Fusion of SLAM and Freehand Portable X-ray Devices For Mobile Computed Tomography

While conventional computed tomography (CT) remains an irreplaceable tool for modern medical diagnostics, it relies on massive setups, making it unsuitable for emergency and ambulance application scenarios where rapid on-site visualization is necessary. In the present work, we address this limitation by proposing a new freehand CT technology based on the algorithmic enhancement of existing radiographic hardware to achieve X-ray 3D imaging in extremely low-dose conditions for freehand trajectory-based tomography. Our setup relies on three main steps: (1) data acquisition with a manually positioned portable X-ray source and flat-panel detector; (2) anchor-based and simultaneous localization and mapping (SLAM) inspired automatic scene geometry calibration; and (3) few-view, low-angle, and low-dose tomographic iterative reconstruction with L0-regularization. We discuss the fundamental problems and technical difficulties arising in both trajectory localization and 3D image reconstruction, and we present solutions for each component of the technology. The developed technology enables a portable, suitcase-scale realization of a CT system with diagnostic quality resulting from only 5–15 X-ray projections with an extreme low-dose load on patients. The achieved performance opens up potential for applications in a number of different fields including, but not limited to, emergency and disaster medicine, industrial field inspections, forensics, cultural heritage studies, and scientific applications where conventional CT systems are unavailable or impractical.