Development of sealed 22Na phantoms for PET system QA/QC: uniformity and stability evaluation
Development of sealed 22Na phantoms for PET system QA/QC: uniformity and stability evaluation
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用于 PET 系统 QA/QC 的密封 22Na 模型的开发：均匀性和稳定性评估
DOI：
10.1109/nss/mic42101.2019.9059761
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Taiga Yamaya
中科院分区：
文献类型：
--
作者：
Go Akamatsu;Eiji Yoshida;Takahiro Mikamoto;Takamasa Maeda;Hidekatsu Wakizaka;Hideaki Tashima;Yuichiro Wakitani;Mikio Matsumoto;Taiga Yamaya
Sodium-22 是一种放射性同位素，通常用作 PET 的校准点源。其2.6年的半衰期足够长，而其正电子射程与 18 F一样小。然而，22Na的使用仅限于点状形状。在这项工作中，在日本放射性同位素协会的帮助下，我们提出了更广泛的22Na密封体模。作为例子，我们开发了三种类型的 22Na 体模：5 厘米圆柱体、60 厘米柔性管和类似 Derenzo 的多杆体模。这些专为 PET 系统质量保证和质量控制 (QA/QC) 以及性能测量而设计。首先，在这项工作中，我们评估了这些体模放射性分布的均匀性和长期稳定性。这些体模在 446 天内由 Biograph mCT Flow PET/CT 扫描仪扫描了四次。通过视觉定性评估和基于感兴趣区域（ROI）的定量评估来评估放射性分布的均匀性。对于类似 Derenzo 的体模，我们还使用头盔式 PET 原型和 Inveon 小动物 PET 系统扫描了体模。此外，我们在 300 天内使用剂量校准器 (Atomlab 500) 测量了这些模型的放射性六次，并比较了测量的衰减曲线和理想的衰减曲线。结果，我们发现放射性分布的变异性低于圆柱体和管体模型的 5% 变异性。 Inveon PET 可视化了类似 Derenzo 模型的最小热棒（直径 1.6 毫米），并且放射性似乎均匀分布。所有模型的测量衰减曲线几乎遵循各自的理想衰减曲线。我们确认这些模型具有良好的均匀性和足够的稳定性，可用于 PET 系统评估。它们无需放射性溶液（例如 18F）即可评估和校准 PET 系统。
Sodium-22 is a radioisotope which is typically used as a calibration point source for PET. Its half-life of 2.6 years is suitably long enough while its positron range is as small as that of18F. However, the use of22Na has been limited to a point-like shape. In this work, with the help of the Japan Radioisotope Association, we proposed a wider variety of22Na sealed phantoms. As examples, we developed three types of22Na phantoms: a 5-cm cylinder, a 60-cm flexible tube and a Derenzo-like multi-rod phantom. These were designed for PET system quality assurance and quality control (QA/QC) and performance measurements. At first, in this work, we evaluated uniformity and long-term stability of radioactivity distributions of these phantoms. These phantoms were scanned by the Biograph mCT Flow PET/CT scanner four times during 446 days. The uniformity of radioactivity distributions was evaluated by visual qualitative assessment and region-of-interest (ROI)-based quantitative assessment. In the case of the Derenzo-like phantom, we additionally scanned the phantom using the helmet-type PET prototype and Inveon small-animal PET system. In addition, we measured the radioactivity of these phantoms using the dose calibrator (Atomlab 500) six times during 300 days and we compared the measured and ideal decay curves. As a result, we found the variability of radioactivity distributions was lower than the 5% variation for the cylinder and tube phantoms. The Inveon PET visualized the smallest hot rod (1.6 mm diameter) of the Derenzo-like phantom and the radioactivity seemed to be uniformly distributed. The measured decay curves of all phantoms almost followed their respective ideal decay curve. We confirmed these phantoms have good uniformity and enough stability for PET system evaluation. They enable to evaluate and calibrate PET systems without radioactive solutions (ex.18F).
影响因子：
3.5
作者：
Borghi, Giacomo;Tabacchini, Valerio;Schaart, Dennis R.
通讯作者：
Schaart, Dennis R.