同步辐射相衬成像联合散斑投影技术在肺癌射频消融中的应用研究

Radiofrequency ablation has recently been advocated as an alternative treatment in lung cancer patients who are not surgical candidates, with advantages of fewer traumas, less complications and high repeatability. However, the actual ablation zone and the theoretical zone can not match perfectly. This discrepancy is hard to avoid because of no appropriate imaging techniques which can monitor real-timely the radiofrequency ablation zone accurately at present. Synchrotron radiation phase contrast imaging (PCI) has the characteristics of high-sensitivity and high-resolution, especially for the low-density materials. It can clearly show microbubbles with only a few micrometers in diameter. In the present study, we plan to establish an orthotopic Lewis lung carcinoma model in nude mice and treat with radiofrequency ablation. The microbubbles formation and diffusion process in the ablation zone will be analyzed by PCI. Three-dimensional information of the ablation zone will be deduced using speckle projection technique on the basis of the two-dimensional phase contrast images. Then the radiofrequency ablation zone may be real-timely monitored by using PCI combined with speckle projection technique in the lung cancer model.By comparing with pathologic findings，we will evaluate the reliability and potential research applications of this novel imaging method in radiofrequency ablation for lung cancer.

射频消融是近年来应用于非手术适应证肺癌患者的一种新的治疗方法，具有创伤小、并发症少，可重复性高等优点。但目前所采用的影像学方法难以在术中实时、准确监测射频消融的治疗范围，实际消融范围与理论值往往存在一定的偏差，影响治疗疗效。同步辐射相衬成像具有高敏感、高分辨率的优点，对低密度物质显像良好，能够清晰显示直径仅为数微米的微气泡。本研究拟建立裸鼠Lewis肺癌原位模型，并对其进行射频消融治疗，通过同步辐射相衬成像监测消融区域微气泡形成和弥散过程，联合散斑投影技术在二维的相衬图像上获得肺癌射频消融区域的三维信息，实现对肿瘤消融范围的实时成像监测，结合相应病理学检查结果，研究该新的成像方法在肺癌射频消融术中监测的可靠性及潜在应用价值。

射频消融是近年来应用于非手术适应证肺癌患者的一种新的治疗方法，具有创伤小、并发症少，可重复性高等优点。但目前所采用的影像学方法难以在术中实时、准确监测射频消融的治疗范围，实际消融范围与理论值往往存在一定的偏差，影响治疗疗效。射频消融的范围受到很多因素的影响，如病灶的部位、组织学特性、消融电极的类型，消融时间和热沉效应，这也就导致了肺癌射频消融术后的复发率高于外科手术。为了克服该不足，提高射频消融治疗的精准性和有效性，需要依托实时准确的术中监测手段。同步辐射相衬成像具有高空间和高时间分辨率的优点。相对于传统的吸收成像，该成像方式对低密度物质的密度变化十分敏感，相衬成像是利用同步辐射X线穿透生物组织过程中，其能谱能够保持恒定，但相位发生改变，当X线穿过相位差较大的物质界面时会发生明显偏折，并产生明显的边界增强效应，能够清晰显示直径仅为数微米的微气泡和软组织结构。.本研究第一部分通过建立裸鼠Lewis肺癌原位模型，并对其进行同步辐射吸收和相衬成像，证实相衬成像可更好的显示肺部病灶。通过相衬呈现可发现成瘤仅36小时的肺部肿瘤，同时还可动态观察肺部肿瘤的生长过程。因而同步辐射相衬成像具有肺癌早期筛查和疗效动态评估的潜在应用价值。.研究的第二部分是应用同步辐射相衬成像监测射频消融过程中消融范围的变化。射频消融过程中会产生微气泡，这些微气泡的分布范围与射频消融的范围密切相关。通过相衬成像可观察到常规影像学检查很难显示这些微气泡，当靶区温度达60 ℃，直径数十微米至几毫米的微气泡从消融电极边缘出现并迅速外延，外延的范围与实际消融范围一致。提示相衬成像在射频消融术中实时监测领域具有潜在的应用价值。