Publications by authors named "Manser P"

Background: Mild neurocognitive disorder (mNCD) is recognized as an early stage of dementia and is gaining attention as a significant healthcare problem due to current demographic changes and increasing numbers of patients. Timely detection of mNCD provides an opportunity for early interventions that can potentially slow down or prevent cognitive decline. Heart rate variability (HRV) may be a promising measure, as it has been shown to be sensitive to cognitive impairment.

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Purpose: Radiation therapy (RT) plays a key role in the management of esophageal cancer (EC). However, toxicities caused by proximity of organs at risk (OAR) and daily target coverage caused by interfractional anatomic changes are of concern. Daily online adaptive RT (oART) addresses these concerns and has the potential to increase OAR sparing and improve target coverage.

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Background: Non-coplanarity and mixed beam modality could be combined to further enhance dosimetric treatment plan quality. We introduce dynamic mixed beam arc therapy (DYMBARC) as an innovative technique that combines non-coplanar photon and electron arcs, dynamic gantry and collimator rotations, and intensity modulation with photon multileaf collimator (MLC). However, finding favorable beam directions for DYMBARC is challenging due to the large solution space, machine component constraints, and optimization parameters, posing a highly non-convex optimization problem.

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Background: Dose calculation in radiotherapy aims to accurately estimate and assess the dose distribution of a treatment plan. Monte Carlo (MC) dose calculation is considered the gold standard owing to its ability to accurately simulate particle transport in inhomogeneous media. However, uncertainties such as the patient's dynamically deforming anatomy can still lead to differences between the delivered and planned dose distribution.

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Neo-adjuvant chemoradiotherapy (CRT) and perioperative chemotherapy are different strategies for treating non-metastatic esophageal cancer (EC). The advantages of neo-adjuvant therapies are primarily seen in patients who achieve a pathologic complete response (pCR) and therefore show higher survival rates and better prognosis. In general, less than one-third of patients with EC experience pCR after neo-adjuvant therapies; however, patients with esophageal adenocarcinoma (AC) demonstrate lower rates of pCR compared to those with esophageal squamous cell carcinoma (SCC), respectively.

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Introduction: Primary membranous nephropathy (PMN) is most often caused by autoantibodies to phospholipase A2 receptor (PLA2R). M-PLACE (NCT04145440) is an open-label, phase 1b/2a study that assessed the safety and efficacy of the fully human anti-CD38 monoclonal antibody felzartamab in high-risk anti-PLA2R+ PMN.

Methods: Patients with newly diagnosed or relapsed PMN (cohort 1 [C1];  = 18) or PMN refractory to immunosuppressive therapy (IST) (cohort 2 [C2];  = 13) received 9 infusions of felzartamab 16 mg/kg in the 24-week treatment period, followed by a 28-week follow-up.

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Article Synopsis
  • Non-isocentric dynamic trajectory radiotherapy (DTRT) is a new way to target radiation therapy that uses special movements of the machine to hit the tumor from different angles without being stuck in one spot.
  • Researchers are creating a technique that helps decide the best path for the radiation beams, making sure they avoid healthy organs while still reaching the tumor effectively.
  • Comparisons of different treatment plans show that this new method can give better radiation distribution to the tumor and lower the radiation dose to nearby healthy organs.
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Dynamic trajectory radiotherapy (DTRT) and dynamic mixed-beam arc therapy (DYMBARC) exploit non-coplanarity and, for DYMBARC, simultaneously optimized photon and electron beams. Margin concepts to account for set-up uncertainties during delivery are ill-defined for electron fields. We develop robust optimization for DTRT&DYMBARC and compare dosimetric plan quality and robustness for both techniques and both optimization strategies for four cases.

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Background: Early detection of cognitive impairment is among the top research priorities aimed at reducing the global burden of dementia. Currently used screening tools have high sensitivity but lack specificity at their original cut-off, while decreasing the cut-off was repeatedly shown to improve specificity, but at the cost of lower sensitivity. In 2012, a new screening tool was introduced that aims to overcome these limitations - the Quick mild cognitive impairment screen (Qmci).

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Background: Vagally-mediated heart rate variability (vm-HRV) shows promise as a biomarker of internal training load (ITL) during exergame-based training or motor-cognitive training in general. This study evaluated the test-retest reliability of vm-HRV during exergaming in healthy older adults (HOA) and its validity to monitor ITL.

Methods: A within-subjects (repeated-measures) randomized study was conducted that included baseline assessments and 4 measurement sessions.

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Background: Coping with residual cognitive and gait impairments is a prominent unmet need in community-dwelling chronic stroke survivors. Motor-cognitive exergames may be promising to address this unmet need. However, many studies have so far implemented motor-cognitive exergame interventions in an unstructured manner and suitable application protocols remain yet unclear.

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Background: Exergame-based training is currently considered a more promising training approach than conventional physical and/or cognitive training.

Objectives: This study aimed to provide quantitative evidence on dose-response relationships of specific exercise and training variables (training components) of exergame-based training on cognitive functioning in middle-aged to older adults (MOA).

Methods: We conducted a systematic review with meta-analysis including randomized controlled trials comparing the effects of exergame-based training to inactive control interventions on cognitive performance in MOA.

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Introduction: The combination of exergame-based motor-cognitive training with resonance breathing guided by heart-rate variability biofeedback (HRV-BF) targets various relevant mechanisms of action to alleviate the pathological state in mild neurocognitive disorders (mNCD).

Methods: This randomized controlled trial (RCT) investigated the effectiveness of adding this novel intervention approach to usual care in mNCD. The individualized intervention was delivered via the "Brain-IT" training concept, which was iteratively co-designed, tested, and refined with patient and public involvement.

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Background And Purpose: Dynamic trajectory radiotherapy (DTRT) has been shown to improve healthy tissue sparing compared to volumetric arc therapy (VMAT). This study aimed to assess and compare the robustness of DTRT and VMAT treatment-plans for head and neck (H&N) cancer to patient-setup (PS) and machine-positioning uncertainties.

Materials And Methods: The robustness of DTRT and VMAT plans previously created for 46 H&N cases, prescribed 50-70 Gy to 95 % of the planning-target-volume, was assessed.

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Purpose: We evaluated the impact of partial volume correction (PVC) methods on the quantification of longitudinal [F]GTP1 tau positron-emission tomography (PET) in Alzheimer's disease and the suitability of describing the tau pathology burden temporal trajectories using linear mixed-effects models (LMEM).

Methods: We applied van Cittert iterative deconvolution (VC), 2-compartment, and 3-compartment, and the geometric transfer matrix plus region-based voxelwise methods to data acquired in an Alzheimer's disease natural history study over 18 months at a single imaging site. We determined the optimal PVC method by comparing the standardized uptake value ratio change (%ΔSUVR) between diagnostic and tau burden-level groups and the longitudinal repeatability derived from the LMEM.

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We compared dynamic trajectory radiotherapy (DTRT) to state-of-the-art volumetric modulated arc therapy (VMAT) for 46 head and neck cancer cases. DTRT had lower dose to salivary glands and swallowing structure, resulting in lower predicted xerostomia and dysphagia compared to VMAT. DTRT is deliverable on C-arm linacs with high dosimetric accuracy.

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Background: Non-coplanar techniques have shown to improve the achievable dose distribution compared to standard coplanar techniques for multiple treatment sites but finding optimal beam directions is challenging. Dynamic collimator trajectory radiotherapy (colli-DTRT) is a new intensity modulated radiotherapy technique that uses non-coplanar partial arcs and dynamic collimator rotation.

Purpose: To solve the beam angle optimization (BAO) problem for colli-DTRT and non-coplanar VMAT (NC-VMAT) by determining the table-angle and the gantry-angle ranges of the partial arcs through iterative 4π fluence map optimization (FMO) and beam direction elimination.

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. Electron arcs in mixed-beam radiotherapy (Arc-MBRT) consisting of intensity-modulated electron arcs with dynamic gantry rotation potentially reduce the delivery time compared to mixed-beam radiotherapy containing electron beams with static gantry angle (Static-MBRT). This study aims to develop and investigate a treatment planning process (TPP) for photon multileaf collimator (pMLC) based Arc-MBRT.

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Background: Exergames provide a promising new approach to implement simultaneous motor-cognitive training, which may support preventing the decline in cognitive functioning in older adults who have a mild neurocognitive disorder (mNCD).

Objectives: To evaluate feasibility, system usability, and acceptance of "Brain-IT", a newly developed training concept combining exergame-based motor-cognitive training and heart rate variability (HRV) guided resonance breathing for the secondary prevention of mNCD.

Methods: A pilot randomized controlled trial (RCT) with an allocation ratio of 2:1 (i.

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Non-coplanar radiotherapy treatment techniques on C-arm linear accelerators have the potential to reduce dose to organs-at-risk in comparison with coplanar treatment techniques. Accurately predicting possible collisions between gantry, table and patient during treatment planning is needed to ensure patient safety. We offer a freely available collision prediction tool using Blender, a free and open-source 3D computer graphics software toolset.

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Background: To improve organ at risk (OAR) sparing, dynamic trajectory radiotherapy (DTRT) extends VMAT by dynamic table and collimator rotation during beam-on. However, comprehensive investigations regarding the impact of the gantry-table (GT) rotation gradient on the DTRT plan quality have not been conducted.

Purpose: To investigate the impact of a user-defined GT rotation gradient on plan quality of DTRT plans in terms of dosimetric plan quality, dosimetric robustness, deliverability, and delivery time.

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Article Synopsis
  • External beam radiation therapy planning is complex, but machine-learning models, specifically 3D U-Nets, have been developed to predict dose distributions quickly and efficiently.
  • The study focused on training a 3D dose prediction model for glioblastoma (GBM) treatment using a dataset of 125 patients, where the model's robustness and sensitivity to contour variations were evaluated.
  • Results showed that the model achieved high accuracy in predicting dose distributions and effectively responded to contour changes, making it a valuable tool for enhancing quality assurance in radiation therapy planning.
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Background: Dynamic trajectory radiotherapy (DTRT) extends state-of-the-art volumetric modulated arc therapy (VMAT) by dynamic table and collimator rotations during beam-on. The effects of intrafraction motion during DTRT delivery are unknown, especially regarding the possible interplay between patient and machine motion with additional dynamic axes.

Purpose: To experimentally assess the technical feasibility and quantify the mechanical and dosimetric accuracy of respiratory gating during DTRT delivery.

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Introduction: Prior observational work in a heterogeneous cohort of participants with mild cognitive impairment suggests the Amsterdam Instrumental Activities of Daily Living Questionnaire (A-IADL-Q) may have greater sensitivity for functional decline than the more established Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL) scale. However, the relative utility of the A-IADL-Q versus the ADCS-ADL for clinical trials in early Alzheimer's disease (AD) remains uncertain.

Methods: We compared baseline and longitudinal performance of the A-IADL-Q and ADCS-ADL in participants with biomarker-confirmed prodromal (pAD;  = 158) or mild (mAD;  = 283) AD enrolled in the 18-month Tauriel study of semorinemab (NCT03289143).

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The growing nanoparticulate pollution (e.g. engineered nanoparticles (NPs) or nanoplastics) has been shown to pose potential threats to human health.

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