NDE (Nondestructive Evaluation) of wood was performed using X-ray CT technique in order to determine the applicability of this technology to ancient wooden buildings in the field. Two main objectives were studied to consider applicability as well as accuracy. First, the most suitable number of radiographs for reconstructing proper X-ray CT images was determined. Secondly, X-ray CT images using SIRT were reconstructed using various numbers of radiographs in order to consider the possible effects of absent projection data in field applications. As a result of this study, 9 radiographs were determined to be the most suitable number for this application. Brown-rotted part in wood was also detected by X-ray CT images using 9 radiographs. It was concluded that even there exists some absent projection data, CT images can be reconstructed with high accuracy.