Explore the vast range of titles available.

BackgroundSmall Animal Fast Insert for MRI detector I (SAFIR-I) is a novel Positron Emission Tomography insert for a 7T Bruker BioSpec 70/30 Ultra Shield Refrigerated Magnetic Resonance Imaging (MRI) system. It facilitates truly simultaneous quantitative imaging in mice and rats at injected activities as high as 500MBq. Exploitation of the resulting high count rates enables quick image formation at few seconds per frame. In this investigation, key performance parameters of SAFIR-I have been determined according to the evaluations outlined in the National Electrical Manufacturers Association (NEMA) Standards Publication NU 4-2008 (NEMA-NU4) protocol.ResultsUsing an energy window of 391 to 601keV and a Coincidence Timing Window of 500ps, the following performance was observed: The average spatial resolution at 5mm radial offset (Full Width at Half Maximum) is 2.54mm when using Filtered Backprojection, 3D Reprojection reconstruction. For the mouse- and rat-like phantoms, the maximal Noise-Equivalent Count Rates (NECRs) are 1368kcps at the highest tested average effective concentration of 14.7MBqcc-1, and 713kcps at the highest tested average effective concentration of 1.72MBqcc-1, respectively. The NECR peak is not yet reached for either of these cases. The peak sensitivity is 1.46%. The Image Quality phantom uniformity standard deviation is 4.8%. The Recovery Coefficient for the 5mm rod is (1.08±0.10). The Spill-Over Ratios are (0.22±0.03) and (0.22±0.02), for the water- and air-filled cylinder, respectively. An accuracy of 4.3% was achieved for the quantitative calibration of reconstructed voxel values.ConclusionsThe measured performance parameters indicate that the various design goals have been achieved. SAFIR-I offers excellent performance, especially at the high activities it was designed for. This facilitates planned experiments with fast tracer kinetics in small animals. Ways to potentially improve performance can still be explored. Simultaneously, further performance gains can be expected for a forthcoming insert featuring 2.7 times longer axial coverage named Small Animal Fast Insert for MRI detector II (SAFIR-II).

(1) Background: Small Animal Fast Insert for MRI detector I (SAFIR-I) is a preclinical Positron Emission Tomography (PET) insert for the Bruker BioSpec 70/30 Ultra Shield Refrigerated (USR) preclinical 7T Magnetic Resonance Imaging (MRI) system. It is designed explicitly for high-rate kinetic studies in mice and rats with injected activities reaching 500MBq, enabling truly simultaneous quantitative PET and Magnetic Resonance (MR) imaging with time frames of a few seconds in length. (2) Methods: SAFIR-I has an axial field of view of 54.2mm and an inner diameter of 114mm. It employs Lutetium Yttrium OxyorthoSilicate (LYSO) crystals and Multi Pixel Photon Counter (MPPC) arrays. The Position-Energy-Timing Application Specific Integrated Circuit, version 6, Single Ended (PETA6SE) digitizes the MPPC signals and provides time stamps and energy information. (3) Results: SAFIR-I is MR-compatible. The system’s Coincidence Resolving Time (CRT) and energy resolution are between separate-uncertainty 209.0(3)ps and separate-uncertainty 12.41(02) Full Width at Half Maximum (FWHM) at low activity and separate-uncertainty 326.89(12)ps and separate-uncertainty 20.630(011) FWHM at 550MBq, respectively. The peak sensitivity is ∼1.6. The excellent performance facilitated the successful execution of first in vivo rat studies beyond 300MBq. Based on features visible in the acquired images, we estimate the spatial resolution to be ∼2mm in the center of the Field Of View (FOV). (4) Conclusion: The SAFIR-I PET insert provides excellent performance, permitting simultaneous in vivo small animal PET/MR image acquisitions with time frames of a few seconds in length at activities of up to 500MBq.

TNF-related apoptosis-inducing ligand (TRAIL) receptor 2 (TRAIL-R2) can induce apoptosis in cancer cells upon crosslinking by TRAIL. However, TRAIL-R2 is highly expressed by many cancers suggesting pro-tumor functions. Indeed, TRAIL/TRAIL-R2 also activate pro-inflammatory pathways enhancing tumor cell invasion, migration, and proliferation. In addition, nuclear TRAIL-R2 (nTRAIL-R2) promotes malignancy by inhibiting miRNA let-7-maturation. Here, we show that TRAIL-R2 interacts with the tumor suppressor protein p53 in the nucleus, assigning a novel pro-tumor function to TRAIL-R2. Knockdown of TRAIL-R2 in p53 wild-type cells increases the half-life of p53 and the expression of its target genes, whereas its re-expression decreases p53 protein levels. Interestingly, TRAIL-R2 also interacts with promyelocytic leukemia protein (PML), a major regulator of p53 stability. PML-nuclear bodies are also the main sites of TRAIL-R2/p53 co-localization. Notably, knockdown or destruction of PML abolishes the TRAIL-R2-mediated regulation of p53 levels. In summary, our finding that nTRAIL-R2 facilitates p53 degradation and thereby negatively regulates p53 target gene expression provides insight into an oncogenic role of TRAIL-R2 in tumorigenesis that particularly manifests in p53 wild-type tumors.

Spiking neural networks (SNN) hold the promise of being a more biologically plausible, low-energy alternative to conventional artificial neural networks. Their time-variant nature makes them particularly suitable for processing time-resolved, sparse binary data. In this paper, we investigate the potential of leveraging SNNs for the detection of photon coincidences in positron emission tomography (PET) data. PET is a medical imaging technique based on injecting a patient with a radioactive tracer and detecting the emitted photons. One central post-processing task for inferring an image of the tracer distribution is the filtering of invalid hits occurring due to e.g. absorption or scattering processes. Our approach, coined PETNet, interprets the detector hits as a binary-valued spike train and learns to identify photon coincidence pairs in a supervised manner. We introduce a dedicated multi-objective loss function and demonstrate the effects of explicitly modeling the detector geometry on simulation data for two use-cases. Our results show that PETNet can outperform the state-of-the-art classical algorithm with a maximal coincidence detection \\(F_1\\) of 95.2%. At the same time, PETNet is able to predict photon coincidences up to 36 times faster than the classical approach, highlighting the great potential of SNNs in particle physics applications.

Ion-beam radiotherapy is an advanced cancer treatment modality offering steep dose gradients and a high biological effectiveness. These gradients make the therapy vulnerable to patient-setup and anatomical changes between treatment fractions, which may go unnoticed. Charged fragments from nuclear interactions of the ion beam with the patient tissue may carry information about the treatment quality. Currently, the fragments escape the patient undetected. Inter-fractional in-vivo treatment monitoring based on these charged nuclear fragments could make ion-beam therapy safer and more efficient. We developed an ion-beam monitoring system based on 28 hybrid silicon pixel detectors (Timepix3) to measure the distribution of fragment origins in three dimensions. The system design choices as well as the ion-beam monitoring performance measurements are presented in this manuscript. A spatial resolution of 4 mm along the beam axis was achieved for the measurement of individual fragment origins. Beam-range shifts of 1.5 mm were identified in a clinically realistic treatment scenario with an anthropomorphic head phantom. The monitoring system is currently being used in a prospective clinical trial at the Heidelberg Ion Beam Therapy Centre for head-and-neck as well as central nervous system cancer patients.

Head and neck (HN) tumors are responsible for approximately 4% of annual new cancer cases worldwide. Besides surgery, radiochemotherapy, particularly fractionated radiotherapy (RT), is the gold-standard treatment modality for these cancers. However, there is currently no reliable early measure of success available to further personalize treatment plans. This work aims to address this critical bottleneck by pioneering the use of photoacoustic imaging (PAI) to measure treatment response in HN cancer patients undergoing RT. PAI leverages the photoacoustic effect in order to non-invasively recover functional tissue properties in depths of up to several centimeters. We hypothesized that oxygen saturation ( ), hemoglobin concentration, and water content, as measured by PAI, would non-invasively reflect expected RT treatment effects, namely reoxygenation of lymph nodes (hypothesis H1), inflammation of surrounding organs (H2) and xerostomia (H3). Our study with n = 30 human subjects showed notable changes in , hemoglobin concentration, and water levels in HN tumor patients resulting from disease treatment. Our data confirmed hypotheses H2 and H3, while an observed decrease in over the treatment course contradicted our prior assumptions (H1). A comprehensive analysis based on device and tissue digital twins, however, revealed that low blood volume fraction as encountered in malignant nodes, can lead to particularly high prediction errors, indicating that the measured values cannot be trusted within these regions. We conclude that our study is the first to show that PAI is capable of measuring early molecular changes induced by RT in human tissue non-invasively. Further studies are now needed to convert the potential of the new imaging technique into patient benefit.

Background Heparin is used worldwide for 70 years during all non-cardiac arterial procedures (NCAP) to reduce thrombo-embolic complications (TEC). But heparin also increases blood loss causing possible harm for the patient. Heparin has an unpredictable effect in the individual patient. The activated clotting time (ACT) can measure the effect of heparin. Currently, this ACT is not measured during NCAP as the standard of care, contrary to during cardiac interventions, open and endovascular. A RCT will evaluate if ACT-guided heparinization results in less TEC than the current standard: a single bolus of 5000 IU of heparin and no measurements at all. A goal ACT of 200–220 s should be reached during ACT-guided heparinization and this should decrease (mortality caused by) TEC, while not increasing major bleeding complications. This RCT will be executed during open abdominal aortic aneurysm (AAA) surgery, as this is a standardized procedure throughout Europe. Methods Seven hundred fifty patients, who will undergo open AAA repair of an aneurysm originating below the superior mesenteric artery, will be randomised in 2 treatment arms: 5000 IU of heparin and no ACT measurements and no additional doses of heparin, or a protocol of 100 IU/kg bolus of heparin and ACT measurements after 5 min, and then every 30 min. The goal ACT is 200–220 s. If the ACT after 5 min is < 180 s, 60 IU/kg will be administered; if the ACT is between 180 and 200 s, 30 IU/kg. If the ACT is > 220 s, no extra heparin is given, and the ACT is measured after 30 min and then the same protocol is applied. The expected incidence for the combined endpoint of TEC and mortality is 19% for the 5000 IU group and 11% for the ACT-guided group. Discussion The ACTION-1 trial is an international RCT during open AAA surgery, designed to show superiority of ACT-guided heparinization compared to the current standard of a single bolus of 5000 IU of heparin. A significant reduction in TEC and mortality, without more major bleeding complications, must be proven with a relevant economic benefit. Trial registration {2a} NTR NL8421 ClinicalTrials.gov NCT04061798 . Registered on 20 August 2019 EudraCT 2018-003393-27 Trial registration: data set {2b} Data category Information Primary registry and trial identifying number ClinicalTrials.gov : NCT04061798 Date of registration in primary registry 20-08-2019 Secondary identifying numbers NTR: NL8421 EudraCT: 2018-003393-27 Source(s) of monetary or material support ZonMw: The Netherlands Organisation for Health Research and Development Dijklander Ziekenhuis Amsterdam UMC Primary sponsor Dijklander Ziekenhuis Secondary sponsor(s) N/A Contact for public queries A.M. Wiersema, MD, PhD Arno@wiersema.nu 0031-229 208 206 Contact for scientific queries A.M. Wiersema, MD, PhD Arno@wiersema.nu 0031-229 208 206 Public title ACT Guided Heparinization During Open Abdominal Aortic Aneurysm Repair (ACTION-1) Scientific title ACTION-1: ACT Guided Heparinization During Open Abdominal Aortic Aneurysm Repair, a Randomised Trial Countries of recruitment The Netherlands. Soon the recruitment will start in Germany Health condition(s) or problem(s) studied Abdominal aortic aneurysm, arterial disease, surgery Intervention(s) ACT-guided heparinization 5000 IU of heparin Key inclusion and exclusion criteria Ages eligible for the study: ≥18 years Sexes eligible for the study: both Accepts healthy volunteers: no Inclusion criteria: Study type Interventional Allocation: randomized Intervention model: parallel assignment Masking: single blind (patient) Primary purpose: treatment Phase IV Date of first enrolment March 2020 Target sample size 750 Recruitment status Recruiting Primary outcome(s) The primary efficacy endpoint is 30-day mortality and in-hospital mortality during the same admission. The primary safety endpoint is the incidence of bleeding complications according to E-CABG classification, grade 1 and higher. Key secondary outcomes Serious complications as depicted in the Suggested Standards for Reports on Aneurysmal disease: all complications requiring re-operation, longer hospital stay, all complications

Background Stereotactic Body Radiotherapy (SBRT) is a standard treatment for inoperable primary and secondary lung tumors. In case of ultracentral tumor location, defined as tumor contact with vulnerable mediastinal structures such as the proximal bronchial tree (PBT) or esophagus, SBRT is associated with an increased risk for severe complications. Magnetic resonance (MR)-guided SBRT can mitigate this risk based on gated dose delivery and daily plan adaptation. The MAGELLAN trial aims to find the maximum tolerated dose (MTD) of MR-guided SBRT of ultracentral lung tumors (ULT). Patients and methods MAGELLAN is a prospective phase I dose escalation trial. A maximum of 38 patients with primary and secondary ULT with a tumor size ≤ 5 cm will be enrolled. Ultracentral location is defined as an overlap of the planning target volume (PTV) with the PBT or esophagus. Patients are treated at a 0.35 Tesla MR-linac (MRIdian® Linac, ViewRay Inc. ) employing a gating strategy and daily plan adaptation. Dose escalation starts at 10 × 5.5 Gy (biologically effective dose BED 3/10 : 155.83 Gy/85.25 Gy), may proceed up to 10 × 6.5 Gy (BED 3/10 : 205.83 Gy/107.25 Gy) and is guided by a customized time-to-event continual reassessment method (TITE CRM) with backup element, which alternately assigns patients to dose escalation and backup cohorts. Discussion The results of the MAGELLAN trial will guide further research and clinical implementation of MR-guided SBRT as ablative treatment of ULT. Moreover, the combination of MR-guided radiotherapy with TITE-CRM including a backup element may serve as blueprint for future radiation dose escalation studies in critical locations. Trial Registration Registered at ClinicalTrials.gov: NCT04925583 on 14th June 2021.

Introduction The APROVE-trial investigated the tolerability of postoperative proton beam therapy in women with cervical or endometrial cancer. The present analysis evaluated the secondary endpoints of health-related quality of life (HRQOL) and patient-reported symptoms. Methods 25 patients were included in this prospective phase-II-trial and treated with postoperative radiotherapy using protons alone or in combination with chemotherapy. To attain general and gynecologic-specific HRQOL measures, the EORTC-QLQ-C30 questionnaires combined with -QLQ-CX24 for cervical and -QLQ-EN24 for endometrial cancer were assessed at baseline, at the end of RT and up to 2 years after radiotherapy. The results were compared to an age-matched norm reference population. Symptoms were assessed using Common Terminology Criteria for Adverse Events (CTCAE) and institutional patient-reported symptoms grading. Results Scores regarding global health status were markedly impaired at baseline (mean: 58.0 ± 20.1) compared to reference population data, but significantly ( p  = 0.036) improved and evened out to comparable norm values 2 years after proton therapy (mean: 69.9 ± 19.3). Treatment caused acute and long-term worsening of pain ( p  = 0.048) and gastrointestinal symptoms ( p  = 0.016) for women with endometrial cancer, but no higher-grade CTCAE ≥ 3° toxicity was observed. Dosimetric evaluation of rectum, sigmoid, large and small bowel showed no correlation with the reported gastrointestinal symptoms. After 2 years, fatigue had significantly improved ( p  = 0.030), whereas patients with cervical cancer experienced more often lymphedema ( p  = 0.017). Scores for endometrial cancer pertaining to sexual activity ( p  = 0.048) and body image ( p  = 0.022) had improved post treatment; in the latter this effect persisted after 2 years. Conclusion Proton beam therapy in the adjuvant setting was well tolerated with only low-grade side effects concerning gastrointestinal symptoms, lymphedema and pain. Overall quality of life was impaired at baseline, but patients were able to recover to values comparable to norm population 2 years after proton therapy. Larger studies are needed to confirm whether the benefit of proton therapy translates into a clinical effect. Sexual dysfunction remains an important issue. Trial registration : The trial was registered at https://clinicaltrials.gov (ClinicalTrials.gov Identifier: NCT03184350, 09th June 2017).

Background Cardiac arrhythmia has been reported as a significant complication of thoracic radiotherapy. Both bradyarrhythmias and tachyarrhythmias have been reported, highlighting the arrhythmia-modulating potential of radiation in certain oncologic therapies. This study aimed to analyse the arrhythmic burden in patients with cardiac implantable electrical devices (CIEDs) undergoing thoracic irradiation, examining both immediate effects of radiotherapy and long-term sequelae post-therapy. Methods and results A retrospective cohort study was conducted involving patients with CIEDs who received thoracic radiotherapy between January 2012 and December 2022. Two distinct analyses were performed involving (1) daily CIED follow-ups during radiotherapy and (2) long-term arrhythmic outcomes post-therapy. For long-term outcomes, Patients were matched in a 1:2 ratio with non-irradiated controls based on age, sex, cardiovascular risk factors, cardiac disease, and beta-blocker use. Statistical analyses included negative binomial regression and propensity score matching. A total of 186 patients underwent daily CIED monitoring during radiotherapy, with 79 receiving thoracic irradiation. Thoracic irradiation was negatively associated with atrial arrhythmia (OR 0.11 [0.02;0.70, 95% CI], adjusted p  = 0.0498) and there was a tendency towards less ventricular events (OR 0.14 [0.02;1.41, 95% CI], adjusted p  = 0.3572) during radiotherapy in a univariate regression analysis. This association was not significant in the multivariate (OR 0.44 [0.10;1.80, 95%-CI], p  = 0.16) model including a history of atrial fibrillation, diabetes and beta-blocker use. Coronary artery disease was associated with an increase in atrial and ventricular arrhythmia. For the long-term analysis, 122 patients were followed up after thoracic ( N  = 33) and non-thoracic radiation ( N  = 89) and compared to 244 matched controls drawn from approximately 10.000 CIED-patients. There was no significant increase in arrhythmic events compared to controls over a median follow-up of 6.6 months. A previous history of ventricular or atrial arrhythmic events was the strongest predictor for events during the follow-up. Conclusion Thoracic radiotherapy can be safely administered in patients with CIEDs. However, patients with a history of arrhythmia are more prone to arrhythmic events during and after radiation. These findings highlight the need for personalized arrhythmia management strategies and further research to understand the mechanisms underlying the antiarrhythmic effects of thoracic radiation. Graphical Abstract