背景:肺癌是全球癌症死亡的主要原因,诊断仍然具有挑战性。肺癌从小结节开始,早期准确诊断,可以及时手术切除恶性结节,同时避免良性结节患者不必要的手术。
目的:Cole弛豫频率(CRF)是衍生的电生物阻抗特征,其可用于区分癌组织与正常组织。
方法:用NoduleScan在30例接受非小细胞肺癌切除术的志愿者患者新鲜切除的肺组织中进行离体人体测试。将肿瘤的CRF和相对于肿瘤的远处正常肺组织与组织病理学标本进行比较,以建立潜在的即时诊断算法。用于体内动物试验,用皮下注射到每只小鼠右侧腹中的异种移植人肺癌肿瘤细胞植入20只小鼠。对活体动物上的肿瘤和安乐死后的肿瘤进行光谱阻抗测量。将这些CRF测量值与健康小鼠肺组织进行比较。对于离体猪肺测试,猪肺与气管一起接受。拆除声箱后,连接呼吸机以对肺加压并模拟呼吸.在裂片的不同位置,肺的表面被切割,以产生一个口袋,可以容纳从体内动物试验获得的肿瘤。肿瘤被放置在肺的表面下,并且将电极放置在肿瘤正上方的肺表面上,但在肿瘤和电极之间有肺组织。频谱阻抗测量是在肺部处于放气状态时进行的,充气状态,以及在通货膨胀-通货紧缩过程中模拟呼吸。
结果:在30例患者中评估的60个样本中,NoduleScan允许在肿瘤和远处正常组织中CRF清晰分离的患者中以高度的敏感性(97%)和特异性(87%)进行现成的区分。在25个异种移植小动物模型标本中测得,CRF与人体内测量中观察到的分离对齐。CRF成功测量了植入离体猪肺的肿瘤,和CRF测量值与以前的加压和非加压肺测试一致。
结论:如先前在乳腺组织中所示,在1kHz-10MHz范围内的CRF能够区分非小细胞肺癌和正常组织。Further,体内小动物研究证明了这一点,灌注肿瘤具有与乳腺组织和人离体测试中所示相同的CRF特征。肺的膨胀和收缩对CRF特征没有影响。随着额外的发展,从频谱阻抗测量得出的CRF可以允许指导手术切除的现场护理诊断。
BACKGROUND: Lung cancer is the world\'s leading cause of cancer deaths, and diagnosis remains challenging. Lung cancer starts as small nodules; early and accurate diagnosis allows timely surgical resection of malignant nodules while avoiding unnecessary surgery in patients with benign nodules.
OBJECTIVE: The Cole relaxation frequency (CRF) is a derived electrical bioimpedance signature, which may be utilized to distinguish cancerous tissues from normal tissues.
METHODS: Human testing ex vivo was conducted with NoduleScan in freshly resected lung tissue from 30 volunteer patients undergoing resection for nonsmall cell lung cancer. The CRF of the tumor and the distant normal lung tissue relative to the tumor were compared to histopathology specimens to establish a potential algorithm for point-of-care diagnosis. For animal testing in vivo, 20 mice were implanted with xenograft human lung cancer tumor cells injected subcutaneously into the right flank of each mouse. Spectral impedance measurements were taken on the tumors on live animals transcutaneously and on the tumors after euthanasia. These CRF measurements were compared to healthy mouse lung tissue. For porcine lung testing ex vivo, porcine lungs were received with the trachea. After removal of the vocal box, a ventilator was attached to pressurize the lung and simulate breathing. At different locations of the lobes, the lung\'s surface was cut to produce a pocket that could accommodate tumors obtained from in vivo animal testing. The tumors were placed in the subsurface of the lung, and the electrode was placed on top of the lung surface directly over the tumor but with lung tissue between the tumor and the electrode. Spectral impedance measurements were taken when the lungs were in the deflated state, inflated state, and also during the inflation-deflation process to simulate breathing.
RESULTS: Among 60 specimens evaluated in 30 patients, NoduleScan allowed ready discrimination in patients with clear separation of CRF in tumor and distant normal tissue with a high degree of sensitivity (97%) and specificity (87%). In the 25 xenograft small animal model specimens measured, the CRF aligns with the separation observed in the human in vivo measurements. The CRF was successfully measured of tumors implanted into ex vivo porcine lungs, and CRF measurements aligned with previous tests for pressurized and unpressurized lungs.
CONCLUSIONS: As previously shown in breast tissue, CRF in the range of 1kHz-10MHz was able to distinguish nonsmall cell lung cancer versus normal tissue. Further, as evidenced by in vivo small animal studies, perfused tumors have the same CRF signature as shown in breast tissue and human ex vivo testing. Inflation and deflation of the lung have no effect on the CRF signature. With additional development, CRF derived from spectral impedance measurements may permit point-of-care diagnosis guiding surgical resection.