A method of determining an internal three-dimensional thermallydistinguishable region in the living body is disclosed.The method comprises obtaining a synthesized thermospatial image defined overa three-dimensional spatial representationof the living body and having thermal data arranged gridwise over a surface ofthe three-dimensional spatial representation in a pluralityof picture-elements each represented by a intensity value over the grid. Themethod further comprises searching over the gridfor at least one set of picture-elements represented by generally similarintensity values. For at least a few sets of picture-elements,the method defines a plurality of loci, each locus being associated with atleast a pair of picture-elements of the set and defined suchthat each point of the locus is at equal thermal distances from individualpicture-elements of the pair. The plurality of loci is usedfor determining the internal three-dimensional thermally distinguishableregion.
