Numerical simulation of scintillant decay constant effect on radiation source boundary measurment

In the measurement of radiation source boundary using radiation imaging system, time diffusion of scintillant affects the measurement result. We constructed a type of radiation source having different intensity time width, boundary diffusion speed and relative intensity, then computed the deviation betweens boundary real size with the sizes in cases of scintillants BC408, LaBr3 and LSO respectively, by means of convolution and image intensity gradient. The results show that while photography time is 20 ns, deviation will be the smallest with the scintillant BC408; since a scintillator is not suitable for the measurement when deviation is greater than 1mm, the minimum values of intensity time width should be 266 ns, 133 ns and 33 ns for scintillants LSO, LaBr3 and BC408, respectively; however, the deviation doesnt vary with scintillant materials in complete integral imaging. Finally, a formula is summed up for deviation computation, which can well reflect the trend of real deviation.