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The multielectrode current‐source interstitial hyperthermia system
Author(s) -
van der Koijk John F.
Publication year - 1997
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.597965
Subject(s) - biomedical engineering , thermocouple , materials science , hyperthermia , electrode , temperature control , current source , temperature measurement , implant , current (fluid) , electrical engineering , surgery , chemistry , mechanical engineering , physics , composite material , medicine , meteorology , quantum mechanics , engineering
The multielectrode current‐source interstitial hyperthermia (MECS‐IHT) system uses metallic electrodes inserted into plastic catheters and connected to 27 MHz sources. The heat deposition (SAR) along the catheter track is controlled by using several independent electrodes in a single catheter. The MECS probes incorporate multi‐sensor thermocouple thermometry. The planning system contains modules for the calculation of the power deposition in tissue, heat transport calculation, incorporating discrete vasculature, electrode power control, analysis of temperature distributions, implant planning and the visualisation of temperature distributions and of the implant setup. The ideal current source approximation used in the treatment planning/SAR model is validated and it is shown that tissue inhomogeneities do not pose major electrical problems. The temperatures measured in the catheter can be used for power control during treatment. The temperature distributions during treatment were investigated using models of idealized anatomies with and without discrete vasculature. Even with high contrasts in electrical and thermal conductivity in the implant it remains possible to obtain satisfactory temperature distributions with the MECS system. Inhomogeneities in the implant volume lead to inferior temperature distributions if no longitudinal SAR control is available. The spatial SAR control of the MECS‐IHT system, combined with the temperature feedback, is essential for optimizing the temperature control. Treatments using the system are technically successful.