Abstract: A system, method and computer program product to determine radiation dose from radionuclides used to treat a patient in need thereof. The present invention allows users to visualize and understand the impact of radionuclide choice, distribution of activity in the cell, distribution of activity among the cells, cell dimensions, cell separation distance, cluster size, and radiobiological response parameters on the capacity to kill populations of cells. All of these parameters can play a substantial role in determining the surviving fraction of cells. Accordingly, this system, method and computer program product can assist in designing treatment plans for therapeutic radiopharmaceuticals suited to individual needs.