Uncertainty of nuclear counting

Pommé, S.; Fitzgerald, R.; Keightley, J D

doi:10.1088/0026-1394/52/3/s3

Cited by 56 publications

(39 citation statements)

References 46 publications

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“…Counting is unlike any other measurement procedure and usually implies a zero uncertainty (but not always [36] In measurements that assign a number of moles to a quantity, counting is not actually involved.…”

Section: Prevalence Of Counting In Software Metricsmentioning

confidence: 99%

A Rational Foundation for Software Metrology

Flater¹,

Black²,

Fong³

et al. 2016

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Section: Prevalence Of Counting In Software Metricsmentioning

confidence: 99%

A Rational Foundation for Software Metrology

Flater¹,

Black²,

Fong³

et al. 2016

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“…For the same injection with 99m Tc, the rate could be 320 kcps, but the detector software limits output to 250 kcps. Based on the linearity testing done in this work, nonlinearity was within the range expected for pile‐up‐based effects …”

Section: Discussionmentioning

confidence: 58%

Technical Note: Characterization of technology to detect residual injection site radioactivity

et al. 2019

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PurposeEach year in the United States, approximately 18.5 million nuclear medicine procedures are performed. Various quality control measures are implemented to reduce image errors and improve quantification of radiotracer distribution. However, there is currently no routine or timely feedback about the quality of the radiotracer injection. One potential solution to evaluate the injection quality is to place a topical scintillation sensor near the injection site to record the presence of residual activity. This work investigates a sensor design for identification of injections where the prescribed radioactive activity is not fully delivered into the patient's circulation (an infiltration).MethodsThe sensor consists of a single unshielded bismuth germanate (BGO) crystal (3 mm × 3 mm × 3 mm). Using radioactive sources with gamma energies that span the range commonly used in nuclear medicine, we quantified energy resolution and linearity. Additionally, we computed sensitivity by comparing the calculated incident activity to the activity measured by the sensor. Sensor output linearity was calculated by comparing measured data against the radioactive decay of a source over multiple half‐lives. The sensor incorporates internal temperature feedback used to compensate for ambient temperature fluctuations. We investigated the performance of this compensation over the range of 15°C–35°C.ResultsEnergy spectra from four sensors were used to calculate the energy resolution: 67% for 99mTc (141 keV), 67% for 133Ba (344 keV), 42% for 18F (511 keV), and 32% for 137Cs (662 keV). Note that the energy used for 133Ba is a weighted average of the three photon emissions nearest to the most abundant (356 keV). Sensor energy response was linear with a difference of 1%–2% between measured and predicted values. Energy‐dependent detector sensitivity, defined as the ratio of measured photons to incident photons for a given isotope, decreased with increasing photon energy from 55.4% for 99mTc (141 keV) to 3.3% for 137Cs (662 keV). Without compensation, error due to temperature change was as high as 53%. Temperature compensation reduced the error to less than 1.4%. Sensor output linearity was tested to as high as 210 kcps and the maximum magnitude error was 4%.ConclusionsThe performance of the sensor was adequate for identification of excessive residual activity at an injection site. Its ability to provide feedback may be useful as a quality control measure for nuclear medicine injections.

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“…A system could have mixed dead time, which is not considered further here, beyond noting that by designing a counting system with an imposed, extending dead-time that is longer than any intrinsic dead time of the system, one can approximate the pure extending dead-time case. The uncertainties from various dead-time, pileup, and live-time corrections are the subject of a recent review article (Pommé et al, 2015), which indeed cites the final result of this paper.…”

Section: Introductionmentioning

confidence: 73%

Corrections for the combined effects of decay and dead time in live-timed counting of short-lived radionuclides

Fitzgerald

2016

Applied Radiation and Isotopes

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Studies and calibrations of short-lived radionuclides, for example 15O, are of particular interest in nuclear medicine. Yet counting experiments on such species are vulnerable to an error due to the combined effect of decay and dead time. Separate decay corrections and dead-time corrections do not account for this issue. Usually counting data are decay-corrected to the start time of the count period, or else instead of correcting the count rate, the mid-time of the measurement is used as the reference time. Correction factors are derived for both those methods, considering both extending and non-extending dead time. Series approximations are derived here and the accuracy of those approximations are discussed.

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Uncertainty of nuclear counting

Cited by 56 publications

References 46 publications

A Rational Foundation for Software Metrology

A Rational Foundation for Software Metrology

Technical Note: Characterization of technology to detect residual injection site radioactivity

Corrections for the combined effects of decay and dead time in live-timed counting of short-lived radionuclides

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