Feasibility of Ultra-Low-Dose CT for Bronchoscopy of Peripheral Lung Lesions

Abstract

Background and objectives: Thin-section computed tomography (CT) is essential for identifying small bronchi during bronchoscopy using radial endobronchial ultrasound. Some patients should receive an additional CT for a thin-section image. We performed a retrospective study with a prospectively collected database to identify the optimal radiation dose for thin-section CT during peripheral bronchoscopy. Materials and Methods: In total, 91 patients with peripheral lung lesions underwent thin-section CT (both standard CT as a reference and ultra-low-dose CT (ultra-LDCT)). The patients were randomly assigned to one of four groups according to the ultra-LDCT parameters: group 1 = 120 kVp, 25 mAs; group 2 = 100 kVp, 15 mAs; group 3 = 120 kVp, 5 mAs; and group 4 = 100 kVp, 5 mAs. Two radiologists and two physicians analyzed both the standard CT and ultra-LDCT. Results: The effective doses (EDs) of ultra-LDCT significantly differed among the four groups (median EDs were 0.88, 0.34, 0.19, and 0.12 mSv for groups 1–4, respectively; p < 0.001). Median differences in peripheral airway wall thickness were higher in group 4 than in other groups (differences in median wall thickness measured by two radiologists were 0.4–0.5 mm and 0.8–0.9 mm for groups 1–3 and group 4, respectively). Bronchus signs on ultra-LDCT in groups 1 and 2 were well correlated with those of the standard-dose CT (accuracies of two radiologists and two pulmonary physicians were 95–100%). Conclusions: Our results indicate that ultra-LDCT with ED of >0.34 mSv (ED of group 2) is feasible for peripheral bronchoscopy.

Reduction in Irradiation Dose in Aperture Coded Enhanced Computed Tomography Imager Using Super-Resolution Techniques

“…Our simulation used GNU Parallel [ 10 ], a shell tool for executing parallel jobs. The radiation source in the simulation was divided into several separate ray-tracing simulations where each X-ray source runs individually; this process shortens the simulation running time.…”

“…In this paper, we would like to expend the use of multi pinholes techniques to more medical modalities such as Computerized Tomography (CT). In the CT procedure, there is a need for a novel configuration and operation technique to enable three-dimensional imaging of a body with decreased radiation level and preferably increasing resolution compared to current conventional CT techniques [ 9 , 10 , 11 ].…”