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Radiation hazards for the patient in cardiological procedures

2001; BMJ; Volume: 85; Issue: 2 Linguagem: Inglês

10.1136/heart.85.2.127

2053-5864

Peter J. Wilde,

Cardiovascular Syncope and Autonomic Disorders

Radiation hazards for the patient in cardiological proceduresThe radiation dose to both staV and patients in interventional cardiology and radiology procedures is high compared to diagnostic procedures, particularly in the cardiological techniques of percutaneous coronary intervention (PCI) and radiofrequency ablation as well as developing techniques such as direct myocardial revascularisation.In considering the potential harmful eVects of radiation it is necessary to consider eVects on the patients themselves as well as the staV performing the procedure.There is considerable experience relating to the exposure of staV and increasing awareness of the importance of radiation protection for the staV and patients.Regulations covering both groups have been in place for 10-15 years.The aim of this article is to review the radiation hazards to the patient and the radiation protection measures taken to ensure that the risk to the patient is kept as low as reasonably practicable.In addition it will review the newly implemented Ionising Radiation Regulations. Radiation biologyThere are two main biological eVects of ionising radiation: deterministic and stochastic.Deterministic eVects are those in which the number of cells lost in an organ or tissue is so great that there is a loss of tissue function.The harm will not occur below a threshold and above this the severity of the eVect will increase with dose.Skin erythema and ulceration are examples of deterministic eVects.Stochastic eVects occur if an irradiated cell is modified rather than killed and then goes on to reproduce.The result may be the manifestation of a cancer after a prolonged and variable delay called the latent period.Stochastic eVects do not appear to have a threshold and the probability of the eVect occurring is related to the radiation dose.The International Commission for Radiation Protection (ICRP), an international professional body, produce recommendations which are the basis for the conceptual framework and key principles of radiation protection world wide.The current international recommendations 1 (ICRP 60) lay out the principles of justification, optimisation, and limitation of all radiation exposures.While there are no specified dose limits for patients, the main principle is that all deterministic eVects should be avoided while optimising radiation exposure to gain maximum diagnostic accuracy with minimum dose.In most interventional procedures the doses are such that only stochastic eVects need to be considered for radiation protection purposes, but recently a number of cases of skin erythema, necrosis and ulceration have been reported in the USA 2 3 and Europe. 4The case reports 5 published recently in this journal are two such examples.Unfortunately such problems generally come to light when reported by others and so there is usually little information about the procedure and radiation doses used to produce the damage as in the current reports.Nevertheless such cases serve as important examples of how things can go wrong.