title: Validation of novel calibration scheme with traceable point-like (22)Na sources on six types of PET scanners.
abstract: OBJECTIVE
  To improve the reliability and convenience of the calibration procedure of positron emission tomography (PET) scanners, we have been developing a novel calibration path based on traceable point-like sources. When using (22)Na sources, special care should be taken to avoid the effects of 1.275-MeV γ rays accompanying β (+) decays. The purpose of this study is to validate this new calibration scheme with traceable point-like (22)Na sources on various types of PET scanners.
  
  
  METHODS
  Traceable point-like (22)Na sources with a spherical absorber design that assures uniform angular distribution of the emitted annihilation photons were used. The tested PET scanners included a clinical whole-body PET scanner, four types of clinical PET/CT scanners from different manufacturers, and a small-animal PET scanner. The region of interest (ROI) diameter dependence of ROI values was represented with a fitting function, which was assumed to consist of a recovery part due to spatial resolution and a quadratic background part originating from the scattered γ rays.
  
  
  RESULTS
  The observed ROI radius dependence was well represented with the assumed fitting function (R (2) > 0.994). The calibration factors determined using the point-like sources were consistent with those by the standard cross-calibration method within an uncertainty of ±4 %, which was reasonable considering the uncertainty in the standard cross-calibration method.
  
  
  CONCLUSIONS
  This novel calibration scheme based on the use of traceable (22)Na point-like sources was successfully validated for six types of commercial PET scanners.
authors: Allied Health Sciences, Kitasato University, Kitasato 1-15-1, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan. hasegawa@kitasato-u.ac.jp
authors: Tomoyuki
authors: T
authors: Hasegawa
authors: Keiichi
authors: K
authors: Oda
authors: Yasuhiro
authors: Y
authors: Wada
authors: Toshiaki
authors: T
authors: Sasaki
authors: Yasushi
authors: Y
authors: Sato
authors: Takahiro
authors: T
authors: Yamada
authors: Mikio
authors: M
authors: Matsumoto
authors: Hideo
authors: H
authors: Murayama
authors: Kei
authors: K
authors: Kikuchi
authors: Hiroki
authors: H
authors: Miyatake
authors: Yutaka
authors: Y
authors: Abe
authors: Kenta
authors: K
authors: Miwa
authors: Kenta
authors: K
authors: Akimoto
authors: Kei
authors: K
authors: Wagatsuma
mesh_terms: D000465:Algorithms; D002138:Calibration; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007564:Japan; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000592:standards*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012979:Sodium Radioisotopes / Q000032:analysis* / Q000592:standards*
chemical_list: D012979:Sodium Radioisotopes