Experimental studies and computer simulations were performed to evaluate the potential of X-ray imaging to quantify the hydraulic characteristics of a vapor-liquid contactor. Cross-sectional images of a 6-in-diameter air-water contactor containing Mellapak 500Y structured packing were obtained at various elevations, air flow rates, and liquid flow rates. In addition, stationary transmission measurements were obtained to provide an indication of the variability of flow in the contactor over the duration required to acquire an image. Computer simulations of the imaging technique were performed to validate the cause of ring-like artifacts observed in the images obtained from the experiments. It was concluded that the subpositions required for the pseudo-third-generation scan geometry are a primary cause of the artifacts. (C) 2004 Elsevier Ltd. All rights reserved.