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Calibration of Traceable Solid Mock (131)I Phantoms Used in an International SPECT Image Quantification Comparison.

Zimmerman BE, Pibida L, King LE, Bergeron DE, Cessna JT, Mille MM - J Res Natl Inst Stand Technol (2013)

Bottom Line: For this study, we designed a set of solid cylindrical sources so that each site could have a set of phantoms (having nominal volumes of 2 mL, 4 mL, 6 mL, and 23 mL) with traceable activity calibrations so that the results could be properly compared.We also developed a technique using two different detection methods for individually calibrating the sources for (133)Ba activity based on a National standard.This methodology allows for the activity calibration of each (133)Ba source with a standard uncertainty on the activity of 1.4 % for the high-level 2-, 4-, and 6-mL sources and 1.7 % for the lower-level 23 mL cylinders.

View Article: PubMed Central - PubMed

Affiliation: National Institute of Standards and Technology, Gaithersburg, MD 20899.

ABSTRACT
The International Atomic Energy Agency (IAEA) has organized an international comparison to assess Single Photon Emission Computed Tomography (SPECT) image quantification capabilities in 12 countries. Iodine-131 was chosen as the radionuclide for the comparison because of its wide use around the world, but for logistical reasons solid (133)Ba sources were used as a long-lived surrogate for (131)I. For this study, we designed a set of solid cylindrical sources so that each site could have a set of phantoms (having nominal volumes of 2 mL, 4 mL, 6 mL, and 23 mL) with traceable activity calibrations so that the results could be properly compared. We also developed a technique using two different detection methods for individually calibrating the sources for (133)Ba activity based on a National standard. This methodology allows for the activity calibration of each (133)Ba source with a standard uncertainty on the activity of 1.4 % for the high-level 2-, 4-, and 6-mL sources and 1.7 % for the lower-level 23 mL cylinders. This level of uncertainty allows for these sources to be used for the intended comparison exercise, as well as in other SPECT image quantification studies.

No MeSH data available.


Plot of experimental and theoretically calculated relative response for 133Ba solution filled cylinders in the NIST Vinten 671 ionization chamber (VIC). For the experimental data (solid diamonds), the relative response, R(norm), is defined as the ratio of the average measured ionization current per unit activity (in A/Bq) for all sources in a particular volume set to that of the average measured ionization current for the sources having a nominal volume of 6 mL. For the theoretical data (open triangles), the relative response is given as the ratio of the dose per particle calculated from the DOSRZnrc simulations for each volume to that of the dose per particle calculated for the source having a nominal volume of 6 mL. All uncertainty bars correspond to single (k = 1) uncertainty intervals and their method of evaluation is described in Sec. 3.3.
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f5-jres.118.017: Plot of experimental and theoretically calculated relative response for 133Ba solution filled cylinders in the NIST Vinten 671 ionization chamber (VIC). For the experimental data (solid diamonds), the relative response, R(norm), is defined as the ratio of the average measured ionization current per unit activity (in A/Bq) for all sources in a particular volume set to that of the average measured ionization current for the sources having a nominal volume of 6 mL. For the theoretical data (open triangles), the relative response is given as the ratio of the dose per particle calculated from the DOSRZnrc simulations for each volume to that of the dose per particle calculated for the source having a nominal volume of 6 mL. All uncertainty bars correspond to single (k = 1) uncertainty intervals and their method of evaluation is described in Sec. 3.3.

Mentions: The VIC calibration factors for the solution filled cylinders, normalized to the value at 6 mL, are plotted along with the response as calculated from the DOSRZnrc simulations, also relative to the value at 6 mL, in Fig. 5. Excellent agreement between the experimental and theoretical response is obtained for the 4 mL, 6 mL, and 23 mL cylinders, while the agreement at 2 mL can be considered reasonable, given the large uncertainties associated with the experimental measurement.


Calibration of Traceable Solid Mock (131)I Phantoms Used in an International SPECT Image Quantification Comparison.

Zimmerman BE, Pibida L, King LE, Bergeron DE, Cessna JT, Mille MM - J Res Natl Inst Stand Technol (2013)

Plot of experimental and theoretically calculated relative response for 133Ba solution filled cylinders in the NIST Vinten 671 ionization chamber (VIC). For the experimental data (solid diamonds), the relative response, R(norm), is defined as the ratio of the average measured ionization current per unit activity (in A/Bq) for all sources in a particular volume set to that of the average measured ionization current for the sources having a nominal volume of 6 mL. For the theoretical data (open triangles), the relative response is given as the ratio of the dose per particle calculated from the DOSRZnrc simulations for each volume to that of the dose per particle calculated for the source having a nominal volume of 6 mL. All uncertainty bars correspond to single (k = 1) uncertainty intervals and their method of evaluation is described in Sec. 3.3.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4487311&req=5

f5-jres.118.017: Plot of experimental and theoretically calculated relative response for 133Ba solution filled cylinders in the NIST Vinten 671 ionization chamber (VIC). For the experimental data (solid diamonds), the relative response, R(norm), is defined as the ratio of the average measured ionization current per unit activity (in A/Bq) for all sources in a particular volume set to that of the average measured ionization current for the sources having a nominal volume of 6 mL. For the theoretical data (open triangles), the relative response is given as the ratio of the dose per particle calculated from the DOSRZnrc simulations for each volume to that of the dose per particle calculated for the source having a nominal volume of 6 mL. All uncertainty bars correspond to single (k = 1) uncertainty intervals and their method of evaluation is described in Sec. 3.3.
Mentions: The VIC calibration factors for the solution filled cylinders, normalized to the value at 6 mL, are plotted along with the response as calculated from the DOSRZnrc simulations, also relative to the value at 6 mL, in Fig. 5. Excellent agreement between the experimental and theoretical response is obtained for the 4 mL, 6 mL, and 23 mL cylinders, while the agreement at 2 mL can be considered reasonable, given the large uncertainties associated with the experimental measurement.

Bottom Line: For this study, we designed a set of solid cylindrical sources so that each site could have a set of phantoms (having nominal volumes of 2 mL, 4 mL, 6 mL, and 23 mL) with traceable activity calibrations so that the results could be properly compared.We also developed a technique using two different detection methods for individually calibrating the sources for (133)Ba activity based on a National standard.This methodology allows for the activity calibration of each (133)Ba source with a standard uncertainty on the activity of 1.4 % for the high-level 2-, 4-, and 6-mL sources and 1.7 % for the lower-level 23 mL cylinders.

View Article: PubMed Central - PubMed

Affiliation: National Institute of Standards and Technology, Gaithersburg, MD 20899.

ABSTRACT
The International Atomic Energy Agency (IAEA) has organized an international comparison to assess Single Photon Emission Computed Tomography (SPECT) image quantification capabilities in 12 countries. Iodine-131 was chosen as the radionuclide for the comparison because of its wide use around the world, but for logistical reasons solid (133)Ba sources were used as a long-lived surrogate for (131)I. For this study, we designed a set of solid cylindrical sources so that each site could have a set of phantoms (having nominal volumes of 2 mL, 4 mL, 6 mL, and 23 mL) with traceable activity calibrations so that the results could be properly compared. We also developed a technique using two different detection methods for individually calibrating the sources for (133)Ba activity based on a National standard. This methodology allows for the activity calibration of each (133)Ba source with a standard uncertainty on the activity of 1.4 % for the high-level 2-, 4-, and 6-mL sources and 1.7 % for the lower-level 23 mL cylinders. This level of uncertainty allows for these sources to be used for the intended comparison exercise, as well as in other SPECT image quantification studies.

No MeSH data available.