Focused transducers with a central hole are widely used in high-intensity focused ultrasound applications. The spatial averaging effects of hydrophones when characterizing the field characterization of such transducers should be reckoned. The analytical model derived based on Fresnel approximation will end up with multiple integrals, which is very time consuming to be computed. In this research, a fast estimation method for spatial averaging correction of hydrophones when characterizing such transducers based on multi-Gaussian beam model is developed, the computer optimization is used to evaluate the coefficients. Generally, the spatial averaging effects will result in an underestimation of the absolute acoustic pressure amplitudes. The results derived based on the multi-Gaussian beam model are compared with the Fresnel approximation, which agreed well with each other.
