Determination of X- and gamma-ray emission intensities in the decay of 123I and 177Lu

IF 1.8 3区工程技术 Q3 CHEMISTRY, INORGANIC & NUCLEAR

Applied Radiation and Isotopes Pub Date : 2025-09-25 DOI:10.1016/j.apradiso.2025.112212

Marie-Christine Lépy, Bruno Boyer, Sylvie Pierre, Ablaihan Utepov, Christophe Bobin, Lucille Chambon

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引用次数: 0

Abstract

I-123 (T_1/2 = 13.2234(37) h) decays by electron capture mainly via the 159 keV level of Te-123 (97 %) and is characterized by strong gamma-ray emission at 159.0 keV, as well as intense tellurium K X-rays and numerous low-intensity gamma-rays with energies up to 1 MeV. Lu-177 (T_1/2 = 6.647(4) d) decays by beta-emission to the ground state and to three excited levels of Hf-177. Its main photon emissions are the hafnium K X-rays and gamma-rays at 112.9 keV and 208.4 keV; four minor gamma-rays are also emitted. The measurement of photon emission intensities was performed using four N-type high-purity germanium detectors accurately calibrated using standard point sources, in complementary energy ranges. For each radionuclide, several point sources were prepared and checked for homogeneity. For ¹²³I, the study was carried out in two stages.

Here, only relative photon emission intensities for about 30 energies could be measured, with relative combined standard uncertainties of about 1 % for the largest ones and of about 2 %–2.5 % for ten minor lines. For ¹⁷⁷Lu, the sources were measured in the calibration conditions (at the reference distance) to derive absolute photon emission intensities, thanks to accurate sources activity, obtained by a primary method (4π β-γ coincidences using a liquid scintillation detector in the β channel). The six absolute gamma-ray emission intensities are obtained with relative combined standard uncertainties between 0.7 % and 1.9 %. The whole measurement procedure is presented and the resulting photon emission intensities are compared with previously published values.

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123I和177Lu衰变中X射线和伽马射线发射强度的测定。

I-123 （T1/2 = 13.2234(37) h）主要通过Te-123（97%）的159 keV能级的电子捕获衰变，其特征是159.0 keV的强伽马射线发射，以及强烈的碲K x射线和许多能量高达1 MeV的低强度伽马射线。Lu-177 （T1/2 = 6.647(4) d）通过β -发射衰变到基态和Hf-177的三个激发态。它的主要光子发射是112.9 keV和208.4 keV的铪K x射线和伽马射线；四种次要的伽马射线也被释放出来。光子发射强度的测量使用4个n型高纯度锗探测器，使用标准点源精确校准，在互补能量范围内。对于每种放射性核素，制备了几个点源并检查了均匀性。对于123I，研究分两个阶段进行。在这里，只能测量大约30个能量的相对光子发射强度，最大的相对组合标准不确定度约为1%，10个次要线的相对组合标准不确定度约为2% - 2.5%。对于177Lu，我们在校准条件下（参考距离下）测量了光源，得到了绝对光子发射强度，这要归功于精确的光源活度，这是通过一种主要方法（在β通道中使用液体闪烁探测器的4π β-γ巧合）获得的。在相对综合标准不确定度为0.7% ~ 1.9%的情况下，得到了6种绝对伽马射线发射强度。介绍了整个测量过程，并将所得的光子发射强度与先前公布的值进行了比较。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Applied Radiation and Isotopes 工程技术-核科学技术

CiteScore

3.00

自引率

12.50%

发文量

406

审稿时长

13.5 months

期刊介绍： Applied Radiation and Isotopes provides a high quality medium for the publication of substantial, original and scientific and technological papers on the development and peaceful application of nuclear, radiation and radionuclide techniques in chemistry, physics, biochemistry, biology, medicine, security, engineering and in the earth, planetary and environmental sciences, all including dosimetry. Nuclear techniques are defined in the broadest sense and both experimental and theoretical papers are welcome. They include the development and use of α- and β-particles, X-rays and γ-rays, neutrons and other nuclear particles and radiations from all sources, including radionuclides, synchrotron sources, cyclotrons and reactors and from the natural environment. The journal aims to publish papers with significance to an international audience, containing substantial novelty and scientific impact. The Editors reserve the rights to reject, with or without external review, papers that do not meet these criteria. Papers dealing with radiation processing, i.e., where radiation is used to bring about a biological, chemical or physical change in a material, should be directed to our sister journal Radiation Physics and Chemistry.