[Mental Health Stigma: An Influencing Factor in Healthcare Utilization by Veterans of the German Armed Forces]. / "Treffer im Kopf" ­ Stigma psychischer Erkrankungen als Einflussfaktor auf die Inanspruchnahme von Hilfsangeboten durch VeteranInnen der Bundeswehr.

THEORETICAL BACKGROUND AND OBJECTIVE OF THE STUDY: Mental illness stigma is a barrier to healthcare utilization. This study is the first to research the connection between mental illness stigma and the use of healthcare by veterans of the German Armed Forces. An overview of perceived stigma components in this sample is provided that should help understand how these factors influence healthcare utilization. METHODS: 43 interviews with veterans of the German Armed Forces were conducted. The resulting data were analyzed in several coding steps. It was investigated whether the stigma experience of veterans of the German Armed Forces could be well illustrated by the theory-based stigmatization model of Link and Phelan. A set of hypotheses on stigma and healthcare utilization based on the data were developed. RESULTS: All stigma components according to the model of Link and Phelan were found in the sample. Internalized stigma, perceived public stigmatization, vocational disadvantage and social exclusion as well as feared misunderstanding of the military past in the civilian sector were reported as main stigma-relevant barriers to the use of healthcare. CONCLUSIONS: Recommendations for interventions are given to decrease mental illness stigma in this specific group of former soldiers.

Mapping amorphous calcium phosphate transformation into crystalline mineral from the cell to the bone in zebrafish fin rays.

The continuously forming fin bony rays of zebrafish represent a simple bone model system in which mineralization is temporally and spatially resolved. The mineralized collagen fibrils of the fin bones are identical in structure to those found in all known bone materials. We study the continuous mineralization process within the tissue by using synchrotron microbeam x-ray diffraction and small-angle scattering, combined with cryo-scanning electron microscopy. The former provides information on the mineral phase and the mineral particles size and shape, whereas the latter allows high-resolution imaging of native hydrated tissues. The integration of the two techniques demonstrates that new mineral is delivered and deposited as packages of amorphous calcium phosphate nanospheres, which transform into platelets of crystalline apatite within the collagen matrix.

Plant cystoliths: a complex functional biocomposite of four distinct silica and amorphous calcium carbonate phases.

Plant cystoliths are mineralized objects that are formed by specialized cells in the leaves of certain plants. The main mineral component of cystoliths by volume is amorphous calcium carbonate (ACC) and the minor component is silica. We show that the silica stalk is formed first and is essential for ACC formation. Furthermore, the cystolith is shown to be composed of four distinct mineral phases with different chemical properties: an almost pure silica phase grades into a Mg-rich silica phase. This Mg-rich silica is overlaid by a relatively stable ACC phase. A bulky and less stable ACC phase encapsulates the first ACC phase. This architecture poses interesting questions about the role of Mg in the silica phase and suggests a strategy for ACC stabilization that takes advantage of a precise regulation of the mineral-growth microenvironment.

Psychosomatically Oriented Diagnostics and Therapy for Fertility Disorders. Guideline of the DGPFG (S2k-Level, AWMF Registry Number 016/003, December 2019).

Aim The purpose of this official guideline published and coordinated by the German Society for Psychosomatic Gynecology and Obstetrics [Deutsche Gesellschaft für Psychosomatische Frauenheilkunde und Geburtshilfe (DGPFG)] is to provide a consensus-based overview of psychosomatically oriented diagnostic procedures and treatments for fertility disorders by evaluating the relevant literature. Method This S2k guideline was developed using a structured consensus process which included representative members of various professions; the guideline was commissioned by the DGPFG and is based on the 2014 version of the guideline. Recommendations The guideline provides recommendations on psychosomatically oriented diagnostic procedures and treatments for fertility disorders.

Fighter, Corpsman, Partisan an Attempt to Typify Former Soldiers Based on their Coping and Defense Mechanisms.

This work strives to develop a typological classification of the use of conscious and unconscious defense and coping mechanisms based on methodically and structurally collected data from a qualitative survey of 43 former soldiers in Germany. Seven coping and defense types were identified: the Fighter, the Comrade, the Corpsman, the Strategist, the Partisan, the Self-Protector and the Infantryman. The types identified differed with regard to the accumulation, combination, and use of their conscious and unconscious defense and coping mechanisms in the superordinate areas of behaviour, relationships, emotions, reflexivity and time focus. The typological classification could offer psychotherapeutic interventions tailored to individuals and their defense and coping mechanisms, which could lead to improved therapy use and compliance.

Augmented Whole-Body Scanning via Magnifying PET.

A novel technique, called augmented whole-body scanning via magnifying PET (AWSM-PET), that improves the sensitivity and lesion detectability of a PET scanner for whole-body imaging is proposed and evaluated. A Siemens Biograph Vision PET/CT scanner equipped with one or two high-resolution panel-detectors was simulated to study the effectiveness of AWSM-PET technology. The detector panels are located immediately outside the scanner's axial field-of-view (FOV). A detector panel contains 2 ×8 detector modules each consisting of 32 ×64 LSO crystals ( 1.0 ×1.0 ×10.0 mm3 each). A 22Na point source was stepped across the scanner's FOV axially to measure sensitivity profiles at different locations. An elliptical torso phantom containing 7×9 spherical lesions was imaged at different axial locations to mimic a multi-bed-position whole-body imaging protocol. Receiver operating characteristic (ROC) curves were analyzed to evaluate the improvement in lesion detectability by the AWSM-PET technology. Experimental validation was conducted using an existing flat-panel detector integrated with a Siemens Biograph 40 PET/CT scanner to image a torso phantom containing spherical lesions with diameters ranging from 3.3 to 11.4 mm. The contrast-recovery-coefficient (CRC) of the lesions was evaluated for the scanner with or without the AWSM-PET technology. Monte Carlo simulation shows 36%-42% improvement in system sensitivity by a dual-panel AWSM-PET device. The area under the ROC curve is 0.962 by a native scanner for the detection of 4 mm diameter lesions with 5:1 tumor-to-background activity concentration. It was improved to 0.977 and 0.991 with a single- and dual-panel AWSM-PET system, respectively. Experimental studies showed that the average CRC of 3.3 mm and 4.3 mm diameter tumors were improved from 2.8% and 4.2% to 7.9% and 11.0%, respectively, by a single-panel AWSM-PET device. With a high-sensitivity dual-panel device, the corresponding CRC can be further improved to 11.0% and 15.9%, respectively. The principle of the AWSM-PET technology has been developed and validated. Enhanced system sensitivity, CRC and tumor detectability were demonstrated by Monte Carlo simulations and imaging experiments. This technology may offer a cost-effective path to realize high-resolution whole-body PET imaging clinically.

A second-generation virtual-pinhole PET device for enhancing contrast recovery and improving lesion detectability of a whole-body PET/CT scanner.

PURPOSE: We have developed a second-generation virtual-pinhole (VP) positron emission tomography (PET) device that can position a flat-panel PET detector around a patient's body using a robotic arm to enhance the contrast recovery coefficient (CRC) and detectability of lesions in any region-of-interest using a whole-body PET/computed tomography (CT) scanner. METHODS: We constructed a flat-panel VP-PET device using 32 high-resolution detectors, each containing a 4  ×  4 MPPC array and 16  ×  16 LYSO crystals of 1.0  ×  1.0  ×  3.0 mm3 each. The flat-panel detectors can be positioned around a patient's body anywhere in the imaging field-of-view (FOV) of a Siemens Biograph 40 PET/CT scanner by a robotic arm. New hardware, firmware and software have been developed to support the additional detector signals without compromising a scanner's native functions. We stepped a 22 Na point source across the axial FOV of the scanner to measure the sensitivity profile of the VP-PET device. We also recorded the coincidence events measured by the scanner detectors and by the VP-PET detectors when imaging phantoms of different sizes. To assess the improvement in the CRC of small lesions, we imaged an elliptical torso phantom measuring 316  ×  228  ×  162 mm3 that contains spherical tumors with diameters ranging from 3.3 to 11.4 mm with and without the VP-PET device. Images were reconstructed using a list mode Maximum-Likelihood Estimation-Maximization algorithm implemented on multiple graphics processing units (GPUs) to support the unconventional geometries enabled by a VP-PET system. The mean and standard deviation of the CRC were calculated for tumors of different sizes. Monte Carlo simulation was also conducted to image clusters of lesions in a torso phantom using a PET/CT scanner alone or the same scanner equipped with VP-PET devices. Receiver operating characteristic (ROC) curves were analyzed for three system configurations to evaluate the improvement in lesion detectability by the VP-PET device over the native PET/CT scanner. RESULTS: The repeatability in positioning the flat-panel detectors using a robotic arm is better than 0.15 mm in all three directions. Experimental results show that the average CRC of 3.3, 4.3, and 6.0 mm diameter tumors was 0.82%, 2.90%, and 5.25%, respectively, when measured by the native scanner. The corresponding CRC was 2.73%, 6.21% and 10.13% when imaged by the VP-PET insert device with the flat-panel detector under the torso phantom. These values may be further improved to 4.31%, 9.65% and 18.01% by a future dual-panel VP-PET insert device if DOI detectors are employed to triple its detector efficiency. Monte Carlo simulation results show that the tumor detectability can be improved by a VP-PET device that has a single flat-panel detector. The improvement is greater if the VP-PET device employs a dual-panel design. CONCLUSIONS: We have developed a prototype flat-panel VP-PET device and integrated it with a clinical PET/CT scanner. It significantly enhances the contrast of lesions, especially for those that are borderline detectable by the native scanner, within regions-of-interest specified by users. Simulation demonstrated the enhancement in lesion detectability with the VP-PET device. This technology may become a cost-effective solution for organ-specific imaging tasks.

Understanding health care avoidance and initial help-seeking behavior in German veterans: a theory of planned behavior.

OBJECTIVE: To gain initial insights into salient beliefs of former German soldiers (veterans) about the use of mental health services. DATA SOURCE: Narrative interviews with former German soldiers (veterans) were conducted in 2016. DATA COLLECTION/EXTRACTION METHOD: Forty-three interviews were transcribed and analyzed thematically based on the theoretical framework of the theory of planned behavior. From within the behavorial, normative, and control beliefs, the salient beliefs were identified. PRINCIPAL FINDINGS: Four groups of salient beliefs were identified, described, and named: "Autarky", "Ineffectiveness", "Heteronomy", and "Incapacity". CONCLUSION: Interventions and campaigns addressing these four specific groups of beliefs may lead to higher health service use rates. However, as a result of methodological limitations of the study design, the conclusion remains tentative.

Stigma and its impact on the families of former soldiers of the German Armed Forces: an exploratory study.

BACKGROUND: Military families who have a family member with a mental illness see themselves confronted with many demands. Stigmatization is one of these challenges. Stigmatization affects not only the individual who suffers from a mental illness but also other family members via stigma by association and vicarious stigma. Stigma by association occurs when mental illness stigma spills over to individuals associated with an individual with a mental illness. Vicarious stigma describes the suffering of family members when they note the impact of stigma on their relative with mental illness. As a societal phenomenon, stigma plays out in social interactions and might therefore influence the social networks of families. It is also associated with healthcare utilization. METHOD: Narrative interviews were conducted with 15 family members (partners, spouses, parents and children) of former soldiers of the German Armed Forces with a service-induced mental illness. The transcribed interview data were analyzed using a thematic analysis approach, in which codes were formed and emerging themes were systemized. Relationships between stigma, the families' reactions to it, its effects on their social relationships and its interference with their healthcare utilization were analyzed. RESULTS: This study provides a detailed description of how relatives of former German soldiers with mental health problems experience stigma by association and vicarious stigma. Their perceptions are shown in a model that describes stigma-related attitudes, reactions to them and their effects on the social relationships of former soldiers' families. These families felt stigmatized because of the former soldiers' mental illness (mental illness stigma) and the military context in which it occurred (former soldier stigma). They reacted with nondisclosure, anger, acceptance and self-blame. Stigma was associated with smaller and weaker social networks that were characterized by social exclusion, self-segregation and conflicts with extended family, friends and colleagues. Stigma also affected the families' healthcare utilization. CONCLUSIONS: Urgently needed anti-stigma campaigns, particularly in the civilian context, should address the stigmatization of both mental illness and the military participation of the families affected. They should consider the needs of both former soldiers with a mental illness and their families.

Multiscale Analysis of Mineralized Collagen Combining X-ray Scattering and Fluorescence with Raman Spectroscopy under Controlled Mechanical, Thermal, and Humidity Environments.

Biological materials, such as mineralized collagen, are structured over many length scales. This represents a challenge for quantitative characterization, in particular when complex specimen environments are required. This paper describes an approach based on synchrotron X-ray scattering and Raman spectroscopy to analyze the structure of biological materials from the molecular to the macroscopic range in controlled environments including humidity, temperature, and mechanical load. This is achieved by a new setup, installed at the microfocus beamline µSpot at the BESSY II synchrotron in Berlin, where a perforated mirror is placed into the X-ray beam to focus laser light into the specimen to excite a Raman signal. We show that this allows simultaneous micrometer-scale mapping of chemical groups in the organic matrix together with the size and orientation of mineral nanoparticles in mineralized collagen. The approach is especially suitable to studying time-dependent modifications of materials, such as molecular changes during tensile deformation, dehydration, or thermal denaturation.

[Barriers to treatment-seeking among German veterans: expert interviews]. / Barrieren der Inanspruchnahme von Psychotherapie ehemaliger Soldatinnen und Soldaten der Bundeswehr (Veteranen). Eine Expertenbefragung.

BACKGROUND: The number of service members of the German armed forces suffering from deployment-related mental health problems is increasing. However, less than 50 % seek professional help, and there is little knowledge about the barriers to treatment-seeking. METHODS: The article presents data gathered by the Delphi technique combined with focus groups from 55 health service experts regarding the evaluated barriers to treatment-seeking among German veterans. FINDINGS: According to the interviewed experts, major contextual barriers to treatment-seeking include: 1) intimidating processes and structures, 2) actual stigmatization and discrimination, and 3) health service deficits. Major individual barriers to treatment were: 4) health beliefs, self-perception and fear of stigmatization, and 5) avoidance behavior related to psychopathology. In addition, there is another both contextual and individual barrier, i.e., 6) information deficits. INTERPRETATION: Individual internal factors like the soldiers' self-perception and their fear of being stigmatized were considered important barriers to treatment-seeking. The experts' opinion about avoidance behavior related to psychopathology and deficits in health services and information coincides with international findings. Compared to research in other countries, actual stigmatization and discrimination were regarded to be an important barrier in itself. According to our findings daunting/intimidating processes and structures like time-consuming and complex expert medical reports rather seem to be a German phenomenon.

Performance test of an LSO-APD detector in a 7-T MRI scanner for simultaneous PET/MRI.

UNLABELLED: PET combined with CT has proven to be a valuable multimodality imaging device revealing both functional and anatomic information. Although PET/CT has become completely integrated into routine clinical application and also has been used in small-animal imaging, CT provides only limited soft-tissue contrast and, in preclinical studies, exposes the animal to a relatively high radiation dose. Unlike CT, MRI provides good soft-tissue contrast even without application of contrast agents and, furthermore, does not require ionizing radiation. METHODS: This project focused on combining a high-resolution PET scanner with a 7-T MRI system for animal research. Because classic PET detectors based on photomultiplier tubes cannot be used in high magnetic fields, we used a detector technology based on 10 x 10 lutetium oxyorthosilicate crystal arrays and 3 x 3 avalanche photodiode arrays. A ring of such PET detectors will ultimately be used as an insert for the 119-mm-diameter MRI bore. RESULTS: Initial measurements with 1 PET detector module in the 7-T field during application of MRI sequences were encouraging. Position profiles from the PET detectors and a first MR image of a mouse could be acquired simultaneously. CONCLUSION: Further work will concentrate on the construction of a full PET detector ring with compact, integrated electronics.

Evaluation of transmission methodology and attenuation correction for the microPET Focus 220 animal scanner.

An accurate, low noise estimate of photon attenuation in the subject is required for quantitative microPET studies of molecular tracer distributions in vivo. In this work, several transmission-based measurement techniques were compared, including coincidence mode with and without rod windowing, singles mode with two different energy sources ((68)Ge and (57)Co), and postinjection transmission scanning. In addition, the effectiveness of transmission segmentation and the propagation of transmission bias and noise into the emission images were examined. The (57)Co singles measurements provided the most accurate attenuation coefficients and superior signal-to-noise ratio, while (68)Ge singles measurements were degraded due to scattering from the object. Scatter correction of (68)Ge transmission data improved the accuracy for a 10 cm phantom but over-corrected for a mouse phantom. (57)Co scanning also resulted in low bias and noise in postinjection transmission scans for emission activities up to 20 MBq. Segmentation worked most reliably for transmission data acquired with (57)Co but the minor improvement in accuracy of attenuation coefficients and signal-to-noise may not justify its use, particularly for small subjects. We conclude that (57)Co singles transmission scanning is the most suitable method for measured attenuation correction on the microPET Focus 220 animal scanner.

Performance evaluation of the microPET focus: a third-generation microPET scanner dedicated to animal imaging.

UNLABELLED: The microPET Focus is the latest generation microPET system dedicated to high-resolution animal imaging and incorporates several changes to enhance its performance. This study evaluated the basic performance of the scanner and compared it with the Primate (P4) and Rodent (R4) models. METHODS: The system consists of 168 lutetium oxyorthosilicate (LSO) detectors arranged in 4 contiguous rings, with a 25.8-cm diameter and a 7.6-cm axial length. Each detector consists of a 12 x 12 LSO crystal array of 1.51 x 1.51 x 10.00 mm3 elements. The scintillation light is transmitted to position-sensitive photomultiplier tubes via optical fiber bundles. The system was evaluated for its energy and spatial resolutions, sensitivity, and noise equivalent counting rate. Phantoms and animals of varying sizes were scanned to evaluate its imaging capability. RESULTS: The energy resolution averages 18.5% for the entire system. Reconstructed image resolution is 1.3-mm full width at half maximum (FWHM) at the center of field of view (CFOV) and remains under 2 mm FWHM within the central 5-cm-diameter FOV in all 3 dimensions. The absolute sensitivity of the system is 3.4% at the CFOV for an energy window of 250-750 keV and a timing window of 10 ns. The noise equivalent counting-rate performance reaches 645 kcps for a mouse-size phantom using 250- to 750-keV and 6-ns settings. Emission images of a micro-Derenzo phantom demonstrate the improvement in image resolution compared with previous models. Animal studies exhibit the capability of the system in studying disease models using mouse, rat, and nonhuman primates. CONCLUSION: The Focus has significantly improved performance over the previous models in all areas evaluated. This system represents the state-of-the-art scintillator-based animal PET scanner currently available and is expected to advance the potential of small animal PET.

Cardiac PET imaging in mice with simultaneous cardiac and respiratory gating.

Gating firmware and software were developed for the microPET II small animal scanner. The measured cardiac and respiratory signals were collected and converted to TTL gating signals by a Biopac MP150 data acquisition system and sent to microPET II through two BNC connectors on the front panel. During acquisition, the coincidence monitor takes the average of the last eight gate input cycles and inserts this into the list mode data stream on the falling edge of the gating pulse. This value is then used to determine the current time interval of the next gate cycle when the list mode data are sorted into sinograms. The gating firmware and software were validated by an experiment using a rotating point source. Mouse heart (18F-FDG) and bone (18F(-)) imaging was performed with simultaneous cardiac and respiratory gating. It was clearly demonstrated that the contractile function of the mouse heart can be studied by cardiac-gated imaging with microPET II. The left ventricular volumes at different times of the cardiac cycle were measured and the ejection fraction was calculated. In the bone scan, no detectable movement caused by heart contraction was observed. Respiratory motion was more subtle with virtually no motion for more than 75% of the respiratory cycle. The motion of the mouse heart and bones in the thorax caused by respiration was less than 1 mm. It appears with the current resolution of PET, and the small fraction of the respiratory cycle in which motion occurs, that respiratory gating is probably not necessary for most mouse cardiac studies.

Is trait resilience characterized by specific patterns of attentional bias to emotional stimuli and attentional control?

BACKGROUND AND OBJECTIVES: Attentional processes have been suggested to play a crucial role in resilience defined as positive adaptation facing adversity. However, research is lacking on associations between attentional biases to positive and threat-related stimuli, attentional control and trait resilience. METHODS: Data stem from the follow-up assessment of a longitudinal study investigating mental health and related factors among German soldiers. Trait resilience was assessed with the Connor-Davidson Resilience Scale and attentional control with the Attentional Control Scale. A subset of n = 198 soldiers also completed a dot probe task with happy, neutral and threatening faces. RESULTS: Attentional control was positively related to trait resilience. Results revealed no associations between both attentional biases and trait resilience. However, there was a negative association between attentional bias to threat and trait resilience when attentional control was low and a positive association between attentional bias to threat and trait resilience when attentional control was high. No such associations were found for attentional bias to positive stimuli. LIMITATIONS: Generalizability to other populations may be limited since we exclusively focused on male soldiers. Also, the cross-sectional design does not allow for causal conclusions. CONCLUSIONS: Findings suggest that attentional processing may promote trait resilience. Future research on preventive interventions should consider these findings.

Stress exposure and the risk for the onset of alcohol use disorders and nicotine dependence in deployed military personnel: the role of prior internalizing disorders.

OBJECTIVE: This prospective study aimed to investigate whether prior internalizing disorders (PIDs) moderate the relationship between stress exposure (SE) and the onset of alcohol use disorders (AUDs) and nicotine dependence (ND) in deployed military personnel. METHODS: 358 male soldiers were examined directly before and 12months after return from deployment using standardized interviews. Combat experiences, concerns about family disruptions, and difficult living and working environment were assessed as different aspects of SE. PID diagnoses (mood disorders (PMDs), anxiety disorders (PADs)) and substance use disorders were defined according to the DSM-IV-TR. RESULTS: PMDs were related to a stronger association between concerns about family disruptions and the risk of AUD onset (OR=7.7, 95% CI 1.8-32.8, p=0.006). The number of PID diagnoses (OR per diagnosis: 1.7, 95% CI 1.0-2.8, p=0.036) and PADs (OR: 2.6, 95% CI 1.1-6.3, p=0.038) were further related to a stronger association between difficult living and working environment and the risk of AUD onset. With regard to ND, PMDs were related to a weaker association between difficult living and working environment and the risk of ND onset (OR=0.4, 95% CI 0.2-0.8, p=0.013). CONCLUSIONS: PIDs might be related to an increased risk for the onset of AUDs but not ND following SE. This effect is probably restricted to specific constellations of PADs, PMDs, comorbid PIDs and specific aspects of SE. These critical constellations of PIDs and SE might be a promising target for future research and could contribute to the development of preventive measures to reduce the risk of AUDs following SE.

MicroPET II: design, development and initial performance of an improved microPET scanner for small-animal imaging.

MicroPET II is a second-generation animal PET scanner designed for high-resolution imaging of small laboratory rodents. The system consists of 90 scintillation detector modules arranged in three contiguous axial rings with a ring diameter of 16.0 cm and an axial length of 4.9 cm. Each detector module consists of a 14 x 14 array of lutetium oxyorthosilicate (LSO) crystals coupled to a multi-channel photomultiplier tube (MC-PMT) through a coherent optical fibre bundle. Each LSO crystal element measures 0.975 mm x 0.975 mm in cross section by 12.5 mm in length. A barium sulphate reflector material was used between LSO elements leading to a detector pitch of 1.15 mm in both axial and transverse directions. Fused optical fibre bundles were made from 90 microm diameter glass fibres with a numerical aperture of 0.56. Interstitial extramural absorber was added between the fibres to reduce optical cross talk. A charge-division readout circuit was implemented on printed circuit boards to decode the 196 crystals in each array from the outputs of the 64 anode signals of the MC-PMT. Electronics from Concorde Microsystems Inc. (Knoxville, TN) were used for signal amplification, digitization, event qualification, coincidence processing and data capture. Coincidence data were passed to a host PC that recorded events in list mode. Following acquisition, data were sorted into sinograms and reconstructed using Fourier rebinning and filtered hackprojection algorithms. Basic evaluation of the system has been completed. The absolute sensitivity of the microPET II scanner was 2.26% at the centre of the field of view (CFOV) for an energy window of 250-750 keV and a timing window of 10 ns. The intrinsic spatial resolution of the detectors in the system averaged 1.21 mm full width at half maximum (FWHM) when measured with a 22Na point source 0.5 mm in diameter. Reconstructed image resolution ranged from 0.83 mm FWHM at the CFOV to 1.47 mm FWHM in the radial direction, 1.17 mm FWHM in the tangential direction and 1.42 mm FWHM in the axial direction at 1 cm offset from the CFOV. These values represent highly significant improvements over our earlier microPET scanner (approximately fourfold sensitivity increase and 25-35% improvement in linear spatial resolution under equivalent operating conditions) and are expected to be further improved when the system is fully optimized.

Optimization and performance evaluation of the microPET II scanner for in vivo small-animal imaging.

MicroPET II is a newly developed PET (positron emission tomography) scanner designed for high-resolution imaging of small animals. It consists of 17,640 LSO crystals each measuring 0.975 x 0.975 x 12.5 mm3, which are arranged in 42 contiguous rings, with 420 crystals per ring. The scanner has an axial field of view (FOV) of 4.9 cm and a transaxial FOV of 8.5 cm. The purpose of this study was to carefully evaluate the performance of the system and to optimize settings for in vivo mouse and rat imaging studies. The volumetric image resolution was found to depend strongly on the reconstruction algorithm employed and averaged 1.1 mm (1.4 microl) across the central 3 cm of the transaxial FOV when using a statistical reconstruction algorithm with accurate system modelling. The sensitivity, scatter fraction and noise-equivalent count (NEC) rate for mouse- and rat-sized phantoms were measured for different energy and timing windows. Mouse imaging was optimized with a wide open energy window (150-750 keV) and a 10 ns timing window, leading to a sensitivity of 3.3% at the centre of the FOV and a peak NEC rate of 235,000 cps for a total activity of 80 MBq (2.2 mCi) in the phantom. Rat imaging, due to the higher scatter fraction, and the activity that lies outside of the field of view, achieved a maximum NEC rate of 24,600 cps for a total activity of 80 MBq (2.2 mCi) in the phantom, with an energy window of 250-750 keV and a 6 ns timing window. The sensitivity at the centre of the FOV for these settings is 2.1%. This work demonstrates that different scanner settings are necessary to optimize the NEC count rate for different-sized animals and different injected doses. Finally, phantom and in vivo animal studies are presented to demonstrate the capabilities of microPET II for small-animal imaging studies.

Personal values in soldiers after military deployment: associations with mental health and resilience.

BACKGROUND: After military deployment, soldiers are at an increased risk of developing posttraumatic psychiatric disorders. The correlation of personal values with symptoms, however, has not yet been examined within a military context. METHOD: Schwartz's Portrait Values Questionnaire (PVQ), the Posttraumatic Stress Diagnostic Scale (PDS), and the 11-item version of the Resilience Scale (RS-11) were completed by 117 soldiers of the German Armed Forces who had recently been deployed to Afghanistan (n=40 undergoing initial psychiatric treatment, n=77 untreated). RESULTS: Logistic regression showed that the value types of hedonism (-), power (-), tradition (+), and universalism (+) were significantly correlated with the probability and severity of PTSD and whether the participant was in treatment or not. The effects were partially mediated by the RS-11 scale values. CONCLUSIONS: Value types seem to be associated with psychiatric symptoms in soldiers after deployment. These results could contribute to the further development of therapeutic approaches.