A device and method for determining at least one infusion and/or injection region for infusing and/or injecting a medical drug into a heterogeneous body structure in order to achieve a distribution of the medical drug in a desired target region of the heterogeneous body structure is provided. The device and method provide at least one property of the heterogeneous body structure that influences the spatial distribution of the medical drug in the heterogeneous body structure; and determine the at least one infusion and/or injection region from which the medical drug is to be transported through the heterogeneous body structure to the at least one target region as a function of the at least one property of the heterogeneous body structure and a position of the desired target region.