title: Comparison of extraarticular leakage values of radiopharmaceuticals used for radionuclide synovectomy.
abstract: OBJECTIVE
  Radionuclide synovectomy is a reliable therapy in patients with chronic synovitis. However, radiation doses delivered to non-target organ systems due to leakage of radioactive material from the articular cavity are an important disadvantage of this procedure. In this study we compared extraarticular leakage values of the 3 commonly used radiopharmaceuticals; 90Y-citrate, 90Y-silicate and 186Re-sulfide colloid.
  
  
  METHODS
  Thirty-five patients with persistent synovitis were enrolled in the study. Twenty-two hemophilic, 8 rheumatoid arthritis and 5 patients with pigmented villonodular synovitis were studied. 90Y labeled silicate and citrate were used for knee joints and 186Re-sulfide for intermediate sized joints. Radiocolloid leakage values were evaluated using a gamma camera with 20% window centered over the bremsstrahlung photopeak of 90Y and a respective window over the 137 keV photopeak of 186Re. Regions of interest were drawn over the injection site, the regional lymph nodes and the background areas. Leakage of radiocolloid was calculated by dividing the counts/pixel in the regional lymph node area to the counts/pixel in the injection site.
  
  
  RESULTS
  No visible leakage was observed. The median leakage values calculated for 90Y-citrate, 90Y-silicate and 186Re-sulfide were found as 1.9%, 2.4% and 2.7%, respectively. The difference between the variability of leakage values was not statistically significant (p > 0.05).
  
  
  CONCLUSIONS
  There was no significant difference in terms of extraarticular leakage between 9Y-citrate, 9Y-silicate and 186Re-sulfide radiocolloids.
authors.affiliation: Department of Nuclear Medicine, Hacettepe University, Faculty of Medicine, Ankara, Turkey. goncak@hacettepe.edu.tr
authors.forename: Gonca Kara
authors.initials: GK
authors.lastname: Gedik
authors.forename: Omer
authors.initials: O
authors.lastname: Uğur
authors.forename: Bülent
authors.initials: B
authors.lastname: Atilla
authors.forename: Murat
authors.initials: M
authors.lastname: Pekmezci
authors.forename: Mustafa
authors.initials: M
authors.lastname: Yildirim
authors.forename: Bedri
authors.initials: B
authors.lastname: Seven
authors.forename: Erhan
authors.initials: E
authors.lastname: Varoğlu
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000000981:diagnostic imaging* / Q000209:etiology / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011868:Radioisotopes / Q000009:adverse effects / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000009:adverse effects / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D012720:Severity of Illness Index; D013585:Synovitis / Q000378:metabolism / Q000532:radiotherapy*; D014018:Tissue Distribution
chemical_list: D011868:Radioisotopes; D019275:Radiopharmaceuticals