Development of hydrogel-based standards and phantoms for non-linear imaging at depth

Haseeb, Fizza; Bourdakos, Konstantinos N; Forsyth, Ewan; Setchfield, Kerry; Gorman, Alistair; Venkateswaran, Seshasailam; Wright, Amanda J; Mahajan, Sumeet; Bradley, Mark

Abstract

Significance: Rapid advances in medical imaging technology, particularly the development of optical systems with non-linear imaging modalities, are boosting deep tissue imaging. The development of reliable standards and phantoms is critical for validation and optimization of these cutting-edge imaging techniques.
Aim: We aim to design and fabricate flexible, multi-layered hydrogel-based optical standards and evaluate advanced optical imaging techniques at depth.
Approach: Standards were made using a robust double-network hydrogel matrix consisting of agarose and polyacrylamide. The materials generated ranged from single layers to more complex constructs consisting of up to seven layers, with modality-specific markers embedded between the layers.
Results: These standards proved useful in the determination of the axial scaling factor for light microscopy and allowed for depth evaluation for different imaging modalities (conventional one-photon excitation fluorescence imaging, two-photon excitation fluorescence imaging, second harmonic generation imaging, and coherent anti-Stokes Raman scattering) achieving actual depths of 1550, 1550, 1240, and 1240 μm, respectively. Once fabricated, the phantoms were found to be stable for many months.
Conclusions: The ability to image at depth, the phantom's robustness and flexible layered structure, and the ready incorporation of "optical markers" make these ideal depth standards for the validation of a variety of imaging modalities.

Citation

Haseeb, F., Bourdakos, K. N., Forsyth, E., Setchfield, K., Gorman, A., Venkateswaran, S., Wright, A. J., Mahajan, S., & Bradley, M. (2023). Development of hydrogel-based standards and phantoms for non-linear imaging at depth. Journal of Biomedical Optics, 28(12), Article 126007. https://doi.org/10.1117/1.JBO.28.12.126007%5D

• Journal Article Type: Article
• Acceptance Date: Aug 28, 2023
• Online Publication Date: Dec 28, 2023
• Publication Date: 2023-12
• Deposit Date: Jan 5, 2024
• Publicly Available Date: Jan 5, 2024
• Journal: Journal of Biomedical Optics
• Print ISSN: 1083-3668
• Electronic ISSN: 1560-2281
• Publisher: Society of Photo-optical Instrumentation Engineers
• Peer Reviewed: Peer Reviewed
• Volume: 28
• Issue: 12
• Article Number: 126007
• DOI: https://doi.org/10.1117/1.JBO.28.12.126007%5D
• Keywords: Standards; phantoms; non-linear imaging; hydrogel; depth imaging; axial scaling
• Public URL: https://nottingham-repository.worktribe.com/output/29271391