ESR has some applications in medicine focusing of endogenous paramagnetic species in the body, as well as exogenous spin probes. spinflex tools can bring the potential of ESR to explore topics such as:

publications employing spinflex products

Compact electron spin resonance skin oximeter: Properties and initial clinical results

(Magnetic Resonance in Medicine, 85 (2021), 2915)

Purpose: Skin oxygen level is of significance for the diagnosis and treatment of many clinical problems, such as chronic wounds and diabetic foot ulcers. Furthermore, skin oxygen levels can be correlated to arterial oxygen partial pressure, thereby revealing potentially dangerous conditions such as hyperoxia (too much oxygen), which may occur in ventilated neonates. Traditionally, skin oxygen levels are measured using electrochemical methods and, more recently, also by fluorescence lifetime techniques. These approaches suffer from several drawbacks, rendering them suboptimal. The purpose of this work is to develop an electron spin resonance (ESR) ‐based method for monitoring oxygen partial pressure (pO2) in skin tissue.

Methods: A compact sensor for pulsed ESR is designed and constructed. Our ESR‐based method makes use of a unique exogenous paramagnetic spin probe that is placed on the skin in a special partially sealed sticker, and subsequently measuring its signal with the compact pulsed ESR sensor that includes a miniature magnet and a small S‐band (~2.3 GHz) microwave resonator. The inverse of the spin‐spin relaxation time (1/T2) measured by ESR is shown to be linearly correlated with pO2 levels.

Results: The sensor and its matching sticker were tested both in vitro and in vivo (with human subjects). Measured skin pO2 levels reached equilibrium after ~2‐3 h and were found to be comparable to those measured by continuous‐wave (CW) ESR using a large electromagnet.

Conclusions: A compact pulsed ESR sensor with a matching paramagnetic sticker can be used for pO2 monitoring of the skin tissue, similar to large bulky CW ESR systems.

A magnetic resonance probehead for evaluating the level of ionizing radiation absorbed in human teeth

(Health Physics, 108, (2015), 326)

A miniature electron spin resonance (ESR) probehead that includes a static field source and a microwave resonator for in vivo measurement of paramagnetic defects in tooth enamel was developed. These defects are known to be a good marker for quantifying the ionizing radiation dose absorbed in teeth. The probehead has a typical length of just 30 mm and total weight of 220 g. The patient “bites” into the probehead while the measurement procedure is being carried out. The probehead operates in pulsed mode at a frequency of ∼11.2 GHz and supplies a static magnetic field of ∼400 mT. A detailed design of the probehead is provided together with its specifications in terms of measurement volume and signal-to-noise ratio for a typical sample. A specially developed simulation program was used to predict the spatial distribution of the acquired signal under conditions of grossly inhomogeneous static and RF fields. Experimental results with irradiated incisor teeth validated the probehead’s sensitivity, being able to detect signals in tooth irradiated by only 2 Gy. Subject to additional improvements and tests, this type of probehead can potentially have significant clinical applications ranging from mass triage following major nuclear events to routine occupational evaluation of ionizing radiation absorbed over long periods of time.

Additional Publications

Electron spin resonance microscopic imaging of oxygen concentration in cancer spheroids

Authors name:
Mada Hashem, Michal Weiler-Sagie

Journal of Magnetic Resonance 256, (2015), 77-85

A Magnetic Resonance Probehead for Evaluating the Level of Ionizing Radiation Absorbed in Human Teeth

Authors name:
Woflson, Helen, Ahmad, Rizwan

Health Physics 108 (2015), 326-335

Induction-detection electron spin resonance with spin sensitivity of a few tens of spins

Authors name:
Yaron Artzi, Ygal Twig

Appl. Phys. Lett. 106, (2015), 084104