PET Index Research Articles

Baseline [18F]GTP1 tau PET imaging is associated with subsequent cognitive decline in Alzheimer\u2019s disease

BackgroundThe role and implementation of tau PET imaging for predicting subsequent cognitive decline in Alzheimer’s disease (AD) remains uncertain. This study was designed to evaluate the relationship between baseline [18F]GTP1 tau PET and subsequent longitudinal change across multiple cognitive measures over 18 months.MethodsOur analyses incorporated data from 67 participants, including cognitively normal controls (n = 10) and β-amyloid (Aβ)-positive individuals ([18F] florbetapir Aβ PET) with prodromal (n = 26), mild (n = 16), or moderate (n = 15) AD. Baseline measurements included cortical volume (MRI), tau burden ([18F]GTP1 tau PET), and cognitive assessments [Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR), 13-item version of the Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-Cog13), and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS)]. Cognitive assessments were repeated at 6-month intervals over an 18-month period. Associations between baseline [18F]GTP1 tau PET indices and longitudinal cognitive performance were assessed via univariate (Spearman correlations) and multivariate (linear mixed effects models) approaches. The utility of potential prognostic tau PET cut points was assessed with ROC curves.ResultsUnivariate analyses indicated that greater baseline [18F]GTP1 tau PET signal was associated with faster rates of subsequent decline on the MMSE, CDR, and ADAS-Cog13 across regions of interest (ROIs). In multivariate analyses adjusted for baseline age, cognitive performance, cortical volume, and Aβ PET SUVR, the prognostic performance of [18F]GTP1 SUVR was most robust in the whole cortical gray ROI. When AD participants were dichotomized into low versus high tau subgroups based on baseline [18F]GTP1 PET standardized uptake value ratios (SUVR) in the temporal (cutoff = 1.325) or whole cortical gray (cutoff = 1.245) ROIs, high tau subgroups demonstrated significantly more decline on the MMSE, CDR, and ADAS-Cog13.ConclusionsOur results suggest that [18F]GTP1 tau PET represents a prognostic biomarker in AD and are consistent with data from other tau PET tracers. Tau PET imaging may have utility for identifying AD patients at risk for more rapid cognitive decline and for stratification and/or enrichment of participant selection in AD clinical trials.Trial registrationClinicalTrials.gov NCT02640092. Registered on December 28, 2015

Temporal Analysis of Urban-Suburban PET, mPET and UTCI Indices in Belgrade (Serbia)

The analysis of the bioclimatic conditions is becoming increasingly relevant in climate interpretations for human needs, particularly in spatial planning, tourism, public health, sports events, bio-prognosis, etc. In this context, our study presents general temporal bioclimatic conditions in Belgrade, defined based on the PET, mPET and UTCI heat budget indices. Monthly, seasonal and annual indices were analyzed for urban and suburban weather stations based on 43 annual sets of meteorological data obtained by hourly observations at 7 h and 14 h CET. This study aims to present the distribution of PET, mPET and UTCI indices to show the pattern of each index in a mild climate location and to examine annual and seasonal differences of each index in the Belgrade urban center and suburban part of the city. The study results indicate higher biothermal stress in the urban area compared to the suburban zone and that the indices are congruent during the summer. At the same time, during the winter, they are more difficult to compare due to their peculiarities becoming more noticeable. The results obtained of all mean monthly and mean annual values of all three indices clearly indicate the difference that follows the definition of the urban heat island (UHI), particularly those from morning observation and winter season. The UTCI index shows the most significant monthly, seasonal and annual difference between urban and suburban areas for both observations. The annual difference of ΔUTCI7h amounts to 1.5 °C is the same as the annual difference of minimum temperatures (Δtmin). In contrast, the annual differences of ΔPET7h ΔmPET7h are °smaller (0.8 °C and 0.7 °C) and closer to the annual differences of maximum temperatures Δtmax amounted of 0.6 °C.

Biomimicry-Based Strategies for Urban Heat Island Mitigation: A Numerical Case Study under Tropical Climate.

In recent years, demographic growth has caused cities to expand their urban areas, increasing the risk of overheating, creating insurmountable microclimatic conditions within the urban area, which is why studies have been carried out on the urban heat island effect (UHI) and its mitigation. Therefore, this research aims to evaluate the cooling potential in the application of strategies based on biomimicry for the microclimate in a historical heritage city of Panama. For this, three case studies (base case, case 1, and case 2) of outdoor thermal comfort were evaluated, in which the Envi-met software was used to emulate and evaluate the thermal performance of these strategies during March (highest temperature month) and October (rainier month). The strategies used were extracted from the contrast of zebra skin, human skin, evaporative cooling, and ant skin. The results showed a reduction of 2.8 °C in the air temperature at 11:00, the radiant temperature decreased by 2.2 °C, and the PET index managed to reduce the thermal comfort indicator among its categories. The importance of thinking based on biomimicry in sustainable strategies is concluded; although significant changes were obtained, high risks of discomfort persist due to the layout and proximity of the building.

Effectiveness of Tree Pattern in Street Canyons on Thermal Conditions and Human Comfort. Assessment of an Urban Renewal Project in Historical District in Lodz (Poland)

The implementation of adaptation strategies has become an essential activity of spatial planning departments. Passive technologies related to the introduction of natural components in the form of vegetation are used, especially in urban development plans, to mitigate the effects of climate change and thus improve the quality of citizen life. Nature-Based Solutions are of particular importance in the areas of strict city centers, where historical building structures are subject to legal protection. In this study, the authors tested the influence of high greenery on the microclimatic conditions in the areas of typical street canyons (east–west and north–south orientations). Authors included the established greenery strategy by the City Planning Department. To estimate the impact of the assumed scenarios, a CFD tool was used—the ENVI-met application, which is commonly used in the field of urban microclimatology. Studies have shown that the introduction of 10% of green area contributed to a maximum air temperature reduction of 0.80 °C (17:00) in an east–west-oriented canyon, 0.49 °C (10:00) in a north–south canyon. The scenarios, assumed by the City Planning Department, related to the introduction of a greater amount of greenery turned out to be a less effective solution. The impact of greenery on the thermal comfort felt by humans was also determined. The reduction in the PET index was a maximum of 10.80 °C (14:00) in an east–west canyon; 6.66 °C (14:00) in a canyon area with a north–south orientation. This research might constitute the foundations to a re-evaluation of the urban development plans. The outcomes can lead to taking alternative direction of city layout transformations.

Evaluation of Biomimicry-based Strategies to Improve Exterior Environmental parameters: A numerical Study at Urban Scale in a tropical Climate

Due to population growth, cities have expanded their urban areas, causing increased temperatures and vegetative scarcity. Therefore, studies have been carried out on the urban heat island phenomenon, its effect on people’s thermal stress, and how to mitigate this problem. This research aims to evaluate the application of biomimetic strategies for improving exterior environmental conditions on an urban scale under a tropical climate through dynamic simulation. The case study takes place in the Casco Antiguo of Panama. Here, two cases were evaluated (base case and proposed case). The proposed case consists of strategies obtained from the application of the biomimetic design methodology. The ENVI-met software was used to evaluate both cases, where the external environmental parameters are compared between both cases for the critical months (March and October) at 15:00. Results showed that the air temperature reached an average reduction for March of 1.9 °C and 2 °C for October, the Tmr had an increase up to 0.6 °C in March and the PET index decreased 1.7 °C in March and in October 2 °C. Although significant changes were obtained, high levels of discomfort persist due to the narrowness and proximity of the buildings in this urban settlement.

Sky View Factor (SVF) assessment in a real-time system for thermal comfort conditions monitoring in the Moscow region

Comfort indices are used to assess the harm to human health caused by unfavorable thermal conditions. All calculated indices are based on both meteorological and physiological parameters. An algorithm is used which is based on a model RayMan for calculating two of the most common thermal indexes: PET and UTCI, which are based on a balance of human energy or models of human heat fluxes. The purpose of this research is to develop a real-time system of calculating comfort indices based on data of a web service for monitoring weather conditions in Moscow and the Moscow region. The technology is based on the use of specialized libraries of the Python language (pyautogui, pywinauto) to interact with the keys of a keyboard and a mouse, because it is necessary to write paths to files and make keystrokes in the model. The result is presented in a visually understandable form with a spatial distribution of the thermal stress in the form of points with signed index values at the locations of weather stations throughout Moscow and the surrounding areas. A test of sensitivity of the RayMan model to changes in a sky view factor (SVF) is also carried out. It is shown that the PET index is more sensitive to changes in SVF than UTCI. An assessment is made of the summer frequency of occurrence of cases with unfavorable levels of the thermal stress (taking into account SVF) at stations of the Roshydromet network in Moscow and the Moscow region. It is shown that during the controversial summer of 2019, the points where strong and extreme heat stresses most often occurred are located within the territories of Domodedovo and Sheremetyevo airports.

Citizen weather stations data for monitoring applications and urban climate research: an example of Moscow megacity

This study considers experience in use of crowdsourced meteorological observations from the world’s biggest network of citizen weather stations (CWSs), Netatmo, for urban climate research and applied monitoring services on the example of Moscow megacity. Crowdsourcing paradigm is an emerging alternative to the development of expensive urban meteorological networks. We have experimentally evaluated the uncertainties of the Netatmo temperature observations and regard them as being acceptable when the stations are shadowed from the sun. In order to filter out the misrepresentative observations, a quality-control algorithm has been developed. Within more than 1500 CWSs in the Moscow region, only about 25% meet this quality control, which is still one order of magnitude higher than the number of official Roshydromet weather stations in the study area. Such amount of data opens new opportunities for spatially-resolving urban climate studies and for applied services. As an example of the latter, we present a prototype of a web-mapping application for a near-real-time temperature monitoring system in Moscow. The application’s backend includes automatic services for downloading of observations from Netatmo and official Roshydromet networks, as well as for database maintaining. The processed data are visualized interactively in a web browser. The application is available on the Internet at http://carto.geogr.msu.ru/mosclim/. It will be further developed to include a real-time thermal comfort assessment based on the contemporary PET and UTCI biometeorological indices, a visualization of the interpolated fields, and other improvements.

The effect of kharkhona on outdoor thermal comfort in Hot and dry climate: A case study of Sistan Region in Iran

Few, if any, studies have researched the effects of vegetation, water and shading on outdoor thermal comfort in the hot and dry climate. This study identified and examined the effect of kharkhona as an architectural element of Sistan Region, which is often used in closed spaces, on outdoor thermal comfort in the hot and dry climate of Sistan during the summers of 2019 and 2020 with the aim of improving the unfavorable climatic conditions of the region via building on a technique devised by the residents of Sistan. To this end, a kharkhona was designed, built and evaluated in an open urban space. Physiological equivalent temperature index, which has been shown to be highly associated with the sensation of thermal comfort, was used as the indicator for evaluation of outdoor thermal condition. The findings showed that kharkhona can reduce the PET index by 9.34 °C in the space inside kharkhona compared to the environment outside the construct and moderate the “hot” and “very hot” heat sensation of the space outside kharkhona to “warm” and “slightly warm” in the inner space of the construct. Kharkhona can be used as a reference model for designing natural ventilation and is a viable strategy for modification of outdoor thermal comfort since it can provide better comfort conditions than vegetation.

خنک سازی محیطهای شهری و تأثیر آن بر تغییرات اقلیمی در محلات سنتی و سکونتگاههای غیررسمی از طریق آسایش حرارتی بیرونی (نمونه موردی محلات عاملی ، قلعه ساختمان و شهرک حجت شهر مشهد)

خنک سازی محیطهای شهری و تأثیر آن بر تغییرات اقلیمی در محلات سنتی و سکونتگاههای غیررسمی از طریق آسایش حرارتی بیرونی (نمونه موردی محلات عاملی ، قلعه ساختمان و شهرک حجت شهر مشهد)

A decision support tool for calculating effective shading in urban streets

In times of climate change a strong effort should be made to enhance thermal conditions within cities to create livable environments. Shading in urban open spaces has been recognized as an important parameter in modifying microclimatic conditions and enhancing thermal comfort particularly in hot regions. When designed appropriately, shading can mitigate the Urban Heat Island (UHI), enhance pedestrian thermal comfort and affect outdoor activities.A decision support tool (DST) was developed for evaluating the minimum shading coverage required, by trees or other shading devices, to improve thermal comfort in streets during the most critical hours of the day. The presented DST accounts for the density of tree-canopies or the albedo of various materials used for shading devices. To develop the index, a set of climatic simulations was run using the Green CTTC model and thermal comfort was determined by the PET index. Based on the simulations Open-space Shading Coefficients (OSC) were computed and used to develop an Open-space Shading Index (OSI). The city of Tel-Aviv, characterized by a hot-humid climate, was selected as a case study. Results demonstrate the viability of the index as a DST for assessing the extent of shading required to achieve thermal comfort in urban streets.

Climate comfort depending on different altitudes and land use in the urban areas in Kahramanmaras City

Climate comfort based caused by geographical conditions has influenced human activities, living standards, and even settlement forms from the early ages and continuous to so in our time. People have been coming up with various solutions in order to adapt to climatic conditions since the dawn of humanity. Despite the technological advancement that resulted in the manufacturing of climate and thermal control devices and equipment, the periodical change of settlements in certain areas is observed to this day. Kahramanmaras and the surrounding city serve as an example wherein climate comfort changes with time and location. The main objective of this research is to determine hourly climate comfort and the adaptation of people in and around city. Climate data were hourly organized, PET index was established to determine the climate comfort, and these indices were classified according to the psychology diagram equivalent to the temperature. Later, the climate comfort maps obtained spatially were superimposed on the city settlements. It has been determined that throughout the city planning, people moved and developed a different way of life due to the temporal-spatial variation of climate comfort. This movement has gathered pace due to the effect of summer heat waves which is a direct result of urban heat islands and climate change. It is necessary that this situation should be reflected in climate comfort-based planning.

Multiparametric positron emission tomography/magnetic resonance imaging in nasopharyngeal carcinoma: Correlations between magnetic resonance imaging functional parameters and 18F-fluorodeoxyglucose positron emission tomography imaging biomarkers and their predictive value for treatment failure.

Objectives:The clinical significance of positron emission tomography/magnetic resonance imaging (PET/MRI) functional parameters in nasopharyngealcarcinoma (NPC) remains unclear. The purpose of this prospective study was two-fold: (1) to investigate the associations between simultaneously acquired PET/MRI perfusion, diffusion, and glucose metabolism parameters in patients with NPC and (2) to analyze their predictive value with respect to treatment failure.Materials and Methods:We enrolled 85 patients with primary NPC who simultaneously underwent18F-fluorodeoxyglucose PET/CT and PET/MRI before definitive treatment. The following variables were determined: (1) functional parameters from the MRI component, including perfusion values (Ktrans,kep,ve, and initial area under the enhancement curve) and apparent diffusion coefficient (ADC) values, and (2) PET parameters, including metabolic tumor volume (MTV). The reciprocal interrelationships between these parameters and their correlations with treatment failure were examined.Results:We observed significant negative associations between Ktrans and ADC (r = −0.215, P = 0.049) as well as between ve and ADC (r = −0.22, P = 0.04). Correlations between PET and MRI functional parameters were not statistically significant. Treatment failures were observed in 21.2% of patients without distant metastases. Multivariate analysis identified ve as a significant independent predictor for treatment failure (P = 0.022), whereas MTV showed a borderline significance (P = 0.095). Patients in whom both ve and MTV values were increased had a significantly higher rate of treatment failure (62.5%) than those with either one (21.9%) or no (7.7%) increased parameter (P = 0.004).Conclusion:Correlation analyses revealed complex interrelationships among PET and MRI indices measured in patients with NPC. These parameters may have a complementary role in predicting treatment failure in this clinical setting.

The impact of green space structure on physiological equivalent temperature index in open space

Planting vegetation in urban areas can tilt the heat balance in favor of cooler temperatures. For this reason, studying the extension and intensity of the cooling effect of vegetation and the factors which can influence these two parameters is significant in open space design. In this regard, the purpose of the present study was to analyze the different thermal behaviors of green spaces at the micro scale and explain the reason of different extensions and intensities of the cooling effect in spaces which have vegetation. The region of Sistan (Zabol), situated east of Iran, was selected as the study area. Data analysis and study of the parameters affecting physiological equivalent temperature index indicated that the highest impact of green space on this index is related to air temperature and mean radiant temperature among all microclimatic parameters. It was revealed that in stations with vegetation, mean air temperature was lower by 1 °C, mean radiant temperature was lower by 6 °C and PET index was lower by 7 °C in comparison to stations without any vegetation. Analysis of the relation between PET and spatial variables which form the structure of green space, indicated that flooring type has a significant relation with physiological equivalent temperature.

Bandung Urban Dense Built Environment: Its Contribution on Microclimate and Living Quality

Urban village (kampong) becomes the city morphology phenomenon, its growth is organic and has no land use planning adequate. The tendency of increasing local temperatures in various metropolitan cities with high density has led to urban heat island. This article is a comprehensive study aimed at describes micro-climate aspects of the urban built environment. Detailed discussion on aspects morphology of the urban village will describe its implications for the formation of the microclimate that affects residential quality. Nine locations of kampong in Bandung with was then taken into samples, namely: Sukajadi, Tamansari, Sukapada, Cigondewah Kidul, Cigondewah Rahayu, Cicendo, Babakan Ciamis, and Cihaurgeulis. Detailed and specific discussion on aspects of mass and building shape, distance between buildings, height of buildings and availability green open space provides particular information of the influence of physical aspects of morphology on the microclimate, especially the most important to the average radiation temperature (Tmrt), others, such as air temperature (Ta), humidity (RH), and wind speed (v). The quality of the living environment as indicated by the PET index (Physiologically Equivalent Temperature). The final result shows Cigondewah Rahayu with 31.2∘C; 50.6%; 0,33m/s obtained PET = 35.9∘C with hot sensation. Based on the field measurement also find out that most of the nine kampongs are offering “warm” sensation living area, none of them have the “neutral,” “cool” or even “slightly cool” sensation.

Urban outdoor thermal perception in hot arid Beer Sheva, Israel: Methodological and gender aspects

In the 21st century, examination of thermal indices by subjective perception has become methodical. Over 120 studies have assessed human thermal perception by investigating in-situ thermal conditions as compared to subjective thermal perception. The majority were conducted in temperate and tropical climates whereas the arid and semi-arid zones have drawn little attention. The aims of this study were: (a) to evaluate human thermal perception in various outdoor urban spaces during the summer and winter in an arid city (b) to analyze the role of gender in thermal perception in an arid zone (c) to modify the human thermal perception scale for PET index for the city of Beer Sheva, Israel and (d) to examine current assessment methods for subjective human thermal sensation. The study was conducted in Beer Sheva city in hot and arid Southern Israel. Climatic measurements were carried out during the winter, spring and summer between 2009 and 2018 in different locations in the city. A questionnaire survey was conducted during the field measurements, with 2,994 valid responses. Based on the questionnaire, the PET full scale was modified for arid climate. The findings show that the modified PET scale of Beer Sheva shows adaptation to low rather than high temperatures. The modified Neutral PET ranges between 17°C and 26°C which is wider than in Mediterranean and hot, humid climates. Females are more sensitive to high temperatures and during the winter are more tolerant to low temperatures, probably due to their higher clothing ratio.

Diagnostic value of positron-emission tomography textural indices for malignancy of 18F-fluorodeoxyglucose-avid adrenal lesions.

PET Textural indices could have an add-on diagnostic value for diagnosis of malignancy in patients with FDG-avid adrenal lesions. Consecutive patients referred for a FDG-PET/CT to our nuclear medicine department from June 2012 to June 2017 were retrospectively screened. Inclusion criteria were: patients with a FDG-avid adrenal lesion (uptake≥liver background); malignant/benign lesion confirmed histologically or with follow-up imaging examination. Pheochromocytomas were not included in the analysis. For each adrenal lesion, 5 quantitative PET parameters (SUV<inf>max</inf>, MTV, TLG, TLR<inf>max</inf> and TLRmean<inf>)</inf> were calculated. Thirty-seven textural indices were extracted using LIFEx software®. Diagnostic performance to determine malignancy was assessed with a ROC analysis. Parameters with a significantly AUC>0.5 were selected and groups of highly correlated (r>0.8) parameters were created. A scoring system combining PET and textural indices was examined. PET textural indices were calculated for 53 lesions (37 malignant, 16 benign). Three PET metabolic parameters (SUV<inf>max</inf>, TLR<inf>max</inf>, TLRmean) and 13 textural indices had an AUC>0.5. Seven groups of highly correlated parameters (r>0.8) were extracted. For PET parameters, SUV<inf>max</inf> had the best AUC (0.89 95% CI [0.79-0.98]; cut-off=7.0). For textural indices, ZLNU had the best AUC (0.87 95% CI [0.78-0.96]; cut-off=34.7) and specificity of 100%. Three scores combining the best four textural indices alone (Contrast<inf>GLCM</inf>, LRHGE, SZE and ZLNU) or with one PET parameters (SUV<inf>max</inf>, TLR<inf>max</inf>) were developed but did not increase the diagnostic performance (AUC≤0.89). ZLNU was the best parameter to distinguish primary adrenal cancer from adrenal metastases in malignant lesions (P<0.001). Our study highlighted excellent diagnostic performance of several PET textural indices comparable to that of PET metabolic parameters. However, our results did not find any additional diagnostic value of textural indices when combined with metabolic parameters.

Identifying solar access effects on visitors' behavior in outdoor resting areas in a subtropical location: a case study in Japan Square in Curitiba, Brazil.

Changes in microclimate due to urban morphology tend to directly affect outdoor thermal comfort, thereby influencing people's behavior. In order to investigate that, this study analyzed preferences for specific resting areas within an urban square surrounded by high-rise buildings in a subtropical location. In order to understand behavioral adaptations as regards sunlight availability (direct or reflected) or shaded situations (partly, fully) in resting areas, the analysis was conducted according to an observational method during the four seasons of 2016. Two high-definition cameras with time-lapse function were positioned at vantage points facing distinct benches, shooting at intervals of 1.5min between scenes. Altogether, 86,561 scenes were analyzed. As a thermal comfort parameter, the outdoor thermal comfort index 'PET' (physiological equivalent temperature) was used, by post-processing meteorological data from the local meteorological station. The availability of situations (sun-lit, shaded-partly or fully, reflected sunlight) in each frame and per bench and the preference of visitors for such areas were considered in the analysis. During winter, there was a prevalence of shaded situations, mostly due to adjacent buildings. In summer, the most common condition was partly shaded by trees. The choice for a given resting condition was found to be closely related to PET index values and thermal comfort/stress classes and less so to seasonal changes.

A comparison of outdoor thermal comfort in historical and contemporary urban fabrics of Lar City

Comparative study of contemporary and historical urban fabrics will help urban designers to obtain strategies for climatic compatible design of cities. One of the main factors for evaluating thermal conditions in urban fabrics is measuring thermal comfort of inhabitants in public outdoor spaces. In this regard a neighborhood from the historical district of Lar city, using aerial photos of 1956 (before the devastations by the earthquake) is simulated and compared with another one in the new city of Lar.In this research, ENVI-met software is used to simulate both the historical and the new city districts. To validate the simulated models, meteorological data in the neighborhood (air temperature and relative humidity) were measured for a whole week; from 11th to 16th December of 2016, from 9 am to 15 pm, in new Lar city. For evaluating thermal conditions of these areas PET index is used. The results were compared considering urban geometry and green cover. It is observed that the inhabitants are less satisfied with thermal conditions in the historical urban fabric, which is the result of negligence to the urban public arena in this part of the city and a shortage of green cover in public passageways there.

Evaluation of 11C-Methionine PET and Anatomic MRI Associations in Diffuse Intrinsic Pontine Glioma.

The role of metabolic imaging in the diagnosis, treatment, and response assessment of diffuse intrinsic pontine glioma (DIPG) is poorly defined. We investigated the uptake of 11C-methionine in pediatric patients with newly diagnosed DIPG and evaluated the associations of 11C-methionine PET metrics with conventional MRI indices and survival outcomes. Methods: Twenty-two patients with newly diagnosed DIPG were prospectively enrolled on an institutional review board-approved investigational study of 11C-methionine PET. All patients underwent baseline 11C-methionine PET/CT, and initial treatment-response scans after chemotherapy or radiation therapy were obtained for 17 patients. Typical and atypical DIPGs were assessed clinically and radiographically and defined by multidisciplinary consensus. Three-dimensional regions of interest, reviewed by consensus between a nuclear medicine physician and a radiation oncologist, were delineated after coregistration of PET and MR images. Associations of 11C-methionine uptake intensity and uniformity with survival, along with associations between 11C-methionine uptake and conventional MRI tumor indices over time, were evaluated. 11C-methionine PET voxel values within regions of interest were assessed as threshold values across proportions of the study population, and 11C-methionine uptake at baseline was assessed relative to MRI-defined tumor progression. Results:11C-methionine uptake above that of uninvolved brain tissue was observed in 18 of 22 baseline scans (82%) and 15 of 17 initial response scans (88%). 11C-methionine avidity within MRI-defined tumor was limited in extent, with 11 of 18 positive baseline 11C-methionine PET scans (61%) showing less than 25% 11C-methionine-avid tumor. The increase in total tumor volume with 11C-methionine PET was relatively limited (17.2%; interquartile range, 6.53%-38.90%), as was the extent of 11C-methionine uptake beyond the MRI-defined tumor (2.2%; interquartile range, 0.55%-10.88%). Although baseline 11C-methionine PET intensity and uniformity metrics did not correlate with survival outcomes, initial 11C-methionine avidity overlapped with recurrent tumor in 100% of cases. A clinical diagnosis of atypical DIPG was associated with borderline significantly prolonged progression-free survival (P = 0.07), yet 11C-methionine PET indices at diagnosis did not differ significantly between atypical and typical DIPGs. Conclusion: Most newly diagnosed DIPGs are successfully visualized by 11C-methionine PET. Baseline 11C-methionine uptake delineates regions at increased risk for recurrence, yet intensity and uniformity metrics did not correlate with treatment outcomes in children with DIPG in this study.

Design of natural elements in open spaces of cities with a Mediterranean climate, conditions for comfort and urban ecology.

More than half the world's population lives in cities that were designed with a complete disregard for nature. Then, it is vital that nature should be present in these spaces to provide ecological support for urban areas. Natural elements that are in these spaces should be designed with people's comfort in mind. This research explores the application of the PET and UTCI biometeorological comfort indices in urban microspaces, where the general environmental parameters of the city are not valid and each space must be measured individually. The research looked into the influence of the design of natural elements on improving comfort. The results show that in the children's playing spaces, the absence of thermal comfort and considerable thermal stress were detected in summer. This effect is more easily seen in the PET values. The benefits to comfort of having double layers of vegetation in the gardens have also been shown. The micro-droplets of water from the jets in the fountains are carried by the breeze and modify the human-biometeorological conditions around the fountains and reduce thermal stress. This improvement needs an appropriate design of the fountains and an awareness of the breeze patterns in these spaces.