assessment of x-ray crosstalk in a computed tomography scanner with small detector elements using monte carlo method

Introduction: crosstalk is a leakage of x-ray or light produced in a matrix of x-ray detectors or array of photodiodes in one element to other elements affecting on image contrast and spatial resolution. in this study, we assessed x-ray crosstalk in a computed tomography (ct) scanner with small detector elements to estimate the effect of various parameters such as x-ray tube voltage, detector element sizes, scintillator material, impurities in the scintillator material, and the material of detector separators on x-ray crosstalk. materials and methods: this study was performed using monte carlo simulation. in the first step, x-ray tube and its energy spectrum at the energies of 80, 100, 120, and 140 kev were simulated and validated by using spekcalc and t-test. then, other important parts of ct scanner, namely filters, detectors, and grids were simulated. x-ray crosstalk between ct detectors was calculated in air and in the presence of water phantom (as a simulator of human body) to compare the effect of scattered photons. finally, the influence of some important parameters on x-ray crosstalk was evaluated. results: in ct scanner with small elements, when using phantom, crosstalk increases by 16-50%. using the lowest possible energies of x-ray, decreases the crosstalk up to 43% of its initial amount. furthermore coating a 10 or 20 μm layer of tungsten or lead on the detector separators, decreases the x-ray crosstalk significantly. conclusion: choosing the proper high voltage, detectors’ material and its dimensions, scintillator impurities and septa material can decrease x-ray crosstalk.