The DRESDEN PLATFORM is a research hub for ultra-high dose rate radiobiology

The recently observed FLASH effect describes the observation of normal tissue protection by ultra-high dose rates (UHDR), or dose delivery in a fraction of a second, at similar tumor-killing efficacy of conventional dose delivery and promises great benefits for radiotherapy patients. Dedicated studies are now necessary to define a robust set of dose application parameters for FLASH radiotherapy and to identify underlying mechanisms. These studies require particle accelerators with variable temporal dose application characteristics for numerous radiation qualities, equipped for preclinical radiobiological research. Here we present the DRESDEN PLATFORM, a research hub for ultra-high dose rate radiobiology. By uniting clinical and research accelerators with radiobiology infrastructure and know-how, the DRESDEN PLATFORM offers a unique environment for studying the FLASH effect. We introduce its experimental capabilities and demonstrate the platform's suitability for systematic investigation of FLASH by presenting results from a concerted in vivo radiobiology study with zebrafish embryos. The comparative pre-clinical study was conducted across one electron and two proton accelerator facilities, including an advanced laser-driven proton source applied for FLASH-relevant in vivo irradiations for the first time. The data show a protective effect of UHDR irradiation up to [Formula: see text] and suggests consistency of the protective effect even at escalated dose rates of [Formula: see text]. With the first clinical FLASH studies underway, research facilities like the DRESDEN PLATFORM, addressing the open questions surrounding FLASH, are essential to accelerate FLASH's translation into clinical practice.

Spectral-temporal measurement capabilities of third-order correlators

We present a method extending scanning third-order correlator temporal pulse evolution measurement capabilities of high power short pulse lasers to spectral sensitivity within the spectral range exploited by typical chirped pulse amplification systems. Modelling of the spectral response achieved by angle tuning of the third harmonic generating crystal is applied and experimentally validated. Exemplary measurements of spectrally resolved pulse contrast of a Petawatt laser frontend illustrate the importance of full bandwidth coverage for the interpretation of relativistic laser target interaction in particular for the case of solid targets.

Abstract TP54: Organized Post-stroke Care: Results From A Prospective Cohort Study

Introduction: Pilot data suggests that organized post-stroke care enhances achievement of secondary prevention goals in stroke patients. We aimed to further investigate whether organized post-stroke care favourably affects stroke recurrence and survival.

Methods: Prospective, quasi-experimental study of consecutive stroke patients admitted at two tertiary stroke centers in Saxony, Germany. According to health insurance provider status, patients were non-randomly assigned to either 12-months post-stroke pathway plus conventional care or conventional care alone. The organized post-stroke care pathway was facilitated by certified case managers and included pre-scheduled home- and phone visits aiming at educational intervention and achievement of guideline-based secondary prevention treatment goals. Primary outcomes were stroke recurrence and vascular death at 12-months. Further outcomes included favourable functional outcome (i.e. mRS 0-1), health-related quality of life and vascular risk factor control at 12-months.

Results: In total, 1109 patients were recruited between 11/2011 and 12/2020. Of these, 1009 patients (91%) were assigned to organized post-stroke care and 100 (9%) to conventional care (mean age 70.6±12.8 years, 54% male, median NIHSS 3 [IQR, 1-5] points, 77.5% AIS, 17.9% TIA and 4.6% ICH). Baseline demographics and clinical characteristics were well balanced between both groups (p≥0.05). At 12-months, recurrent stroke rate was lower in the post-stroke care than in the conventional care group (5.5% vs. 14%; aOR 0.35, 95%CI 0.18-0.66; p=0.001). This association was not modified by stroke severity (TIA/minor stroke versus major stroke). Vascular death occurred in 0.2% in the post-stroke care and 3% in the conventional care group (aOR 0.07, 95%CI 0.01-0.41; p=0.003). Organized post-stroke care more frequently yielded individual treatment goals for hypertension, lipids, HbA1c, body-mass-index and secondary prevention adherence than conventional care (p<0.05).

Conclusions: Our results substantiate the effectiveness of case management-based post-stroke care in unselected stroke patients.

Knowledge transfer as a tool towards improvement of cancer care in low- and middle-income countries. 6th European Roundtable Meeting (ERTM), June 14th, 2019, Berlin, Germany

PURPOSE

To identify key factors for the best practice of knowledge transfer from high-income settings to low- and middle-income settings.

RESULTS

Interactive sessions led to the identification of European learnings that can and should be shared beyond Europe. Furthermore, methods were characterised which may lead to successful knowledge transfer with subsequent quality improvement.

CONCLUSION

To ensure successful implementation of knowledge and new methods, political support is extremely important. A strong focus should be an improvement of collaboration and network development. Rehabilitation, early and late pallative care, cost effectiveness and long-term follow-up are priorities. Limitations are budget constraints which limit the execution of NCCPs.

Demonstration of a beam loaded nanocoulomb-class laser wakefield accelerator

Laser-plasma wakefield accelerators have seen tremendous progress, now capable of producing quasi-monoenergetic electron beams in the GeV energy range with few-femtoseconds bunch duration. Scaling these accelerators to the nanocoulomb range would yield hundreds of kiloamperes peak current and stimulate the next generation of radiation sources covering high-field THz, high-brightness X-ray and γ-ray sources, compact free-electron lasers and laboratory-size beam-driven plasma accelerators. However, accelerators generating such currents operate in the beam loading regime where the accelerating field is strongly modified by the self-fields of the injected bunch, potentially deteriorating key beam parameters. Here we demonstrate that, if appropriately controlled, the beam loading effect can be employed to improve the accelerator's performance. Self-truncated ionization injection enables loading of unprecedented charges of ∼0.5 nC within a mono-energetic peak. As the energy balance is reached, we show that the accelerator operates at the theoretically predicted optimal loading condition and the final energy spread is minimized.Higher beam quality and stability are desired in laser-plasma accelerators for their applications in compact light sources. Here the authors demonstrate in laser plasma wakefield electron acceleration that the beam loading effect can be employed to improve beam quality by controlling the beam charge.

Efficient laser-driven proton acceleration from cylindrical and planar cryogenic hydrogen jets

We report on recent experimental results deploying a continuous cryogenic hydrogen jet as a debris-free, renewable laser-driven source of pure proton beams generated at the 150 TW ultrashort pulse laser Draco. Efficient proton acceleration reaching cut-off energies of up to 20 MeV with particle numbers exceeding 109 particles per MeV per steradian is demonstrated, showing for the first time that the acceleration performance is comparable to solid foil targets with thicknesses in the micrometer range. Two different target geometries are presented and their proton beam deliverance characterized: cylindrical (∅ 5 μm) and planar (20 μm × 2 μm). In both cases typical Target Normal Sheath Acceleration emission patterns with exponential proton energy spectra are detected. Significantly higher proton numbers in laser-forward direction are observed when deploying the planar jet as compared to the cylindrical jet case. This is confirmed by two-dimensional Particle-in-Cell (2D3V PIC) simulations, which demonstrate that the planar jet proves favorable as its geometry leads to more optimized acceleration conditions.

The stroke east Saxony pilot project for organized post-stroke care: a case-control study

BACKGROUND

Low adherence to secondary prevention guidelines in stroke survivors may increase the risk for recurrent stroke and adversely impact quality of life. We aimed to determine the feasibility of a self-developed standardized post-stroke pathway and its impact on secondary stroke prevention and long-term outcome in patients with acute stroke.

METHODS

Consecutive patients with acute stroke were prospectively included in a standardized post-stroke pathway accomplished through a single certified CM (case manager), which comprised educational discussions and quarterly checkups for vascular risk factors and adherence to antithrombotic/anticoagulant medication in addition to usual care. At 12 months, we compared achieved target goals for secondary prevention, functional outcome, stroke recurrence, and vascular death with age- and gender-matched controls that received only usual care after stroke.

RESULTS

We included 45 cases and 45 controls. The following target goals were more frequently achieved in CM-patients than in controls: blood pressure (100% vs. 46.2%, P < 0.001), cholesterol (100% vs. 74.4%, P < 0.001), and body mass index (67.4% vs. 46.2%, P = 0.052). The CM-intervention emerged as an independent predictor of favorable functional outcome (mRS ≤ 2) at 12 months after adjusting for stroke severity and systemic thrombolysis (OR: 4.27; 95%CI:1.2-15.21; P = 0.025). Quality of life was rated significantly higher in CM-patients than in controls (P = 0.049). As opposed to controls, none of the cases experienced a recurrent stroke (0% vs. 13.3%; P = 0.026) or suffered from vascular death (0% vs. 6.7%; P = 0.242).

CONCLUSIONS

Our pilot data suggest that organized post-stroke care enhances achievement of secondary prevention goals. Its possible effect on stroke recurrence, long-term disability, and quality of life is currently investigated in a prospective cohort study.

Improving cancer care in Europe: Which institutional health structures might be beneficial and why? 1. European Roundtable Meeting (ERTM), 16th May 2014, Berlin, Germany

PURPOSE

Bringing the knowledge and expertise of different European countries and the European Commission together for an analysis of the different factors being beneficent or rather opposing for high quality in cancer care. A specific focus is set on the structures and views in European nations on implementation processes.

RESULTS

Due to the variation of National Cancer Control Plans (NCCPs) the preferences for implementation strategies differ. For quality achievement the involvement of the different stakeholders is beneficial. Common sense was the importance of NCCPs. However, it was consensus between participants that a bottom-up approach that considers the needs of different professional groups involved in cancer care and also the views of patients is of critical importance for successful implementation. Functioning cancer registries and evidence-based guidelines with standard of care are fundamental for quality measurement.

CONCLUSIONS

There is consensus between participants of the meeting that NCCPs are essential for improvement of cancer care. However, national preferences and the views of patients and caregivers have to be included to guarantee successful implementation.

Abstract T P383: The Stroke East Saxony Pilot Project For Organized Post-Stroke Care: A Case-Control Study

Background: Currently there is no standardized guidance on post-stroke management and adherence to secondary stroke prevention guidelines is modest in stroke survivors. We aimed to determine the feasibility of a self-developed evidence-based post-stroke pathway and its impact on secondary stroke prevention and long-term functional outcome.

Methods: Acute ischemic stroke patients were prospectively included in a standardized poststroke pathway facilitated by a single certified case manager (CM). The one-year pathway comprised educational discussions on stroke as well as quarterly check-ups for vascular risk factors, life-style changes and adherence to antithrombotic/anticoagulant therapy. The CM intervened when deviations from stroke prevention guidelines were present and if judged necessary. At 12 months, we compared achieved target goals for secondary prevention, functional outcome, stroke recurrence and vascular death with age- and gender-matched controls that received usual post-stroke care.

Results: We included 45 cases and 45 controls. At 12 months, the following target goals were more frequently achieved in patients with CM than in controls: blood pressure (100% vs. 46%, p<.001), cholesterol (100% vs. 74%, p<.001) and body-mass-index (67% vs. 46%, p=.053). No differences were found in nicotine abstinence (p=n.s.), HbA1c (p=n.s.) and adherence to antithrombotics/anticoagulants (p=n.s.). CM emerged as an independent predictor of favorable functional outcome (mRS≤2) at 12 months after adjusting for baseline stroke severity and IV thrombolysis (OR: 4.27; 95%CI: 1.2-15.21; p=.025). As opposed to the controls, none of the cases experienced a recurrent stroke (0% versus 13%; p=.003) or suffered from vascular death (0% versus 7%; p=.242) during the follow-up period.

Conclusions: Our pilot data suggest that organized post-stroke care may enhance achievement of secondary prevention goals. Its possible effect on stroke recurrence, long-term disability and quality of life is currently investigated in a prospective cohort study.

Large hospital outbreak of KPC-2-producing Klebsiella pneumoniae: investigating mortality and the impact of screening for KPC-2 with polymerase chain reaction

BACKGROUND

Multi-drug-resistant Klebsiella pneumoniae carbapenemase (KPC)-2-producing K. pneumoniae are an increasing cause of healthcare-associated infections worldwide.

AIMS

To investigate the impact of clinical infection on mortality, and examine the effect of use of KPC-2-specific polymerase chain reaction (PCR) on the time to contact isolation during an outbreak.

METHODS

Cases were defined as patients clinically infected or colonized with KPC-2-producing K. pneumoniae between June 2010 and July 2012. Cases were described by demographic and health characteristics, and the association between infection and mortality, adjusted for comorbidities and demographic characteristics, was determined using Poisson regression with robust standard errors. A comparison was made between the time to contact isolation with a culture-based method and PCR using Wilcoxon's rank sum test.

FINDINGS

Of 72 cases detected, 17 (24%) had undergone transplantation and 21 (29%) had a malignancy. Overall, 35 (49%) cases were clinically infected, with pneumonia and sepsis being the most common infections. Infection was an independent risk factor for mortality (risk ratio 1.67, 95% confidence interval 0.99-2.82). The median time to contact isolation was 1.5 days (range 0-21 days) using PCR and 5.0 days (range 0-39 days) using culture-based methods (P = 0.003). Intermittent negative tests were observed in 48% (14/29) of cases tested using culture-based methods.

CONCLUSION

KPC-2-producing K. pneumoniae mainly affect severely ill patients. Half of the cases developed clinical infection, associated with increased risk of death. As PCR accelerates isolation and provides the opportunity for preventive measures in colonized cases, its use should be implemented promptly during outbreaks. Further studies are needed to enhance knowledge about KPC detection patterns and to adjust screening guidelines.

Abstract W P136: SOS CARE: The Stroke East Saxony Pilot Project for Integrated Care Pathway and Case Management After Stroke

Background: We developed a standardized pathway for post-stroke care facilitated through a case manager (CM) to ensure minimization of risk factors, life-style changes and continuation of secondary prevention medication.

Methods: Consecutive acute stroke patients were prospectively assigned to a certified CM. The 1-year post-stroke care pathway comprised initial educational discussion, personal patients’ home visits and quarterly telephone contacts. Further personal contacts were conducted when judged necessary. Target values for vascular risk factors were pre-defined according to current stroke guidelines, compared with regular check-ups and intervened when necessary. A closing meeting including assessment of stroke recurrence was performed.

Results: Between 12/2011 and 07/2013 we enrolled 74 of 111 screened patients: 57% male, mean age 71+/-14 yrs, median NIHSS 2 (range 0-16), 76% ischemic, 4% hemorrhagic stroke and 20% TIA. Of 74 patients, 10 refused follow-up care. Overall, 356 home visits (4.8/patient) and 1233 phone contacts (16.7/patient) were conducted. One hundred-eighty seven specific interventions were necessary mostly due to missing medication, non-compliance and social needs. Achieved vascular risk factor goals are presented in the Table. No recurrent stroke occurred. Among screened patients who refused CM, stroke recurrence rate was 22% after 12 months.

Conclusion: The preliminary data of our pilot project suggest that case management is capable of achieving predefined goals for secondary prevention. To investigate its impact on stroke recurrence risk and prevention of long-term care dependency, we initiate a randomized controlled trial.

Radioisotope-dilution technique for determining endogenous manganese in feces of the growing rat

A conventional balance study with growing rats was conducted to evaluate experimental conditions for determining endogenous fecal manganese (Mn) excretion and, hence, true Mn absorption by the isotope-dilution technique. Thirty-four rats, with a mean initial live weight of 60 g, allotted to three groups of 8 animals and one group of 10 animals, were injected intramuscularly with a(54)Mn tracer dose and sacrificed after 4, 8, 12, and 16 d, respectively.In liver and serum, the specific radioactivity of Mn was the lowest among the tissues analyzed and its exponential rate of decrease over the period of d 4-16 was the highest. During the 8-d period, from d 9-16, apparent Mn absorption averaged 14.1% of intake (128.5 μg Mn/d). Assuming that the specific activity of Mn in liver of d 11 or, alternatively, in serum of d 16, was on the average representative of that of endogenous Mn in feces of d 9-16, it was computed that Mn of endogenous origin accounted for 9.0 and 9.3% of the total fecal excretion of the metal, and that true absorption amounted to 21.9 and 22.1% of Mn intake, respectively.

True absorption and endogenous fecal excretion of manganese in relation to its dietary supply in growing rats

A conventional balance study with 48 male weanling rats was conducted to determine true absorption and endogenous fecal excretion of manganese (Mn) in relation to dietary Mn supply, following the procedures of a previously adapted isotope dilution technique. After 10 d on a diet with 1.5 ppm Mn, eight animals each were assigned to diets containing 1.5, 4.5, 11.2, 35, 65, or 100 ppm Mn on a dry-matter basis. Three days later, each rat was given an intramuscular(54)Mn injection and kept on treatment for a balance period of 16 d.Apparent Mn absorption assessed for the final 8 d, averaged 8.6 μg/d without significant treatment effects, although Mn intake ranged from 18.6 to 1200 μg/d, in direct relation to dietary Mn concentrations. Mean fecal excretion of endogenous Mn for the six treatments was 0.9, 2.7, 7.4, 11.0, 16.3, and 17.7 μg/d, respectively. These values delineate the rates to which true absorption exceeded apparent rates. True absorption, as percent of Mn intake, averaged 28.7, 15.9, 11.7, 6.1, 3.4, and 2.0, respectively, as compared with mean values of 23.9, 10.9, 6.2, 3.4, 1.2, and 0.5 for percent apparent absorption. It was concluded that both true absorption and endogenous fecal excretion markedly responded to Mn nutrition and that the reduction in the efficiency of true absorption was quantitatively the most significant homeostatic response for maintaining stable Mn concentrations in body tissues.