Systems, methods, and computer program products that enable calculating the water equivalent diameter of an exposed subject by defining a patient object using anterior/posterior (AP) and lateral (LAT) scout images are provided. Pixels corresponding to air in the LAT and AP scout image are determined. Pixels outside the of the air area belong to either to the patient or the table. The table for both the LAT and AP scout images is identified. The remaining pixels in the LAT AP scout images are from the patient. For each segmented object (patient or table) the boundaries of the segmented object are identified and the attenuations within the segmented boundaries are computed. The final shape and attenuation values of the patient is stored and the size-specific dose estimate (SSDE) is calculated. The water equivalent diameter value is normalized by using the technical acquisition parameters provided by the acquisition device.
