VET-120Diagnostic Imaging

Course Set-up5 Lessons (Webinars)5 Lesson ExamsFinal Proctored ExamRequired Reading

Diagnostic Imaging Study Guide Radiography in Veterinary Technology

(Lavin – 4th edition)

Studying for ExamsMake copy of Lesson PowerPointsTake excellent notes during WebinarsRead & highlight Assigned Readings

in Study Guide & Lavin bookPerform Self Checks in Study GuideLearn the Glossary at the beginning of

each Chapter in Lavin bookStudy Key Points & Review

Questions at end of each Chapter in Lavin book

Lesson 1 – X-ray Production and

Safety

Reading Prefaces to Lavin Textbook

Why?????

Online Resources

Animal Insides

Veterinary E-News Magazine

Animal Insideshttp://www.animalinsides.com/

Pulldown Menu

General Imaging Topics

Digital Practice Topics

Latest Imaging News

Books You

Need

Veterinary E-News Magazinehttp://www.vetxray.com/dyncat.cfm?catid=1393

Latest Issue

2 Major Goals in Course

Learn how to take quality “Diagnostic X-rays” with minimum retakes

Learn Radiation SafetyStaffAnimal

Glossary Terms – Page 4

X-ray Production

What Are X-rays?Definition

X-rays are a form of electromagnetic radiation similar to visible light, but with a much shorter wavelength

The Spectrum of Electromagnetic Waves

Physical Properties of X-raysWavelengthTravel

Straight lines Speed of light

FluorescenceCaptured on filmBiologic changes in living tissue

Glossary Terms – Page 10

Taking X-rays

Exposure Factors

Control PanelX-ray Machine

Exposure FactorsMilliamperage (mA)Peak Kilovoltage (kVp)Exposure Time (S)Focal-Film Distance (FFD)

Source-Image Distance (SID)

Control Panel – 3 Exposure Factors

On/Off Switch Milliamperage (mA) Exposure time (fractions of a second) kVp (peak kilovoltage)

Adjust this last

Exposure button/switch 2 stage button?

4th Exposure Factor – Focal-Film Distance (on machine, not control panel)

Anatomy of the

X-ray Machine

Parts of an X-ray Machine

X-ray Tube

Electrical Components

Collimator

Control Panel

The X-ray Tube (Ray Gun)Most expensive part of the machine

A “Ray Gun”An X-ray machine is

essentially a camera. Instead of visible light, however, it uses X-rays to expose the film.

The 5 Elements Needed to Make an X-ray Tube (Ray Gun)

Figure 2-1, Page 11

Source of electrons – cathode

Electron acceleration – transformers

Electron path open – vacuum

Electron target – anode

Outside envelope – glass envelope

The X-ray TubeFigures 2-1, 2-2 on pages 11-12

5 elements needed for x-ray production

Flow of electrons from cathode to anodeFigure 2-2, Page 12

Figure 2-7 Page 14

Example of a rotating anode.

Heel effect – The intensity of the primary x-ray beam is not uniform throughout all areas of the beam; the

intensity is greater toward the cathode side of the x-ray beam because of the angle of the anode target

area.

Figure 2-8Page 14

Demonstration of the heel effect.

Review of X-ray Tube Anatomy

Anatomy of an x-ray tube. A, Cathode. B, Anode. C, Tungsten filament. D, Focusing cup. E, Accelerating electrons. F, Tungsten target. G, Glass envelope. H, Aluminum filter. I, Generated x-rays. J, Beryllium window.

Summary:The Whole X-ray Story

The Patient

Making X-rays

Black & White on FilmsBlack – x-rays NOT absorbed by

animal’s body….. End up hitting filmWhite – x-rays absorbed by animal’s

body…. Fewer get to film

CollimatorMade of leadRestricts (collimates) SIZE of primary

x-ray beamLimits patient & staff exposure to beam Increases quality of x-ray beam

Less secondary (scatter) radiationDoes NOT intensify primary x-ray beamPermanent & adjustable types

Figure 2-18, Page 20 Collimator with lead shutters.

Collimator – ↓ Scatter Radiation

How Much to Collimate? Ideally, every film should have a

collimated edge around the entire filmUse of a smaller cassette is another

means of collimating

X-ray Positioning – X Marks the Spot!

Radiation Safety

Glossary Terms – Page 24

Ionizing RadiationDefinition

The use of electrons (an ionic subatomic particle) to produce x-rays

X-rays – an electromagnetic radiation that is a wave

Fundamental – Radiation should be respected, not feared!

Hazards of Ionizing RadiationRapidly dividing cells are at the greatest

risk of damage Nuclear membrane dissolves during

mitosis and meiosisSomatic damage

Yourself Genetic damage

Your future children/grandchildren

Exposure to Ionizing RadiationPatient exposure

Most animals will not have multiple x-rays in their lifetime……… exposure minimal

Personnel exposure All personnel taking x-rays are at risk Film Badges – Figure 3-2, Page 27 Dosimetry Services – Table 3-2, Page 27

Figure 3-2, Page 27Example of a radiation detection device called a film badge, which consists of a plastic holder containing radiation-sensitive film.

Monitoring DevicesFigure 3-2, Page 27

1-Badge System

Practical Application of Radiation Safety

Primary Beam Exposure

Secondary (Scatter) Radiation Exposure

Radiation “leakage” From Tube Housing

Primary Beam RadiationActual beam of x-rays from tubeMost intense radiationFundamental!!! No human body parts

should EVER be in an x-ray film, even if covered by lead!!!

Fundamental!!! Use of collimator on all films Limits size of the primary beam

Primary RadiationTherefore…Cover your rapidly dividing cells with

lead and stay out of the primary beam – or else!

Secondary RadiationFigure 3-4, Page 28

AKA “scatter radiation”Occurs when primary beam interacts

with objects in its path Patient Tabletop Floor

Figure 3-4, Page 29 – Example of scatter radiation due to interaction of the primary x-ray beam with the table-top.

Figure 3-8, Page 30 A, Appropriate posture for manual restraint during exposure. B, Improper posture for manual restraint during exposure.

Secondary RadiationThis is THE MAJOR SOURCE of

radiation exposure for RVT’s2 major factors

kVp level (higher = more scatter)Thickness of patient

Therefore…AVOID RETAKES!!!

PPPPP

Radiation Safety FundamentalOne of the best ways to minimize

radiation exposure in the workplace is to avoid the occurrence of retakes. It should be the radiographer's goal to achieve a quality radiograph on the first attempt. This not only reduces radiation exposure to the patient and restrainers, but it is also cost effective and saves time.

Radiation Safety ChecklistPage 31

Minimal personnelLess than 18 years old or pregnantRotate personnelUse of mechanical restraints

Gauze, tape, foam positioning devicesUse of chemical restraintProtective apparelNEVER any body parts in primary beam

Figure 3-9, Page 30 A poor radiation safety practice. Hands should

never be positioned within the field of the primary x-ray beam, even with lead gloves on.

What’s Wrong in This X-ray?

Mechanical Restraints

Easy to position animals for a variety of procedures. Made from medical-grade, non-sterile aesthetic foam.

Sandbag/Gauze

Positioning Devices

Protective ApparelUsed mainly to absorb scatter radiation

Made of leadGownsGlovesThyroid shieldsGlasses

Suit Up!

Care of ApparelFigures 3-11, 3-12, Pages 32-33

It is important to keep the apron on a stand and the gloves well aerated when not in use to increase the useful life of the apron and gloves.

Figure 3-11, Page 32 – A, Vertical storage of lead aprons and gloves. B, Lead gloves stored in a horizontal position with cans placed inside to allow air circulation. C, Lead aprons draped over a “homemade” hanger. The hanger consists of a cylindrical tube that is 4 inches or greater in diameter.

Figure 3-12, Page 33 Radiograph of a lead glove showing a crack in the lead lining.

Out of Primary Beam!

Equine Extremity X-rays

Large animal radiography unit with special film cassette holders for equine extremities.

The 4 Pillars of Veterinary Radiation Safety

from http://www.animalinsides.com TimeDistanceShieldingCommon Sense

Time

Distance

Shielding

Common Sense

Radiation Safety ProgramFundamental – have one! If you don’t have one – develop oneProper Planning Prevents Poor

Performance – (PPPPP)

Radiation Safety Program6 items minimum

Adequate technique chart Positioning aids Protective clothing Personnel dosimetry devices Quality control Emergency procedures

Does Your

DAWG Miss YOU When

You Are Gone?