Predicting respiratory motion for real-time tumour tracking in radiotherapy

Purpose. Radiation therapy is a local treatment aimed at cells in and around a tumor. The goal of this study is to develop an algorithmic solution for predicting the position of a target in 3D in real time, aiming for the short fixed calibration time for each patient at the beginning of the procedure. Accurate predictions of lung tumor motion are expected to improve the precision of radiation treatment by controlling the position of a couch or a beam in order to compensate for respiratory motion during radiation treatment. Methods. For developing the algorithmic solution, data mining techniques are used. A model form from the family of exponential smoothing is assumed, and the model parameters are fitted by minimizing the absolute disposition error, and the fluctuations of the prediction signal (jitter). The predictive performance is evaluated retrospectively on clinical datasets capturing different behavior (being quiet, talking, laughing), and validated in real-time on a prototype system with respiratory motion imitation. Results. An algorithmic solution for respiratory motion prediction (called ExSmi) is designed. ExSmi achieves good accuracy of prediction (error $4-9$ mm/s) with acceptable jitter values (5-7 mm/s), as tested on out-of-sample data. The datasets, the code for algorithms and the experiments are openly available for research purposes on a dedicated website. Conclusions. The developed algorithmic solution performs well to be prototyped and deployed in applications of radiotherapy

IVUS-VH relation to the extent and composition of atherosclerotic plaque and clinical outcome prognosis

Background and aim: Most frequent and generally unpredictable coronary plaque rupture impacts the burden of coronary artery disease but features or signs related to plaque remodeling into the high risk structure are not clearly detectable by using ordinary visualization methods. Till yet there are no evident criteria for additional using IVUS. The aim of the study was to determinate intravascular ultrasound virtual histology (IVUS-VH) importance in identifying high risk plaques, which can contribute to increased rupture hazard. Methods: We selected 30 patients with stabile angina pectoris. 50 plaques were analyzed with coronary angiography digital assessment tool and IVUS similarly. Differences of stenoses measured by both methods, then were calculated and compared to composition of plaques evaluated by IVUS-VH. Results: Plaques were mostly formed of fibrous tissue (FI) (2.6 mm2; 57.89 %). Necrosis was found to make in average one-fifth of analyzed plaques (0.75 mm2, 19.60 %). Calcification made up the smallest part of plaques (0.3 mm2, 8.58 %). Plaques with higher necrosis component appeared to be significantly greater in IVUS compared to coronary angiography. In group A necrosis made up 1.40±1.05 mm2; group B – 0.87±0.52 mm2, and group C – 0.62 ±0.45 mm2 (p= 0.020). The same tendency was observed with FI: group A – 3.38±3.20 mm2; group B – 2.90±2.6 mm2 and group C – 2.04±165 mm2 (p= 0.082). Correlation analysis revealed negative moderate relationship between groups and necrosis percentage (r= –0.40, p= 0.004), and FI (r= –0.29, p= 0.039) components of the plaques. Conclusion: IVUS-VH provides new insight into the evaluation of different composition of plaques. However, despite the advantages, IVUS-VH remains costly and not always technically adaptive procedure, so it is necessary to pursue for new methods or technologies to identify atherosclerotic plaques at risk

Investigation of 5-Year Interconnections between Local Earth Magnetic Field Fluctuations and Acute Myocardial Infarction in Lithuania

The impact of the local Earth magnetic field (LEMF) on cardiovascular events has been studied recently. Data gathered during past years encouraged us to conduct this epidemiological analysis evaluating the association between changes in LEMF and hospital admissions due to AMI in Lithuania between August 2014 and September 2019. This study is unique due to its coverage of all Lithuanian patients. The frequency of morbidity of AMI was compared with the intensity of the LEMF and correlation coefficient was evaluated. The LEMF was measured by the Global Coherence Monitoring Network magnetometer located in Lithuania. LEMF was measured by pikotesla square (pT²). The LEMF was analized in five frequency ranges [Hz], generally called between Schumann resonance, which overlap with the human brain activity waves on electroencefalogram (EEG) frequency ranges (here, they are named as SDelta (0-3.5Hz), STheta (3.5-7Hz), SAlpha (7-15Hz), SBeta (15-32Hz) and SGamma (32-65Hz) to distinguish from the EEG bands). Significant correlations between weekly admissions of AMI cases and the weekly LEMF strength in five frequency ranges and in total range was found. A clear negative correlation was observed between cases of AMI in female group and LEMF frequency ranges SDelta (0-3.5Hz), STheta (3.5-7Hz), SAlpha (7-15Hz), SBeta (15-32Hz) and in total range. In the second half of the year the number of AMI is lower, therefore negative correlations between SDelta (0-3.5Hz), STheta (3.5-7Hz), SAlpha (7-15Hz) and SBeta (15-32Hz) ranges are stronger than in the first one. This is particularly noticeable in 2016 and 2018 years

Paediatric radiation therapy across Europe: A European questionnaire survey supported by the SIOPe, ESTRO, PROS and several national paediatric hematology-oncology societies (NAPHOS)

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RESEARCH Open Access Preparedness of Lithuanian general practitioners

to provide mental healthcare services: a cross-sectional surve

Round-Trip Delay Estimation in OPC UA Server-Client Communication Channel

In this paper an estimation of round-trip delay (RTD) in OPC UA server-client channel was investigated in various data communication networks including Ethernet, WiFi, and 3G. Testing was carried out using the developed IoT gateway device running OPC UA server and remote computer running OPC UA client. The server and the client machines were configured to operate in Virtual Private Network powered by OpenVPN. Experimental analysis revealed that RTD values are distributed in the wide range exhibiting difficult-to-explain outliers significantly exceeding average RTD value. A preliminary exploration of the correlation between instantaneous load of communication gateway processor and RTD peaks was carried out on ARM Cortex A8 Texas instruments processors running at 600 MHz and 800 MHz clock frequency

Enabling factors for antibiotic prescribing for upper respiratory tract infections:Perspectives of Lithuanian and Russian general practitioners

INTRODUCTION: General practitioners (GPs) write about 80% of all antibiotic prescriptions, the greatest number of them for patients with respiratory tract infections. However, there is a lack of research targeting the influence of external factors on antibiotic prescribing by physicians. This study aimed to explore experiences of GPs in Lithuania and the Russian Federation with regard to antibiotic prescription for upper respiratory tract infections. By such means it might be possible to reveal external enabling factors that influence antibiotic prescribing in these countries. METHOD: Five focus groups were performed with 22 GPs from Lithuania and 29 GPs from the Kaliningrad Region of the Russian Federation; then, thematic analysis of data was performed. RESULTS: Six thematic categories were identified that are related to external forces enabling antibiotic prescription: the necessity for political leadership to encourage clinically grounded antibiotic use; over-the-counter sale of antibiotics; designation of antibiotics as reimbursable medications; supervision by external oversight institutions; lack of guidelines for the treatment of upper respiratory tract infections; and pharmaceutical company activities. CONCLUSIONS: Comprehensive efforts to reduce the burden of non-clinically grounded antibiotic prescription should go beyond addressing factors at the physician–patient level and take into account important factors in the enabling environment as well