A computer-implemented method of estimating drug delivery at a target tissue, the method comprising: receiving a patient-specific anatomical model of at least one vessel of the patient and a target tissue where a drug is to be supplied, the patient-specific anatomical model being derived from one or more images of the patient; receiving patient-specific information defining the administration of a drug; identifying one or more locations in the target tissue where drug delivery data will be estimated or measured; deriving patient-specific data from the patient specific anatomical model and/or the patient; determining one or more blood flow characteristics in a vascular network leading to the one or more locations in the target tissue where drug delivery data will be estimated or measured, using the patient-specific anatomical model and the patient-specific data; determining the transportation, spatial, and/or temporal distribution of the drug particles in one or more locations in the vascular network using the patient-specific information defining the administration of the drug; computing drug delivery data at the one or more locations in the target tissue using the transportation, spatial, and/or temporal distribution of the drug particles; receiving a desired drug delivery data at one or more locations in the target tissue; assessing the effectiveness of the current drug delivery system by comparing actual drug delivery data at the one or more locations in the target tissue with the desired drug delivery data at the one or more locations in the target tissue; and reconfiguring the drug administration so that said actual drug delivery data at the one or more locations in the target tissue matches or falls within range of the desired drug delivery data at the one or more locations in the target tissue; wherein the reconfiguring the drug administration includes systematically adjusting one or more of a drug amount, a drug concentration, a drug administration location, a drug administration frequency, a route of drug administration, an administration time, or a combination thereof, in order to increase the effectiveness of the current drug delivery system. receiving a patient-specific anatomical model of at least one vessel of the patient and a target tissue where a drug is to be supplied, the patient-specific anatomical model being derived from one or more images of the patient; receiving patient-specific information defining the administration of a drug; identifying one or more locations in the target tissue where drug delivery data will be estimated or measured; deriving patient-specific data from the patient specific anatomical model and/or the patient; determining one or more blood flow characteristics in a vascular network leading to the one or more locations in the target tissue where drug delivery data will be estimated or measured, using the patient-specific anatomical model and the patient-specific data; determining the transportation, spatial, and/or temporal distribution of the drug particles in one or more locations in the vascular network using the patient-specific information defining the administration of the drug; computing drug delivery data at the one or more locations in the target tissue using the transportation, spatial, and/or temporal distribution of the drug particles; receiving a desired drug delivery data at one or more locations in the target tissue; assessing the effectiveness of the current drug delivery system by comparing actual drug delivery data at the one or more locations in the target tissue with the desired drug delivery data at the one or more locations in the target tissue; and reconfiguring the drug administration so that said actual drug delivery data at the one or more locations in the target tissue matches or falls within range of the desired drug delivery data at the one or more locations in the target tissue; wherein the reconfiguring the drug administration includes systematically adjusting one or more of a drug amount, a drug concentration, a drug administration location, a drug administration frequency, a route of drug administration, an administration time, or a combination thereof, in order to increase the effectiveness of the current drug delivery system.