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Investigation of calibration-based projection domain dual energy decomposition CBCT technique for brain radiotherapy applications

Publication ,  Conference
Sajja, S; Hashemi, M; Huynh, C; Mainprize, JG; Eriksson, M; Lee, Y; Nordstrom, H; Nico, A; Yin, FF; Sahgal, A; Ruschin, M
Published in: Progress in Biomedical Optics and Imaging - Proceedings of SPIE
January 1, 2019

The purpose of the present study was to develop and evaluate a practical dual-energy imaging approach for enhancing on-board cone-beam CT (CBCT) image quality for brain radiotherapy applications. The proposed primary technique involves a projection domain calibration procedure. In-house fabricated aluminum and acrylic step wedges were stacked and oriented orthogonally to each other to produce 72 unique combinations of two-material path lengths, i.e. 8 acrylic steps × 9 aluminum steps. High (120 kV) and low (70 kV) energy projections were acquired of the step wedges and a 3rd order polynomial fit was used to map the log-normalized projection intensities to the known acrylic and aluminum thicknesses. The subsequent model was tested on two phantoms: 1) in-house DE phantom with PMMA background and calcium inserts of different concentrations (5 mg/mL, 200 mg/mL and 400 mg/mL) and 2) a RANDO head phantom. The decomposed projections were reconstructed separately as aluminum-only and acrylic-only reconstructions. In addition, virtual monochromatic projections (VMPs) obtained by combining the aluminum-only and acrylic-only projections were reconstructed at different keVs. A quantitative improvement was observed in the SDNR (signal difference to noise ratios) of the calcium inserts using Aluminum-reconstructions and synthesized VMPs (40 to 100 keV) compared to the single energy reconstructions. A reduction in beam hardening was observed as well. In addition, a qualitative improvement in soft-tissue visualization was observed with the RANDO phantom reconstructions. The findings indicate the potential of dual energy CBCT images: material specific images as well as VMPs for improved CBCT-based image guidance. The present approach can readily be applied on existing commercial systems and a feasibility study on patients is a worthwhile investigation.

Duke Scholars

Published In

Progress in Biomedical Optics and Imaging - Proceedings of SPIE

DOI

ISSN

1605-7422

ISBN

9781510625433

Publication Date

January 1, 2019

Volume

10948
 

Citation

APA
Chicago
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Sajja, S., Hashemi, M., Huynh, C., Mainprize, J. G., Eriksson, M., Lee, Y., … Ruschin, M. (2019). Investigation of calibration-based projection domain dual energy decomposition CBCT technique for brain radiotherapy applications. In Progress in Biomedical Optics and Imaging - Proceedings of SPIE (Vol. 10948). https://doi.org/10.1117/12.2510430
Sajja, S., M. Hashemi, C. Huynh, J. G. Mainprize, M. Eriksson, Y. Lee, H. Nordstrom, et al. “Investigation of calibration-based projection domain dual energy decomposition CBCT technique for brain radiotherapy applications.” In Progress in Biomedical Optics and Imaging - Proceedings of SPIE, Vol. 10948, 2019. https://doi.org/10.1117/12.2510430.
Sajja S, Hashemi M, Huynh C, Mainprize JG, Eriksson M, Lee Y, et al. Investigation of calibration-based projection domain dual energy decomposition CBCT technique for brain radiotherapy applications. In: Progress in Biomedical Optics and Imaging - Proceedings of SPIE. 2019.
Sajja, S., et al. “Investigation of calibration-based projection domain dual energy decomposition CBCT technique for brain radiotherapy applications.” Progress in Biomedical Optics and Imaging - Proceedings of SPIE, vol. 10948, 2019. Scopus, doi:10.1117/12.2510430.
Sajja S, Hashemi M, Huynh C, Mainprize JG, Eriksson M, Lee Y, Nordstrom H, Nico A, Yin FF, Sahgal A, Ruschin M. Investigation of calibration-based projection domain dual energy decomposition CBCT technique for brain radiotherapy applications. Progress in Biomedical Optics and Imaging - Proceedings of SPIE. 2019.

Published In

Progress in Biomedical Optics and Imaging - Proceedings of SPIE

DOI

ISSN

1605-7422

ISBN

9781510625433

Publication Date

January 1, 2019

Volume

10948