Journal ArticleDOI
Usable Frequencies in Hyperthermia with Thermal Seeds
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Temperature distributions are computed for tissue models assumed to be heated by constant power seeds, and from that, the heating power which the implants have to produce to achieve clinically acceptable temperatures in the tumor are obtained.Abstract:
Temperature distributions are computed for tissue models assumed to be heated by constant power seeds, and from that, the heating power which the implants have to produce to achieve clinically acceptable temperatures in the tumor are obtained. Calculations of the heat produced by thermal seeds exposed to an electromagnetic induction field showed it to be strongly dependent on the permeability of the material, on the field frequency, on the seed diameter, and on the orientation of the implants with respect to the field. It is recommended that, other parameters permitting, the implants be oriented parallel to the induction field and that the field frequency be approximately 200 kHz or lower. Under these conditions, implants with diameters as small as 0.25 mm produce sufflcient heat for any clinical application without undue heating by eddy currents flowing within the patient. The use of frequencies above the recommended range puts certain restrictions on the implant geometry and on the magnetic properties of their material. Needles oriented perpendicular to the field produce enough heat to reach therapeutic temperatures only within a narrow range of parameters.read more
Citations
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References
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Journal ArticleDOI
Tumor eradication by radiofrequency therapy. Responses in 21 patients.
TL;DR: Radiofrequency therapy produced tissue necrosis or substantial regression of cancer in 21 patients and elevated the temperatures of animal and human cancers by 5 to 9.5 C above that of healthy tissue.
Journal ArticleDOI
Magnetic Induction Heating of Ferromagnetic Implants for Inducing Localized Hyperthermia in Deep-Seated Tumors
TL;DR: It is demonstrated that it is possible to raise an implanted volume to therapeutic temperatures safely, in less than 10 min, with little increase in temperature outside the array boundaries.
Journal ArticleDOI
Treatment of superficial human neoplasms by local hyperthermia induced by ultrasound
TL;DR: It is concluded that superficial tumors can be safely and effectively heated by ultrasound, although it is stressed that, because of the short follow‐up time and, because most responses were partial, it is likely that the effects noted were transitory.
Journal ArticleDOI
Observations on the Use of Ferromagnetic Implants for Inducing Hyperthermia
Paul R. Stauffer,Thomas C. Cetas,Anne M. Fletcher,Donald W. Deyoung,Mark W. Dewhirst,James R. Oleson,Robert B. Roemer +6 more
TL;DR: Magnetic induction heating of ferromagnetic implants can be used to produce highly localized hyperthermia in deep seated tumors and several in vivo animal studies are presented to illustrate the use of the technique for treating tumors in pelvis, thorax, oral-pharynx, and brain.
Journal ArticleDOI
Tumor Eradication by Radiofrequency Therapy
TL;DR: One doubts the results achieved by the authors to be totally related to tumor blood flow, as certain problems with heat not described in the report published in the Journal are highlighted.