Water vaporization from heated tissue: an in vitro study by differential scanning calorimetry.

BACKGROUND AND OBJECTIVE

The heat balance equation is central to modeling laser vaporization of tissue. Because about 70% of tissue is water, energy loss due to water vaporization becomes an important consideration in modeling. In this study, the rate and pattern of water vaporization from various animal tissues studied by differential scanning calorimetry (DSC) are reported.

STUDY DESIGN/MATERIALS AND METHODS: DSC thermograms of fresh muscle, liver, and kidney tissues were made at heating rates of 2 degrees C/min, 5 degrees C/min, and 10 degrees C/min in the temperature range of 30-150 degrees C. Thermograms of vacuum-dried muscle sample were also made to establish that the endotherms obtained were essentially due to the water in the tissue.

RESULTS AND CONCLUSION

Two broad peaks-one below and the other above 100 degrees C-are seen in all the endotherms. The peaks are attributed to the structural and compositional features of tissue and tissue water. The two-stage vaporization pattern has importance in modeling tissue heating by a continuous-wave Nd:YAG laser.