[A pilot study with lung-cancer screening CT (LSCT) at the secondary screening for lung cancer detection]

We have developed computed tomography (CT) equipment for lung-cancer screening (named LSCT) that can be used exclusively for lung-cancer screening with spiral volumetric CT and is available on a screening car. A pilot study with LSCT was performed from November 1992 to January 1993 on 118 screenees at the secondary examination of lung-cancer screening. Scan parameters were as follows: 120 kVp, 50 mA, slice thickness 10 mm, table feed 10 mm/sec, scan time 2 sec/rotation. All the screenees were scanned under quiet respiration instead of the breath-hold technique. Under these scan parameters, LSCT images were almost free from respiratory motion artifacts even at the lung base. Continuity of the bronchial tree and vessels was well maintained in consecutive slices. Pulmonary nodules approximately 5 mm in diameter were clearly depicted. By LSCT, 43 of 118 screenees were diagnosed to need further examinations. And 33 out of 43 screenees underwent detailed examinations. Finally, 16 lung cancers were confirmed. Ten of 16 patients with lung cancer underwent surgery; nine were in stage I and one in stage IIIA. LSCT was considered to be useful in lung-cancer screening.