title: Biodistribution and radiodosimetry of a novel myocardial perfusion tracer 123I-CMICE-013 in healthy rats.
abstract: BACKGROUND
  123I-CMICE-013 is a novel radiotracer previously reported to have promising characteristics for single-photon emission computed tomography (SPECT) myocardial perfusion imaging. We evaluated the biokinetics and radiodosimetry of this rotenone-like 123I-labeled tracer in a microSPECT imaging-based study.
  
  
  METHODS
  37 to 111 MBq of 123I-CMICE-013 was synthesized and administered intravenously to 14 healthy rats. Images were acquired with a microSPECT/CT camera at various time intervals and reconstructed to allow activity quantification in the tissues of interest. Radiation dosage resulted from the injection of 123I-CMICE-013 was estimated base on the biodistribution data. Tissue uptake values from image analysis were verified by gamma-counting dissected organs ex vivo.
  
  
  RESULTS
  The heart/stomach and heart/intestine uptake ratios peaked shortly after the injection of 123I-CMICE-013, meanwhile the heart/liver ratio reached 2 as early as at 23 min post-injection. Little activity was observed in the lung and overnight clearance was significant in most of the measured tissues. The radiation dosimetry analysis based on the time-activity curves provided an estimate of the effective human dose of 6.99E-03 mSv/MBq using ICRP 60 and 7.15E-03 mSv/MBq using ICRP 103, which is comparable to the popular myocardium perfusion imaging (MPI) agents such as 99mTc-tetrofosmin and 99mTc-sestamibi, as well as other 123I-based radiotracers.
  
  
  CONCLUSIONS
  123I-CMICE-013 demonstrated desirable characteristics in its biokinetic and radiodosimetric profiles, supporting its potential application as a novel myocardial perfusion imaging agent.
authors.affiliation: Nordion Inc, 447 March Road, Ottawa, ON K2K 1X8, Canada. daniel.duan@nordion.com.
authors.forename: Yin
authors.initials: Y
authors.lastname: Duan
authors.forename: Julia
authors.initials: J
authors.lastname: Lockwood
authors.forename: Lihui
authors.initials: L
authors.lastname: Wei
authors.forename: Chad
authors.initials: C
authors.lastname: Hunter
authors.forename: Karen
authors.initials: K
authors.lastname: Soueidan
authors.forename: Corinne
authors.initials: C
authors.lastname: Bensimon
authors.forename: Pasan
authors.initials: P
authors.lastname: Fernando
authors.forename: R Glenn
authors.initials: RG
authors.lastname: Wells
authors.forename: Terrence D
authors.initials: TD
authors.lastname: Ruddy