title: Validation of a postinjection transmission method for actual rat brain PET.
abstract: OBJECTIVE
  Postinjection transmission positron emission tomography (PET) may be useful for shortening the total scan time. In this study, the effect of post-transmission scanning was assessed using PET on a phantom (NU4) and actual rat brain.
  
  
  METHODS
  Transmission was performed using (57)Co for 15 min. After a 15-min pre-transmission scan, emission PET was performed in list mode for 1 h, followed by an additional 15-min post-transmission scan. To compare the pre-transmission and post-transmission results, we measured nonuniformity, the recovery coefficient, and the spillover ratio (SOR) using NU4 and rat phantoms. The authors also assessed cerebral glucose metabolism using (18)F-fluorodeoxyglucose (FDG) PET and the binding potential for (18)F-fluorinated N-3-fluoropropyl-2-β-carboxymethoxy-3-β-(4-iodophenyl)nortropane (FP-CIT) in rat brain for differences between pre-transmission and post-transmission scanning.
  
  
  RESULTS
  Nonuniformity and the SORs for air and water were comparable on the pre-transmission and post-transmission scans. With FDG-PET, after attenuation and scatter corrections no differences were observed in the brain regions on the pre-transmission and post-transmission scans. With FP-CIT-PET, the binding potentials were also not significantly different.
  
  
  CONCLUSIONS
  In the present study, we validated a post-transmission method for PET of the rat brain. Post-transmission PET was reliable, and the results were comparable to those of pre-transmission PET. Post-transmission PET eliminates the early tracer uptake time in the PET imaging, making it possible to determine uptake in the conscious subject, which may provide more realistic, "normal" metabolic measurements. Thus, post-transmission PET may be a useful option for increasing the number of subjects who can be evaluated.
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea. kjs@kirams.re.kr
authors.forename: Jin Su
authors.initials: JS
authors.lastname: Kim
authors.forename: A Ram
authors.initials: AR
authors.lastname: Yu
authors.forename: Kyeong Min
authors.initials: KM
authors.lastname: Kim
authors.forename: Seung Jun
authors.initials: SJ
authors.lastname: Oh
authors.forename: Jin Sook
authors.initials: JS
authors.lastname: Ryu
authors.forename: Hee-Joung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Sang Moo
authors.initials: SM
authors.lastname: Lim
mesh_terms: D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging*; D019788:Fluorodeoxyglucose F18; D007267:Injections; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014326:Tropanes
chemical_list: D014326:Tropanes; D019788:Fluorodeoxyglucose F18; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane