Multisource X-Ray and CT: Lessons Learned and Future Outlook

Neculaes, V.B.; Edic, Peter M.; Frontera, Mark; Caiafa, Antonio; Wang, Ge; Man, Bruno De

doi:10.1109/access.2014.2363949

Cited by 31 publications

(31 citation statements)

References 62 publications

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“…Note that this definition of S includes the possibility of multiple simultaneous x-ray sources [4], each of which would have its own focal spot. Thus, while we speak here of a single focal spot, the mathematics allows multiple focal spots.…”

Section: Modeling An X-ray Source With Its Focal Spot Width Divided Imentioning

confidence: 99%

“…This was an example of a trade-off between patient safety and image quality. Now we are faced with the further trade-off between image quality (usually presumed to be a measure of diagnostic accuracy) and the computer time needed to achieve higher image quality [2,186,201] (Figure 12), especially because faster scanners [4,274,278] mean less time to do the computing. Certainly Moore's Law applies here [279,280], as well as in other domains [281][282][283], as we have not yet reached limits to computer speed.…”

Section: A3mentioning

confidence: 99%

“…Despite the passage of 56 years, clinical CT scanners still use detectors that are about 1 mm in the smallest dimension [4]. They generally do not take advantage of advances in reduced detector pixel width from the fields of digital radiography, microtomography and nanotomography ( Figure 1, Table 1).…”

Section: Introductionmentioning

confidence: 99%

“…Traditionally, CT algorithms treat the focal spot x-ray source as if it were a single mathematical point [152], despite the fact that the finite focal spot width is known to limit the resolution of CT [4,153,154]. Our FoxelCT algorithm accounts for the focal spot as an extended source.…”

Section: Introductionmentioning

confidence: 99%

“…In an ideal system, the origin of the x-ray flux is treated as a point source to maximize spatial resolution. In reality, this region must have a finite area to decrease the maximum heat flux on the target/anode for x-ray generation" [4].…”

Section: Introductionmentioning

confidence: 99%

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Foxels for high flux, high resolution computed tomography (foxelct) Using broad x-ray focal spots

Alvare¹,

Gordon²

2017

Radiol Diagn Imaging

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Purpose: In general, there is a reciprocal relationship between the width and flux from an x-ray focal spot (corresponding to spatial resolution and photon noise), so that large focal spots are eschewed in computed tomography (CT) and projection and CT mammography. We wish to overcome this limitation. The goal of foxel based computed tomography (FoxelCT) is to achieve spatial resolution limited by the detector pixel size rather than the focal spot size, and therefore permit the use of much smaller detector pixels and/or larger focal spots in clinical CT. Methods:Rather than using the standard approach of treating the x-ray source as a point, we digitally represent the focal spot as an emission picture consisting of pixels we call foxels (FOcal spot piXELS). Intersections of foxel rays with reconstruction voxels are approximated using the Wu antialiasing line drawing algorithm. All foxel rays in the x-ray light field impinging on a given detector pixel are, in effect, lumped together into a single "passage" or compound ray sum. In this introductory paper noise and other effects that degrade CT are not considered allowing us to demonstrate the upper bound of improvement afforded by the geometry of foxels. The FoxelCT algorithm is a generalization of MART (Multiplicative ART). Results:We show, by simulating a fan beam body scanner configuration, that the loss in resolution versus focal spot size is much slower using foxels compared to the loss when representing the focal spot as a point source. For any given focal spot size, approximating it as a point is always worse than using foxels and furthermore introduces anatomical distortions.Conclusions: Foxels permit the use of larger focal spots and thus greater x-ray photon flux with little loss of resolution. Future scanners could take advantage of foxels to increase the ratio of focal spot size to detector pixel size, via bigger focal spots and/or smaller detector pixels. Existing scanners could be immediately enhanced in image quality via incorporation of foxels in their software. Foxels are applicable to any form of radiological imaging that uses focal spots of finite width, including multisource scanners.

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Section: Modeling An X-ray Source With Its Focal Spot Width Divided Imentioning

confidence: 99%

Section: A3mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Foxels for high flux, high resolution computed tomography (foxelct) Using broad x-ray focal spots

Alvare¹,

Gordon²

2017

Radiol Diagn Imaging

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Optimization of a secondary VOI protocol for lung imaging in a clinical CT scanner

Larsen

Gopalakrishnan

Yao

et al. 2018

J Applied Clin Med Phys

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We present a solution to meet an unmet clinical need of an in‐situ “close look” at a pulmonary nodule or at the margins of a pulmonary cyst revealed by a primary (screening) chest CT while the patient is still in the scanner. We first evaluated options available on current whole‐body CT scanners for high resolution screening scans, including ROI reconstruction of the primary scan data and HRCT, but found them to have insufficient SNR in lung tissue or discontinuous slice coverage. Within the capabilities of current clinical CT systems, we opted for the solution of a secondary, volume‐of‐interest (VOI) protocol where the radiation dose is focused into a short‐beam axial scan at the z position of interest, combined with a small‐FOV reconstruction at the xy position of interest. The objective of this work was to design a VOI protocol that is optimized for targeted lung imaging in a clinical whole‐body CT system. Using a chest phantom containing a lung‐mimicking foam insert with a simulated cyst, we identified the appropriate scan mode and optimized both the scan and recon parameters. The VOI protocol yielded 3.2 times the texture amplitude‐to‐noise ratio in the lung‐mimicking foam when compared to the standard chest CT, and 8.4 times the texture difference between the lung mimicking and reference foams. It improved details of the wall of the simulated cyst and better resolution in a line‐pair insert. The Effective Dose of the secondary VOI protocol was 42% on average and up to 100% in the worst‐case scenario of VOI positioning relative to the standard chest CT. The optimized protocol will be used to obtain detailed CT textures of pulmonary lesions, which are biomarkers for the type and stage of lung diseases.

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A unified material decomposition framework for quantitative dual‐ and triple‐energy CT imaging

et al. 2018

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A unified framework for both DECT and TECT imaging has been established for the accurate extraction of material compositions using currently available commercial DECT configurations. The novel technique is promising to provide an urgently needed solution for several CT-based diagnostic and therapy applications, especially for the diagnosis of cardiovascular and abdominal diseases where multicontrast imaging is involved.

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Multisource X-Ray and CT: Lessons Learned and Future Outlook

Cited by 31 publications

References 62 publications

Foxels for high flux, high resolution computed tomography (foxelct) Using broad x-ray focal spots

Foxels for high flux, high resolution computed tomography (foxelct) Using broad x-ray focal spots

Optimization of a secondary VOI protocol for lung imaging in a clinical CT scanner

A unified material decomposition framework for quantitative dual‐ and triple‐energy CT imaging

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