Geometric Measurements Research Articles

Laboratory tests, numerical simulations and design of press-braked S690 high strength steel channel sections under major-axis combined loading

Testing and numerical modelling have been conducted to investigate the cross-sectional behaviour and resistances of press-braked S690 high strength steel channel sections under combined compression and major-axis bending. The testing programme included initial local geometric imperfection measurements and twenty major-axis eccentric compression (combined loading) tests. The numerical modelling programme included a validation study, where finite element models were developed and validated against test results, and a series of parametric studies, where the developed finite element models were adopted to generate further numerical data over a wide range of cross-section dimensions and loading combinations. The obtained test and numerical data were used to evaluate the existing design interaction curves for press-braked S690 high strength steel channel sections under combined compression and major-axis bending, as specified in the European code, North American specification, and Australian/New Zealand standard. The evaluation results revealed that the codified design interaction curves led to conservative resistance predictions, owing to the linear shapes and inaccurate end points. Improved design interaction curves featuring more efficient shapes and anchored to more accurate end points were then proposed. The proposed design interaction curves were shown to result in more accurate resistance predictions for press-braked S690 high strength steel channel sections under combined compression and major-axis bending than their codified counterparts. The reliability of the proposed design interaction curves was confirmed by means of statistical analyses.

Direct-to-Implant, Prepectoral Breast Reconstruction: Geometric Breast Measurements and Changes at 2-Year Follow-Up.

Prepectoral breast reconstruction has recently experienced a resurgence in popularity. However, in direct-to-implant (DTI) reconstruction, there is no opportunity for capsular modifications before final implant insertion. Implant pocket and breast shape are thus maintained, initially, solely by the mastectomy skin flaps, and eventually, by attachments of the periprosthetic capsule. The present study aims to quantify changes in breast geometric measurements over time following DTI prepectoral breast reconstruction. A retrospective chart review was performed for patients who underwent bilateral prepectoral DTI reconstruction performed by a single surgeon from June of 2016 to January of 2018. Patients followed for more than 2 years were included. Yearly standardized frontal photographs were analyzed, and nipple-to-midline, sternal notch-to-nipple, and midclavicle-to-lower pole measurements were obtained. Patient demographics, operative details, and complications were documented. A total of 72 breasts (38 women) undergoing direct-to-implant, prepectoral breast reconstruction were included in the final analysis. Acellular dermal matrix was used in 56 breasts only (78.9%) for anterior coverage. The average change in nipple-to-midline distance after 2 years decreased by 0.41 cm (range, -2.00 to 2.97 cm), sternal notch-to-nipple distance decreased by 0.62 cm (range, -4.98 to 5.4 cm), and midclavicle-to-lower pole distance decreased 0.10 cm superiorly (range, -6.07 to 3.6 cm). In breasts that underwent postmastectomy radiation therapy, the average changes were -0.08, -0.43, and -0.56 cm, respectively. No patient in this cohort had severe malposition requiring further surgery. The present study provides insight into geometric breast measurements following prepectoral breast reconstruction at 2-year follow-up. The minimal breast shape changes observed demonstrate the feasibility of prepectoral DTI reconstruction with or without the use of acellular dermal matrix. Therapeutic, IV.

Vision measurement system for geometric parameters of tubing internal thread based on double-mirrored structured light.

Geometric parameter measurement of tubing internal thread is critical for oil pipeline safety. In response to the shortcomings of existing methods for measuring internal thread geometric parameters, such as low efficiency, poor accuracy, and poor accessibility, this paper proposes a vision system for measuring internal thread geometric parameters based on double-mirrored structured light. Compared to previous methods, our system can completely reproduce the internal thread tooth profiles and allows multi-parameter measurement in one setup. To establish the correlation between the structural and imaging parameters of the vision system, three-dimensional (3D) optical path models (OPMs) for the vision system considering the mirror effect of the prism is proposed, which extends the scope of the optical path analysis and provides a theoretical foundation for designing the structural parameters of the vision system. Moreover, modeling and three-step calibration methods for the vision system are proposed to realize high-accuracy restoration from the two-dimensional (2D) virtual image to the actual 3D tooth profiles. Finally, a vision measurement system is developed, and experiments are carried out to verify the accuracy and measure the three geometric parameters (i.e., taper, pitch, and tooth height) of typical internal threads. Based on the validation results using the reference system, the vision measurement accuracy and efficiency are 6.7 and 120 times that of the traditional system, which verifies the measurement effectiveness and accuracy of the vision system proposed in this paper.

COMBINATION OF THERMAL INFRARED IMAGES AND LASERSCANNING DATA FOR 3D THERMAL POINT CLOUD GENERATION ON BUILDINGS AND TREES

Abstract. The thermal infrared study of urban environments is of growing interest. It allows to observe the variations of surface temperatures on objects over time and therefore the microclimate at the scale of a street. To facilitate the analysis of thermal interactions between urban elements, it is necessary to provide a 3D visualization of the thermography of a street. For this purpose, 3D thermal models combining geometric and thermal infrared (TIR) measurements are required. The chosen format for 3D thermal models is a point cloud with a temperature attribute. In our approach, two types of urban components are considered: buildings and trees. The geometric data of each component are acquired with a static laser scanner and the surface temperature is acquired with a thermal handheld camera. For the building, the approach consists in georeferencing TIR images and colorize the point cloud by projection. For trees, the approach consists of the colorization of each laser scan prior to the registration. The spherical panoramic images acquired with the Terrestrial Laser Scanning (TLS) are used as references to automatically georeferenced the TIR and thus to save time. The 3D thermal models obtained highlight the impact of sunlight on buildings and trees. At building scale, this thermal representation also helps to emphasize thermal bridges, as well as the shadow generated by surrounding trees. At tree scale, this representation is useful for monitoring the temporal and spatial variability of trunk’s and leave’s temperatures. Obviously, the thermal models underline the impact of trees on the urban environment.

Press-braked ferritic stainless steel slender channel section beam–columns: Tests, simulations and design

This paper reports an experimental and numerical investigation into the buckling behaviour and resistance of press-braked ferritic stainless steel slender channel section beam–columns under combined compression and minor-axis bending moment. An experimental programme was firstly performed, including material coupon tests, initial global and local geometric imperfection measurements and ten beam–column tests. The experimental programme was followed by a numerical modelling programme, where finite element models were developed and validated against the experimental results and then adopted to conduct parametric studies to generate additional numerical data. Based on the obtained test and numerical data, the existing design interaction curves, as set out in the European code, American specification and Australian/New Zealand standard, were evaluated and found to result in conservative and scattered resistance predictions. An improved design interaction curve, anchored to more accurate end points and featuring more appropriate shape, was then developed and shown to offer more accurate and consistent resistance predictions for press-braked ferritic stainless steel slender channel section beam–columns over the codified design interaction curves. Statistical analyses were also performed to confirm the reliability of the new proposal.

Open-Circuit Fault Diagnosis Method for Grid-Connected Bidirectional T-Type Converter Based on Geometrical Similarity Measurement

Grid-connected bidirectional T-type converter (GBTC) is widely used in power generation, vehicle-to-grid, and other applications because of its bidirectional energy flow and superior performance. However, transistor open-circuit fault can cause serious output harmonics and even system outage. In this work, a novel open-circuit fault diagnosis method is proposed based on geometrical similarity measurement, which is suitable for the rectifier state and inverter state of the GBTC. Under healthy and faulty conditions, current paths and distortions are deeply analyzed. To evaluate the distortions, reference geometry vectors and current geometry vectors constructed from the grid angle and normalized currents are studied. Geometry features including vector triangle area, structural similarity, and contour similarity are used to measure the similarities among the vectors and carry out fault detection, fault phase location, and fault transistor location, respectively. Reasonable diagnostic thresholds are designed, and no additional sensor is needed. The robustness and effectiveness of the method are verified by experiment results.

Experimental and numerical investigations into S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures

This paper reports experimental and numerical investigations into S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures. A testing programme was firstly conducted and included heating, soaking and cooling of specimens as well as post-fire tensile coupon tests, initial local geometric imperfection measurements and stub column tests. Following the testing programme, a numerical modelling programme was conducted, where finite element models were developed and validated against the test results and then employed to perform parametric studies to generate further numerical data over a wide range of cross-section dimensions. Given that there are currently no available design standards for high strength steel structures after exposure to elevated temperatures, the relevant ambient temperature design rules, as set out in the European code, American specification and Australian standard, were assessed, using post-fire material properties, for their applicability to S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures. The assessment results revealed that the codified slenderness limits for plate elements in compression were generally accurate when used for cross-section classification of S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures up to 700 °C but conservative for higher temperatures beyond 700 °C. Moreover, the codified design rules were shown to provide accurate and consistent post-fire cross-section compression resistance predictions for S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures up to 700 °C but resulted in conservative predictions for higher temperatures beyond 700 °C.

Cepheids with giant companions: A new, abundant source of Cepheid astrophysics

AbstractWe present a progress report of our project aiming to increase the number of known Cepheids in double-lined binary (SB2) systems from six to 100 or more. This will allow us, among other goals, to accurately measure masses for a large sample of Cepheids. Currently, only six accurate Cepheid masses are available, which hinders our understanding of their physical properties and renders the Cepheid mass–luminosity relation poorly constrained. At the same time, Cepheids are widely used for essential measurements (e.g., extragalactic distances, the Hubble constant). To examine Cepheid period–luminosity relations, we selected as binary candidates Cepheids that are too bright for their periods. To date, we have confirmed 56 SB2 systems, including the detection of significant orbital motions of the components for 32. We identified systems with orbital periods up to five times shorter than the shortest reported period to date, as well as systems with mass ratios significantly different from unity (suggesting past merger events). Both features are essential to understand how multiplicity affects the formation and destruction of Cepheid progenitors and what effect this has on global Cepheid properties. We also present eight new systems composed of two Cepheids (only one such system was known before). Among confirmed SB2 Cepheids, there are also several wide-orbit systems. In the future, these may facilitate independent accurate geometric distance measurements to the Large and Small Magellanic Clouds.

Novel computed tomographic analysis demonstrates differences in patterns of bone mineral content between fracture configurations in distal condylar fractures of the third metacarpal/metatarsal bones in 97 Thoroughbred racehorses.

To evaluate bone mineral content patterns between fracture configurations using novel CT image analysis. CT images from 97 Thoroughbred racehorses with third metacarpal/tarsal condyle fractures provide the case population for analysis. Fractures were grouped by radiographic appearance. Image analysis objectively measured area of highly attenuating pixels (aHAP), areal density of highly attenuating pixels (dHAP) utilizing novel convex hull analysis, and subjective assessment of apparent attenuation intensity ranking (AAIR) for each fracture. Differences between fracture configuration groups were evaluated. Analysis of dHAP identified lower-density regions of highly attenuating pixels in propagating fractures and higher-density regions of highly attenuating pixels in unicortical fractures (P = .028). Complete and incomplete configurations were almost indistinguishable in dHAP (P = 1.000). The ratio of dHAP between fractured and nonfractured condyles revealed higher density gradients between condyles in unicortical (P = .040) and incomplete (P = .031) fractures than propagating fractures. Differences in patterns of bone mineral content were identified between propagating, bicortical (incomplete and complete), and unicortical fractures of third metacarpal/tarsal bone condyles. Computer-assisted geometric measurement of dHAP identified on CT images could help to assess fracture risk in equine athletes. This application may have greater relevance as standing CT screening becomes more available.

Synthesis of a Calibration-Free Visual Feedback Controller for an Inverted Pendulum Using a Fisheye Lens

This article considers the synthesis of feedback controllers for a class in which strong robust stability is required against sensing errors. The motivation dealing with this class arises from the stabilization problem of a cart-driven inverted pendulum by visual feedback control using a fisheye lens. While fisheye lenses guarantee a wide-angle of view, a large image distortion at off-center area is inevitable. Therefore this study first derives a geometric measurement model of a pendulum angle using a general fisheye lens model. A new design method for robust controllers for our problem is then proposed. Finally, a robust feedback controller that allows lens distortion is designed. The effectiveness of the controller based on the proposed model and the proposed design method is verified through numerical simulations and experiments.

Six-degree-of-freedom geometrical errors measurement system with compensation of laser beam drifts and installation errors for linear stage

In this paper, an optical measurement system is proposed to measure the six-degree-of-freedom (6DOF) geometrical errors of a linear stage, and the errors are analyzed by the interferometric method and the geometrical optics method. Among them, the interferometric method is mainly used for the position error analysis. This method can solve the problem that geometrical optics is limited by the size of the sensor in our previous system, and improve the measurement accuracy of the position error. The geometrical optics method is used for the error analysis of the remaining 5DOF geometrical errors to simplify the data acquisition time and calculation amount. In addition, this paper also proposes a methodology to compensate for laser beam drifts and installation errors of optical components. We use two sensors to measure the 4DOF laser beam drifts and add them into the proposed mathematical model to solve these errors. We also use sensitivity analysis to analyze the influence of each installation error of optical components and find out the installation errors that need to be considered. Then we bring them into the mathematical model and solved them with least square methods. Finally, we verify the feasibility of the proposed measurement system through repeated experiments and comparisons with a commercial interferometer and an electronic level.

Combined Acoustic Emission and Digital Image Correlation for Early Detection and Measurement of Fatigue Cracks in Rails and Train Parts under Dynamic Loading

Fatigue crack in rails and cyclic-loaded train parts is a contributory factor in multiple railroad accidents. We address the problem of crack detection and measurement at early stages, when total failure has not yet occurred. We propose to combine acoustic emission (AE) testing for prediction of crack growth with digital image correlation (DIC) for its accurate quantitative characterization. In this study, we imitated fatigue crack appearance and growth in samples of railway rail and two train parts by cyclic loading, and applied these two techniques for inspection. Experimental results clearly indicate the efficiency of AE in the early detection of fatigue cracks, and excellent DIC capabilities in terms of geometrical measurements. Combination of these techniques reveals a promising basis for real-time and non-destructive monitoring of rails and train parts.

Local stability of laser-welded stainless steel slender I-sections under combined loading

This paper presents a comprehensive experimental and numerical investigation into the local buckling behaviour of laser-welded stainless steel slender I-sections under combined compression and bending moment. A testing programme was firstly carried out, including initial local geometric imperfection measurements and eccentric compression tests on ten laser-welded stainless steel slender I-section stub column specimens. Following the testing programme, a numerical modelling programme was conducted. Finite element models were developed and validated against the test results, and then adopted to perform parametric studies to generate additional numerical data. The obtained test and numerical data were used to evaluate the applicability of the interaction curves in the European and American codes and the continuous strength method to laser-welded stainless steel slender I-sections under combined loading. The evaluation results generally show that the three sets of considered interaction curves offer adequate design accuracy for laser-welded stainless steel slender I-sections under combined compression and major-axis bending moment, but they yield unduly conservative and scattered resistance predictions for laser-welded stainless steel slender I-sections under minor-axis combined loading, owing principally to the conservative minor-axis bending end points. Finally, an improved design interaction curve for the minor-axis combined loading case was developed and shown to yield substantially more accurate and consistent resistance predictions for laser-welded stainless steel slender I-sections under minor-axis combined loading than the three considered design methods. The reliability of the new design interaction curve was confirmed based on a reliability study.

MRI data quality assessment for the RIN - Neuroimaging Network using the ACR phantoms

PurposeGenerating big-data is becoming imperative with the advent of machine learning. RIN-Neuroimaging Network addresses this need by developing harmonized protocols for multisite studies to identify quantitative MRI (qMRI) biomarkers for neurological diseases. In this context, image quality control (QC) is essential. Here, we present methods and results of how the RIN performs intra- and inter-site reproducibility of geometrical and image contrast parameters, demonstrating the relevance of such QC practice. MethodsAmerican College of Radiology (ACR) large and small phantoms were selected. Eighteen sites were equipped with a 3T scanner that differed by vendor, hardware/software versions, and receiver coils. The standard ACR protocol was optimized (in-plane voxel, post-processing filters, receiver bandwidth) and repeated monthly. Uniformity, ghosting, geometric accuracy, ellipse’s ratio, slice thickness, and high-contrast detectability tests were performed using an automatic QC script. ResultsMeasures were mostly within the ACR tolerance ranges for both T1- and T2-weighted acquisitions, for all scanners, regardless of vendor, coil, and signal transmission chain type. All measurements showed good reproducibility over time. Uniformity and slice thickness failed at some sites. Scanners that upgraded the signal transmission chain showed a decrease in geometric distortion along the slice encoding direction. Inter-vendor differences were observed in uniformity and geometric measurements along the slice encoding direction (i.e. ellipse’s ratio). ConclusionsUse of the ACR phantoms highlighted issues that triggered interventions to correct performance at some sites and to improve the longitudinal stability of the scanners. This is relevant for establishing precision levels for future multisite studies of qMRI biomarkers.

Post-fire behaviour and residual resistance of hot-rolled stainless steel channel sections under major-axis combined loading

This paper presents experimental and numerical investigations into the post-fire local buckling behaviour and residual resistance of hot-rolled stainless steel channel sections under combined compression and major-axis bending. The experimental investigation included heating and cooling of specimens as well as post-fire material testing, initial local geometric imperfection measurements and fourteen eccentric compression tests. A subsequent numerical investigation was performed, where finite element models were developed to simulate the test results and then used to conduct parametric studies to generate additional numerical data over a wide range of cross-section dimensions and loading combinations. Due to the lack of specific design standards for stainless steel structures after exposure to elevated temperatures, the relevant ambient temperature design interaction curves, as set out in the European code and American specification, were evaluated, using post-fire material properties, for their applicability to hot-rolled stainless steel channel sections under major-axis combined loading after exposure to elevated temperatures. The evaluation results revealed that the codified design interaction curves result in conservative post-fire residual resistance predictions, due to the conservative end points and inefficient shapes. Finally, new design interaction curves, with more accurate end points and efficient shapes, were proposed and shown to provide improved design accuracy than the codified design interaction curves for hot-rolled stainless steel channel sections under major-axis combined loading after exposure to elevated temperatures.

Hierarchical Clustering-Based Image Retrieval for Indoor Visual Localization

Visual localization is employed for indoor navigation and embedded in various applications, such as augmented reality and mixed reality. Image retrieval and geometrical measurement are the primary steps in visual localization, and the key to improving localization efficiency is to reduce the time consumption of the image retrieval. Therefore, a hierarchical clustering-based image-retrieval method is proposed to hierarchically organize an off-line image database, resulting in control of the time consumption of image retrieval within a reasonable range. The image database is hierarchically organized by two stages: scene-level clustering and sub-scene-level clustering. In scene-level clustering, an improved cumulative sum algorithm is proposed to detect change points and then group images by global features. On the basis of scene-level clustering, a feature tracking-based method is introduced to further group images into sub-scene-level clusters. An image retrieval algorithm with a backtracking mechanism is designed and applied for visual localization. In addition, a weighted KNN-based visual localization method is presented, and the estimated query position is solved by the Armijo–Goldstein algorithm. Experimental results indicate that the running time of image retrieval does not linearly increase with the size of image databases, which is beneficial to improving localization efficiency.

Flexural–torsional buckling of pin-ended press-braked S690 high strength steel angle section columns: Testing, modelling and design

This paper presents an experimental and numerical investigation into the flexural–torsional buckling behaviour and resistance of pin-ended press-braked S690 high strength steel angle section columns. An experimental programme was firstly conducted and included initial geometric imperfection measurements and twelve pin-ended column tests. The column test results, including the failure loads and deformations at the failure loads, load–mid-height torsional rotation curves and failure modes, were fully reported and discussed. The experimental programme was accompanied by a numerical modelling programme, where finite element models were developed and validated against the test results and then employed to perform parametric studies to expand the test data pool over a wider range of cross-section dimensions and member lengths. The obtained test and numerical data were then used to assess the relevant codified design rules, as provided in the European code, North American specification and Australian/New Zealand standard, and a DSM-based design approach. The assessment results revealed that all the codified design rules lead to excessively conservative and scattered resistance predictions for pin-ended press-braked S690 high strength steel angle section columns susceptible to flexural–torsional buckling, while the DSM-based design approach yields substantially improved resistance predictions, owing to the rational consideration of the length-dependent characteristic of flexural–torsional buckling and the interaction of flexural–torsional buckling with minor-axis flexural buckling.

X-ray computed tomography for advanced geometrical measurements of metal powders and enhanced surface topography analyses of additively manufactured parts

Metal powder has a significant influence on the quality and performance of laser powder bed fusion (LPBF) processes and products. A key requirement for metal powder is to have shape and size distribution designed to have adequate flowability, packing behavior and laser absorption, as well as to fabricate parts with acceptable density, surface finish and mechanical properties. Accurate three-dimensional (3D) characterizations of powder particles are fundamental to enable relevant research, for example on powder reuse and material waste reduction in LPBF. This work studies advanced measurement approaches, based on X-ray computed tomography (CT), for the 3D geometrical characterization of powder particles. The work includes comparisons with conventional powder characterization methods, considering different materials and powder morphologies. Results show the potential of the CT-based approaches to provide accurate and complete 3D powder geometrical measurements, and to exploit the obtained results for the enhancement of surface topography analyses and LPBF development. • Accurate 3D characterizations of metal powder are fundamental to improve the LPBF process. • Comparison of characterization methods for different materials and morphologies. • X-ray computed tomography enables a complete 3D geometrical characterization of powder. • CT powder characterization is exploited to enhance surface topography analyses and LPBF development.

GigaMVS: A Benchmark for Ultra-Large-Scale Gigapixel-Level 3D Reconstruction.

Multiview stereopsis (MVS) methods, which can reconstruct both the 3D geometry and texture from multiple images, have been rapidly developed and extensively investigated from the feature engineering methods to the data-driven ones. However, there is no dataset containing both the 3D geometry of large-scale scenes and high-resolution observations of small details to benchmark the algorithms. To this end, we present GigaMVS, the first gigapixel-image-based 3D reconstruction benchmark for ultra-large-scale scenes. The gigapixel images, with both wide field-of-view and high-resolution details, can clearly observe both the Palace-scale scene structure and Relievo-scale local details. The ground-truth geometry is captured by the laser scanner, which covers ultra-large-scale scenes with an average area of 8667 m 2 and a maximum area of 32007 m 2. Owing to the extremely large scale, complex occlusion, and gigapixel-level images, GigaMVS exposes problems that emerge from the poor scalability and efficiency of the existing MVS algorithms. We thoroughly investigate the state-of-the-art methods in terms of geometric and textural measurements, which point to the weakness of the existing methods and promising opportunities for future works. We believe that GigaMVS can benefit the community of 3D reconstruction and support the development of novel algorithms balancing robustness, scalability and accuracy.

Saturday, June 18, 20229:30 AM - 10:30 AM GPP06 Presentation Time: 9:30 AM: Image-Guided Cervical Cancer Brachytherapy: Summary of Consensus Recommendations from the Society for Abdominal Radiology and American Brachytherapy Society

<h3>Purpose</h3> To summarize recommendations regarding imaging guidance for cervical cancer brachytherapy implant placement from the Society of Abdominal Radiology (SAR) and American Brachytherapy Society (ABS). <h3>Materials and Methods</h3> A comprehensive literature search was conducted on PubMed for image-guided cervical cancer brachytherapy (BT) using radiography, ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). Original research studies were included for evaluation if they included sensitivity and specificity of tumor detection, complication rates, or additional quantitative imaging results directly related to brachytherapy, such as geometric distortion measurements. The literature review was evaluated by an expert panel of members from the Society for Abdominal Radiology (SAR) and American Brachytherapy Society (ABS). These data were analyzed to determine an overall level of evidence for each recommendation and the subsequent strength of each claim. <h3>Results</h3> Three-dimensional (3D) imaging is recommended for treatment planning whenever feasible due to the rate of toxicities ≥ Grade 3 decreasing from between 0-13.5% with 2D planning to 0-5.8% with 3D planning. US guidance is highly recommended for tandem selection and insertion to reduce uterine perforation rates from 2.3-34%/insertion without US-guidance to 0-1.4%/insertion with US. US-guided interstitial needle placement is feasible when post-implant 3D imaging is available for treatment planning. Post-implant CT is recommended over orthogonal radiography to reduce genitourinary and gastrointestinal complications and evaluate proper applicator positioning. Tumor visualization is optimal on T2-weighted (T2w) MRI, which also provides improved specificity for assessment of parametrial invasion. CT-based treatment planning should refer to prior MRI for high risk-clinical target volume (HR-CTV) contouring, when available. Treatment planning on MRI is highly recommended for HR-CTV delineation, and post-applicator imaging should include at minimum both a 2D sagittal T2w and 3D axial T2w fast spin echo-based sequence. <h3>Conclusions</h3> Imaging-guidance for cervical brachytherapy implant placement is now standard-of-care. 3D imaging with MRI is highly recommended for treatment planning purposes, although CT-based planning also results in fewer complications as compared to 2D planning techniques. Ultrasound is useful for applicator placement, but application to treatment planning is limited.