Shown in this paper are recent accomplishments of robust leading edge technologies in the guided wave technique and the technology transfer to the Gas and Petrochemical Industries. Focusing of guided wave beams is a key for success, compared to conventional axisymmetric excitation. Guided wave scanning and significant sensitivity enhancement are established via the newly implemented focusing scheme. In addition, using both longitudinal and torsional modes is essential to improve sensitivity and reliability in data analysis over the conventional technique based on only longitudinal or torsional. The related theoretical studies and experimental data are also presented along with field test results for confirmation. (C) 2009 Elsevier Ltd. All rights reserved.