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Background: Given the fact that children are more sensitive to ionizing radiation than adults, with an increased risk of developing radiation-induced cancer, special care should be taken when they undergo X-ray examinations. The main aim of the current study was to determine Entrance Surface Dose (ESD) to pediatric patients arising from routine x-ray examination in the Radiology Department of Jimma University Specialized Hospital (JUSH)., Methods: Descriptive cross-sectional study was conducted on pediatric patients less than 15 years of age who visited to seek x-ray examinations in JUSH. In this study, chest (AP), skull (AP), Abdomen (AP) and Pelvic (AP) x-ray examinations were analyzed. Radiographic exposure factors were recorded in each examination. ESD was calculated using exposure parameters. The calculated ESD values were weighed against the Diagnostic Reference Level (DRL) recommended doses and similar published studies. Comparison was made among different age groups through mean comparison., Result: The obtained ESD values were mostly higher than the values in internationally published studies and DRL for all age groups. For chest AP, the mean ESD values were 1.82mGy which is higher than similar studies in Nigeria (0.642Mgy), Brazil (o.o62mGy) and NRPB (0.050mGy) for ages of 0-1 years., Conclusion: The higher pediatric patient dose obtained in this study is a further indicator that doses delivered to pediatric patients are not according to ALARA principle, and there is a need to optimize service and patients' radiation exposure in JUSH in particular and in Ethiopia in general.

The detection of spherical markers in x-ray projections is an important task in a variety of applications, e.g. geometric calibration and detector distortion correction. Therein, the projection of the sphere center on the detector is of particular interest as the used spherical beads are no ideal point-like objects. Only few methods have been proposed to estimate this respective position on the detector with sufficient accuracy and surrogate positions, e.g. the center of gravity, are used, impairing the results of subsequent algorithms. We propose to estimate the projection of the sphere center on the detector using a simulation-based method matching an artificial projection to the actual measurement. The proposed algorithm intrinsically corrects for all polychromatic effects included in the measurement and absent in the simulation by a polynomial which is estimated simultaneously. Furthermore, neither the acquisition geometry nor any object properties besides the fact that the object is of spherical shape need to be known to find the center of the bead. It is shown by simulations that the algorithm estimates the center projection with an error of less than [Formula: see text] of the detector pixel size in case of realistic noise levels and that the method is robust to the sphere material, sphere size, and acquisition parameters. A comparison to three reference methods using simulations and measurements indicates that the proposed method is an order of magnitude more accurate compared to these algorithms. The proposed method is an accurate algorithm to estimate the center of spherical markers in CT projections in the presence of polychromatic effects and noise.

Background: Patients usually undergo repeated X-ray examinations after their initial X-ray radiographs are rejected due to poor image quality. This subjects the patients to excess radiation exposure and extra cost.It is therefore investigating the magnitude and causes of reject is mandatory. This study aimed to assess the reject rate of X-ray films and its economic implication in order to obtain information for further recommendations on image quality, cost and radiation exposure., Method: A cross-sectional study approaches was employed. Reject rate was measured for two x-rays in the department across all plain x-ray films examinations using a structured format on which relevant data for reject were recorded by investigators. The results were then collected and entered into a database for analysis., Result: Reject rate and cause of reject were measured across all plane x-ray examinations for the hospital. From a total of 6563 exposed films, 16.85% were rejected. This leads to economic waste of 24,721.99 ETB, or 17.8% of a total cost in 4month period and increase in radiation dose to both patients and staff., Conclusion: The findings from this study show that both the overall reject rate and individual reject rate were higher than the accepted range which could be due to machine fault, operator's technical limitations, or absence of quality control program in the department. We recommend that regular quality assurance and quality control procedure which are well documented should be established in the department.

Imaging of secondary electron bremsstrahlung x-ray emitted during proton irradiation is a possible method for measurement of the proton beam distribution in phantom. However, it is not clear that the method is used for range estimation of protons. For this purpose, we developed a low-energy x-ray camera and conducted imaging of the bremsstrahlung x-ray produced during irradiation of proton beams. We used a 20 mm  ×  20 mm  ×  1 mm finely grooved GAGG scintillator that was optically coupled to a one-inch square high quantum efficiency (HQE)-type position-sensitive photomultiplier tube to form an imaging detector. The imaging detector was encased in a 2 cm-thick tungsten container, and a pinhole collimator was attached to its camera head. After performance of the camera was evaluated, secondary electron bremsstrahlung x-ray imaging was conducted during irradiation of the proton beams for three different proton energies, and the results were compared with Monte Carlo simulation as well as calculated value. The system spatial resolution and sensitivity of the developed x-ray camera with 1.5 mm-diameter pinhole collimator were estimated to be 32 mm FWHM and 5.2  ×  10 -7 for ~35 keV x-ray photons at 100 cm from the collimator surface, respectively. We could image the proton beam tracks by measuring the secondary electron bremsstrahlung x-ray during irradiation of the proton beams, and the ranges for different proton energies could be estimated from the images. The measured ranges from the images were well matched with the Monte Carlo simulation, and slightly smaller than the calculated values. We confirmed that the imaging of the secondary electron bremsstrahlung x-ray emitted during proton irradiation with the developed x-ray camera has the potential to be a new tool for proton range estimations.

Quality Problem or Issue: To assess the quality of radiological examinations (REs) and to evaluate the effectiveness of a participatory continuous improvement approach to ensure best practices in a Portuguese hospital imaging department., Initial Assessment: At baseline, we found 232 (10.2%) non-compliances, mostly related to the criteria image centering and framing in chest radiography (CXR), proper use of radiological protection equipment in other conventional RE (CR) and X-ray beam collimation (CXR/CR)., Choice of Solution: A baseline and three consecutive evaluations of the RE quality were conducted. Each assessment was followed by participatory focused interventions for improvement., Implementation: For each evaluation, we selected a random sample (n = 60) of cases for four types of examination (total n = 240 for each assessment, and 960 for the whole project). Both the building of quality criteria and the design of interventions for improvement were participatory, involving the radiology technicians. Estimates of criteria compliance were calculated with 95% confidence intervals. The statistical significance of absolute and relative improvements was tested using one-tail z-tests., Evaluation: After the intervention, non-compliances decreased to 48 (2.1%). Compliance estimates improved in 25 of 38 criteria assessed, with statistical significance for 5 criteria in CXR and 3 in CR and digestive examination., Lessons Learned: The internal participatory approach enabled the identification of existing quality problems and, by focusing on the more frequent quality defects, was effective in improving the quality of RE., (© The Author 2017. Published by Oxford University Press in association with the International Society for Quality in Health Care. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com)

Purpose: In grating-based x-ray multi-contrast imaging, signals of three contrast mechanisms-absorption contrast, differential phase contrast (DPC), and dark-field contrast-can be estimated from the same set of acquired data. The estimated signals, N 0 (related to absorption), N 1 (related to dark-field), and φ (related to DPC) may be intrinsically biased. However, it is yet unclear how large these biases are and how the data acquisition parameters affect the biases in the extracted signals. The purpose of this paper was to address these questions., Methods: The biases of the extracted signals (i.e., N 0 , N 1 and φ) were theoretically studied for a well-known signal estimation method. Experimental data acquired from a grating-based x-ray multi-contrast benchtop imaging system with a photon counting detector were used to validate the theoretical results for the signal biases of the three contrast mechanisms., Results: Both theoretical and experimental studies showed the following results: (1) The bias of signal estimation for the absorption contrast signal is zero; (2) The bias of signal estimation for N 1 is inversely proportional to the number of phase steps and to the average fringe visibility of the grating interferometer, but the ratio between the bias and the signal level (i.e., the relative bias) is independent of the number of phase steps; (3) The bias of signal estimation for φ depends on the mean DPC signal level, the total exposure level of the multi-contrast data acquisition, and the mean fringe visibility of the interferometer., Conclusions: In grating-based x-ray multi-contrast imaging, the estimated absorption contrast signal is unbiased; the estimated dark-field contrast signal is biased, but the relative bias is only dependent on the mean fringe visibility of the interferometer and the exposure level. The estimated DPC signal may be biased, and the bias level depends on the mean signal level, the exposure level, and the interferometer performance., (© 2017 American Association of Physicists in Medicine.)

Background: The Australian Synchrotron Imaging and Medical Beamline (IMBL) was designed as the world's widest synchrotron X-ray beam, enabling both clinical imaging and therapeutic applications for humans as well as the imaging of large animal models. Our group is developing methods for imaging the airways of newly developed CF animal models that display human-like lung disease, such as the CF pig, and we expect that the IMBL can be utilised to image airways in animals of this size., Methods: This study utilised samples of excised tracheal tissue to assess the feasibility, logistics and protocols required for airway imaging in large animal models such as pigs and sheep at the IMBL. We designed an image processing algorithm to automatically track and quantify the tracheal mucociliary transport (MCT) behaviour of 103 μm diameter high refractive index (HRI) glass bead marker particles deposited onto the surface of freshly-excised normal sheep and pig tracheae, and assessed the effects of airway rehydrating aerosols., Results: We successfully accessed and used scavenged tracheal tissue, identified the minimum bead size that is visible using our chosen imaging setup, verified that MCT could be visualised, and that our automated tracking algorithm could quantify particle motion. The imaging sequences show particles propelled by cilia, against gravity, up the airway surface, within a well-defined range of clearance speeds and with examples of 'clumping' behaviour that is consistent with the in vivo capture and mucus-driven transport of particles., Conclusion: This study demonstrated that the wide beam at the IMBL is suitable for imaging MCT in ex vivo tissue samples. We are now transitioning to in vivo imaging of MCT in live pigs, utilising higher X-ray energies and shorter exposures to minimise motion blur.

A pilot study was carried out involving six radiology centres across the state of Tasmania, Australia, with two main goals. First, to compare the choice of exposure factors used by each centre for four common paediatric projections of a 'standard' infant, 5-, 10- and 15-year-old patients. Second, to measure dose area product (DAP) at each radiology centre using the factors obtained and compare it against published diagnostic reference levels (DRLs). Significant variation was observed between the six radiology centres studied which has been attributed to the variability in exposure factors provided by the centres. Notably, the measured DAP values in the case of infant and 5-year-old patients were observed to be significantly lower than the published reference DAP DRLs. While significantly higher exposure factors have been observed for 15-year-old patients as illustrated in measured DAP values., (© The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Accounting for about 1.5 million deaths annually, lung cancer is the prevailing cause of cancer deaths worldwide, mostly associated with long-term smoking effects. Numerous small-animal studies are performed currently in order to better understand the pathogenesis of the disease and to develop treatment strategies. Within this letter, we propose to exploit X-ray dark-field imaging as a novel diagnostic tool for the detection of lung cancer on projection radiographs. Here, we demonstrate in living mice bearing lung tumors, that X-ray dark-field radiography provides significantly improved lung tumor detection rates without increasing the number of false-positives, especially in the case of small and superimposed nodules, when compared to conventional absorption-based imaging. While this method still needs to be adapted to larger mammals and finally humans, the technique presented here can already serve as a valuable tool in evaluating novel lung cancer therapies, tested in mice and other small animal models.

Proton beam therapy benefits from the Bragg peak and delivers highly conformal dose distributions. However, the location of the end-of-range is subject to uncertainties related to the accuracy of the relative proton stopping power estimates and thereby the water-equivalent path length (WEPL) along the beam. To remedy the range uncertainty, an in vivo measurement of the WEPL through the patient, i.e. a proton-range radiograph, is highly desirable. Towards that goal, we have explored a novel method of proton radiography based on the time-resolved dose measured by a flat panel imager (FPI). A 226 MeV pencil beam and a custom-designed range modulator wheel (MW) were used to create a time-varying broad beam. The proton imaging technique used exploits this time dependency by looking at the dose rate at the imager as a function of time. This dose rate function (DRF) has a unique time-varying dose pattern at each depth of penetration. A relatively slow rotation of the MW (0.2 revolutions per second) and a fast image acquisition (30 frames per second, ~33 ms sampling) provided a sufficient temporal resolution for each DRF. Along with the high output of the CsI:Tl scintillator, imaging with pixel binning (2  ×  2) generated high signal-to-noise data at a very low radiation dose (~0.1 cGy). Proton radiographs of a head phantom and a Gammex CT calibration phantom were taken with various configurations. The results of the phantom measurements show that the FPI can generate low noise and high spatial resolution proton radiographs. The WEPL values of the CT tissue surrogate inserts show that the measured relative stopping powers are accurate to ~2%. The panel did not show any noticeable radiation damage after the accumulative dose of approximately 3831 cGy. In summary, we have successfully demonstrated a highly practical method of generating proton radiography using an x-ray flat panel imager.

Background: Low back pain (LBP) has a prevalence of 84% in Africa. The commonest form of imaging is plain lumbar spine x-ray. It gives a radiation dose equivalent to 65 times a chest x-ray dose and sends one of the highest doses to the human reproductive organs. The commonest cause of LBP in Africa is degenerative disease. X-ray findings do not change mode of treatment yet most physicians still routinely request for x-rays., Methods: This is a systematic review of databases including The Cochrane, CINAHL plus, AMED, and MEDLINE. Key evidence was clinical guidelines on x-ray use for low back pain. Key search terms included low back pain, x-rays, guidelines, Ghana., Results: Four clinical guidelines on LBP emerged from two Systematic Reviews rated excellent and four good Randomized Controlled Trials: The European guidelines for acute and sub-acute non-specific Low Back Pain, The American College of Physicians and the American Pain Society guideline for diagnostic imaging for Low Back Pain, The NICE guidelines for persistent non-specific Low Back Pain and the Ghana Standard Treatment Guidelines (GSTG). All the guidelines agree that a good history and clinical examination for all LBP patients helps in diagnosing. Only GSTG recommends routine plain spinal x-rays., Conclusion: There is strong evidence indicating very little benefit from routine lumbar spine x-rays for all LBP. The GSTG needs to be revised considering the increased risks of radiation exposure and the x-ray costs., Funding: None declared., Competing Interests: Conflict of interest: None declared

Purpose: Edge illumination (EI) X-ray phase-contrast imaging (XPCI) has been under development at University College London in recent years, and has shown great potential for both laboratory and synchrotron applications. In this work, we propose a new acquisition and processing scheme. Contrary to existing retrieval methods for EI, which require as input two images acquired in different setup configurations, the proposed approach can retrieve an approximate map of the X-ray phase from a single image, thus significantly simplifying the acquisition procedure and reducing data collection times., Methods: The retrieval method is analytically derived, based on the assumption of a quasi-homogeneous object, i.e. an object featuring a constant ratio between refractive index and absorption coefficient. The noise properties of the input and retrieved images are also theoretically analyzed under the developed formalism. The method is applied to experimental synchrotron images of a biological object., Results: The experimental results show that the method can provide high-quality images, where the "edge" signal typical of XPCI images is transformed to an "area" contrast that enables an easier interpretation of the sample geometry. Moreover, the retrieved images confirm that the method is highly stable against noise., Conclusions: We anticipate that the developed approach will become the method of choice for a variety of applications of EI XPCI, thanks to its ability to simplify the acquisition procedure and reduce acquisitions time and dose to the sample. Future work will focus on the adaptation of the method to computed tomography and to polychromatic radiation from X-ray tubes., (Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)

In Nigeria, a large number of radiographic examinations are conducted yearly for various diagnostic purposes. However, most examinations carried out do not have records of doses received by the patients, and the employed exposure parameters used are not documented; therefore, adequate radiation dose management is hin-dered. The aim of the present study was to estimate the dose-area product (DAP) of patients examined in Nigeria, and to propose regional reference dose levels for nine common examinations (chest PA, abdomen AP, pelvis AP, lumbar AP, skull AP, leg AP, knee AP, hand AP, and thigh AP) undertaken in Nigeria. Measurement of entrance surface dose (ESD) was carried out using thermoluminescent dosimeter (TLD). Measured ESDS were converted into DAP using the beam area of patients in 12 purposely selected hospitals. Results of the study show that the maximum/ minimum ratio ranged from 3 for thigh AP to 57 in abdomen AP. The range of determined mean and 75th percentile DAPs were 0.18-17.16, and 0.25-28.59 Gy cm2, respectively. Data available for comparison show that 75th percentile DAPs in this study (in chest PA, abdomen AP, pelvis AP, lumbar AP) are higher than NRPB-HPE reference values. The DAP in this study is higher by factor of 31.4 (chest PA), 9.9 (abdomen AP), 2.2 (pelvis AP), and 2.1 (lumbar AP) than NRPB-HPE values. The relative higher dose found in this study shows nonoptimization of practice in Nigeria. It is expected that regular dose auditing and dose optimization implementation in Nigeria would lead to lower DAP value, especially in abdomen AP. The 75th percentile DAP distribution reported in this study could be taken as regional diagnostic reference level in the Southwestern Nigeria; however, a more extensive nationwide dose survey is required to establish national reference dose., (© 2016 The Authors.)

Some digital radiography (DR) detectors and software allow for remote download of exam statistics, including image reject status, body part, projection, and exposure index (EI). The ability to have automated data collection from multiple DR units is conducive to a quality control (QC) program monitoring institutional radiographic exposures. We have implemented such a QC program with the goal to identify outliers in machine radiation output and opportunities for improvement in radiation dose levels. We studied the QC records of four digital detectors in greater detail on a monthly basis for one year. Although individual patient entrance skin exposure varied, the radiation dose levels to the detectors were made to be consistent via phototimer recalibration. The exposure data stored on each digital detector were periodically downloaded in a spreadsheet format for analysis. EI median and stan-dard deviation were calculated for each protocol (by body part) and EI histograms were created for torso protocols. When histograms of EI values for different units were compared, we observed differences up to 400 in average EI (representing 60% difference in radiation levels to the detector) between units nominally cali-brated to the same EI. We identified distinct components of the EI distributions, which in some cases, had mean EI values 300 apart. Peaks were observed at the current calibrated EI, a previously calibrated EI, and an EI representing computed radiography (CR) techniques. Our findings in this ongoing project have allowed us to make useful interventions, from emphasizing the use of phototimers instead of institutional memory of manual techniques to improvements in our phototimer calibration. We believe that this QC program can be implemented at other sites and can reveal problems with radiation levels in the aggregate that are difficult to identify on a case-by-case basis., (© 2016 The Authors.)

Background: We wanted to assess the number of unnecessary radiographs done for acute knee injury patients and the accuracy of the Pittsburgh decision rules., Material and Methods: A retrospective observational study was done to look at the acute knee injury patients presented to a district general hospital Accident and Emergency Department from August 2011 till August 2013. We assessed the following parameters: sex, age, mechanism of injury, weight-bearing status and incidence of fractures in patients subjected to plain radiograph. A prospective study was then done from April 2014- August 2014 following implementation of the Pittsburgh decision rules., Results: 24% of the patients had knee X-ray, compared to 72.12% in the first cycle. 36.8% had fracture, compared to 6.1% first cycle, with 66.7 % reduction in x-rays. Pittsburgh decision rules sensitivity was 100% and specificity 85.3%, positive predictive value 45.8% and accuracy 87%., Conclusions: 1. The Pittsburgh decision rules is highly sensitive, specific and accurate in determining the need of X-ray in acute knee Injuries. 2. We found that the Pittsburgh decision rules performs well in our hospital, which coincides with previously published literature.

Purpose: The aim of this study is to compare the accuracy and reliability of spinal curvatures and vertebral rotation data based on patient-specific 3D models created by 3D imaging system or by bi-planar imaging coupled with Moiré-Fringe projections., Methods and Materials: Sixty-two consecutive patients from a single institution were prospectively included. For each patient, frontal and sagittal calibrated low-dose bi-planar X-rays were performed and coupled simultaneously with an optical Moiré back surface-based technology. The 3D reconstructions of spine and pelvis were performed independently by one radiologist and one technician in radiology using two different semi-automatic methods using 3D radio-imaging system (method 1) or bi-planar imaging coupled with Moiré projections (method 2). Both methods were compared using Bland-Altman analysis, and reliability using intraclass correlation coefficient (ICC)., Results: ICC showed good to very good agreement. Between the two techniques, the maximum 95 % prediction limits was -4.9° degrees for the measurements of spinal coronal curves and less than 5° for other parameters. Inter-rater reliability was excellent for all parameters across both methods, except for axial rotation with method 2 for which ICC was fair. Method 1 was faster for reconstruction time than method 2 for both readers (13.4 vs. 20.7 min and 10.6 vs. 13.9 min; p = 0.0001)., Conclusion: While a lower accuracy was observed for the evaluation of the axial rotation, bi-planar imaging coupled with Moiré-Fringe projections may be an accurate and reliable tool to perform 3D reconstructions of the spine and pelvis.

Setting: Chest radiographs (CXRs) are widely used for diagnosing pulmonary TB and assessing response to therapy. The Timika X-ray score has been proposed as a tool for measuring disease severity and predicting treatment outcome., Objective: To evaluate inter- and intra-reader agreement of Timika scores and assess the ability of the score to predict microbiologic outcome at 2 months., Design: Analytical validation study. Disease severity was measured by two readers using pretreatment radiographs and follow-up films taken at 2, 6 and 12 months after the start of treatment among 110 human immunodeficiency virus negative adults with pulmonary TB. One fourth of the films were reread to assess intra-reader agreement., Results: The two-component Timika score had high inter- and intra-reader agreement (intraclass correlation (ICC) inter = 75%, ICC intra > 0.81). Baseline Timika score was associated with positive month 2 smear (P = 0.0004) and culture status (P = 0.03). The average Timika score declined significantly over the course of successful treatment., Conclusion: The Timika score showed good inter- and intra-reader agreement and a significant association with microbiological outcomes after 2 months of treatment. The results of this study strengthen the evidence supporting the use of the Timika score for measuring disease severity on CXR.

Objective: The aim of this study was to evaluate the diagnostic value of x-ray dark-field imaging in projection radiography-based depiction of pneumothoraces in the neonatal murine lung, a potentially life-threatening medical condition that requires a timely and correct diagnosis., Materials and Methods: By the use of a unique preclinical model, 7-day-old C57Bl/6N mice received mechanical ventilation for 2 or 8 hours with oxygen-rich gas (FIO2 = 0.4; n = 24). Unventilated mice either spontaneously breathed oxygen-rich gas (FIO2 = 0.4) for 2 or 8 hours or room air (n = 22). At the end of the experiment, lungs were inflated with a standardized volume of air after a lethal dose of pentobarbital was administered to the pups. All lungs were imaged with a prototype grating-based small-animal scanner to acquire x-ray transmission and dark-field radiographs. Image contrast between the air-filled pleural space and lung tissue was quantified for both transmission and dark-field radiograms. After the independent expert's assessment, 2 blinded readers evaluated all dark-field and transmission images for the presence or absence of pneumothoraces. Contrast ratios, diagnostic accuracy, as well as reader's confidence and interreader agreement were recorded for both imaging modalities., Results: Evaluation of both x-ray transmission and dark-field radiographs by independent experts revealed the development of a total of 10 pneumothoraces in 8 mice. Here, the contrast ratio between the air-filled pleural space of the pneumothoraces and the lung tissue was significantly higher in the dark field (8.4 ± 3.5) when compared with the transmission images (5.1 ± 2.8; P < 0.05). Accordingly, the readers' diagnostic confidence for the diagnosis of pneumothoraces was significantly higher for dark-field compared with transmission images (P = 0.001). Interreader agreement improved from moderate for the analysis of transmission images alone (κ = 0.41) to very good when analyzing dark-field images alone (κ = 0.90) or in combination with transmission images (κ = 0.88). Diagnostic accuracy significantly improved for the analysis of dark-field images alone (P = 0.04) or in combination with transmission images (P = 0.02), compared with the analysis of transmission radiographs only., Conclusions: The significant improvement in contrast ratios between lung parenchyma and free air in the dark-field images allows the facilitated detection of pneumothoraces in the newborn mouse. These preclinical experiments indicate the potential of the technique for future clinical applications.

Sensitivity to sub-pixel sample features has been demonstrated as a valuable capability of phase contrast x-ray imaging. Here, we report on a method to obtain angular-resolved small angle x-ray scattering distributions with edge-illumination- based imaging utilizing incoherent illumination from an x-ray tube. Our approach provides both the three established image modalities (absorption, differential phase and scatter strength), plus a number of additional contrasts related to unresolved sample features. The complementarity of these contrasts is experimentally validated by using different materials in powder form. As a significant application example we show that the extended complementary contrasts could allow the diagnosis of pulmonary emphysema in a murine model. In support of this, we demonstrate that the properties of the retrieved scattering distributions are consistent with the expectation of increased feature sizes related to pulmonary emphysema. Combined with the simplicity of implementation of edge-illumination, these findings suggest a high potential for exploiting extended sub-pixel contrasts in the diagnosis of lung diseases and beyond.

Background: Accurate comprehension of the normal humeral morphology is crucial for anatomical reconstruction in shoulder arthroplasty. However, traditional morphological measurements for humerus were mainly based on cadaver and radiography. The purpose of this study was to provide a series of precise and repeatable parameters of the normal proximal humerus for arthroplasty, based on the three-dimensional (3-D) measurements., Methods: Radiographic and 3-D computed tomography (CT) measurements of the proximal humerus were performed in a sample of 120 consecutive adults. Sex differences, two image modalities differences, and correlations of the parameters were evaluated. Intra- and inter-observer reproducibility was evaluated using intraclass correlation coefficients (ICCs)., Results: In the male group, all parameters except the neck-shaft angle of humerus, based on 3-D CT images, were greater than those in the female group (P < 0.05). All variables were significantly different between two image modalities (P < 0.05). In 3-D CT measurement, all parameters expect neck-shaft angle had correlation with each other (P < 0.001), particularly between two diameters of the humeral head (r = 0.907). All parameters in the 3-D CT measurement had excellent reproducibility (ICC range, 0.878 to 0.936) that was higher than those in the radiographs (ICC range, 0.741 to 0.858)., Conclusions: The present study suggested that 3-D CT was more reproducible than plain radiography in the assessment of morphology of the normal proximal humerus. Therefore, this reproducible modality could be utilized in the preoperative planning. Our data could serve as an effective guideline for humeral component selection and improve the design of shoulder prosthesis.

Unlabelled: Spine fractures are diagnosed by X-ray or vertebral fracture assessment (VFA) by dual-energy X-ray absorptiometry (DXA) scanning. The use of VFA evaluation by DXA is still debated. We demonstrate that VFA is inferior relative to X-ray in visualizing vertebrae properly in the upper spine and therefore with a reduced diagnostic performance in detecting fractures., Introduction: Vertebral fracture assessment (VFA) by DXA has been evaluated for many years, and its use in clinical practice is still debated. In a cross-sectional setting, we aimed to compare VFA with traditional radiography in vertebral fracture (VF) diagnosis in severe osteoporotic patient., Methods: A total of 207 patients referred to the outpatient clinic for teriparatide treatment were screened, out of whom 35 (16.9 %) severe osteoporotic patients were identified (mean age 67.5 ± 11.3 years and median T-score -3.2 interquartile range (IQR) (-1.9 to -3.7). VF diagnosis was performed independently using VFA and X-ray in accordance with the semiquantitative (SQ) approach. The same technician performed the primary interpretation on both sets of images, after which a radiologist and an endocrinologist reviewed the evaluation for a conclusive judgement., Results: In total, 180 radiographic fractures were detected, corresponding to 5.1 fractures per individual. Using VFA, 18.5 % of vertebrae were considered unreadable, compared to 2.0 % on X-ray. The accuracy of VFA in VF detection using X-ray as a reference resulted in sensitivity and specificity of 75.5 and 86.7 %, respectively. Sensitivity decreased from the lumbar to thoracic level. Nevertheless, VFA only identified fractures consistently between Th11 and L3., Conclusion: Our data, based on a severe osteoporotic population, demonstrate that VFA is inferior relative to X-ray in visualizing vertebrae properly in the upper spine, resulting in vertebrae not being assessable for analysis and a reduced diagnostic performance in detecting fractures. Improvements in DXA techniques are needed for it to be comparable with X-ray in VF diagnosis.

The discovery of X-rays in 1895 by Wilhelm Conrad Röntgen transformed our understanding of both the physical world and our understanding of ourselves. Traditional anatomy as shown by Andreas Vesalius was learnt from dissection of the supine deceased body. Radiology showed anatomy in the living in a manner previously not possible, and has transformed our anatomical understanding, particularly of human growth and variation.

Purpose: High-spatial-resolution x-ray imaging in the few-ten-keV range is becoming increasingly important in several applications, such as small-animal imaging and phase-contrast imaging. The detector properties critically influence the quality of such imaging. Here the authors present a quantitative comparison of scintillator-based detectors for this energy range and at high spatial frequencies., Methods: The authors determine the modulation transfer function, noise power spectrum (NPS), and detective quantum efficiency for Gadox, needle CsI, and structured CsI scintillators of different thicknesses and at different photon energies. An extended analysis of the NPS allows for direct measurements of the scintillator effective absorption efficiency and effective light yield as well as providing an alternative method to assess the underlying factors behind the detector properties., Results: There is a substantial difference in performance between the scintillators depending on the imaging task but in general, the CsI based scintillators perform better than the Gadox scintillators. At low energies (16 keV), a thin needle CsI scintillator has the best performance at all frequencies. At higher energies (28-38 keV), the thicker needle CsI scintillators and the structured CsI scintillator all have very good performance. The needle CsI scintillators have higher absorption efficiencies but the structured CsI scintillator has higher resolution., Conclusions: The choice of scintillator is greatly dependent on the imaging task. The presented comparison and methodology will assist the imaging scientist in optimizing their high-resolution few-ten-keV imaging system for best performance.

Purpose: X-ray dark-field imaging promises information on the small angle scattering properties even of large samples. However, the dark-field image is correlated with the object's attenuation and phase-shift if a polychromatic x-ray spectrum is used. A method to remove part of these correlations is proposed., Methods: The experimental setup for image acquisition was modeled in a wave-field simulation to quantify the dark-field signals originating solely from a material's attenuation and phase-shift. A calibration matrix was simulated for ICRU46 breast tissue. Using the simulated data, a dark-field image of a human mastectomy sample was corrected for the finger print of attenuation- and phase-image., Results: Comparing the simulated, attenuation-based dark-field values to a phantom measurement, a good agreement was found. Applying the proposed method to mammographic dark-field data, a reduction of the dark-field background and anatomical noise was achieved. The contrast between microcalcifications and their surrounding background was increased., Conclusions: The authors show that the influence of and dispersion can be quantified by simulation and, thus, measured image data can be corrected. The simulation allows to determine the corresponding dark-field artifacts for a wide range of setup parameters, like tube-voltage and filtration. The application of the proposed method to mammographic dark-field data shows an increase in contrast compared to the original image, which might simplify a further image-based diagnosis.

Objectives: The radiological Pettersson score (PS) is widely applied for classification of arthropathy to evaluate costly haemophilia treatment. This study aims to assess and improve inter- and intra-observer reliability and agreement of the PS., Methods: Two series of X-rays (bilateral elbows, knees, and ankles) of 10 haemophilia patients (120 joints) with haemophilic arthropathy were scored by three observers according to the PS (maximum score 13/joint). Subsequently, (dis-)agreement in scoring was discussed until consensus. Example images were collected in an atlas. Thereafter, second series of 120 joints were scored using the atlas. One observer rescored the second series after three months. Reliability was assessed by intraclass correlation coefficients (ICC), agreement by limits of agreement (LoA)., Results: Median Pettersson score at joint level (PSjoint) of affected joints was 6 (interquartile range 3-9). Using the consensus atlas, inter-observer reliability of the PSjoint improved significantly from 0.94 (95 % confidence interval (CI) 0.91-0.96) to 0.97 (CI 0.96-0.98). LoA improved from ±1.7 to ±1.1 for the PSjoint. Therefore, true differences in arthropathy were differences in the PSjoint of >2 points. Intra-observer reliability of the PSjoint was 0.98 (CI 0.97-0.98), intra-observer LoA were ±0.9 points., Conclusions: Reliability and agreement of the PS improved by using a consensus atlas., Key Points: • Reliability of the Pettersson score significantly improved using the consensus atlas. • The presented consensus atlas improved the agreement among observers. • The consensus atlas could be recommended to obtain a reproducible Pettersson score.

In 2013, a nationwide investigation was conducted in Switzerland to establish the population's exposure from medical X rays. A hybrid approach was used combining the Raddose database accessible on-line by the participating practices and the Swiss medical tariffication system for hospitals. This study revealed that the average annual number of examinations is 1.2 per inhabitant, and the associated annual effective dose is 1.4 mSv. It also showed that computed tomography is the most irradiating modality and that it delivers 70 % of the total dose. The annual effective dose per inhabitant registered a 17 % increase in 5 y and is comparable with what was recently reported in neighbouring countries., (© The Author 2015. Published by Oxford University Press.)

The distance dependence of air kerma or dose rate of the primary radiation beam is not obvious for security scanners of cargo and people in which there is relative motion between a collimated source and the person or object being imaged. To study this problem, one fixed line source and three moving-source scan-geometry cases are considered, each characterized by radiation emanating perpendicular to an axis. The cases are 1) a stationary line source of radioactive material, e.g., contaminated solution in a pipe; 2) a moving, uncollimated point source of radiation that is shuttered or off when it is stationary; 3) a moving, collimated point source of radiation that is shuttered or off when it is stationary; and 4) a translating, narrow "pencil" beam emanating in a flying-spot, raster pattern. Each case is considered for short and long distances compared to the line source length or path traversed by a moving source. The short distance model pertains mostly to dose to objects being scanned and personnel associated with the screening operation. The long distance model pertains mostly to potential dose to bystanders. For radionuclide sources, the number of nuclear transitions that occur a) per unit length of a line source or b) during the traversal of a point source is a unifying concept. The "universal source strength" of air kerma rate at 1 m from the source can be used to describe x-ray machine or radionuclide sources. For many cargo and people scanners with highly collimated fan or pencil beams, dose varies as the inverse of the distance from the source in the near field and with the inverse square of the distance beyond a critical radius. Ignoring the inverse square dependence and using inverse distance dependence is conservative in the sense of tending to overestimate dose.

Background Context: X-ray absorption is highest in the organs and tissues located closest to the radiation source. The photon flux that crosses the body decreases from the entry surface toward the image receptor. The internal organs absorb x-rays and shield each other during irradiation. Therefore, changing the x-ray projection angle relative to the patient for specific spine procedures changes the radiation dose that each organ receives. Every organ has different radiation sensitivity, so irradiation from different sides of the body changes the biological influence and radiation risk potential on the total body, that is the effective dose (ED)., Purpose: The study aimed to determine the less radiation-sensitive sides of the body during lateral and anterior-posterior (AP) or posterior anterior (PA) directions., Study Design: The study used exposure of patient phantoms and Monte Carlo simulation of the effective doses., Patient Sample: Calculations for adults and 10-year-old children were included because the pediatric population has a greater lifetime radiation risk than adults., Outcome Measures: Pediatric and adult tissue and organ doses and ED from cervical, thoracic, and lumbar x-ray spine examinations were performed from different projections., Methods: Standard mathematical phantoms for adults and 10-year-old children, using PCXMC 2.0 software based on Monte Carlo simulations, were used to calculate pediatric and adult tissue and organ doses and ED. The study was not funded. The authors have no conflicts of interest to declare., Results: Spine x-ray exposure from various right (RT) LAT projection angles was associated with lower ED compared with the same left (LT) LAT projections (up to 28% and 27% less for children aged 10 and adults, respectively). The PA spine projections showed up to 64% lower ED for children aged 10 and 65% for adults than AP projections. The AP projection at the thoracic spine causes an excess breast dose of 543.3% and 597.0% for children aged 10 and adults, respectively., Conclusions: Radiation ED in spine procedures can be significantly reduced by performing x-ray exposures through the less radiation-sensitive sides of the body, which are PA in the frontal position and right lateral in the lateral position., (Copyright © 2015 Elsevier Inc. All rights reserved.)

The fusiform face area (FFA) has often been used as an example of a brain module that was developed through evolution to serve a specific purpose-face processing. Many believe, however, that FFA is responsible for holistic processing associated with any kind of expertise. The expertise view has been tested with various stimuli, with mixed results. One of the main stumbling blocks in the FFA controversy has been the fact that the stimuli used have been similar to faces. Here, we circumvent the problem by using radiological images, X-rays, which bear no resemblance to faces. We demonstrate that FFA can distinguish between X-rays and other stimuli by employing multivariate pattern analysis. The sensitivity to X-rays was significantly better in experienced radiologists than that in medical students with limited radiological experience. For the radiologists, it was also possible to use the patterns of FFA activations obtained on faces to differentiate X-ray stimuli from other stimuli. The overlap in the FFA activation is not based on visual similarity of faces and X-rays but rather on the processes necessary for expertise with both kinds of stimulus. Our results support the expertise view that FFA's main function is related to holistic processing., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Purpose: The purpose of this study was to develop a methodology to optimize computed radiographic techniques to image the skull, chest, and pelvis of a standard patient., Methods: Optimization was performed by varying exposure levels with different tube voltages to generate images of an anthropomorphic phantom. Image quality was evaluated using visual grading analysis and measuring objective parameters such as the effective detective quantum efficiency and the contrast-to-noise ratio. Objective and subjective evaluations were compared to obtain an optimized technique for each anatomic region., Results: Gold standard techniques provided a significant reduction in X-ray doses compared to the techniques used in our radiology service, without compromising diagnostic accuracy. They were chosen as follows 102 kVp/1.6 mAs for skull; 81 kVp/4.5 mAs for pelvis and 90 kVp/3.2 mAs for chest., Conclusion: There is a range of acceptable techniques that produce adequate images for diagnosis in computed radiography systems. This aspect allows the optimization process to be focused on the patient dose without compromising diagnostic capabilities. This process should be performed through association of quantitative and qualitative parameters, such as effective detective quantum efficiency, contrast-to-noise ratio, and visual grading analysis., (Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)

The purpose of this study is to investigate the feasibility of a novel indirect flat panel detector (FPD) system for removing scatter radiation. The substrate layer of our FPD system has a Pb net-like structure that matches the ineffective area and blocks the scatter radiation such that only primary X-rays reach the effective area on a thin-film transistor. To evaluate the performance of the proposed system, we used Monte Carlo simulations to derive the scatter fraction and contrast. The scatter fraction of the proposed system is lower than that of a parallel grid system, and the contrast is superior to that of a system without a grid. If the structure of the proposed FPD system is optimized with respect to the specifications of a specific detector, the purpose of the examination, and the energy range used, the FPD can be useful in diagnostic radiology., (Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)

Western medicine has long been dominated by a faith in the value of science and a belief in the power of technology. I study the history of how technology came to be seen as useful by focusing on one of the most dramatic new tools ever discovered: the X-ray machine. I use a statistically valid sampling of case records from 1900-1925 at the Pennsylvania Hospital to ask why and when physicians at these hospitals came to see X-rays as useful for patient care. Soon after the X-ray's 1895 invention there was seemingly worldwide agreement that it could be used to diagnose common conditions such as fractures and foreign bodies. However, it was only several decades later, after the underlying structure of the hospital changed due to importation of technologies from business, that X-ray images became seen as part of routine patient care., Competing Interests: Potential Conflicts of Interest: None Disclosed.

We present a method for simulating slot-scanning X-ray imaging using the general-purpose Monte Carlo simulation package PENELOPE and penEasy Imaging. Different phantoms can be defined with the PENGEOM package, which defines bodies as combinations of volumes limited by quadric surfaces. The source-detector geometry, the position of the object, the collimator, the X-ray tube properties, the detector material and the pixel dimensions are defined. The output of the time-delay integration detector is simulated using sequential slot outputs derived from penEasy Imaging. The simulations are validated using tungsten and aluminium test objects, which are both simulated and imaged. The simulations are compared to the X-ray images using standard image quality metrics. The MTF, NPS and DQE curves show that the real and simulated X-ray images are comparable in terms of spatial resolution, noise and frequency information. The implementation can be modified to suit alterations in the system being simulated., (Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)

The demand for greater accuracy of intensity-modulated radiotherapy (IMRT) has driven the development of more advanced verification systems for image-guided radiotherapy (IGRT). The purpose of this study is to investigate setup discrepancies measured between an orthogonal X-ray guidance system (XGS-10) and cone-beam computed tomography (CBCT) of Varian in the IMRT of patients with nasopharyngeal cancer (NPC). The setup errors measured by XGS-10 and CBCT at the treatment unit with respect to the planning CTs were recorded for 30 patients with NPC. The differences in residual setup errors between XGS-10 system and CBCT were computed and quantitatively analyzed. The time of image acquisition and image registration was recorded. The radiation doses delivered by CBCT and XGS-10 were measured using PTW0.6CC ionization chambers and a water phantom. The differences between setup errors measured by the XGS-10 system and CBCT were generally <1.5 mm for translations, indicating a reasonably good agreement between the two systems for patients with NPC in the translation directions of A-P (P = 0.856), L-R (P = 0.856) and S-I (P = 0.765). Moreover, compared with CBCT, XGS-10 took much shorter image acquisition and registration time (P <0.001) and delivered only a small fraction of extra radiation dose to the patients (P <0.001). These results indicate that XGS-10 offers high localization accuracy similar to CBCT and additional benefits including prompt imaging process, low imaging radiation exposure, real time monitoring, which therefore represents a potential attractive alternative to CBCT for clinical use., (Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)

Purpose: Cardiac x-ray detectors are used to acquire moving images in real-time for angiography and interventional procedures. Detective quantum efficiency (DQE) is not generally measured on these dynamic detectors; the required "for processing" image data and control of x-ray settings have not been accessible. By 2016, USA hospital physicists will have the ability to measure DQE and will likely utilize the International Electrotechnical Commission (IEC) standard for measuring DQE of dynamic x-ray imaging devices. The current IEC standard requires an image of a tilted tungsten edge test object to obtain modulation transfer function (MTF) for DQE calculation. It specifies the range of edge angles to use; however, it does not specify a preferred method to determine this angle for image analysis. The study aimed to answer the question "will my choice in method impact my results?" Four different established edge angle determination methods were compared to investigate the impact on DQE., Methods: Following the IEC standard, edge and flat field images were acquired on a cardiac flat-panel detector to calculate MTF and noise power spectrum, respectively, to determine DQE. Accuracy of the methods in determining the correct angle was ascertained using a simulated edge image with known angulations. Precision of the methods was ascertained using variability of MTF and DQE, calculated via bootstrapping., Results: Three methods provided near equal angles and the same MTF while the fourth, with an angular difference of 6%, had a MTF lower by 3% at 1.5 mm(-1) spatial frequency and 8% at 2.5 mm(-1); corresponding DQE differences were 6% at 1.5 mm(-1) and 17% at 2.5 mm(-1); differences were greater than standard deviations in the measurements., Conclusions: DQE measurements may vary by a significant amount, depending on the method used to determine the edge angle when following the IEC standard methodology for a cardiac x-ray detector. The most accurate and precise methods are recommended for absolute assessments and reproducible measurements, respectively.

Objective of this work is to evaluate radiation exposure from X-ray examinations in a large paediatric hospital in Serbia, including radiographic, fluoroscopic and computed tomography (CT) examinations in four age groups: 0-1, 1-5, 5-10 and 10-15 y. Incident air kerma was assessed for the following radiographies: chest (AP, PA, LAT), spine (AP, LAT), pelvis (AP), urinary tract (AP, PA) and skull (AP, PA, LAT). Kerma-area product was measured for the fluoroscopy examinations: barium swallow, barium meal, barium enema and micturating cystography. Dose in CT was assessed in terms of volume CT dose index and dose-length product for examinations of the head, chest and abdomen. The collected data were compared with other similar studies, which indicated a need to expand such survey to other paediatric hospitals in Serbia., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Purpose: To fabricate organic photovoltaic (OPV) cells with nanometric active layers sensitive to ionizing radiation and measure their dosimetric characteristics in clinical x-ray beams in the diagnostic tube potential range of 60-150 kVp., Methods: Experiments were designed to optimize the detector's x-ray response and find the best parameter combination by changing the active layer thickness and the area of the electrode. The OPV cell consisted of poly (3-hexylthiophene-2,5-diyl): [6,6]-phenyl C61 butyric acid methyl ester photoactive donor and acceptor semiconducting organic materials sandwiched between an aluminum electrode as an anode and an indium tin oxide electrode as a cathode. The authors measured the radiation-induced electric current at zero bias voltage in all fabricated OPV cells., Results: The net OPV current as a function of beam potential (kVp) was proportional to kVp(-0.5) when normalized to x-ray tube output, which varies with kVp. Of the tested configurations, the best combination of parameters was 270 nm active layer thicknesses with 0.7 cm(2) electrode area, which provided the highest signal per electrode area. For this cell, the measured current ranged from approximately 0.7 to 2.4 nA/cm(2) for 60-150 kVp, corresponding to about 0.09 nA-0.06 nA/mGy air kerma, respectively. When compared to commercial amorphous silicon thin film photovoltaic cells irradiated under the same conditions, this represents 2.5 times greater sensitivity. An additional 40% signal enhancement was observed when a 1 mm layer of plastic scintillator was attached to the cells' beam-facing side., Conclusions: Since both OPVs can be produced as flexible devices and they do not require external bias voltage, they open the possibility for use as thin film in vivo detectors for dose monitoring in diagnostic x-ray imaging.

Purpose: To develop an automated methodology to estimate patient examination dose in digital radiography (DR) imaging using DICOM metadata as a quality assurance (QA) tool., Methods: Patient examination and demographical information were gathered from metadata analysis of DICOM header data. The x-ray system radiation output (i.e., air KERMA) was characterized for all filter combinations used for patient examinations. Average patient thicknesses were measured for head, chest, abdomen, knees, and hands using volumetric images from CT. Backscatter factors (BSFs) were calculated from examination kVp. Patient entrance skin air KERMA (ESAK) was calculated by (1) looking up examination technique factors taken from DICOM header metadata (i.e., kVp and mA s) to derive an air KERMA (k air) value based on an x-ray characteristic radiation output curve; (2) scaling k air with a BSF value; and (3) correcting k air for patient thickness. Finally, patient entrance skin dose (ESD) was calculated by multiplying a mass-energy attenuation coefficient ratio by ESAK. Patient ESD calculations were computed for common DR examinations at our institution: dual view chest, anteroposterior (AP) abdomen, lateral (LAT) skull, dual view knee, and bone age (left hand only) examinations., Results: ESD was calculated for a total of 3794 patients; mean age was 11 ± 8 yr (range: 2 months to 55 yr). The mean ESD range was 0.19-0.42 mGy for dual view chest, 0.28-1.2 mGy for AP abdomen, 0.18-0.65 mGy for LAT view skull, 0.15-0.63 mGy for dual view knee, and 0.10-0.12 mGy for bone age (left hand) examinations., Conclusions: A methodology combining DICOM header metadata and basic x-ray tube characterization curves was demonstrated. In a regulatory era where patient dose reporting has become increasingly in demand, this methodology will allow a knowledgeable user the means to establish an automatable dose reporting program for DR and perform patient dose related QA testing for digital x-ray imaging.

The BioMedical Imaging and Therapy beamlines at the Canadian Light Source are used by many researchers to capture phase-based imaging data. These experiments have so far been limited by the small vertical beam size, requiring vertical scanning of biological samples in order to image their full vertical extent. Previous work has been carried out to develop a bent Laue beam-expanding monochromator for use at these beamlines. However, the first attempts exhibited significant distortion in the diffraction plane, increasing the beam divergence and eliminating the usefulness of the monochromator for phase-related imaging techniques. Recent work has been carried out to more carefully match the polychromatic and geometric focal lengths in a so-called `magic condition' that preserves the divergence of the beam and enables full-field phase-based imaging techniques. The new experimental parameters, namely asymmetry and Bragg angles, were evaluated by analysing knife-edge and in-line phase images to determine the effect on beam divergence in both vertical and horizontal directions, using the flat Bragg double-crystal monochromator at the beamline as a baseline. The results show that by using the magic condition, the difference between the two monochromator types is less than 10% in the diffraction plane. Phase fringes visible in test images of a biological sample demonstrate that this difference is small enough to enable in-line phase imaging, despite operating at a sub-optimal energy for the wafer and asymmetry angle that was used.