  Nanomagnetic hyperthermia (NMH) is intensively studied with the prospect of
cancer therapy. A major challenge is to determine the dissipated power during
in vivo conditions and conventional methods are either invasive or inaccurate.
We present a non-calorimetric method which yields the heat absorbed during
hyperthermia: it is based on accurately measuring the quality factor change of
a resonant radio frequency circuit which is employed for the irradiation. The
approach provides the absorbed power in real-time, without the need to monitor
the sample temperature as a function of time. As such, it is free from the
problems caused by the non-adiabatic heating conditions of the usual
calorimetry. We validate the method by comparing the dissipated power with a
conventional calorimetric measurement. We present the validation for two types
of resonators with very different filling factors: a solenoid and a so-called
birdcage coil. The latter is a volume coil, which is generally used in magnetic
resonance imaging (MRI) under in vivo condition. The presented method therefore
allows to effectively combine MRI and thermotherapy and is thus readily
adaptable to existing imaging hardware.
