Abstract. The paper presents a new algorithm to estimate the spatial heterogeneity of images, which is characterized by the number of patterns in the region of interest, their surface area, and the effective gradient between them. The application of the algorithm to quantify the spatial heterogeneity of the electromagnetic field from different loop radiators for radiofrequency hyperthermia showed that the applicator in the form of a circular arc produces a more heterogeneous field than the applicator with a straight profile does.

Keywords: spatially inhomogeneous field, moderate radio-frequency hyperthermia.