Conductive interstitial thermal therapy device for surgical margin ablation: in vivo verification of a theoretical model.
OBJECTIVE
To demonstrate the efficacy and predictability of a new conductive interstitial thermal therapy (CITT) device to ablate surgical margins.


METHODS
The temperature distributions during thermal ablation of CITT were calculated with finite element modelling in a geometrical representation of perfused tissue. The depth of ablation was derived using the Arrhenius and the Sapareto and Dewey (S&D) models for the temperature range of 90 to 150 degrees C. The female pig animal model was used to test the validity of the mathematical model. Breast tissues were ablated to temperatures in the range of 79-170 degrees C, in vivo. Triphenyltetrazolium chloride viability stain was used to delineate viable tissue from ablated regions and the ablation depths were measured using digital imaging.


RESULTS
The calculations suggest that the CITT can be used to ablate perfused tissues to a 10-15 mm width within 20 minutes. The measured and calculated depths of ablation were statistically equivalent (99% confidence intervals) within +/- 1mm at 170 degrees C. At lower temperatures the equivalence between the model and the observations was within +/- 2 mm.


CONCLUSIONS
The CITT device can reliably and uniformly ablate a 10-15 mm wide region of soft tissue. Thus, it can be used to secure negative margins following the resection of a primary tumor, which could impede local recurrences in the treatment of local diseases such as early staged, non-metastatic, breast cancer.
Shafirstein
Gal
G
Department of Otolaryngology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA. Shafirsteingal@uams.edu
Novák
Petr
P
Moros
Eduardo G
EG
Siegel
Eric
E
Hennings
Leah
L
Kaufmann
Yihong
Y
Ferguson
Scott
S
Myhill
Jeffrey
J
Swaney
Mark
M
Spring
Paul
P
D000818:Animals; D001943:Breast Neoplasms / Q000601:surgery*; D002425:Cautery / Q000295:instrumentation*; D004195:Disease Models, Animal; D004867:Equipment Design; D005260:Female; D006979:Hyperthermia, Induced / Q000295:instrumentation*; D008321:Mammary Glands, Animal / Q000601:surgery*; D015412:Mastectomy, Segmental / Q000379:methods; D008954:Models, Biological; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D018365:Neoplasm, Residual / Q000601:surgery; D034421:Sus scrofa; D013778:Tetrazolium Salts; D013814:Thermal Conductivity
D013778:Tetrazolium Salts; C009591:triphenyltetrazolium