Blood flow changes resulting from laser heating measured using dynamic contrast-enhanced computed tomography

摘要

Abstract: The measurement of blood flow is important to understanding the physiological effects of heating on tissue. The primary effect of thermal therapies on solid tumors is the collapse of the blood vessels supplying the tumor, resulting in a thermal lesion due to the cessation of blood flow. We investigated the effect of heating on VX2 tumors implanted in the rabbit thigh, over the course of a one-hour treatment. A method of measuring the blood flow over an entire tissue slice using dynamic contrast-enhanced CT was developed. The distribution of the blood flow values was displayed as a single image in which a spectrum of pseudo-colors was used to encode blood flow values. This blood flow map provides both a visual and quantitative means of assessing blood flow changes and hence the tissue damage over time. From the blood flow maps we defined thermal lesions as tissue regions which had blood flow in the range of 0 - 2 ml/min/100g. Using this definition, the ratio of the thermal lesion area from pre-treatment to 60 minutes post-treatment, increased by a factor of 6, whereas the same ratios for the normal and viable tumor tissue remained essentially constant. !13