A Digital X-ray Imaging System For Small-animal Studies

Digital imaging certainly seems to be the way of the future for diagnostic radiography. Digital X-ray imaging system is already replacing "plain" screen/film system in many imaging departments around the world, for its advantages of achieving, displaying, storing and communicating. It also can be used in non-destructive test in industry. A digital radiography system for small animal studies was introduced here. This system is a fiber-optics taper-coupled imaging system that is based on two CCD arrays. The x-ray source of the system has a small focal spot of 20μm. The system showed its advantage in terms of its properties of spatial resolution through the tradeoff between the geometric unsharpness and image magnification, and the measurement of modulation transfer function (MTF), noise power spectrum (NPS) and noise equivalent quantum (NEQ).In present paper, we studied digital X-ray imaging technology from two aspects. One is on extending the application area of digital X-ray imaging technology. This technique is applied in a different field, that is, in vivo observing x-ray attenuation of intratumor injection of indocyanine green, which provide a new approach for the studies in these fields according to its characteristic. Another is on measurement of X-ray detection limitation of blood vessel with tissues. The exponential curve fitting is used to obtain the values of the attenuation coefficient of tissues at different X-ray exposure. We also measure the X-ray attenuation of different blood vessels with different diameter, qualify the contrast between the tissues and the blood vessels when the diameter of the blood vessel and the thickness of the tissues are equal. Through these data, we obtain the critical thickness of the fat, which can just offer the contrast between blood vessel and tissues, and display in the screen at different X-ray exposure. All these data can be used in the optimization of the parameters of digital X-ray imaging with blood vessels. The main goal of developing a micro-CT system is to carry out high-resolution analysis in vitro or in vivo of biomedical samples as well as nondestructive testing of industrial components. The micro-CT system is based on the digital X-ray imaging system, and 3D information of specimen is carried out by the application of FDK cone-beam reconstruction algorithm. The micro-CT system has a high spatial resolution, which can provide images of high qualities. The mechanical part we designed is a 3-degrees system (x-y translation and z rotation). The rotation is controlled by a step motor.