Make it count with photon-counting computed tomography: a revolution in technology for investigating the airways

Computed tomography (CT) imaging is the mainstay for high-resolution clinical and research evaluation of the lungs for nodule detection, monitoring and measurement of emphysema and airways disease, and diagnosis and monitoring of interstitial lung abnormalities [1]. High-resolution CT also enables virtual bronchoscopy to non-invasively visualise the lumen of the tracheobronchial tree [2], similar to the path taken by a fibreoptic bronchoscope. While CT technology has substantially advanced over the past five decades, to enable rapid acquisition of such high-resolution images, repeated exposure to ionising radiation remains a significant concern, especially in young persons and females of child-bearing age [3, 4]. Moreover, the lower limit of CT spatial resolution has been largely fixed by detector technology and available computing power. For thoracic CTs, these shortcomings have meant significant radiation exposure over a relatively large field-of-view (for patients) to achieve a (modest) spatial resolution of ∼0.5–1.0 mm.