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

PURPOSE: Each 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 abo...

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Autores principales: Knowland, Josh, Lipman, Samantha, Lattanze, Ron, Kingg, Jesse, Ryan, Kelley, Perrin, Steven
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6850203/
https://www.ncbi.nlm.nih.gov/pubmed/30972762
http://dx.doi.org/10.1002/mp.13536
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author Knowland, Josh
Lipman, Samantha
Lattanze, Ron
Kingg, Jesse
Ryan, Kelley
Perrin, Steven
author_facet Knowland, Josh
Lipman, Samantha
Lattanze, Ron
Kingg, Jesse
Ryan, Kelley
Perrin, Steven
author_sort Knowland, Josh
collection PubMed
description PURPOSE: Each 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). METHODS: The 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. RESULTS: Energy spectra from four sensors were used to calculate the energy resolution: 67% for (99m)Tc (141 keV), 67% for (133)Ba (344 keV), 42% for (18)F (511 keV), and 32% for (137)Cs (662 keV). Note that the energy used for (133)Ba 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 (99m)Tc (141 keV) to 3.3% for (137)Cs (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%. CONCLUSIONS: The 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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spelling pubmed-68502032019-11-18 Technical Note: Characterization of technology to detect residual injection site radioactivity Knowland, Josh Lipman, Samantha Lattanze, Ron Kingg, Jesse Ryan, Kelley Perrin, Steven Med Phys QUANTITATIVE IMAGING AND IMAGE PROCESSING PURPOSE: Each 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). METHODS: The 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. RESULTS: Energy spectra from four sensors were used to calculate the energy resolution: 67% for (99m)Tc (141 keV), 67% for (133)Ba (344 keV), 42% for (18)F (511 keV), and 32% for (137)Cs (662 keV). Note that the energy used for (133)Ba 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 (99m)Tc (141 keV) to 3.3% for (137)Cs (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%. CONCLUSIONS: The 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. John Wiley and Sons Inc. 2019-04-29 2019-06 /pmc/articles/PMC6850203/ /pubmed/30972762 http://dx.doi.org/10.1002/mp.13536 Text en © 2019 Lucerno Dynamics. Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine. This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc-nd/4.0/ License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
spellingShingle QUANTITATIVE IMAGING AND IMAGE PROCESSING
Knowland, Josh
Lipman, Samantha
Lattanze, Ron
Kingg, Jesse
Ryan, Kelley
Perrin, Steven
Technical Note: Characterization of technology to detect residual injection site radioactivity
title Technical Note: Characterization of technology to detect residual injection site radioactivity
title_full Technical Note: Characterization of technology to detect residual injection site radioactivity
title_fullStr Technical Note: Characterization of technology to detect residual injection site radioactivity
title_full_unstemmed Technical Note: Characterization of technology to detect residual injection site radioactivity
title_short Technical Note: Characterization of technology to detect residual injection site radioactivity
title_sort technical note: characterization of technology to detect residual injection site radioactivity
topic QUANTITATIVE IMAGING AND IMAGE PROCESSING
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6850203/
https://www.ncbi.nlm.nih.gov/pubmed/30972762
http://dx.doi.org/10.1002/mp.13536
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