Nabaei Malikeh, Karimi Mehrdad
Biomedical Engineering Department, Amirkabir University of Technology, 424 Hafez Ave, Tehran 15875-4413, Iran.
J Therm Biol. 2018 Oct;77:45-54. doi: 10.1016/j.jtherbio.2018.08.001. Epub 2018 Aug 7.
Cryosurgery is an efficient cancer treatment which can be used for non-invasive ablation of some internal tumors such as liver and prostate. Tumors are usually located near the large blood vessels and the heat convection may affect the progression of the ice ball. Hence it is necessary to predict the surgery procedure and its consequences earlier. In spite of the recent studies it is still unclear that which arteries will significantly affect the freezing treatment of tumors and which can be ignored. Therefore a numerical model of a spherical 3 cm diameter liver tumor, subjected to cryosurgery was developed. The specific thermophysical properties were applied to the tumor and healthy tissues in frozen and unfrozen states. A simplified Hepatic artery with different anatomical diameters was placed in different positions relative to the tumor and energy and momentum equations were solved. The temperature distribution and the shape of the resultant ice ball were discussed. The results showed that a 4 mm diameter artery in the vicinity of a tumor will increase the minimum temperature achieved at the tumor boundary by 12.5 °C and therefore significantly affects the cryosurgery outcome. This may cause insufficient freezing which leads to incomplete death of tumor cells, failure of the surgery and tumor regenesis. Eventually it was shown that injection of gold and FeO nanoparticles to the surrounding tissue of the artery can enhance the heat transfer and progression of the ice ball, making temperature distribution similar to the no vessel state. Development of computational models can provide the physicians an applicable tool which helps them recognize how efficient a treatment method will be for a specific case and design a suitable cryosurgery plan.
冷冻手术是一种有效的癌症治疗方法，可用于对某些内部肿瘤（如肝脏和前列腺肿瘤）进行非侵入性消融。肿瘤通常位于大血管附近，热对流可能会影响冰球的进展。因此，有必要尽早预测手术过程及其后果。尽管最近有研究，但仍不清楚哪些动脉会对肿瘤的冷冻治疗产生显著影响，哪些可以忽略。因此，建立了一个直径为3厘米的球形肝脏肿瘤冷冻手术的数值模型。将特定的热物理性质应用于处于冷冻和未冷冻状态的肿瘤及健康组织。将具有不同解剖直径的简化肝动脉放置在相对于肿瘤的不同位置，并求解能量和动量方程。讨论了温度分布和所得冰球的形状。结果表明，肿瘤附近直径为4毫米的动脉会使肿瘤边界处达到的最低温度升高12.5°C，因此会显著影响冷冻手术的结果。这可能导致冷冻不足，从而导致肿瘤细胞不完全死亡、手术失败和肿瘤再生。最终结果表明，向动脉周围组织注射金纳米颗粒和FeO纳米颗粒可以增强热传递和冰球的进展，使温度分布类似于无血管状态。计算模型的开发可以为医生提供一种适用的工具，帮助他们认识到一种治疗方法对特定病例的有效性，并设计出合适的冷冻手术方案。
