Quality assurance

Published on 12/06/2015 by admin

Filed under Radiology

Last modified 12/06/2015

Print this page

This article have been viewed 998 times

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

Related

Digital and Radiographic Imaging A Practical Approach