Bed Position Research Articles

Simultaneous isoquercitin and gallic acid production of <i>Aspergillus niger</i> on Triphala byproduct under solid state fermentation in packed-bed bioreactor

<abstract> <p>Triphala byproduct from hot-water extraction (TPB), which was a traditional process, was valorized by solid state fermentation in this research. Since the leftovers from the extraction contain high rutin and tannin contents, they were hydrolysable to isoquercitin and gallic acid, which were their monomers, respectively. <italic>Aspergillus niger</italic>, a producer of α-L-rhamnosidase and β-glucosidase, was cultured on the TPB to produce both isoquercitin and gallic acid, which were powerful antioxidants used in medical applications. The solid-state fermentation (SSF) was conducted in the three-layered packed-bed bioreactor aerated with humid air at different rates (0.1, 0.2 and 0.3 L/L/min or vvm). The highest isoquercitin and gallic acid production rates were found in the SSF, with 0.1 vvm at 1.14/h and 0.3 vvm at 3.12/h, respectively. The interaction of aeration rate and fermentation time significantly affected the fungal growth and the production of gallic acid, while the isoquercitin production was affected only by the fermentation time. Moreover, the differences of their production yields in different positions of bed along the height of bioreactor found to be useful to design the harvesting period of the fermentation products including isoquercitin or gallic acid or simultaneous isoquercitin and gallic acid. The results clearly showed that aeration, harvesting time, and position of the bioreactor were crucial in designing the process for isoquercitin, gallic acid, or both.</p> </abstract>

Quantitative and visual analyses of the effect of activity reduction on image metrics and quality in 18F-FDG PET/MRI in pediatric oncology.

: The aim of our study was to evaluate the effect of reduced injected tracer activities on the quantitative image metrics and the visual image quality in whole-body 18F-FDG PET/MRI with TOF capability in pediatric oncology. Seventy-seven PET/MRI examinations of 54 patients were analyzed (standard injected activity: 1.9 MBq/kg, standard PET scan duration: 5 min per bed position). Lower activity PET images (1.2 MBq/kg and 0.9 MBq/kg) were retrospectively simulated from the originally acquired list-mode data sets. Quantitative parameters were assessed by measuring the SUV metrics, signal-to-noise ratio (SNR), contrast-to-noise ratios (CNR), and textural features in each PET data set. PET images were also evaluated visually for image quality by using a scoring system. SNRs were found as significantly different among PET data sets (p < 0.001) and showed increasing image noise with decreasing activities. CNR values did not show significant differences among PET data sets. The mean relative percentage changes in SUV metrics were found to be lower in 1.2 MBq/kg data set compared to 0.9 MBq/kg data set. Lesion SUVmax, SUVmean, SULpeak, and textural features were significantly different in 0.9 MBq/kg data set compared to the original data set (p < 0.05 for all). However, SUV metrics and textural features did not show a significant difference between the original and 1.2 MBq/kg data sets. While, the mean visual scores in 0.9 MBq/kg data set were significantly different compared to the original data set (p < 0.001), there was no significant difference between the original and 1.2 MBq/kg data sets in terms of general image quality and image sharpness. Our analyses showed that the reduction of injected activity to 1.2 MBq/kg may be feasible in pediatric oncological PET/ MRI, with a smaller relative percentage change in quantitative parameters and with similar image quality to the original data set.

Novel Approach for Assessing Postinfarct Myocardial Injury and Inflammation Using Hybrid Somatostatin Receptor Positron Emission Tomography/Magnetic Resonance Imaging.

Novel Approach for Assessing Postinfarct Myocardial Injury and Inflammation Using Hybrid Somatostatin Receptor Positron Emission Tomography/Magnetic Resonance Imaging.

A finite element method for partially erodible bed evolution coupled with multiphase flows

This paper introduces a continuous finite element model for two phase flows coupled with evolving bedforms. The method extends the positive definite non-oscillatory finite element algorithm (NFEM) capabilities to predict sediment transport, multiphase flow, and evolution of the resulting interfaces limiting fluids, erodible sediment layers and non-erodible strata. Free surface hydrodynamics is simulated by the integration of the governing equations for incompressible multiphase flows, including the advection and reinitialization of a phase function to update the interface location. Sign preservation of the algorithm is essential both for fluid interface tracking procedure and for the landform tracking. In the first case, the property avoids unphysical overshoots along the free surface. In the second case, a positive definite thickness of the erodible layer of sediment is mandatory to account for interaction between evolving cohesionless sediment layers and rigid beds. To compute sediment layer thickness, the method incorporates a conservation law to balance evolution of the bed position with sediment mass flux, including a general template for saturated flux calculation. The framework permits the simulation from bed load dominant transport to saltation dominant transport. Fluid/terrain interface is explicitly captured by a surface tracking methodology whereby the mesh is adapted to the bedform. Numerical experiments explore several saturated sediment flow formulae for interactive evolution of dune/atmosphere system, as well as stringent dam-break type problems on channels with dry beds and partially and totally erodible beds.

Phantom and clinical evaluation of the effect of a new Bayesian penalized likelihood reconstruction algorithm (HYPER Iterative) on 68Ga-DOTA-NOC PET/CT image quality

BackgroundBayesian penalized likelihood (BPL) algorithm is an effective way to suppress noise in the process of positron emission tomography (PET) image reconstruction by incorporating a smooth penalty. The strength of the smooth penalty is controlled by the penalization factor. The aim was to investigate the impact of different penalization factors and acquisition times in a new BPL algorithm, HYPER Iterative, on the quality of 68Ga-DOTA-NOC PET/CT images. A phantom and 25 patients with neuroendocrine neoplasms who underwent 68Ga-DOTA-NOC PET/CT were included. The PET data were acquired in a list-mode with a digital PET/CT scanner and reconstructed by ordered subset expectation maximization (OSEM) and the HYPER Iterative algorithm with seven penalization factors between 0.03 and 0.5 for acquisitions of 2 and 3 min per bed position (m/b), both including time-of-flight and point of spread function recovery. The contrast recovery (CR), background variability (BV) and radioactivity concentration ratio (RCR) of the phantom; The SUVmean and coefficient of variation (CV) of the liver; and the SUVmax of the lesions were measured. Image quality was rated by two radiologists using a five-point Likert scale.ResultsThe CR, BV, and RCR decreased with increasing penalization factors for four “hot” spheres, and the HYPER Iterative 2 m/b groups with penalization factors of 0.07 to 0.2 had equivalent CR and superior BV performance compared to the OSEM 3 m/b group. The liver SUVmean values were approximately equal in all reconstruction groups (range 5.95–5.97), and the liver CVs of the HYPER Iterative 2 m/b and 3 m/b groups with the penalization factors of 0.1 to 0.2 were equivalent to those of the OSEM 3 m/b group (p = 0.113–0.711 and p = 0.079–0.287, respectively), while the lesion SUVmax significantly increased by 19–22% and 25%, respectively (all p < 0.001). The highest qualitative score was attained at a penalization factor of 0.2 for the HYPER Iterative 2 m/b group (3.20 ± 0.52) and 3 m/b group (3.70 ± 0.36); those scores were comparable to or greater than that of the OSEM 3 m/b group (3.09 ± 0.36, p = 0.388 and p < 0.001, respectively).ConclusionsThe HYPER Iterative algorithm with a penalization factor of 0.2 resulted in higher lesion contrast and lower image noise than OSEM for 68Ga-DOTA-NOC PET/CT, allowing the same image quality to be achieved with less injected radioactivity and a shorter acquisition time.

Application of the long axial field-of-view PET/CT with low-dose [18F]FDG in melanoma

AimThe recent introduction of long axial field-of-view (LAFOV) PET/CT scanners has yielded very promising results regarding image quality and sensitivity in oncological patients. We, herein, aim to determine an appropriate acquisition time range for the new long axial field of view Biograph Vision Quadra PET/CT (Siemens Healthcare) using low dose [18F]FDG activity in a group of melanoma patients.MethodologyForty-nine melanoma patients were enrolled in the study. All patients underwent total body PET/CT from the top of the head through the feet in two bed positions (field-of-view 106 cm) after i.v. injection of 2.0 MBq/kg [18F]FDG. The PET images of the first bed position (head to upper thigh; PET-10) were reconstructed and further split into 8-min (PET-8), 6-min (PET-6), 5-min (PET-5), 4-min (PET-4), and 2-min (PET-2) duration groups. Comparisons were performed between the different reconstructed scan times with regard to the visual evaluation of the PET/CT scans using the PET-10 images as reference and by calculating the 95%-CI for the differences between different time acquisitions. Moreover, objective evaluation of PET/CT image quality was performed based on SUV calculations of tumor lesions and background, leading to calculation of liver signal-to-noise ratio (SNR), and tumor-to-background ratio (TBR).ResultsA total of 60 scans were evaluated. Concerning visual analysis, 49/60 (81.7%) PET-10 scans were pathological, while the respective frequencies were 49/60 (81.7%) for PET-8 (95%-CI: − 0.0602–0.0602), 49/60 (81.7%) for PET-6 (95%-CI: − 0.0602–0.0602), 48/60 (80%) for PET-5 (95%-CI: − 0.0445–0.0886), 46/60 (76.7%) for PET-4 (95%-CI: − 0.0132–0.1370), and 45/60 (75%) for PET-2 (95%-CI: 0.0025–0.1593). In 18 PET-10 scans, the extent of metastatic involvement was very large, rendering the accurate calculation of [18F]FDG-avid tumor lesions very complicated. In the remaining 42 PET-10 scans, for which the exact calculation of tumor lesions was feasible, a total of 119 tumor lesions were counted, and the respective lesion detection rates for shorter acquisitions were as follows: 97.5% (116/119) for PET-8 (95%-CI: 0–1), 95.0% (113/119) for PET-6 (95%-CI: 0–1), 89.9% (107/119) for PET-5 (95%-CI: 0–2), 83.2% (99/119) for PET-4 (95%-CI: 1–2), and 73.9% (88/119) for PET-2 (95%-CI: 2–4). With regard to objective image quality evaluations, as a general trend, the reduction of acquisition time was associated with a decrease of liver SNR and a decrease of TBR, although in lesion-based analysis the change in TBR and tumor SUVmean values was non-significant up to 6 and 5 min acquisitions, respectively.ConclusionsIn melanoma, low-dose LAFOV PET/CT imaging is feasible and can reduce the total scan time from head to upper thigh up to 5 min providing comparable diagnostic data to standard lengths of acquisition. This may have significant implications for the diagnostic work-up of patients with melanoma, given the need for true whole-body imaging in this type of cancer.

In Vitro Assessment of Compounded Lurasidone Suspensions for Enteral Feeding Tubes.

Purpose: Extemporaneously compounded drug suspensions are often necessary for patients who are intubated or receiving nutrition through enteral feeding tubes. Lurasidone is a relatively new antipsychotic medication available only as oral tablets (Latuda®), and there is no data to support its use in this patient population as a compounded liquid formulation. This study was designed to assess the feasibility of preparing lurasidone suspensions from tablets and their compatibility with enteral feeding tubes. Methods: Representative nasogastric tubes were selected for this study, including polyurethane, polyvinylchloride, and silicone tubes with a range of 8 to 12 Fr (2.7-4.0 mm) in diameter and 35 to 55″ in length. Two strengths of lurasidone suspensions, 1 and 8 mg/mL, were prepared by the standard mortar-pestle method. Latuda® tablet 120 mg was used as the drug source, and a 1:1 mixture of Ora-Plus®:water was used as the suspension vehicle. The drug suspensions were delivered through the tubes mounted on a peg board to simulate patient position in a hospital bed. The ease of administration through the tubes was evaluated visually. The drug concentration before and after the tube delivery was analyzed by high performance liquid chromatography (HPLC). In addition, a 14-day stability study of the compounded suspensions was performed at room temperature to support the beyond-use dating. Results: Freshly prepared lurasidone suspensions, 1 and 8 mg/mL, met the potency and uniformity requirements. Both strengths of suspensions exhibited satisfactory flowability through all the tube types studied with no signs of clogging. The HPLC results confirmed that greater than 97% of drug concentration was retained after tube delivery. During the 14-day stability study, the suspensions retained greater than 93% of their original concentration. There was no significant change in pH or visual appearance. Conclusions: The study demonstrated a practical procedure to prepare 1 and 8 mg/mL lurasidone suspensions that are compatible with commonly used enteral feeding tube materials and dimensions. A beyond-use date of 14-day was established for the suspensions stored at room temperature.

Transition to Fast Whole-Body SPECT/CT Bone Imaging: An Assessment of Image Quality.

To investigate the impact of reduced SPECT acquisition time on reconstructed image quality for diagnostic purposes. Data from five patients referred for a routine bone SPECT/CT using the standard multi-bed SPECT/CT protocol were reviewed. The acquisition time was 900 s using gating technique; SPECT date was resampled into reduced data sets of 480 s, 450 s, 360 s and 180 s acquisition duration per bed position. Each acquisition time was reconstructed using a fixed number of subsets (8 subsets) and 4, 8, 12, and 16 iterations, followed by a post-reconstruction 3D Gaussian filter of 8 mm FWHM. Two Nuclear Medicine physicians analysed all images independently to score image quality, noise and diagnostic confidence based on a pre-defined 4-point scale. Our result showed that the most frequently selected categories for 480 s and 450 s images were good image quality, average noise and fair confidence, particularly at lower iteration numbers 4 and 8. For the shortened acquisition time of 360 s and 180 s, statistical significance was observed in most reconstructed images compared with 900 s. The SPECT/CT can significantly shorten the acquisition time with maintained image quality, noise and diagnostic confidence. Therefore, acquiring data over 480 s and 450 s is feasible for WB-SPECT/CT bone scans to provide an optimal balance between acquisition time and image quality.

Assessment of dynamic cerebral autoregulation in near-infrared spectroscopy using short channels: A feasibility study in acute ischemic stroke patients.

In acute ischemic stroke, progressive impairment of cerebral autoregulation (CA) is frequent and associated with unfavorable outcomes. Easy assessment of cerebral blood flow and CA in stroke units bedside tools like near-infrared spectroscopy (NIRS) might improve early detection of CA deterioration. This study aimed to assess dynamic CA with multichannel CW-NIRS in acute ischemic stroke (AIS) patients compared to agematched healthy controls. CA reaction was amplified by changes in head of bed position. Long- and short channels were used to monitor systemic artery pressure- and intracranial oscillations simultaneously. Gain and phase shift in spontaneous low- and very low-frequency oscillations (LFO, VLFO) of blood pressure were assessed. A total of 54 participants, 27 with AIS and 27 age-matched controls were included. Gain was significantly lower in the AIS group in the LFO range (i) when the upper body was steadily elevated to 30. and (ii) after its abrupt elevation to 30°. No other differences were found between groups. This study demonstrates the feasibility of NIRS short channels to measure CA in AIS patients in one single instrument. A lower gain in AIS might indicate decreased CA activity in this pilot study, but further studies investigating the role of NIRS short channels in AIS are needed.

Modification of [18F]-FDG PET/CT imaging protocols in obese oncology patients: A nationwide survey

IntroductionThe use of medical imaging for diagnosis, staging and follow-up in Oncology context is incredibly important, being the use of [18F]-FDG PET/CT particularly advantageous in specific contexts like the case of obese patients. However, imaging the latter can be challenging sometimes, since their own body size may affect overall image quality and adds technical difficulties for the operator(s) performing the examination. MethodsThis research project was developed with the aim of analysing the current personal practices of Portuguese Nuclear Medicine Technologists (NMTs) in the adaptation of 18F-FDG PET/CT oncological protocols for obese patients and comparing the results with parameters referenced in literature. A non-experimental research study was conducted using a survey delivered online to NMTs through social media platforms (Facebook® and LinkedIn®) and by sending the link directly to contacts within the research team professional and personal networks. ResultsAnswers from a total of 26 participants were obtained, with 88.5% of participants admitting modifying technical protocols in examinations for obese patients. Changes in PET protocols included an increase in the administered activity (60.9%), an increase in scan time per individual bed position (69.6%) and the use of Time-of-Flight (TOF) technology whenever available. Protocol changes in CT included increasing the mA (82.6%), raising the KVp (47.8%), the application of iterative reconstruction (69.6%) and the use of automatic exposure control (AEC) (52.2%). The remaining parameters (pitch, algorithm, slice thickness, display FOV, gantry rotation time and energy acceptance window) were claimed not to be modified by around 90% of professionals. ConclusionPortuguese NMTs tend to change the [18F]-FDG PET/CT protocols for obese patients. However, while some of the parameters appear to be contradictory or redundant, others require further optimisation, especially in the CT component. Implications for practiceEfforts should be made to optimize acquisition protocols used in [18F]-FDG PET/CT scans for obese patients.

Variations in sacral oedema levels over continuous 60-degree head of bed elevation positioning in healthy adults: An observational study

BackgroundSubepidermal moisture (SEM) scanning is a novel technology that measures changes in localised oedema. Accumulation of subepidermal oedema is associated with early tissue damage that may lead to a pressure injury. AimThe primary study objective was to observe the variations in sacral subepidermal oedema levels over a continuous period of 60-degree head of bed elevation positioning. MethodsHealthy adult participants were recruited in this prospective observational study. Participants were positioned at 60-degree head of bed elevation for 120 min and sacral SEM measurements were collected at baseline and in 20 min increments. ResultsA total of 20 participants with a mean age of 39.3 years (SD = 14.7) were recruited. The mean SEM delta value increased 6.3% from 0.46 SEM delta at baseline to 0.49 SEM delta after 120 min, however these differences are not statistically significant (p = .21). There were also no significant findings between SEM delta variations and demographic factors. ConclusionIn a sample of healthy individuals, 120 min of continuous loading with a 60-degree head of bed elevation did not lead to a significant change in sacral subepidermal oedema levels. Further research on the response of healthy adult tissue under external forces associated with different angles of head of bed positioning may further contribute to our understanding pressure injury prevention.

Optimization of Adaptive Threshold in Tumor Segmentation Based on I-124 PET/CT NEMA Phantom Study

Numerous methods have been introduced to segment the thyroid tumors in iodine-124 (124I) Positron Emission Tomography/Computer Tomography (PET/CT) imaging. An adaptive threshold-based is preferable to a manual and fixed threshold-based approach for forecasting accurate and precise tumor volume in real-patient studies, as it was reported to be more resistant to noise and resolution. Manual segmentation was reported to be time-consuming, subjective, subject to inter- and intra-observer variability and prone to segmentation errors [1]. This study aimed to determine the optimal adaptive threshold for thyroid tumor segmentation in 124I PET/CT imaging.&#x0D; &#x0D; The objective of this study was firstly to determine the segmented volume using the standardized uptake value threshold method. Secondly, to compare the adaptive threshold and recovery coefficient (RC) value between the time of flight (TOF) and non-time of flight (non-TOF) PET/CT reconstructions in 124I phantom studies. Finally, to determine the accuracy and RC for 124I PET/CT studies. This study was done by placing NEMA 2012/IEC 2008 PET IQ Phantom and filled with 1 kBq/ml and 20 kBq/ml in its background and sphere each to model tumor background ratio (TBR) 20:1 of 124I PET/CT imaging. The phantom was scanned using TOF and non-TOF PET at 3, 4 and 5 minutes per bed position and reconstructed using 600, 1200 and 2000 beta penalization factors. Image registration, contouring and segmentation were performed using MIM Encore Software. A set of different adaptive thresholds (Tadaptive: 10%-50%) was applied to each sphere in the TBR image of the phantom using the tri-dimensional automatic segmentation tool. The optimal Tadaptive for each of the parameter assessed was defined based on the lowest goodness value calculated. The RC was calculated using mean value and known activity. Finally, the RC against the percentage of maximum was plotted to analyse the descending order of beta penalization factors for time per bed position.&#x0D; &#x0D; Figure 1 shows the image of 124I contoured VOIs on the spheres. The results showed that segmented volumes were not affected by the time per bed position in 124I PET/CT imaging. Table 1 shows the descending order beta penalization factors for time per bed position. Beta penalization factors of 600 to 2000 resulted in either underestimation or overestimation of the measured volume. Comparing TOF to non-TOF PET/CT 124I imaging, consistent and reproducible data were observed for the TOF PET for the three beta penalization factors. Tadaptive of 28.0% consistently gave the lowest goodness value shown by the closest R2 value to one, thus can produce lowest error if it is being used to reconstruct images.&#x0D; As a conclusion, 28% Tadaptive is suggested as the optimal threshold for 124I TOF PET/CT imaging due to consistent data obtained for all beta penalization factors assessed in this study. The inconsistent data obtained by non-TOF PET thus requires further optimization.

Compton and proximity imaging of 225Ac in vivo with a CZT gamma camera: a proof of principle with simulations.

In vivo imaging of 225Ac is a major challenge in the development of targeted alpha therapy radiopharmaceuticals due to the extremely low injected doses. In this paper, we present the design of a multi-modality gamma camera that integrates both proximity and Compton imaging in order to achieve the demanding sensitivities required to image 225Ac with good image quality. We consider a dual-head camera, each of the heads consisting of two planar cadmium zinc telluride detectors acting as scatterer and absorber for Compton imaging, and with the scatterer practically in contact with the subject to allow for proximity imaging. We optimize the detector's design and characterize the detector's performance using Monte Carlo simulations. We show that Compton imaging can resolve features of up to 1.5 mm for hot rod phantoms with an activity of 1 μCi, and can reconstruct 3D images of a mouse injected with 0.5 μCi after a 15 minutes exposure and with a single bed position, for both 221Fr and 213Bi. Proximity imaging is able to resolve two 1 mm-radius sources of less than 0.1 μCi separated by 1 cm and at 1 mm from the detector, as well as it can provide planar images of 221Fr and 213Bi biodistributions of the mouse phantom in 5 minutes.

Role of Head Position in Stroke Outcome: An Observational Study from Tertiary Care Hospital in Pakistan

Background and Aim: Acute ischemic stroke patients mainly rely on cerebral blood flow (CBF) to sustain penumbral tissue perfusion in turn depend on arterial blood pressure in affected cerebral autoregulation. Head positioning either sitting-up or lying flat allows gravitational force to enhance leptomeningeal circulation and collateral blood flow. The present study aimed to determine the role of head position in acute ischemic stroke patients. Methodology: This prospective observational study was conducted on 500 stroke patients in the Department of Neurology and Medical department of Fauji Foundation Hospital, Rawalpindi from January 2020 to December 2021. Patients with acute ischemic stroke receive care in either a lying flat on bed or sitting-up position with elevated head position at 30 to 45 degrees. The designated position was established shortly after hospital admission and was held for 24 hours. Outcomes such as pneumonia, aspiration pneumonia, and increased hospital stay, disability, and mortality were associated with flat head position and elevated head position. Modified Rankine scale (0-6) was used for assessing the degree of disability as a primary outcome in three months. Rankine scale higher score indicates the greater disability and maximum score 6 indicate mortality. Results: The average time from initiation of assigned position and onset of ischemic stroke symptoms was 14 hours (IQR 5-35). Patients in the sitting position group (93%, p&lt;0.001) were more likely than the lying-flat group (82%, p&lt;0.001) in maintaining their position for 24 hours. Based on a modified Rankine scale, both lying flat and sitting-up position groups had no significant differences in a proportional-odds model in terms of 90-days disability outcomes distribution. The mortality rate in lying flat and sitting-up position was 6.8% and 6.9% (p=0.79). Also, both groups had no significant differences in terms of severe outcomes including pneumonia. Conclusion: The present study found that disability outcomes in acute stroke patients were similar irrespective of their position either flat or sitting position with head elevated at 30 to 45 degree for 24 hours. The prevalence of AIS was 95.6%. Keywords: Head position, Acute ischemic stroke, Outcomes

Human biodistribution and radiation dosimetry of the demyelination tracer [18F]3F4AP

Purpose[18F]3F4AP is a novel PET radiotracer that targets voltage-gated potassium (K+) channels and has shown promise for imaging demyelinated lesions in animal models of neurological diseases. This study aimed to evaluate the biodistribution, safety, and radiation dosimetry of [18F]3F4AP in healthy human volunteers.MethodsFour healthy volunteers (2 females) underwent a 4-h dynamic PET scan from the cranial vertex to mid-thigh using multiple bed positions after administration of 368 ± 17.9 MBq (9.94 ± 0.48 mCi) of [18F]3F4AP. Volumes of interest for relevant organs were manually drawn guided by the CT, and PET images and time-activity curves (TACs) were extracted. Radiation dosimetry was estimated from the integrated TACs using OLINDA software. Safety assessments included measuring vital signs immediately before and after the scan, monitoring for adverse events, and obtaining a comprehensive metabolic panel and electrocardiogram within 30 days before and after the scan.Results[18F]3F4AP distributed throughout the body with the highest levels of activity in the kidneys, urinary bladder, stomach, liver, spleen, and brain and with low accumulation in muscle and fat. The tracer cleared quickly from circulation and from most organs. The clearance of the tracer was noticeably faster than previously reported in nonhuman primates (NHPs). The average effective dose (ED) across all subjects was 12.1 ± 2.2 μSv/MBq, which is lower than the estimated ED from the NHP studies (21.6 ± 0.6 μSv/MBq) as well as the ED of other fluorine-18 radiotracers such as [18F]FDG (~ 20 μSv/MBq). No differences in ED between males and females were observed. No substantial changes in safety assessments or adverse events were recorded.ConclusionThe biodistribution and radiation dosimetry of [18F]3F4AP in humans are reported for the first time. The average total ED across four subjects was lower than most 18F-labeled PET tracers. The tracer and study procedures were well tolerated, and no adverse events occurred.

Patient mobilisation in the intensive care unit and evaluation of a multifaceted intervention including Facebook groups: A quasi-experimental study

AimsTo describe prevalence and time to mobilisation in intensive care unit patients defined as a minimum sitting in an upright position in bed, and evaluate the impact of a multifaceted quality improvement campaign on likelihood of patients being mobilised. Research methodology/designQuality improvement project using a quasi-experimental study design, comparing patient cohorts before (Before) and after (Intervention) a campaign including educational sessions, audit and feedback of intensive care unit quality indicators via closed Facebook-groups and e-mail and local opinion leaders. Secondary analysis of mobilisation data from adult intensive care patient stays extracted from electronical medical charts. Likelihood of being mobilised was analysed with Multivariate Cox-regression model and reported as Sub-hazard Ratio (SHR). SettingFour intensive care units in a university hospital. Main outcome measuresPrevalence and time to first documented mobilisation, defined as at least “sitting in bed” during the intensive care unit stay. ResultsOverall, 929 patients were analysed, of whom 710 (76 %) were mobilised; 73 % (356/ 489) in Before vs 81 % (354/ 440) in Intervention (p = 0.007). Median time to mobilisation was 69.9 (IQR: 30.0, 149.8) hours; 71.7 (33.9, 157.9) in Before and 66.0 (27.1, 140.3) in Intervention (p = 0.104). Higher SAPS II-scores were associated with lower likelihood (SHR 0.98, 95 % CI 0.97–0.99), whereas admissions due to gastroenterological failure (SHR 2.1, 95 % CI 1.4–3.0), neurological failure (SHR 1.5, 95 % CI 1.0–2.2) and other causes (intoxication, postoperative care, haematological-, and kidney failure) (SHR 1.7, 95 % CI 1.13–2.6) were associated with higher likelihood of mobilisation vs respiratory failure. ConclusionA quality improvement campaign including use of Facebook groups is feasible and may improve mobilisation in intensive care unit patients. Most patients were mobilised within 72 hours following intensive care unit admission, and SAPS II scores and causes for intensive care unit admission were both associated with likelihood of being mobilised.

Analysis on Damage and Mechanical Properties of Ballastless Track in a Tunnel after a Fire.

In order to explore the damage and mechanical properties of ballastless track after a fire, the uniaxial compressive strength, shear strength, peak strain, and elastic modulus changes due to temperature were obtained through uniaxial compressive and shear tests of concrete after exposure to high temperatures. The test results showed that with increases in temperature, the uniaxial compressive strength, shear strength, and elastic modulus of concrete all presented a decreasing trend, while the peak strain had an increasing trend. Then, based on the classical damage theory model and the strength probability distribution function of concrete micro-units, the high-temperature damage constitutive equation for concrete was established, and the compressive stress–strain curve of concrete after exposure to high temperature was reproduced. Finally, using the CFD numerical simulation software, the temperature field of a ballastless track structure in a tunnel during a fire was obtained, and the temperatures at different positions of ballastless track bed were acquired. Combined with the high-temperature damage constitutive equation for concrete deduced from tests and theoretical analysis, the strength and damage values of the ballastless track bed at different positions after a tunnel fire were obtained.

Simulated Reduced-Count Whole-Body FDG PET: Evaluation in Children and Young Adults Imaged on a Digital PET Scanner.

BACKGROUND. Digital PET scanners with increased sensitivity may allow shorter scan acquisition times or reductions in administered radiopharmaceutical activities. OBJECTIVE. The purpose of this study was to evaluate in children and young adults the impact of shorter simulated acquisition times on the quality of whole-body FDG PET images obtained using a digital PET/CT system. METHODS. This retrospective study included 27 children and young adults (nine male and 18 female patients) who underwent clinically indicated whole-body FDG PET/CT examinations performed using a 25-cm axial FOV PET/CT system at 90 s per bed position (expressed hereafter as seconds per bed). Raw list-mode data were reprocessed to simulate acquisition times of 60, 55, 50, 45, 40, and 30 s/bed. Three radiologists independently reviewed reconstructed images and assigned Likert scores for lesion conspicuity, normal structure conspicuity, image quality, and image noise. A separate observer recorded the SUVmax, SUVmean, and SD of the SUV (SUVSD) for liver, thigh, and the most FDG-avid lesion. The SUVSD/SUVmean (the SUVSD divided by the SUVmean) was calculated as a surrogate of image noise. ANOVA, the Friedman test, and the Dunn test were used to compare qualitative measures (combining reader scores) and SUV measurements. RESULTS. The mean patient age was 10.8 ± 8.3 (SD) years, mean BMI was 18.7 ± 2.9, and mean administered FDG activity was 4.44 ± 0.37 MBq/kg (0.12 ± 0.01 mCi/kg). No qualitative measure showed a significant difference versus 90 s/bed for the simulated acquisition at 60 s/bed (all p > .05). Significant differences (all p < .05) versus 90 s/bed were observed for lesion conspicuity at at most 40 s/bed, conspicuity of normal structures and overall image quality at at most 45 s/bed, and image noise at at most 55 s/bed. SUVmean was not significantly different from 90 s/bed for any site for any reduced-count simulation (all p > .05). SUVSD/SUVmean and SUVmax showed gradual increases with decreasing acquisition times and were significantly different from 90 s/bed only for liver at 60 s/bed (for SUVmax: 1.00 ± 0.00 vs 1.05 ± 0.03, p = .02; for SUVSD/SUVmean: 0.09 ± 0.02 vs 0.11 ± 0.02, p = .04). CONCLUSION. Favorable findings for the simulated acquisition at 60 s/bed suggest that, in children and young adults who undergo imaging performed using a 25-cm FOV digital PET scanner, acquisition time or administered FDG activity may be decreased by approximately 33% from the clinical standard without significantly impacting image quality. CLINICAL IMPACT. A 25-cm axial FOV digital scanner may allow FDG PET/CT examinations to be performed with reduced radiation exposure or faster scan acquisition times.

Measuring Repositioning in Home Care for Pressure Injury Prevention and Management.

Despite the widespread agreement on the need for the regular repositioning of at-risk individuals for pressure injury prevention and management, adherence to repositioning schedules remains poor in the clinical environment. The situation in the home environment is likely even worse. Our team has developed a non-contact system that can determine an individual’s position in bed (left-side lying, supine, or right-side lying) using data from a set of inexpensive load cells placed under the bed. This system was able to detect whether healthy participants were left-side lying, supine, or right-side lying with 94.2% accuracy in the lab environment. The objective of the present work was to deploy and test our system in the home environment for use with individuals who were sleeping in their own beds. Our system was able to detect the position of our nine participants with an F1 score of 0.982. Future work will include improving generalizability by training our classifier on more participants as well as using this system to evaluate adherence to two-hour repositioning schedules for pressure injury prevention or management. We plan to deploy this technology as part of a prompting system to alert a caregiver when a patient requires repositioning.

Biodistribution and dosimetry of the GluN2B-specific NMDA receptor PET radioligand (R)-[11C]Me-NB1

BackgroundThe NMDA receptor (NMDAR) plays a key role in the central nervous system, e.g., for synaptic transmission. While synaptic NMDARs are thought to have protective characteristics, activation of extrasynaptic NMDARs might trigger excitotoxic processes linked to neuropsychiatric disorders. Since extrasynaptic NMDARs are typically GluN2B-enriched, the subunit is an interesting target for drug development and treatment monitoring. Recently, the novel GluN2B-specific PET radioligand (R)-[11C]Me-NB1 was investigated in rodents and for the first time successfully translated to humans. To assess whether (R)-[11C]Me-NB1 is a valuable radioligand for (repeated) clinical applications, we evaluated its safety, biodistribution and dosimetry.MethodsFour healthy subjects (two females, two males) underwent one whole-body PET/MR measurement lasting for more than 120 min. The GluN2B-specific radioligand (R)-[11C]Me-NB1 was administered simultaneously with the PET start. Subjects were measured in nine passes and six bed positions from head to mid-thigh. Regions of interest was anatomically defined for the brain, thyroid, lungs, heart wall, spleen, stomach contents, pancreas, liver, kidneys, bone marrow and urinary bladder contents, using both PET and MR images. Time-integrated activity coefficients were estimated to calculate organ equivalent dose coefficients and the effective dose coefficient. Additionally, standardized uptake values (SUV) were computed to visualize the biodistribution.ResultsAdministration of the radioligand was safe without adverse events. The organs with the highest uptake were the urinary bladder, spleen and pancreas. Organ equivalent dose coefficients were higher in female in almost all organs, except for the urinary bladder of male. The effective dose coefficient was 6.0 µSv/MBq.ConclusionThe GluN2B-specific radioligand (R)-[11C]Me-NB1 was well-tolerated without reported side effects. Effective dose was estimated to 1.8 mSv when using 300 MBq of presented radioligand. The critical organ was the urinary bladder. Due to the low effective dose coefficient of this radioligand, longitudinal studies for drug development and treatment monitoring of neuropsychiatric disorders including neurodegenerative diseases are possible.Trial registration Registered on 11th of June 2019 at https://www.basg.gv.at (EudraCT: 2018-002933-39).