Objective To assess whether the implementation of a protocol of digital screen based magnification during diagnostic and interventional cardiac catheter laboratory procedures results in a change in radiation exposure compared to an x-ray tube magnification method. The study was based on a experiment with a stent implanted in a Lungman phantom. Using standard X-ray tube positions in cardiac angiography which showed that use of digital magnification reduced radiation exposure by 20% compared to using tube determined magnification in an cardiac configured X-Ray machine. Using digital...

A retrospective analysis of the radiation exposure and patient procedural databases to compare the measuredDose Area Product(DAP) recorded during the period when a tube-based magnification protocol was used and when the screen based digital magnification protocol was adopted. Analysis was carried out for patients having a diagnostic coronary angiogram and for patients having an interventional coronary procedure where one or more stents were implanted. Patient doses were recorded by radiographers and medical physicists and correlated with patient weight and exposure time.

1508 procedures were analysed, 693 diagnostic coronary angiograms and 815 interventional procedures. A complete data set was available for patient DAP, number of acquisition runs, total radiation time (sum of time for all acquisitions plus fluoroscopy time), patients’ weight and sex. In the period using tube magnification median DAP was significantly higher at2124.5 µGy.m2(interquartile range (IQR) 1376 -3272) compared to 1401 µGy.m2(IQR 924 -2152)during the period when screen magnification was used, a 34% reduction in DAP during the period when screen magnification was used (p

This study conclusively demonstrated that for cardiac diagnostic angiographic procedures and cardaic interventional procedures there was a significant reduction in patient X-ray dose using only digital magnification. Personal dosimeters are currently being audited to see if there was a concurrent reduction in operator radiation dose. Reduction in operator radiation dose is becoming more relevent as interventional radiological and cardiac procedures are becoming longer and more complex with more recent evidence of the development of complications from lifetime radiation exposure from operators

All the investigators in this work are current employees or have worked in the North Wales Cardiac Centre during this study

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