In recurrent differentiated thyroid cancer patients, detectability in 124I PET is limited for lesions with low radioiodine uptake. We assess the improvements in lesion detectability and image quality between three generations of PET scanners with different detector technologies. The results are used to suggest an optimized protocol. Datasets of 10 patients with low increasing thyroglobulin or thyroglobulin antibody levels after total thyroidectomy and radioiodine therapies were included. PET data were acquired and reconstructed on a Biograph mCT PET/CT (whole-body, 4-min acquisition time per bed position; OSEM, OSEM-TOF, OSEM-TOF+PSF), a non-TOF Biograph mMR PET/MR (neck region, 4 min and 20 min; OSEM), and a new generation Biograph Vision PET/CT (whole-body, 4 min; OSEM, OSEM-TOF, OSEM-TOF+PSF). The 20-min image on the mMR was used as reference to calculate the detection efficacy in the neck region. Image quality was rated on a 5-point scale. All detected lesions were in the neck region. Detection efficacy was 8/9 (Vision OSEM-TOF and OSEM-TOF+PSF), 4/9 (Vision OSEM), 3/9 (mMR OSEM and mCT OSEM-TOF+PSF), and 2/9 (mCT OSEM and OSEM-TOF). Median image quality was 4 (Vision OSEM-TOF and OSEM-TOF+PSF), 3 (Vision OSEM, mCT OSEM-TOF+PSF, and mMR OSEM 20-min), 2 (mCT OSEM-TOF), 1.5 (mCT OSEM), and 1 (mMR OSEM 4 min). At a clinical standard acquisition time of 4 min per bed position, the new generation Biograph Vision using a TOF-based image reconstruction demonstrated the highest detectability and image quality and should, if available, be preferably used for imaging of low-uptake lesions. A prolonged acquisition time for the mostly affected neck region can be useful.

中文翻译：

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比较不同PET系统世代的病变检测功效和图像质量，以优化碘124 PET方案以治疗复发性甲状腺癌

在复发分化型甲状腺癌患者中，放射性碘摄入量低的病变在124I PET中的可检测性受到限制。我们评估了具有不同检测器技术的三代PET扫描仪在病变可检测性和图像质量方面的改进。结果用于建议优化的协议。包括10例甲状腺全球切除术和放射碘治疗后甲状腺球蛋白或甲状腺球蛋白抗体水平增低的患者的数据集。在Biograph mCT PET / CT（全身，每个床位采集4分钟的时间; OSEM，OSEM-TOF，OSEM-TOF + PSF），非TOF Biograph mMR PET / MR（颈部区域分别为4分钟和20分钟； OSEM）和新一代Biograph Vision PET / CT（全身4分钟； OSEM，OSEM-TOF，OSEM-TOF + PSF）。将mMR上的20分钟图像用作参考，以计算在颈部区域的检测功效。图像质量按5分制评分。所有检测到的病变均在颈部。检测效率为8/9（视觉OSEM-TOF和OSEM-TOF + PSF），4/9（视觉OSEM），3/9（mMR OSEM和mCT OSEM-TOF + PSF）和2/9（mCT OSEM和OSEM-TOF）。中位数图像质量为4（视觉OSEM-TOF和OSEM-TOF + PSF），3（视觉OSEM，mCT OSEM-TOF + PSF和mMR OSEM 20分钟），2（mCT OSEM-TOF），1.5（mCT OSEM ）和1（mMR OSEM 4分钟）。在每个床位4分钟的临床标准采集时间下，采用基于TOF的图像重建技术的新一代Biograph Vision表现出最高的可检测性和图像质量，并且如果可用，应优先用于低摄取病变的成像。