title: Feasibility of myocardial perfusion imaging with half the radiation dose in obese patients using ordered-subset expectation maximization with resolution recovery software.
abstract: BACKGROUND
  We previously described the feasibility of myocardial perfusion imaging (MPI) with nearly half the radiation dose using ordered-subset expectation maximization with resolution recovery (OSEM-RR) processing. This study sought to determine if the findings can be expanded to obese patients.
  
  
  METHODS
  Fifty obese patients (>100 kg) referred for MPI underwent stress-rest or rest-stress studies with a half dose of Tc-99m sestamibi in a 1-day protocol using OSEM-RR processing. Image quality and clinical results were compared with matched patients (by age, sex, weight, presence/probability of coronary artery disease) evaluated with standard "full-dose" Tc-99m sestamibi, mostly in a 2-day protocol. Dose activities were adjusted individually by weight.
  
  
  RESULTS
  Mean Tc-99m activity was 33.4 ± 13.9 mCi in the half-dose group and 60 ± 10 mCi in the full-dose group (P < .0001). Respective mean effective doses per study were 10 ± 4 and 18 ± 3 mSv (P < .0001). Overall image quality was good-to-excellent in 94% of the half-dose group and 80% of the full-dose group (P < .045). There was no between-group difference in rate or size of ischemia or infarction, except for stress left ventricular ejection fraction.
  
  
  CONCLUSIONS
  MPI with half the radiation dose is feasible in obese patients. Image quality is better than for full-dose MPI, and the procedure can be performed in 1 day.
authors.affiliation: Nuclear Cardiology Unit, Department of Cardiology, Rabin Medical Center, Beilinson Campus, 49100 Petah Tikva, Israel. zafrirmd@isdn.net.il
authors.forename: Nili
authors.initials: N
authors.lastname: Zafrir
authors.forename: Tamir
authors.initials: T
authors.lastname: Bental
authors.forename: Alejandro
authors.initials: A
authors.lastname: Solodky
authors.forename: Avi
authors.initials: A
authors.lastname: Ben-Shlomo
authors.forename: Israel
authors.initials: I
authors.lastname: Mats
authors.forename: Yosef
authors.initials: Y
authors.lastname: Hassid
authors.forename: Doron
authors.initials: D
authors.lastname: Belzer
authors.forename: Alexander
authors.initials: A
authors.lastname: Battler
authors.forename: Ariel
authors.initials: A
authors.lastname: Gutstein
mesh_terms: D000368:Aged; D000465:Algorithms; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009765:Obesity / Q000150:complications* / Q000000981:diagnostic imaging*; D010477:Perfusion; D011336:Probability; D011829:Radiation Dosage; D011868:Radioisotopes; D012984:Software; D017256:Technetium Tc 99m Sestamibi; D016277:Ventricular Function, Left
chemical_list: D011868:Radioisotopes; D017256:Technetium Tc 99m Sestamibi