SU-F-E-05: Determination of Breakeven Points of in Vitro Meats and in Vivo Mice Based On Tissue Temperature Enhancement Pattern.

PURPOSE: To determine the breakeven points in fresh commercial meat and in vivo mice using the tissue temperature enhancement pattern.

METHODS: A 1 cm length and 0.1 cm diameter gold rod were implanted in fresh chicken breast, beef, fish, in vivo Mus Musculus white mice (medial dorsal region) and insonated with ultrasound. The temperature enhancement of gold rods was measured with a needle type thermistor over a temperature range from 35-50 oC. From these results the breakeven points were determined by plotting the gold rod temperature versus ultrasound exposure time and determining the interception point of two curves fitted by a linear regression of thermal response above and below 43 °C.

RESULTS: The linear correlation coefficients for all fitted curves lie within 0.97 and 0.99. The breakeven points were found to be the same for all kinds of fresh meat (fish = 42.1 ±1.1, chicken breast = 42.3 ±0.9, beef = 42.6 ±0.8) and in vivo Mus Musculus white mice (43.3 ±0.6). These temperatures agree with the standardized value (e.g. equivalent minutes at 43 °C) for comparison of thermal treatments (Proc. SPIE Int. Soc. Opt. Eng. 2003 June 2; 4954: 37).

CONCLUSION: The interception of the thermal response curves above and below 43 °C may be used as a fast method and useful dosimetric tool in clinical research.