Reducing the risk of skin injuries in cardiac catheterization procedures: Optimization proposal for obese patients.

PURPOSE: During interventional cardiology procedures, high doses of X-ray may be delivered to patients. This is especially critical in cases of obese patients and/or high obliquity projections. High dose rates can then be produced in patients' skin as well as insufficient image quality due to regulatory limitations in the X-ray tube output working in the fluoroscopy mode. In this paper, an optimization action is proposed to reduce patient entrance dose rate and preserve image quality in cases of thick patients.

METHODS: The action is based on the evaluation of dose rate to the patient and image quality in a new fluoroscopy protocol with less frame rate (7.5 vs. 15 frames/s) and higher spectral shape filter (0.4 vs. 0.1 mm Cu). The new protocol is tested in an angiography room using a PMMA phantom and a test object.

RESULTS: The new fluoroscopy protocol (7.5 fr/s and 0.4 mm Cu) reduces entrance surface air kerma in 70%-10% (depending on PMMA thickness), preserving the incident air kerma per frame at the image detector. While at lower PMMA thickness, the MTF measured with bar pattern is better for the default protocol; at PMMA thickness between 32 and 37 cm, the optimized protocol produces better image quality indicators.

CONCLUSIONS: This work demonstrates that in the case of high thicknesses of PMMA (32-37 cm), increasing spectral beam filter and reducing frame rate may help improve image quality and maintain entrance surface air kerma so as to fulfil the regulatory requirements.