Transmission characteristics of a two dimensional antiscatter grid prototype for <scp>CBCT</scp>

Altunbas, Cem; Kavanagh, Brian D.; Alexeev, Timur; Miften, Moyed

doi:10.1002/mp.12346

Cited by 26 publications

(66 citation statements)

References 53 publications

(148 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…CNR improvements between 8% and 52% are achieved with the 2‐D ASG over 1‐D ASG results. Our previous studies suggested that the improvement in CNR is due to both higher primary transmission and lower scatter transmission . Other published studies indicated that, CNR may even be degraded by 1‐D ASG in low‐scatter imaging conditions due to lower primary transmission of 1‐D ASG …”

Section: Discussionmentioning

confidence: 87%

“…We demonstrated an improvement in primary transmission characteristics in projections acquired with the 2D‐ASG compared with projections acquired with 1D‐ASG. With respect to 1D‐ASG, projections acquired with 2D‐ASG displayed a factor of 3–6 lower scatter to primary ratio, and a factor of 1.3–1.4 improvement in CNR . In this letter, we present the first CBCT images produced from projections acquired using the 2D‐ASG prototype, and report on the improvement in CT number accuracy, reduction of image artifacts, and improvement in CNR.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Two‐dimensional antiscatter grid: A novel scatter rejection device for Cone‐beam computed tomography

et al. 2018

Self Cite

View full text Add to dashboard Cite

Purpose: Scattered radiation remains to be a major cause of image quality degradation in Flat Panel Detector (FPD)-based Cone-beam computed tomography (CBCT). We have been investigating a novel two-dimensional antiscatter grid (2D-ASG) concept to reduce scatter intensity, and hence improve CBCT image quality. We present the first CBCT imaging experiments performed with the 2D-ASG prototype, and demonstrate its efficacy in improving CBCT image quality. Methods: A 2D-ASG prototype with septa focused to x-ray source was additively manufactured from tungsten and mounted on a Varian TrueBeam CBCT system. CBCT projections of phantoms were acquired with an offset detector geometry using TrueBeam's "developer" mode. To minimize the effect of gantry flex, projections were gain corrected on angle-specific bases. CBCT images were reconstructed using a filtered backprojection algorithm and image quality improvement was quantified by measuring contrast-to-noise ratio (CNR) and CT number accuracy in images acquired with no antiscatter grid (NO-ASG), conventional one dimensional antiscatter grid (1D-ASG), and the 2D-ASG prototype. Results: A significant improvement in contrast resolution was achieved using our 2D-ASG prototype compared to results of 1D-ASG and NO-ASG acquisitions. Compared to NO-ASG and 1D-ASG experiments, the CNR of material inserts improved by as much as 86% and 54% respectively. Using 2D-ASG, CT number underestimation in water equivalent material section of the phantom was reduced by up to 325 HU when compared to NO-ASG and up to 179 HU when compared to 1D-ASG. Conclusion: We successfully performed the first CBCT imaging experiments with a 2D-ASG prototype. 2D-ASG provided significantly higher CT number accuracy, higher CNR, and diminished scatter-induced image artifacts in qualitative evaluations. We strongly believe that utilization of a 2D-ASG may potentially lead to better soft tissue visualization in CBCT and may enable novel clinical applications that require high CT number accuracy.

show abstract

Section: Discussionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Two‐dimensional antiscatter grid: A novel scatter rejection device for Cone‐beam computed tomography

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, controversial results are also found in the literature using other animal models where the evaluation of peri‐implant bone defect regeneration by means of CBCT was not accurate for sites providing bone width of <0.5 mm 39 . Research to reduce artifacts caused by titanium implants in CBCT images is emerging 45,48 …”

Section: Resultsmentioning

confidence: 99%

“…39 Research to reduce artifacts caused by titanium implants in CBCT images is emerging. 45,48 Kühl et al 42 reported high sensitivity of the CBCT scans when evaluating 1-and 3-mm defects. However, the specificity of CBCT is lower than that found when intraoral periapical radiographs are used.…”

Section: Use Of Cbct For Diagnosis and Treatment Outcome Assessmentmentioning

confidence: 99%

The Use of Cone‐Beam Computed Tomography in Management of Patients Requiring Dental Implants: An American Academy of Periodontology Best Evidence Review

Ríos

Borgnakke

Benavides

2017

Journal of Periodontology

View full text Add to dashboard Cite

The current available literature reflects an increased optimization of emerging CBCT imaging protocols and further highlights its diverse applications for dental implant therapy. This technology continues to be considered an advanced point-of-care imaging modality and should be used selectively as an adjunct to two-dimensional dental radiography. As with other ionizing radiation imaging modalities, CBCT imaging should be used only when the potential benefits to the patient outweigh the risks. Dental health care professionals should consider CBCT imaging only when they expect the diagnostic information yielded will lead to better patient care, enhanced patient safety, and ultimately facilitate a more predictable, optimal treatment outcome.

show abstract

“…To address this problem, two‐dimensional antiscatter grids (2DASG), a 2D array of through‐holes separated by tungsten septa, have been investigated recently. With respect to conventional ASGs, we have shown that 2DASG provides substantially better scatter rejection and primary x‐ray transmission performance, and therefore, has the potential to further improve CBCT image quality …”

Section: Introductionmentioning

confidence: 99%

A novel total variation based ring artifact suppression method for CBCT imaging with two‐dimensional antiscatter grids

et al. 2019

Self Cite

View full text Add to dashboard Cite

Purpose Two‐dimensional antiscatter grids (2DASG) for cone beam computed tomography (CBCT) is a new area of research to reduce scatter intensity, and consequently improve CBCT image quality. One of the challenges in implementation of 2DASGs is their septa shadows that are impinged on the projections. If these artifacts are not corrected, they may lead to ring artifacts in CBCT images. In this work, we present a novel method to suppress ring artifacts in FPD‐based CBCT images. Methods Briefly, our method first detects the locations of 2DASG’s septa shadows in projections and then, reduces projection pixel values in septa shadows iteratively until a residual‐based convergence criterion is met. To suppress the 2DASG’s septa shadows, we developed a total variation minimization (TVM) formulation, referred to as adaptive‐diffusive total variation minimization (adTVM), where the diffusivity regularization parameter was adaptively adjusted during each iteration based on the magnitude of the local pixel gradients. To test our method, we have acquired CBCT scans of phantoms using three 2DASG prototypes with different grid geometries. Projections were acquired with a linac mounted CBCT system, operated in offset detector geometry. These projections were then corrected in the following steps: first, projections were corrected using a gantry angle‐specific gain correction map; next, projections were corrected by applying our adTVM method. CBCT images were reconstructed using FDK filtered backprojection algorithm. To evaluate adTVM’s performance, pixel value statistics and contrast‐to‐noise ratio (CNR) were compared in CBCT images corrected with and without our adTVM method. Results Without our adTVM method, all three 2DASG prototypes introduced ring artifacts with varying intensities in CBCT images. With our method, significant reduction in ring artifacts was observed in all test cases. Standard deviation of CT numbers was reduced by 7–74% in uniform density phantom CBCT images, CNR was increased by 8–67%, and CT number accuracy of contrast objects embedded in the phantom was preserved. Conclusion We propose a new method to suppress ring artifacts caused by the 2DASG's septa shadows in CBCT images. Our initial investigations indicated that adTVM method could substantially reduce such ring artifacts while preserving CT number accuracy and maintaining good spatial resolution. Therefore, our method may potentially play an important role in enabling the implementation of 2DASGs in flat panel detector based CBCT systems.

show abstract

Transmission characteristics of a two dimensional antiscatter grid prototype for CBCT

Cited by 26 publications

References 53 publications

Two‐dimensional antiscatter grid: A novel scatter rejection device for Cone‐beam computed tomography

Two‐dimensional antiscatter grid: A novel scatter rejection device for Cone‐beam computed tomography

The Use of Cone‐Beam Computed Tomography in Management of Patients Requiring Dental Implants: An American Academy of Periodontology Best Evidence Review

A novel total variation based ring artifact suppression method for CBCT imaging with two‐dimensional antiscatter grids

Contact Info

Product

Resources

About