There is a need for a reliable, safe, and bedside lung imaging tool that can be used in intensive care units (ICUs). Traditional medical imaging devices such as CT and MRI cannot be easily used. These imaging methods are costly, are not readily usable at the bedside, and may involve ionizing radiation, which carries potential risks, particularly with repeated use. Due to its many advantages, ultrasound imaging is used extensively in various lung applications and in ICUs. As a result, this work presents the first successful demonstration of an innovative ultrasound imaging tool termed “ultrasound computed tomography” (USCT), a transmission imaging tool for monitoring the human chest. The change of acoustic velocity and attenuation of the acoustic field in the human thorax provide functional information on the respiratory system. This article is the first to demonstrate vivo imaging of the human thorax using USCT, which can potentially be used for lung pathologies through cross section and volumetric chest imaging. Detailed experimental data is presented from eight healthy volunteers using a wearable sensor array to monitor the various breathing phases using the new USCT system. The results of the new imaging approach outlined here pave the way for future clinical studies and the use of USCT in ICUs at a patient bedside in a safe, low cost, and reliable way. Finally, a data-driven approach was trained using ray-based simulated data and tested on in vivo data for absolute lung and heart imaging. The data-driven approach is first tested on lab phantom experiments providing verifiable working, providing confidence in human data results.