B-mode ultrasound (echography) has long been a first-line examination for the diagnosis of many diseases in children. The other modalities, such as X-ray or magnetic resonance imaging, are often associated with inconveniences of variable importance (cost, irradiation, sedation, accessibility) that are constraining for pediatric applications . But B-mode ultrasound has difficulty penetrating bone and the locks associated with the in-vivo configuration are still numerous: image resolution and the contrast in the deep zone; accessibility of anatomical sites, or in between the two leg and arm bones. Ultrasonic Computed Tomography (USCT) is a relevant modality to bone tissues imaging , . The acquisition geometry of the signals is no longer linear nor sectoral, as in B-mode ultrasound, but circular in the orthogonal plane, and based on a multiplexed dual-frequency 2D-ring antenna allowing electronical and mechanical scanning. The antenna supports 8 fixed transducers distributed over 360�. The Mistras-Eurosonic? multiplexer is equipped with an 8-by-8 parallel-channel acquisition system. The 8 transducers are Imasonic? piezo-composite transducers with a center frequency of 1MHz and 2.25MHz. Each transducer is 60 mm high and 56 mm in diameter. These transducers have cylindrical focusing with a focal length of 150 mm, a lateral aperture size of 40 mm and an axial aperture size of 30 mm. The slice thickness is 3 mm. Results obtained on rectified non-circular cylindrical tubes, on paired bones (Sawbones�) are presented. References  P. Petit et al., ?Am. J. Roentgenol., vol. 176, no. 4, pp. 987?990, Apr. 2001.  P. Lasaygues et al., Proceedings of the Int. Workshop on MUST, Speyer, Germany, 2017.  S. Bernard, et al., Phys. Med. Biol., vol. 62, no. 17, pp. 7011?7035, Aug. 2017. Acknowledgements This research was supported by the Provence-Alpes-Côte d'Azur ? PACA Regional Council, under Grant No.2016₀2696.