Timing resolution in double-sided silicon photon-counting computed tomography detectors

Sundberg, Christel; Persson, Mats; Wikner, J. Jacob; Danielsson, Mats

doi:10.1117/1.jmi.10.2.023502

Cited by 2 publications

(1 citation statement)

References 32 publications

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“…Current semiconductor detectors used for photon counting imaging can only reach 1 ns resolution for TOF x-ray measurements (Sundberg et al 2023), making scintillators the only option. Counting individual photons using scintillators is a challenge because the large decay time of common materials makes separating events difficult, but it was recently shown that sufficient count rate was achievable using LuAP: Ce and LaBr 3 (van der Sar et al 2021).…”

Section: Discussionmentioning

confidence: 99%

Time-of-flight scatter rejection in x-ray radiography

Rossignol,

Bélanger,

Gaudreault

et al. 2024

Phys. Med. Biol.

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Objective Time-of-flight (TOF) scatter rejection allows for identifying and discarding scattered photons without the use of an anti-scatter grid (ASG). Although TOF scatter rejection was initially presented for cone-beam CT, we propose, herein, to extend this approach to X-ray radiography. This work aims to evaluate with simulations if TOF scatter rejection can outperform ASGs for radiography.Approach GATE was used to simulate the radiography of a head and a torso and a water cylinder with bone inserts in a system with total timing jitters from 0 ps up to 500 ps full-width-at-half-maximum. The transparency of TOF scatter rejection to primary and scattered photons was evaluated as if it were a virtual ASG.Main results With a total timing jitter of 50 ps, TOF scatter rejection can reach a selectivity of 4.93 with a transparency to primary photons of 99%. Reducing the timing jitter close to 0 ps increases the selectivity up to 15.85 for a head and torso radiography, outperforming typical ASGs which usually have a selectivity from 2.5 to 10 with a transparency to primary photons from 50% to 70%.Significance This suggests that TOF scatter rejection may be suitable to replace ASGs in applications requiring lower radiation exposure if sufficiently low timing jitter is achieved.

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Section: Discussionmentioning

confidence: 99%

Time-of-flight scatter rejection in x-ray radiography

Rossignol,

Bélanger,

Gaudreault

et al. 2024

Phys. Med. Biol.

View full text Add to dashboard Cite

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Scatter estimation and correction using time-of-flight and deconvolution in x-ray medical imaging

Rossignol,

Bélanger,

Fromont

et al. 2024

Phys. Med. Biol.

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Objective Time-of-flight (TOF) scatter rejection requires a total timing jitter,including the detector timing jitter and the X-ray source’s pulses width, of 50 ps or lessto mitigate most of the effects of scattered photons in radiography and CT imaging.However, since the total contribution of the source and detector to the timing jittercan be retrieved during an acquisition with nothing between the source and detector,it can be demonstrated that this contribution may be partially removed to improvethe image quality.Approach A scatter correction method using iterative deconvolution of the measuredtime point-spread function estimates the number of scattered photons detected in eachpixel. To evaluate the quality of the estimation, GATE was used to simulate theradiography of a water cylinder with bone inserts, and a head and torso in a systemwith total timing jitters from 100 ps up to 500 ps full-width-at-half-maximum.Main results With a total timing jitter of 200 ps, 89% of the contrast degradationcaused by scattered photons was recovered in a head and torso radiography, comparedto 28% with a simple time threshold method. Corrected images using the estimationhave a percent root-mean square error between 2 and 14% in both phantoms withtiming jitters from 100 to 500 ps which is lower than the error achieved with scatterrejection alone at 100 ps.Significance TOF X-ray imaging has the potential to mitigate the effects of thescattering contribution and offers an alternative to anti-scatter grids that avoids lossof primary photons. Compare to simple TOF scatter rejection using only a threshold,the deconvolution estimation approach has lower requirements on both the source anddetector. These requirements are now within reach of state-of-the-art systems.

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Timing resolution in double-sided silicon photon-counting computed tomography detectors

Cited by 2 publications

References 32 publications

Time-of-flight scatter rejection in x-ray radiography

Time-of-flight scatter rejection in x-ray radiography

Scatter estimation and correction using time-of-flight and deconvolution in x-ray medical imaging

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