Magnetic resonance imaging of single domain nanoparticles

A method of gathering information about an object, the object comprising single domain particles which comprise iron oxide having at least a predetermined longitudinal relaxation time, the method comprising:

• detecting pulsed electron paramagnetic resonance (EPR) of the single domain particles upon interaction of the object with a static magnetic field of less than 0.1 Tesla and with RF energy transmitted as pulses of electromagnetic radiation for the object at a frequency to generate EPR of the single domain particles, the detecting being detecting in the form of an image of the object, the EPR detecting comprising identifying echo pulses of the transmitted pulses, the echo pulses being generated as the transmitted pulses are reflected by the single domain particles.

A receiver for detecting single domain particles comprising iron oxide, the single domain particles having a diameter in the range of 5 nm to 80 nm and having an electron paramagnetic response to an applied static magnetic field of less than 0.1 Tesla for the object and an applied RF energy transmitted as pulses of electromagnetic radiation for the object at a frequency to generate electron paramagnetic resonance (EPR) of the single domain particles, the receiver comprising:

• a detector configured to detect a response of the single domain particles comprising iron oxide in reply to the applied RF energy, the detecting being detecting in the form of an image, the detecting comprising identifying echo pulses of the transmitted pulses, the echo pulses being generated as the transmitted pulses are reflected by the single domain particles;
• and
• a discriminator configured to identify in the echo pulses the electron paramagnetic response of the single domain particles.