1.	An endotracheal intubation tube was placed into the trachea, and whole lungs were fixed by instillation of 10% neutral buffered formalin (NBF) solution into the airway with pressure of 0.04 MPa for 30 minutes.
2.	Following fixation, the treated lung was examined to identify needle insertion tracts, and ablation zones were sectioned parallel to the tract when identified.
3.	The entire lung was step-sectioned at 3–5 mm intervals when the needle path could not be observed.
4.	The representative ablation sections were fixed in 10% NBF solution, processed routinely in ethanol and xylene, embedded in paraffin, sectioned at 4-μm thickness, and stained with hematoxylin and eosin.
5.	The largest cross section of each ablation with surrounding untreated lung parenchyma was captured in large histology slides.