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VCA 252 Principles of Diagnostic Imaging. Dr. LeeAnn Pack 566-0841, 566-0920 Lpack@upei.ca. The Discovery of X rays. Wilhelm Conrad Roentgen November 8 1895 While working in his lab - saw the glow coming from a phosphorescent screen Imaged his wife’s hand 1901 Nobel Prize for Physics.
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VCA 252 Principles of Diagnostic Imaging Dr. LeeAnn Pack 566-0841, 566-0920 Lpack@upei.ca
The Discovery of X rays • Wilhelm Conrad Roentgen • November 8 1895 • While working in his lab - saw the glow coming from a phosphorescent screen • Imaged his wife’s hand • 1901 Nobel Prize for Physics www.upei.ca/~vetrad
Radiology/Radiologist The History • ARRS RSNA • Individuals who looked at plates and compared them to the sx and autopsy findings • ACR - Radiologist – now with multiple areas of specialty • ACVR – the veterinary college www.upei.ca/~vetrad
THE Journal • Journal which highlights veterinary diagnostic imaging www.upei.ca/~vetrad
Forms of Diagnostic Imaging • Diagnostic Radiology/Radiography • X-rays used to produce image, transmitted through patient • Static images • Dynamic images fluoroscopy • Contrast agents used • Barium, Iodine examples of studies www.upei.ca/~vetrad
Forms of Diagnostic Imaging • Ultrasonography • Uses sound waves to produce image, transmitted • Sending out and listening for echoes • Internal architecture • Dynamic, US can not penetrate air or bone • Operator dependent www.upei.ca/~vetrad
Forms of Diagnostic Imaging • Computed Tomography • Uses X-rays to produce an image, transmitted • Cross sectional imaging • No superimposition of structures • Requires computer manipulation of images www.upei.ca/~vetrad
Forms of Diagnostic Imaging • Nuclear Scintigraphy • Uses gamma rays to produce an image, emitted from the patient • Radioactive nuclide given IV, per os, per rectum etc. • Abnormal function, metabolic activity, abnormal amount of uptake • Poor for anatomical information www.upei.ca/~vetrad
Forms of Diagnostic Imaging • Magnetic Resonance Imaging • Uses a strong magnetic field and radiofrequency waves to image structures • No ionizing radiation • Hydrogen protons – water • Cross sectional imaging • Great for soft tissue www.upei.ca/~vetrad
Forms of Diagnostic Imaging • Radiation Therapy • Uses radiation to treat and palliate neoplastic and some benign diseases • Cobalt • Linear Accelerators • Must have special training www.upei.ca/~vetrad
What is an X ray?Production of X rays • Form of EM radiation • All forms move at the speed of light • Vary in energy and wavelength • They penetrate matter • Can cause fluorescence of some atoms • Can expose film • Can cause biological damage www.upei.ca/~vetrad
The X ray Tube • Cathode – is the electron source • Tungsten filament • Negatively charged concave cup around filament • Focal spot • Thermonic emission – current applied wire heats up and electrons escape www.upei.ca/~vetrad
The X ray Tube • Anode – is the target which electrons strike • Tungsten target • Stationary • Anode in large block of copper – lots of heat • Used in portable units • Rotating • Disc rotates which spreads electrons around the target thus less heat build up www.upei.ca/~vetrad
The X ray Tube Note the various components and remember what they do. www.upei.ca/~vetrad
Anode Heel Effect • The surface of the anode is angled • Allows for better cooling and maintains detail • X rays on cathode side more intense • How would this be used in practice? www.upei.ca/~vetrad
The Rest • Exit window • Housing • Filtration – radiation safety • Collimation www.upei.ca/~vetrad
mAs • Milliampere-second • Milliampere -> current applied to the filament • Seconds -> time current was applied • mAs determines Quantity of X rays www.upei.ca/~vetrad
kVp • Kilovoltage peak • Determines the speed of electrons as they hit the target • Higher speed -> more power • Higher speed -> increases number of x rays • kVp determines Quality of X rays www.upei.ca/~vetrad