Changes

The primary aim of radiological protection is to provide an appropriate standard of protection for people and the environment without unduly limiting the beneficial practices giving rise to radiation exposure. [[ICRPPublication 103]]<ref name="Pub103">[[ICRP Publication 103]] The 2007 Recommendations of the International Commission on Radiological Protection. Ann. ICRP 37(2-4), 2007.</ref> has formulated a set of fundamental principles of radiological protection that apply to radiation sources and to the individuals being exposed ([[ICRP Publication 103]] The 2007 Recommendations of the International Commission on Radiological Protection ). Such These principles are applicable to radiological protection in healthcare for the protection of patients, family members and other carers, the general public, volunteers in biomedical research, and healthcare providersmedicine. ICRP has provided specific recommendations for medical settings protection in medicine through [[ICRP Publication 105]] Radiological Protection in Medicine<ref name="Pub105">[[ICRP Publication 105]] Radiological Protection in Medicine. Ann. ICRP 37(6), 2007.</ref>, [[ICRP Supporting Guidance 2]] Radiation and your patient - A Guide for Medical Practitioners <ref>[[ICRP Supporting Guidance 2]] Radiation and Your Patient A Guide for Medical Practitioners. Ann. ICRP 31(4), 2001.</ref> and [[ICRP Publication 73]] Radiological Protection and Safety in Medicine<ref name="Pub073">[[ICRP Publication 73]] Radiological Protection and Safety in Medicine. Ann. ICRP 26(2), 1996.</ref>.

Radiation exposure can lead to either tissue reactions or stochastic effects ([[ICRP Publication 103]], Annex A). <ref name="Pub103"/> Tissue reactions (<ref name="Pub118">[[ICRP Publication 118]] CRP ICRP Statement on Tissue Reactions / and Early and Late Effects of Radiation in Normal Tissues and Organs – Threshold Doses for Tissue Reactions in a Radiation Protection Context. Ann. ICRP 41(1-2) , 2012.</ref> can occur in the application of ionizing radiation in radiation therapy, and in interventional procedures, particularly when fluoroscopically guided interventional procedures are complex and require longer fluoroscopy time or acquisition of numerous images. Tissue reactions occur when many cells in an organ or tissue are killed, the effect will only be clinically observable if the radiation dose is above some threshold. The magnitude of this threshold will depend on the dose rate (i.e. dose per unit time) and linear energy transfer of the radiation, the organ or tissue irradiated, the volume of the irradiated part of the organ or tissue, and the clinical effect of interest.

Stochastic effect (somatic or heritable) increases with radiation dose and is probably proportional to dose at low doses and low dose rates <ref name="Pub099">[[ICRP Publication 99]] Low-dose Extrapolation of Radiation-related Cancer Risk. Ann. ICRP 35(4), 2005.</ref> ([[ICRP Publication 99]] Low-dose Extrapolation of Radiation-related Cancer Risk). At higher doses and dose rates, the probability often increases with dose more markedly than simple proportion. At even higher doses, close to the thresholds of tissue reactions, the probability increases more slowly, and may begin to decrease as a result of the competing effect of cell killing. It is not feasible to determine on epidemiological grounds alone that there is, or is not, an increased risk of cancer for members of the public associated with absorbed doses of the order of 100 mGy or below. The linear non-threshold model remains a prudent basis for the practical purposes of radiological protection at low doses and low dose rates.