External dose quantities used in radiation protection and dosimetry According to the ICRP, the main uses of<unk> are the prospective dose assessment for planning and optimisation in radiological protection, and demonstration of compliance with dose limits for regulatory purposes. The<unk> is thus a central dose quantity for regulatory purposes. The ICRP also says that<unk> has made a significant contribution to radiological protection as it has enabled doses to be summed from whole and partial body exposure from external radiation of various types and from intakes of radionuclides. Usage for external dose The calculation of<unk> is required for partial or non-uniform irradiation of the human body because equivalent dose does not consider the tissue irradiated, but only the radiation type. Various body tissues react to ionising radiation in different ways, so the ICRP has assigned sensitivity factors to specified tissues and organs so that the effect of partial irradiation can be calculated if the irradiated regions are known. A radiation field irradiating only a portion of the body will carry lower risk than if the same field irradiated the whole body. To take this into account, the<unk>  to the component parts of the body which have been irradiated are calculated and summed. This becomes the<unk> for the whole body, dose quantity . It is a "protection" dose quantity which can be calculated, but cannot be measured in practice. An<unk> will carry the same<unk>  risk to the whole body regardless of where it was applied, and it will carry the same<unk>  risk as the same amount of equivalent dose applied uniformly to the whole body. Usage for internal dose<unk> can be calculated for committed dose which is the internal dose resulting from inhaling, ingesting, or injecting radioactive materials. The dose quantity used is: Committed<unk>  is the sum of the products of the committed organ or tissue equivalent doses and the appropriate tissue weighting factors , where is the integration time in years following the intake. The commitment period is taken to be 50 years for adults, and to age 70 years for children.
Effective dose 
Equivalent dose
Threshold dose
Absorbed dose
Reference dose
Dose area product
Lethal dose
Minimum alveolar concentration