On the Applicability of the Thermal Dose Cumulative Equivalent Minutes Metric to the Denaturation of Bovine Serum Albumin in a Polyacrylamide Tissue Phantom
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, Oxfordshire, United Kingdom OX3 7DQ (United Kingdom)
Thermal dose has been proposed for various hyperthermic cancer treatment modalities as a measure of heat-induced tissue damage. However, the applicability of current thermal dose metrics to tissue is not well understood, particularly at the temperatures and rates of heating relevant to ablative cancer therapy using High-Intensity Focussed Ultrasound (HIFU). In this work, we assess whether the most widely employed thermal dose metric, Cumulative Equivalent Minutes (CEM), can adequately quantify heat-induced denaturation in a tissue-mimicking material (phantom) consisting of Bovine Serum Albumin (BSA) proteins embedded in a polyacrylamide matrix. The phantom is exposed to various temperature profiles and imaged under controlled lighting conditions against a black background as it denatures and becomes progressively more opaque. Under the assumption that the mean backscattered luminous intensity provides a good measure of the extent of BSA denaturation, we establish a relationship between the amount of thermal damage caused to the phantom, exposure time, and temperature. We demonstrate that, for monotonically increasing and bounded temperature profiles, the maximal degree to which the phantom can denature is dependent on the peak temperature it reaches, irrespective of exposure duration. We also show that when the CEM is computed using the commonly employed piecewise-constant approximation of the parameter R, the CEM values corresponding to the same degree of damage delivered using different temperature profiles do not agree well with each other in general.
- OSTI ID:
- 21293555
- Journal Information:
- AIP Conference Proceedings, Vol. 1113, Issue 1; Conference: 8. international symposium on therapeutic ultrasound, Minneapolis, MN (United States), 10-13 Sep 2008; Other Information: DOI: 10.1063/1.3131414; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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