A Development of a high sensitivity cephalometric radiography using a photon-counting X-ray sensor.

Cd/Te x射线传感器是一种超高灵敏度的x射线探测器，用于头颅影像学的发展。一个Cd/Te晶体、一个高速脉冲放大器、一个比较器和一个16位计数器是x射线探测器的基本组成部分。首先，Cd/Te晶体捕获x射线光子并产生电压与x射线光子能量成比例的电脉冲信号。其次，高速脉冲放大器放大电脉冲。第三，用比较器截断电信号中的噪声成分。第四，由比较器对纯化电信号的脉冲数进行计数。这样，一个像素值被测量出来。制作了尺寸约为2x130 mm的二维传感器。该传感器安装在特制的牙科全景x光机上AZ3000^<TM>。这台机器可以进行扫描，然后将头颅x线摄影作为扫描x线摄影技术。该系统的灵敏度几乎是传统屏幕胶片系统的20倍。制作了x线影像观测站，用于观察头颅影像。该查看系统基于DICOM3.0标准，具有一个基于超文本的用户界面。

Cd/Te X-ray sensor was used as a super high sensitive X-ray detector for the development of cephalometric radiography. A Cd/Te crystal, a high speed pulse amplifier, acomparator and a 16bit counter were basic components of a X-ray detector. First, a Cd/Te crystal catches a X-ray photon and makes a electric pulse signal wich voltage is in proportion to the X-ray photon energy. Second, a high speed pulse amplifier amplifies that electrical pulse. Third, noise component of electrical signal is cutting off by comparator. Forth, pulse of purified electrical signal is counted by the comparator. In this way, a pixel values are measured. 2 dimensional sensor which size was about 2x130 mm was made. This sensor was equipped on the specially made dental panoramic X-ray machine AZ3000^<TM>. This machine could perform scanography, then the cephalometric radiography was taken as a scanned radiography technique. This system was almost 20 times high sensitive compared with a conventional screen-film system.To watch a cephalometric images, X-ray image viewing station was made. This viewing system was based on DICOM3.0 standard and had a Hyper Text base user interface.