Heating pattern of helical microwave intracavitary oesophageal applicator
- 1 January 1991
- journal article
- research article
- Published by Informa UK Limited in International Journal of Hyperthermia
- Vol. 7 (4), 577-586
- https://doi.org/10.3109/02656739109034970
Abstract
Helical microwave intracavitary oesophageal (HMIO) applicators were designed to operate at frequencies of 433 MHz and 915 MHz. Heating patterns were studied within muscle-equivalent phantom by thermographic camera and fibreoptic thermometers. The results showed that frequency significantly influenced the microwave heating pattern. The 433 MHz applicator had a single power deposition region, the longitudinal specific absorption rate (SAR) distribution appeared to be nearly even, and the maximum SAR value occurred close to the centre of the active length of the applicator. The 915 MHz applicator had two power deposition regions, the peak SAR values occurred at about 1/4 and 3/4 of the active length respectively, The radial SAR distribution suggested that there is no obvious difference between the 433 MHz and 915 MHz applicators in that the average radial penetration of 50% surface SAR (RP50) was about 0.65 cm. It was also shown that power deposition was axially symmetric for both 433 MHz and 915 MHz HMIO applicators. It is shown that better impedance matching is more important for intracavitary hyperthermia than for external hyperthermia. Choosing HMIO applicators in clinical practice is also discussed.Keywords
This publication has 13 references indexed in Scilit:
- A technique for combining microwave hyperthermia with intraluminal brachytherapy of the oesophagusInternational Journal of Hyperthermia, 1989
- Microwave applicator for transurethral hyperthermia of benign prostatic hyperplasiaInternational Journal of Hyperthermia, 1989
- Design and thermometry of an intracavitary microwave applicator suitable for treatment of some vaginal and rectal cancersInternational Journal of Radiation Oncology*Biology*Physics, 1984
- Preoperative hyperthermo-chemo-radiotherapy effective for carcinoma of the esophagusJournal of Surgical Oncology, 1984
- Formulas for preparing phantom muscle tissue at various radiofrequenciesBioelectromagnetics, 1984
- Error Sources Affecting Thermocouple Thermometry in RF Electromagnetic FieldsThe Journal of Microwave Power, 1982
- A comparative heating‐pattern study of direct‐contact applicators in microwave diathermyRadio Science, 1977
- Increased Cures Using Fractionated Exposures of X Irradiation and Hyperthermia in the Local Treatment of the Ridgway Osteogenic Sarcoma in MiceRadiology, 1974
- Analyses of Electromagnetic Fields Induced in Biological Tissues by Thermographic Studies on Equivalent Phantom ModelsIEEE Transactions on Microwave Theory and Techniques, 1971