Study On The Effects Of Radiation Outside Field Of View On The Quantitation Of PET Imaging

Positron Emission Tomography(PET) is a kind of noninvasive nuclear medical imaging technique, which can demonstrate the vivo metabolic information at molecular level, it has been widely used in the diagnosis and cure of oncology, cardiovascular and nervous system disease. Small animal PET is designed for molecular imaging of small animal models, which can explore the physical characteristics of various disease models and provide referential information for clinical research.Because of the size of field of view(FOV), the subject can not be placed in the FOV entirely, then there are a mass of radiation outside of FOV(ROFOV). It not only results in increased scatter and random coincidences, but also decreased true coincedences. Furthermore, it may undermine the image authenticity. Therefore, it is necessary to evaluate the effects of the ROFOV on image quantification.This paper is based on small animals Trans-PET, we used quantitative analysis to discuss the influence of ROFOV on cylindrical phantom and rat brain imaging studies. Fistly the quantitative differences of inside the axial-field-of-view by the impact of ROFOV was analyzed, we enacted the quentitative difference analysis method in the follow-up experiments according to the conclusions. Then we compared the quentitative differences with different dose of ROFOV. After that, we designed the dynamic scanning, which is used for assessing whether the quentitative differences is changed with the radiation decaying. Finally, in order to futher validation, we developed a body shield for the SD rats brain imaging, and contrasted the quantitation of every brain area with and without the body shield. In additon, we chose the coincidence rate as a index to evaluate the influence of the ROFOV on image quality.According to the conclusions got from this paper, the ROFOV will reduce the quantitation accuracy and image quality. We hope that this work will benefit for the more precise quantitative analysis of PET imaging research.