Dose optimization in cardiac x-ray imaging

Journal Article · Sun Sep 15 04:00:00 EDT 2013 · Medical Physics

DOI:https://doi.org/10.1118/1.4818016· OSTI ID:22220445

Gislason-Lee, Amber J.; McMillan, Catherine; Cowen, Arnold R.; Davies, Andrew G. ^[1]

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1. LXi Research, Division of Medical Physics, University of Leeds, Worsley Building, Clarendon Way, Leeds LS2 9JT (United Kingdom)

Purpose: The aim of this research was to optimize x-ray image quality to dose ratios in the cardiac catheterization laboratory. This study examined independently the effects of peak x-ray tube voltage (kVp), copper (Cu), and gadolinium (Gd) x-ray beam filtration on the image quality to radiation dose balance for adult patient sizes.Methods: Image sequences of polymethyl methacrylate (PMMA) phantoms representing two adult patient sizes were captured using a modern flat panel detector based x-ray imaging system. Tin and copper test details were used to simulate iodine-based contrast medium and stents/guide wires respectively, which are used in clinical procedures. Noise measurement for a flat field image and test detail contrast were used to calculate the contrast to noise ratio (CNR). Entrance surface dose (ESD) and effective dose measurements were obtained to calculate the figure of merit (FOM), CNR{sup 2}/dose. This FOM determined the dose efficiency of x-ray spectra investigated. Images were captured with 0.0, 0.1, 0.25, 0.4, and 0.9 mm Cu filtration and with a range of gadolinium oxysulphide (Gd{sub 2}O{sub 2}S) filtration.Results: Optimum x-ray spectra were the same for the tin and copper test details. Lower peak tube voltages were generally favored. For the 20 cm phantom, using 2 Lanex Fast Back Gd{sub 2}O{sub 2}S screens as x-ray filtration at 65 kVp provided the highest FOM considering ESD and effective dose. Considering ESD, this FOM was only marginally larger than that from using 0.4 mm Cu at 65 kVp. For the 30 cm phantom, using 0.25 mm copper filtration at 80 kVp was most optimal; considering effective dose the FOM was highest with no filtration at 65 kVp.Conclusions: These settings, adjusted for x-ray tube loading limits and clinically acceptable image quality, should provide a useful option for optimizing patient dose to image quality in cardiac x-ray imaging. The same optimal x-ray beam spectra were found for both the tin and copper details, suggesting that iodine contrast based imaging and visualization of interventional devices could potentially be optimized for dose using similar x-ray beam spectra.

• OSTI ID: 22220445
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 9 Vol. 40; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CONTRAST MEDIA
COPPER
FLUOROSCOPY
IMAGES
OPTIMIZATION
PATIENTS
PHANTOMS
PMMA
RADIATION DOSES
X-RAY DETECTION
X-RAY SPECTRA
X-RAY TUBES