Course Set-up • 5 Lessons (Webinars) • 5 Lesson Exams • Final Proctored Exam • Required Reading • Diagnostic Imaging Study Guide • Radiography in Veterinary Technology (Lavin – 4th edition)
Studying for Exams • Make copy of Lesson PowerPoints • Take excellent notes during Webinars • Read & highlight Assigned Readings in Study Guide & Lavin book • Perform Self Checks in Study Guide • Learn the Glossaryat the beginning of each Chapter in Lavin book • Study Key Points & Review Questionsat end of each Chapter in Lavin book
Reading Prefaces to Lavin Textbook Why?????
Online Resources Animal Insides Veterinary E-News Magazine
Veterinary E-News Magazinehttp://www.vetxray.com/dyncat.cfm?catid=1393
2 Major Goals in Course • Learn how to take quality “Diagnostic X-rays” with minimum retakes • Learn Radiation Safety • Staff • Animal
What Are X-rays? • Definition • X-rays are a form of electromagnetic radiation similar to visible light, but with a much shorter wavelength
Physical Properties of X-rays • Wavelength • Travel • Straight lines • Speed of light • Fluorescence • Captured on film • Biologic changes in living tissue
Taking X-rays Exposure Factors Control Panel X-ray Machine
Exposure Factors • Milliamperage (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)
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-raymachine 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
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 sideof the x-ray beam because of the angle of the anode target area.
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.
Black & White on Films • Black – x-rays NOT absorbed by animal’s body….. End up hitting film • White – x-rays absorbed by animal’s body…. Fewer get to film
Collimator • Made of lead • Restricts (collimates) SIZE of primary x-ray beam • Limits patient & staff exposure to beam • Increases quality of x-ray beam • Less secondary (scatter) radiation • Does NOT intensify primary x-ray beam • Permanent & adjustable types
How Much to Collimate? • Ideally, every film should have a collimated edge around the entire film • Use of a smaller cassette is another means of collimating
Ionizing Radiation • Definition • 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!