title: Tc-99m sulfur colloid and Tc-99m tagged red blood cell methods are comparable for detecting lower gastrointestinal bleeding in clinical practice.
abstract: OBJECTIVE
  The objective of this study was to determine whether the Tc-99m red blood cells (Tc-99m RBC) method has a true advantage over the Tc-99m sulfur colloid (Tc-99m SC) technique in a busy clinical practice for detecting and localizing lower gastrointestinal bleeding sites.
  
  
  METHODS
  Three hundred fifty-nine consecutive gastrointestinal bleeding studies performed during the past 4 years were reviewed retrospectively. One hundred ninety-three scans were obtained with Tc-99m SC (scan duration, 30 minutes) and 138 studies were performed after the administration of Tc-99m RBC (scan duration, 1 hour). In addition, 28 examinations with Tc-99m SC were followed immediately by Tc-99m RBC scans for a duration of several hours. The results of the two methods were analyzed and the performance of the two techniques was compared.
  
  
  RESULTS
  Among 193 scans performed using the Tc-99m SC method, 47 (24.4%) successfully identified the location of the bleeding site, whereas in 138 scans performed using Tc-99m RBC, 38 (27.5%) were successful for this purpose. In the remaining 28 scans in which the Tc-99m SC scan was followed by the Tc-99m RBC study, only 4 (14.3%) positive bleeding sites were identified after a prolonged imaging period.
  
  
  CONCLUSIONS
  The theoretical advantages of the Tc-99m RBC technique compared with the Tc-99m SC method cannot be substantiated by this study. Our findings suggest that the efficacy of these two methods is nearly equal at a practical level.
  
  
  CONCLUSIONS
  The simpler and cost-effective Tc-99m SC method is as efficient as the Tc-99m RBC method when the scanning time is limited to 1 hour and optimal imaging and interpretation schemes are used.
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Fabio
authors.initials: F
authors.lastname: Ponzo
authors.forename: Hongming
authors.initials: H
authors.lastname: Zhuang
authors.forename: Frank M
authors.initials: FM
authors.lastname: Liu
authors.forename: Lester B
authors.initials: LB
authors.lastname: Lacorte
authors.forename: Bahar
authors.initials: B
authors.lastname: Moussavian
authors.forename: Sunny
authors.initials: S
authors.lastname: Wang
authors.forename: Abass
authors.initials: A
authors.lastname: Alavi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004912:Erythrocytes / Q000000981:diagnostic imaging*; D006471:Gastrointestinal Hemorrhage / Q000097:blood* / Q000000981:diagnostic imaging*; D006801:Humans; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013670:Sodium Pertechnetate Tc 99m; D013671:Technetium Tc 99m Sulfur Colloid / Q000494:pharmacology; D013997:Time Factors
chemical_list: D019275:Radiopharmaceuticals; D013671:Technetium Tc 99m Sulfur Colloid; D013670:Sodium Pertechnetate Tc 99m