major components of x-ray generating unit · grid reduces scatter radiation from certain...

HDR104

SCHOOL OF MEDICAL IMAGINGFACULTY OF HEALTH SCIENCES

PREPARED BY:MR KAMARUL AMIN BIN ABDULLAH

CHAPTER 1

RADIOGRAPHIC EQUIPMENT AND IMAGE RECORDING 1

MAJOR COMPONENTS OF X-RAY GENERATING UNIT

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Chapter 1: Major Components of X-ray Generating Unit

TOPIC

LEARNING OUTCOMES

At the end of the lesson, the student should be able to:-

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.

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TOPIC OUTLINES

INTRODUCTION

1.1 X-ray Tube

1.2 Control Panel

1.3 X-ray Couch (Table)

1.4 Tube Stand

1.5 Bucky Tray

1.6 References

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INTRODUCTION

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1.1 X-ray Tube

1.1.1 Specifications

It is attached to a tube support.

It produces X-rays & Heat.

It can operate at high voltage which

ranges from 40 - 150 kVp.

It has an insulation which is lead

lined to avoid leakage of radiation.

Oil is used to cool X-ray tube during

exposures.

It has an indicator such as height,

kVp, mAs and motion.

Figure 1: The x-ray tube.

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1.1 X-ray Tube

1.1.1 Specifications (Continued)

It is being incorporated with safety

interlocks to avoid injury to staff

and patients.

It has Light Beam Diaphragm to

include the area of interest.

It also has an Integrated

Collimation with various sizes

according to the projection and

cassettes/films.

This equipment is Earthed

(Shockproof).

It is connected with high tension

cables that supplies the high voltage

current.Figure 1: The x-ray tube.

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1.1 X-ray Tube

Figure 2: The x-ray tube with diagram.

X-ray tube encased within

LEAD lined case.

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1.2 Control Panel

There are THREE primary control

1. kVp – quality

2. mA

3. Time

Auxiliary control (anatomical programs @ AEC control)

quantity

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1.2 Control Panel

Figure 3: The picture shows an example of control panel.

mA

selector

Exposure

Switch

Anatomical

Part

Selector

Main

Power

AEC

Bucky

Selector

Focal Spot

Selector

kVp

Selector

Timer

Selector

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1.2 Control Panel

Figure 4: Control Panel

(Somasundaram, 2009)

Figure 5: Control Panel

(Medilux, 2010)

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1.2 Control Panel

1.2.1 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.

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1.2 Control Panel

1.2.2 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.

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1.2 Control Panel

1.2.3 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.

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1.2 Control Panel

1.2.4 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 6: Automatic Exposure

Chamber – Ionization Chamber.

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1.2 Control Panel

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.

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1.2 Control Panel

Figure 7: The position of the chambers.

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Figure 8: The picture shows the x-ray

table/couch.

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1.3.1 Specifications

It must be strong enough to support

large patients or obese.

It should have low attenuation

materials (such as Carbon Fibre) as

to improve quality of x-ray beam.

It has Rise and Fall facilities.

Figure 9: X-ray Couch

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1.3.1 Specifications (Continued)

It has “Kick” buttons.

Incorporated with an Integrated

“Bucky” tray.

Insulated to avoid electrical shocked.

It is easy to clean as to reduce cross

infection .

It is associated with pressure switches.

Figure 9: X-ray Couch

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1.4 Tube Stand

Figure 10: Ceiling Mounted X-ray

Tube

Figure 11: Floor Mounted X-ray

Tube

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1.4 Tube Stand

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

Figure 10: Ceiling Mounted X-

ray Tube

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1.4 Tube Stand

Advantages

Inexpensive.

Can be used with upright Bucky.

Require less space.

Disadvantages

Less flexible.

Not user friendly for complicated

cases.

Figure 11: Floor Mounted X-ray

Tube

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1.5 Bucky Tray

Figure 12: Table Bucky Figure 13: Erect Bucky

It actually acts as cassette holder.

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1.5 Bucky Tray

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

Figure 14: Bucky Tray with Grid.

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1.5 Bucky Tray

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

film

Figure 15: The x-ray tube and bucky.

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1.5 References

No. REFERENCES

1 Richard R. Carlton, Arlene McKenna Adler (2005) Principles of

Radiographic Imaging, Delmar

2 Bushong, S. C. (2008). Radiologic science for technologists. Canada:

Elsevier.

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SUMMARY

There are FIVE major components of x-ray generating unit:-

1. X-ray Tube

2. Control Panel

3. X-ray Couch

4. Tube Stand

5. Bucky Tray

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NEXT SESSION PREVIEW

CHAPTER 2: ELECTROSTATIC

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APPENDIX

FIGURE SOURCE

Figure 1 http://www.actors.co.ke/en/news/Energy1.jpg

Figure 2 http://intechweb.files.wordpress.com/2012/03/shutterstock_77399518.jpg

Figure 3 http://www.solarenergybook.org/wp-content/uploads/2009/12/solar-energy-

example.gif

Figure 4 http://www.petervaldivia.com/technology/energy/image/potencial-and-

kinetic.bmp

Figure 5 http://iws.collin.edu/biopage/faculty/mcculloch/1406/outlines/chapter%206/S

B7-2b.JPG

Figure 6 http://www.petervaldivia.com/technology/energy/image/potencial-and-

kinetic.bmp

Figure 7 http://www.physics4kids.com/files/art/motion_energy1_240x180.jpg

Figure 8 http://www.sciencebuilder.com/michigan/science/images/p/potentialenergy.j

pg

Figure 9 http://4.bp.blogspot.com/_V7DuEO3c2E8/S-

b2PZfOXZI/AAAAAAAAADk/KKXoueyon2I/s1600/One-balanced-rock.jpg

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APPENDIX

FIGURE SOURCE

Figure 10 http://im.glogster.com/media/2/6/1/15/6011523.jpg

Figure 11 http://cse.ssl.berkeley.edu/bmendez/ay10/2002/notes/pics/bt2lf0403_a.jpg

Figure 12 http://www.petervaldivia.com/technology/electricity/image/electron-flow.gif

Figure 13 http://newsimg.bbc.co.uk/media/images/42340000/gif/_42340232_nuclear_fus

ion_2inf416.gif

Figure 14 http://freegrab.net/114284main_EM_Spectrum500.jpg

Figure 15 http://myweb.cwpost.liu.edu/vdivener/notes/solid-liquid-gas.gif

Figure 16 http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/inteng.html

Figure 17 http://hop.concord.org/h1/h1pix/P2b.GIF

Figure 18 http://www.aos.wisc.edu/~aalopez/aos101/wk5/conduction.jpg

Figure 19 http://www.gcse.com/energy/images/conduction.gif

Figure 20 http://okfirst.mesonet.org/images/cond_conv_rad_small.jpg

Figure 21 http://www.aos.wisc.edu/~aalopez/aos101/wk5/convection.jpg

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APPENDIX

FIGURE SOURCE


Figure 23 http://www.aos.wisc.edu/~aalopez/aos101/wk5/radiation.jpg


Figure 25 http://www.aos.wisc.edu/~aalopez/aos101/wk5/heatrans.jpg

Figure 26 http://www.beodom.com/assets/images/education/principles-thermal-

insulation/heat-transmittance-means.jpg

Figure 27 http://www.drenergysaver.com/images/insulation/how-insulation-works.gif

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TOPIC

Answer the question.

Test Your Knowledge

Activity

What is the push or pull of an object that can cause it to accelerate called?

Mass

Speed

Force

major components of x-ray generating unit · grid reduces scatter radiation from certain...

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