Kanzaki Takao, Takahashi Yasuyuki, Higuchi Tetsuya, Zhang Xieyi, Mogi Nao, Suto Takayuki, Tsushima Yoshito
Department of Radiology, Gunma University Hospital, Gunma, Japan
Department of Nuclear Medicine Technology, Hirosaki University Graduate School of Health Sciences, Aomori, Japan.
J Nucl Med Technol. 2020 Dec;48(4):326-330. doi: 10.2967/jnmt.120.249680. Epub 2020 Sep 4.
The number of patients with the extremely rare disease gastroenteropancreatic (GEP) neuroendocrine tumor (NET) has increased rapidly in recent years. In-pentetreotide SPECT in somatostatin receptor scintigraphy has been used for the assessment of GEP NET patients. To diagnose GEP NET, appropriate selection of image correction parameters is critical. Correction methods may improve the In-pentetreotide SPECT image quality, but there is currently no standard technique. The purpose of this study was to determine the optimal correction parameter settings for In-pentetreotide SPECT. A phantom study produced images with a tumor-to-background ratio of as high as 16:1. A triple energy window was used for scatter correction (SC), and attenuation correction (AC) was CT-based. Correlation analysis was performed in 4 groups: no correction (NC), SC, AC, and combined SC with AC (CC). The In-pentetreotide SPECT results for 20 randomly selected patients (13 men and 7 women; age range, 37-81 y) with confirmed GEP NET were analyzed using data collected 4 h after injection of 111 MBq of In-pentetreotide. Emission data were reconstructed using ordered-subset expectation maximization (OSEM) with different settings. Different combinations of the correction parameters were used to analyze the contrast-to-noise ratios (CNRs) obtained with the phantom. In the clinical study, 20 GEP NET patients were used to evaluate the GEP NET lesion CNR by 4 different image correction methods obtained from In-pentetreotide SPECT images: NC, SC, AC, and CC. NC was used as a reference method. The phantom study revealed that the optimal energy window in the photopeak for somatostatin receptor scintigraphy was 171 keV ± 10% and 245 keV ± 7.5%, and the optimal OSEM reconstruction conditions were 8 subsets and 6 iterations. Among the OSEM collection conditions, CC produced a significantly higher CNR than NC or SC ( < 0.05). In the clinical study, CC was found to increase the CNR ( < 0.05). CC improves the correction in In-pentetreotide SPECT studies, compared with NC, providing better contrast and sharper outlines of lesions and organs.
近年来，极罕见的胃肠胰（GEP）神经内分泌肿瘤（NET）患者数量迅速增加。生长抑素受体闪烁显像中的铟-喷曲肽单光子发射计算机断层扫描（SPECT）已用于评估GEP NET患者。为诊断GEP NET，正确选择图像校正参数至关重要。校正方法可能会改善铟-喷曲肽SPECT图像质量，但目前尚无标准技术。本研究的目的是确定铟-喷曲肽SPECT的最佳校正参数设置。一项体模研究生成了肿瘤与背景比值高达16:1的图像。采用三能量窗进行散射校正（SC），衰减校正（AC）基于CT。在四组中进行相关性分析：无校正（NC）、SC、AC以及SC与AC联合（CC）。对20例经确诊的GEP NET患者（13例男性和7例女性；年龄范围37 - 81岁）进行铟-喷曲肽SPECT检查，在注射111 MBq铟-喷曲肽4小时后收集数据并进行分析。发射数据使用不同设置的有序子集期望最大化（OSEM）进行重建。使用校正参数的不同组合分析体模获得的对比噪声比（CNR）。在临床研究中，20例GEP NET患者用于通过从铟-喷曲肽SPECT图像获得的4种不同图像校正方法评估GEP NET病变的CNR：NC、SC、AC和CC。NC用作参考方法。体模研究表明，生长抑素受体闪烁显像光电峰的最佳能量窗为171 keV±10%和245 keV±7.5%，最佳OSEM重建条件为8个子集和6次迭代。在OSEM采集条件中，CC产生的CNR显著高于NC或SC（<0.05）。在临床研究中，发现CC可提高CNR（<0.05）。与NC相比，CC改善了铟-喷曲肽SPECT研究中的校正，提供了更好的病变和器官对比度以及更清晰的轮廓。
