title: Computed tomography x-ray tube life analysis: a multiyear study.
abstract: OBJECTIVE
  To assess and compare actual computed tomography (CT) x-ray tube life with manufacturer warranty coverage limits because prolonging the tube life helps to lower operating costs.
  
  
  METHODS
  Ten GE LightSpeed CT scanners with 40 Performix Ultra tube changes and 3 GE VCT scanners with 10 Performix Pro tube changes were followed for 6 years. CT x-ray tube life measurements were performed by analyzing log files of the units after a tube change.
  
  
  RESULTS
  The Ultra tubes warranty coverage limit is 70 kAs or 12 months, whichever comes first. For Pro tubes, it is 6000 examinations or 12 months, whichever comes first. Measurements for the Performix Ultra CT x-ray tubes showed a range of 7 to 48 months and 16.7 to 239.9 kAs. Mean values for the Ultra CT x-ray tubes were 19.2 ± 12.5 months and 81.0 ± 45.4 kAs. Seven Ultra CT x-ray tubes did not meet the warranty coverage limits, with an average life of 8 months and 48.1 kAs. For the Pro CT x-ray tubes, the measured logs indicated 22.4 ± 9.6 months of CT x-ray tube life. All 10 Pro CT x-ray tubes exceeded company warranty coverage limits.
  
  
  CONCLUSIONS
  Although Pro tubes lasted longer, they acquired fewer scans than did Ultra tubes. A similar result was shown for current output.
  
  
  CONCLUSIONS
  Because the clinical demand for a CT scanner varies, it is difficult to determine the reason for the failed tubes. Mechanical, environmental, and usage factors can reduce the life expectancy of an x-ray tube.
authors.affiliation: Diagnostic X-Ray Quality Assurance Section, Department of Medical Physics, at Memorial Sloan-Kettering Cancer Center, New York City, USA.
authors.forename: Yusuf Emre
authors.initials: YE
authors.lastname: Erdi
mesh_terms: D004581:Electronics / Q000295:instrumentation* / Q000706:statistics & numerical data*; D004867:Equipment Design; D004868:Equipment Failure / Q000706:statistics & numerical data*; D019544:Equipment Failure Analysis; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000706:statistics & numerical data*