Charge-coupled device detector: performance considerations and potential for small-field mammographic imaging applications.
Charge-coupled device detector: performance considerations and potential for small-field mammographic imaging applications.
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DOI：
10.1118/1.596819
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发表时间：
1992-07
期刊：
影响因子：
3.8
通讯作者：
A. Karellas;L. J. Harris;Hong Liu;Hong Liu;Michael A. Davis;Carl J. D'Orsi
中科院分区：
文献类型：
--
作者：
A. Karellas;L. J. Harris;Hong Liu;Hong Liu;Michael A. Davis;Carl J. D'Orsi
评价了电荷耦合器件（CCD）图像探测器的物理特性，以及其作为小视野乳腺摄影应用（如术前针定位）的数字成像设备的潜力。检测系统基于在1024 x 1024模式下操作的2048 x 2048像素CCD。CCD通过透镜光学耦合到增感屏，而没有中间增强。用液氮冷却CCD，可将热噪声抑制到0.15电子像素-1s-1。噪声的主要来源归因于在以50，000像素s-1执行的读出过程期间的片上放大器。测量的读出噪声水平为每像素15个电子。该CCD原型探测器的低噪声特性在模拟乳腺X射线摄影的条件下产生了令人鼓舞的结果，对于每个检测到的X射线，信号水平接近每个像素一个电子。根据从标准乳房X线摄影体模测量的入射照射，乳房的平均腺体剂量为1.52 mGy（152 mrad）。该系统的最终空间分辨率约为8个周期/mm，但当在1024 × 1024成像模式下操作时，其限于约5个周期/mm。系统的其他物理特性，如光耦合效率，曝光响应，和信噪比进行了评价。这项研究的结果表明，使用科学级CCD允许非常好的低对比度的歧视和中等的空间分辨率的条件下模拟乳腺X线摄影，但目前的原型是有限的9 × 9平方厘米的视野。（250字处删节）
The physical characteristics of a charge-coupled device (CCD) image detector were evaluated, as well as its potential as a digital imaging device for small field mammographic applications such as preoperative needle localization. The detection system is based on a 2048 x 2048 pixel CCD operated in 1024 x 1024 mode. The CCD was optically coupled to an intensifying screen via a lens, without intermediate intensification. The thermal noise was suppressed to 0.15 electrons pixel-1s-1 by cooling the CCD with liquid nitrogen. The dominant source of noise was attributed to the on-chip amplifier during the readout process that was performed at 50,000 pixels s-1. The measured readout noise level was 15 electrons per pixel. The low-noise characteristics of this CCD prototype detector produced encouraging results under conditions simulating mammography, with a signal level close to one electron per pixel for each detected x ray. The mean glandular dose to the breast, based on the entrance exposure measured from a standard mammographic phantom would be 1.52 mGy (152 mrad). The ultimate spatial resolution of the system was approximately 8 cycles/mm but it was limited to about 5 cycles/mm when operated in the 1024 x 1024 imaging mode. Other physical characteristics of the system such as optical coupling efficiency, exposure response, and signal-to-noise ratio were evaluated. The results of this study suggest that the use of a scientific-grade CCD allows for very good low-contrast discrimination and moderate spatial resolution under conditions simulating mammography, but the current prototype is limited to a 9 x 9-cm2 field of view.(ABSTRACT TRUNCATED AT 250 WORDS)