1. A method for detecting and excising nonpalpable lesions, comprising the steps of: (a) injecting at least one hematoma into a mammal's breast to target a nonpalpable lesion; wherein the hematoma comprises approximately 2 ml to about 5 ml of the mammal's own blood; (b) detecting the location of the targeted lesion using MRI; and thereafter (c) excising the targeted lesion.