Impact of a high aspect ratio antiscatter grid for coronary angiography imaging on imaging system dose efficiency

Nicholas Marshall; Michiel Dehairs; Hannelore Verhoeven; Hilde Bosmans

doi:10.1117/12.2613036

4 April 2022 Impact of a high aspect ratio antiscatter grid for coronary angiography imaging on imaging system dose efficiency

Nicholas Marshall, Michiel Dehairs, Hannelore Verhoeven, Hilde Bosmans

Author Affiliations +

Proceedings Volume 12031, Medical Imaging 2022: Physics of Medical Imaging; 1203105 (2022) https://doi.org/10.1117/12.2613036
Event: SPIE Medical Imaging, 2022, San Diego, California, United States

Abstract

Aim: To evaluate the impact of a high ratio antiscatter grid on imaging system dose efficiency using a spatial frequency domain figure of merit, for coronary angiography applications. Methods: Four imaging conditions were assessed: a source-image receptor distance (SID) of 105cm, used with and without the standard 15/80 grid, and an SID of 120cm used with and without the new 29/80 grid. Automatic dose rate control (ADRC) x-ray factors were generated for these conditions and used to image a composite phantom, with each slab made of 20 mm poly(methyl)methacrylate (PMMA), 2 mm Al and 7 mm expanded polystyrene. Total phantom thickness ranged from 9 cm to 44 cm. An Fe square was included in the phantom and imaged at the iso-centre. Signal difference to noise ratio (SDNR) was measured and multiplied by modulation transfer function (MTF) based weighting factors to give SDNR(u), along with additional factors to account for the influence of SID and DQE. A figure of merit (FOM) defined as SDNR²(u)/K was used to compare the four conditions, where K is the air kerma at the interventional reference point. Results: Below phantom thicknesses of ~20 cm, neither grid improved system dose efficiency compared to imaging without grid. For thicknesses of 30 cm up to 44 cm, dose reduction using the 29/80 grid compared to the 15/80 grid ranged from 10% to 48%. Conclusion: Evaluation using the SDNR²(u) based FOM showed that the 29/80 grid reduced dose by up to 48% compared to the current 15/80 grid, for phantom thicknesses above 24 cm.

Conference Presentation

Citation Download Citation

Nicholas Marshall, Michiel Dehairs, Hannelore Verhoeven, and Hilde Bosmans "Impact of a high aspect ratio antiscatter grid for coronary angiography imaging on imaging system dose efficiency", Proc. SPIE 12031, Medical Imaging 2022: Physics of Medical Imaging, 1203105 (4 April 2022); https://doi.org/10.1117/12.2613036

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