Finite element analysis of constant-power invasive microwave coagulation of liver tumors

Invasive microwave coagulation (IMC) therapy is a newly developed method for the treatment of liver tumors. In this paper, the constant-power IMC therapy is discussed. Three-dimensional finite element analysis for "alternative" heating pattern and a large blood vessel bioheat model are performed. The objective is to study: (i) the effects of "alternative" heating pattern of invasive microwave antennas on reducing the peak temperature which can be up to 140℃. Therefore, "alternative" heating pattern can improve the security of IMC; (ii) modeling impact of large vessels on heat transfer of surrounding tissue and the formation of the coagulation lesion. Corresponding in vivo pig experiments are provided to compare with the simulation results. The results indicate that: (i) the "alternative" heating pattern was efficient in reducing the peak temperature and diminishing the dimension of "super hot" area; (ii) the heat loss due to the cooling of the large blood vessel is so great that attempting to compensate     

微波消融治疗肝癌中的若干热学问题

针对微波消融治疗肝癌中遇到的一些热学问题进行了分析和讨论,对肝组织对微波的比吸收率的确定方法、温度场的数值模拟、单一微波源形成的凝固区大小和形状、分时控制的多源凝固区组合方法等进行了研究.结果表明,模拟结果与实测凝固区有良好的一致性,采用分时控制的多源凝固区组合技术能实现肿瘤的适形治疗.     

CT引导建立兔肺VX2肿瘤模型的实验研究

目的 建立适合微波消融的兔肺肿瘤模型.方法 新西兰大白兔36只,CT引导下穿刺,将载有VX2肿瘤组织悬液的亲水凝胶接种于右肺内.结果 接种后14～26 d,CT检查证实34只新西兰大白兔肺内有肿瘤生长,其中26只呈单发结节,直径0.5～0.8 cm,兔肺VX2肿瘤模型成功率为72.2%(26/36);另有2只肺内呈多发结节生长,并出现胸腔积液;4只累及纵隔;2只出现胸壁种植转移.接种过程未出现气胸、出血等并发症.结论 本实验建模方法安全、有效,并可在肺内局部形成较大体积的实体瘤,能满足微波消融治疗肺癌的研究需要,因此所建兔肺VX2肿瘤模型是成功的.     

肝脏肿瘤声衰减(FDA)的活体测量

本文报道肝脏肿瘤的声衰减(FDA)的活体测量的研究,着重探讨肝脏良性及恶性肿瘤组织对声衰减(FDA)的影响。 仪器 使用ALOKA-270-TC超声诊断仪,内有用过零点法测量声衰减系数软件,不但可以实时显示组织的二维图像,并且可以对靶区取样测量FDA值。探头频率为3.5MHz。 资料1.对照组即正常肝脏40例,男20例,女20例,年龄23～72岁。2.肝脏疾病组59例,其中肝细胞肝癌40例,肝血管癌6例,肝细胞腺瘤3例,局限性脂肪肝7例,肝增生性病变3例。本组病例全部有手术或穿剌活检的组织病理诊断。 结果 声衰减(FDA)的测值结果如下: 正常肝脏为0.5300.03dB/…