Chang Hwailuh, Liao Kuo Sheng, Hsieh Yei-San
Taoyuan General Hospital, Ministry of Health and Welfare, Taoyuan.
J Thorac Dis. 2020 Jul;12(7):3611-3621. doi: 10.21037/jtd-19-3887.
Trans-bronchoscope treatment for early stage small peripheral lung cancer, such as photodynamic therapy (PDT), has been investigated. However, despite the efficacy of PDT, light delivery issues limit its application. A method of administering mineral oil with a high refractive index (RI) was previously proposed to enhance light delivery in branched or bent anatomic structures. Lipiodol has a high RI and an exhaustive history of use as a contrast medium for bronchography. We aimed to determine whether the use of lipiodol, like mineral oil, could enhance the illumination effect and therapeutic range of PDT for peripheral lung tumors.
We injected lipiodol into a pig lung model, guided by a bronchoscope under fluorescent surveillance, to simulate future treatment in humans, and then illuminated with PDT laser fiber to the lipiodol-infused lung to test the technique feasibility in a pig orally administered 20 mg/kg of 5-aminolevulinicc acid (5-ALA) 2 hours before treatment. We also attempted to determine the maximal tolerable light dose in this pilot study for the future studies in human.
We successfully injected lipiodol into peripheral lungs by this technique. The pig could tolerate up to a total of 40 mL of lipiodol and 800 J of red light, without severe acute fetal injury in a non-cancerous lung.
The technique of injecting lipiodol using bronchoscopy under fluorescent guidance was feasible in a pig model. We can apply the guide sheath through bronchoscopy under fluoroscope inspection. Lipiodol can be used as a light diffuser for the peripheral lung tumor PDT model. No severe lethal acute lung injury was caused by this PDT model under careful manipulation. Additional studies evaluating the dose correlation of the photosensitizer and light are needed.
已经对早期小周围型肺癌的经支气管镜治疗进行了研究，如光动力疗法（PDT）。然而，尽管PDT有效，但光传输问题限制了其应用。此前有人提出一种给予高折射率（RI）矿物油的方法，以增强在分支或弯曲解剖结构中的光传输。碘油具有高RI，并且作为支气管造影的造影剂有着广泛的使用历史。我们旨在确定碘油是否像矿物油一样，能够增强PDT对周围型肺肿瘤的照明效果和治疗范围。
在荧光监测下，通过支气管镜将碘油注入猪肺模型，以模拟未来在人体中的治疗，然后用PDT激光光纤照射注入碘油的肺，以测试该技术在治疗前2小时口服给予20mg/kg 5-氨基乙酰丙酸（5-ALA）的猪中的可行性。我们还试图在这项初步研究中确定未来人体研究的最大耐受光剂量。
通过该技术，我们成功地将碘油注入周围肺组织。在非癌性肺中，猪能够耐受总计40mL碘油和800J红光，而无严重急性肺损伤。
在荧光引导下通过支气管镜注射碘油的技术在猪模型中是可行的。我们可以在荧光镜检查下通过支气管镜应用引导鞘。碘油可作为周围型肺肿瘤PDT模型的光扩散剂。在仔细操作下，该PDT模型未引起严重致命性急性肺损伤。需要进一步研究评估光敏剂与光的剂量相关性。
