Journal article
Defining the heating characteristics of ferromagnetic implants using calorimetry
Journal of biomedical materials research, Vol.53(6), pp.791-798
2000
DOI: 10.1002/1097-4636(2000)53:6<791::AID-JBM21>3.0.CO;2-A
PMID: 11074438
Abstract
The induction heating of small, cylindrical ferromagnetic implants for localized tumors is currently under investigation. These thermal rods are implanted within a lesion in 1 cm(2) arrays and subsequently exposed to an externally applied alternating magnetic field. Implants absorb energy from the field and transfer it as heat to the surrounding tissue. To achieve a uniform temperature rise throughout the tissue volume and to account for any field-rod misalignment, 400 mW of power per implant is used as the design specification. The temperature to necrose cells must be greater than 46 degrees C. A calorimeter was constructed to confirm that the rod power output specification is satisfied at temperatures adequate for inducing cell death. The rods were designed to undergo a ferromagnetic to paramagnetic transition at temperatures of 55 degrees C, 60 degrees C, 65 degrees C, and 70 degrees C; this transition produces rods that are temperature self-regulating. Calorimetric results demonstrated that 55 degrees C, 60 degrees C, 65 degrees C, and 70 degrees C rods provided 400 mW at 47-51 degrees C, 51-53.5 degrees C, 57 degrees C, and 62.5-63.5 degrees C, respectively. Thermal rods provide sufficient power output at the temperatures necessary to cause thermal ablation of tumors. The higher-temperature rods give a greater margin to ensure that necrotizing temperatures can be achieved throughout the rod array even with minor misalignment.
Details
- Title: Subtitle
- Defining the heating characteristics of ferromagnetic implants using calorimetry
- Creators
- Jason A CASE - Department of Biomedical Engineering, University of Iowa, IA City, Iowa 52242, United StatesRobert D TUCKER - Department of Pathology, University of Iowa, Iowa City, Iowa 52242, United StatesJoon B PARK - Department of Biomedical Engineering, University of Iowa, IA City, Iowa 52242, United States
- Resource Type
- Journal article
- Publication Details
- Journal of biomedical materials research, Vol.53(6), pp.791-798
- Publisher
- John Wiley & Sons; New York, NY
- DOI
- 10.1002/1097-4636(2000)53:6<791::AID-JBM21>3.0.CO;2-A
- PMID
- 11074438
- ISSN
- 0021-9304
- eISSN
- 1097-4636
- Language
- English
- Date published
- 2000
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Pathology
- Record Identifier
- 9984047638402771
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