In accordance with one aspect of this disclosure, there is provided a device for performing magnetic resonance relaxometry. The device comprises a radio-frequency spectrometer comprising at least one field-programmable gate array chip； a power amplifier electrically connected with the radio-frequency spectrometer and amplifying an electrical output of the radio-frequency spectrometer, thereby producing an amplified electrical signal comprising between about 0.1 Watts and about 10 Watts power； a duplexer configured to isolate the radio-frequency spectrometer from the amplified electrical signal during a receiving mode of the device； a radio-frequency detection probe configured to transmit radio-frequency electromagnetic radiation to excite nuclei under resonance during a transmission mode of the device, the radio-frequency detection probe comprising a detection coil comprising an inner diameter of less than about 1 millimeter； and at least one magnet supplying an external magnetic field to a detection region of the radio-frequency detection probe, the external magnetic field being less than about 3 Tesla.
