Identification of small lung nodules: technique of radiotracer-guided thoracoscopic biopsy

This study describes a thoracoscopic technique to reliably locate and excise lung nodules that were not thought to be thoracoscopically visible or instrumentally palpable.

Initial laboratory studies succeeded in selecting a technetium 99m gamma-emitting solution, technetium 99m macro-aggregated albumin, that remained localized in lung parenchyma after percutaneous placement. Subsequently, 84 patients with solitary small nodules underwent computed tomography (CT)-guided percutaneous placement of this technetium solution in or near the nodule. Thoracoscopic localization with a radioprobe and excisional biopsy followed.

In 3 patients, the previous lesion was not present on the CT scan done on the day of surgery. The 81 remaining patients underwent radiotracer placement and operation. No tracer activity was present in the lung in 4 patients, and open thoracotomy was necessary to locate the lesion. The lesion was successfully localized and excised in 77 patients (95.1%), and 71 underwent thoracoscopic excisional biopsy. Four underwent intentional thoracotomy for deep small nodules in which the tracer was used to guide the open biopsy. Two required conversion from thoracoscopy to thoracotomy because the anatomic location of the lesion prevented a thoracoscopic staple excision. Fifty percent of the lesions were benign, 39% were primary lung cancers, and additional 11% were either solitary metastatic lesions or lymphoma. No patients died, and morbidity rate was 16% (arrhythmias or pneumothoraces).

Radiotracer-guided thoracoscopic biopsy was 95% reliable for subsequent surgical successful localization and excision of small nodules. This technique can be expanded to localize deep lesions for open thoracotomy and be used to prevent thoracotomy in 50% of patients with benign disease.