A Preliminary Study Of A High Sensitivity SPECT System

Small animal imaging is a very important field of the medical imaging, it is often used in pre-clinic research and small animal model experiment. In recent years, with the development of the imaging technology and the deepening of the research, it is required that the imaging system can give the dynamic biologic processes and the drug distribution in the living body. In order to achieve the target, the imaging system must have a very high sensitivity to collect images in real time. The factor which directly affect the performance of the imaging system is the collimator. In traditional parallel-hole collimators or pin-hole collimators are used in small animal imaging, both of them have a high resolution but a low sensitivity, so a high sensitivity system is raised.The geometric efficiency is used to derive the point spread function (PSF) of a SPECT system which uses no collimator. The sensitivity of the no-collimator system can up to several tens of percent which is much better than traditional collimators, at the same time, the system has a reasonable sensitivity, so the no-collimator system can be used in the small animal imaging. It considered the thickness of the NaI crystal and made a modification of the PSF. By the comparison of the results before and after the modification, the necessity of the modification is evident.It is used an experiment with the y camera to support the derivation. So it showed the proof that the system had a high sensitivity and provided an acceptable image. Then Rose criterion was introduced to show that with a high sensitivity the influence of the noise was weakened because of the high sensitivity.