Simulation of the Neutral Particle Converter of the ARIES-L Device

AbstractThis paper presents the concept of Lunar regolith surface layer composition analysis using solar wind bombardment and registration of the sputtered and knocked out atoms converted into ions with solid-state converters and subsequent registration of ions by high-aperture electrostatic analyzer. Monte Carlo binary collision approximation code is used to calculate angular and energy distributions of scattered and sputtered atoms. Literature data are used for evaluation of charged fractions of scattered and sputtered components and SIMION code is used for calculation of charged particles trajectories in electrostatic deflector. The total sensitivity of the proposed scheme is evaluated

Surgical correction of distal tibia posttraumatic deflection

Abstract Objective – to study the issues related to diagnostics and treatment of pilon fracture of the tibial epiphysis and individual approach to surgical correction of posttraumatic deformations of the distal tibia. Material and methods. The treatment results of 49 patients who had suffered pilon fractures throughout 1–2 years after treatment completion were studied in the clinic of Traumatology and Orthopedic on the basis of “ZSMKH №9”. According to the AO classification patients had the following types of fractures: 43A – 7 patients, 43B – 14 and43C – 28. The X-ray measurements characterizing the geometric shape of articular surfaces were measured. The mathematical finite element method of computer modeling was used for the study of bone and cartilaginous tissues stress distribution pattern in the ankle joint in its normal condition and in case of post-traumatic deflections. Results. The basic pathological symptom in patients with pilon fractures of distal tibia is joint function limitation, which spreads to the sector of dorsal extension, regardless of the pilon fracture type. The joint continues to function, however movement amplitude is decreased. The most unfavorable change of distal tibia shape is valgus inclination of articular surface. This configuration change of tibial articular end requires repeated surgical correction. Conclusions. The main task of the distal tibial epiphysis surgical correction is the weight-bearing function and axial relationships restoration and pain management. It can be concluded that selective approach to posttraumatic deformations of the distal tibia surgical correction is essential. The main indications for surgical correction are pseudarthrosis, deviations in the frontal plane of more than 10 degrees, severe joint arthrosis accompanied by pain syndrome for more than a year

MAGNETIC RESONANCE SEMIOTICS OF BREAST CANCER

Breast cancer (BC) that is the most common malignancy in women presents an indubitable threat to their life and health. The basis for this investigation was magnetic resonance imaging (MRI) data of 203 women with histologically verified malignan- cies. The patients' mean age was 53±10.2 years. The paper describes the magnetic resonance semiotics of BC; the authors have developed criteria for dynamic contrast-enhanced magnetic resonance mammography used in the differential diagnosis of nodules.Due to high soft-tissue contrast, the use of thin sections, and the possibility of examining in any projection, MRI allows one not only to accurately visualize a pathological mass as compared with X-ray mammography or ultrasound study, but also to characterize its vascularization, which is a major criteria for the differential diagnosis of benign and malignant breast nodules

Temporal response to harmonic driving in electroconvection

The temporal evolution of the spatially periodic electroconvection (EC) patterns has been studied within the period of the driving ac voltage by monitoring the light intensity diffracted from the pattern. Measurements have been carried out on a variety of nematic systems, including those with negative dielectric and positive conductivity anisotropy, exhibiting "standard EC" (s-EC), those with both anisotropies negative exhibiting "non-standard EC" (ns-EC), as well as those with the two anisotropies positive. Theoretical predictions have been confirmed for stationary s-EC and ns-EC patterns. Transitions with Hopf bifurcation have also been studied. While traveling had no effect on the temporal evolution of dielectric s-EC, traveling conductive s-EC and ns-EC patterns exhibited a substantially altered temporal behavior with a dependence on the Hopf frequency. It has also been shown that in nematics with both anisotropies positive, the pattern develops and decays within an interval much shorter than the period, even at relatively large driving frequencies.Comment: 19 pages, 5 figure

Оптимизация протокола сканирования при динамическом наблюдении женщин со злокачественными новообразованиями органов таза

Introduction. MRI is widely used to follow-up malignant neoplasms of the female pelvis. Aim. To optimize the use of MRI sequences for follow-up of female patients with malignant pelvic neoplasms. Materials and methods. Retrospective analysis of female pelvic MRI has been performed on 1.5 T MR scanner. This study includes 530 protocols. Results. The authors describe different protocols for assessment and differential diagnosis of recurrence, postradiation and postoperative changes. It includes applicable sequences, axis and the structure which require evaluation. In all cases, dynamic follow-up has to include analysis of patient's previous studies, anamnesis, previous treatment, as well as the end of chemotherapy and radiotherapy. All of the above, combined with the oncologist's treatment of choice determines the objective of this study. Nowadays, MRI is the method which most accurately characterizes postoperative and postradiation structural changes. MRI is useful in detection of pelvic lymph nodes. The role of MRI has high potential in assessing the effectiveness of chemotherapy and radiation therapy. Conclusion. In order to make the optimal scan protocol, follow-up of malignant neoplasms of the pelvic organs in women require the use of clinical and anamnestic data along with the results of patient's previous studies. The combined use of various sequences and techniques can improve the diagnostic significance of pelvic MRI at follow-up. Contrast enhancement has additional role in diagnostics of recurrent of pelvic organs in women. The use of different contrast enhancement techniques has proven effective in case of postradiation and postoperative complications.Введение. Магнитно-резонансное исследование (МРТ) широко используется при наблюдении после проведенного лечения у пациенток с неоплазиями таза. Цель исследования: достичь целевого использования МРТ-последовательностей у пациенток со злокачественными новообразованиями органов таза после различных видов лечения. Материалы и методы. Ретроспективный анализ МРТ-исследований с различной патологией органов таза у женщин. В исследование включено 530 исследований. Результаты. В работе описаны различные протоколы МРТ-сканирования для оценки и дифференциальной диагностики рецидива, постлучевых и послеоперационных изменений. Обсуждены необходимые взвешенности, направление срезов, а также структуры, требующие оценки. При динамическом наблюдении во всех случаях необходимо анализировать данные предыдущих исследований, данные анамнеза, вид примененного лечения, также важно оценивать сроки окончания химиотерапии и лучевой терапии. Вся эта информация в совокупности с направлением онколога и определяет цель исследования. МРТ на данный момент является методом, наиболее точно характеризующим послеоперационные и постлучевые структурные изменения. МРТ играет ключевую роль в поиске тазовых лимфатических узлов, перспективна в оценке эффективности химиотерапии и лучевой терапии. Заключение. При динамическом исследовании злокачественных новообразований органов таза у женщин для оптимизации времени его проведения и повышения оказания качества медицинской помощи важно опираться на данные анамнеза, принимать во внимание результаты предыдущих исследований. Целевое использование возможностей МРТ позволяет более детально и точно высказываться о патологии органов таза у женщин при оценке изменений в динамике после лечения. Контрастирование имеет вспомогательное значение при диагностике рецидива злокачественных новообразований органов таза у женщин. Применение различных методик контрастирования обосновано в случае постлучевых и послеоперационных осложнений при лечении злокачественных новообразований органов таза у женщин

СРАВНЕНИЕ РАЗЛИЧНЫХ ПОДХОДОВ К ОЦЕНКЕ ДИАГНОСТИЧЕСКОГО КАЧЕСТВА КОМПЬЮТЕРНОЙ ТОМОГРАФИИ ОРГАНОВ ГРУДНОЙ КЛЕТКИ

The aim of the current study was to assess the physical and technical image quality parameters of the CT images obtained on low-dose chest protocols.Materials and methods. The study was performed using the ACR CT PHANTOM on the Philips Ingenuity 128 CT unit. The following parameters were selected for the assessment of image quality: Hounsfield unit accuracy, image noise, contrast to noise ratio and spatial resolution.The results of the study indicate the lack of significant differences between the selected low-dose protocols.  Additionally, the correlation between the results of the assessment of physical and technical parameters of CT  images and expert image quality evaluation was weak. That does not allow implementing the low-dose protocols  into clinical practice based solely on the assessment of the physical and technical parameters.Целью данной работы являлась оценка физико-технических параметров качества КТ-изображений, выполненных на низкодозовых протоколах сканирования органов грудной клетки.Материалы и методы. Работа выполнена с использованием фантома ACR CT PHANTOM для компьютерного томографа Philips Ingenuity 128. Оценка качества изображения  осуществлялась по точности определения единиц Хаунсфилда, шума изображения, отношения контраста к шуму и пространственного разрешения.Результаты исследования показали, отсутствие достоверных различий между различными низкодозовыми протоколами. При этом наблюдалась слабая корреляция между результатами физико-технических параметров изображения и экспертной оценки качества изображения, что не позволяет принимать решение о внедрении низкодозовых протоколов в практику, основываясь только на оценке физико-технических параметров

Evaluation of fetal absorbed doses from computed tomography examinations of pregnant patients: A systematic review

BACKGROUND: Currently, no systematic data are available on fetal radiation exposure as a result of radiographic studies during pregnancy. Consequently, there are no approved methods of its calculation that can be used in clinical practice. It is especially relevant for computed tomography scans as it is a widely used and highly informative method of diagnostic imaging associated with high exposure levels. AIM: to systematize currently available data on radiation dose absorbed by the fetus from computed tomography scans in pregnant women. MATERIALS AND METHODS: The search for publications in Russian and English was conducted in PubMed/Medline, Google Scholar and еLibrary. The final analysis included 12 papers including 8 studies using human body phantoms, 3 retrospective studies and one prospective clinical study. RESULTS: Abdominal and pelvic computed tomography scans as well as whole-body scans were found to be associated with the highest fetal radiation exposure. However, in none of the publications the fetal exposure limit was exceeded. CONCLUSION: Clinically indicated non-contrast-enhanced computed tomography scans in pregnant women are not likely to be associated with the fetal absorbed doses that exceed the limit of 100 mGy regardless of the scanned area. However, this limit might be exceeded in case of performing multiple studies or if multiphase abdominal or pelvic computed tomography scans, or whole-body computed tomography scans are performed in patients with multiple trauma. In these cases, a decision regarding the need for these investigations should be made by a multi-disciplinary team (including radiation safety specialists, diagnostic radiologists and clinicians) based on the results of additional risk assessment

Оценка влияния сопутствующей глаукомы на результаты эндотелиальной кератопластики при буллезной кератопатии

PURPOSE: Evaluate the influence of concomitant glaucoma on the ultra-thin Descemet’s stripping automated endothelial keratoplasty (UTDSAEK) outcome. METHODS: 64 patients (67 eyes) with bullous keratopathy underwent UTDSAEK. The average age of the patients was 71.7±5.4 years. The average preoperative visual acuity equaled 0.04±0.04. 19 patients (19 eyes) had a history of glaucoma (stages II-III). 45 patients (48 eyes) didn’t have glaucoma. Bullous keratopathy was detected in 47 of the studied eyes, Fuchs dystrophy - in 20. Prior to the operation mean intraocular pressure (Р0) in eyes with glaucoma was 13±2.3 mmHg, in eyes without glaucoma - 14±3.1 mmHg. Intraocular pressure before and after the operation was measured by Tonopen-XL tonometer. RESULTS: In 1 year after endothelial keratoplasty mean IOP for patients with concomitant glaucoma was higher than before surgery and equaled 16±2.8 mmHg (pЦЕЛЬ. Оценить влияние сопутствующей глаукомы на результаты автоматизированной эндотелиальной кератопластики с удалением десцеметовой мембраны и использованием тонких трансплантатов (UTDSAEK). МЕТОДЫ. 64 пациентам (67 глаз) с буллезной кератопатией произвели UTDSAEK. Средний возраст пациентов составил 71,7±5,4 года. Средняя дооперационная острота зрения равнялась 0,04±0,04. Не страдали глаукомой 45 больных (48 глаз), у 19 пациентов (19 глаз) в анамнезе имелась глаукома II-III стадии. Вторичная буллезная кератопатия была выявлена на 47 глазах, дистрофия Фукса - на 20. Среднее внутриглазное давление (ВГД, Р0) на глазах с глаукомой до кератопластики составляло 13±2,3 мм рт.ст., на глазах без глаукомы - 14±3,1 мм рт.ст. ВГД до и после операции измеряли апланационным тонометром Tonopen-XL. РЕЗУЛЬТАТЫ. Через 1 год после эндотелиальной кератопластики среднее ВГД у больных с сопутствующей глаукомой было достоверно выше, чем до операции, и равнялось 16±2,8 мм рт.ст. (

Evaluation of myocardial damage in different types of rheumatoid arthritisduring disease-modifying antirheumatic drug or biological therapy (with infliximab)

Objective. To estimate the extent and pattern of myocardial damage in different types of rheumatoid arthritis (RA) during disease-modifying antirheumatic drug (DMARD) or biological therapy. Subjects and methods. Seventy-one patients with RA were examined; some of them received biological therapy with infliximab, while the others took DMARDs. A group of patients with incipient RA was also identified. B-type brain natriuretic peptide levels were estimated and electrocardiography, echocardiography (EchoCG), and cardiac magnetic resonance imaging (MRT) using the contrast medium Dotarem were conducted in all the patients. The follow-up totaled 6 months. A control examination was made at the moment of randomization and 6 months posttreatment. Results. Tn the bulk of patients, the level of B-type brain natriuretic peptide did not differ from the reference values, however, its lower level was observed in the incipient RA group, which was associated with the absence of cardiovascular diseases and with a younger age group. There were no negative EchoCG changes in myocardial viability values. Cardiac MRT demonstrated that the majority of patients had the similar changes that failed to affect myocardial kinetics and ejection fraction. These changes were not found in incipient RA patients without cardiovascular diseases. No improvement in myocardial viability was recorded in the patients receiving the biological therapy. Conclusion. Thus, cardiac MRT showed the similar changes that failed to affect myocardial kinetics and ejection fraction in patients with RA during both methotrexate and infliximab therapy