Using phantoms and clinical studies in prone hanging breast imaging, we assessed the image quality of a commercially available dedicated breast PET (dbPET) at the detector’s edge, where mammary glands near the chest wall are located. These are compared to supine PET/CT breast images of the same clinical subjects. A breast phantom with four spheres (16-, 10-, 7.5-, and 5-mm diameter) was filled with 18F-fluorodeoxyglucose solution (sphere-to-background activity concentration ratio, 8:1). The spheres occupied five different positions from the top edge to the centre of the detector and were scanned for 5 min in each position. Reconstructed images were visually evaluated, and the contrast-to-noise ratio (CNR), contrast recovery coefficient (CRC) for all spheres, and coefficient of variation of the background (CVB) were calculated. Subsequently, clinical images obtained with standard supine PET/CT and prone dbPET were retrospectively analysed. Tumour-to-background ratios (TBRs) between breast cancer near the chest wall (close to the detector’s edge; peripheral group) and at other locations (non-peripheral group) were compared. The TBR of each lesion was compared between dbPET and PET/CT. Closer to the detector’s edge, the CNR and CRC of all spheres decreased while the CVB increased in the phantom study. The disadvantages of this placement were visually confirmed. Regarding clinical images, TBR of dbPET was significantly higher than that of PET/CT in both the peripheral (12.38 ± 6.41 vs 6.73 ± 3.5, p = 0.0006) and non-peripheral (12.44 ± 5.94 vs 7.71 ± 7.1, p = 0.0183) groups. There was no significant difference in TBR of dbPET between the peripheral and non-peripheral groups. The phantom study revealed poorer image quality at < 2-cm distance from the detector’s edge than at other more central parts. In clinical studies, however, the visibility of breast lesions with dbPET was the same regardless of the lesion position, and it was higher than that in PET/CT. dbPET has a great potential for detecting breast lesions near the chest wall if they are at least 2 cm from the edge of the FOV, even in young women with small breasts.

中文翻译：

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专用乳房正电子发射断层扫描仪检测器边缘的图像质量评估

使用俯卧悬挂式乳房成像中的人体模型和临床研究，我们在检测器边缘（胸壁附近的乳腺所在的位置）评估了市售专用乳房PET（dbPET）的图像质量。将这些与相同临床受试者的仰卧PET / CT乳房图像进行比较。用18F-氟脱氧葡萄糖溶液（球与背景活性的浓度比为8：1）填充具有四个球体（直径分别为16、10、7.5和5毫米）的乳房模型。从检测器的顶部边缘到中心，这些球占据了五个不同的位置，并在每个位置扫描了5分钟。目视评估重建的图像，并计算所有球体的对比噪声比（CNR），对比恢复系数（CRC）和背景变化系数（CVB）。后来，回顾性分析标准仰卧位PET / CT和俯卧dbPET获得的临床图像。比较了胸壁附近（靠近检测器边缘；外围组）和其他位置（非外围组）的乳腺癌之间的肿瘤背景比（TBR）。在dbPET和PET / CT之间比较每个病变的TBR。在幻像研究中，靠近探测器边缘的所有球体的CNR和CRC降低，而CVB升高。视觉上确认了该放置的缺点。关于临床图像，在外周（12.38±6.41 vs 6.73±3.5，p = 0.0006）和非外周（db.12.44±5.94 vs 7.71±7.1，p = 0.0183）中，dbPET的TBR显着高于PET / CT。组。外周血和非外周血的dbPET的TBR没有显着差异。幻像研究表明，与探测器边缘的距离小于2 cm时，图像质量较其他中央部分差。但是，在临床研究中，无论病变位置如何，dbPET对乳腺病变的可见性均相同，并且高于PET / CT。如果dbPET距FOV边缘至少2 cm，则即使在乳房较小的年轻女性中，dbPET也具有检测胸壁附近乳房病变的巨大潜力。