Tumor ablation at low frequencies for preferential tumor heating: Initial ex-vivo tissue studies

Schutt, David J.; Haemmerich, Dieter

doi:10.1109/iembs.2008.4649134

Cited by 4 publications

(5 citation statements)

References 8 publications

(16 reference statements)

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“…In addition, the data on electrical conductivity measured in this study may be valuable in mathematical models of cancer treatment protocols that utilize tissue heating, such as RF ablation or RF hyperthermia. Furthermore, the data presented here support recent studies that have suggested that ablating hepatic tumours at lower frequencies (∼20 kHz) than currently used (∼460 kHz) could preferentially heat tumour tissue and preserve surrounding normal tissue, due to the increased difference in electrical conductivity between normal and malignant tissues at those frequencies (figure 3) Wood 2006, Schutt andHaemmerich 2008).…”

Section: Discussionsupporting

confidence: 88%

“…We measured conductivity over the frequency range of 10 Hz to 1 MHz, including the standard RF ablation frequency (460 kHz). This frequency range was selected since this measurement system has been well characterized within this range (Tsai et al 2002a), and because the electrical conductivity of tumour and normal tissue at these frequencies is of current research interest Wood 2006, Schutt andHaemmerich 2008). Figure 2 shows a block diagram of the measurement system.…”

Section: Measurement Systemmentioning

confidence: 99%

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Ethanol Macrocluster Formation on Gold Substrate Modified with Mercapto Alcohol

Endo

Kurihara

2006

jjap

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We measured the ex vivo electrical conductivity of eight human metastatic liver tumours and six normal liver tissue samples from six patients using the four electrode method over the frequency range 10 Hz to 1 MHz. In addition, in a single patient we measured the electrical conductivity before and after the thermal ablation of normal and tumour tissue. The average conductivity of tumour tissue was significantly higher than normal tissue over the entire frequency range (from 4.11 versus 0.75 mS cm −1 at 10 Hz, to 5.33 versus 2.88 mS cm −1 at 1 MHz). We found no significant correlation between tumour size and measured electrical conductivity. While before ablation tumour tissue had considerably higher conductivity than normal tissue, the two had similar conductivity throughout the frequency range after ablation. Tumour tissue conductivity changed by +25% and −7% at 10 Hz and 1 MHz after ablation (0.23-0.29 at 10 Hz, and 0.43-0.40 at 1 MHz), while normal tissue conductivity increased by +270% and +10% at 10 Hz and 1 MHz (0.09-0.32 at 10 Hz and 0.37-0.41 at 1 MHz). These data can potentially be used to differentiate tumour from normal tissue diagnostically.

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Section: Discussionsupporting

confidence: 88%

Section: Measurement Systemmentioning

confidence: 99%

Ethanol Macrocluster Formation on Gold Substrate Modified with Mercapto Alcohol

Endo

Kurihara

2006

jjap

View full text Add to dashboard Cite

show abstract

“…We measured conductivity over the frequency range of 10 Hz to 1 MHz, including the standard RF ablation frequency (460 kHz). This frequency range was selected since this measurement system has been well characterized within this range (Tsai et al 2002a), and because the electrical conductivity of tumour and normal tissue at these frequencies is of current research interest (Haemmerich and Wood 2006, Schutt and Haemmerich 2008). Figure 2 shows a block diagram of the measurement system.…”

Section: Methodsmentioning

confidence: 99%

Electrical conductivity measurement of excised human metastatic liver tumours before and after thermal ablation

et al. 2009

Self Cite

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We measured the ex vivo electrical conductivity of eight human metastatic liver tumours and six normal liver tissue samples from six patients using the four electrode method over the frequency range 10 Hz to 1 MHz. In addition, in a single patient we measured the electrical conductivity before and after the thermal ablation of normal and tumour tissue. The average conductivity of tumour tissue was significantly higher than normal tissue over the entire frequency range (from 4.11 versus 0.75 mS cm −1 at 10 Hz, to 5.33 versus 2.88 mS cm −1 at 1 MHz). We found no significant correlation between tumour size and measured electrical conductivity. While before ablation tumour tissue had considerably higher conductivity than normal tissue, the two had similar conductivity throughout the frequency range after ablation. Tumour tissue conductivity changed by +25% and −7% at 10 Hz and 1 MHz after ablation (0.23−0.29 at 10 Hz, and 0.43−0.40 at 1 MHz), while normal tissue conductivity increased by +270% and +10% at 10 Hz and 1 MHz (0.09−0.32 at 10 Hz and 0.37−0.41 at 1 MHz). These data can potentially be used to differentiate tumour from normal tissue diagnostically.

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“…[19][20][21] During RFA, heat generated could be attenuated in tissues using a heat sink between 0.005 and 0.01 m around the vein. 22 More research is needed to understand the properties of conductance and energy transfer of 10 per cent agar, specifically to RFA. In addition, because each individual patient is different with respect to age, fat content, water percentage, nerve distribution, and muscle development, future development of new and complex materials with similar thermal conduction by using multiple layers to more accurately demonstrate heat dispersion in human subcutaneous fat, muscle, nerve, and skin is needed.…”

Section: Discussionmentioning

confidence: 99%

Radiofrequency Thermal Ablation Heat Energy Transfer in an Ex-Vivo Model

Thakur

Lavito

Grobner

et al. 2017

The American Surgeon™

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Little work has been done to consider the temperature changes and energy transfer that occur in the tissue outside the vein with ultrasound-guided vein ablation therapy. In this experiment, a ex-vivo model of the human calf was used to analyze heat transfer and energy degradation in tissue surrounding the vein during endovascular radiofrequency ablation (RFA). A clinical vein ablation protocol was used to determine the tissue temperature distribution in 10 per cent agar gel. Heat energy from the radiofrequency catheter was measured for 140 seconds at fixed points by four thermometer probes placed equidistant radially at 0.0025, 0.005, and 0.01 m away from the RFA catheter. The temperature rose 1.5°C at 0.0025 m, 0.6°C at 0.005 m, and 0.0°C at 0.01 m from the RFA catheter. There was a clinically insignificant heat transfer at the distances evaluated, 1.4 ± 0.2 J/s at 0.0025 m, 0.7 ± 0.3 J/s at 0.0050 m, and 0.3 ± 0.0 J/s at 0.01 m. Heat degradation occurred rapidly: 4.5 ± 0.5 J (at 0.0025 m), 4.0 ± 1.6 J (at 0.0050 m), and 3.9 ± 3.6 J (at 0.01 m). Tumescent anesthesia injected one centimeter around the vein would act as a heat sink to absorb the energy transferred outside the vein to minimize tissue and nerve damage and will help phlebologists strategize options for minimizing damage.

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Tumor ablation at low frequencies for preferential tumor heating: Initial ex-vivo tissue studies

Abstract: Tumor ablation at frequencies lower than currently used may preferentially heat tumor tissue, preserving normal tissue at the treatment site.

Cited by 4 publications

References 8 publications

Ethanol Macrocluster Formation on Gold Substrate Modified with Mercapto Alcohol

Ethanol Macrocluster Formation on Gold Substrate Modified with Mercapto Alcohol

Electrical conductivity measurement of excised human metastatic liver tumours before and after thermal ablation

Radiofrequency Thermal Ablation Heat Energy Transfer in an Ex-Vivo Model

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