A modified method of Born's approximation is proposed. The essence of the method is that in real situations, the incident wave gains the object's speed, but not the medium's speed; which follows from the Fresnel formula. A solution algorithm for the weak-reflecting bio-organ's scattering problem is proposed in this task. The algorithm is based on a more precise definition of Born's approximation. Numerical and experimental research shows that the pathologies can have dimensions of about 1 mm, which can be identified according to echosignal spectrums. It is shown that norm and pathologies, like pectoral glands, are distinguished. If the pathology is less dense, there will be potent destruction in the echosignal spectrum. If pathology is denser, there will be less potent destruction. The proposed method permits one to classify the pathologies in bio-tissues more subtly.