Nuclear Medicine Instrumentation, Quality Control And Image Correction

Nuclear medical imaging is functional imaging, which is broadly used in all kinds of fields, such as the detection of cancer, the studying of functional brain and the studying of cardiopathy.The primitive imaging obtained by nuclear medical instrument can not provide right information without correction. The position information of an emitted event has close relation with the energy information of it. We separate position information from energy information by position correction. Scatter photon can make distortion of the position of detected events. Scatter photon and yawp can be removed by energy window. Because of the character of calculating position of nuclear medical instrument, linearity and uniformity are not satisfactory in the primitive imaging. We use correction map to calibrate linearity and uniformity by software. In order to improving counts, we accomplish dead time correction by the relation between dead time and collection time.The index of quality control is important to the quality of collected imaging. By NEMA standard the measuring methods and automatic data analyzing are introduced in this paper.It is important for keeping the nuclear medical imaging quality to auto-adjust the gain of all PMTs identical. According to position information changing corresponding to the gain of all PMTs identical shifting, we can count adjusting coefficient of ECT. Light collecting efficiency of PMT in this position is in proportion to solid angles of PMT to the event in that position. The adjusting value was calculated by the algorism developed in the paper. The result showed that the algorism was effective in practice. We adjust some circuits by SCM according to adjusting coefficient.