bluuebunny/crossref_metadata_2025_split huggingface dataset:
A gate evaluation of the sources of error in quantitative90Y PET
Authors: Strydhorst Jared , Carlier Thomas , Dieudonné Arnaud , Conti Maurizio , Buvat Irène 
Published: September 2016

PurposeAccurate reconstruction of the dose delivered by 90Y microspheres using a postembolization PET scan would permit the establishment of more accurate dose–response relationships for treatment of hepatocellular carcinoma with 90Y. However, the quality of the PET data obtained is compromised by several factors, including poor count statistics and a very high random fraction. This work uses Monte Carlo simulations to investigate what impact factors other than low count statistics have on the quantification of90Y PET.MethodsPET acquisitions of two phantoms—a NEMA PET phantom and the NEMA IEC PET body phantom‐containing either 90Y or 18F were simulated using gate. Simulated projections were created with subsets of the simulation data allowing the contributions of random, scatter, and LSO background to be independently evaluated. The simulated projections were reconstructed using the commercial software for the simulated scanner, and the quantitative accuracy of the reconstruction and the contrast recovery of the reconstructed images were evaluated.ResultsThe quantitative accuracy of the 90Y reconstructions were not strongly influenced by the high random fraction present in the projection data, and the activity concentration was recovered to within 5% of the known value. The contrast recovery measured for simulated 90Y data was slightly poorer than that for simulated 18F data with similar count statistics. However, the degradation was not strongly linked to any particular factor. Using a more restricted energy range to reduce the random fraction in the projections had no significant effect.ConclusionsSimulations of 90Y PET confirm that quantitative 90Y is achievable with the same approach as that used for 18F, and that there is likely very little margin for improvement by attempting to model aspects unique to 90Y, such as the much higher random fraction or the presence of bremsstrahlung in the singles data.
Technical Note: scuda: A software platform for cumulative dose assessment
Authors: Park Seyoun , McNutt Todd , Plishker William , Quon Harry , Wong John , Shekhar Raj , Lee Junghoon 
Published: September 2016

PurposeAccurate tracking of anatomical changes and computation of actually delivered dose to the patient are critical for successful adaptive radiation therapy (ART). Additionally, efficient data management and fast processing are practically important for the adoption in clinic as ART involves a large amount of image and treatment data. The purpose of this study was to develop an accurate and efficient Software platform for CUmulative Dose Assessment (scuda) that can be seamlessly integrated into the clinical workflow.Methodsscuda consists of deformable image registration (DIR), segmentation, dose computation modules, and a graphical user interface. It is connected to our image PACS and radiotherapy informatics databases from which it automatically queries/retrieves patient images, radiotherapy plan, beam data, and daily treatment information, thus providing an efficient and unified workflow. For accurate registration of the planning CT and daily CBCTs, the authors iteratively correct CBCT intensities by matching local intensity histograms during the DIR process. Contours of the target tumor and critical structures are then propagated from the planning CT to daily CBCTs using the computed deformations. The actual delivered daily dose is computed using the registered CT and patient setup information by a superposition/convolution algorithm, and accumulated using the computed deformation fields. Both DIR and dose computation modules are accelerated by a graphics processing unit.ResultsThe cumulative dose computation process has been validated on 30 head and neck (HN) cancer cases, showing 3.5 ± 5.0 Gy (mean±STD) absolute mean dose differences between the planned and the actually delivered doses in the parotid glands. On average, DIR, dose computation, and segmentation take 20 s/fraction and 17 min for a 35‐fraction treatment including additional computation for dose accumulation.ConclusionsThe authors developed a unified software platform that provides accurate and efficient monitoring of anatomical changes and computation of actually delivered dose to the patient, thus realizing an efficient cumulative dose computation workflow. Evaluation on HN cases demonstrated the utility of our platform for monitoring the treatment quality and detecting significant dosimetric variations that are keys to successful ART.
Reference‐based MRI
Authors: Weizman Lior , Eldar Yonina C. , Ben Bashat Dafna 
Published: September 2016

PurposeIn many clinical MRI scenarios, existing imaging information can be used to significantly shorten acquisition time or to improve Signal to Noise Ratio (SNR). In this paper the authors present a framework, referred to as FASTMER, for fast MRI by exploiting a reference image.MethodsThe proposed approach utilizes the possible similarity of the reference image to the acquired image, which exists in many clinical MRI imaging scenarios. Examples include similarity between adjacent slices in high resolution MRI, similarity between various contrasts in the same scan and similarity between different scans of the same patient. To account for the fact that the reference image may exhibit low similarity with the acquired image the authors develop an iterative weighted reconstruction approach, which tunes the weights according to the degree of similarity.ResultsExperimental results demonstrate the performance of the method in three different clinical MRI scenarios: The first example demonstrates SNR improvement in high resolution brain MRI, the second scenario exploits similarity between T2‐weighted and fluid‐attenuated inversion recovery (FLAIR) for fast FLAIR scanning and the last application utilizes similarity between baseline and follow‐up scans for fast follow‐up acquisition. The results show that FASTMER outperforms image reconstruction of existing state‐of‐the‐art methods.ConclusionsThe authors present a framework for fast MRI by exploiting a reference image. Recovery is based on an iterative algorithm that supports cases in which similarity to the reference scan is not guaranteed. This extends the applicability of the FASTMER to different MRI scanning scenarios. Thanks to the existence of reference images in various clinical imaging tasks, the proposed framework can play a major role in improving reconstruction in many MR applications.
Assessing Overreaching With Heart-Rate Recovery: What Is the Minimal Exercise Intensity Required?
Authors: Le Meur Yann , Buchheit Martin , Aubry Anaël , Coutts Aaron J , Hausswirth Christophe 
Published: September 2016

Purpose:Faster heart-rate recovery (HRR) after high to maximal exercise (≥90% of maximal heart rate) has been reported in athletes suspected of functional overreaching (f-OR). This study investigated whether this response would also occur at lower exercise intensity.Methods:Responses of HRR and rating of perceived exertion (RPE) were compared during an incremental intermittent running protocol to exhaustion in 20 experienced male triathletes (8 control subjects and 13 overload subjects led to f-OR) before and immediately after an overload training period and after a 1-wk taper.Results:Both groups demonstrated an increase in HRR values immediately after the training period, but this change was very likely to almost certainly larger in the f-OR group at all running intensities (large to very large differences, eg, +16 ± 7 vs +3 ± 5 beats/min, in the f-OR and control groups at 11 km/h, respectively). The highest between-groups differences in changes in HRR were reported at 11 km/h (13 ± 4 beats/min) and 12 km/h (10 ± 6 beats/min). A concomitant increase in RPE at all intensities was reported only in the f-OR group (large to extremely large differences, +2.1 ± 1.5 to +0.7 ± 1.5 arbitrary units).Conclusion:These findings confirm that faster HRR does not systematically predict better physical performance. However, when interpreted in the context of the athletes’ fatigue state and training phase, HRR after submaximal exercise may be more discriminant than HRR measures taken after maximal exercise for monitoring f-OR. These findings may be applied in practice by regularly assessing HRR after submaximal exercise (ie, warm-up) for monitoring endurance athletes’ responses to training.
A Comparison of Physical and Technical Performance Profiles Between Successful and Less-Successful Professional Rugby League Teams
Authors: Kempton Thomas , Sirotic Anita C. , Coutts Aaron J. 
Published: September 2016

Purpose:To examine differences in physical and technical performance profiles using a large sample of match observations drawn from successful and less-successful professional rugby league teams.Methods:Match activity profiles were collected using global positioning satellite (GPS) technology from 29 players from a successful rugby league team during 24 games and 25 players from a less-successful team during 18 games throughout 2 separate competition seasons. Technical performance data were obtained from a commercial statistics provider. A progressive magnitude-based statistical approach was used to compare differences in physical and technical performance variables between the reference teams.Results:There were no clear differences in playing time, absolute and relative total distances, or low-speed running distances between successful and less-successful teams. The successful team possibly to very likely had lower higher-speed running demands and likely had fewer physical collisions than the less-successful team, although they likely to most likely demonstrated more accelerations and decelerations and likely had higher average metabolic power. The successful team very likely gained more territory in attack, very likely had more possessions, and likely committed fewer errors. In contrast, the less-successful team was likely required to attempt more tackles, most likely missed more tackles, and very likely had a lower effective tackle percentage.Conclusions:In the current study, successful match performance was not contingent on higher match running outputs or more physical collisions; rather, proficiency in technical performance components better differentiated successful and less-successful teams.
Understanding the Mismatch Between Coaches’ and Players’ Perceptions of Exertion
Authors: Brink Michel S. , Kersten Anna W. , Frencken Wouter G.P. 
Published: September 2016

A mismatch between the training exertion intended by a coach and the exertion perceived by players is well established in sports. However, it is unknown whether coaches can accurately observe exertion of individual players during training. Furthermore, the discrepancy in coaches’ and players’ perceptions has not been explained.Purpose:To determine the relation between intended and observed training exertion by the coach and perceived training exertion by the players and establish whether on-field training characteristics, intermittent endurance capacity, and maturity status explain the mismatch.Methods:During 2 mesocycles of 4 wk (in November and March), rating of intended exertion (RIE), rating of observed exertion (ROE), and rating of perceived exertion (RPE) were monitored in 31 elite young soccer players. External and internal training loads were objectively quantified with accelerometers (PlayerLoad) and heart-rate monitors (TRIMPmod). Results of an interval shuttle-run test (ISRT) and age at peak height velocity (APHV) were determined for all players.Results:RIE, ROE, and RPE were monitored in 977 training sessions. The correlations between RIE and RPE (r = .58; P < .01) and between ROE and RPE (r = .64; P < .01) were moderate. The mean difference between RIE and RPE was –0.31 ± 1.99 and between ROE and RPE was –0.37 ± 1.87. Multilevel analyses showed that PlayerLoad and ISRT predicted RIE and ROE.Conclusion:Coaches base their intended and observed exertion on what they expect players will do and what they actually did on the field. When doing this, they consider the intermittent endurance capacity of individual players.
Morning Exercise: Enhancement of Afternoon Sprint-Swimming Performance
Authors: McGowan Courtney J. , Pyne David B. , Thompson Kevin G. , Raglin John S. , Rattray Ben 
Published: September 2016

Context:An exercise bout completed several hours prior to an event may improve competitive performance later that same day.Purpose:To examine the influence of morning exercise on afternoon sprint-swimming performance.Methods:Thirteen competitive swimmers (7 male, mean age 19 ± 3 y; 6 female, mean age 17 ± 3 y) completed a morning session of 1200 m of variedintensity swimming (SwimOnly), a combination of varied-intensity swimming and a resistance-exercise routine (SwimDry), or no morning exercise (NoEx). After a 6-h break, swimmers completed a 100-m time trial.Results:Time-trial performance was faster in SwimOnly (1.6% ± 0.6, mean ± 90% confidence limit, P < .01) and SwimDry (1.7% ± 0.7%, P < .01) than in NoEx. Split times for the 25- to 50-m distance were faster in both SwimOnly (1.7% ± 1.2%, P = .02) and SwimDry (1.5% ± 0.8%, P = .01) than in NoEx. The first 50-m stroke rate was higher in SwimOnly (0.70 ± 0.21 Hz, mean ± SD, P = .03) and SwimDry (0.69 ± 0.18 Hz, P = .05) than in NoEx (0.64 ± 0.16 Hz). Before the afternoon session, core (0.2°C ± 0.1°C [mean ± 90% confidence limit], P = .04), body (0.2°C ± 0.1°C, P = .02), and skin temperatures (0.3°C ± 0.3°C, P = .02) were higher in SwimDry than in NoEx.Conclusions:Completion of a morning swimming session alone or together with resistance exercise can substantially enhance sprint-swimming performance completed later the same day.
Effect of Retraining Approach-Avoidance Tendencies on an Exercise Task: A Randomized Controlled Trial
Authors: Cheval Boris , Sarrazin Philippe , Pelletier Luc , Friese Malte 
Published: September 2016

Background:Promoting regular physical activity (PA) and lessening sedentary behaviors (SB) constitute a public health priority. Recent evidence suggests that PA and SB are not only related to reflective processes (eg, behavioral intentions), but also to impulsive approach-avoidance tendencies (IAAT). This study aims to test the effect of a computerized IAAT intervention on an exercise task.Methods:Participants (N = 115) were randomly assigned to 1 of 3 experimental conditions, in which they were either trained to approach PA and avoid SB (ApPA-AvSB condition), to approach SB and avoid PA (ApSB-AvPA condition), or to approach and avoid PA and SB equally often (active control condition). The main outcome variable was the time spent carrying out a moderate intensity exercise task.Results:IAAT toward PA decreased in the ApSB-AvPA condition, tended to increase in the ApPA-AvSB condition, and remained stable in the control condition. Most importantly, the ApPA-AvSB manipulation led to more time spent exercising than the ApSB-AvPA condition. Sensitivity analyses excluding individuals who were highly physically active further revealed that participants in the ApPA-AvSB condition spent more time exercising than participants in the control condition.Conclusions:These findings provide preliminary evidence that a single intervention session can successfully change impulsive approach tendencies toward PA and can increase the time devoted to an exercise task, especially among individuals who need to be more physically active. Potential implications for health behavior theories and behavior change interventions are outlined.
Physical Activity Status in Patients With Coronary Heart Disease: Results From the Cross-Sectional EUROASPIRE Surveys
Authors: De Smedt Delphine , Clays Els , Prugger Christof , De Sutter Johan , Fras Zlatko , De Backer Guy , Lovic Dragan , Baert Anneleen , Kotseva Kornelia , De Bacquer Dirk 
Published: September 2016

Background:The study aim was to assess the physical activity levels as well as the intention to become physically active in patients with stable coronary heart disease (CHD) with a special focus on the association with their risk profile.Methods:Analyses are based on the cross-sectional EUROASPIRE IV surveys. Information was available on 8966 patients in EUROASPIRE III and on 7998 patients in EUROASPIRE IV. Physical activity level according to patients risk profile and their medical management was assessed, the intention to become physically active was investigated and a time trend analysis was performed.Results:A better cardiovascular risk profile as well as receiving physical activity advice or weight loss advice was associated with better physical activity levels. The physical activity status improved significantly over time, the proportion of patients reporting vigorous physical activity for at least 20 minutes ≥ 3 times/week increased from 14.1% to 20.2% (P < .001). Similarly, a significantly greater proportion of patients are in the maintenance stage (36.6% vs. 27.4%) and a smaller proportion in the precontemplation stage (43.2% vs. 52.3%).Conclusion:Although an increase was seen in the proportion of patients being adequately physical active, physical activity levels remain suboptimal in many CHD patients.
Associations Between Cardiorespiratory Fitness and Overweight With Academic Performance in 12-Year-Old Brazilian Children
Authors: de Almeida Santana Carla Caroliny , Farah Breno Quintella , de Azevedo Liane Beretta , Hill James O. , Gunnarsdottir Thrudur , Botero João Paulo , do Prado Edna Cristina , do Prado Wagner Luiz 
Published: September 2016

Obesity has been associated with poor academic achievement, while cardiorespiratory fitness (CRF) has been linked to academic success.Purpose:To investigate whether CRF is associated with academic performance in Brazilian students, independently of body mass index (BMI), fatness and socioeconomic status (SES).Methods:392 5th and 6th grade students (193 girls) (12.11 ± 0.75 years old) were evaluated in 2012. Skinfold thickness measures were performed, and students were classified according to BMI-percentile. CRF was estimated by a 20-meter shuttle run test, and academic achievement by standardized math and Portuguese tests. Multiple linear regression analyses were conducted to explore the association between academic performance and CRF, adjusted for SES, skinfold thickness or BMI-percentile.Results:Among girls CRF was associated with higher academic achievement in math (β = 0.146;p = .003) and Portuguese (β = 0.129;p = .004) in crude and adjusted analyses. No significant association was found among boys. BMI was not associated with overall academic performance. There was a weak negative association between skinfold thickness and performance in mathematics in boys (β =- 0.030;p = .04), but not in girls.Conclusion:The results highlight the importance of maintaining high fitness levels in girls throughout adolescence a period commonly associated with reductions in physical activity levels and CRF.
The Effect of Steroid Hormones on the Physical Performance of Boys and Girls During an Olympic Weightlifting Competition
Authors: Crewther Blair , Obminski Zbigniew , Cook Christian 
Published: September 2016

Purpose:To examine the steroid hormone effect on the physical performance of young athletes during an Olympic weightlifting competition.Methods:26 boys and 26 girls were monitored across 2 weightlifting competitions. Pre- and post-competition testosterone (T), cortisol (C) and dehydroepiandrosterone-sulfate (DHEA-s) were measured in blood, with pre-event free T (FT) and the free androgen index (FAI) calculated. Body mass (BM) and weightlifting performance were recorded.Results:The boys had a larger BM, superior performance with more T, FT and a higher FAI than girls (p < .01). Although C (32%) and DHEA-s (8%) levels were elevated across competition, no sex differences in hormone reactivity were seen. In boys, DHEA-s correlated with performance (r = .46), but not after controlling for BM (r = .14). For girls, T correlated with performance (r = -0.51) after BM was controlled.Conclusion:The sex differences that emerge during puberty were observable, whereby the boys were larger and stronger with a more anabolic profile than girls. Individual DHEA-s (boys) and T (girls) levels were related to performance, but BM appeared to be acting as a mediating (boys) or suppressing (girls) variable. This adds new insight regarding the hormonal contribution to competitive performance in young athletes.
Reliability of Heart Rate Variability in Children: Influence of Sex and Body Position During Data Collection
Authors: Silva Carla Cristiane , Bertollo Maurizio , Reichert Felipe Fossati , Boullosa Daniel Alexandre , Nakamura Fábio Yuzo 
Published: September 2016

Purpose:To examine which body position and indices present better reliability of heart rate variability (HRV) measures in children and to compare the HRV analyzed in different body positions between sexes.Method:Twenty eutrophic prepubertal children of each sex participated in the study. The RR intervals were recorded using a portable heart rate monitor twice a day for 7 min in the supine, sitting, and standing positions. The reproducibility was analyzed using the intraclass correlation coefficient (ICC; two way mixed) and within-subject coefficient of variation (CV).Two-way ANOVA with repeated measures was used to compare the sexes.Results:High levels of reproducibility were indicated by higher ICC in the root-mean-square difference of successive normal RR intervals (RMSSD: 0.93 and 0.94) and Poincaré plot of the short-term RR interval variability (SD1: 0.92 and 0.94) parameters for boys and girls, respectively, in the supine position. The ICCs were lower in the sitting and standing positions for all HRV indices. In addition, the girls presented significantly higher values than the boys for SDNN and absolute high frequency (HF; p < .05) in the supine position.Conclusions:The supine position is the most reproducible for the HRV indices in both sexes, especially the vagal related indices.
Effects of Combined Vigorous Interval Training Program and Diet on Body Composition, Physical Fitness, and Physical Self-Perceptions Among Obese Adolescent Boys and Girls
Authors: Rey Olivier , Vallier Jean-Marc , Nicol Caroline , Mercier Charles-Symphorien , Maïano Christophe 
Published: September 2016

Purpose:This study examined the effects of a five-week intervention combining vigorous interval training (VIT) with diet among twenty-four obese adolescents. Fourteen girls and ten boys (aged 14–15) schooled in a pediatric rehabilitation center participated. Methods:The VIT intensity was targeted and remained above 80% of maximal heart rate (HR) and over six kilocalories per minute. Pre- and postintervention measures were body composition (BMI, weight, body fat percentage), physical self-perceptions (PSP), physical fitness (6-min walking distance and work) and its associated physiological responses (HRpeak and blood lactate concentration). A series of two-way analyses of variance or covariance controlling for weight loss were used to examine the changes. Results:Significant improvements were found in body composition, physical fitness and PSP (endurance, activity level, sport competence, global physical self-concept and appearance). In addition, boys presented higher levels of perceived strength and global physical self-concept than girls. Finally, there was a significant increase in perceived endurance, sport competence, and global physical self-concept in girls only. Conclusion:This five-week VIT program combined with diet represents an effective means for improving body composition, physical fitness, and PSP in obese adolescents, the effects on PSP being larger among girls.