Combining scatter reduction and correction to improve image quality in cone‐beam computed tomography (CBCT)

Jin, Jian; Ren, Lei; Liu, Qiang; Kim, Jinkoo; Wen, Ning; Guan, Huaiqun; Movsas, Benjamin; Chetty, Indrin J.

doi:10.1118/1.3497272

Cited by 76 publications

(93 citation statements)

References 41 publications

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“…Although several techniques to correct the CBCT scatter artifacts have been proposed, e.g., using collimators, antiscatter grids and blockers, a standard approach remains unclear. [19][20][21][22][23][24] In this study, we investigated the feasibility of using deformable image registration () to create a modified planning CT that closely replicates the CBCT image as a basis of dose calculation for adaptive intensity modulated radiotherapy (IMRT) of the prostate. This method is hypothesized to be feasible due to the emergence of sophisticated  techniques capable of handling multimodal image registration.…”

Section: Introductionmentioning

confidence: 99%

Validation of a deformable image registration technique for cone beam CT‐based dose verification

et al. 2015

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Purpose: As radiation therapy evolves toward more adaptive techniques, image guidance plays an increasingly important role, not only in patient setup but also in monitoring the delivered dose and adapting the treatment to patient changes. This study aimed to validate a method for evaluation of delivered intensity modulated radiotherapy (IMRT) dose based on multimodal deformable image registration () for prostate treatments. Methods: A pelvic phantom was scanned with CT and cone-beam computed tomography (CBCT). Both images were digitally deformed using two realistic patient-based deformation fields. The original CT was then registered to the deformed CBCT resulting in a secondary deformed CT. The registration quality was assessed as the ability of the  method to recover the artificially induced deformations. The primary and secondary deformed CT images as well as vector fields were compared to evaluate the efficacy of the registration method and it's suitability to be used for dose calculation. , a free and open source software was used for deformable image registration. A B-spline algorithm with optimized parameters was used to achieve the best registration quality. Geometric image evaluation was performed through voxel-based Hounsfield unit (HU) and vector field comparison. For dosimetric evaluation, IMRT treatment plans were created and optimized on the original CT image and recomputed on the two warped images to be compared. The dose volume histograms were compared for the warped structures that were identical in both warped images. This procedure was repeated for the phantom with full, half full, and empty bladder. Results: The results indicated mean HU differences of up to 120 between registered and ground-truth deformed CT images. However, when the CBCT intensities were calibrated using a region of interest (ROI)-based calibration curve, these differences were reduced by up to 60%. Similarly, the mean differences in average vector field lengths decreased from 10.1 to 2.5 mm when CBCT was calibrated prior to registration. The results showed no dependence on the level of bladder filling. In comparison with the dose calculated on the primary deformed CT, differences in mean dose averaged over all organs were 0.2% and 3.9% for dose calculated on the secondary deformed CT with and without CBCT calibration, respectively, and 0.5% for dose calculated directly on the calibrated CBCT, for the full-bladder scenario. Gamma analysis for the distance to agreement of 2 mm and 2% of prescribed dose indicated a pass rate of 100% for both cases involving calibrated CBCT and on average 86% without CBCT calibration. Conclusions: Using deformable registration on the planning CT images to evaluate the IMRT dose based on daily CBCTs was found feasible. The proposed method will provide an accurate dose distribution using planning CT and pretreatment CBCT data, avoiding the additional uncertainties introduced by CBCT inhomogeneity and artifacts. This is a necessary initial step toward future imageguided adaptive ...

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Section: Introductionmentioning

confidence: 99%

Validation of a deformable image registration technique for cone beam CT‐based dose verification

et al. 2015

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“…(11) where represents the CT number of PMMA background, and represents the CT numbers of the materials in the insert and PMMA background, obtained from [24]. • Contrast to noise ratio (CNR) [25]: is a measure of the relation between contrast and noise of a VOI and the PMMA background.…”

Section: (7)mentioning

confidence: 99%

Noise Analysis in Computed Tomography (CT) Image Reconstruction using QR-Decomposition Algorithm

Iborra

Rodríguez-Álvarez

Soriano

et al. 2015

IEEE Trans. Nucl. Sci.

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“…When compared with other methods of tomographic imaging, CBCT is characterized by rapid volumetric image acquisition from single low radiation dose scan of the patient. [5][6][7][8] CBCT's accuracy and lack of superimposition makes it possible to measure the roof of the glenoid fossa and visualize the location of the soft tissue around the TMJ, which can offer a workable diagnosis and reduce the need for MRI. 9 Currently CBCT is most commonly used in the assessment of bony and dental pathologic conditions including fractures, maxillofacial deformity, fracture recognition, preoperative assessment of impacted tooth, TMJ disorders and in analysis of available bone for implant placement.…”

Section: Cone Beam Computed Tomography Technique (Cbct)mentioning

confidence: 99%

Evaluation of temporomandibular joint disorders using cone beam computed tomography

Kohli¹,

Sharma

Goel

et al. 2017

Int J Res Orthop

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Background: The aim of this study was to evaluate efficacy of segmental cone beam computed tomography (CBCT) in detecting bony changes in condyle and thickness of roof of glenoid fossa in temporomandibular joint (TMJ) disorders.Methods: The study group comprised of 10 temporomandibular disorders (TMD) patients of either sex between the age group of 20-60 years diagnosed as TMDs by clinical evaluation using the research diagnostic criteria was considered. After the clinical examination, radiographic investigations were carried out which included digital OPG, transcranial radiograph and CBCT scan. TMJ Evaluation included: (a) bony changes of the condyle (flattening, erosion, sclerosis, osteophytes, resorption); (b) joint space (normal, increased, reduced, bony contact between the condyle and the mandibular fossa); and (c) bony changes of mandibular fossa (normal, sclerosis, erosion, resorption). The radiographic findings were statistically analysed.Results: Significant difference between OPG, transcranial and CBCT were found for the presence of erosion (P =0.000), thickness of roof of glenoid fossa (P =0.000), deformed contour (P =0.001), joint space (P =0.011), subchondral sclerosis (P =0.011), irregularity of articular surface and eminence (P =0.000), flattening (P =0.050). Conclusions: Using CBCT as imaging technique in our study to detect osseous changes in the TMJ was proved to be effective as compared to the conventional radiographic techniques, the results achieved with CBCT was 100%.The results obtained in our study prove to be a full proof one and it seems to promise to go one step closer to detect progression and severity of the osseous changes in the condylar head and mandibular fossa in patients with TMDs.

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Combining scatter reduction and correction to improve image quality in cone‐beam computed tomography (CBCT)

Cited by 76 publications

References 41 publications

Validation of a deformable image registration technique for cone beam CT‐based dose verification

Validation of a deformable image registration technique for cone beam CT‐based dose verification

Noise Analysis in Computed Tomography (CT) Image Reconstruction using QR-Decomposition Algorithm

Evaluation of temporomandibular joint disorders using cone beam computed tomography

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