Search

PURPOSE: To determine the relationship between pulmonary function, aerobic exercise capacity and physical activity participation in adults following burn. METHODS: Eight burn injured males aged 20-55 years (%TBSA 33.3±18.7, 5.1 years±1.8 post injury), and 30 healthy adult controls participated. Pulmonary function was assessed during rest via spirometry. A graded exercise test measuring peak oxygen consumption (VO(2peak)) and oxygen saturation (S(p)O(2)) was conducted, and physical activity was assessed via the Older Adult Exercise Status Inventory (OA-EI). RESULTS: No significant correlation was observed between resting pulmonary function, aerobic capacity and physical activity participation for burn injured patients or controls. Two burn injured patients presented with obstructive ventilatory defects, and one displayed a restrictive ventilatory defect. Burn injured patients had a significantly lower VO(2peak) (p<0.001) and time to fatigue (p=0.026), and a greater degree of oxygen desaturation (p=0.063, Effect Size=1.02) during a graded exercise test. Burn injured patients reported significantly less participation in leisure-related activity>9 METs (p=0.01), and significantly greater participation in work-related activity (p=0.038), than healthy controls. CONCLUSION: Compromised lung function, decreased aerobic capacity and reduced participation in leisure-related physical activity may still exist in some adults, even up to 5 years post injury. Limitations and long term outcomes of cardiopulmonary function and physical fitness need to be considered in the prescription of exercise rehabilitation programmes following burn. [ABSTRACT FROM AUTHOR]

As we become increasingly dependent on our picture archiving and communications system (PACS) for the clinical practice of medicine, the demand for improved reliability becomes urgent. Borrowing principles from the discipline of Reliability Engineering, we have identified components of our system that constitute single points of failure and have endeavored to eliminate these through redundant components and manual work-around procedures. To assess the adequacy of our preparations, we have identified a set of plausible events that could interfere with the function of one or more of our PACS components. These events could be as simple as the loss of the network connection to a single component or as broad as the loss of our central data center. We have identified the need to continue to operate during adverse conditions, as well as the requirement to recover rapidly from major disruptions in service. This assessment led us to modify the physical locations of central PACS components within our physical plant. We are also taking advantage of actual disruptive events coincident with a major expansion of our facility to test our recovery procedures. Based on our recognition of the vital nature of our electronic images for patient care, we are now recording electronic images in two copies on disparate media. The image database is critical to both continued operations and recovery. Restoration of the database from periodic tape backups with a 24-hour cycle time may not support our clinical scenario: acquisition modalities have a limited local storage capacity, some of which will not contain the daily workload. Restoration of the database from the archived media is an exceedingly slow process, that will likely not meet our requirement to restore clinical operations without significant delay. Our PACS vendor is working on concurrent image databases that would be capable of nearly immediate switchover and recovery. Copyright © 2001 by W.B. Saunders Company [ABSTRACT FROM AUTHOR]

This article presents a review of image quality assessment methods for monochrome CRTs in the field as opposed to the laboratory. The review includes image quality programs at the University of Washington, the University of Texas at Houston, the University of Michigan, and the University of Arizona. CRT manufacturers and display-board suppliers also are concerned with image quality, particularly with respect to the life time of the CRT. The programs show that the need for image quality assessment for CRTs in the clinic is recognized. Although several experimental programs are in place, there is no universally accepted program. In fact, the clinical consequences of degraded monitor performance are not even well known and must be established. The existing programs mainly are based on the most comprehensive test pattern, the SMPTE pattern. The programs permit assessment of maximum luminance, display function, dynamic range, and contrast. They do not permit assessment of spatial resolution. There is no easy method to determine the spatial resolution in the field as precisely as desired simply because there are no visual aids (test patterns) to reliably determine loss of spatial resolution and signal-to-noise ratio using human observers. This report also presents initial and encouraging data obtained at the University of Arizona with a CCD camera. This CCD camera has the potential to be developed into an important tool for practical CRT evaluation for the clinic. Copyright (c) 1999 by W.B. Saunders Company [ABSTRACT FROM AUTHOR]

Insufficient milk syndrome is defined as failure to thrive in infants due to insufficient daily breastmilk intake. This discussion examines a possible association between insufficient milk syndrome and maternal postpartum hemorrhage. Ten consecutive cases of insufficient milk syndrome associated with maternal postpartum hemorrhage were identified. The mothers presented between 3 and 35 days postpartum. Maternal postpartum blood loss ranged from 500-1500 ml in eight cases (mean: 963 ml); in two cases, blood loss was noted as 400++ and 200++, respectively. Six mothers experienced a drop of hemoglobin by >30g/L; two had a drop in blood pressure >30mmHg for >20 minutes. All infants were failing to thrive. Five infants suffered hypernatremic dehydration with serum sodium levels ranging from 148-166mmolL. Breastmilk electrolytes were measured in six cases, and elevated sodium levels, ranging from 21-lOOmmol/L, in five cases. These data serve to heighten awareness of insufficient milk syndrome as a potential consequence of postpartum hemorrhage. Early postpartum review of all breastfeeding mothers and infants is strongly encouraged. [ABSTRACT FROM AUTHOR]

Background: Spear®-T sold as a contact foliar spray for the control of glasshouse pests such as aphids, thrips, spider mites and whiteflies, contains the recombinant spider venom peptide GS-ω/κ-HxTx-Hv1h (named as GS-ω/κ-HxTx-Hv1a by Vestaron) as the active ingredient. Here we investigate whether fusion of the peptide to snowdrop lectin, (Galanthus nivalis agglutinin; GNA) enhances the efficacy of this venom peptide towards aphid pests., Results: Recombinant GS-ω/κ-HxTx-Hv1h (HxTx-Hv1h) and an HxTx-Hv1h/GNA fusion protein were produced using the yeast Pichia pastoris. Purified proteins showed comparable toxicity when injected into lepidopteran (Mamestra brassicae) larvae, but significant differences in oral and contact activity towards aphids. HxTx-Hv1h had comparable acute oral toxicity to pea (Acyrthosiphon pisum) and peach potato (Myzus persicae) aphids with respective Day (2) median lethal concentration (LC 50 ) values of 111 and 108 μm derived from diet assays. The fusion protein also showed comparable oral toxicity to both species but D2 LC 50 values were >3-fold lower (35 and 33 μm for pea and peach potato aphids, respectively) as compared to HxTx-Hv1h. Topically applied toxin and fusion protein, but not GNA, caused significant reductions in pea aphid survival. Contact effects on mortality were significantly greater for aphids exposed to fusion protein as compared to toxin alone. Whole aphid fluorescence microscopy and immunoblotting suggest that improved efficacy is due to enhanced persistence of HxTx-Hv1h when fused to GNA following internalisation of ingested or topically applied proteins., Conclusions: This is the first study to report on the insecticidal activity of HxTx-Hv1h towards aphids and results suggest that a fusion protein-based approach offers opportunities to significantly enhance oral and contact efficacy of naturally derived toxins, such as HxTx-Hv1h, towards crop pests. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., (© 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

Background: Family-based lifestyle interventions (FBLIs) are an important method for treating childhood weight problems. Despite being recognized as an effective intervention method, the optimal structure of these interventions for children's overweight and obesity has yet to be determined. Our aim was to better understand participants' (a) implementation of behaviour strategies and long-term outcomes, (b) perceptions regarding the optimal structure of FBLIs, and (c) insights into psychological concepts that may explain the success of these programs., Methods: Purposive sampling was used to recruit participants. We conducted focus groups as well as one-to-one interviews with parents (n = 53) and children (n = 50; aged 7-13, M = 9.4 yr, SD = 3.1) three months following their involvement in a 10-week, multi-component, FBLI involving education and activities relating to healthy nutrition, physical activity, and behavior modification. Using an interpretivist approach, a qualitative study design was employed to examine participant experiences., Results: We identified three higher-order categories: (a) participants' program experiences and perceptions (b) lifestyle changes post-program, and (c) recommendations for optimizing family-based programs. Themes identified within these categories included (a) support and structure & content, (b) diet and physical activity, and (c) in-program recommendations and post-program recommendations., Conclusions: We identified several challenges that can impair lasting behavior change (e.g., physical activity participation) following involvement in a FBLI. On optimizing these programs, participants emphasized fun, interactive content, interpersonal support, appropriate educational content, and behavior change techniques. Concepts rooted in motivational theory could help address calls for greater theoretical and mechanistic insight in FBLIs. Findings may support research advancement and assist health professionals to more consistently realize the potential of these interventions., (© 2022. The Author(s).)

Introduction: Extremely preterm (EP)/extremely low birthweight (ELBW) individuals may have an increased risk for adverse cardiovascular outcomes. Compared with term-born controls, these individuals have poorer lung function and reduced exercise capacity. Exercise interventions play an important role in reducing cardiopulmonary risk, however their use in EP/ELBW cohorts is unknown. This study, cardiac cycle, aims to characterise the cardiopulmonary system of children and adolescents who were born EP compared with those born at term, following acute and chronic exercise bouts., Methods and Analysis: The single-centre study comprises a home-based exercise intervention, with physiological characterisation at baseline and after completion of the intervention. Fifty-eight children and adolescents aged 10-18 years who were born EP and/or with ELBW will be recruited. Cardiopulmonary function assessed via measures of blood pressure, arterial stiffness, capillary density, peak oxygen consumption, lung clearance indexes and ventricular structure/function, will be compared with 58 age-matched and sex-matched term-born controls at baseline and post intervention. The intervention will consist of a 10-week stationary cycling programme, utilising Zwift technology., Ethics and Dissemination: The study is approved by the Ethics Committee of the Royal Children's Hospital Melbourne under HREC2019.053. Results will be disseminated via peer-reviewed journal regardless of outcome., Trial Registration Number: 12619000539134, ANZCTR., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

The cabbage stem flea beetle, Psylliodes chrysocephala L. is a major pest of winter oilseed rape in several European countries. Traditionally, neonicotinoid and pyrethroid insecticides have been widely used for control of P. chrysocephala , but in recent years, following the withdrawal of neonicotinoid insecticide seed treatments, control failures have occurred due to an over reliance on pyrethroids. In line with previous surveys, UK populations of P. chrysocephala were found to exhibit high levels of resistance to the pyrethroid lambda-cyhalothrin. This resistance was suppressed by pre-treatment with the cytochrome P450 inhibitor PBO under laboratory conditions, suggesting that the resistance has a strong metabolic component. The L1014F (kdr) mutation in the voltage-gated sodium channel, which confers relatively low levels (10-20 fold) of resistance to pyrethroids, was also found to be widespread across the UK regions sampled, whereas the L925I (s-kdr) mutation was much less common. The current survey also suggests that higher levels of pyrethroid resistance have spread to the North and West of England, and that resistance levels continue to remain high in the South East., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2020 Rothamsted Research.)

The Athabasca Oil Sands Region (AOSR) in Alberta, Canada, is an important source of atmospheric pollutants, such as aerosols, that have repercussions on both the climate and human health. We show that the mean freezing temperature of snow-borne particles from AOSR was elevated (-7.1 ± 1.8 °C), higher than mineral dust which freezes at ∼ -15 °C and is recognized as one of the most relevant ice nuclei globally. Ice nucleation of nanosized snow samples indicated an elevated freezing ability (-11.6 ± 2.0 °C), which was statistically much higher than snow-borne particles from downtown Montreal. AOSR snow had a higher concentration (∼2 orders of magnitude) of >100 nm particles than Montreal. Triple quadrupole ICP-(QQQ)-MS/MS analysis of AOSR and Montreal snow demonstrated that most concentrations of metals, including those identified as emerging nanoparticulate contaminants, were much more elevated in AOSR in contrast to Montreal: 34.1, 34.1, 16.6, 5.8, 0.3, 0.1, and 9.4 mg/m 3 for Cr, Ni, Cu, As, Se, Cd, and Pb respectively, in AOSR and 1.3, 0.3, 2.0, <0.03, 0.1, 0.03, and 1.2 mg/m 3 in Montreal snow. High-resolution Scanning Transmission Electron Microscopy/Energy-dispersive X-ray Spectroscopy (STEM-EDS) imaging provided evidence for various anthropogenic nano-materials, including carbon nanotubes resembling structures, in AOSR snow up to 7-25 km away from major oil sands upgrading facilities. In summary, particles characterized as coming from oil sands are more efficient at ice nucleation. We discuss the potential impacts of AOSR emissions on atmospheric and microphysical processes (ice nucleation and precipitation) both locally and regionally., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Aim: The actions and behaviors of parents have been identified as key factors that influence a child's participation in physical activity. However, there is limited knowledge of how parents can be supported to embody facilitative roles. This study aimed to explore how an ecological intervention encourages parents of children with disabilities to develop as facilitators, to enable ongoing physical activity participation in a child's local environment., Methods: A qualitative design using grounded theory was employed. Forty four parents (26 mothers, 18 fathers) of 31 children with a range of disabilities (mean age 12y 6m (SD 2y 2m); 18 males) partaking in the Local Environment Model intervention at Beitostolen Healthsports Centre in Norway participated in the study. Data were derived from the triangulation of semi-structured interviews and participant observation. Data analysis was an iterative approach of constant comparison, where data collection, memo writing, open, axial and selective coding analysis, were undertaken simultaneously. Findings were consolidated into a model describing the central phenomenon and its relationship to other categories., Results: Thematic concepts uncovered in this study describe a social process of parent learning and empowerment, comprising three primary components; (i) active ingredients of the intervention that enabled learning and empowerment to transpire, (ii) parent learning and empowerment as a process, and (iii) related outcomes., Conclusion: A family-centered approach, encompassing family-to-family support, may enhance physical activity participation outcomes for children and youth with disabilities.

Tailings ponds created during industrial bitumen extraction from the Athabasca Oil Sands Region (AOSR), Alberta, Canada, have been shown to contain numerous contaminants, such as polycyclic aromatic compounds and naphthenic acids, and to slowly leak into adjacent ground and surface waters. Despite elevated concentrations of total mercury (THg) in nearby Athabasca River waters downstream of the AOSR developments, to date there are no published studies of THg or methylmercury (MeHg; a potent neurotoxin) in the AOSR tailings ponds. Here we present concentrations of THg and MeHg, as well as various water chemistry parameters, within four AOSR tailings ponds. Concentrations of SO 4 2- , NH 3 , Na, and Cl were elevated in tailings ponds relative to nearby freshwaters. Surface water concentrations of THg (filtered: 0.15-0.57 ng/L) and MeHg (unfiltered: <0.02-0.53 ng/L; filtered: <0.02-0.32 ng/L), though, were generally low in the tailings ponds, with the highest concentrations observed in the oldest pond. In the mature fine tailings that settle out in the ponds, concentrations of THg (37.0-197 ng/g) and MeHg (0.10-0.52 ng/g) were also low, with the highest concentrations again in the oldest pond. We calculated that if all the dissolved THg and MeHg potentially leaking annually from the tailings ponds entered the nearby Athabasca River, river THg and MeHg concentrations would increase by only 0.01% and 0.03%, respectively. Overall, these ponds are likely not significant sources of THg or MeHg to nearby ground and surface waters, although due to the potential for Hg methylation to occur in the ponds themselves, other tailings ponds in the AOSR should be monitored to ensure that concentrations of MeHg in them are also low., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Purpose: The purpose of this study was to determine whether a proposed suite of objective image quality metrics for digital chest radiographs is useful for monitoring image quality in a clinical setting unique from the one where the metrics were developed., Methods: Seventeen gridless AP chest radiographs from a GE Optima portable digital radiography (DR) unit ("sub-standard" images; Group 2) and 17 digital PA chest radiographs ("standard-of-care" images; Group 1) and 15 gridless (non-routine) PA chest radiographs (images with a gross technical error; Group 3) from a Discovery DR unit were chosen for analysis. Group 2 images were acquired with a lower kVp (100 vs 125) and shorter source-to-image distance (127 cm vs 183 cm) and were expected to have lower quality than Group 1 images. Group 3 images were expected to have degraded contrast vs Group 1 images. Images were anonymized and securely transferred to the Duke University Clinical Imaging Physics Group for analysis using software described and validated previously. Individual image quality was reported in terms of lung gray level, lung detail, lung noise, rib-lung contrast, rib sharpness, mediastinum detail, mediastinum noise, mediastinum alignment, subdiaphragm-lung contrast, and subdiaphragm area. Metrics were compared across groups. To improve precision of means and confidence intervals for routine exams, an additional 66 PA images were acquired, processed, and pooled with Group 1. Three observer studies were conducted to assess whether humans were able to identify images classified by the algorithm as abnormal., Results: Metrics agreed with published Quality Consistency Ranges with three exceptions: higher lung gray level, lower rib-lung contrast, and lower subdiaphragm-lung contrast. Higher (stored) bit depth (14 vs 12) accounted for higher lung gray level values in our images. Values were most internally consistent for Group 1. The most sensitive metric for distinguishing between groups was mediastinum noise, followed closely by lung noise. The least sensitive metrics were mediastinum detail and rib-lung contrast. The algorithm was more sensitive than human observers at detecting suboptimal diagnostic quality images., Conclusions: The software appears promising for objectively and automatically identifying suboptimal images in a clinical imaging operation. The results can be used to establish local quality consistency ranges and action limits per facility preferences., (© 2018 American Association of Physicists in Medicine.)

Purpose: The study illustrates how a renewed approach to medical physics, Medical Physics 3.0 (MP3.0), can identify performance decrement of digital radiography (DR) systems when conventional Medical Physics 1.0 (MP1.0) methods fail., Methods: MP1.0 tests included traditional annual tests plus the manufacturer's automated Quality Assurance Procedures (QAP) of a DR system before and after a radiologist's image quality (IQ) complaint repeated after service intervention. Further analysis was conducted using nontraditional MP3.0 tests including longitudinal review of QAP results from a 15-yr database, exposure-dependent signal-to-noise (SNR 2 ), clinical IQ, and correlation with the institutional service database. Clinical images were analyzed in terms of IQ metrics by the Duke University Clinical Imaging Physics Group using previously validated software., Results: Traditional metrics did not indicate discrepant system performance at any time. QAP reported a decrease in contrast-to-noise ratio (CNR) after detector replacement, but remained above the manufacturer's action limit. Clinical images showed increased lung noise (Ln), mediastinum noise (Mn), and subdiaphragm-lung contrast (SLc), and decreased lung gray level (Lgl) following detector replacement. After detector recalibration, QAP CNR improved, but did not return to previous levels. Lgl and SLc no longer significantly differed from before detector recalibration; however, Ln and Mn remained significantly different. Exposure-dependent SNR 2 documented the detector operating within acceptable limits 9 yr previously but subsequently becoming miscalibrated sometime before four prior annual tests. Service records revealed catastrophic failure of the computer containing the original detector calibration from 11 yr prior. It is likely that the incorrect calibration backup file was uploaded at that time., Conclusions: MP1.0 tests failed to detect substandard system performance, but MP3.0 methods determined the root cause of the problem. MP3.0 exploits the wealth of data with more sensitive performance indicators. Data analytics are powerful tools whose proper application could facilitate early intervention in degraded system performance., (© 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.)

Background: The need to identify strategies that facilitate involvement in physical activity for children and youth with disabilities is recognised as an urgent priority. This study aimed to describe the association between context, mechanisms and outcome(s) of a participation-focused physical activity intervention to understand what works, in what conditions, and how., Methods: This study was designed as a realist evaluation. Participant recruitment occurred through purposive and theoretical sampling of children and parents participating in the Local Environment Model intervention at Beitostolen Healthsports Centre in Norway. Ethnographic methods comprising participant observation, interviews, and focus groups were employed over 15 weeks in the field. Data analysis was completed using the context-mechanism-outcome framework of realist evaluation. Context-mechanism-outcome connections were generated empirically from the data to create a model to indicate how the program activated mechanisms within the program context, to enable participation in physical activity., Results: Thirty one children with a range of disabilities (mean age 12y 6 m (SD 2y 2 m); 18 males) and their parents (n = 44; 26 mothers and 18 fathers) participated in the study. Following data synthesis, a refined program theory comprising four context themes, five mechanisms, and six outcomes, were identified. The mechanisms (choice, fun, friends, specialised health professionals, and time) were activated in a context that was safe, social, learning-based and family-centred, to elicit outcomes across all levels of the International Classification of Functioning, Disability and Health., Conclusions: The interaction of mechanisms and context as a whole facilitated meaningful outcomes for children and youth with disabilities, and their parents. Whilst optimising participation in physical activity is a primary outcome of the Local Environment Model, the refined program theory suggests the participation-focused approach may act as a catalyst to promote a range of outcomes. Findings from this study may inform future interventions attempting to enable participation in physical activity for children and youth with disabilities.

Snowpacks in the Alberta Oil Sands Region (AOSR) of Canada contain elevated loadings of methylmercury (MeHg; a neurotoxin that biomagnifies through foodwebs) due to oil sands related activities. At sites ranging from 0 to 134 km from the major AOSR upgrading facilities, we examined sources of MeHg by quantifying potential rates of MeHg production in snowpacks and melted snow using mercury stable isotope tracer experiments, as well as quantifying concentrations of MeHg on particles in snowpacks (pMeHg). At four sites, methylation rate constants were low in snowpacks (k m = 0.001-0.004 d -1 ) and nondetectable in melted snow, except at one site (k m = 0.0007 d -1 ). The ratio of methylation to demethylation varied between 0.3 and 1.5, suggesting that the two processes are in balance and that in situ production is unlikely an important net source of MeHg to AOSR snowpacks. pMeHg concentrations increased linearly with distance from the upgraders (R 2 = 0.71, p < 0.0001); however, snowpack total particle and pMeHg loadings decreased exponentially over this same distance (R 2 = 0.49, p = 0.0002; R 2 = 0.56, p < 0.0001). Thus, at near-field sites, total MeHg loadings in snowpacks were high due to high particle loadings, even though particles originating from industrial activities were not MeHg rich compared to those at remote sites. More research is required to identify the industrial sources of snowpack particles in the AOSR.

The purpose of this study was to evaluate several of the standardized image quality metrics proposed by the American Association of Physics in Medicine (AAPM) Task Group 150. The task group suggested region-of-interest (ROI)-based techniques to measure nonuniformity, minimum signal-to-noise ratio (SNR), number of anomalous pixels, and modulation transfer function (MTF). This study evaluated the effects of ROI size and layout on the image metrics by using four different ROI sets, assessed result uncertainty by repeating measurements, and compared results with two commercially available quality control tools, namely the Carestream DIRECTVIEW Total Quality Tool (TQT) and the GE Healthcare Quality Assurance Process (QAP). Seven Carestream DRX-1C (CsI) detectors on mobile DR systems and four GE FlashPad detectors in radiographic rooms were tested. Images were analyzed using MATLAB software that had been previously validated and reported. Our values for signal and SNR nonuniformity and MTF agree with values published by other investigators. Our results show that ROI size affects nonuniformity and minimum SNR measurements, but not detection of anomalous pixels. Exposure geometry affects all tested image metrics except for the MTF. TG-150 metrics in general agree with the TQT, but agree with the QAP only for local and global signal nonuniformity. The difference in SNR nonuniformity and MTF values between the TG-150 and QAP may be explained by differences in the calculation of noise and acquisition beam quality, respectively. TG-150's SNR nonuniformity metrics are also more sensitive to detector nonuniformity compared to the QAP. Our results suggest that fixed ROI size should be used for consistency because nonuniformity metrics depend on ROI size. Ideally, detector tests should be performed at the exact calibration position. If not feasible, a baseline should be established from the mean of several repeated measurements. Our study indicates that the TG-150 tests can be used as an independent standardized procedure for detector performance assessment., (© 2016 The Authors.)

We describe three newly isolated phages-Obliviate, UmaThurman, and Guacamole-that infect Gordonia terrae 3612. The three genomes are related to one another but are not closely related to other previously sequenced phages or prophages. The three phages are predicted to use integration-dependent immunity systems as described in several mycobacteriophages., (Copyright © 2016 Pope et al.)

There is a clear need for established standards for medical physics residency training. The complexity of techniques in imaging, nuclear medicine, and radiation oncology continues to increase with each passing year. It is therefore imperative that training requirements and competencies are routinely reviewed and updated to reflect the changing environment in hospitals and clinics across the country. In 2010, the AAPM Work Group on Periodic Review of Medical Physics Residency Training was formed and charged with updating AAPM Report Number 90. This work group includes AAPM members with extensive experience in clinical, professional, and educational aspects of medical physics. The resulting report, AAPM Report Number 249, concentrates on the clinical and professional knowledge needed to function independently as a practicing medical physicist in the areas of radiation oncology, imaging, and nuclear medicine, and constitutes a revision to AAPM Report Number 90. This manuscript presents an executive summary of AAPM Report Number 249.

Misregistration due to cardiac motion causes artifacts in two-exposure dual-energy subtraction images, in both the soft-tissue-only image and the bone-only image. Two previous investigations have attempted to avoid misregistration artifacts by using cardiac gating of the first and second exposures. The severity of misregistration was affected by the heart rate, the time interval between the low- and high-energy exposures, the total duration of the two exposures, and the phase of the cardiac cycle at the start of the exposure sequence. We sought to determine whether a commercial phantom with a simulated beating heart can be used to investigate the factors affecting misregistration in dual-energy chest radiography. We made dual-energy images of the phantom in postero-anterior orientation using the indirect digital radiography system (GE XQ/i). We acquired digital images at heart rates between 40 beats per minute and 120 beats per minute and transferred them to a computer, where the area of the artifact on the silhouette of the heart was measured from both soft-tissue-only and bone-only images. For comparison, we measured misregistration in clinical dual-energy subtraction images by the same method. Generally speaking, without synchronization of the exposure sequence with the cardiac cycle, the area of the misregistration artifact increased with heart rate for both the phantom and clinical images. However, the phantom exaggerated the magnitude of misregistration relative to clinical images. Although this phantom was designed for horizontal operation and computed tomography imaging, it can be used in an upright configuration to simulate heart motion for investigation of dual-energy misregistration artifacts and control.

This study examined functional properties and biocompatibility of glutaraldehyde-fixed bovine articular cartilage over several weeks of incubation at body temperature to investigate its potential use as a resurfacing material in joint arthroplasty. In the first experiment, treated cartilage disks were fixed using 0.02, 0.20 and 0.60% glutaraldehyde for 24h then incubated, along with an untreated control group, in saline for up to 28d at 37°C. Both the equilibrium compressive and tensile moduli increased nearly twofold in treated samples compared to day 0 control, and remained at that level from day 1 to 28; the equilibrium friction coefficient against glass rose nearly twofold immediately after fixation (day 1) but returned to control values after day 7. Live explants co-cultured with fixed explants showed no quantitative difference in cell viability over 28d. In general, no significant differences were observed between 0.20 and 0.60% groups, so 0.20% was deemed sufficient for complete fixation. In the second experiment, cartilage-on-cartilage frictional measurements were performed under a migrating contact configuration. In the treated group, one explant was fixed using 0.20% glutaraldehyde while the apposing explant was left untreated; in the control group both explants were left untreated. From day 1 to 28, the treated group exhibited either no significant difference or slightly lower friction coefficient than the untreated group. These results suggest that a properly titrated glutaraldehyde treatment can reproduce the desired functional properties of native articular cartilage and maintain these properties for at least 28d at body temperature., (© 2013 Published by Elsevier Ltd.)

Introduction: The purpose of this study is to determine whether a performance improvement continuing medical education (PI CME) initiative that utilizes quality improvement (QI) principles is effective in producing sustainable change in practice to improve the screening of patients at risk for osteoporosis., Methodology: A health care center participated in a PI CME program designed to increase appropriate osteoporosis screening. There were eight 1-hour educational sessions for this activity over a 9-month period. Thirteen providers completed all 3 stages of the PI CME program. A variety of other clinicians, in addition to the 13 providers, participated in the educational sessions. Data were collected at the beginning and end of the PI CME activity and at three intervals during the 5 years after the completion of the activity., Results: The percentage of tests for osteoporosis ordered and performed increased significantly from Stage A to Stage C of the PI CME activity and continued to increase after the completion of the PI CME activity. Follow-up data at 4 and 40 months (for ordering and performing osteoporosis screening) and 49 months (for performing the screening only) reflect the impact of the PI CME activity plus the continuing QI interventions. The percentage of BMD tests ordered continued to increase substantially over the post-PI CME periods: 4 and 40 months (F(3,46) = 4.04, p < .05). Similarly, the percentage of BMD tests performed continued to increase at 4, 40, and 49 months after the conclusion of the PI CME activity (F(4,55) = 12.55, p < .0001)., Discussion: The data indicate that PI CME utilizing QI principles can be effective in producing sustainable change in practice to improve the screening of patients at risk for osteoporosis. Further research is needed to determine the extent to which such changes can be directly attributed to this type of intervention., (Copyright © 2013 The Alliance for Continuing Education in the Health Professions, the Society for Academic Continuing Medical Education, and the Council on CME, Association for Hospital Medical Education.)

Quantitative measurements of cartilage wear have been challenging, with no method having yet emerged as a standard. This study tested the hypothesis that latest-generation particle analyzers are capable of detecting cartilage wear debris generated during in vitro loading experiments that last 24 h or less, by producing measurable content significantly above background noise levels otherwise undetectable through standard biochemical assays. Immature bovine cartilage disks (4 mm diameter, 1.3 mm thick) were tested against glass using reciprocal sliding under unconfined compression creep for 24 h. Control groups were used to assess various sources of contamination. Results demonstrated that cartilage samples subjected to frictional loading produced particulate volume significantly higher than background noise and contamination levels at all tested time points (1, 2, 6, and 24 h, p < 0.042). The particle counter was able to detect very small levels of wear (less than 0.02% of the tissue sample by volume), whereas no significant differences were observed in biochemical assays for collagen or glycosaminoglycans among any of the groups or time points. These findings confirm that latest-generation particle analyzers are capable of detecting very low wear levels in cartilage experiments conducted over a period no greater than 24 h.

Purpose: The conditions under which vendor performance criteria for digital radiography systems are obtained do not adequately simulate the conditions of actual clinical imaging with respect to radiographic technique factors, scatter production, and scatter control. Therefore, the relationship between performance under ideal conditions and performance in clinical practice remains unclear. Using data from a large complement of systems in clinical use, the authors sought to develop a method to establish expected performance criteria for digital flat-panel radiography systems with respect to signal-to-noise ratio (SNR) versus detector exposure under clinical conditions for thoracic imaging., Methods: The authors made radiographic exposures of a patient-equivalent chest phantom at 125 kVp and 180 cm source-to-image distance. The mAs value was modified to produce exposures above and below the mAs delivered by automatic exposure control. Exposures measured free-in-air were corrected to the imaging plane by the inverse square law, by the attenuation factor of the phantom, and by the Bucky factor of the grid for the phantom, geometry, and kilovolt peak. SNR was evaluated as the ratio of the mean to the standard deviation (SD) of a region of interest automatically selected in the center of each unprocessed image. Data were acquired from 18 systems, 14 of which were tested both before and after gain and offset calibration. SNR as a function of detector exposure was interpolated using a double logarithmic function to stratify the data into groups of 0.2, 0.5, 1.0, 2.0, and 5.0 mR exposure (1.8, 4.5, 9.0, 18, and 45 microGy air KERMA) to the detector., Results: The mean SNR at each exposure interval after calibration exhibited linear dependence on the mean SNR before calibration (r2=0.9999). The dependence was greater than unity (m = 1.101 +/- 0.006), and the difference from unity was statistically significant (p <0.005). The SD of mean SNR after calibration also exhibited linear dependence on the SD of the mean SNR before calibration (r2 = 0.9997). This dependence was less than unity (m = 0.822 +/- 0.008), and the difference from unity was also statistically significant (p < 0.005). Systems were separated into two groups: systems with a precalibration SNR higher than the median SNR (N = 7), and those with a precalibration SNR lower than the median SNR (N= 7). Posthoc analysis was performed to correct for expanded false positive results. After calibration, the authors noted differences in mean SNR within both high and low groups, but these differences were not statistically significant at the 0.05 level. SNR data from four additional systems and one system from those previously tested after replacement of its detector were compared to the 95% confidence intervals (CI) calculated from the postcalibration SNR data. The comparison indicated that four of these five systems were consistent with the CI derived from the previously tested 14 systems after calibration. Two systems from the paired group that remained outside the CI were studied further. One system was remedied with a grid replacement. The nonconformant behavior of the other system was corrected by replacing the image receptor., Conclusions: Exposure-dependent SNR measurements under conditions simulating thoracic imaging allowed us to develop criteria for digital flat-panel imaging systems from a single manufacturer. These measurements were useful in identifying systems with discrepant performance, including one with a defective grid, one with a defective detector, and one that had not been calibrated for gain and offset. The authors also found that the gain and offset calibration reduces variation in exposure-dependent SNR performance among the systems.

Rejected images represent both unnecessary radiation exposure to patients and inefficiency in the imaging operation. Rejected images are inherent to projection radiography, where patient positioning and alignment are integral components of image quality. Patient motion and artifacts unique to digital image receptor technology can result in rejected images also. We present a centralized, server-based solution for the collection, archival, and distribution of rejected image and exposure indicator data that automates the data collection process. Reject analysis program (RAP) and exposure indicator data were collected and analyzed during a 1-year period. RAP data were sorted both by reason for repetition and body part examined. Data were also stratified by clinical area for further investigation. The monthly composite reject rate for our institution fluctuated between 8% and 10%. Positioning errors were the main cause of repeated images (77.3%). Stratification of data by clinical area revealed that areas where computed radiography (CR) is seldom used suffer from higher reject rates than areas where it is used frequently. S values were log-normally distributed for examinations performed under either manual or automatic exposure control. The distributions were positively skewed and leptokurtic. S value decreases due to radiologic technology student rotations, and CR plate reader calibrations were observed. Our data demonstrate that reject analysis is still necessary and useful in the era of digital imaging. It is vital though that analysis be combined with exposure indicator analysis, as digital radiography is not self-policing in terms of exposure. When combined, the two programs are a powerful tool for quality assurance.

Pediatric projection imaging differs from imaging of the adult patient. Children are smaller, more radiosensitive, and less compliant than their adult counterparts. Their characteristics affect the way projection imaging is practiced and how dose is optimized. Computed radiography (CR) and digital radiography (DR) have been embraced by pediatric practitioners in order to reduce dose and improve image quality. Unfortunately, dose optimization with CR and DR has been hampered by a lack of definition of appropriate exposure levels, a lack of standardization in exposure factor feedback, and a lack of understanding of the fundamentals of CR and DR technology. The potential for over-exposure exists with both CR and DR. Both the Society for Pediatric Radiology and the American Association of Physicists in Medicine recognize the promise and shortcomings of CR and DR technology and have taken steps to join with manufacturers in improving the practice of CR and DR imaging. Although the risks inherent in pediatric projection imaging with CR and DR are low, efforts to reduce dose are worthwhile, so long as diagnostic quality is maintained. Long-standing recommendations for limiting radiation dose in pediatric projection imaging are still applicable to CR and DR.

Digital radiographic imaging systems, such as those using photostimulable storage phosphor, amorphous selenium, amorphous silicon, CCD, and MOSFET technology, can produce adequate image quality over a much broader range of exposure levels than that of screen/film imaging systems. In screen/film imaging, the final image brightness and contrast are indicative of over- and underexposure. In digital imaging, brightness and contrast are often determined entirely by digital postprocessing of the acquired image data. Overexposure and underexposures are not readily recognizable. As a result, patient dose has a tendency to gradually increase over time after a department converts from screen/film-based imaging to digital radiographic imaging. The purpose of this report is to recommend a standard indicator which reflects the radiation exposure that is incident on a detector after every exposure event and that reflects the noise levels present in the image data. The intent is to facilitate the production of consistent, high quality digital radiographic images at acceptable patient doses. This should be based not on image optical density or brightness but on feedback regarding the detector exposure provided and actively monitored by the imaging system. A standard beam calibration condition is recommended that is based on RQA5 but uses filtration materials that are commonly available and simple to use. Recommendations on clinical implementation of the indices to control image quality and patient dose are derived from historical tolerance limits and presented as guidelines.

Radiographic techniques are devised on the basis of anatomic dimensions. Inaccurate dimensions can cause radiographs to be exposed inappropriately and patient radiation exposures to be calculated incorrectly. The source of anatomic dimensions in common usage dates back to 1948. The objective of this study was to compare traditional and modern anthropometric data, use modern dimensions to estimate potential errors in patient exposure, and suggest modified technique guidelines. Anthropometry software was used to derive modern anatomic dimensions. Data from routine annual testing were analyzed to develop an x-ray generator output curve. Published tabulated data were used to determine the relationship between tissue half-value layer and kilovoltage. These relationships were used to estimate entrance skin exposure and create a provisional technique guide. While most anatomic regions were actually larger than previously indicated, some were similar, and a few were smaller. Accordingly, exposure estimates were higher, similar, or lower, depending on the anatomic region. Exposure estimates using modern dimensions for clinically significant regions of the trunk were higher than those calculated with traditional dimensions. Exposures of the postero-anterior chest, lateral chest, antero-posterior (AP) abdomen, male AP pelvis, and female AP pelvis were larger by 48%, 31%, 54%, 52%, and 112%, respectively. The dimensions of bony regions of the anatomy, such as the joints and skull, were unchanged. These findings are consistent with the idea that anatomic areas where fat is deposited are larger in the modern U.S. population than they were in previous years. Exposure techniques for manual radiography and calculations of patient dose for automatic exposure control radiography should be adjusted according to the modern dimensions. Population radiation exposure estimates calculated in national surveys should also be modified appropriately.

This paper describes the procedure for using a Fuji computed radiography (CR) imaging plate (IP) for the measurement of computed tomography (CT) radiation profiles. Two sources of saturation in the data from the IP, signal and quantization, were characterized to establish appropriate exposure and processing conditions for accurate measurements. The IP generated similar profiles compared to those obtained from digitized ready-pack films, except at the profile edges, where the exposure level is low. However, when IP pixel values are converted to exposure, CR and digitized film profiles are in agreement. The full width at half maximum (FWHM) of the CT radiation profile was determined from the relationship between pixel value and exposure and compared to FWHM of the digitized optical density profile from film. To estimate the effect of scattering by the cassette material, radiation profiles were acquired from IPs enclosed in a cassette or in a paper envelope. The presence of the cassette made no difference in the value determined for FWHM. With proper exposure and processing conditions, the FWHM of 5, 10, and 15 mm collimated beams were measured using IPs to be 7.1, 11.9, and 17.0 mm and using film to be 7.2, 12.2, and 16.8 mm, respectively. Our results suggest that, under appropriate conditions, the estimation of the width of the CT radiation profile using Fuji CR is comparable to the measurement from film density described in American Association of Physicists in Medicine (AAPM) Report No. 39. Although our experiment was conducted using Fuji CR, we anticipate that CR plates from other vendors could be successfully used to measure CT beam profiles because of similar empirical relationships between pixel value and exposure.

In its ongoing support of continuous physician professional development, the American Medical Association (AMA) for use in the AMA Physician's Recognition Award has adopted 2 new learning platforms: Performance Improvement (PI) and Internet Point of Care (PoC). This article highlights the process that led to their adoption and places these new forms of continuing and physician professional development in the framework of existing continuing medical education (CME). The article calls for new research that revisits existing data on physician learning and prepares to incorporate provider experience with "practice situated" forms of CME. The Conjoint Committee on CME may serve as an important contributor to this process by enabling valuable dialogue among stakeholder organizations.

Digital imaging provides an effective means to electronically acquire, archive, distribute, and view medical images. Medical imaging display stations are an integral part of these operations. Therefore, it is vitally important to assure that electronic display devices do not compromise image quality and ultimately patient care. The AAPM Task Group 18 (TG18) recently published guidelines and acceptance criteria for acceptance testing and quality control of medical display devices. This paper is an executive summary of the TG18 report. TG18 guidelines include visual, quantitative, and advanced testing methodologies for primary and secondary class display devices. The characteristics, tested in conjunction with specially designed test patterns (i.e., TG18 patterns), include reflection, geometric distortion, luminance, the spatial and angular dependencies of luminance, resolution, noise, glare, chromaticity, and display artifacts. Geometric distortions are evaluated by linear measurements of the TG18-QC test pattern, which should render distortion coefficients less than 2%/5% for primary/secondary displays, respectively. Reflection measurements include specular and diffuse reflection coefficients from which the maximum allowable ambient lighting is determined such that contrast degradation due to display reflection remains below a 20% limit and the level of ambient luminance (Lamb) does not unduly compromise luminance ratio (LR) and contrast at low luminance levels. Luminance evaluation relies on visual assessment of low contrast features in the TG18-CT and TG18-MP test patterns, or quantitative measurements at 18 distinct luminance levels of the TG18-LN test patterns. The major acceptable criteria for primary/ secondary displays are maximum luminance of greater than 170/100 cd/m2, LR of greater than 250/100, and contrast conformance to that of the grayscale standard display function (GSDF) of better than 10%/20%, respectively. The angular response is tested to ascertain the viewing cone within which contrast conformance to the GSDF is better than 30%/60% and LR is greater than 175/70 for primary/secondary displays, or alternatively, within which the on-axis contrast thresholds of the TG18-CT test pattern remain discernible. The evaluation of luminance spatial uniformity at two distinct luminance levels across the display faceplate using TG18-UNL test patterns should yield nonuniformity coefficients smaller than 30%. The resolution evaluation includes the visual scoring of the CX test target in the TG18-QC or TG18-CX test patterns, which should yield scores greater than 4/6 for primary/secondary displays. Noise evaluation includes visual evaluation of the contrast threshold in the TG18-AFC test pattern, which should yield a minimum of 3/2 targets visible for primary/secondary displays. The guidelines also include methodologies for more quantitative resolution and noise measurements based on MTF and NPS analyses. The display glare test, based on the visibility of the low-contrast targets of the TG18-GV test pattern or the measurement of the glare ratio (GR), is expected to yield scores greater than 3/1 and GRs greater than 400/150 for primary/secondary displays. Chromaticity, measured across a display faceplate or between two display devices, is expected to render a u',v' color separation of less than 0.01 for primary displays. The report offers further descriptions of prior standardization efforts, current display technologies, testing prerequisites, streamlined procedures and timelines, and TG18 test patterns.

Uncoupling of display from acquisition in computed radiography (CR) and digital radiography (DR) introduces the potential for systematic overexposure without necessarily compromising image quality. Although the magnitude of radiation doses in general radiography is low compared to computed tomography and fluoroscopy, the dose to the patient is more critical in pediatric examinations than in adults, because of the greater radiosensitivity of children. This manuscript examines a variety of countermeasures for managing radiation doses in pediatric CR and DR examinations, including use of derived exposure indicators, modifications of imaging practice, and development of more efficient radiographic detectors.

The two major continuing medical education (CME) credit systems for allopathic physicians in the United States are administered by the American Medical Association (AMA) and the American Academy of Family Physicians (AAFP). This article explores the history of AMA and AAFP CME credit and its value to physicians and the patients they serve. Historically, CME credit has been awarded as hours for participation, but this approach is inadequate as a measure of CME and its impact on improving physician practice. New credit systems are needed to measure a CME activity by its value in bettering the physician's knowledge base, competence, and performance in practice.

The aim of this work was to implement the DICOM Grayscale Standard Display Function (GSDF) at all stages of image presentation for computed radiography (CR) and direct digital radiography (DR) modalities. Cathode-ray tubes (CRT) were calibrated according to vendor procedures. Printer look-up-tables (LUT) were measured. Custom LUTs were created and loaded. Fuji CR gradation processing parameters were adjusted to accommodate a GSDF printer LUT. Conformance to the GSDF for hard-copy and soft-copy displays was measured with DICOM Part 14 procedures. One system was intended to completely incorporate the GSDF, although the hard-copy result was correct. The CR systems required creation of custom GSDF printer LUTs, adjustment of gradation processing parameters, and/or calibration of CRT luminance response at the quality control station. The picture archiving and communication system workstations from one vendor required third-party software for calibration. Current implementations of DICOM GSDF by vendors may be inconsistent or nonexistent. Significant effort by in-house staff must be expended to properly incorporate the GSDF.

Recommended methods to test the performance of computed radiography (CR) digital radiographic systems have been recently developed by the AAPM Task Group No. 10. Included are tests for dark noise, uniformity, exposure response, laser beam function, spatial resolution, low-contrast resolution, spatial accuracy, erasure thoroughness, and throughput. The recommendations may be used for acceptance testing of new CR devices as well as routine performance evaluation checks of devices in clinical use. The purpose of this short communication is to provide a tabular summary of the tests recommended by the AAPM Task Group, delineate the technical aspects of the tests, suggest quantitative measures of the performance results, and recommend uniform quantitative criteria for the satisfactory performance of CR devices. The applicability of the acceptance criteria is verified by tests performed on CR systems in clinical use at five different institutions. This paper further clarifies the recommendations with respect to the beam filtration to be used for exposure calibration of the system, and the calibration of automatic exposure control systems.

Background: The aim of this study was to explore the differences in the incidence of primary elective total hip replacements between urban and rural communities and different age and sex groups in Northern Ireland, and to use this information to develop an equitable method for the allocation of surgical capacity among groups of general practices, in a system where referrals are matched to the contracted capacity., Methods: A retrospective review was performed of all cases of primary elective total hip replacement between 1 April 1994 and 31 March 1997. Incidence rates were calculated using direct standardization. Age, sex, and urban and rural specific rates for Northern Ireland were calculated and applied to each general practice population giving that practice's annual expected number of total hip replacements., Results: A total of 4,147 cases were analysed. The age and sex standardized incidence of primary elective total hip replacement for the total population was 87.6 per 100,000. The incidence was significantly greater in rural populations (101.3 per 100,000), than in urban ones (77.6 per 100,000), p < 0.001. The overall standardized ratio of males to females was 1:1 although it was 1:1.2 in urban and 1:0.9 in rural populations. Using a 3 year commissioning cycle, commissioning for a population of 130,000 allows a 10 per cent margin of error in the numbers of procedures required., Conclusions: A system of calculating the expected need for a total hip replacements was developed based on the demography and rurality of individual general practices. This system allowed a method of commissioning to be instituted that could significantly reduce in-patient waiting lists for this procedure.

Background: Hypernatremic dehydration in neonates is a potentially devastating condition. Recent reports have identified breast-feeding malnutrition as a key factor in its pathophysiology., Methods: Using a theoretical framework for breast-feeding kinetics, a retrospective chart review of all neonates less than 28 days of age who were seen at either British Columbia's Children's Hospital or the Vancouver Breastfeeding Centre between 1991-1994 was conducted to identify and classify possible causes of breast-feeding malnutrition among neonates who developed hypernatremic dehydration., Results: Twenty-one cases hypernatremic dehydration were identified. Infant weight loss ranged from 8% to 30% of birth weight, and serum sodium levels ranged from 146 mmol/L to 207 mmol/L. In each case, maternal or infant factors (e.g., poor breast-feeding technique, lactation failure following postpartum hemorrhage and infant suckling disorders associated with cleft palate or ankyloglossia) that could interfere with either lactation or breast-feeding dynamics and account for insufficient breast milk intake were identified., Interpretation: Prenatal and in-hospital screening for maternal and infant risk factors for breast-feeding malnutrition combined with early postpartum follow-up to detect excessive infant weight loss are important for the prevention of neonatal hypernatremic dehydration.

Aims/background: With the ageing population, numbers of glaucoma patients are an increasing problem in ophthalmic outpatient clinics. A postal questionnaire survey was carried out in Northern Ireland with the aim of finding out how well placed optometrists are to become involved in the monitoring of glaucoma., Results: Of the 171 practices surveyed, 68% of the senior practitioners responded. One practice was without a tonometer and one practice was without visual field instrumentation. Age criteria were used by 95% of practitioners for measuring intraocular pressure (IOP) and 82% used appropriate selection criteria for visual field testing. An IOP of 25 or 26 mmHg was used by 45% of practitioners as the level for referral if there are no risk factors; 89% would refer at any level if a visual field defect and disc cupping were present., Conclusion: The results confirm that the majority of optometrists are well equipped for the screening of glaucoma. However a significant investment in training and equipment would be required if any sort of shared care scheme were to be introduced.