Fielding D I, Buonaccorsi G, Hanby A, Hetzel M R, Bown S G
Department of Surgery, University College London Medical School, UK.
Thorax. 1998 Aug;53(8):692-7. doi: 10.1136/thx.53.8.692.
Management of peripheral lung tumours may be risky in patients with poor lung function or in the elderly. A new possibility is interstitial laser photocoagulation (ILP) in which tumours are gently coagulated using thin laser fibres placed percutaneously under radiological guidance. This could have a useful palliative role in selected patients, but to be safe the effects on normal lung parenchyma must first be understood. This paper describes the creation and healing of ILP lesions in the normal rat lung.
ILP was performed using single laser fibres placed percutaneously in the left lung of normal rats under general anaesthetic with radiological guidance (laser power 1-3 W at 805 nm, treatment time 250-1000 s). The lesion size and healing were studied in rats killed at times from three days to six months after treatment, the bursting pressure was measured, and any complications noted.
Zones of necrosis up to 12 mm in diameter were produced, the size depending on the laser power and treatment time. Histological examination showed typical thermal effects with complete healing with fibrosis by two months. The effect was very localised with remarkably little effect on the structure and function of the rest of the lung. Adverse effects in the lung parenchyma only occurred if the ILP lesion involved the hilar vessels or the oesophagus, causing pulmonary congestion and perforation, respectively. Pneumothorax was seen in 6% of cases.
ILP with a single fibre can produce a localised zone of necrosis in normal lung parenchyma which heals safely and which has little effect on the rest of the lung. Further study of this technique using multiple fibres in a larger animal model is warranted to see if it is feasible and safe to produce a large enough volume of necrosis to be of value in the treatment of small peripheral lung tumours in patients who are unsuitable for surgery or palliative radiotherapy.
对于肺功能差的患者或老年患者，周围型肺肿瘤的治疗可能具有风险。一种新的治疗方法是间质激光光凝术（ILP），即在放射学引导下经皮插入细激光纤维，对肿瘤进行温和的凝固。这在特定患者中可能具有有用的姑息治疗作用，但要确保安全，必须首先了解其对正常肺实质的影响。本文描述了正常大鼠肺中ILP损伤的形成和愈合过程。
在全身麻醉下，于放射学引导下经皮将单根激光纤维插入正常大鼠的左肺进行ILP（激光波长805nm，功率1 - 3W，治疗时间250 - 1000秒）。在治疗后3天至6个月的不同时间点处死大鼠，研究损伤大小和愈合情况，测量爆破压力，并记录任何并发症。
产生了直径达12mm的坏死区域，其大小取决于激光功率和治疗时间。组织学检查显示典型的热效应，两个月时完全愈合并伴有纤维化。该效应非常局限，对肺其余部分的结构和功能影响极小。仅当ILP损伤累及肺门血管或食管时，才会在肺实质中出现不良反应，分别导致肺充血和穿孔。6%的病例出现气胸。
单根纤维的ILP可在正常肺实质中产生局部坏死区域，该区域可安全愈合，对肺的其余部分影响很小。有必要在更大的动物模型中使用多根纤维对该技术进行进一步研究，以确定产生足够大体积的坏死区域在治疗不适合手术或姑息性放疗的小周围型肺肿瘤患者中是否可行且安全。
