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Indice/Contents Nº 12

ABSTRACTS PRESENTADOS AL 11th INTERNATIONAL SYMPOSIUM "RADIONUCLIDES IN NEPHRO-UROLOGY", REALIZADO EN MONTEREY, CALIFORNIA, 13-17 MAYO 2001.

 

3. DETERMINATION OF GLOMERULAR FILTRATION RATE BY MEANS OF NEWLY DEVELOPED PLASTIC SCINTILLATION COUNTER BOTH WITH AND WITHOUT DILUTION PROCEDURES.

Kazuo Itoh, Satoshi Tsushima, Yasuji Ihara, Kimikazu Sasaki, Takitsugu Oka, Takashi Kido. Department of Radiology and Internal Medicine, JR Sapporo general Hospital, Sapporo, JAPAN.

itohka51@ra2.so-net.ne.jp

 

Background: The two-well single-detector scintillation counter (DW-counter) has been developed for simplifying a plasma sample method following a single injection of radioactive markers. The DW- counter serves the two functions of a standards well counter in Well-A and a dose calibrator in Well-B. The aim of this study was to assess the clinical feasibility of the counter (DW-counter) for the estimation of GFR with Tc99m-DTPA.

 

Materials and Methods. The study was performed on 25 patients (male/female: 11/14, age range: 12-89 years, average age: 59.2+/-19 years) with various degrees of renal dysfunction. The GFR was estimated from the two equations based on radioactivity in a single plasma sample between 134 min and 220 min following a single injection of Tc99m-DTPA. Total injected dose and plasma radioactivity were calculated in two ways: standard dilution technique with a single well (dilution method) and no dilution method with two wells (direct method).

Results. The directly estimated GFR by DW-counter correlated excellently with the GFR by the dilution method (R=0.998). The dilution method tended to give slightly higher readings of GFR than the direct method. The difference in GFR between the two comparative methods was assumed to be caused by overestimation of total injected dose in the dilution methods, in which remaining radioactivity in the 3-way cock after administration was not considered in the calculation.

Conclusion. The DW-counter can circumvent laborious dilution techniques and expertise for quantifying the GFR in a single-sample method following a single injection of Tc99m-DTPA in the clinical practice. It will be an alternative to the standard dilution method.