Roentgen meaning

In legal practice, roentgen (R) appears mainly in legacy radiation records, expert reports and historic or US-sourced evidence. It is an obsolete unit of radiation exposure in air, indicating the amount of ionising radiation that produces a specified electric charge in dry air at standard conditions (1 R = 2.58 × 10^-4 C/kg). Because it measures exposure in air, it is not a direct measure of absorbed dose in tissue or of legal dose to persons. Current radiation protection law and guidance in England & Wales, Scotland, Northern Ireland and Ireland use SI units and do not define or rely on the roentgen. Regulatory limits and compliance documents are expressed in sieverts (Sv) for effective/equivalent dose, grays (Gy) for absorbed dose, becquerels (Bq) for activity, and coulomb per kilogram (C/kg) for exposure (for example, under the Ionising Radiations Regulations 2017 in Great Britain and equivalent regimes implementing the Euratom Basic Safety Standards). Where roentgen values arise in litigation, regulatory enforcement or insurance claims, practitioners should obtain expert conversion and context. Any comparison with statutory dose limits must be made via appropriate conversions (R to C/kg, Gy and/or Sv) and assumptions about radiation energy and medium. Usage is broadly consistent across the UK...