Conventional X-ray Imaging Research Articles

A laboratory-based, low-energy, multi-modal x-ray microscope with user-defined resolution.

We report on the development of a low-energy x-ray phase-based microscope using intensity-modulation masks for single-shot retrieval of three contrast channels: transmission, refraction, and ultra-small-angle scattering or dark field. The retrieval method is based on beam tracking, an incoherent and phase-based imaging approach. We demonstrate that the spatial resolution of this imaging system does not depend on focal spot size nor detector pixel pitch, as opposed to conventional and propagation-based x-ray imaging, and it is only dependent on the mask aperture size. This result enables the development of a multi-resolution microscope where multi-scale samples can be explored on different length scales by adjusting only the mask aperture size, without other modifications. Additionally, we show an extended capability of the system to resolve periodic structures below the resolution limit imposed by the mask apertures, which potentially extends dark-field imaging beyond its conventional use.

X-Ray Dark-field radiography: Does this carry potential for diagnosing gout in exotic pets?

The aim of this study is to evaluate whether X-ray dark-field (DF) radiography is useful for the diagnosis of gout in birds and reptiles and whether this preclinical model could be helpful to establish this non-invasive imaging method in human medicine. A total of 18 limbs originating from 11 birds (7 different species) and 7 reptiles (4 different species) with and without suspected joint gout were measured using a grating-based X-ray dark-field setup and conventional X-ray examination, respectively. Each image acquisition generated a dark-field and a conventional absorption x-ray image. The results of the individual scans were compared with the results of a pathological examination and arthrocentesis. In 5 of the birds and 4 of the reptiles examined, gout was detected by pathologic examination. In each group, uric acid crystals were found in the joints of 3 animals by means of arthrocentesis. The uric acid crystals were detectable in 2 bird and 2 reptile limbs in the dark-field image. The study demonstrated that the urate crystals evoke a clearly visible dark field signal, whereas this was not the case in the conventional radiographs. The results obtained show that uric acid crystal detection using less invasive imaging methods in an animal model with birds and reptiles may expand gout diagnostics not only in veterinary medicine but also in human medicine and possibly replace arthrocentesis if a DF signal is detectable. Preclinical scanners which use X-ray dark-field and phase-contrast radiography already exist for hands and mammography.

An algorithmic diagnostic approach to scapholunate ligament injuries based on comparison of X-ray examinations and arthroscopy in 414 patients

Conventional X-ray imaging is usually the first diagnostic assessment after clinical examination in case of suspected scapholunate interosseous ligament (SLIL) injury. Nevertheless, there is no consensus on the norms of the scapholunate distance (SLD) or carpal angles. Therefore, we aimed to determine the utility of static and dynamic radiographs in the diagnostic of an SLIL injury in comparison with the reference standard arthroscopy. We retrospectively analyzed the preoperative X-ray series and surgical records of arthroscopies of 414 patients. Radiological assessment included conventional static X-rays in the posteroanterior (PA) projection, clenched fist views in ulnar and radial deviations, in which the SLD at the midportion of the scapholunate (SL) joint was measured. The scapholunate angle (SLA) and radiolunate angle (RLA) were measured on lateral wrist radiographs. Receiver operating characteristic (ROC) curves were created to determine possible cut-off points of the radiological indices for the diagnosis of SLIL injury. Further, a logistic regression with the parameters having the highest area under the curve (AUC) was calculated. We found that SLD in ulnar inclination (AUC= 0.774), SLD in PA projection (AUC=0.748), and SLA (AUC=0.737) had the highest diagnostic value. The AUC of the combination of these three parameters was 0.822 for all patients with any SLIL lesion and 0.850 for patients with SLIL lesions of 3-4 Geissler grade. Further investigation of SLIL pathology would be appropriate in the case of SLD in ulnar inclination of 2.7mm, SLD in PA projection of 1.9mm and SLA of 63°.

Coral extension rate analysis using computed axial tomography

Biology, geology, and paleoclimatology studies of coral reefs often rely on annual rates of corallite extension determined from cores of skeletal material recovered from scleractinian corals. To examine how corallite orientation within such cores may affect measured extension rates, we used high-resolution X-ray computed axial tomography (CT) to image a suite of short Orbicella faveolata cores from corals living in the northwest Gulf of Mexico. This nondestructive method enabled skeletal extension rates to be determined several ways: (1) along transects that cross individual slice/slab images, (2) along transects that cross both a 0.6-mm-thick CT slice and the corresponding conventional X-ray image from a 8.4-mm-thick slab of skeletal material, and (3) along transects that cross slices/slab images oriented at varied angles relative to a coral core’s longitudinal axis. Additionally, the true three-dimensional (3D) extension rates of individual corallites were determined and compared to the extension rates apparent on a two-dimensional (2D) slice/slab. Results suggest that differences between all methods are not statistically significant, confirming that the conventional extension rate methodology is suitable for studies if the core’s longitudinal axis is appropriately aligned with the growth axis of the corallites. Effects of core misalignment on extension rates measurement and the appearance of skeletal structures in 2D images are described, and the applicability of 3D imagery for investigations of coral polyp growth patterns and coral colony development is demonstrated.

Single-Shot Quantitative X-ray Imaging Using a Primary Modulator and Dual-Layer Detector: Simulation and Phantom Studies.

Conventional x-ray imaging provides little quantitative information due to scatter, beam hardening, and overlaying tissues. A single-shot quantitative x-ray imaging (SSQI) method was previously developed to quantify material-specific densities in x-ray imaging by combining the use of a primary modulator (PM) and dual-layer (DL) detector. The feasibility of this concept was demonstrated with simulations using an iterative patch-based method. In this work, we propose a new algorithm pipeline for SSQI that enables accurate quantification and high computational efficiency. The DL images contain four measurements that are obtained behind the unattenuated and partially attenuated regions of the PM of each layer. Using the low-frequency property of scatter and a pre-calibrated material decomposition (MD), four unknowns (i.e., two scatter images and two material-specific images) are jointly recovered by directly solving four equations given by the four measurements. We tested this algorithm in simulations and further demonstrated its efficacy on chest phantom experiments. Through simulation, we show that the new method for MD is robust against scatter. Its performance improves with smaller PM pitch size and smaller focal spot blur. The RMSE in material-specific images compared to ground truth reduces by 52%-84% versus without scatter correction. For our experimental study, we successfully separated soft tissue and bone. The computational time for processing each view was ~8 s without optimization. The reported results further strengthen the potential of SSQI for widespread adoption, leading to quantitative imaging not only for x-ray imaging but also for real-time image guidance or cone-beam CT.

Edge illumination X-ray phase contrast imaging for impact damage detection in CFRP

Carbon fibre reinforced polymer (CFRP) structures are widely used in the aerospace industry for their low weight and strong mechanical properties. However, they are prone to impact damage due to their brittle nature. Edge Illumination X-ray Phase Contrast imaging (EI XPCi), a novel, phase-based X-ray imaging technique, was compared against two established non-destructive evaluation methods for impact damage detection in CFRP plates. Planar EI XPCi was shown to allow the detection of a larger extent and more details of damage than both conventional X-ray imaging using contrast agents and ultrasonic immersion C-scans. However, both X-ray methods were unable to detect a delamination present in the plate, which was only observed from the ultrasonic C-scan. Planar EI XPCI has potential for rapid in-process scanning, where only 2D projection imaging is possible.

Flexible Plenoptic X-ray Microscopy

X-ray computed tomography (CT) is an invaluable technique for generating three-dimensional (3D) images of inert or living specimens. X-ray CT is used in many scientific, industrial, and societal fields. Compared to conventional 2D X-ray imaging, CT requires longer acquisition times because up to several thousand projections are required for reconstructing a single high-resolution 3D volume. Plenoptic imaging—an emerging technology in visible light field photography—highlights the potential of capturing quasi-3D information with a single exposure. Here, we show the first demonstration of a flexible plenoptic microscope operating with hard X-rays; it is used to computationally reconstruct images at different depths along the optical axis. The experimental results are consistent with the expected axial refocusing, precision, and spatial resolution. Thus, this proof-of-concept experiment opens the horizons to quasi-3D X-ray imaging, without sample rotation, with spatial resolution of a few hundred nanometres.

Development of a Micro Computed Tomography Scanner for Localization of Lesions and Assessment of the Margin Width of Resected Breast Specimens in the Operating Room

Objective: The objective of this study was to develop a micro-computed tomography (micro-CT) scanner machine and software dedicated to the localization of calcification in resected breast tissue specimens in a 3-dimensional image. The micro-CT scanner was designed to be used as a mobile machine, particularly for use in the operating room.Material and Methods: The system was designed to perform a 360-degree scan on a rotating table between the x-ray source and the detector sensor using a cone beam x-ray. The prototype was developed collaboratively between Prince of Songkla University (PSU) and the National Science and Technology Development Agency, Thailand (NSTDA). This was the first prototype for scanning specimens. The overall scan time and the image reconstruction was 5-10 minutes. The machine was tested for safety by PTEC (Electrical and Electronic Product Testing Center of NSTDA).Results: The specification of MiniiScan® and preliminary results of 3D image reconstruction of the resected breast tissue specimen by using the MiniiScan® are present in this report. The study evaluated specimens form 31 patients obtained from June 2016 through January 2018. The average scan time was 10.4 minutes. The turnaround time of the conventional technique was 27.9 minutes. The quality of the 3D images as evaluated by PSU staffs was superior to the conventional x-ray images done with the standard mammogram. The 3D images can display the correct position of calcification and a width between calcification to margins in all directional plane.Conclusion: The 3D images of the prototype intraoperative MiniiScan® scan were superior in quality to the standard mammogram, and had a quicker turnaround time for intraoperative application. Surgeons can use this machine in the operating room instead of relying on the conventional x-rays with a mammogram machine outside the operating theater.

In Vitro Preparation of Actively Maturing Bovine Articular Cartilage Explants for X-Ray Phase Contrast Imaging.

Understanding the mechanisms that underpin post-natal maturation of articular cartilage is of crucial importance for designing the next generation of tissue engineering strategies and potentially repairing diseased or damaged cartilage. In general, postnatal maturation of the articular cartilage, which is a wholesale change in collagen structure and function of the tissue to accommodate growth of the organism, occurs over a timescale ranging from months to years. Conversely dissolution of the structural organization of the cartilage that also occurs over long timescales is the hallmark of tissue degeneration. Our ability to study these biological processes in detail have been enhanced by the findings that growth factors can induce precocious in vitro maturation of immature articular cartilage. The developmental and disease related changes that occur in the joint involve bone and cartilage and an ability to co-image these tissues would significantly increase our understanding of their intertwined roles. The simultaneous visualization of soft tissue, cartilage and bone changes is nowadays a challenge to overcome for conventional preclinical imaging modalities used for the joint disease follow-up. Three-dimensional X-ray Phase-Contrast Imaging methods (PCI) have been under perpetual developments for 20 years due to high performance for imaging low density objects and their ability to provide additional information compared to conventional X-ray imaging. In this protocol we detail the procedure used in our experiments from biopsy of the cartilage, generation of in vitro matured cartilage to data analysis of image collected using X-ray phase contrast imaging.

Enhanced phase retrieval via deep concatenation networks for in-line X-ray phase contrast imaging

PurposeIn-line X-ray phase contrast imaging offers considerable additional information beyond that acquired from conventional absorption contrast X-ray imaging, showing promising potentials in clinical diagnosis, materials characterization and so on. Given the physically intractable factors tangled inside, conventional phase retrieval methods typically suffer from limited feasibility. A deep-learning-augmented reconstruction strategy is proposed to improve the phase retrieval in spatial resolution and noise compression. MethodsThe deep network is composed of a phase contrast refinement module and a phase retrieval module to stabilize and generalize the phase retrieval. The two modules are aggregated in a plug-and-play fashion with the final assembly finetuned using limited training data, essentially encouraging a semi-supervised training. Verification experiments were performed on simulated phase contrast images of histopathological images. The results were compared to those from conventional phase-attenuation duality method. ResultsThe deep-learning-augmented reconstruction strategy increases structural similarity and peak signal-to-noise ratio of phase retrieval result by more than 8% and 30%, and reduces root mean squared error by 46% compared with conventional phase-attenuation duality method. Conclusions: The pilot study of deep learning deployment in in-line X-ray phase-contrast imaging exhibit advantages against conventional methods in terms of spatial resolution and noise robustness.

Ранній ревматоїдний артрит без рентгенологічних ерозій: можливості МРТ-діагностики

У статті наведено результати клініко-променевого обстеження 65 пацієнтів із раннім ревматоїдним артритом із тривалістю суглобового синдрому до 12 місяців. Про­аналізовано частоту виявлення ерозій при стандартній рентгенографії кистей та магнітно-резонансній томографії (МРТ) залежно від клінічних і лабораторних особливостей. Розроблено стандартний протокол обстеження та послідовність оцінки зображень. МРТ є більш інформативним методом топічної діагностики ранніх артритів порівняно із стандартною рентгенографією. При ранньому ревматоїдному артриті МРТ дозволила діагностувати ерозивні зміни в суглобах у 36 пацієнтів із 65, що значуще більше, ніж при звичайному рентгенологічному дослідженні (2 пацієнти з 65). За допомогою МРТ ерозивні зміни в суглобах кистей було діагностовано за 12 місяців до їх виявлення на рентгенограмах, найбільш значущі відмінності у визначенні деструктивних змін спостерігаються в ділянці кісток зап’ястка та головок п’ясткових кісток. Частота виявлення ерозій при МРТ кисті корелювала із серопозитивністю за антитілами до цитрульованих білків та не залежала від активності процесу за DAS28.

Compressed Lateral and anteroposterior Anatomical Systematic Sequences \xabCLASS\xbb: compressed MRI sequences with assessed anatomical femoral and tibial ACL's footprints, a feasibility study

PurposeThis study's main objective is to assess the feasibility of processing the MRI information with identified ACL-footprints into 2D-images similar to a conventional anteroposterior and lateral X-Ray image of the knee. The secondary aim is to conduct specific measurements to assess the reliability and reproducibility. This study is a proof of concept of this technique.MethodsFive anonymised MRIs of a right knee were analysed. A orthopaedic knee surgeon performed the footprints identification. An ad-hoc software allowed a volumetric 3D image projection on a 2D anteroposterior and lateral view. The previously defined anatomical femoral and tibial footprints were precisely identified on these views. Several parameters were measured (e.g. coronal and sagittal ratio of tibial footprint, sagittal ratio of femoral footprint, femoral intercondylar notch roof angle, proximal tibial slope and others). The intraclass correlation coefficient (ICCs), including 95% confidence intervals (CIs), has been calculated to assess intraobserver reproducibility and interobserver reliability.ResultsFive MRI scans of a right knee have been assessed (three females, two males, mean age of 30.8 years old). Five 2D-"CLASS" have been created. The measured parameters showed a "substantial" to "almost perfect" reproducibility and an "almost perfect" reliability.ConclusionThis study confirmed the possibility of generating "CLASS" with the localised centroid of the femoral and tibial ACL footprints from a 3D volumetric model. "CLASS" also showed that these footprints were easily identified on standard anteroposterior and lateral X-Ray views of the same patient, thus allowing an individual identification of the anatomical femoral and tibial ACL's footprints.Level of evidenceLevel IV diagnostic study

Chronic Recurrent Multifocal Osteomyelitis (CRMO): An Unusual Presentation of Limb Pain

Chronic recurrent multifocal osteomyelitis (CRMO), known as nonbacterial osteomyelitis, is an autoinflammatory disease with periodic exacerbations, also known as nonbacterial osteomyelitis. It is a rare, noninfectious inflammatory disorder characterized by multifocal bony lesions with pain. Conventional X-ray and CT imaging show multiple osteolytic and sclerotic lesions in the affected limbs. It is a great challenge for pediatricians to diagnose this disease for its rarity. Early diagnosis, regular follow-up and appropriate treatments are mandatory to reduce morbidity and prevent these disease complications. We report here two cases of CRMO who presented with pain, swelling and redness of multiple sites of lower limbs from the Department of Paediatrics, Bangabandhu Sheikh Mujib Medical University (BSMMU). Clinical features, laboratory findings, and characteristic radiological findings were strongly suggestive of CRMO.

Handling of Incidents in the Clinical Application of Ionizing Radiation in Diagnostic and Interventional Radiology - a Multi-center Study.

According to the German legislation and regulation of radiation protection, i. e. Strahlenschutzgesetz und Strahlenschutzverordnung (StrlSchG and StrlSchV), which came into force on 31st December 2018, significant unintended or accidential exposures have to be reported to the competent authority. Furthermore, facilities have to implement measures to prevent and to recognize unintended or accidental exposures as well as to reduce their consequences. We developed a process to register incidents and tested its application in the framework of a multi-center-study. Over a period of 12 months, 16 institutions for x-ray diagnostics and interventions, documented their incidents. Documentation of the incidents was conducted using the software CIRSrad, which was developed, released for testing purposes and implemented in the frame of the study. Reporting criteria of the project were selected to be more sensitive compared to the legal criteria specifying "significant incidents". Reported incidents were evaluated after four, eight, and twelve months. Finally, all participating institutions were interviewed on their experience with the software and the correlated effort. The rate of reported incidents varied between institutions as well as between modalities. The majority of incidents were reported in conventional x-ray imaging, followed by computed tomography and therapeutic interventions. Incidents were attributed to several different causes, amongst others to the technical setup and patient positioning (19 %) and patient movement or insufficient cooperativeness of the patient (18 %). Most incidents were below corresponding thresholds stated in StrlSchV. The workload for documenting the incidents was rated as appropriate. It is possible to monitor and handle incidents complient with legal requirements with an acceptable effort. The number of reported incidents can be increased by frequent trainings on the detection and the processing workflow, on the software and legal regulation as well as by a transparent error handling within the institution. · The software CIRSrad was developed to enable the present study and as prototype platform for a future radiological incident management system.. · 586 exceedances of thresholds were recorded by 16 facilities in a period of one year.. · Frequent trainings of all users increase the number of reported cases.. · Müller BS, Singer J, Stamm G et al. Handling of Incidents in the Clinical Application of Ionizing Radiation in Diagnostic and Interventional Radiology - a Multi-center Study. Fortschr Röntgenstr 2022; 194: 400 - 408.

Dynamic X-ray elastography using a pulsed photocathode source

X-ray absorption of breast cancers and surrounding healthy tissue can be very similar, a situation that sometimes leads to missed cancers or false-positive diagnoses. To increase the accuracy of mammography and breast tomosynthesis, we describe dynamic X-ray elastography using a novel pulsed X-ray source. This new imaging modality provides both absorption and mechanical properties of the imaged material. We use a small acoustic speaker to vibrate the sample while a synchronously pulsed cold cathode X-ray source images the mechanical deformation. Using these stroboscopic images, we derive two-dimensional stiffness maps of the sample in addition to the conventional X-ray image. In a breast phantom composed of ZrO2 powder embedded in gel, dynamic elastography derived stiffness maps were able to discriminate a hard inclusion from surrounding material with a contrast-to-noise ratio (CNR) of 4.5. The CNR on the corresponding absorption image was 1.1. This demonstrates the feasibility of dynamic X-ray elastography with a synchronously pulsed X-ray source.

Development and assessment of an x-ray tube-based multi-beam x-ray scatter projection imaging system.

Coherent scatter x-ray imaging systems are sensitive to material structure and chemical composition, and generate soft-material images with contrast superior to conventional transmission x-ray imaging. For practicality in medical or security applications, the image data acquisition time should be <10 min. Our approach is a multi-beam projection imaging design. Previously, as a development stage, we implemented a synchrotron-based system with five coplanar pencil beams and continuous motion of the object. In the work reported here, we developed a more practical coherent scatter projection imaging system using a conventional x-ray tube source. The object is irradiated by an array of up to three rows by five columns of pencil beams, and motorized stages translate the object through the beams for step-and-shoot acquisition. For the same tube loading, broad spectrum beams, such as 110 kVp filtered with 2.25 mm Al, were found to provide a higher signal-difference-to-noise ratio between soft materials in scatter images than lower kVp, more heavily filtered beams that have a narrower, lower intensity spectrum. The shortest acquisition time for a 6.0 × 10.0 cm2 object with 6000 pixels was 8.8 min. The width of a sharp edge in the scatter image was consistent with the pencil beam diameter. Contrast-detail performance was similar to our synchrotron-based system. In this first x-ray tube-based system, for simplicity, the transmitted x rays are measured through attenuators using the same flat-panel detector that measures scattered x rays. As a result, the primary image quality was reduced.

Decompose kV projection using neural network for improved motion tracking in paraspinal SBRT.

On-treatment kV images have been used in tracking patient motion. One challenge of markerless motion tracking in paraspinal SBRT is the reduced contrast when the X-ray beam needs to pass through a large portion of the patient's body, for example, from the lateral direction. Besides, due to the spine's overlapping with the surrounding moving organs in the X-ray images, auto-registration could lead to potential errors. This work aims to automatically extract the spine component from the conventional 2D X-ray images, to achieve more robust and more accurate motion management. A ResNet generative adversarial network (ResNetGAN) consisting of one generator and one discriminator was developed to learn the mapping between 2D kV image and the reference spine digitally reconstructed radiograph (DRR). A tailored multi-channel multi-domain loss function was used to improve the quality of the decomposed spine image. The trained model took a 2D kV image as input and learned to generate the spine component of the X-ray image. The training dataset included 1347 2D kV thoracic and lumbar region X-ray images from 20 randomly selected patients, and the corresponding matched reference spine DRR. Another 226 2D kV images from the remaining four patients were used for evaluation. The resulted decomposed spine images and the original X-ray images were registered to the reference spine DRRs, to compare the spine tracking accuracy. The decomposed spine image had the mean peak signal-to-noise ratio (PSNR) and structural similarity index measure (SSIM) of 60.08 and 0.99, respectively, indicating the model retained and enhanced the spine structure information in the original 2D X-ray image. The decomposed spine image matching with the reference spine DRR had submillimeter accuracy (in mm) with a mean error of 0.13, 0.12, and a maximum of 0.58, 0.49 in the - and -directions (in the imager coordinates), respectively. The accuracy improvement is robust in all lateral and anteroposterior X-ray beam angles. We developed a deep learning-based approach to remove soft tissues in the kV image, leading to more accurate spine tracking in paraspinal SBRT.

Visual Evaluation of Image Quality of a Low Dose 2D/3D Slot Scanner Imaging System Compared to Two Conventional Digital Radiography X-ray Imaging Systems.

The purpose of this study was to assess the image quality of the low dose 2D/3D slot scanner (LDSS) imaging system compared to conventional digital radiography (DR) imaging systems. Visual image quality was assessed using the visual grading analysis (VGA) method. This method is a subjective approach that uses a human observer to evaluate and optimise radiographic images for different imaging technologies. Methods and materials: ten posterior-anterior (PA) and ten lateral (LAT) images of a chest anthropomorphic phantoms and a knee phantom were acquired by an LDSS imaging system and two conventional DR imaging systems. The images were shown in random order to three (chest) radiologists and three experienced (knee) radiographers, who scored the images against a number of criteria. Inter- and intraobserver agreement was assessed using Fleiss’ kappa and weighted kappa. Results: the statistical comparison of the agreement between the observers showed good interobserver agreement, with Fleiss’ kappa coefficients of 0.27–0.63 and 0.23–0.45 for the chest and knee protocols, respectively. Comparison of intraobserver agreement also showed good agreement with weighted kappa coefficients of 0.27–0.63 and 0.23–0.45 for the chest and knee protocols, respectively. The LDSS imaging system achieved significantly higher VGA image quality compared to the DR imaging systems in the AP and LAT chest protocols (p < 0.001). However, the LDSS imaging system achieved lower image quality than one DR system (p ≤ 0.016) and equivalent image quality to the other DR systems (p ≤ 0.27) in the knee protocol. The LDSS imaging system achieved effective dose savings of 33–52% for the chest protocol and 30–35% for the knee protocol compared with DR systems. Conclusions: this work has shown that the LDSS imaging system has the potential to acquire chest and knee images at diagnostic quality and at a lower effective dose than DR systems.

Computer-aided Detection of Lung Tumors in Chest X-ray Images Using a Bone Suppression Algorithm and A Deep Learning Framework

Detecting lung tumors in early stage by reading chest X-ray images is important for radical treatments of the disease. In order to decrease the risk of missed lung tumors, diagnosis support systems that can provide the accurate detection of lung tumors are in high demand, and the use of artificial intelligence with deep learning is one of the promising solutions. In our research, we aim to improve the accuracy of a deep learning-based system for detecting lung tumors by developing a bone suppression algorithm as a preprocessing for the machine-learning model. Our bone suppression algorithm was devised for conventional single-shot chest X-ray images, which do not rely on a specific type of imaging systems. 604 chest X-ray images were processed using the proposed algorithm and evaluated by combining it with a U-net deep learning model. The results showed that the bone suppression algorithm successfully improved the performance of the deep learning model to identify the location of lung tumors (Intersection over Union) from 0.085 (without the bone suppression algorithm) to 0.142, as well as the ability to classify the lung cancer (Area under Curve) that increased from 0.700 to 0.736. The bone suppression algorithm would be useful to improve the accuracy and the reliability of the deep learning-based diagnosis support systems for detecting lung cancer in mass medical examinations.

Quantitative Image Quality Metrics of the Low-Dose 2D/3D Slot Scanner Compared to Two Conventional Digital Radiography X-ray Imaging Systems.

The aim of this study was to determine the quantitative image quality metrics of the low-dose 2D/3D EOS slot scanner X-ray imaging system (LDSS) compared with conventional digital radiography (DR) X-ray imaging systems. The effective detective quantum efficiency (eDQE) and effective noise quantum equivalent (eNEQ) were measured using chest and knee protocols. Methods: A Nationwide Evaluation of X-ray Trends (NEXT) of a chest adult phantom and a PolyMethylmethacrylate (PMMA) phantom were used for the chest and knee protocols, respectively. Quantitative image quality metrics, including effective normalised noise power spectrum (eNNPS), effective modulation transfer function (eMTF), eDQE and eNEQ of the LDSS and DR imaging systems were assessed and compared. Results: In the chest acquisition, the LDSS imaging system achieved significantly higher eNEQ and eDQE than the DR imaging systems at lower and higher spatial frequencies (0.001 ≤ p ≤ 0.044). For the knee acquisition, the LDSS imaging system also achieved significantly higher eNEQ and eDQE than the DR imaging systems at lower and higher spatial frequencies (0.001 ≤ p ≤ 0.002). However, there was no significant difference in eNEQ and eDQE between DR systems 1 and 2 at lower and higher spatial frequencies (0.10 < p < 1.00) for either chest or knee protocols. Conclusion: The LDSS imaging system performed well compared to the DR systems. Thus, we have demonstrated that the LDSS imaging system has the potential to be used for clinical diagnostic purposes.