An Observation of the amount of radiation to which the Patient has been or is expected to be exposed. Such data can help clinicians determine if the benefit from the diagnostic information provided by an individual examination (or additional examinations) outweigh the risk that may be associated with a proposed imaging exam. Retrospectively, it may be necessary to know how much radiation to which the Patient was exposed. As an example, if it was later learned that the Patient was pregnant at the time of exposure, it would be helpful to know the kind and quantity of radiation to which the fetus might have been exposed. Radiation exposure is typically measured in equivalent doses, expressed using Sieverts (Sv), or roentgen equivalents in man (rem). The equivalent dose is itself derived from the amount of ionizing radiation (dose) expressed in Gray (Gy) or rad. The dose is derived from the exposure expressed in Coulomb per kilogram (C/kg) or roentgen (R).