Volumetric computed tomography with carbon nanotube X-ray source array for improved image quality and accuracy

Abstract

Cone beam computed tomography (CBCT) is widely used in medical and dental imaging. Compared to a multidetector CT, it provides volumetric images with high isotropic resolution at a reduced radiation dose, cost and footprint without the need for patient translation. The current CBCT has several intrinsic limitations including reduced soft tissue contrast, inaccurate quantification of X-ray attenuation, image distortions and artefacts, which have limited its clinical applications primarily to imaging hard tissues and made quantitative analysis challenging. Here we report a multisource CBCT (ms-CBCT) which overcomes the shortcomings of the conventional CBCT by using multiple narrowly collimated and rapidly scanning X-ray beams from a carbon nanotube field emission source array. Phantom imaging studies show that, the ms-CBCT increases the accuracy of the Hounsfield unit values by 60%, eliminates the cone beam artefacts, extends the axial coverage, and improves the soft tissue contrast-to-noise ratio by 30–50%, compared to the CBCT configuration.

A carbon nanotube x-ray source array designed for a new multisource cone beam computed tomography scanner

“…The CNT x-ray source array and the multisource collimator described here have been integrated into a prototype ms-CBCT. The performance of the scanner has been characterized and compared to the current clinical dental CBCT in recent publication (Xu et al 2023b). Phantom imaging studies have showed 60% increase in the HU accuracy, 75% improvement in the HU uniformity, 30%-50% enhancement in the soft tissue contrast-to-noise ratio, and elimination of the cone beam artefacts, compared to the current clinical dental CBCT at similar imaging doses.…”

“…We recently designed a medium field of view ms-CBCT scanner for maxillofacial imaging using a CNT x-ray source array. Phantom imaging studies have demonstrated the ms-CBCT increases the soft tissue CNR, reduces the HU error and nonuniformity, and essentially eliminates the cone-beam artifacts, compared to a conventional CBCT operating under otherwise similar conditions (Xu et al 2023b). Here we report the design and detailed evaluation of the CNT x-ray source array.…”

“…Many hardware and software-based methods have been proposed with varying degrees of success, including 2D anti-scattering grid, scatter estimation through measurement and simulation, noncircular imaging orbit, synthetic CT and machine learning (Zhu et al 2009, Ruhrnschopf And and Klingenbeck 2011, Rührnschopf and Klingenbeck 2011, Tang et al 2018, Thummerer et al 2020, Fahrig et al 2021, Rusanov et al 2021, Hatamikia et al 2022. Recent studies have demonstrated that the performance of a CBCT can be improved significantly by replacing the single wide cone angle x-ray tube with multiple x-ray beams along the axial direction (Yin et al 2009, Becker et al 2020, Xu et al 2023a, 2023b. This multisource CBCT (ms-CBCT) design eliminates the root cause problem of the current CBCT, the large x-ray beam cone angle, by collimating the radiation from each source to only a narrow section of the object and using the multiple collimated beams to collectively cover the same field-of-view (FOV) as a conventional CBCT.…”

Improving the accuracy of bone mineral density using a multisource CBCT

“…Recently, advances in machine learning 20,21 and dual-energy CBCT [22][23][24] have shown promise in improving accuracy. Our recent work introduces a multisource CBCT (ms-CBCT) technology [25][26][27] , which addresses the key limitations of conventional CBCT by employing a stack of narrowly collimated X-ray beams instead of a single X-ray tube. This novel approach significantly reduces scatterprimary ratio and cone beam artifacts and enhances the uniformity and accuracy of CT HU values 25,27 .…”

“…Our recent work introduces a multisource CBCT (ms-CBCT) technology [25][26][27] , which addresses the key limitations of conventional CBCT by employing a stack of narrowly collimated X-ray beams instead of a single X-ray tube. This novel approach significantly reduces scatterprimary ratio and cone beam artifacts and enhances the uniformity and accuracy of CT HU values 25,27 . In this study, we assess the accuracy of ms-CBCT in measuring bone density in mandibular and maxilla regions, comparing it with conventional CBCT.…”