title: Evaluation of technetium-99m-ethylenedicysteine in renal disorders and determination of extraction ratio.
abstract: This article evaluates the clinical usefulness of 99mTc-ethylenedicysteine (EC) in patients with various renal disorders. In addition, extraction ratios of 99mTc-EC in five volunteers were also determined.
  
  
  METHODS
  Twenty patients were intravenously injected with 200 MBq 99mTc-EC and 2.5 MBq [131I]orthoiodohippurate (OIH) simultaneously and 11 blood samples were withdrawn within 60 min. Plasma clearance was determined on the basis of a two-compartment model. Imaging was performed in the posterior projection by acquiring three sets of images. Extraction ratios were determined from the blood samples obtained from the renal vein and abdominal aorta.
  
  
  RESULTS
  Renal clearance of 99mTc-EC was significantly lower than that of OIH (p = 0.0003) with good correlation (r = 0.93). Volume distributions of 99mTc-EC and OIH were 26584 +/- 10807 ml/1.73 m2 and 23148 +/- 7602 ml/1.73 m2, respectively (p = 0.047). The clearance half-lives of 99mTc-EC and OIH were 98 +/- 54 min and 74 +/- 54 min, respectively (p = 0.049). Protein binding of 99mTc-EC (33 +/- 3.2%) was significantly less than that of OIH (62 +/- 2.8%) (p < 0.0001). Red blood cell binding of 99mTc-EC was almost negligible (5.7 +/- 4.3%). Similar extraction ratios were obtained from blood (0.68 +/- 0.08) and plasma (0.70 +/- 0.07) (p = 0.062). The 60-min excretion fractions were similar for 99mTc-EC and OIH, with values of 50% +/- 20% and 51% +/- 19%, respectively (p = 0.9).
  
  
  CONCLUSIONS
  Technetium-99m-EC is a suitable radiopharmaceutical for routine renal dynamic studies. Although the biological behavior of 99mTc-EC seems to be different from that of OIH, their clearances demonstrate high correlation. Technetium-99m-EC provides excellent quality images and has high potential in the evaluation of quantitative renal functions.
authors.affiliation: Department of Nuclear Medicine, Cerrahpaşa Medical Faculty of Istanbul University, Turkey.
authors.forename: L
authors.initials: L
authors.lastname: Kabasakal
authors.forename: S
authors.initials: S
authors.lastname: Atay
authors.forename: V A
authors.initials: VA
authors.lastname: Vural
authors.forename: K
authors.initials: K
authors.lastname: Ozker
authors.forename: K
authors.initials: K
authors.lastname: Sönmezoglu
authors.forename: M
authors.initials: M
authors.lastname: Demir
authors.forename: I
authors.initials: I
authors.lastname: Uslu
authors.forename: A T
authors.initials: AT
authors.lastname: Işitman
authors.forename: C
authors.initials: C
authors.lastname: Onsel
mesh_terms: D000328:Adult; D003545:Cysteine / Q000031:analogs & derivatives*; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D007465:Iodohippuric Acid; D007674:Kidney Diseases / Q000000981:diagnostic imaging*; D008297:Male; D015609:Organotechnetium Compounds; D011866:Radioisotope Renography; D014018:Tissue Distribution
chemical_list: D007457:Iodine Radioisotopes; D015609:Organotechnetium Compounds; C073806:technetium Tc 99m-ethylenedicysteine; D007465:Iodohippuric Acid; D003545:Cysteine