A technique for the production of a high amplitude, high frequency, concentrated magnetic field for use in hyperthermia applications
Date
2013-02-06
Authors
Sessel, Gareth Kevin
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Abstract
Cancer of the liver is a common disease with a relatively poor prognosis. Hyperthermia is an
exciting treatment that is under investigation. One modality of hyperthermia therapy makes use of
an external magnetic field to produce losses in magnetic particles that have been supplied to the
tumour. The losses result in the heating of the tumour cells thereby causing cell destruction. There
exists a limit in the product of magnetic field intensity and frequency, above which eddy currents
reach levels capable of causing thermal damage in healthy tissue. This limit is well documented in
the literature and, due to the seriousness of the disease, can be increased to 5 x 109 A/ms.
The magnetic field used by most researchers is produced by simple coils. Using these simple coils,
it is very difficult to produce sufficient heating throughout the tumour cells without exceeding the
safety limit in healthy tissue. This research provides a machine that is capable of producing a
magnetic field of sufficient energy to cause therapeutic heating within the tumour region whilst
remaining within the safety limit elsewhere. A design methodology for this machine is
demonstrated. A prototype machine is built and tested in order to validate the design procedure. The
results from the prototype experiment are in good agreement with those predicted by the theory.
The idea of “focussing” a magnetic field in distances far smaller than the wavelength of the field is
a novel concept. This fundamentally new research has the potential to assist in the development of a
treatment for tumour sufferers.