Radiation Protection (ICRP) guidance states that if a personal dosimeter is worn on a position on the body representative of its exposure, assuming whole-body exposure, the value of personal dose equivalent Hp(10) is sufficient to estimate an effective dose value suitable for radiological protection. Such devices are known as "legal dosimeters" if they have been approved for use in recording personnel dose for regulatory purposes. In cases of non-uniform irradiation such personal dosimeters may not be representative of certain specific areas of the body, where additional dosimeters are used in the area of concern. In certain circumstances, a dose can be inferred from readings taken by fixed instrumentation in an area in which the person concerned has been working. This would generally only be used if personal dosimetry had not been issued, or a personal dosimeter has been damaged or lost. Such calculations would take a pessimistic view of the likely received dose. Internal dose Internal dosimetry is used to evaluate the committed dose due to the intake of radionuclides into the human body. Medical dosimetry Medical dosimetry is the calculation of absorbed dose and optimization of dose delivery in radiation therapy. It is often performed by a professional health physicist with specialized training in that field. In order to plan the delivery of radiation therapy, the radiation produced by the sources is usually characterized with percentage depth dose curves and dose profiles measured by a medical physicist. In radiation therapy, three-dimensional dose distributions are often evaluated using a technique known as gel dosimetry. Environmental dosimetry Environmental Dosimetry is used where it is likely that the environment will generate a significant radiation dose. An example of this is radon monitoring. Radon is a radioactive gas generated by the decay of uranium, which is present in varying amounts in the earth's crust. Certain geographic areas, due to the underlying geology, continually generate radon which permeates its way to the earth's surface. In some cases the dose can be significant in buildings where the gas can accumulate. A number of specialised dosimetry techniques are used to evaluate the dose that a building's occupants may receive. Measures of dose To enable consideration of stochastic health risk, calculations are performed to convert the physical quantity absorbed dose into equivalent and effective doses, the details of which depend on the radiation type and biological context. For applications in radiation protection and dosimetry assessment the (ICRP)