García Hernández Trinitat, Vicedo González Aurora, Ferrer Rebolleda Jose, Sánchez Jurado Raúl, Roselló Ferrando Joan, Brualla González Luis, Granero Cabañero Domingo, Del Puig Cozar Santiago Maria
Department of Medical Physics, ERESA, Hospital General Universitario, Valencia 46014, Spain.
Department of Nuclear Medicine, ERESA, Hospital General Universitario, Valencia 46014, Spain.
Med Phys. 2016 May;43(5):2261. doi: 10.1118/1.4945271.
Early stage breast cancers may not be visible on a whole-body PET scan. To overcome whole-body PET limitations, several dedicated breast positron emission tomography (DbPET) systems have emerged nowadays aiming to improve spatial resolution. In this work the authors evaluate the performance of a high resolution dedicated breast PET scanner (Mammi-PET, Oncovision).
Global status, uniformity, sensitivity, energy, and spatial resolution were measured. Spheres of different sizes (2.5, 4, 5, and 6 mm diameter) and various 18 fluorodeoxyglucose ((18)F-FDG) activity concentrations were randomly inserted in a gelatine breast phantom developed at our institution. Several lesion-to-background ratios (LBR) were simulated, 5:1, 10:1, 20:1, 30:1, and 50:1. Images were reconstructed using different voxel sizes. The ability of experienced reporters to detect spheres was tested as a function of acquisition time, LBR, sphere size, and matrix reconstruction voxel size. For comparison, phantoms were scanned in the DbPET camera and in a whole body PET (WB-PET). Two patients who just underwent WB-PET/CT exams were imaged with the DbPET system and the images were compared.
The measured absolute peak sensitivity was 2.0%. The energy resolution was 24.0% ± 1%. The integral and differential uniformity were 10% and 6% in the total field of view (FOV) and 9% and 5% in the central FOV, respectively. The measured spatial resolution was 2.0, 1.9, and 1.7 mm in the radial, tangential, and axial directions. The system exhibited very good detectability for spheres ≥4 mm and LBR ≥10 with a sphere detection of 100% when acquisition time was set >3 min/bed. For LBR = 5 and acquisition time of 7 min the detectability was 100% for spheres of 6 mm and 75% for spheres of 5, 4, and 2.5 mm. Lesion WB-PET detectability was only comparable to the DbPET camera for lesion sizes ≥5 mm when acquisition time was >3 min and LBR > 10.
The DbPET has a good performance for its clinical use and shows an improved resolution and lesion detectability of small lesions compared to WB-PET.
早期乳腺癌在全身PET扫描中可能无法显示。为克服全身PET的局限性，目前已出现了几种专用乳腺正电子发射断层扫描（DbPET）系统，旨在提高空间分辨率。在本研究中，作者评估了一种高分辨率专用乳腺PET扫描仪（Mammi-PET，Oncovision）的性能。
测量了整体性能、均匀性、灵敏度、能量和空间分辨率。将不同大小（直径2.5、4、5和6 mm）以及不同18氟脱氧葡萄糖（(18)F-FDG）活度浓度的球体随机插入到我们机构研制的明胶乳腺模型中。模拟了几种病变与背景比值（LBR），即5:1、10:1、20:1、30:1和50:1。使用不同的体素大小重建图像。测试了经验丰富的报告者检测球体的能力，该能力是采集时间、LBR、球体大小和矩阵重建体素大小的函数。为作比较，在DbPET相机和全身PET（WB-PET）中对模型进行扫描。对两名刚接受WB-PET/CT检查的患者使用DbPET系统进行成像，并对图像进行比较。
测得的绝对峰值灵敏度为2.0%。能量分辨率为24.0%±1%。在整个视野（FOV）中，积分均匀性和微分均匀性分别为10%和6%，在中心FOV中分别为9%和5%。在径向、切向和轴向上测得的空间分辨率分别为2.0、1.9和1.7 mm。当采集时间设置为>3分钟/床位时，该系统对直径≥4 mm且LBR≥10的球体具有非常好的可检测性，球体检测率为100%。对于LBR = 5且采集时间为7分钟的情况，6 mm球体的可检测率为100%，5、4和2.5 mm球体的可检测率为75%。当采集时间>3分钟且LBR>10时，对于大小≥5 mm的病变，WB-PET的病变可检测性仅与DbPET相机相当。
DbPET在临床应用中具有良好的性能，与WB-PET相比，其对小病变的分辨率和病变可检测性有所提高。
