bluuebunny/crossref_metadata_2025 huggingface dataset:
An in vitro evaluation of cone-beam breast CT	methods
Authors: Zeng Kai , Fajardo Laurie L. , Kao Simon , Franken Edmund A. , Park Jeong Mi , Jing Zhenxue , Bai Er-wei , Wang Ge
Published: November 2024

Tomosynthesis was developed for mammography, especially breast cancer detection. However, its limited-angular range scan and resultant data incompleteness causes strong image artifacts and distortions. To address this problem, a hybrid imaging method was proposed in our previous work, which combines tomosynthesis and low-resolution CT into a single system to produce fewer artifacts and distortions at a similar dose level. The purpose of this paper is to evaluate the images reconstructed using the proposed method as compared with that using the conventional tomosynthesis method (ML-convex). For that purpose, the projection datasets are acquired in both numerical simulation and phantom experiments on our breast imaging platform. Three kinds of phantoms are used in our work, including a numerical phantom, a physical phantom and 8 in vitro phantoms made of breast specimens. In addition to visual comparison of the reconstructed images, we employ spatial resolution, image contrast, reconstruction error, and convergence rate to evaluate the results quantitatively. It is observed that the results from our method can achieve significantly higher spatial resolution, higher contrast, smaller reconstruction error and faster convergence rate. Besides, a reader study using 8 in vitro phantoms of breast specimens demonstrates the clinical potential of our method, which significantly outperforms the conventional tomosynthesis.
Retinal vessel enhancement and extraction based on directional	field
Authors: Chen Jian , Tian Jie , Tang Zichun , Xue Jian , Dai Yakang , Zheng Jian
Published: November 2024

In order to extract the low contrast vessels in retinal images, we propose a novel enhancement algorithm based on directional field and develop a robust retinal vessel extraction framework. The proposed enhancement algorithm can significantly improve the contrast of vasculature especially the slim vessels and low contrast vessels. In our framework, we first enhance the vasculature by the proposed enhancement algorithm, and extract the vessels from the enhanced image by a local extraction method. Secondly, we apply a series of modified top-hat transform to original image, and use a binary morphological reconstruction to extract the large size vessels. Finally, the whole vasculature is provided by an organic combination algorithm. The first step extracts the slim vessels and low contrast vessels well but misses some bifurcations and cross pixels. On the other hand, the second step preserves the bifurcations and cross pixels but misses some slim vessels and low contrast vessels. Therefore, the combination of the two methods can provide satisfactory extraction of vasculature. Experimental results show that our method outperforms existing algorithms in terms of sensitivity and accuracy when testing on 'DRIVE' and 'STARE' databases.
Human cognitive in X-ray diagnosis
Authors: Khalatbari Azadeh , Jenab Kouroush
Published: November 2024

In this paper, we study the reliability of X-ray imaging diagnosis considering human cognitive abilities (e.g., spatial orientation, visualization, line orientation, and perceptual speed), which play a vital role in the clinical decision making that requires classification systems. Also, this study explores sex influence on X-ray imaging diagnosis based on 176 X-ray images evaluated by 10 female radiologists and 8 male radiologists. Most related literature focuses on a binary classification (True or False) that uses a set of features derived from a given pattern. Also, they utilize the Receiver Operating Characteristics (ROC) analyses for assessing the accuracy of X-ray diagnosis. In this study, we use fuzzy benchmarking to construct fuzzy classification systems required for fuzzy medical decision-making and fuzzy reliability assessment. The proposed method differentiates the influence of human cognitive abilities and sex in X-ray diagnosis. The results from this study shows reliability of X-ray diagnosis is high and male radiologists excel in spatial and line orientation and female radiologists perform better in perceptual speed while both are competent in visualization ability.
X-ray excited optical luminescence of Mg-doped GaN
Authors: Lankinen A. , Svensk O. , Mattila M. , Tuomi T.O. , Lipsanen H. , McNally P.J. , O'Reilly L. , Paulmann C.
Published: November 2024

X-ray excited optical luminescence (XEOL) measurements of Mg-doped GaN were made using continuous spectrum of synchrotron radiation. The samples were grown by metalorganic vapour phase epitaxy (MOVPE) on α-Al $_{2}$ O $_{3}$ substrates. The electrical activation of the Mg dopants by thermal annealing was detected in the room-temperature XEOL spectra, but not in the ultraviolet light excitation low-temperature photoluminescence (PL) spectra. The better results of the X-ray excitation over the ultraviolet excitation PL is attributed to the larger penetration depth of X-rays in heavily Mg-doped GaN. The activation of the Mg dopants was confirmed using Hall measurements.
Interior reconstruction using the truncated Hilbert transform via	singular value decomposition
Authors: Yu Hengyong , Ye Yangbo , Wang Ge
Published: November 2024

The state-of-the-art technology for theoretically exact local computed tomography (CT) is to reconstruct an object function using the truncated Hilbert transform (THT) via the projection onto convex sets (POCS) method, which is iterative and computationally expensive. Here we propose to reconstruct the object function using the THT via singular value decomposition (SVD). First, we review the major steps of our algorithm. Then, we implement the proposed SVD method and perform numerical simulations. Our numerical results indicate that our approach runs two orders of magnitude faster than the iterative approach and produces an excellent region-of-interest (ROI) reconstruction that was previously impossible, demonstrating the feasibility of localized pre-clinical and clinical CT as a new direction for research on exact local image reconstruction. Finally, relevant issues are discussed.
Step by step analysis toward optimal MTF algorithm using an edge	test device
Authors: Donovan Molly , Zhang Da , Liu Hong
Published: November 2024

Comprehensive research focus on the use of an edge test device for accurate determination of the modulation transfer function (MTF) in x-ray imaging has resulted in the development of numerous edge processing algorithms. While the overall results of the relative algorithms have been compared, the individual steps within the algorithms have not previously been evaluated for similarities and differences that could significantly affect the resultant MTF. Therefore a step by step investigation to evaluate the alternative methods for each step separately holds the potential to provide insight into improving the overall algorithm by optimizing the method employed for each step. Thus this research study focused on comparing methods applicable for each step comprising the edge algorithm and providing a step by step guide for implementing the optimal algorithm based on given experimental conditions. In addition, new methods and combinations of methods were investigated in several of the algorithm steps, and were determined to provide comparable, if not superior, results to the existing methods. This included the use of different numbers of rows and columns in the region of interest (ROI) for determining the edge spread function (ESF), implementing a new three-step ESF filtering approach, and applying a median filter in both the ESF and line spread function (LSF) smoothing steps.
Non-astigmatic imaging with matched pairs of spherically bent	crystals or reflectors
Authors: Bitter M. , Hill K.W. , Jones F. , Scott S.
Published: November 2024

This paper defines the exact conditions for the application of a previously proposed, general, non-astigmatic, imaging scheme, consisting of a matched pair of spherically bent crystals or reflectors, to x rays. These conditions lead to two specific experimental arrangements, of which one can provide large magnifications. Potential applications include the x-ray diagnosis of laser-produced plasmas and x-ray imaging of, e.g., biological samples, using the highly monochromatic radiation at synchrotron light sources. The results obtained for x rays are, however, valid for a wide spectrum of the electromagnetic radiation so that, for instance, an application of one of the imaging schemes to lithography in the EUV wavelength range should also be possible, if the spherically bent crystals are replaced by appropriate spherical reflectors. Also described is the design of an x-ray crystal spectrometer, which meets the here defined, necessary requirements for the observation of the x-ray spectra of helium-like argon.
Dual helical cone-beam CT for inspecting large object
Authors: Zou Xiaobing , Zeng Li , Li Zongjian
Published: November 2024

In cone beam industrial computed tomography (ICT), it is often required to inspect the large object using flat detector. If traditional helical scanning is used, the field of view (FOV) is limited due to the size of flat detector. As an alternative, a dual helical cone-beam scanning is proposed in this paper. Before each helical scanning, x-ray source and flat detector are horizontally translated a given distance, and part of the object is covered by x-ray at each view angle. Then the object function is reconstructed by use of the improved helical FDK algorithm, which does not rebin projection data. Simulations validate that the images, which are reconstructed by proposed scanning mode and improved algorithm with small flat detector, are similar to those from the conventional helical scanning and FDK algorithm with large flat detector. The improved FDK algorithm is not sensitive to translation step. Furthermore, the proposed scanning mode can extend the radius of FOV up to at least 1.7 times.
ELID grinding characteristics of large stamping die for Wolter	mirror
Authors: Yin Shaohui , Ohmori Hitoshi , Liu Qing , Morita Shinnya , Chen Fengjun , Asami Muneaki , Fan Yufeng
Published: November 2024

An ultra-precision ELID grinding of large stamping dies of Wolter mirror for X-ray telescope was presented in this paper. The large stamping dies (S55C) with confocal paraboloid and hyperboloid was ground by ELID arc-enveloped grinding. In this ELID grinding system, cast iron fiber bonded (CIFB) diamond wheels were controlled by 3-dimentional ways to scan the work-piece and generate required surfaces. Its grinding characteristics such as attainable form accuracy, surface roughness were investigated. Furthermore, some measures to improve form accuracy were discussed and verified such as truing, compensating, and on-machine measuring.
Compressive sampling based interior reconstruction for dynamic	carbon nanotube micro-CT
Authors: Yu Hengyong , Cao Guohua , Burk Laurel , Lee Yueh , Lu Jianping , Santago Pete , Zhou Otto , Wang Ge
Published: November 2024

In the computed tomography (CT) field, one recent invention is the so-called carbon nanotube (CNT) based field emission x-ray technology. On the other hand, compressive sampling (CS) based interior tomography is a new innovation. Combining the strengths of these two novel subjects, we apply the interior tomography technique to local mouse cardiac imaging using respiration and cardiac gating with a CNT based micro-CT scanner. The major features of our method are: (1) it does not need exact prior knowledge inside an ROI; and (2) two orthogonal scout projections are employed to regularize the reconstruction. Both numerical simulations and in vivo mouse studies are performed to demonstrate the feasibility of our methodology.
Dosimetric characterization of a cone-beam O-arm™ imaging	system
Authors: Zhang Jie , Weir Victor , Fajardo Liliosa , Lin Jingying , Hsiung Hsiang , Ritenour E. Russell
Published: November 2024

This study compared patient dose and image quality of a mobile O-arm™ cone beam imaging system in the 3D scan acquisition mode to those of a 64 slice Computed Tomography (CT) imaging system. The investigation included patient dose, scattered radiation, and image quality measurements. The patient dose was measured using a 0.6cc Farmer ion chamber and 30cm long Computed Tomography (CT) head and body polymethylmethacrylate (PMMA) phantoms. The results show that under identical radiographic techniques (kVp, mAs, etc.) and with the same scan length, the O-arm™ in 3D scan acquisition mode delivers approximately half the radiation dose of a 64 slice CT scanner. Scattered radiation was measured at several locations around the O-arm™, at 1 m, 2 m and 3 m distances in 3D CT scan acquisition mode with a RadCal 10 × 5–180 pancake ion chamber using a 30 cm long CT body phantom as the source of scatter. Similar measurements were made in a 64 slice CT scanner. The data demonstrate that scattered radiation from the O-arm™ to personnel involved in a clinical procedure is comparable to that from a 64 slice CT scanner. Image quality was compared by exposing a CATPHAN phantom to comparable doses in both the O-arm™ and the CT scanner. The resultant images were then evaluated for modulation transfer function (MTF), high-contrast spatial resolution, and low contrast sensitivity for clinical application purpose. The O-arm™ shows comparable high contrast to the CT (7 lp/cm vs. 8 lp/cm). The low contrast in the O-arm™ is not visible due to fixed pattern noise. For image guided surgery applications where the location of a structure is emphasized over a survey of all image details, the O-arm™ has some advantages due to wide radiation beam coverage and lower patient dose. The image quality of the O-arm™ needs significant improvement for other clinical applications where high image quality is desired.
Computed tomography simulation using supertoroids
Authors: Hu Yingkang , Zhu Jiehua
Published: November 2024

Analytic simulation in computed tomography(CT) generates projection data for evaluating and improving CT image reconstruction algorithms and has played an important role in the research and development of x-ray CT. The simulation is desired to be as realistic as possible while the computation needs to be efficient and accurate. Early primitive equation-based phantoms such as Shepp-Logan and FORBILD use only boxes, cylinders, and quadrics to simulate body parts. The superquadrics have been used in Computer Graphics since 1980's, and in CT since 1990's. While their more complex shapes make them more realistic in simulation, the difficulties in solving their equations increase dramatically, which restricts their use, especially in ray-tracing and x-ray transform. Zhu et al. developed an algorithm for ray-intersecting the superellipsoid and used it to build a thorax phantom. No algorithms for ray-intersecting the supertoroid, however, are known up to now to the best of our knowledge. In this paper we propose such an algorithm and use it in computation of x-ray transform. The algorithm was tested by a phantom consisting of the top portion of vertebrae and a few ribs. Cone-beam data were produced from the phantom, and then used to reconstruct the phantom.
Fast finite Hilbert transform via DE quadrature scheme
Authors: Ji Changguo , Cui Yidong , Cao Wentian , Bao Shanglian
Published: November 2024

Purpose: The finite Hilbert transform (FHT) or inverse finite Hilbert transform (IFHT) is recently found to have some important applications in computerized tomography (CT) arena [1-6], where they are used to filter the derivatives of back-projected data in the chord-line based CT reconstruction algorithms. In this paper, we implemented, improved and validated a fast numerical solution to the FHT via a double exponential (DE) integration scheme. A same strategy can be used to compute IFHT.

Methods: To overcome the underflow of floating-point numbers, we first determined the range of variable transformation from the minimum positive value of single or double precision floating point number, the integration step can be further determined by the range of variable transformation and the integration level. Two functions with their known analytical FHTs are used to validate the implementation of the FHT via DE scheme. The surface map and 2D contour of the FHT transformation error with respect to integration level and the range of the variable transformation are used to numerically determine the optimal numbers for a fast FHT.

Results: Given a specific precision, the lowest integration level and the optimal range of variable transformation, which are used to transform a signal with a certain degree of fluctuation, can be numerically determined by the surface map and 2D contour of the standard deviation of transformation error. These two numbers can then be taken to efficiently compute the FHT for other signals with the same or less degree of fluctuation.

Conclusions: The FHT via DE scheme and the numerical method to determine the integration level and the range of transformation can be used for fast FHT in certain applications, such as data filtering in chord-line based CT reconstruction algorithms.
Accurate visual and haptic burring surgery simulation based on a	volumetric model
Authors: Tsai Ming-Dar , Hsieh Ming-Shium
Published: November 2024

Burring surgery is mainly implemented for fine or critical structures and widely used in orthopedic, oral and maxillofacial, ENT and neurosurgery departments to delicately cut or polish bones, joints or other tissues. This paper describes a volume manipulation method that extends a voxel with multiple values to represent accurate burred changes on tissue surfaces. Tissue surface reconstruction is implemented for the local burred surface to provide a real-time visual response. A burring force vector for a haptic response is calculated by detecting which parts of a bur contact tissue and summated from tissue removal loads on the contacted parts. A spine surgery example showed that rough surface features by gross cutting or smooth features by fine cutting can be clearly demonstrated and high haptic reality can be achieved by our simulations. The burring surgery simulator with the accurate visual and haptic responses can be an effective rehearsing and training tool.
Accurate 3D data stitching in circular cone-beam micro-CT
Authors: Ji Changguo
Published: November 2024

Purpose: In circular cone-beam microcomputed tomography (micro-CT), it is likely that the length of the Field of View (FOV) of a single acquisition is shorter than the total length of the object to be imaged, such as a rat in the case of preclinical application of micro-CT. This leads to multiple acquisitions using different bed positions with bed translations in between, which can be automated using a motorized bed stage. However, subtle mechanical inaccuracies can cause undesired effects when the reconstructed volumes of the different acquisitions are combined into one larger volume. In this paper, we develop an automated method for accurately stitching 3D computed tomography (CT) data using an image registration scheme, and validate this technique in a circular cone-beam micro-CT scanner.

Methods: The approach is based on precalculated spatial transformation matrices acquired by a calibration phantom with point markers at stitching positions. The spatial transformation between two adjacent subvolumes was calculated only once with a rigid-body matching algorithm. Once all transformation matrices are obtained, all subsequent reconstructed subvolumes imaged at these fixed positions can be stitched accurately, and efficiently using these precalculated matrices.

Results: We applied this method to real object/animal imaging in circular cone-beam micro-CT and compared the result with that obtained by stitching method calculated only by translation distances and CT voxel size. Both stitching errors calculated using point markers and stitched volumes of rigid object (a syringe) and small animal (a rat) illustrated the success of our proposed approach.

Conclusions: Preliminary experimental results demonstrate that "3D data stitching" using an image registration scheme provides a good solution to the voxel mismatch caused by limited FOV length in circular cone-beam micro-CT. This method can be extended to other tomography techniques which need to acquire data at fixed scanning positions.
Upper airway detection and visualization from cone beam image slices
Authors: Celenk Mehmet , Farrell Mike L. , Eren Haluk , Kumar K. , Singh G. Dave , Lozanoff Scott
Published: November 2024

This paper describes a method developed to assist in the detection and reconstruction of a three dimensional (3D) model of the human upper airway using cone beam computed tomography (CBCT) image slices and a 3D Gaussian smoothing kernel. The segmented and reconstructed volumetric airway is characterized by the corresponding three principal axes that are selected for viewing direction orientation via rotation and translation. These axes are derived using the 3D Principal Component Analysis (PCA) result of the rendered volume. To finely adjust the view and access airway, the major and minor axes of each slice are also computed using the two dimensional (2D) PCA in the respective planes. The exterior volume view is visualized in two modes, namely, a solid surface (volume details transparent to user) view and a nontransparent (volume detail accessible) view. This functionality provides an application driven use of the 3D airway in CBCT based anatomy studies. The extracted information may be useful as an imaging biomarker in the diagnostic assessment of patients with upper airway respiratory conditions such as obstructive sleep apnea, allergic rhinitis, and other related diseases; as well as planning orthopedic/orthodontic therapies.
Parallel magnetic resonance imaging using wavelet-based	multivariate regularization
Authors: Fang Sheng , Ying Kui , Cheng Jianping , Wang Shi , Zhang Jing , Xiao Zhikui , Shen Hao
Published: November 2024

The parallel imaging technique reduces the scan time at the expense of increased noise, due to its ill-conditioned system matrix. Tikhonov regularization has been proposed for SENSE to reduce the noise. However, Tikhonov regularized images suffer from residual aliasing aritfacts or image blurring when a low resolution prior image is used. This study used wavelet-based multivariate regularization to overcome this problem, while maintaining the computational efficiency of Tikhonov regularization. In this method, SENSE is formularized as a multilevel-structured problem in the wavelet domain. Regularization is adaptively performed based on the noise behavior for different levels and orientations throughout the wavelet domain. Both Tikhonov regularization and the present method are systematically evaluated using in vivo anatomical brain data and diffusion weighted brain data. Qualitative and quantitative results demonstrate the advantage of multivariate regularization over Tikhonov regularization in the presence of low resolution prior images. This method suits most parallel imaging applications, especially when a high-quality prior image is unavailable, such as diffusion weighed imaging.
Synchrotron-based scattered radiation from phantom materials used	in X-ray CT
Authors: Rao Donepudi V. , Swapna Medasani , Cesareo Roberto , Brunetti Antonio , Akatsuka Tako , Yuasa Tetsuya , Takeda Tohoru , Gigante Giovanni E.
Published: November 2024

Synchrotron-based scattered radiation form low-contrast phantom materials prepared from polyethylene, polystyrene, nylon, and Plexiglas is used as test objects in X-ray CT was examined with 8, 10 and 12 keV X-rays. These phantom materials of medical interest will contains varying proportions of low atomic number elements. The assessment will allowed us to estimate the fluorescence to total scattered radiation. Detected the fluorescence spectra and the associated scattered radiation from calcium hydroxyapatite phantom with 8, 10 and 12 keV synchrotron X-rays. Samples with Bonefil (60% and 70% of calcium hydroxyapatite) and Bone cream (35 ∼ 45% of calcium hydroxyapatite), were used. Utilized the X-ray micro-spectroscopy beamline facility, X27A, available at NSLS, BNL, USA. The primary beam with a spot size of the order of ∼ 10 μm, has been used for focusing. With this spatial resolution and high flux throuput, the synchrotron-based scattered radiation from the phantom materials were measured using a liquid-nitrogen-cooled 13-element energy-dispersive high-purity germanium detector.
Clinical implementation of an empirical method for electron output	factor determination
Authors: Johnson Daniel A. , Ahmad Salahuddin
Published: November 2024

The objective of this work has been to develop and implement an empirical calculation method for the determination of clinical electron output factors. Electron beams with various energies, field sizes, and source to surface distances using cutouts of varying radii were used to measure dose output at the depth of maximum dose in water. A 30 cm × 30 cm × 17.8 cm water equivalent phantom with a 0.125 cc cylindrical ion-chamber (PTW Model 31010) was used. The calculation model predicted the output factor as a product of the cone factor, radius dependent cutout factor, the effective source to surface distance factor and the area dependent aspect ratio factor. A comparative analysis of clinical cutout output factors, determined through both empirical calculation and direct measurement was performed to evaluate the clinical viability of the calculation method before its implementation in our clinic. A total of 643 output factors for 294 different cutout shapes were determined through both traditional measurement and predictive calculation. Predictive calculation differed from definitive measurement by at most 3.5% for all cases, a majority of cases falling within 1%. The method developed successfully predicts electron output factors on the basis of cutout geometry with accuracy better than 96% for all cases and better then 98% for most cases. This ability holds true for all practical SSD, electron energy, cone, and irregular shape combinations. The method has been clinically implemented and in use at our center since 2007.
A treatment planning comparison between proton beam therapy and	intensity-modulated x-ray therapy for recurrent nasopharyngeal carcinoma
Authors: Liu Su-Wen , Li Jia-Min , Chang Joe-Yujiao , Yu Jin-Ming , Chen Qing , Jiang Qian-An , Mu Xiang-Kui , Zhao Mei-Hong , Tian Ying , Wei Qing-Long
Published: November 2024

Background and purpose: A comparative treatment planning study was undertaken between proton beam therapy (PBT) and intensity-modulated x-ray therapy (IMXT) for patients with recurrent nasopharyngeal carcinoma (NPC), to assess the potential benefits and limitations of the two treatment modalities.

Materials and methods: We retrospectively analyzed seven patients with recurrent NPC treated at our proton center with PBT from 2004 to 2007. Eclipse proton treatment planning system and Eclipse inverse treatment planning system for IMXT were employed. For each patient, the IMXT plan was optimized with nine evenly spaced coplanar fields. Three coplanar beams and passive scattering mode were used for PBT. The dose prescription in cobalt Gray equivalent (CGE) for gross tumor volume (GTV) was 66CGE and for planning target volume (PTV), 62.7CGE. Dose-volume histograms (DVH) were used to evaluate the difference in dosimetric distributions for the target volume and the organs at risk (OARs).

Results: Optimal target volume coverage and similar target conformation were achieved in both PBT and IMXT. Median conformity index was 0.72 and 0.75 (p=0.15) and median inhomogeneity coefficient was 0.14 and 0.10 (p=0.08) for PBT and IMXT, respectively. Dose to OARs was significantly lower in PBT plans than IMXT. Median maximal dose to the brainstem was 27.89CGE(cobalt Gray equivalent) and 42.45Gy (p< 0.01), and the dose to 5% of the brainstem(D5) was 12.83CGE and 19.47Gy (p< 0.001 ), for PBT and IMXT, respectively. Median maximal dose to the spinal cord was 8.38CGE and 22.91Gy (p< 0.004), and the dose to 5% of the spinal cord was 2.18CGE and 13.62Gy (p< 0.001), for PBT and IMXT, respectively.

Conclusions: The use of PBT, when compared with IMXT, resulted in similar levels of tumor conformation. PBT, however, exposed the OARs to a significantly lower dose, effectively sparing the brainstem, spinal cord, optic nerve and chiasm, temporal lobes and parotid glands. The superior dose distributions possible with PBT should translate into reduced morbidity and improved quality of life.
Katsevich-type reconstruction for dual helical cone-beam CT
Authors: Zeng Li , Zou Xiaobing
Published: November 2024

This paper is about inspecting large and long object using dual helical cone-beam computed tomography (CT) and Katsevich-type reconstruction algorithm. Conventional cone-beam helical industrial CT imaging is based on the assumption that the entire cross-section of an object is illuminated with x-rays at each view angle. The field of view is limited by the width of planar detector. As an alternative, this paper developed a dual-helical scanning. When scanning at each helix, part of cross-section is covered by x-ray at each view angle. During reconstruction, Katsevich-type algorithm is applied, which does not rebin projection data. The algorithm is approximate, as it applies Hilbert transform on truncated projection. The reconstruction result is better than extended FDK algorithm, especially for large helical pitch.
Crack surface extraction of industrial CT volume data using FPIT	and planelet
Authors: Li Zongjian , Zeng Li , Zou Xiaobing , Xiang Caibing
Published: November 2024

As an advanced nondestructive testing (NDT) technology, industrial computed tomography (ICT) has been widely applied to diversified areas. In modern industry, ICT is especially useful for analyzing inner defects of complex and close work pieces. The common defects of work pieces include gas cavities, slag inclusions, cracks and shrinking cavities. Only cracks are often caused by fatigue usage. Precisely extracting a crack is important to estimate the remaining secure service time of the work piece. This paper presents a crack surface extraction method of ICT volume data based on finite plane integral transform (FPIT) and planelet. FPIT and planelet, as new methods of multiscale geometric analysis (MGA), have distinct discrimination for different plane singularities. Within the paper, firstly the definitions of FPIT and planelet are introduced. Secondly, after analyzing the components and relationship of planelet at monoscale, a fast performance of planelet transform is designed. Thirdly, the steps of the proposed crack surface extraction method are described. In numeric experiment, compared with the method of 3D facet model, C-V model and 3D wavelet respectively, the proposed method can extract the crack surface full and continuously, which,is robust to noise.
Unified reconstruction framework for multi-modal medical	imaging
Authors: Dong Di , Tian Jie , Dai Yakang , Yan Guorui , Yang Fei , Wu Ping
Published: November 2024

Various types of advanced imaging technologies have significantly improved the quality of medical care available to patients. Corresponding medical image reconstruction algorithms, especially 3D reconstruction, play an important role in disease diagnosis and treatment assessment. However, these increasing reconstruction methods are not implemented in a unified software framework, which brings along lots of disadvantages such as breaking connection of different modalities, lack of module reuse and inconvenience to method comparison. This paper discusses reconstruction process from the viewpoint of data flow and implements a free, accelerated, extensible Unified Reconstruction Software Framework (URSF). The software framework is an abstract solution that supports multi-modal image reconstruction. The goal of this framework is to capture the common processing work flow for different modalities and different methods, make the development of reconstruction for new devices much easier, and implement a set of popular reconstruction algorithms, so that it is convenient for researchers to compare against. The overall design and certain key technologies are introduced in detail. Presented experiment examples and practical applications commendably demonstrate the validity of this framework.
Synthetic aperture focusing for medical endoscopic ultrasonography
Authors: Chen Xiaodong , Li Ming , Li Yan , Wang Yi , Yu Daoyin
Published: November 2024

A new approach for synthetic aperture focusing (SAF) to enhance both signal to noise ratio (SNR) and resolution in endoscopic ultrasonography is presented in this paper. The technique uses the rotation feature of single element transducer probe, and transmits and receives the echoes at different time and locations during the rotary scanning. Based on theoretical simulation, axial and lateral matched-filters are developed according to the coded and linear frequency modulated characteristics of the echoes to implement axial and lateral compression. The effects of SNR and resolution enhancements by the new SAF approach are demonstrated by both Field II simulation and sample experiment. Data for 6 point targets are simulated and the performance of SAF is compared with those from conventional imaging method and Delay-and-Sum (DS) method. Pigskin samples are examined by a single element transducer at 8 MHz. The effects of sound speed errors and rotary scanning speed errors on both SNR and resolution are calculated to show the robustness of SAF algorithm. Both simulation and experimental results indicated that new SAF can improve SNR and resolution of ultrasound images by 9.38 dB and 51% respectively as compared with the conventional method. It therefore has potential for future clinical and research applications.
CT gradient image reconstruction directly from projections
Authors: Tang Shaojie , Mou Xuanqin , Wu Junfeng , Yan Hao , Yu Hengyong
Published: November 2024

An algorithm is proposed to directly reconstruct a CT gradient image in a region of interest(ROI). First, the central slice theorem is generalized and a differential constraint condition (DCC) is introduced in parallel-beam geometry. Then, an algorithm is developed to reconstruct the gradient images in both Cartesian and polar coordinate systems based on a two-step Hilbert transform method. Finally, the reconstruction algorithm is extended into the equi-distant fan-beam geometry. Meanwhile, a conditional truncation for projection data acquisition is permitted by using a one-dimensional(1-D) finite Hilbert transform in image domain. Because the reconstructed gradient image is in terms of local operator, it have a better performance in CT image analysis and other CT applications compared to the global Calderon operator in Lambda Tomography.
The perspectives of users and developers in designing and	developing O-arm imaging system
Authors: Park Moon Seok , Chung Chin Youb , Kwon Dae Gyu , Huh Young , Lee Kisung , Lee Kyoung Min
Published: November 2024

A questionnaire survey was performed to investigate the different knowledge of radiation exposure, awareness and expectation for O-arm imaging system between the users (orthopaedic surgeons) and the developers (engineers). A total of 93 orthopaedic surgeons and 19 engineers participated and answered the questionnaire consisting of 18 items designed for this study. The items were focused on knowlege, awareness, and expectation. Orthopaedic surgeons had higher scores for items of knowledge domains regarding radiation exposure than the engineers while the engineers were more sensitive to radiation hazards and adopted higher levels of radiation protection than orthopaedic surgeons in the awareness domain. Most engineers and orthopaedic surgeons answered that the requirements of diagnostic and intraoperative imaging systems differ. Image resolution, a low radiation exposure, and the time required for image acquisition was the top three requirements of O-arm selected by engineers. On the other hand, the top three requirements according to orthopaedic surgeons were; image resolution, expediency, and spatial occupancy. User requirements need to be reflected in developing O-arm along with basic requirements such as image resolution and low radiation exposure.
A 2D multiresolution image reconstruction method in X-ray computed	tomography
Authors: Costin Marius , Lazaro-Ponthus Delphine , Legoupil Samuel , Duvauchelle Philippe , Kaftandjian Valérie
Published: November 2024

We propose a multiresolution X-ray imaging method designed for non-destructive testing/evaluation (NDT/NDE) applications which can also be used for small animal imaging studies. Two sets of projections taken at different magnifications are combined and a multiresolution image is reconstructed. A geometrical relation is introduced in order to combine properly the two sets of data and the processing using wavelet transforms is described. The accuracy of the reconstruction procedure is verified through a comparison to the standard filtered backprojection (FBP) algorithm on simulated data.
Application of XANES profiles to X-ray spectromicroscopy for	biomedical specimens: Part I. Discrimination of macromolecules with sulfur atoms
Authors: Ito Atsushi , Inoue Takafumi , Takehara Kouji , Shimizu Norio , Kitajima Yoshinori , Shinohara Kunio
Published: November 2024

XANES spectra of biomacromolecules such as histone, hemoglobin or bovine serum albumin (BSA) were measured in transmission at the S-K absorption edge for comparison with those of sulfur containing low-molecular weight biomolecules with special reference to the dependence on the chemical environment of sulfur. The spectra of dry histone and hemoglobin exhibited a prominent peak at the same energy as that of cysteine and glutathione (GSH), while the BSA spectrum showed an additional peak at a lower energy, which coincided with that of cystine and glutathione disulfide (GSSG). XANES peaks were found at the same energy even in a mammalian cell dry pellet. Spectra in the hydrated state exhibited similar profiles except for a very slight shift of resonance peaks to the lower energy. These results indicate that XANES profiles could be applicable to the mapping of S-C and S-S bonds in dry/hydrated biological systems using a spectromicroscopic technique. In addition, mass absorption coefficients of GSH and GSSG were determined.
A novel method for detection and quantification of incomplete	penetration type flaws in weldments
Authors: Rathod Vijay R. , Anand R.S.
Published: November 2024

This paper presents an image processing approach to process incomplete penetration type flaws in radiographic images of the weld specimens considering morphological aspects of the image. In the present approach, radiographic weld image is processed to get the image with good contrast and reduced noise using image enhancement techniques like histogram equalization and noise filtering. This is followed by an effective edge detector such as Canny operator to find the edges of flaws, which are further used to segment the image to fix the boundaries. Image segmentation is performed using morphological approach implemented through dilation of similar boundaries and erosion of dissimilar and irrelevant boundaries decided on the basis of pixel characteristics. The incomplete penetration type flaws are clearly identifiable in the finally processed image, which is obtained by superimposing the segmented image over the original enhanced image. The experimental results proved that proposed approach can be used as a reliable method for automatic detection of incomplete penetration types of flaws in radiographic weld images.
Application of XANES profiles to X-ray spectromicroscopy for	biomedical specimens: Part II. Mapping oxidation state of cysteine in human	hair
Authors: Inoue Takafumi , Takehara Kouji , Shimizu Norio , Kitajima Yoshinori , Shinohara Kunio , Ito Atsushi
Published: November 2024

Human hair fibers are primarily composed of keratin protein, characterized by a very high content of cysteine, a sulfur-containing amino acid, which ordinarily forms cystine via a disulfide bond. It is known that some cystine residues are converted to cysteic acid during permanent waving or hair coloring, although details of their distribution and extent are still unclear. In this study, by using difference in XANES profiles of cystine and cysteic acid at the S-K absorption edge, the formation of cysteic acid was confirmed for homogenized samples of permed or bleached hair. Furthermore chemical mapping of cysteic acid was performed on hair-section samples with X-ray contact microscopy. The peripheral region, cuticle, in bleached hair showed the highest content of cysteic acid compared with the other parts, while permed hair showed relatively uniform distribution. This finding suggests that perming and bleaching damage hair by different mechanisms.
A new 3D information acquisition method of micro-drilling marks on	ancient perforated stone bead through micro-CT
Authors: Yang Min , Yang Yimin , Wang Changsui
Published: November 2024

Drilling is one of the most complex techniques for making ancient stone or jade implement or adornment. However, related research on ancient stone or jade drilling technology lags behind, for there are rare records or discovery of the ancient drilling tools. Drilling marks are very useful information for analysis and research of the ancient drilling techniques. The traditional information acquisition methods are very difficult to apply effectively on smaller perforations. In this paper, we introduced a new nondestructive method to solve the observation difficulty problem. The ancient bead was scanned by 3D-μCT system. Then through T-FDK algorithm, improved NL-means denoising algorithm and high accurate calibration, the 3D geometrical information of micro-drilling marks on outer and inner wall of the perforation were reconstructed. The experimental results proved that this method can provide key information for the analysis of the ancient stone drilling technique and ancient jade authentication.
Rapid analysis of iron concentrates by x-ray fluorescence	spectrometry with sol-gel sample preparation technology
Authors: Wang Fang , Li Zhong , Qiao Bo
Published: November 2024

A rapid method for the analysis of iron concentrates by gel sample preparation and x-ray fluorescence (XRF) spectrometry detection was developed. The solution digested by aqua regia was mixed with agarose, and then agarose was dissolved in the boiling solution and the mixture became quasi-solid gel at ambient temperature. The quasi-solid gel was detected by XRF. Analytical characteristics of the methods used were compared, and their reliability were tested against several certified reference materials of iron concentrates. The relative standard deviation was less than 0.3%.
A novel method for 3D crack edge extraction in CT volume data
Authors: Bi Bi , Zeng Li , Jiang Haina
Published: November 2024

To reduce time cost and improve the performance of edge extraction in CT volume data which is often in large size, we propose a novel method of 3D crack edge extraction using two fusion steps, one is fusion on Finite Line Integral Transform (FLIT) values in spatial directions called SD-FLIT and another is fusion on Local Binary Pattern (LBP) values on spatial planes called SP-LBP. By analyzing the S function of LBP operator, we find that value "0" of this function can describe the change between two equivalence planes. However, this property is sensitive to point difference, thus SD-FLIT is introduced to smooth noises and artifacts before the application of SP-LBP to extract 3D edge on binary volume data. Besides, fusions on directions and planes are aimed at extracting enough spatial information. Experimental results show that, owing to the sufficiency of information extraction and the simplicity of computation, our method can get continuous, thin and occlusive 3D edge, including the crack tip. Furthermore, it can be used to complicate volume data. Compared with 3D wavelet and Facet model, our method cost less time, saving at least 89% of that.
Effects on radiation oncology treatments involving various	neuromodulation devices
Authors: Gossman Michael S. , Paralikar Kunal J. , Hebb Adam O. , Wilkinson Jeffrey D. , Graves-Calhoun Alison R. , Lawson Raymond C. , Lopez Jeffrey P. , Powell James S.
Published: November 2024

Object: Where no society-based or manufacturer guidance on radiation limits to neuromodulation devices is available, this research provides the groundwork for neurosurgeons and radiation oncologists who rely on the computerized treatment plan clinically for cancer patients. The focus of the article is to characterize radiation parameters of attenuation and scatter when an incident therapeutic x-ray beam is directed upon them. At the time of this writing, manufacturers of Neuromodulation products do not recommend direct exposure of the device in the beam nor provide guidance for the maximum dose for these devices.

Methods: Ten neuromodulation models were chosen to represent the finite class of devices marketed by Medtronic before 2011. CT simulations permitted computer treatment modeling for dose distribution analysis as used routinely in radiation oncology for patients. Phantom case results were directly compared to actual clinical patient cases. Radiation detection measurements were then correlated to computational results. Where the x-ray beam passes through the device and is attenuated, dose reduction was identified with Varian Eclipse computer modeling for these posterior locations.

Results: Although the computer algorithm did not identify physical processes of side-scatter and back-scatter, these phenomena were proven by radiation measurement to occur. In general, the computer results underestimated the level of change seen by measurement.

Conclusions: For these implantable neurostimulators, the spread in dose changes were found to be −6.2% to −12.5% by attenuation, +1.7% to +3.8% by side-scatter, and +1.1% to +3.1% by back-scatter at 6 MV. At 18 MV, these findings were observed to be −1.4% to −7.0% by attenuation, +1.8% to 5.7% by side-scatter, and 0.8% to 2.7% by back-scatter. No pattern for the behavior of these phenomena was deduced to be a direct consequence of device size.
The effects of x-ray beam hardening on detective quantum	efficiency and radiation dose
Authors: Wong Molly Donovan , Wu Xizeng , Liu Hong
Published: November 2024

The goal of this preliminary study was to investigate the effects of x-ray beam hardening on the detective quantum efficiency (DQE) and the radiation dose of an inline x-ray imaging system. The ability to decrease the risk of harmful radiation to the patient without compromising the detection capability would more effectively balance the tradeoff between image quality and radiation dose, and therefore benefit the fields of diagnostic x-ray imaging, especially mammography. The DQE and the average glandular dose were both calculated under the same experimental conditions for a range of beam hardening levels, corresponding to no added beam hardening and two thicknesses each of Rhodium (Rh) and Molybdenum (Mo) filters. The dose calculation results demonstrate a reduction of 15% to 24% for the range of beam hardening levels. The comparison of all quantities comprising the DQE exhibit very close correlation between the results obtained without added beam hardening to the results corresponding to the range of beam hardening levels. For the specific experimental conditions utilized in this preliminary study, the results are an indication that the use of beam hardening holds the potential to reduce the radiation dose without decreasing the performance of the system. Future studies will seek to apply this method in a clinical environment and perform a comprehensive image quality evaluation, in an effort to further evaluate the potential of beam hardening to balance the tradeoff between dose and image quality.