title: Quality assurance in diagnostic ultrasound.
abstract: OBJECTIVE
  To setup a practical ultrasound quality assurance protocol in a large radiological center, results from transducer tests, phantom measurements and visual checks for physical faults were compared.
  
  
  METHODS
  Altogether 151 transducers from 54 ultrasound scanners, from seven different manufacturers, were tested with a Sonora FirstCall aPerio™ system (Sonora Medical Systems, Inc., Longmont, CO, USA) to detect non-functional elements. Phantom measurements using a CIRS General Purpose Phantom Model 040 (CIRS Tissue Simulation and Phantom Technology, VA, USA) were available for 135 transducers. The transducers and scanners were also checked visually for physical faults. The percentages of defective findings in these tests were computed.
  
  
  RESULTS
  Defective results in the FirstCall tests were found in 17% of the 151 transducers, and in 16% of the 135 transducers. Defective image quality resulted with 15% of the transducers, and 25% of the transducers had a physical flaw. In 16% of the scanners, a physical fault elsewhere than in the transducer was found. Seven percent of the transducers had a concurrent defective result both in the FirstCall test and in the phantom measurements, 8% in the FirstCall test and in the visual check, 4% in the phantom measurements and in the visual check, and 2% in all three tests.
  
  
  CONCLUSIONS
  The tested methods produced partly complementary results and seemed all to be necessary. Thus a quality assurance protocol is forced to be rather labored, and therefore the benefits and costs must be closely followed.
authors.affiliation: HUS Helsinki Medical Imaging Center, Helsinki University Central Hospital, and Department of Physics, University of Helsinki, P.O. Box 340, 00029 HUS, Finland. outi.sipila@hus.fi
authors.forename: Outi
authors.initials: O
authors.lastname: Sipilä
authors.forename: Vilma
authors.initials: V
authors.lastname: Mannila
authors.forename: Eija
authors.initials: E
authors.lastname: Vartiainen
mesh_terms: D019544:Equipment Failure Analysis; D006801:Humans; D019047:Phantoms, Imaging; D011785:Quality Assurance, Health Care; D014159:Transducers; D014463:Ultrasonography / Q000592:standards*