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Titolo:
Radioassays and experimental evaluation of dose calibrator settings for F-18
Autore:
Zimmerman, BE; Kubicek, GJ; Cessna, JT; Plascjak, PS; Eckelman, WC;
Indirizzi:
Natl Inst Stand & Technol, Phys Lab, Gaithersburg, MD 20899 USA Natl Inst Stand & Technol Gaithersburg MD USA 20899 ersburg, MD 20899 USA NIH, PET Dept, Bethesda, MD 20892 USA NIH Bethesda MD USA 20892NIH, PET Dept, Bethesda, MD 20892 USA
Titolo Testata:
APPLIED RADIATION AND ISOTOPES
fascicolo: 1, volume: 54, anno: 2001,
pagine: 113 - 122
SICI:
0969-8043(200101)54:1<113:RAEEOD>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
STANDARDIZATION; EFFICIENCY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
16
Recensione:
Indirizzi per estratti:
Indirizzo: Zimmerman, BE Natl Inst Stand & Technol, Phys Lab, Gaithersburg, MD 20899 USA Natl Inst Stand & Technol Gaithersburg MD USA 20899 899 USA
Citazione:
B.E. Zimmerman et al., "Radioassays and experimental evaluation of dose calibrator settings for F-18", APPL RAD IS, 54(1), 2001, pp. 113-122

Abstract

The positron emitter F-18 continues to be one of the most important imaging radionuclides in diagnostic nuclear medicine. Assays of radiopharmaceuticals containing this nuclide are often performed in the clinic using commercial reentrant ionization chambers, or "dose calibrators". Meaningful quantitative clinical studies require accurate knowledge of the injected activitywhich requires proper calibration of these instruments. Radioassays were performed at thr: National Institute of Standards and Technology (NIST) on asolution of F-18 produced at the National Institutes of Health (NIH) using4 pi beta liquid scintillation (fS) counting with H-3-standard efficiency tracing. Cocktails containing water fractions of approximately 0.9 and 9% (both as saline) were used. The massic activity values were measured to be 2.52 +/- 0.06 and 2.50 +/- 0.03 MBq g(-1), respectively, for the 0.9 and 9% water cocktails as of the reference time. The uncertainties on the activitymeasurements are expanded (k = 2) uncertainties. The largest uncertainty component was found to be the repeatability on a single LS source, with the cocktails containing 0.9% water fraction exhibiting a larger variability bynearly a factor of two. Reproducibility between LS cocktails with the samewater Traction was also found to be a large uncertainty component, but with a value less than half that due to measurement repeatability. Radionuclidic impurities consisted of V-48 and Sc-46, at levels of 0.11 +/- 0.08% (expanded uncertainties) and approximately 2 x 10(-3)% (upper limit) relative to the activity of the F-18, as Of the reference time. Dose calibrator dial settings for measuring solutions of]SF were experimentally determined for Capintec CRC-12 and CRC-35R dose calibrators in three measurement geometries: a 5-ml standard NIST ampoule (two ampoules measured), a 12-ml plastic syringe containing 9 mi of solution and a 10-ml Mallinckrodt molded dose vial filled with 5 mi of solution. The experimental dial settings land the corresponding expanded uncertainties) for these geometries were found to be 477 /- 7, 474 +/- 6, 482 +/- 6 and 463 +/- 7 for the two ampoules, the syringeand the dose vial, respectively, in the CRC-12, The dial settings determined for the CRC-35R were 472 +/- 7, 470 +/- 7, 464 +/- 6 and 456 +/- 6 for the two ampoules, the syringe, and the dose vial, respectively. The uncertainties in the dial settings are expanded uncertainties. Comparisons between the empirically determined.. dial settings and the manufacturer's recommended setting of "439" indicate that use of the manufacturer's setting overestimates the activity by between 3 and 6%, depending upon the geometry used. Published by Elsevier Science Ltd.

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Documento generato il 02/04/20 alle ore 01:29:40