title: [Reliability of plural measuring instruments for quantitative PET measurement -performance of dose-calibrator, auto well gamma counter, continuous blood sampling system, and PET scanner].
abstract: OBJECTIVE
  Positron emission tomography (PET) is a powerful tool for measuring in vivo functions such as blood flow, metabolism, enzyme activity, receptors, and transporters. However, plural measuring instruments (i.e., the dose-calibrator, the auto well gamma counter, the continuous blood sampling system) are necessary for the quantitative PET measurement as well as the PET scanner. The purpose of this study was to investigate the reliability of plural measuring instruments from the maintenance data for 6 years.
  
  
  METHODS
  Four kinds of measuring instrument were evaluated: a dose-calibrator (CAPINTEC, CRC-15R), an auto well gamma counter (ALOKA, ARC-400), a continuous blood sampling system (ESPEC Techno, PH type), and a dedicated PET scanner (Siemens, ECAT EXACT HR+). We examined whether the initial performance for system sensitivity is maintained. The reliability of the PET scanner was evaluated from the value of mean time between failures (MTBF) for each part of the system obtained from the maintenance data for 6 years.
  
  
  RESULTS
  The sensitivity of a dose-calibrator and an auto well gamma counter were maintained virtually constant during the 6 years, but the sensitivity of a continuous blood sampling system was 0.1+/-3.2%. The sensitivity of a PET scanner was decreased to 92.3% of the initial value. Fifty-one percent of the problems with the PET scanner were for detector block (DB) and analog processor (AP) board. The MTBF of DB and AP board module were 199 and 244 days, respectively. The MTBF of the PET scanner was 56 days.
  
  
  CONCLUSIONS
  The performance of three measuring instruments, excepting the PET scanner, was relatively stable. The reliability of the PET scanner strongly depends on the MTBF of the DB and AP board. For quantitative PET measurement, it is effective to evaluate the reliability of the system and to make it known to the users.
authors.affiliation: Faculty of Medical Science, Kyoto College of Medical Science.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Seiichi
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Wada
authors.forename: Keiji
authors.initials: K
authors.lastname: Shimizu
authors.forename: Kenya
authors.initials: K
authors.lastname: Murase
authors.forename: Michio
authors.initials: M
authors.lastname: Senda
mesh_terms: D002138:Calibration; D006801:Humans; D049268:Positron-Emission Tomography / Q000295:instrumentation*; D011868:Radioisotopes / Q000097:blood*; D011874:Radiometry / Q000295:instrumentation* / Q000592:standards; D012588:Scintillation Counting; D012680:Sensitivity and Specificity
chemical_list: D011868:Radioisotopes