There has bveen a tramendous change during the past few years in the manner of treatment of tubrerculosis. Still the presence of a cavity in pulmonary tuberculosis isof extreme importance for the treatment andfurther prognosis of the disease. Any method of examination which helps to diagnose cavities more accurately is of considerable value. Body section radiography or tomography, originally discovered by Bocage in 1921, is such a method, but it should by no means be considered the "last word" in the detection of cavities. Still there remains certain problems that must be solved by further studies. Our study is to check the accuracy of the tomographic interpretations by correlating them with the actual lung findings in 63 cases which received either pneumonectomy or lobectomy at the Dept. of Thoracic Surgery, Severance Hospital, Yonsei University, Seoul, Korea.ul, Korea.