  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.
