Fukai Shohei, Daisaki Hiromitsu, Umeda Takuro, Shimada Naoki, Miyaji Noriaki, Ito Ryoma, Takiguchi Tomohiro, Terauchi Takashi
Department of Nuclear Medicine, The Cancer Institute Hospital of Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan.
Graduate School of Radiological Technology, Gunma Prefectural College of Health Sciences, 323-1 Kamioki-machi, Maebashi, Gunma, 371-0052, Japan.
Ann Nucl Med. 2022 Jun;36(6):586-595. doi: 10.1007/s12149-022-01746-4. Epub 2022 May 11.
The first edition of guidelines for standardization of bone single photon emission computed tomography (SPECT) imaging was published in 2017, and the optimization and standardization are widely promoted. To the purpose, clarification of the factors related to image quality and quantitative values and their influence are required. The present study aimed to clarify and optimize the influence of patient body habitus on image quality and quantitative values in bone SPECT/CT.
National Electrical Manufacturers Association body phantom (S-size) and custom-made large body phantoms (M-size and L-size) that simulate the abdomens of Japanese patients weighing 60, 80, and 100 kg, were used. Each phantom was filled with Tc-solutions of 108 and 18 kBq/mL for the hot spheres and background, respectively. Dynamic SPECT acquisition was performed for 6000 s (150 s /rotation × 40 rotation). The data were divided into six projection data and reconstructed each acquisition time (150, 300, 450, 600, 750, 900 s, and single projection 6000 s). Image quality was evaluated for contrast (Q), background noise (N), contrast-to-noise ratio (CNR), maximum standardized uptake value (SUV), and visual assessment for a 17 mm hot sphere.
Image quality in the 300 s acquisition showed that values of Q, CNR, and SUV decreased (-16.7%, -11.8%, and -11.3%) for M-size and (-28.2%, -30.1%, and -21.7%) for L-size compared with S-size, respectively. No significant difference was observed in N values. M-size and L-size required 1.2 and 2.3 times longer acquisition, to achieve same CNR as S-size. In visual assessment, 17 mm hot sphere could not be detected only in the L-size. When the Japanese bone SPECT guidelines criteria were applied in 600 s, the sphere could be detected between all phantoms.
Patient body habitus significantly affects image quality and decreases the quantitative value in bone SPECT/CT. For the optimization, extend acquisition time according to the patient body habitus is effective for image quality. And for the standardization, it is important to achieve imaging conditions that meet the Japanese bone SPECT guidelines criteria to ensure adequate detectability.
骨单光子发射计算机断层扫描（SPECT）成像标准化指南第一版于2017年发布，优化和标准化工作得到广泛推广。为此，需要明确与图像质量和定量值相关的因素及其影响。本研究旨在阐明并优化患者体型对骨SPECT/CT图像质量和定量值的影响。
使用美国国家电气制造商协会体模（S尺寸）和定制的大体模（M尺寸和L尺寸），分别模拟体重为60、80和100千克的日本患者的腹部。每个体模分别填充108和18 kBq/mL的锝溶液用于热球和背景。进行6000秒（150秒/旋转×40次旋转）的动态SPECT采集。数据被分为六个投影数据，并对每个采集时间（150、300、450、600、750、900秒以及单次投影6000秒）进行重建。对图像质量进行对比度（Q）、背景噪声（N）、对比度噪声比（CNR）、最大标准化摄取值（SUV）评估，并对17毫米热球进行视觉评估。
300秒采集时的图像质量显示，与S尺寸相比，M尺寸的Q、CNR和SUV值分别下降了（-16.7%、-11.8%和-11.3%），L尺寸分别下降了（-28.2%、-30.1%和-21.7%）。N值未观察到显著差异。M尺寸和L尺寸需要的采集时间分别是S尺寸的1.2倍和2.3倍，才能达到相同的CNR。在视觉评估中，仅在L尺寸中无法检测到17毫米热球。当在600秒应用日本骨SPECT指南标准时，所有体模之间均可检测到热球。
患者体型对骨SPECT/CT的图像质量有显著影响，并降低定量值。为了优化，根据患者体型延长采集时间对图像质量有效。为了标准化，重要的是实现符合日本骨SPECT指南标准的成像条件，以确保足够的可检测性。
