The Bayesian penalized likelihood (BPL) algorithm Q.Clear (GE Healthcare) allows fully convergent iterative reconstruction that results in better image quality and quantitative accuracy, while limiting image noise. The present study aimed to optimize BPL reconstruction parameters for 18F-NaF PET/CT images and to determine the feasibility of 18F-NaF PET/CT image acquisition over shorter durations in clinical practice. A custom-designed thoracic spine phantom consisting of several inserts, soft tissue, normal spine, and metastatic bone tumor, was scanned using a Discovery MI PET/CT scanner (GE Healthcare). The phantom allows optional adjustment of activity distribution, tumor size, and attenuation. We reconstructed PET images using OSEM + PSF + TOF (2 iterations, 17 subsets, and a 4-mm Gaussian filter), BPL + TOF (β = 200 to 700), and scan durations of 30–120 s. Signal-to-noise ratios (SNR), contrast, and coefficients of variance (CV) as image quality indicators were calculated, whereas the quantitative measures were recovery coefficients (RC) and RC linearity over a range of activity. We retrospectively analyzed images from five persons without bone metastases (male, n = 1; female, n = 4), then standardized uptake values (SUV), CV, and SNR at the 4th, 5th, and 6th thoracic vertebra were calculated in BPL + TOF (β = 400) images. The optimal reconstruction parameter of the BPL was β = 400 when images were acquired at 120 s/bed. At 90 s/bed, the BPL with a β value of 400 yielded 24% and 18% higher SNR and contrast, respectively, than OSEM (2 iterations; 120 s acquisitions). The BPL was superior to OSEM in terms of RC and the RC linearity over a range of activity, regardless of scan duration. The SUVmax were lower in BPL, than in OSEM. The CV and vertebral SNR in BPL were superior to those in OSEM. The optimal reconstruction parameters of 18F-NaF PET/CT images acquired over different durations were determined. The BPL can reduce PET acquisition to 90 s/bed in 18F-NaF PET/CT imaging. Our results suggest that BPL (β = 400) on SiPM-based TOF PET/CT scanner maintained high image quality and quantitative accuracy even for shorter acquisition durations.

中文翻译：

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使用定制设计的幻像对较短时间内获取的18F-NaF骨PET / CT图像的贝叶斯罚分似然算法（Q.Clear）的优化。

贝叶斯惩罚似然（BPL）算法Q.Clear（GE Healthcare）允许完全收敛的迭代重建，从而在限制图像噪声的同时提高了图像质量和定量精度。本研究旨在优化18F-NaF PET / CT图像的BPL重建参数，并确定在临床实践中以较短的时间获取18F-NaF PET / CT图像的可行性。使用Discovery MI PET / CT扫描仪（GE Healthcare）扫描了定制设计的由多个插入物，软组织，正常脊柱和转移性骨肿瘤组成的胸椎体模。体模允许对活动分布，肿瘤大小和衰减进行可选调整。我们使用OSEM + PSF + TOF（2次迭代，17个子集和4mm高斯滤镜），BPL + TOF（β= 200至700）重建了PET图像，扫描时间为30–120 s。计算信噪比（SNR），对比度和方差系数（CV）作为图像质量指标，而定量方法是在一系列活动范围内恢复系数（RC）和RC线性。我们回顾性分析了五个没有骨转移的人（男性，n = 1；女性，n = 4）的图像，然后在BPL中计算了第4、5和6胸椎的标准化摄取值（SUV），CV和SNR。 + TOF（β= 400）图像。当以120 s /床的速度采集图像时，BPL的最佳重建参数为β= 400。在90 s / bed时，β值为400的BPL的信噪比和对比度比OSEM分别高24％和18％（2次迭代； 120 s采集）。在一系列活动范围内，BPL在RC和RC线性方面均优于OSEM，无论扫描持续时间如何。BPL的SUVmax低于OSEM。BPL的CV和椎骨SNR优于OSEM。确定了在不同持续时间内获取的18F-NaF PET / CT图像的最佳重建参数。在18F-NaF PET / CT成像中，BPL可以将PET采集降低至90 s /床。我们的结果表明，即使对于较短的采集时间，基于SiPM的TOF PET / CT扫描仪上的BPL（β= 400）仍可保持较高的图像质量和定量精度。