Towards a mechanical MPI scanner based on atomic magnetometry

TL;DR

This paper presents progress on developing an atomic magnetometer-based low-frequency MPI scanner that avoids SAR and PNS issues, demonstrating high sensitivity and detailed coil design for improved spatial resolution.

Contribution

The work introduces a pump-probe atomic magnetometer scheme capable of tolerating strong gradients, with detailed coil design for FFL operation in MPI.

Findings

AM sensitivity in the one-digit pT/Hz^(1/2) range

Tolerance to mT/m magnetic field gradients

Feasible field of view and resolution estimates

Abstract

We report on our progress in the development of an atomic magnetometer (AM) based low-frequency magnetic particle imaging (MPI) scanner, expected to be free from Specific Absorption Rate (SAR) and Peripheral Nerve Stimulation (PNS) constraints. We address major challenges in coil and sensor design due to specific AM properties. Compared to our previous work we have changed the AM's mode of operation towards its implementation for detecting weak magnetic nanoparticles (MNP) response fields in the presence of nearby-located strong drive/selection fields. We demonstrate that a pump-probe AM scheme in a buffer gas filled alkali vapour cell can tolerate mT/m gradients while maintaining a sensitivity in the one-digit pT/Hz^(1/2) range over a bandwidth from DC to several kHz. We give a detailed description of the drive/selection coils' geometry and their hardware implementations that provides a field-free-line (FFL) operation, compatible with a best performance AM operation. We estimate the achievable field of view and spatial resolution of the scanner as well as its sensitivity, assuming mechanical scanning of a Resovist sample through the field-free point/line.