Background <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$^{131}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mn>131</mn> </mmultiscripts> </math></EquationSource> </InlineEquation>I is a critical radionuclide in nuclear medicine, particularly for thyroid disorder therapies. Chinese national standards mandate reducing <InlineEquation ID="IEq5"> <EquationSource Format="TEX">$^{131}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mn>131</mn> </mmultiscripts> </math></EquationSource> </InlineEquation>I concentrations in radioactive waste liquid to below 10 Bq/L. To address this requirement, rapid and precise quantification of <InlineEquation ID="IEq6"> <EquationSource Format="TEX">$^{131}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mn>131</mn> </mmultiscripts> </math></EquationSource> </InlineEquation>I activity is essential for compliance monitoring and clinical safety. Methods A detection system integrating a NaI(Tl) crystal and a silicon photomultiplier array was developed to measure the <InlineEquation ID="IEq7"> <EquationSource Format="TEX">$^{131}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mn>131</mn> </mmultiscripts> </math></EquationSource> </InlineEquation>I concentrations via its 364.5 keV characteristic <InlineEquation ID="IEq8"> <EquationSource Format="TEX">$\gamma $</EquationSource> <EquationSource Format="MATHML"><math> <mi>γ</mi> </math></EquationSource> </InlineEquation>-ray emissions. The setup incorporates 5 cm oxygen-free copper and 5 cm lead shielding to mitigate external <InlineEquation ID="IEq9"> <EquationSource Format="TEX">$\gamma $</EquationSource> <EquationSource Format="MATHML"><math> <mi>γ</mi> </math></EquationSource> </InlineEquation>-ray interference. Sample analysis utilizes a 50 mL aliquot, with system sensitivity evaluated under varying measurement durations. Results Under optimized shielding conditions, the system achieved a minimum detectable activity of 8.0 Bq/L for <InlineEquation ID="IEq10"> <EquationSource Format="TEX">$^{131}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mn>131</mn> </mmultiscripts> </math></EquationSource> </InlineEquation>I within a 3-hour measurement period. Extending the acquisition time to 24 hours enhanced sensitivity to 2.8 Bq/L, surpassing the regulatory threshold requirement of 10 Bq/L. Conclusions The developed system demonstrates sufficient sensitivity and accuracy for monitoring <InlineEquation ID="IEq11"> <EquationSource Format="TEX">$^{131}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mn>131</mn> </mmultiscripts> </math></EquationSource> </InlineEquation>I in radioactive waste liquids, aligning with national emission standards. The time-dependent sensitivity improvement highlights its adaptability for both rapid screening and low-concentration quantification, thus validating its applicability in nuclear medicine waste management.

Developing a Bq/L level $^{131}\text {I}$ concentration in solution measurement system using NaI(Tl) crystal and SiPM

期刊论文
发表日期：

2025年4月4日

查看全文

D. Z. Zhang,
Q. Tang,
X. H. Liang,
C. Guo,
L. P. Xiang

摘要

Background

$^{131}$ $^{131}$ I is a critical radionuclide in nuclear medicine, particularly for thyroid disorder therapies. Chinese national standards mandate reducing $^{131}$ $^{131}$ I concentrations in radioactive waste liquid to below 10 Bq/L. To address this requirement, rapid and precise quantification of $^{131}$ $^{131}$ I activity is essential for compliance monitoring and clinical safety.

Methods

A detection system integrating a NaI(Tl) crystal and a silicon photomultiplier array was developed to measure the $^{131}$ $^{131}$ I concentrations via its 364.5 keV characteristic $\gamma $ $γ$ -ray emissions. The setup incorporates 5 cm oxygen-free copper and 5 cm lead shielding to mitigate external $\gamma $ $γ$ -ray interference. Sample analysis utilizes a 50 mL aliquot, with system sensitivity evaluated under varying measurement durations.

Results

Under optimized shielding conditions, the system achieved a minimum detectable activity of 8.0 Bq/L for $^{131}$ $^{131}$ I within a 3-hour measurement period. Extending the acquisition time to 24 hours enhanced sensitivity to 2.8 Bq/L, surpassing the regulatory threshold requirement of 10 Bq/L.

Conclusions

The developed system demonstrates sufficient sensitivity and accuracy for monitoring $^{131}$ $^{131}$ I in radioactive waste liquids, aligning with national emission standards. The time-dependent sensitivity improvement highlights its adaptability for both rapid screening and low-concentration quantification, thus validating its applicability in nuclear medicine waste management.

Developing a Bq/L level \(^{131}\text {I}\) concentration in solution measurement system using NaI(Tl) crystal and SiPM

摘要