Cardiac catheterisation and angiography uses ionising radiation and therefore produces a radiation dose to the patient and to the operating staff. The dose to the patient can be measured using thermoluminescent dosemeters placed on the skin or by using a large-area detector attached to the x ray tube to measure the dose–area product (DAP) for the incident x ray beam (DAP meter). The DAP is particularly useful for assessing and comparing the radiation dose from screening procedures. It provides a more useful indication of the overall patient exposure than measurement of surface dose at particular locations. The dose measurement is used either as a surrogate for radiation risk or as a step in actually estimating the risk. Published factors allow conversion of the DAP to effective dose, a derived quantity in which doses to different organs or tissues are weighted according to their radiosensitivity and summed to give a risk-related dose quantity.^1–5

UK legislation does not give dose limits for patients undergoing medical diagnostic exposures, but requires adherence to the “as low as reasonably practicable” principle, and comparison of doses with diagnostic reference levels for common procedures. Published data for patient exposure, absorbed dose, effective dose and risk of malignancy from the different specific diagnostic cardiac catheterisation procedures are incomplete, and there are no national diagnostic reference levels for individual procedures.

We undertook this study with the aim of establishing local patient doses for six different diagnostic cardiac catheterisation procedures …