Research Of The Key Problems Of Capturing The Time In The Fast Electronic Pulse In PET And Acquisition Scheme

Positron emission tomography (PET) is one of the most advanced nucleus medicine diagnosis and research techniques which can provide the tomographic image of the distribution of the radiotracer in the living organism noninvasively. This thesis concentrated on the research of capturing the time in the fast electronic pulse in PET and the related key issues. We gained the progress in the following aspects.For the high cost of the normal single high-speed analog-digital convertor sampling the fast electronic pulse in PET, the thesis led the technique of multi-chip AD parallel sampling into the process of digitalizing the fast electronic pulse in order to reduce the cost of the time information capturing system. First, analyze the mathematical theory of parallel sampling. Then design the software and hardware system of electronic pulse sampling and displaying via micro-controller unit controlling two chips of ADC. At last, reconstruct the original input signal without distortion and completely.In order to grasp the law of the fast electronic pulse’switching time in PET more deeply, predict the probability of accumulated pulses’occurrence. The thesis constructed the scintillation crystal LYSO PET detector ring’s computer simulation model based on the nuclear medicine development tools-----GATE (Geant4Application for Tomographic Emission). Furthermore, gathered the action time information of gamma photon and detectors under the typical radioactive intensity via2D and3D two different methods.In the foundation of the works above, the thesis developed the source code to extract the fast electronic pulse switching time interval, using the computer simulation model’s output to extract the related data, constructing the probability distribution histogram of the fast electronic pulse switching time interval. Researching the maximum likelihood parameter estimation of negative exponential distribution and its mathematical implementation process, solving the parameter and doing the hypothesis testing which provided the guidance basis to the parameter designing in the PET time screening system.