The method for determining an infusion and/or injection region for infusing and/or injecting a medical drug into a heterogeneous body structure to achieve a distribution of the medical drug in a desired target region of the heterogeneous body structure, comprises determining the infusion and/or injection region from which the medical drug is to be transported through the heterogeneous body structure to the target region as a function of a property of the body structure and a position of the desired target region. The method for determining an infusion and/or injection region for infusing and/or injecting a medical drug into a heterogeneous body structure to achieve a distribution of the medical drug in a desired target region of the heterogeneous body structure, comprises determining the infusion and/or injection region from which the medical drug is to be transported through the heterogeneous body structure to the target region as a function of a property of the body structure and a position of the desired target region, determining a loss of the drug in segments of the body structure based on the property of the body structure, calculating a probability for the connectivity and/or loss of the drug for the segments, determining the suitable segments for an injection to achieve a predetermined distribution of the drug in the target region using the calculated probability, visually displaying a possible drug transport paths from the determined infusion and/or injection region to the target region, a probability for each segments of the heterogeneous body structure that a distribution of the medical drug in the target region will be achieved when infusing and/or injecting the drug into the corresponding segments, a connectivity of adjacent segments, a loss of the drug in segments or a possible segments of the heterogeneous body structure suitable for the injection, calculating an expected ratio between a concentration and/or amount of the medical drug in the target re
