Abstract
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Objectives The perfusion agent 62Cu-ETS was specifically designed to overcome high blood flow limitations of the Cu-BTS compounds arising from blood plasma binding. To assess this agent in a very demanding high flow application a phase II renal imaging study is underway at the University of Wisconsin-Madison utilizing 62Zn/62Cu(9.7 min) microgenerator and kit prepared radiotracer. 15O-H2O is employed as the gold standard comparator.
Methods To date, 9 healthy volunteers and 1 dialysis patient have been studied with whole-body PET (GE Advance or Siemens HRT) with paired dynamic attenuation-corrected renal imaging using 15O-H2O (15-50 mCi) followed by 62Cu-ETS (14-25 mCi) for 90 s or 22 min, respectively. Image quality was assessed qualitatively and by comparing total tracer decays per cc during the imaging = Ao x 1.443 x T1/2 x (1 – 2(-T/T1/2)), Ao = uptake in Bq/cc at TOI, T = image duration (s).
Results High renal micro-sphere like retention of Cu-ETS was seen within 1.5 min. Renal washout half time was ~ 90 min. High contrast was seen between the renal cortex and the medulla with no evidence of urinary excretion. Image statistics comparison gave the following results.
Results The # of decays/cc in the renal cortex was 20 fold higher with 62Cu-ETS per injected mCi. Subjective and quantitative analysis revealed very low contrast in the 15O-H2O images likely resulting from low statistical content.
Conclusions The new perfusion agent 62Cu-ETS will provide substantially improved high count and high contrast renal imaging. Validation of quantitative flow measurements awaits further modeling analysis.
Research Support NIH SBIR Grants DK058466 and CA110154
- © 2009 by Society of Nuclear Medicine