ESTRO 2024 - Abstract Book

S3849

Physics - Image acquisition and processing

ESTRO 2024

Based on these measurements, SNR and CNR across various VMI levels were computed to determine the ideal reconstruction parameters. VMI levels were varied from 40 to 100 keV in 5 keV increments.

Results:

Mean attenuation and noise level showed an energy dependency, both decreasing as VMI levels increased. Analysis of the data revealed improvements in SNR and CNR values with increasing VMI levels, culminating in an optimum VMI level. Depending on the material inserts, the optimal VMI level ranged between 65 and 75 keV. There, SNR and CNR values peaked, demonstrating superior SNR and CNR compared to single-energy CT scans. Compared to single-energy scans, the CNR and SNR increased by approximately 20%. In their study on optimizing of VMI for brain metastases delineation in the radiosurgical contexts, Karino et al. found the optimal energy level for VMI to be 63 keV, derived from contrast-enhanced DECT [2]. Mean attenuation values across diverse tissue types further emphasized the capability of VMI reconstructions to enhance tissue differentiation, affirming the potential clinical benefits of this optimization.

Conclusion:

This study underscores the significance of optimizing VMI reconstruction levels in DECT. Utilizing a sophisticated multi tissue phantom and advanced imaging technology, this research identifies a level of 70 keV as optimal for VMI reconstruction in DECT for superior tissue differentiation (in case of DECT imaging of the brain). This holistic phantom based approach highlights the potential of VMI reconstructions in enhancing image quality and ensures a comprehensive perspective on the optimization of imaging protocols, vital for the informed application of DECT in clinical practice.

Keywords: DECT, VMI, image quality

References:

[1] Kraft J , Lutyj P, Grabenbauer F, Ströhle S, Tamihardja J, Razinskas G, Weick S, Richter A, Huflage H, Wittig A, Flentje M, Lisowski D. Assessment of dual-energy computed tomography derived virtual monoenergetic imaging for target volume delineation of brain metastases. Radiother Oncol 2023; 187:109840. [2] Karino T, Ohira S, Kanayama N, Wada K, Ikawa T, Nitta Y, Washio H, Miyazaki M, Teshima T. Determination of optimal virtual monochromatic energy level for target delineation of brain metastases in radiosurgery using dual energy CT. Br J Radiol 2020;93:20180850.

1605

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