Establishing Cephalometric Norms in Primary Dentition Using Comprehensive Craniofacial Growth Analysis - A Digital Cephalometric Study

ABSTRACT Objective: To establish cephalometric norms in primary dentition among males and females using novel customized Comprehensive Cephalometric Growth (CCG) Analysis. Material and Methods: The study was conducted on 67 subjects with a mean age of 5.5 yrs. Digital lateral cephalometric radiographs were obtained using Planmeca Pro One. The digital images were then transferred to Nemoceph software. Craniofacial Growth (CCG) Analysis was configured in the software with five sub-groups. This sub-grouping was done such that related components were grouped together and comprehensively; it would provide an assessment of every component of the craniofacial region that could be affected either by treatment maneuver or growth process. The same was used for the cephalometric analysis and to determine the cephalometric norms in the primary dentition. Results: Certain linear measurements were higher among males when compared to females. However, most measurements remained similar among males and females during this age group. The CCG analysis provided a comprehensive knowledge of the craniofacial parameters during the growth process. Conclusion: The cephalometric norms during primary dentition thus established using Comprehensive Craniofacial Growth analysis would provide the data for early diagnosis and treatment planning in interceptive orthodontic treatment procedures.

Neonatal digital chest radiography- should we be using additional copper filtration?

OBJECTIVES: Copper filtration removes lower energy X-ray photons, which do not enhance image quality but would otherwise contribute to patient radiation dose. This study explores the use of additional copper filtration for neonatal mobile chest imaging. METHODS: A controlled factorial-designed experiment was used to determine the effect of independent variables on image quality and radiation dose. These variables included: copper filtration (0 Cu, 0.1 Cu and 0.2 Cu), exposure factors, source-to-image distance and image receptor position (direct / tray). Image quality was evaluated using absolute visual grading analysis (VGA) and contrast-to-noise ratio (CNR) and entrance surface dose (ESD) was derived using an ionising chamber within the central X-ray beam. RESULTS: VGA, CNR and ESD significantly reduced (p < 0.01) when using added copper filtration. For 0.1 Cu, the percentage reduction was much greater for ESD (60%) than for VGA (14%) and CNR (20%), respectively. When compared to the optimal combinations of parameters for incubator imaging using no copper filtration, an increase in kV and mAs when using 0.1-mm Cu resulted in better image quality at the same radiation dose (direct) or, equal image quality at reduced dose (in-tray). The use of 0.1-mm Cu for neonatal chest imaging with a corresponding increase in kV and mAs is therefore recommended. CONCLUSION: Using additional copper filtration significantly reduces radiation dose (at increased mAs) without a detrimental effect on image quality. ADVANCES IN KNOWLEDGE: This is the first study, using an anthropomorphic phantom, to explore the use of additional Cu for digital radiography neonatal chest imaging and therefore helps inform practice to standardise and optimise this imaging examination.

Evaluation of bone erosion in rheumatoid arthritis patients by high-resolution peripheral quantitative computed tomography scans: Comparison between two semi-automated programs in a three-dimensional setting.

AIM: The aim of this study was to compare OsiriX software with the previous published Medical Image Analysis Framework (MIAF) method to assess the volume of erosion in patients with rheumatoid arthritis (RA). METHODS: Forty RA patients underwent high-resolution peripheral quantitative computed tomography scans of the second and third metacarpophalangeal joints, and thirty-four patients with any bone erosion were enrolled. Two techniques were applied to erosion evaluation: (a) semi-automated MIAF software, and (b) semi-automated segmentation by free open-source Digital Imaging and Communications in Medicine viewer, OsiriX software. MIAF has been published before, but this is the first time that OsiriX has been used in this way in rheumatology. Bland & Altman plots described agreement between methods. RESULTS: Forty-eight erosions from 34 patients were analyzed. Mean age was 40.74 ± 5.32 years and mean disease duration was 10.68 ± 4.96 years. Both methods demonstrated a strong correlation regarding erosion volume (r = 0.96, P < 0.001). Median (interquartile range) of erosion volume was 12.14 (4.5-36.07) when MIAF was considered, and 11.80 (3.45-29.42) when the OsiriX tool was used (P = 0.139). MIAF and OsiriX showed good agreement when the Bland & Altman plot was performed. Evaluation by MIAF took 22.69 ± 6.71 minutes, whereas OsiriX took only 2.62 ± 1.09 minutes (P < 0.001). CONCLUSION: The three-dimensional segmentation of bone erosions can be done by both MIAF and OsiriX software with good agreement. However, because OsiriX is a widespread tool and faster, its method seems to be more feasible for evaluating peripheral bone damage, especially bone erosions.

Extended detail contrasts for TO.10 use on flat panel detector fluoroscopy systems.

OBJECTIVES: Leeds Test Object Ten (TO.10) is routinely used to subjectively estimate Threshold Contrast Detail Detectability (TCDD) as a measure of image quality in fluoroscopy. However, manufacturer guidance provides calibrated contrasts for only limited peak voltage and copper filtration thickness combinations. Prescribed testing conditions are often difficult to attain as modern flat panel fluoroscopic systems independently determine voltage and copper filtration thickness settings. This work aims to extend the range of TO.10 contrasts available for routine testing at peak voltage and copper thickness settings likely to be encountered. METHODS: Two methods are described for generalising the calculation of target contrasts: a three-dimensional interpolation/extrapolation model in MATLAB®, and a multivariate log-polynomial function. Both methods utilise the available calibrated contrasts to estimate contrasts at voltage and copper thickness combinations routinely encountered. RESULTS: Results are presented as Threshold Detection Index [Formula: see text] curves fit by a second-order polynomial of log [Formula: see text] to log [Formula: see text] . Results are found to be more accurate at unprescribed conditions while also reproducible for relatively consistent input air kerma rate (IAKR) expected from automatic dose rate controls (ADRC). CONCLUSIONS: The calculation of TO.10 contrasts at non-standard conditions aids in the determination of an absolute estimate of image quality in fluoroscopy with greater accuracy, reproducibility and efficiency. ADVANCES IN KNOWLEDGE: TO.10 detail contrasts for TCDD testing of fluoroscopy units have been significantly extended beyond those previously available. The described methods will aid the clinical physicist in absolute assessments of fluoroscopic image quality and facilitate inter system comparisons.

Dual-source abdominopelvic computed tomography: Comparison of image quality and radiation dose of 80 kVp and 80/150 kVp with tin filter.

OBJECTIVE: To compare the radiation dose and the objective and subjective image quality of 80 kVp and 80/150 kVp with tin filter (80/Sn150 kVp) computed tomography (CT) in oncology patients. METHODS: One-hundred-and-forty-five consecutive oncology patients who underwent third-generation dual-source dual-energy CT of the abdomen for evaluation of malignant visceral, peritoneal, extraperitoneal, and bone tumor were retrospectively recruited. Two radiologists independently reviewed each observation in 80 kVp CT and 80/Sn150 kVp CT. Modified line-density profile of the tumor and contrast-to-noise ratio (CNR) were measured. Diagnostic confidence, lesion conspicuity, and subjective image quality were calculated and compared between image sets. The effective dose and size-specific dose estimate (SSDE) were calculated in the image sets. RESULTS: Modified line-density profile analysis revealed higher attenuation differences between the tumor and normal tissue in 80 kVp CT than in 80/Sn150 kVp CT (127 vs. 107, P = 0.05). The 80 kVp CT showed increased CNR in the liver (8.0 vs. 7.6) and the aorta (18.9 vs. 16.3) than the 80/Sn150 kVp CT. The 80 kVp CT yielded higher enhancement of organs (4.9 ± 0.2 vs. 4.7 ± 0.4, P<0.001) and lesion conspicuity (4.9 ± 0.3 vs. 4.8 ± 0.5, P = 0.035) than the 80/Sn150 kVp CT; overall image quality and confidence index were comparable. The effective dose was reduced by 45.2% with 80 kVp CT (2.3 mSv ± 0.9) compared to 80/Sn150 kVp CT (4.1 mSv ± 1.5). The SSDE was 7.4 ± 3.8 mGy on 80/Sn150 kVp CT and 4.1 ± 2.2 mGy on 80 kVp CT. CONCLUSIONS: The 80 kVp CT reduced the radiation dose by 45.2% in oncology patients while showing comparable or superior image quality to that of 80/Sn150 kVp CT for abdominal tumor evaluation.

Clinically practiced and commercially viable nanobio engineered analytical methods for COVID-19 diagnosis.

The recent outbreak of the coronavirus disease (COVID-19) has left the world clueless. As the WHO declares this new contagion as a pandemic on the 11th of March 2020, the alarming rate of the spawn of the disease in such a short period has disarranged the globe. Standing against this situation researchers are strenuously searching for the key traits responsible for this pandemic. As knowledge regarding the dynamics and host-path interaction of COVID-19 causing Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is currently unknown, the formulation of strategies concerning antiviral treatment, vaccination, and epidemiological control stands crucial. Before designing adequate therapeutic strategies, it is extremely essential to diagnose the disease at the outset as early detection can have a greater impact on building health system capacity. Hence, a comprehensive review of strategies for COVID-19 diagnosis is essential in this existing global situation. In this review, sequentially, we have provided the clinical details along with genetic and proteomic biomarkers related to COVID-19. The article systematically enlightens a clear overview of the clinically adopted techniques for the detection of COVID-19 including oligonucleotide-based molecular detection, Point-of-Care immunodiagnostics, radiographical analysis/sensing system, and newly developed biosensing prototypes having commercial viability. The commercial kits/analytical methods based-sensing strategies have also been tabulated categorically. The critical insights on the developer, commercial brand name, detection methods, technical operational details, detection time, clinical specimen, status, the limit of detection/detection ability have been discussed comprehensively. We believe that this review may provide scientists, clinicians and healthcare manufacturers valuable information regarding the most recent developments/approaches towards COVID-19 diagnosis.

Comparing 10 kVp and 15% Rules in Extremity Radiography.

PURPOSE: To investigate the viability of the 10 kVp rule as a substitute for the 15% rule in obtaining extremity radiographs of high diagnostic quality while lowering patient radiation dose. The intention of this substitution is to allow technologists a simpler and quicker calculation for use in clinical settings to benefit patients without disrupting workflow. METHODS: Three anteroposterior or posteroanterior exposures were made on 3 anthropomorphic phantom extremities: hand, knee, and shoulder. Thermoluminescent dosimeters (TLDs) were placed at the center of each phantom; a new TLD was used for each exposure. Exposures were made on a Defininium 8000 digital radiography system (General Electric) using the unaltered, system-preset techniques used by the authors' imaging department, techniques adapted from the 10 kVp rule, and techniques adapted from the 15% rule. The detector exposure indicator from each image was used to compare image quality among the 3 exposures in each group. Entrance skin dose measured from the TLDs also were compared among the 3 exposures for each extremity. One TLD was used as a control to determine the amount of background radiation to which the TLDs were exposed. RESULTS: The detector exposure indicator remained in optimal range for every exposure with both applied rules as well as the system-preset techniques. Entrance skin dose was lower for both rules in the shoulder and hand trials, with the possibility of error during exposure and reading of the system-preset technique used on the knee phantom. Entrance skin dose also was lower for the shoulder and hand exposures when using the 10 kVp techniques compared with the 15% rule techniques. DISCUSSION: Aside from unknown entrance skin dose errors during knee imaging, no failures of the tested rules were found. Using manual technique selection rather than automatic exposure control allowed for consistent manipulation of technical factors. TLDs allowed for relatively reliable and quick readings from each exposure, although they could have been the cause of an error in the exposure reading of the preset technique of the knee. Environment and equipment were unchanged to maintain consistency. CONCLUSION: Results demonstrated that both the 15% rule and the 10 kVp rule successfully maintained or slightly improved image quality according to the detector exposure indicators. The results also demonstrated lowered patient dose according to the entrance skin doses. Based on these results, the 10 kVp rule might be a reasonable substitute for the 15% rule. Further research should be conducted with more repetitions that include digital radiography equipment for a wider range of examinations.

An evaluation of the effect of tube potential on clinical image quality using direct digital detectors for pelvis and lumbar spine radiographs.

INTRODUCTION: High kVp techniques, 15% or 10-kVp rules, are well-known dose reduction methods. Traditionally, the use of high tube potential (i.e. increased kVp) is associated with decreased radiographic contrast and overall image quality. Recent studies suggest contrast and image quality are not heavily reliant on kVp with digital systems. This study aims to assess the effects of the high tube potential technique on clinical radiographic image quality when using digital systems, to validate high kVp as a dose saving technique. METHODS: A selection of comparable pelvis and lumbar spine radiographs were collected from the hospital's picture archiving and communication system (PACS), with technical factors recorded. All clinical radiographs were assessed by 5 senior radiographers using a 15-point visual grading analysis (VGA) rubric. RESULTS: For 40 AP pelvis radiographs and 40 lateral lumbar spine radiographs, reduction in the dose area product (DAP) with higher kVp is seen. Average pelvis DAP at 75 kVp = 14.06 mGy.cm2 ; 85 kVp = 7.47 mGy.cm2 . Average lumbar spine DAP at 80 kVp = 15.76 mGy.cm2 ; 90 kVp = 14.83 mGy.cm2 . Image quality and contrast scores showed no statistically significant difference between the high and low kVp groups (z = 0.06 and 0.12, respectively). Average pelvis VGA score at 75 kVp = 11.26; 85 kVp = 12.55. Average lumbar spine VGA score at 80 kVp = 9.23; 90 kVp = 10.64. CONCLUSIONS: The high tube potential techniques allowed for reduced patient radiation doses whilst showing no degradation of diagnostic image quality in a clinical setting. This study successfully validates the high kVp technique as a useful tool for reducing patient radiation doses whilst maintaining high diagnostic image quality for digital pelvis and lumbar spine radiography.

Determination of radiation dose and low-dose protocol for digital chest tomosynthesis using radiophotoluminescent (RPL) glass dosimeters.

PURPOSE: This study aimed to determine a low-dose protocol for digital chest tomosynthesis (DTS). METHODS: Five simulated nodules with a CT number of approximately 100 HU with size diameter of 3, 5, 8, 10, and 12 mm were inserted into an anthropomorphic chest phantom (N1 Lungman model), and then scanned by DTS system (Definium 8000) with varying tube voltage, copper filter thickness, and dose ratio. Three radiophotoluminescent (RPL) glass dosimeters, type GD-352 M with a dimension of 1.5 × 12 mm, were used to measure the entrance surface air kerma (ESAK) in each protocol. The effective dose (ED) was calculated using the recorded total dose-area-product (DAP). The signal-to-noise ratio (SNR) was determined for qualitative image quality evaluation. The image criteria and nodule detection capability were scored by two experienced radiologists. The selected low-dose protocol was further applied in a clinical study with 30 pulmonary nodule follow-up patients. RESULTS: The average ESAK obtained from the standard default protocol was 1.68 ± 0.15 mGy, while an ESAK of 0.47 ± 0.02 mGy was found for a low-dose protocol. The EDs for the default and low-dose protocols were 313.98 ± 0.72 µSv and 100.55 ± 0.28 µSv, respectively. There were small non-significant differences in the image criteria and nodule detection scoring between the low-dose and default protocols interpreted by two radiologists. The effective dose of 98.87 ± 0.08 µSv was obtained in clinical study after applying the low-dose protocol. CONCLUSIONS: The low-dose protocol obtained in this study can substantially reduce radiation dose while preserving an acceptable image quality compared to the standard protocol.

Improving radiographic imaging for circular frames: the Cambridge experience.

INTRODUCTION: Limb reconstruction using circular frames requires complex accurate measurements to achieve correction of mechanical bone axis. Inadequate imaging could ultimately lead to poor clinical outcome. Therefore, radiographs should be obtained in a standardised manner to yield accurate results. Our aim is to improve the effectiveness of post-operative imaging by obtaining precise examinations and improving the accuracy of frame correction; therefore, reducing technical repeats, radiation exposure, time waste in clinic, and achieving cost effectiveness. METHODS: We implemented a simple technique for obtaining adequate imaging using standard X-ray equipment. This technique was introduced to the radiographers in the radiology department to image patients with circular frames. Images were taken by obtaining a field of view using the X-ray machine cone of light that is orthogonal to the location of interest in both the antero-posterior (AP) and lateral planes. We compared the quality of radiographs, number of repeated X-rays and radiation dose both before and after implementing our protocol RESULTS: We assessed 54 consultations before and 63 consultations after the implementation of our protocol. The results showed a reduction in inadequate radiographs from 78% to 13% department at Addenbrooke's Hospital at a statistical significance of p < 0.00001. In addition, we found a potential radiation dose reduction of 2.7-0.32mSev between the two cohorts. Our results indicate that there would also be a reduction in the cost to the department as well as time spent repeating inaccurate radiographs. CONCLUSION: We have been able to achieve a significant improvement in the quality of post-operative radiographic imaging and have expanded its use to adult frame patients with a background of traumatic or infectious aetiologies.

Evaluation of three-dimensional iterative image reconstruction in virtual monochromatic imaging at 40 kilo-electron volts: phantom and clinical studies to assess the image noise and image quality in comparison with other reconstruction techniques.

OBJECTIVE: The purpose of this study was to evaluate the image quality in virtual monochromatic imaging (VMI) at 40 kilo-electron volts (keV) with three-dimensional iterative image reconstruction (3D-IIR). METHODS: A phantom study and clinical study (31 patients) were performed with dual-energy CT (DECT). VMI at 40 keV was obtained and the images were reconstructed using filtered back projection (FBP), 50% adaptive statistical iterative reconstruction (ASiR), and 3D-IIR. We conducted subjective and objective evaluations of the image quality with each reconstruction technique. RESULTS: The image contrast-to-noise ratio and image noise in both the clinical and phantom studies were significantly better with 3D-IIR than with 50% ASiR, and with 50% ASiR than with FBP (all, p < 0.05). The standard deviation and noise power spectra of the reconstructed images decreased in the order of 3D-IIR to 50% ASiR to FBP, while the modulation transfer function was maintained across the three reconstruction techniques. In most subjective evaluations in the clinical study, the image quality was significantly better with 3D-IIR than with 50% ASiR, and with 50% ASiR than with FBP (all, p < 0.001). Regarding the diagnostic acceptability, all images using 3D-IIR were evaluated as being fully or probably acceptable. CONCLUSIONS: The quality of VMI at 40 keV is improved by 3D-IIR, which allows the image noise to be reduced and structural details to be maintained. ADVANCES IN KNOWLEDGE: The improvement of the image quality of VMI at 40 keV by 3D-IIR may increase the subjective acceptance in the clinical setting.

The effect of a new universal laser aiming device in C-arm fluoroscopy on the technician's accuracy.

OBJECTIVES: This study aims to introduce a new low-cost universal laser aiming device (LAD) that can be used in existing C-arm fluoroscopy devices, independent of brand and model, and to determine whether this new universal LAD improves technician accuracy in locating the desired region at the midpoint of the fluoroscopic image. MATERIALS AND METHODS: A low-priced universal LAD that is compatible with existing 12-inch C-arm fluoroscopy devices was designed. Eight radiology technicians with varied levels of experience in C-arm fluoroscopy participated in the study. A 12 mm cortical screw with a diameter of 3.5 mm was placed on proximal, diaphyseal, and distal points of femur, tibia, and humerus bones in the anteroposterior plane on L3 vertebrae and the left pubis arm in the pelvis bone model. Technicians were asked to align each screw in the image center 10 times from a distance of 30 cm in the anterolateral plane, first without the LAD and then with the LAD. The distance of the screw head to the center point was measured from the 3,520 images with the help of medical viewer software based on the X- and Y-axis. RESULTS: Each fluoroscopic image was divided into 48 equal parts and the length of a part was taken as one unit for distance measurements. The compliance between technicians without the LAD was 0.347 (95% confidence interval [CI]: 0.208-0.47, p=0.001) and with the LAD was 0.687 (95% CI: 0.621-0.741, p=0.001). The distance between the screw head and the center of the image without the LAD was 19.0±9.8 for technicians with more than 10 years of experience and 28.0±12.9 for those with less than 10 years of experience. This difference was statistically significant (p=0.001). When the LAD was used, the difference between the less experienced (3.1±1.5) and more experienced (3.3±2.0) technicians was statistically reduced, along with the distance (p=0.033). CONCLUSION: The use of the LAD with C-arm fluoroscopy appears to be successful in helping technicians capture the desired point in the center of the fluoroscopic image. The use of the LAD reduces the experience gap between technicians.

Removal of Antiscatter Grids for Spinal Digital Subtraction Angiography: Dose Reduction without Loss of Diagnostic Value.

Background Spinal digital subtraction angiography (DSA) exposes patients and operators to substantial amounts of radiation. Antiscatter grid (ASG) removal is used to decrease radiation exposure but may reduce image quality. Purpose To determine whether ASG removal during spinal DSA in adults reduces radiation dose while maintaining diagnostic image quality and whether dose reduction is related to body mass index (BMI). Materials and Methods This Health Insurance Portability and Accountability Act-compliant prospective study included adults undergoing spinal DSA between January and December 2016. Each procedure included an additional angiographic acquisition performed twice, once with and once without ASG, either documenting the artery of Adamkiewicz (no pathology group) or the condition leading to the procedure (pathology group). Dose differences between study acquisitions and the influence of BMI were evaluated via paired t test. Two neurointerventionalists blinded to acquisition protocols were asked to independently evaluate a sample of 40 study acquisitions (20 with ASG, 20 without ASG) from 20 randomly selected participants to (a) rate image quality, (b) categorize findings, and (c) determine whether images had been obtained with or without ASG. Percentage agreement on image quality, findings categorization, and ability to correctly identify the acquisition protocol was calculated for both readers. Results Fifty-three participants (mean age ± standard deviation, 51 years ± 15.2; 32 men) were evaluated. ASG removal reduced the mean dose per acquisition by approximately 33% (mean dose-area product and air kerma decreased from 202 to 135.6 µGy/m2 and from 35.3 to 24 mGy, respectively; P < .001) independently of BMI (P = .3). Both readers evaluated all images (40 of 40) as being of diagnostic quality and correctly categorized findings in 19 of 20 (95%) cases. Overall percentage agreement for correct protocol identification was 60% (12 of 20) for grid-in and 45% (nine of 20) for grid-out images. Conclusion Antiscatter grid removal during spinal digital subtraction angiography decreased participants' radiation exposure while preserving diagnostic image quality. © RSNA, 2020.

Chest CT in patients after lung transplantation: A retrospective analysis to evaluate impact on image quality and radiation dose using spectral filtration tin-filtered imaging.

OBJECTIVES: The purpose of this study was to investigate the impact of a 150kV spectral filtration chest imaging protocol (Sn150kVp) combined with advanced modeled iterative reconstruction (ADMIRE) on radiation dose and image quality in patients after lung-transplantation. METHODS: This study included 102 patients who had unenhanced chest-CT examinations available on both, a second-generation dual-source CT (DSCT) using standard protocol (100kVp, filtered-back-projection) and, on a third-generation DSCT using Sn150kVp protocol with ADMIRE. Signal-to-noise-ratio (SNR) was measured in 6 standardized regions. A 5-point Likert scale was used to evaluate subjective image quality. Radiation metrics were compared. RESULTS: The mean time interval between the two acquisitions was 1.1±0.7 years. Mean-volume-CT-dose-index, dose-length-product and effective dose were significantly lower for Sn150kVp protocol (2.1±0.5mGy;72.6±16.9mGy*cm;1.3±0.3mSv) compared to 100kVp protocol (6.2±1.8mGy;203.6±55.6mGy*cm;3.7±1.0mSv) (p<0.001), equaling a 65% dose reduction. All studies were considered of diagnostic quality. SNR measured in lung tissue, air inside trachea, vertebral body and air outside the body was significantly higher in 100kVp protocol compared to Sn150kVp protocol (12.5±2.7vs.9.6±1.5;17.4±3.6vs.11.8±1.8;0.7±0.3vs.0.4±0.2;25.2±6.9vs.14.9±3.3;p<0.001). SNR measured in muscle tissue was significantly higher in Sn150kVp protocol (3.2±0.9vs.2.6±1.0;p<0.001). For SNR measured in descending aorta there was a trend towards higher values for Sn150kVp protocol (2.8±0.6 vs. 2.7±0.9;p = 0.3). Overall SNR was significantly higher in 100kVp protocol (5.0±4.0vs.4.0±4.0;p<0.001). On subjective analysis both protocols achieved a median Likert rating of 1 (25th-75th-percentile:1-1;p = 0.122). Interobserver agreement was good (intraclass correlation coefficient = 0.73). CONCLUSIONS: Combined use of 150kVp tin-filtered chest CT protocol with ADMIRE allows for significant dose reduction while maintaining highly diagnostic image quality in the follow up after lung transplantation when compared to a standard chest CT protocol using filtered back projection.

Simulation of three intraoral radiographic techniques in pediatric dental patients: subjective comfort assessment using the VAS and Wong-Baker FACES Pain Raiting Scale.

BACKGROUND: Perception of pain associated with intraoral radiography in pediatric patients was evaluated through statistical comparisons of data obtained using the Wong-Baker FACES Pain Raiting Scale (WBFPRS) and visual analog scale (VAS) scoring. METHODS: A total of 75 pediatric patients aged 6-12 years were included in this study. Simulations of each of three radiological methods (analog films, CCD sensor and phosphorus plates) were performed on 25 pediatric patients. Following the simulations, the meaning of each facial expression on the WBFPRS and the numbers on the VAS were explained to each child. For the comparison between groups, the homogeneity of the variances was tested with Levene's test; because the variances were not homogeneous, Welch's test was used. Tamhane's T2 test was used because the homogeneity assumption was not provided to determine the source of the difference between the groups. RESULTS: When the conventional method was compared to the PSPL (photostimulable phosphor luminescence) method, no significant differences were noted in either the WBFPRS or VAS results (p >0.05). The results obtained from both of the scales were significantly different between the conventional method and the CCD sensor method (p < 0.05). When the PSPL and CCD sensors were compared, a significant difference was observed for the WBFPRS (p < 0.05). It was found the highest level of pain scores when used the CCD sensor method than the analog film and PSPL methods (p < 0.05). CONCLUSIONS: It is expected that digital radiographic techniques will be improved in the future and that their disadvantages will be eliminated, resulting in imaging devices that are more comfortable for pediatric patients.

Investigation of detector uniformity issues for Siemens Inspiration systems.

PURPOSE: Detector uniformity is an important parameter in digital mammography to guarantee a level of image quality adequate for early detection of breast cancer. Many problems with digital systems have been determined through the uniformity measurement, primarily as a result of incorrect flat-field calibration and artifacts caused by image receptor defects. The European guidelines suggest a method for the image uniformity assessment based on measurement of Signal-to-Noise ratio (SNR) and Pixel Value (PV) across a uniform image. Nineteen mammography systems from the same manufacturer installed in our organization incorporate an a-Se direct conversion detector. Since their installation, instability and inconsistency of image uniformity has attracted medical physicist attention. A number of different tests have been carried out in order to understand and establish reasons for this instability. METHODS: Three different tests have been performed to evaluate the impact of the heel effect, detector temperature and ghosting on the uniformity images. All the tests are based on the acquisition of uniform images as suggested by the European Guidelines for Quality Assurance in Breast Cancer Screening and Diagnosis. RESULTS: Results show that an increase in detector temperature produces an increase of SNR and decrease of uniformity. A further decrease of uniformity ranging between 20% and 30% is due to the ghosting while a decrease of about 10% is due the heel effect. CONCLUSIONS: X-ray tube, system geometry and detector have an impact on the system uniformity and an understanding of the contribution of each is necessary in order to obtain comparable image quality among all the systems.

Lodox®: the invaluable radiographic solution in the forensic setting.

The benefits of a comparatively inexpensive radiographic system such as the Lodox® scanner in forensic facilities where CT-imaging and radiologist support is not financially viable will be explored. Prodigious caseloads in many under-resourced mortuaries preclude the use of advanced radiological modalities. The aim of this research is to examine the utilization of the Lodox® scanner in one of the busiest mortuaries in South Africa in relation to the nature of the cases scanned and, furthermore, to provide case studies where this imaging modality proved vital in the examination of the deceased and in the approach to the autopsy. The research is a retrospective epidemiological review on the use of the Lodox® scanner at the Salt River Medico-legal Laboratory, Cape Town, South Africa, from 1 January 2017 to 31 December 2017. A total of 3885 cases was admitted to the mortuary; the majority was scanned. A large proportion of cases were male. Ages ranged from foetuses to the elderly. The manner of death in more than a third of the cases was homicide which mainly involved firearm fatalities. This was followed by natural deaths. Pertinent case studies are presented to demonstrate that the use of the Lodox® scanner as an adjunct (or even obviating autopsy) proves to save time and labour and is financially beneficial. In conclusion, the Lodox® scanner is an indispensable tool in mortuaries with heavy caseloads because its use improves quality assurance, saves time, and is cost effective in the examination of both natural and unnatural deaths.

Modern Image Acquisition System Reduces Radiation Exposure to Patients and Staff During Complex Endovascular Aortic Repair.

OBJECTIVE: Radiation damage during complex endovascular aortic repair (EVAR) is of major concern to patients and medical staff. This study investigates primarily the influence of different acquisition systems (Allura ClarityIQ vs. Allura Xper, Philips Healthcare, Best, the Netherlands) on radiation dose. Secondly, radiation exposure was analysed for operator positions as well as for procedure and patient specific parameters. METHODS: This was a retrospective study of prospectively collected data. The study prospectively included 62 consecutive patients (mean age 71.2 ± 8.4 years; 63% males) who underwent complex EVAR including fenestrated or branched EVAR of the thoraco-abdominal or the aortic arch from 30 June 2015 to 20 May 2016. In half the patients an advanced dose and real time image noise reduction technology (Allura ClarityIQ) was used, and in the other half the reference acquisition system (Allura Xper) was used. Patient demographics included age, gender, and body mass index. RESULTS: Sixty-two patients with mean age of 71.2 ± 8.4 years (63% males; 39/62) were treated using either Allura ClarityIQ or Allura Xper. Patients treated using Allura ClarityIQ had lower cumulative dose area product (18,948.3 ± 14,648.5 cGy cm2vs. 38,512.4 ± 24,105.4 cGy cm2, p < 0.001) and air kerma (2237.9 ± 1808 mGy vs. 4031 ± 3260.2 mGy, p = .010) in comparison with patients treated using Allura Xper. CONCLUSION: Advanced dose and real time image noise reduction technology, such as Allura ClarityIQ, is a useful tool to lower the amount of radiation for patient and staff during complex endovascular aortic procedures.

Overcoming the challenges of high-energy X-ray ptychography.

X-ray ptychography is a coherent diffraction imaging technique with a high resolving power and excellent quantitative capabilities. Although very popular in synchrotron facilities nowadays, its implementation with X-ray energies above 15 keV is very rare due to the challenges imposed by the high energies. Here, the implementation of high-energy X-ray ptychography at 17 and 33.6 keV is demonstrated and solutions to overcome the important challenges are provided. Among the particular aspects addressed are the use of an efficient high-energy detector, a long synchrotron beamline for the high degree of spatial coherence, a beam with 1% monochromaticity providing high flux, and efficient multilayer coated Kirkpatrick-Baez X-ray optics to shape the beam. The constraints imposed by the large energy bandwidth are carefully analyzed, as well as the requirements to sample correctly the high-energy diffraction patterns with small speckle size. In this context, optimized scanning trajectories allow the total acquisition time to be reduced by up to 35%. The paper explores these innovative solutions at the ID16A nano-imaging beamline by ptychographic imaging of a 200 nm-thick gold lithography sample.

Enhanced radiation exposure associated with anterior-posterior x-ray tube position in young women undergoing cardiac computed tomography.

Given the current increase in the incidence of coronary artery disease in younger women as well as the high lifetime risk of developing an x-ray-induced malignancy in this population, we aimed at assessing chest radiation in 206 women ≤55 years old undergoing coronary calcium scoring (CACS) by using a Monte Carlo simulation tool. Our data indicate that the simulated radiation dose of the female breast during CACS depends substantially on the starting position of the x-ray tube, with an almost 2 times excess of breast radiation exposure being measured during anterior-posterior tube positioning. Thus, an additional technical feature taking into account the position of the x-ray tube when acquisition is triggered might be an important tool to reduce radiation exposure of the female breast during CACS.