In vivo 300 MHz longitudinally detected ESR-CT imaging in the head of a rat treated with a nitroxide radical.

In vivo longitudinally detected ESR (LODESR)-CT system operating at 300 MHz was developed, based on the combination of a bridged loop-gap resonator and a pair of saddle-type pickup coils (STPCs). The sensitivity distribution of the STPCs was simulated on the basis of a magnetic dipole model. A LODESR-CT image of a phantom (a physiological saline solution of a nitroxide radical) was satisfactorily corrected by using the simulation result. LODESR-CT images of the head of a rats, in which nitroxide radical was injected intraperitonally, were also obtained through the correction in the same manner. This is the first in vivo CT (i.e. three-dimensional imaging) study with a 300 MHz ESR.