Development of a 70 MHz unit for hyperthermia treatment of deep-seated breast tumors

Johannes Crezee, Geertjan van Tienhoven, Merel W. Kolff, Jan Sijbrands, Gerard van Stam, Sabine Oldenborg, Elisabeth D. Geijsen, Maarten C. C. M. Hulshof, Henny P. Kok

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A dedicated hyperthermia (HT) system was designed for tumors in intact breast extending beyond the heating depth of our superficial 434 MHz antennas, consisting of a treatment bed fitted with a 50 cm × 40 cm × 16 cm temperature controlled open water bolus. The patient lies in prone position with the breast immersed in the water positioned in front of a 34 cm × 20 cm 70 MHz waveguide operating in the TE10 mode. E-field patterns were measured in a tissue-mimicking phantom. HT was applied once a week with the 70 MHz applicator for six patients treated with thermoradiotherapy for deep lesions of recurrent breast cancer or melanoma. Two 14-sensor thermocouple thermometry probes were placed in catheters to monitor the invasive temperature. Results: Phantom measurements showed sufficient penetration depth up to 10 cm depth. The combination of 300-900 W antenna power and a water temperature of 42°C was well tolerated for the entire session of 1 h and resulted in good tumor temperatures with T90 = 39.8°C, T50 = 41.1°C, and T10 = 42.2°C. No toxicity or complaints were associated with the heating. A water mattress and other measures were needed to assure a comfortable position throughout the treatment. Conclusion: The 70 MHz breast applicator system performed well and tumor temperatures were good.
Original languageEnglish
Pages (from-to)1317-1324
Issue number6
Publication statusPublished - 2017

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