Design and Evaluation of Innovative Mobile X-Ray Technology for Rapid and Accurate Diagnosis of Thoracic Disease in Critically Ill Patients

Dual-energy (DE) imaging consists of acquiring paired "low" and "high"-energy x-ray images. The use of DE to improve radiological contrast was first described by Jacobson et al in 1958; followed by Mistretta et al and Alvarez and Macovski in the mid-1970s. With the advent of new digital X-ray detectors that provide high dose efficiency and rapid readout of digital X-ray projections, there has been renewed interest in using DE x-ray imaging for lung nodule detection. More recently, portable x-ray detectors have made bedside DE imaging possible. Jabri et. al. presented a portable DE system with novel respiratory and cardiac gating, and Hoggarth et. al. investigated the potential for DE subtraction in improving the visualization of lung tumors while performing image-guided radiotherapy.

The investigators group is experienced in investigating DE for lung nodule detection, this theoretical framework was instrumental in optimizing a clinical prototype for high-performance DE chest X-ray. It identified optimal DE image acquisition and decomposition techniques, and validated the approach in comparison to human observer performance. The analysis further demonstrated that - given a high-performance flat plate detector, optimal acquisition and decomposition - DE chest X-ray is possible at the same dose as conventional computer radiography (CR) and digital radiography (DR) chest X-ray, while significantly improving conspicuity of subtle lung nodules by the reduction of overlying background noise. The DE work undertaken by our group is unique in terms of providing a clear theoretical framework for optimizing a clinical prototype for best performance in terms of image quality and patient exposure to ionizing radiation.