Effect of radioactivity outside the field of view on image quality of dedicated breast positron emission tomography: preliminary phantom and clinical studies
Effect of radioactivity outside the field of view on image quality of dedicated breast positron emission tomography: preliminary phantom and clinical studies
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DOI：
10.1007/s12149-022-01789-7
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发表时间：
2022-10-08
影响因子：
2.6
通讯作者：
Onishi, Hiroshi
中科院分区：
文献类型：
--
作者：
Satoh, Yoko;Imai, Masamichi;Onishi, Hiroshi
目的半定量正电子发射断层扫描（PET）值，如最大标准化摄取值（SUVmax），被广泛用于识别恶性病变和评估对治疗的反应。环形专用乳房正电子发射断层扫描（dbPET）的图像质量已经被认为是降低越接近探测器的边缘。本研究旨在探讨探测器视场外放射性（RI）对环形dbPET成像质量的影响。方法采用3D打印机制备含有左心肌的乳腺假体，在假体中填充不同RI浓度比（rcr）的f -18-氟脱氧葡萄糖（FDG）溶液，以顶点边缘精确定位于dbPET扫描仪视场边缘进行扫描。对影像质量进行了目测和定量评价。在幻影研究之后，定量评估74名女性的临床dbPET图像上的左右乳房差异（左乳房与右乳房摄取比（LUR））。分析这些参数、临床指标与PET/ CT左心肌FDG摄取的关系。结果幻像研究显示，心肌RCR越高，越靠近幻像的上边缘，dbPET图像的像素值越高。在一项临床研究中，LUR与全身PET/CT成像的心肌SUVmax （r = 0.96, p < 0.0001）和代谢心肌体积（r = 0.63, p = 0.001）显著相关。LUR与年龄（r = 0.05, p = 0.6865）、体重指数（r = 0.03, p = 0.8178）、左心尖至胸壁距离（r = 0.16, p = 0.1667）无显著相关性。结论心肌FDG摄取影响左乳，尤其是胸壁附近的dbPET图像。此外，在使用dbPET对乳腺癌进行定量评估时，必须考虑视场外（如心肌）RI的影响。
Objective Semi-quantitative positron emission tomography (PET) values, such as the maximum standardized uptake value (SUVmax), are widely used to identify malignant lesions and evaluate the response to treatment. The image quality of ring-shaped dedicated breast positron emission tomography (dbPET) has been known to decrease the closer it is to the detector's edge. This study aimed to investigate the effect of radioactivity (RI) outside the detector field of view (FOV) on the image quality of the ring-shaped dbPET. Methods A breast phantom containing the left myocardium, which was prepared using a 3D printer, filled with F-18-fluorodeoxyglucose (FDG) solution with various RI concentration ratios (RCRs) of myocardium to background and scanned with the edge of an apex positioned exactly in line with the edge of the FOV of the dbPET scanner. The phantom image quality was visually and quantitatively evaluated. Following the phantom study, left-right breast differences (the left breast uptake ratio to the right breast (LUR)) on clinical dbPET images of 74 women were quantitatively evaluated. The relationships between these parameters, clinical indices, and FDG uptake in the left myocardium on PET/computed tomography (CT) images were analyzed. Results The phantom study showed that the higher the RCR of the myocardium and the closer it is to the top edge of the phantom, the higher is the pixel value of the dbPET images. In a clinical study, LUR was significantly correlated with myocardial SUVmax (r = 0.96, p < 0.0001) and metabolic myocardial volume (r = 0.63, p = 0.001) for whole-body PET/CT imaging. Although no significant correlations were found between LUR and age (r = 0.05, p = 0.6865), body mass index (r = 0.03, p = 0.8178), or distance between the left myocardial apex and chest wall (r = 0.16, p = 0.1667). Conclusions FDG uptake in the myocardium affected dbPET images of the left breast, especially near the chest wall. Further, the effect of RI outside the FOV, such as in the myocardium, must be considered in the quantitative evaluation of breast cancer using dbPET.