Abstract: A hyperthermia applicator/MRI probe assembly for hyperthermia treatment of a subject. The assembly includes a hyperthermia applicator for heating target regions of a subject and a MRI probe which is utilized to monitor temperatures within the heating region. The hyperthermia applicator and MRI probe are coupled to a control system which receives information from the MRI probe and utilizes the information to control the hyperthermia applicator so as to maintain constant, desired temperatures within the heating region. The hyperthermia applicator/MRI probe assembly of the present invention allows for temperature control within about 0.5.degree. C.

Abstract: A method of determining and imaging the temperature or temperature change of a liquid or solid object by NMR placing the object in a magnetic field B.sub.o at a temperature T.sub.o.sup.i, subjecting the object or a limited volume thereof to a first series of NMR imaging sequences to obtain first numerical values or images of molecular diffusion coefficients D.sub.o for individual points of the object or the limited volume thereof and recording the first series of images, maintaining the object or limited volume thereof at a temperature T.sup.i or waiting for a spontaneous change to the temperature, subjecting the object to a second series of magnetic resonance imaging sequences to obtain second numerical values or images of molecular diffusion coefficients D.sup.i for the same points of the object or the limited volume thereof and recording the second series of images, comparing point-by point the values or images of the diffusion coefficients D.sub.o.sup.