PURPOSE To elucidate the basic thermophysical properties at low temperatures of lipiodol, which is used as a marker by transarterial injection before CT-guided cryoablation for solid tumors, by fundamental experiments with pure lipiodol phantom. MATERIALS AND METHODS The freezing point of lipiodol was measured using differential scanning calorimeter (DSC) by detecting differences in the heating rate during heating from - 30 °C. Freezing experiments were conducted using pure lipiodol and a tissue phantom, which were prepared in an acrylic container at 37 °C. The growth of the frozen region was observed for 10 min. Temperatures were monitored at the cryoprobe surface and designated positions around the cryoprobe. RESULTS The DSC experiment showed that freezing was observed between - 5 and - 30 °C, which indicated that the freezing point was approximately - 5 °C. Freezing experiments revealed that the diameter of frozen region in the lipiodol was smaller than that in the tissue phantom (5 mm vs 24 mm) after 10-min freezing. The temperature at the probe surface was - 130 °C in lipiodol, which was 25 °C lower than that in the tissue phantom. There was a larger temperature gradient near the cryoprobe in lipiodol due to lower thermal conductivity. CONCLUSIONS The present results suggest that an extremely high concentration of lipiodol (close to pure lipiodol) potentially reduces frozen region because of its lower freezing point and smaller thermal conductivity. However, since lipiodol concentrations in clinical cases differ from the current model, further studies using models that are close to clinical conditions are required. LEVEL OF EVIDENCE No level of evidence, laboratory investigation.

中文翻译：

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与冷冻消融相关的碘油热物理性质的基本评估：使用碘油幻影的冷冻实验。

目的通过纯脂质体模的基础实验，阐明脂质体在低温下的基本热物理性质，该物质在CT引导的冷冻消融之前通过经动脉注射用作实体瘤的标记物。材料与方法使用差示扫描量热仪（DSC）通过检测从-30°C加热期间的加热速率差异来测量碘油的凝固点。使用纯碘油和组织体模进行冷冻实验，它们是在37°C的丙烯酸容器中制备的。观察冷冻区域的生长10分钟。在冷冻探针表面和冷冻探针周围的指定位置处监测温度。结果DSC实验表明，在-5至-30°C之间观察到冻结，这表明冰点约为-5°C。冷冻实验表明，冷冻10分钟后，碘油中冷冻区域的直径小于组织体模中的冷冻区域的直径（5毫米对24毫米）。碘油中探针表面的温度为-130°C，比组织体模中的温度低25°C。由于较低的热导率，碘油中的冷冻探针附近存在较大的温度梯度。结论目前的结果表明，由于其较低的凝固点和较小的热导率，极高浓度的碘油（接近纯碘油）可能会减少冷冻区域。但是，由于临床病例中的碘油浓度与当前模型不同，因此需要使用接近临床条件的模型进行进一步的研究。