Pautasso Juan J, Van Speybroeck Camille D E, Michielsen Koen, Sechopoulos Ioannis
Department of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands.
Dutch Expert Centre for Screening (LRCB), Nijmegen, The Netherlands.
Med Phys. 2025 Apr;52(4):2191-2200. doi: 10.1002/mp.17623. Epub 2025 Jan 21.
Dedicated breast computed tomography (bCT) systems offer detailed imaging for breast cancer diagnosis and treatment. As new bCT generations are developed, it is important to evaluate their imaging performance and dose efficiency to understand differences over previous models.
To characterize the imaging performance and dose efficiency of a second-generation (GEN2) bCT system and compare them to those of a first-generation (GEN1) system.
The imaging performance was evaluated through key metrics: modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) in the projection domain. In the image domain, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), and the visibility of calcifications were analyzed using a quality control (QC) phantom with masses and calcification clusters. Air kerma and tube output were measured and mean glandular dose (MGD) estimated for different phantom sizes for dosimetric characterization of the acquisition protocols set by the automatic exposure control (AEC).
GEN2 outperformed GEN1 at higher spatial frequencies, with 57% of the MTF observed at 1 cycles/mm compared to 43% for GEN1. For a 2 mm diameter mass, GEN2 showed 60% higher CNR and 63% higher SNR. However, for larger masses, GEN1 outperformed GEN2, with CNR and SNR values higher by 12% to 44% and 14% to 43%, respectively. GEN2 also achieves higher DQE across the frequency spectrum, with 45% at 1 cycle/mm, compared to GEN1's 20%. Regarding calcifications in the QC phantom, the 320 µm calcifications resulted in distinct full-width-at-half-maxima (FWHM ± SD), with 897 ± 58 µm for GEN1 and 811 ± 127 µm for GEN2, with a p-value of 0.19. For 290 µm calcifications, GEN1's FWHM was 866 ± 129 µm, while GEN2's was narrower at 665 ± 57 µm, with a p-value of 0.01. The tube output was higher for GEN1 (45.2 mGy/mAs) compared to GEN2 (31.5 mGy/mAs). Additionally, GEN2 resulted in 8% lower MGD values compared to GEN1.
While GEN1 offers better CNR and SNR for larger masses, GEN2 provides superior resolution for calcifications, better MTF, improved DQE, and lower MGD at AEC-determined settings.
专用乳腺计算机断层扫描（bCT）系统可为乳腺癌的诊断和治疗提供详细成像。随着新一代bCT的开发，评估其成像性能和剂量效率以了解与先前型号的差异非常重要。
表征第二代（GEN2）bCT系统的成像性能和剂量效率，并将其与第一代（GEN1）系统进行比较。
通过关键指标评估成像性能：投影域中的调制传递函数（MTF）、噪声功率谱（NPS）和量子检测效率（DQE）。在图像域中，使用带有肿块和钙化簇的质量控制（QC）体模分析对比度噪声比（CNR）、信噪比（SNR）和钙化的可见性。测量空气比释动能和管输出，并估计不同体模尺寸的平均腺体剂量（MGD），以对自动曝光控制（AEC）设置的采集协议进行剂量学表征。
在较高空间频率下，GEN2的性能优于GEN1，在1周期/毫米处观察到的MTF为57%，而GEN1为43%。对于直径2毫米的肿块，GEN2的CNR高60%，SNR高63%。然而，对于较大的肿块，GEN1的性能优于GEN2，CNR和SNR值分别高12%至44%和14%至43%。GEN2在整个频谱上也实现了更高的DQE，在1周期/毫米处为45%，而GEN1为20%。关于QC体模中的钙化，320微米的钙化产生了明显的半高宽（FWHM±标准差），GEN1为897±58微米，GEN2为811±127微米，p值为0.19。对于290微米的钙化，GEN1的FWHM为866±129微米，而GEN2的更窄，为665±57微米，p值为0.01。GEN1的管输出（45.2毫戈瑞/毫安秒）高于GEN2（31.5毫戈瑞/毫安秒）。此外，与GEN1相比，GEN2的MGD值低8%。
虽然GEN1对于较大肿块提供了更好的CNR和SNR，但GEN2在AEC确定的设置下为钙化提供了更高的分辨率、更好的MTF、更高的DQE和更低的MGD。
