Novel Food-Safe Spin-Lattice Relaxation Time Calibration Samples for Use in Magnetic Resonance Sensor Development

Abstract

Magnetic Resonance (MR) sensors are an area of increasing interest for the measurement and monitoring of material properties. There are two relaxation times associated with samples that can be measured with MR sensors: The spin-lattice and spin-spin relaxations. When developing new sensors, it is desirable to have a series of standards by which instruments can be assessed. The standard calibration materials available typically comprise different concentrations of Nickel Sulphate which is carcinogenic and toxic. In this work we report the use of solutions containing full fat milk powder as a safe and inexpensive material that shortens the longitudinal relaxation time of water over a wide range of values. We demonstrate that concentrations in distilled water from 5% w/v to 64% w/v give T1 values from 1.7 s down to 469 ms respectively in a 1.5T clinical MRI, while within an MR sensor these times were from 1.6 s down to 431 ms. In addition, both systems have the same exponential coefficient (−0.022× concentration) that demonstrates the effectiveness of the NMR sensor in comparison to the clinical MRI.

A preliminary study of milk powder hydration using TEDSpiL continuous wave NMR

“…The variation in T x of solutions due to changes in the concentration of milk powder is demonstrated in Figure . Higher concentrations of milk powder in distilled water leads to an increase in viscosity due to the abundance of lactose, proteins, and fats, which is known to decrease spin–lattice relaxation times, reproducing the results of Almazrouei et al…”

Optical method for verification of homogeneity of phantoms for calibration of magnetic resonance

“…In order to do that, various calibration phantoms are created [1][2] -some of them are used to determine geometric accuracy, others to calibrate relaxation times and proton density. Manufacturing procedures of new phantoms for calibration of medical devices are still being developed [3][4][5][6][7][8]. Unfortunately, in the production process different heterogeneities may emerge, such as air bubbles or spatial differences in the composition.…”