We have developed magnetic fine particles for local heating technique for microwave hyperthermia. The aqueous dispersion of iron (II) iron (III) oxide fine particles was mixed with the aqueous gelatin solution at pH 5.0, which yielded the dispersion of iron (II) iron (III) oxide fine particles protected with gelatin (Gel-Mag fine particles) as magnetic fine particles. Gel-Mag fine particles were stable in physiological saline solution. Dispersion stability of Gel-Mag fine particles and the amount of gelatin adsorbed on iron (II) iron (III) oxide fine particles were measured. Larger amount of adsorbed gelatin resulted in larger dispersion stability of Gel-Mag fine particles.
When the dispersion of Gel-Mag fine particles was made to flow into polyvinylchloride tube located in the electrically muscle-equivalent agar phantom model, the accumulation of Gel-Mag fine particles was observed on the inner wall of the tube under the direct magnetic field. The 430 MHz-microwave (input power, 5 W) was irradiated for 5 min with a wave-guide applicator to the phantom model with the orientation of the electric field of the microwave in the same direction as that of the direct magnetic field. In the presence of the accumulated Gel-Mag fine particles at 10 mm from the aperture of the applicator, temperature elevation was 175% to that in the absence of Gel-Mag fine particles. This result showed that absorbance of microwave in the accumulated Gel-Mag fine particles caused the temperature elevation in the phantom model. It has been concluded that the Gel-Mag fine particles are useful materials for microwave heating.

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The problem with the capacitive-type heating method is the difficulty in supplying sufficient e-m energy to the deep portion of a body, because the subcutaneous fat layer is heated excessively. However, it would be partly due to unoptimized heating condition. The optimization of parameters in capacitive-type heating will fully realize its potential ability in the clinical use. To optimize the heating conditions, RF current distributions and SAR distributions in an elliptical shaped phantom, which was surrounded with a pair of overlay boli and a pair of boli on them, were calculated using the 3-D electromagnetic CAD software, MAFIA (Maxwell's equations by the Finite- Integration-Algorithm). Calculations were performed using various values of the parameters.
The calculated results with the optimized parameters showed a 33% increase of e-m energy in the deep portion of a body when compared with the conventional heating conditions.

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Unwanted temperature rise at muscle-bone interface has been one of the major problems during ultrasound hyperthermia treatment. In this study, we examined the alteration of temperature distribution caused by the existance of this interface from both computer calculation and model experiment. We especially took notice of the effect due to the incident angle of the ultrasonic wave.
It has been said that this heat generation at the surface has a close relationship with the beam's incident angle. Ultrasound penetrates inside of a bone as both copmressional waves and shear waves. And the transmission factors of these two waves differ in great deal with the alteration of the incident angle.

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As a part of a study on the non-thermal effects of magnetic or electromagnetic field on the living body, an influence of alternating magnetic field (AMF) on serotonin (5-HT) metabolism in humans was investigated. Using 12 commercial AMF generators of 50 Hz, 0.08 T (800gauss) in magnetic intensity of coil surface, a whole-body AMF stimulation was applied to subjects 30 minutes a day for 3 consecutive days, and the peripheral blood levels of 5-Ht and its metabolite, 5-HIAA, were measured. The AMF generator used provides little capacity to electromagnetically heat the body, thus the AMF stimulation has no heating effect enough to kill cancer cells in hyperthermia. The actual intensity of the AMF to which the human body was exposed was 0.5 to 7 mT (5 to 70 gauss). Blood was collected three times; before magnetic stimulation, 30 minutes after the first stimulation and after 3 days of stimulation. Body temperature was measured at the armpit at the same time. 5-HT in whole blood (n = 13) was significantly lowered by magnetic stimulation for 30 minutes (p <0.05) and markedly lowered by the stimulation for 3 days (p <0.001). The Plasma level of 5-HIAA (n=6) was not significantly affected by 30 minutes of magnetic stimulation, but was significantly elevated after stimulation for 3 days (p <0.01). No changes in body temperature at the armpit were observed. These results clearly demonstrate that the whole-body AMF stimulation affected 5-HT, one of vascular effectors, without mediation in thermal processes. The reduction in the blood level of 5-HT due to the AMF appears to be attributable mainly to inhibition of 5-HT synthesis or suppression of its release by the entero-chromaffin cells (EC cells) in the gastrointestinal tract. This non-thermal effect of AMF might be useful for hyperthermic therapy.

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The ¹H-MR spectra of plasma obtained from two patients under treatment with radiohyperthermochemotherapy (RHC) for malignant bone and soft tissue tumors were studied and assessed for treatment efficacy. High lactate peaks were obtained, similar to those already reported in other malignant tumors. Changes in the area of lactate peaks reflected treatment effect in the two cases reported. The lactate peaks showed a time-dependent decline in case 1 in which RHC was successful. In contrast the lactate peaks did not show change in case 2, in which RHC was not effective. To our knowledge, this is the first report of its kind in the orthopedic field.
There have been no useful serum markers for malignant tumors in the orthopedic field. The ¹H-MRS lactate peaks could contribute to assessment of treatment course in bone and soft tissue tumors.

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