Cone beam computed tomography-the need for future guidance.
Ontology highlight
ABSTRACT:
SUBMITTER: Efird JT
PROVIDER: S-EPMC9641331 | biostudies-literature | 2022 Oct
REPOSITORIES: biostudies-literature
Publications
Cone beam computed tomography-the need for future guidance.
Efird Jimmy T JT Jindal Charulata C Podder Tarun K TK Kang Kylie H KH Biswas Tithi T
Journal of thoracic disease 20221001 10
Similar Datasets
Project description:Background and purposeMagnetic Resonance Imaging (MRI)-only planning workflows offer many advantages but raises challenges regarding image guidance. The study aimed to assess the viability of MRI to Cone Beam Computed Tomography (CBCT) based image guidance for MRI-only planning treatment workflows.Materials and methodsAn MRI matching training package was developed. Ten radiation therapists, with a range of clinical image guidance experience and experience with MRI, completed the training package prior to matching assessment. The matching assessment was performed on four match regions: prostate gold seed, prostate soft tissue, rectum/anal canal and gynaecological. Each match region consisted of five patients, with three CBCTs per patient, resulting in fifteen CBCTs for each match region. The ten radiation therapists performed the CBCT image matching to CT and to MRI for all regions and recorded the match values.ResultsThe median inter-observer variation for MRI-CBCT matching and CT-CBCT matching for all regions were within 2 mm and 1 degree. There was no statistically significant association in the inter-observer variation in mean match values and radiation therapist image guidance experience levels. There was no statistically significant association in inter-observer variation in mean match values for MRI experience levels for prostate soft tissue and gynaecological match regions, while there was a statistically significant difference for prostate gold seed and rectum match regions.ConclusionThe results of this study support the concept that with focussed training, an MRI to CBCT image guidance approach can be successfully implemented in a clinical planning workflow.
| S-EPMC10500022 | biostudies-literature
Project description:Movement of the target object during cone-beam computed tomography (CBCT) leads to motion blurring artifacts. The accuracy of manual image matching in image-guided radiotherapy depends on the image quality. We aimed to assess the accuracy of target position localization using free-breathing CBCT during stereotactic lung radiotherapy. The Vero4DRT linear accelerator device was used for the examinations. Reference point discrepancies between the MV X-ray beam and the CBCT system were calculated using a phantom device with a centrally mounted steel ball. The precision of manual image matching between the CBCT and the averaged intensity (AI) images restructured from four-dimensional CT (4DCT) was estimated with a respiratory motion phantom, as determined in evaluations by five independent operators. Reference point discrepancies between the MV X-ray beam and the CBCT image-guidance systems, categorized as left-right (LR), anterior-posterior (AP), and superior-inferior (SI), were 0.33 ± 0.09, 0.16 ± 0.07, and 0.05 ± 0.04 mm, respectively. The LR, AP, and SI values for residual errors from manual image matching were -0.03 ± 0.22, 0.07 ± 0.25, and -0.79 ± 0.68 mm, respectively. The accuracy of target position localization using the Vero4DRT system in our center was 1.07 ± 1.23 mm (2 SD). This study experimentally demonstrated the sufficient level of geometric accuracy using the free-breathing CBCT and the image-guidance system mounted on the Vero4DRT. However, the inter-observer variation and systematic localization error of image matching substantially affected the overall geometric accuracy. Therefore, when using the free-breathing CBCT images, careful consideration of image matching is especially important.
| S-EPMC4425686 | biostudies-literature
Project description:Background and purposeSpine stereotactic body radiotherapy (SBRT) requires a high degree of accuracy due to steep dose gradients close to the spinal cord. This study aimed to (1) evaluate intrafractional motion in spine SBRT utilizing flattening filter free (FFF) beam delivery and cone beam computed tomography (CBCT) image guidance and (2) evaluate if adding another CBCT acquisition and corrections prior to treatment improves the overall position accuracy.Materials and methodsIntrafractional motion was retrospectively analyzed for 78 fractions in 54 patients. All patients were immobilized with an evacuated cushion. Before treatment, a CBCT was acquired, a bony fusion with the planning CT was performed and translational and rotational errors were corrected. For 30 of the patients (39 fractions) acquisition of another CBCT and corrections were performed before treatment. A post treatment CBCT was acquired for all patients, and translational and rotational errors measured by fusion of the post treatment CBCT with the planning CT were recorded to calculate means and standard deviations (SDs).ResultsThe positional errors were significantly smaller in 4 out of 6 error values in the patient group treated with verification CBCT. In this group, translational and rotational SDs ranged from 0.5 to 0.6 mm and 0.3°, respectively. Corresponding values in the group treated without verification CBCT were 0.7-1.0 mm and 0.4-0.7°.ConclusionWith proper CBCT image guidance, patient immobilization and FFF-beam delivery, one can obtain very high patient position accuracy in spine SBRT. Inclusion of a verification CBCT prior to treatment increases the overall position accuracy.
| S-EPMC7807636 | biostudies-literature
Project description:ObjectiveTo present and validate an open-source fully automated landmark placement (ALICBCT) tool for cone-beam computed tomography scans.Materials and methodsOne hundred and forty-three large and medium field of view cone-beam computed tomography (CBCT) were used to train and test a novel approach, called ALICBCT that reformulates landmark detection as a classification problem through a virtual agent placed inside volumetric images. The landmark agents were trained to navigate in a multi-scale volumetric space to reach the estimated landmark position. The agent movements decision relies on a combination of DenseNet feature network and fully connected layers. For each CBCT, 32 ground truth landmark positions were identified by 2 clinician experts. After validation of the 32 landmarks, new models were trained to identify a total of 119 landmarks that are commonly used in clinical studies for the quantification of changes in bone morphology and tooth position.ResultsOur method achieved a high accuracy with an average of 1.54 ± 0.87 mm error for the 32 landmark positions with rare failures, taking an average of 4.2 second computation time to identify each landmark in one large 3D-CBCT scan using a conventional GPU.ConclusionThe ALICBCT algorithm is a robust automatic identification tool that has been deployed for clinical and research use as an extension in the 3D Slicer platform allowing continuous updates for increased precision.
| S-EPMC10440369 | biostudies-literature
Project description:Adaptive radiotherapy (ART) was introduced in the late 1990s to improve the accuracy and efficiency of therapy and minimize radiation-induced toxicities. ART combines multiple tools for imaging, assessing the need for adaptation, treatment planning, quality assurance, and has been utilized to monitor inter- or intra-fraction anatomical variations of the target and organs-at-risk (OARs). Ethos™ (Varian Medical Systems, Palo Alto, CA), a cone beam computed tomography (CBCT) based radiotherapy treatment system that uses artificial intelligence (AI) and machine learning to perform ART, was introduced in 2020. Since then, numerous studies have been done to examine the potential benefits of Ethos™ CBCT-guided ART compared to non-adaptive radiotherapy. This review will explore the current trends of Ethos™, including improved CBCT image quality, a feasible clinical workflow, daily automated contouring and treatment planning, and motion management. Nevertheless, evidence of clinical improvements with the use of Ethos™ are limited and is currently under investigation via clinical trials.
| S-EPMC10475190 | biostudies-literature
Project description:AimThe objective of this research was to measure the labial bone thickness (LBT) in relation to the 6 anterior maxillary teeth at different levels along the long axis and the distance between cementoenamel junction and bone crest (CEJ-BC) based on cone beam computed tomography (CBCT) scans retrieved from patients of Arab ethnicity and identify any association with patients' characteristics.Materials and methodsA total of 100 CBCT scans were evaluated by one calibrated examiner. The thickness of the labial bone was measured perpendicular to the long axis of the tooth at 1, 3, and 5 mm from the alveolar crest (LBT-1, LBT-3, and LBT-5, respectively) and CEJ-BC using a medical imaging viewer.ResultsCBCT scans of 58 female patients and 42 male patients with a mean age of 39.7 ± 9.5 years were included. A high variation of CEJ-BC was observed (range, 0.55-3.90 mm). Statistically significant higher CEJ-BC values were associated with men and increased age (>50 years). The overall means of LBT-1 were 0.76 ± 0.26, 0.79 ± 0.26, and 0.83 ± 0.37 mm; LBT-3: 0.92 ± 0.36, 1.05 ± 0.46, and 1.03 ± 0.48 mm; LBT-5: 1.17 ± 0.52, 0.80 ± 0.45, and 0.81 ± 0.40 mm for central incisors, lateral incisors, and canines, respectively. The LBT was <1 mm in 74.2% of all maxillary anterior teeth, with central incisors showing the highest predilection (85% with LBT <1 mm). No significant association between LBT and patient characteristics was observed.ConclusionsThe CEJ-BC distance is greater in men and increases with age, particularly in those aged 50 years and older. The LBT in the 6 maxillary anterior teeth is predominantly thin (<1 mm) and has no correlation to age or sex. An increased LBT was observed at a 3-mm level when compared with LBT-1 and LBT-5. Such variability should be taken into consideration when planning for implant placement.
| S-EPMC10023538 | biostudies-literature
Project description:ObjectivesTo investigate the validity and reliability of marginal bone level measurements on cone-beam computed tomography (CBCT) images of thin bony structures using various reconstruction techniques, two image resolutions, and two viewing modes.Materials and methodsCBCT and histologic measurements of the buccal and lingual aspects of 16 anterior mandibular teeth from 6 human specimens were compared. Multiplanar (MPR) and three-dimensional (3D) reconstructions, standard and high resolutions, and gray scale and inverted gray scale viewing modes were assessed.ResultsValidity of radiologic and histologic comparisons were highest using the standard protocol, MPR, and the inverted gray scale viewing mode (mean difference = 0.02 mm) and lowest using a high-resolution protocol and 3D-rendered images (mean difference = 1.10 mm). Mean differences were significant (P < .05) at the lingual surfaces for both reconstructions, viewing modes (MPR windows), and resolutions.ConclusionsVarying the reconstruction technique and viewing mode does not improve the observer's ability to visualize thin bony structures in the anterior mandibular region. The use of 3D-reconstructed images should be avoided when thin cortical borders are suspected. The small difference when using a high-resolution protocol is unjustified due to the higher radiation dose required. Previous studies have focused on technical parameters; the present study explores the next link in the imaging chain.
| S-EPMC10117211 | biostudies-literature
Project description:Different cone beam computed tomography (CBCT) protocols have shown promising results for imaging furcation defects. This study evaluates the suitability of low-dose (LD)-CBCT for this purpose. Fifty-nine furcation defects of nine upper and 16 lower molars in six human cadavers were measured by a high-dose (HD)-CBCT protocol, a LD-CBCT protocol, and a surgical protocol. HD-CBCT and LD-CBCT measurements were made twice by two investigators and were compared with the intrasurgical measurements, which served as the reference. Furcation defect volumes generated from HD-CBCT and LD-CBCT imaging were segmented by one rater. Cohen's kappa and intraclass correlation coefficient (ICC) values were calculated to determine intra- and interrater reliability. The level of significance was set at α = 0.05. In total, 59 furcation defects of nine upper and 16 lower human molars were assessed. Comparing CBCT furcation defect measurements with surgical measurements revealed a Cohen's kappa of 0.5975 (HD-and LD-CBCT), indicating moderate agreement. All furcation defects identified by HD-CBCT were also detected by LD-CBCT by both raters, resulting in a Cohen's kappa of 1. For interrater agreement, linear furcation defect measurements showed an ICC of 0.992 for HD-CBCT and 0.987 for LD-CBCT. The intrarater agreement was 0.994(r1)/0.992(r2) for HD-CBCT and 0.987(r1)/0.991(r2) for LD-CBCT. The intermodality agreement was 0.988(r1)/0.991(r2). Paired t-test showed no significant differences between HD-CBCT and LD-CBCT measurements. LD-CBCT is a precise and reliable method for detecting and measuring furcation defects in mandibular and maxillary molars in this experimental setting. It has the potential to improve treatment planning and treatment monitoring with a far lower radiation dose than conventional HD-CBCT.
| S-EPMC9043180 | biostudies-literature
Project description:Radiomics analysis extracts quantitative data (features) from medical images. These features could potentially reflect biological characteristics and act as imaging biomarkers within precision medicine. However, there is a lack of cross-comparison and validation of radiomics outputs which is paramount for clinical implementation. In this study, we compared radiomics outputs across two computed tomography (CT)-based preclinical scanners. Cone beam CT (CBCT) and µCT scans were acquired using different preclinical CT imaging platforms. The reproducibility of radiomics features on each scanner was assessed using a phantom across imaging energies (40 & 60 kVp) and segmentation volumes (44-238 mm3). Retrospective mouse scans were used to compare feature reliability across varying tissue densities (lung, heart, bone), scanners and after voxel size harmonisation. Reliable features had an intraclass correlation coefficient (ICC) > 0.8. First order and GLCM features were the most reliable on both scanners across different volumes. There was an inverse relationship between tissue density and feature reliability, with the highest number of features in lung (CBCT=580, µCT=734) and lowest in bone (CBCT=110, µCT=560). Comparable features for lung and heart tissues increased when voxel sizes were harmonised. We have identified tissue-specific preclinical radiomics signatures in mice for the lung (133), heart (35), and bone (15). Preclinical CBCT and µCT scans can be used for radiomics analysis to support the development of meaningful radiomics signatures. This study demonstrates the importance of standardisation and emphasises the need for multi-centre studies.
| S-EPMC11328005 | biostudies-literature
Project description: Not available
| S-EPMC11926433 | biostudies-literature