient.
Production of X-ray radiation can
be measured.
Located under patient but above
cassette.
Minimizes inaccurate exposures.
Figure 2.4: Automatic Exposure
Chamber – Ionization Chamber.
Exposure terminates once a sufficient quantity of radiation has been received to produce a radiographic image of required density.
Permit accurate exposures
Usually three AED’s incorporated in table tops and vertical chest stands.
Markings usually on surface of table/chest stand.
Individual chambers may be selected – depending on the exam being performed.
Figure 2.5: The position of the chambers.
3.0 X-ray Couch
Figure 3.1: The picture shows the x-ray
table/couch available at UiTM PJ.
3.1 Characteristics of X-ray Couch
Strong enough to support large patients.
Low attenuation materials (Carbon Fibre).
Rise and fall facilities.
“Kick” buttons.
Integrated “Bucky” tray
Insulated.
Easy to clean – Cross infection
Pressure switches.
Figure 3.2: X-ray Couch
4.0 TUBE STAND
Figure 4.1: Ceiling Mounted X-ray
Tube
Figure 4.2: Floor Mounted X-
ray Tube
4.1 Ceiling Mounted
Advantages
Flexibility
Ease of use and Durable
Safety features/interlocks
Specifications of modern X-ray tube
Integral features
Wide range of movements
Disadvantages
Expensive
Interlock – too sensitive
4.2 Floor Mounted
Advantages
Inexpensive.
Can be used with
upright Bucky.
Require less space.
Disadvantages
Less flexible.
Not user friendly
for complicated
cases.
5.0 BUCKY
Figure 5.1: Table Bucky Figure 5.2: Erect Bucky
• It actually acts as cassette holder.
Characteristics of Bucky
Integrated within table top.
Lock mechanism ensures cassette is secure.
Grid mechanism incorporated within cassette tray.
Grid reduces scatter radiation from certain examinations
– Abdomen
– Pelvis
– Hips
Important that X-ray
tube and cassette tray
are aligned
Set distance between X-
ray tube and Cassette
tray
Oscillating movement
ensures scatter is
absorbed before reaching
filmFigure 5.3: The x-ray tube and bucky.
Continue to Next Lesson…..
Accessory Equipment….
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