Quality assurance

Published on 12/06/2015 by admin

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Last modified 12/06/2015

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11 Quality assurance

Definition of quality assurance

	A method of testing digital imaging systems to ensure consistency of results within the computer network. (See also Appendix F: Quality Assurance and Tests.)
Equipment Required	• 1 mm copper filter • 1 straight edge metal strip • Leeds Tor 18 test tool • Leeds test object N3 • Leeds test object GS2 • Leeds test object T010

Test for low contrast sensitivity and resolution

Equipment Required	• Leeds Tor 18 test object • 1 mm copper filter • 24 × 30 cm cassette • X-ray tube
Equipment Tested	• Viewing stations • Laser printers
Testing Frequency	Weekly
Testing Method	• Test tool is placed in the centre of the cassette • X-ray tube centred to the cassette • Collimators are fully opened • Copper filter placed next to the tube • Expose plate using: 100 cm, 55 kVp, 45 mAs • Process the film
Results	• View the image on the main workstation monitor • The monitor should not be adjusted • 18 discs around the inside edge of the circular image should be seen This gives the grey scale of contrast • The line pairs in the middle of the pattern are counted Note if the lines appear to merge they are not counted This gives the resolution of the system • The test is repeated on the other monitors by the same person • The test is sent to the laser printers and evaluated by the same person
Evaluation	• Using the table for testing fluoroscopic equipment • Acceptable results are: 16 discs seen, 14 line pairs 2.24 spatial frequency cycles per millimetre A difference of 3 or more discs or 3 or more line pairs indicates a problem, but note that a difference of one could be due to the eyesight of the person doing the test Buy Membership for Radiology Category to continue reading. Learn more here

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