Method and system for recovering scintillation pulse information

A method for recovering scintillation pulse information, implemented by a PET or a nuclear measurement apparatus which comprises a detector, wherein the method comprises:

• step S1:
• acquiring, by the detector, a scintillation pulse database of non-stacked compliance single events in a low count, and building a scintillation pulse noise model for the scintillation pulse database of the single events by a simulation or experimental measurement, wherein an average pulse is calculated for the scintillation pulse database of the non-stacked compliance single events, and scintillation pulse shape information is given by the average pulse, and wherein the detector comprises an LYSO crystal and a Hamamatsu R9800 PMT, an LYSO crystal and an FM300035 SIPM, or an LaBr crystal and an Hamamatsu R9800 PMT;
• step S2:
• calculating a posterior probability logarithm value for a given energy value based on the scintillation pulse noise model, comprising:
• step 2.1:
• loading a scintillation pulse segment S0, and calculating a likelihood function of the given energy value based on the pulse noise model, wherein the scintillation pulse segment starts at a time point t0 at which the scintillation pulse segment passes upwards a threshold v1, and the scintillation pulse segment ends at a time point t0+Δt, with Δt being greater than two times of a time constant of a falling edge of a scintillation crystal;
• and
• step 2.2:
• calculating logarithms for all of the time points and adding up the logarithms, to obtain a value of a function having same monotonicity as a posterior probability function;
• and
• step S3:
• performing step S2 repeatedly to obtain an energy value meeting a maximal posterior probability condition, comprising:
• step 3.1:
• calculating posterior probabilities for different tentative energy values by repeatedly performing step S2 as a module;
• step 3.2:
• searching linearly for the energy value meeting the maximal posterior probability condition;
• and
• step 3.3:
• after the energy value is obtained, correcting a time origin for step 2.1 based on the energy value and repeating step 3.1 and step 3.2;
• step S4:
• obtaining an energy spectrum with an improved energy resolution according to the energy value obtained from step S3.