Source term calculation and validation for 18F-production with a cyclotron for medical applications at HZDR

In this document we present the calculation and experimental validation of a source term for ¹⁸F-production with a cyclotron for medical applications operating at 18 MeV proton energy and 30 μA proton current. The Monte Carlo codes MCNP6 and FLUKA were used for the calculation of the source term. In addition, the radiation field around the ¹⁸O-enriched water target was simulated with the two codes. To validate the radiation field obtained in the simulation, an experimental program has been started using activation samples which are placed close to the water target during an ¹⁸F-production run of the cyclotron. After the irradiation, the samples are analysed and the resulting activation is compared to Monte Carlo calculations of the expected sample activation. We find good agreement between simulations and experimental results, with most calculation to experiment (C/E) ratios well between 0.6 and 1.4.

Early Screening for Posttraumatic Stress Disorder in Inpatient Detoxification and Motivation Treatment: Results and Consequences

AIMS

Posttraumatic stress disorder (PTSD) is a significant comorbidity in substance use disorders (SUDs). While most studies have addressed trauma/PTSD in abstinent patients, little is known about trauma/PTSD in early detoxification treatment. The current study therefore addresses the systematic evaluation of trauma/PTSD in early inpatient detoxification.

METHODS

A cross-sectional survey was accomplished in three German-speaking clinics (n = 134) specialized in inpatient detoxification and motivation treatment. All measures are based on self-report using trauma-specific questionnaires and measures for general psychopathological burden.

RESULTS

Participation rate was 60.1% and patients did not show clinically obvious psychological distress during or after assessment. DSM-IV traumatic events were reported by 66.4%. Of the total sample, 38.1% screened positive for PTSD, and 14.9% screened positive for subsyndromal PTSD. PTSD patients reported significantly more childhood adversities and significantly higher scores in depression and -general psychopathology compared to subsyndromal PTSD and SUD-only patients.

CONCLUSIONS

Early and systematic evaluation of PTSD in SUD inpatient detoxification treatment is largely safe and yields important information for individual treatment. The high PTSD-rate and the high symptom load in SUD patients during inpatient detoxification treatment highlight the need for a more stringent address of trauma/PTSD in early SUD treatment.

Source terms, shielding calculations and soil activation for a medical cyclotron

Calculations of the shielding and estimates of soil activation for a medical cyclotron are presented in this work. Based on the neutron source term from the ¹⁸O(p,n)¹⁸F reaction produced by a 28 MeV proton beam, neutron and gamma dose rates outside the building were estimated with the Monte Carlo code MCNP6 (Goorley et al 2012 Nucl. Technol. 180 298-315). The neutron source term was calculated with the MCNP6 code and FLUKA (Ferrari et al 2005 INFN/TC_05/11, SLAC-R-773) code as well as with supplied data by the manufacturer. MCNP and FLUKA calculations yielded comparable results, while the neutron yield obtained using the manufacturer-supplied information is about a factor of 5 smaller. The difference is attributed to the missing channels in the manufacturer-supplied neutron source terms which considers only the ¹⁸O(p,n)¹⁸F reaction, whereas the MCNP and FLUKA calculations include additional neutron reaction channels. Soil activation was performed using the FLUKA code. The estimated dose rate based on MCNP6 calculations in the public area is about 0.035 µSv h^-1 and thus significantly below the reference value of 0.5 µSv h^-1 (2011 Strahlenschutzverordnung, 9 Auflage vom 01.11.2011, Bundesanzeiger Verlag). After 5 years of continuous beam operation and a subsequent decay time of 30 d, the activity concentration of the soil is about 0.34 Bq g^-1.

Pilot study of the application of magnetic bead protein profiling to the study of biomarkers in addiction research

OBJECTIVES

Proteomic technologies based on mass spectrometry are increasingly used as a valuable tool in clinical research allowing high-throughput protein and peptide profiling to be undertaken. Whilst previous research has focussed the application of this novel technology on the study of patients with disorders compared to comparable individuals from the healthy population, this current study seeks to determine the effect of successful treatment for alcoholism on the serum protein profile obtained.

METHODS

Serum samples were collected from patients after initial treatment for alcohol abuse and also 6 months after treatment. The serum samples were prepared for analysis using reverse phase magnetic bead fractionation and the resulting peptides analysed by matrix assisted laser desorption ionisation time-of-flight (MALDI-ToF) mass spectrometry.

RESULTS

Whilst the majority of the peptides detected by this approach exhibited constant levels between the two time points, three peptides were elevated at the 6-month time point compared to the initial sampling.

CONCLUSIONS

Whilst disorders with very clear biological causes (such as cancer) exhibit significantly different peptide profiles, psychiatric disorders such as alcohol addiction which are multifactorial show less obvious changes. Despite this the two groups of samples could statistically be distinguished by certain peptides expression levels.

Reactive oxygen species mediate functional differences in human radial and internal thoracic arteries from smokers

OBJECTIVE

Smoking not only increases the risk that coronary heart disease will develop but also morbidity and mortality in patients with known coronary atherosclerosis and after coronary artery bypass grafting. Excessive generation of reactive oxygen species (ROS) has been implicated as the final common pathway for the development of endothelial dysfunction in various cardiovascular risk factors. This study assessed the influence of smoking on two different human arteries routinely used as coronary artery bypass graft conduits.

METHODS

Isometric tension was recorded on discarded segments of human left internal thoracic artery (ITA) and the radial artery (RA) from smokers and nonsmokers.

RESULTS

The contractile response to endothelin-1 was significantly stronger in arteries from smokers than in those from nonsmokers. By contrast, endothelium-dependent relaxant responses to acetylcholine were attenuated in RA rings but enhanced in ITA rings from smokers. In additional experiments, 5-(&6)-chloromethyl-2'-7'-dichlorodihydro-fluorescein diacetate (DCDHF) was used to photochemically detect ROS by confocal imaging of intact ITA and RA. Enhanced production of ROS was induced by exposure of tissues to 28 degrees C. While during exposure to 28 degrees C, basal fluorescence emission was unchanged in ITA rings, it increased significantly in RA rings, indicating enhanced formation of ROS in this peripheral artery.

CONCLUSIONS

Data suggest that smoking induces endothelial dysfunction by increasing vascular ROS production. Different levels of endogenous antioxidant enzyme activities and the degree of atherosclerotic changes might modulate physiologic and pharmacologic vasoreactivity and be responsible for decreased graft patency of RA compared with ITA conduits, especially in active smokers.

Personality traits predict treatment outcome in alcohol-dependent patients

Personality traits are important individual characteristics modifying responses to therapy in various diseases. The aim of this study was to identify personality traits that may predict treatment outcome in alcohol-dependent patients. The present analysis was based on a total of 146 alcohol-dependent patients (109 male, 37 female) after detoxification. The variable of interest was treatment outcome (abstinence/relapse) after a 1-year follow-up. To identify personality traits as predictors of treatment outcome, 5 personality questionnaires (NEO 5-Factor Inventory, Temperament and Character Inventory, Eysenck Personality Questionnaire, Eysenck Impulsiveness-Venturesomeness-Empathy Scale and Sensation-Seeking Scale) were applied. Data analysis was performed by using a classification and regression tree analysis (CART; a nonparametric technique for data with a complex structure) in order to find a decision rule to predict treatment outcome from personality traits. The CART model identified psychoticism and persistence as the 2 most relevant discriminatory parameters, of which psychoticism was used as the first node in the model, classifying 64% of the patients correctly as relapsed and 12% correctly as abstinent. In addition, the risk of relapse was even higher in patients with a substantial score in psychoticism and a low score in persistence. When comparing relapsed and abstinent patients, further variables, such as scores for novelty seeking (20.9 +/- 5.5 vs. 18.5 +/- 5.9) and impulsiveness (8.4 +/- 3 vs. 7.2 +/- 3.5), showed significance. In addition, relapsed patients lived alone more often than abstinent patients (52 vs. 25%, p = 0.004). In conclusion, this analysis demonstrated that specific personality characteristics, namely psychoticism and persistence, are usable predictors for the risk of relapse in alcohol-dependent patients.

Antidepressive therapy with escitalopram improves mood, cognitive symptoms, and identity memory for angry faces in elderly depressed patients

Depression is a common disorder in the elderly handicapping patients with affective and cognitive symptoms. Because of their good tolerability relative to the older tricyclic compounds, selective serotonin reuptake inhibitors (SSRIs) are increasingly used for the treatment of depression in the elderly. Little is known about their effects on cognition in elderly patients. In the present 4-wk, single-centre, randomized, open-label trial we investigated the antidepressive effects of escitalopram, an SSRI, in 18 elderly depressed patients [mean age (+/-s.e.m.) 76.2+/-1.8 yr] compared to 22 healthy age-matched controls (mean age 76.9+/-1.8 yr). Affective and cognitive symptoms were assessed using the Geriatric Depression Scale (GDS), Mini-Mental State Examination (MMSE), and a face portrait recognition test to assess memory for happy and angry faces. Depressed patients prior to treatment had markedly reduced memory performance. Treatment with escitalopram improved affective and cognitive symptoms significantly. Furthermore, escitalopram treatment improved memory for negative facial stimuli. Control subjects confirmed the well- established memory bias favouring recognition of identities acquired with happy expressions. Importantly, this bias was absent in depressed patients prior to, but also after treatment. In conclusion, escitalopram, even after a relatively short treatment period, was effective in treating depression in the elderly and may help improve cognitive performance for social stimuli.