The modification of specific absorption rates in interstitial microwave hyperthermia via tissue-equivalent material bolus
Autor: | Srinath Sundararaman, R.C. Samaratunga, Bernard S. Aron, Alvis E. Foster, Kevin P. Redmond, R.A. Legorreta, G. Cooper Lewis, David L. Denman, Angela M. Born, James G. Kereiakes, Howard R. Elson |
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Rok vydání: | 1990 |
Předmět: |
Male
Parabolic antenna Cancer Research medicine.medical_specialty Imaging phantom Dogs medicine Animals Humans Radiology Nuclear Medicine and imaging Dog Diseases Laryngeal Neoplasms Melanoma Aged Radiation business.industry Specific absorption rate Hyperthermia Induced Surgery Models Structural Tissue equivalent Oncology Head and Neck Neoplasms Carcinoma Squamous Cell Female Mouth Neoplasms Microwave hyperthermia Coaxial business Bolus (radiation therapy) Microwave Biomedical engineering |
Zdroj: | International Journal of Radiation Oncology*Biology*Physics. 19:677-685 |
ISSN: | 0360-3016 |
Popis: | Patterns of specific absorption rates generated by interstitial, microwave antenna arrays must be experimentally ascertained and quantified to facilitate their clinical incorporation. Phantom studies involved the use of four single-gap, coaxial antennas oriented in a 2 cm square array. These dipoles were driven in phase by a microwave generator at a frequency of 915 MHz. The inherent limitations in modifying the specific absorption rate patterns were addressed with the addition of bolus to the phantom. These additions of Guy's muscle tissue-equivalent material were made either proximal or distal to the phantom proper. Experiments conducted in the presence and absence of tissue-equivalent material bolus showed the ability to achieve broader bands of 50% power deposition in certain bolus conditions. These heating patterns were sufficiently reproducible and predictable to warrant clinical application of the bolus addition. A through-and-through method of catheter implantation allowed for bolus addition when deemed necessary. Treatments with veterinary and human patients using the bolus method to modify heating patterns yielded augmented patterns of power deposition. The effective length of the antennas that would radiate efficiently was essentially broadened via introduction of a microwave-interacting medium. As a result of the tissue equivalent material's ability to absorb microwave power, it was necessary to interpose minimally-interactive styrofoam spacers to limit heat transfer effects at the tissue-bolus interfaces. |
Databáze: | OpenAIRE |
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