A Cylindrical Surface Dielectric Resonator with Substantially High Sensitivity for Deep-Tissue EPR Oximetry

IF 1.1 4区物理与天体物理 Q4 PHYSICS, ATOMIC, MOLECULAR & CHEMICAL

Applied Magnetic Resonance Pub Date : 2024-12-31 DOI:10.1007/s00723-024-01747-8

Sergey V. Petryakov, Maciej M. Kmiec, Ryan C. O’Connell, Conner S. Ubert, Victor B. Kassey, Philip E. Schaner, Periannan Kuppusamy

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引用次数: 0

Abstract

Electron paramagnetic resonance (EPR) has been established as a unique and reliable method for quantitative in vivo oximetry applicable to a variety of preclinical and clinical studies. A recent clinical study using EPR oximetry with OxyChip from our laboratory demonstrated the feasibility of tumor oxygen measurements in cancer patients (Schaner, et al. Front. Oncol. 2021). During this study, the need to improve oxygen measurement capability in tumors at depths greater than 10 mm became apparent. This prompted us to develop new designs of resonators (RF coils) with enhanced sensitivity for measuring deep-tissue oxygen levels. In this manuscript, we report the development of a new cylindrical surface dielectric resonator (c-SDR) designed with a ceramic dielectric material for substantially enhanced sensitivity and capability for deep-tissue oximetry. The c-SDR was constructed with a cylindrical dielectric material (ϕ 27.2 × 22.2 mm; ε = 160), 6-segmented coupling loop and copper shield to provide an active surface (aperture) of 25 mm with an operating frequency of 1.16 GHz (L-band) and an unloaded Q 600. The resonator could detect OxyChip (ϕ 0.6 × 5 mm) at a surface-to-sample depth of 50 mm in water or 30 mm in a tissue-emulating phantom with a signal-to-noise ratio of 5. Further evaluations of the c-SDR using OxyChip demonstrated its capability for oxygen measurements at depths of 27 mm for 1% oxygen and 15 mm for 5% oxygen in a tissue phantom. In conclusion, the new c-SDR is a significant upgrade to the currently used resonators for in vivo EPR oximetry including clinical oximetry.

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具有高灵敏度的圆柱形表面介电谐振器用于深层组织EPR氧饱和度测定

电子顺磁共振（EPR）已成为一种独特、可靠的体内血氧定量测定方法，适用于各种临床前和临床研究。最近的一项临床研究使用EPR血氧仪和我们实验室的OxyChip证明了在癌症患者中测量肿瘤氧的可行性（Schaner等）。前面。肿瘤防治杂志。2021)。在这项研究中，提高肿瘤深度大于10mm的氧气测量能力的必要性变得明显。这促使我们开发新的谐振器（RF线圈）设计，具有更高的灵敏度，用于测量深层组织氧水平。在这篇论文中，我们报告了一种新的圆柱形表面介质谐振器（c-SDR）的开发，该谐振器采用陶瓷介质材料设计，大大提高了深层组织氧饱和度的灵敏度和能力。c-SDR采用圆柱形介电材料(φ 27.2 × 22.2 mm；ε = 160)， 6段耦合环路和铜屏蔽，提供25 mm的有效表面（孔径），工作频率为1.16 GHz （l波段）和卸载Q 600。该谐振器可以在50毫米的水面对样品深度或30毫米的组织模拟模体中检测OxyChip (φ 0.6 × 5mm)，信噪比为5。使用OxyChip对c-SDR进行的进一步评估表明，它能够在27毫米深的组织模体中测量1%氧气和15毫米深的5%氧气。总之，新的c-SDR是对目前用于体内EPR血氧测定（包括临床血氧测定）的谐振器的重大升级。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Applied Magnetic Resonance 物理-光谱学

CiteScore

1.90

自引率

10.00%

发文量

审稿时长

2.3 months

期刊介绍： Applied Magnetic Resonance provides an international forum for the application of magnetic resonance in physics, chemistry, biology, medicine, geochemistry, ecology, engineering, and related fields. The contents include articles with a strong emphasis on new applications, and on new experimental methods. Additional features include book reviews and Letters to the Editor.