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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.


Full-energy-peak efficiencies for the four HPGe detectors used in the measurements of the liquid-filled vials. The uncertainty bars correspond to a single uncertainty interval (k = 1) calculated as described in Sec. 3.2.
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f2-jres.118.017: Full-energy-peak efficiencies for the four HPGe detectors used in the measurements of the liquid-filled vials. The uncertainty bars correspond to a single uncertainty interval (k = 1) calculated as described in Sec. 3.2.

Mentions: The measured full-energy-peak efficiencies for the liquid-filled sources are shown graphically in Fig. 2. The uncertainty bars on the plot represent standard uncertainties as obtained using Eq. (2). The correction factors that were applied to the measured efficiency values (for each HPGe detector) to account for the geometrical differences (i.e., differences in solution fill-height in the cylinder) between the liquid-filled cylinders and the epoxy-filled cylinders, and the self-attenuation due to difference in the liquid and epoxy densities are listed in Tables 1 through 4. Although the full-energy-peak efficiencies were calculated over the entire energy ranges shown in Fig. 2, only the decay energies given in Tables 1–4 were used in the actual determination of the 133Ba activity.


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)

Full-energy-peak efficiencies for the four HPGe detectors used in the measurements of the liquid-filled vials. The uncertainty bars correspond to a single uncertainty interval (k = 1) calculated as described in Sec. 3.2.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2-jres.118.017: Full-energy-peak efficiencies for the four HPGe detectors used in the measurements of the liquid-filled vials. The uncertainty bars correspond to a single uncertainty interval (k = 1) calculated as described in Sec. 3.2.
Mentions: The measured full-energy-peak efficiencies for the liquid-filled sources are shown graphically in Fig. 2. The uncertainty bars on the plot represent standard uncertainties as obtained using Eq. (2). The correction factors that were applied to the measured efficiency values (for each HPGe detector) to account for the geometrical differences (i.e., differences in solution fill-height in the cylinder) between the liquid-filled cylinders and the epoxy-filled cylinders, and the self-attenuation due to difference in the liquid and epoxy densities are listed in Tables 1 through 4. Although the full-energy-peak efficiencies were calculated over the entire energy ranges shown in Fig. 2, only the decay energies given in Tables 1–4 were used in the actual determination of the 133Ba activity.

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.