Diagnostic Setup Research Articles

An MRI comparative image evaluation under diagnostic and radiotherapy planning set-ups using a carbon fibre tabletop for pelvic radiotherapy

PurposeTo quantitatively and qualitatively evaluate and compare MR images acquired from the usual diagnostic set-up with images acquired in a radiotherapy set-up. Materials and methodsMR images of a phantom and 18 prostate cancer patients imaging using the usual diagnostic set-up with a curved tabletop (DX-set-up) and using a radiotherapy set-up (RT-set-up) with a flat tabletop, were analysed retrospectively. Quantitative assessments were made by measuring signal-to-noise ratio (SNR) and contrast to noise ratio (CNR). Non-parametric tests were used. Qualitative assessments were made independently by three radiologists. Inter-rater reliability was measured as the percentage of agreement and Gwet's AC2 test. ResultsThe use of the RT-set-up was linked to 19.3% SNR drop on the phantom image. Up to 24% SNR prostate drop was observed in patients’ images. Up to 34% CNR drop was observed in patients’ images. Although image quality of the RT-set-up was acceptable, all measured domains were worse than the corresponding DX-set-up. Additionally diagnostic images were linked to a better percentage of agreement among raters. ConclusionsSNR, CNR and image quality were significantly worse when using the RT-set-up than with the DX-set-up although Image quality in the RT-set-up was acceptable.

Characterization of a Bayesian network-based radiotherapy plan verification model.

The current process for radiotherapy treatment plan quality assurance relies on human inspection of treatment plans, which is time-consuming, error prone and oft reliant on inconsistently applied professional judgments. A previous proof-of-principle paper describes the use of a Bayesian network (BN) to aid in this process. This work studied how such a BN could be expanded and trained to better represent clinical practice. We obtained 51540 unique radiotherapy cases including diagnostic, prescription, plan/beam, and therapy setup factors from a de-identified Elekta oncology information system from the years 2010-2017 from a single institution. Using a knowledge base derived from clinical experience, factors were coordinated into a 29-node, 40-edge BN representing dependencies among the variables. Conditional probabilities were machine learned using expectation maximization module using all data except a subset of 500 patient cases withheld for testing. Different classes of errors that were obtained from incident learning systems were introduced to the testing set of cases which were withheld from the dataset used for building the BN. Different sizes of datasets were used to train the network. In addition, the BN was trained using data from different length epochs as well as different eras. Its performance under these different conditions was evaluated by means of Areas Under the receiver operating characteristic Curve (AUC). Our performance analysis found AUCs of 0.82, 0.85, 0.89, and 0.88 in networks trained with 2-yr, 3-yr 4-yr and 5-yr windows. With a 4-yr sliding window, we found AUC reduction of 3% per year when moving the window back in time in 1-yr steps. Compared to the 4-yr window moved back by 4yrs (2010-2013 vs 2014-2017), the largest component of overall reduction in AUC over time was from the loss of detection performance in plan/beam error types. The expanded BN method demonstrates the ability to detect classes of errors commonly encountered in radiotherapy planning. The results suggest that a 4-yr training dataset optimizes the performance of the network in this institutional dataset, and that yearly updates are sufficient to capture the evolution of clinical practice and maintain fidelity.

Laser-Induced Desorption of co-deposited Deuterium in Beryllium Layers on Tungsten

Abstract For the development of the tritium monitoring system in ITER the hydrogen isotope release by Laser-Induced Desorption (LID) from Be layers is studied to determine the laser parameters for a high desorption efficiency while minimising dust production and surface modifications is also pursued. Be layers of 1 µm thickness with 25–30 at% D and 3 × 1022 D/m2 comparable to JET-ILW areal concentrations [1] have been produced by High Power Impulse Magnetron Sputtering (HiPIMS) on ITER grade W. Laser pulses of 1, 5 and 10 ms duration heat the layer in vacuum in the Fuel REtention DIagnostic Setup (FREDIS) and release the retained D thermally. By mass spectrometry in FREDIS and subsequent Nuclear Reaction Analysis (NRA) inside the laser spot the desorbed and remaining D is quantified. While a pulse duration of 1 ms cannot fully desorb the deuterium, it is found that a single 5 or 10 ms laser pulse with an absorbed energy density of ca. 1.5 MJ/m2 corresponding to a heat flux factor around 20 MW√s/m2 leads to nearly complete desorption of the retained D. This encourages the development of a useful tritium monitoring system, although the present layers produce some dust due to local delamination of the layer on at least 11% of the heated surface (at 1.4 MJ/m2 absorbed energy within 5 ms) and lead to unavoidable crack formation.

Discrimination of leukemic Jurkat cells from normal lymphocytes via novo label-free cytometry based on fluctuation of image gray values.

We introduce a simple, label-free cytometry technique, based on the spatio-temporal fluctuation analysis of pixel gray levels of a cell image utilizing the Gray Level Information Entropy (GLIE) function. In this study, the difference in GLIE random fluctuations and its biophysical etiology in a comparison cell model of leukemic Jurkat cells and human healthy donor lymphocytes was explored. A combination of common bright field microscopy and a unique imaging dish wherein cells are individually held untethered in a picoliter volume matrix of optical chambers was used. Random GLIE fluctuations were found to be greater in malignant Jurkat cells than in benign lymphocytes, while these fluctuations correlate with intracellular vesicle Mean Square Displacement (MSD) values and are inhibited by myosin-2 and adenosine triphosphate (ATP) inhibitors. These results suggest that the incoherent active forces acting on the cytoskeleton which cause mechanical dissipative fluctuation of the cytoskeletal and related intracellular content are the biophysical cellular mechanism behind the GLIE random fluctuation results. Analysis of the results in Jurkat cells and normal lymphocytes suggests the possible potential of this simple and automated label-free cytometry to identify malignancy, particularly in a diagnostic setup of multiple cell examination.

On using Rayleigh scattering for in situ spectral calibration of Thomson scattering diagnostics.

A new method for in situ spectral calibration of Thomson scattering diagnostics is proposed. The idea of the method is to apply a wavelength tunable optical parametric oscillator for measurements of Rayleigh scattering at different wavelengths, from which relative sensitivities can be calculated. This extends the usual approach where Rayleigh scattering is used only at a single wavelength for the absolute calibration and spectral sensitivities are obtained separately. With the new approach, the full diagnostic setup is spectrally calibrated at once. Such a calibration can be repeated at regular intervals during an experimental campaign since it does not require a break of the vacuum. In this paper, the Rayleigh scattering calibration is tested in a laboratory setup with a sample Wendelstein 7-X (W7-X) polychromator. It is shown that relative sensitivities of spectral channels can be recovered with a sufficient resolution even under conditions of significant stray light. The stray light is overcome by measuring the linear dependence of the scattered signal on the gas pressure. Good results of laboratory tests motivate the installation of the new calibration system for the Thomson scattering diagnostic at W7-X.

Fuel Retention Diagnostic Setup (FREDIS) for desorption of gases from beryllium and tritium containing samples

In fusion devices, the retention of the fusion fuel deuterium (D) and tritium (T) in plasma-facing components (PFCs) is a major concern. Measurement of their hydrogen isotope content gives insight into the retention physics.In FREDIS, two methods of thermal desorption are used for retention measurements: In Thermal Desorption Spectrometry (TDS) the samples are heated by 6 infrared lamps up to 1433 K with linear temperature ramps of up to 1.67 K/s. The desorbed gases are detected up to 100 amu/e with a double-QMS (Quadrupole Mass Spectrometer) that can distinguish between helium and D2 and uses an innovative differential pumping system.In a connected vacuum chamber, a ∅3 mm spot can be heated on the sample surface by a high energy Nd:YAG laser pulse (E0 < 100 J) within milliseconds (0.1–20 ms) to several thousand degrees. This method of Laser-Induced Desorption (LID) can also be applied inside the fusion chamber and is planned as in situ retention diagnostic for ITER. In FREDIS, LID is thus tested and used as ex situ analysis method utilising the same double-QMS for absolute quantification. FREDIS is capable of handling beryllium (Be) by means of glove boxes and in the future also tritium using a tritium trap to analyse also samples from JET and ITER. In this contribution we present the specifications of FREDIS and compare TDS and LID.

Application of Self-Organizing Neural Networks to Electrical Fault Classification in Induction Motors

Electrical winding faults, namely stator short-circuits and rotor bar damage, in total constitute around 50% of all faults of induction motors (IMs) applied in variable speed drives (VSD). In particular, the short circuits of stator windings are recognized as one of the most difficult failures to detect because their detection makes sense only at the initial stage of the damage. Well-known symptoms of stator and rotor winding failures can be visible in the stator current spectra; however, the detection and classification of motor windings faults usually require the knowledge of human experts. Nowadays, artificial intelligence methods are also used in fault recognition. This paper presents the results of experimental research on the application of the stator current symptoms of the converter-fed induction motor drive to electrical fault detection and classification using Kohonen neural networks. The experimental tests of a diagnostic setup based on a virtual measurement and data pre-processing system, designed in LabView, are described. It has been shown that the developed neural detectors and classifiers based on self-organizing Kohonen maps, trained with the instantaneous symmetrical components of the stator current spectra (ISCA), enable automatic distinguishing between the stator and rotor winding faults for supplying various voltage frequencies and load torque values.

A pan-genotypic Hepatitis C Virus NS5A amplification method for reliable genotyping and resistance testing

BackgroundChronic infection with the Hepatitis C Virus (HCV) is associated with the risk of progressive liver disease. Although, HCV treatment options and viral cure rates have tremendously increased over the last decade, all currently licensed combination therapies contain inhibitors of the replication complex NS5A. Resistance-associated substitutions (RAS) in NS5A can limit the efficacy of therapy; however, resistance testing is routinely not recommended for all patients. Notably, pan-genotypic combinations have been approved, however the correct identification of the HCV genotype is still required for treatment decisions and is a good predictor for treatment success. ObjectiveThe aim of this study was the establishment of a pan-genotypic NS5A amplification method for reliable genotyping and simultaneous resistance testing in a fast and cheap routine diagnostic setup. Study designPan-genotypic degenerated nested PCR primer were designed and tested in 262 HCV-patients. The collection included samples from genotypes 1–7 and the median viral load was 1.07 × 106 IU/ml (range 248-21 × 106 IU/ml). ResultsAmplification of the expected 747bp fragment was successful in 257 of 262 (98.1%) samples including samples <1000 IU/ml. The direct comparison of the genotype information obtained with core sequencing to those obtained by NS5A prediction showed high concordance (97.3%) and discrepancies occurred only for relatively rare subtypes. Resistance analysis using Geno2Pheno[HCV] showed NS5A-RAS in 23 of 257 (8.9%) of samples. ConclusionsWe successfully developed a routine diagnostic method for pan-genotypic amplification of NS5A. This amplicon can be used for simultaneous genotyping and resistance testing for enhancing and improving routine HCV diagnostic.

Metabolic response to maxillofacial trauma revisited: A retrospective study.

Purpose:Management of a trauma patient aims at stabilization or resuscitation and revival from critical condition resulting from various sequences of systemic pathophysiological responses in the body. Hematological changes are the first signs reflecting the homeostasis mechanisms starting in the body after injury. The aim of the current study is to evaluate the physiological changes following maxillofacial trauma and extrapolate the findings to understand the posttrauma responses.Patients and Method:This is a retrospective study involving 192 subjects divided into two groups, trauma group and control group. In both the groups, baseline vitals and complete blood picture were recorded for comparison. In trauma group, the recordings were made within 24 h after maxillofacial injury.Results:All the parameters were analyzed using SPSS version 18. Independent sample t-test was used to assess the nature of data distribution and statistical significance was considered only at P value < 0.05. On comparison of complete blood picture mean values of hemoglobin (13.63 vs 12.18), RBC count (4.51 vs 4.10), WBC count (8835.48 vs 8336.56) were seen to be higher in trauma patients compared to control subjects. The mean bleeding times are almost equal (2.35 vs 2.47) but the clotting times (5.42 vs 5.26), random blood glucose (94.78 vs 90.13), and blood urea (27.14 vs 26.30) were marginally higher in trauma group but were statistically insignificant. The mean value of serum creatinine (0.84 vs 0.80) was comparatively higher in trauma patients and was statistically significant. Study of vitals revealed that mean systolic blood pressures were almost equal (120.65 vs 121.08) in both the groups. The mean diastolic blood pressures (79.46 vs 88.49) and oxygen saturation (93.73 vs 98.86) in trauma patients are comparatively reduced. The mean values of temperature (99.30 vs 98.50) and pulse rate (102.38 vs 97.14) were on relatively higher side in trauma group compared with control group.Summary and Conclusion:Using basic blood parameters and vitals in the present study, the compensatory mechanisms happening in the body after maxillofacial trauma can be seen. These changes although significant on side by side comparison can still fall within the normal physiological range provided by various diagnostic setups. Hence, the need for maxillofacial surgeon to be sensitive to minor variations in these aspects to ensure safety of the patient cannot be overemphasized.

Diagnostic setup for the divertor manipulator at wendelstein 7-X

The investigation of plasma wall interactions in terms of erosion processes, fuel retention and new plasma facing components exhibits a scientific gap as discharges in tokamaks and stellarators last only seconds up to a minute. Currently, linear plasma machines are bridging this gap, while Wendelstein 7-X (W7-X) will provide steady-state discharges of up to 30 min in its second operation phase (OP2), in which a divertor manipulator is envisaged to expose samples to reactor-relevant plasma fluxes and fluences. With a design following the limiter lock system at TEXTOR and the DIM-II at ASDEX Upgrade (AUG), the divertor manipulator at W7-X aims to study plasma surface interactions ex-situ by daily/weekly probe exchange and in-situ by embedded diagnostics and an observation system.The design, layout and capabilities of the embedded and observing diagnostics determine the accessible parameters for the in-situ investigation of the exposed probe materials, ranging from plasma edge measurements in the manipulator shaft to intersecting the magnetic island structure on the manipulator head. A versatile laser and observation system adds active surface analysis techniques. To prevent local overheating and excess thermal stress, essential diagnostics for temperature control are identified and combined with first considerations of the manipulator head shaping, based on the field line tracing tool of the W7-X web-service.

Reverse Engineering in Orthodontics.

Three-dimensional (3D) imaging has advanced greatly and is used extensively in orthodontics. It is worth outlining and reviewing the developments of reverse engineering (RE) as its applications are growing more widespread and diverse. Data from an existing object are used to create a digital model. A traditional RE process is usually performed in these stages: (1) obtaining data, (2) restructuring the surfaces, and (3) creating a useful model. They are classified as (1) laser projection based and (2) fringe projection based. This digital technology has been used in creating 3D model scanning, 3D digital model superimposition, diagnostic setup, volumetric assessment of tooth wear, soft tissue facial analysis, incorporation of digital model to 3D facial image, lip position and smile reproducibility, analysis of tooth position after orthodontic treatment, and anthropometric measurements. This system has proven itself to have a varied probability of applications and researches in the field of orthodontics. Similar to every single system, even RE has its own benefits and shortcomings. The complexity of the process and high cost are the major disadvantages reported so far. Rapid advancement of this technology possibly will rapidly inverse the negative results that emerged previously. As a future work, innovative use of RE technology is necessary to make this system triumph in the field of orthodontics.

ICGEB Workshop on Next Generation Diagnostics, 22/03/2018-24/03/2018, Macedonian Academy of Sciences and Arts, Skopje, Republic of Macedonia.

More than 200 participants from Europe, Asia, Africa and South America attended the two days ICGEB Workshop on Next Generation Diagnostics, 22/03/2018-24/03/2018, at the Macedonian Academy of Sciences and Arts (MASA) in Skopje, Republic of Macedonia. The meeting provided an overview of the current and future use of next generation sequencing (NGS), proteomics and other high-throughput technologies in the diagnostic setup of malignant, inherited and communicable diseases. In addition, considerable emphasis was placed on the potential use of these techniques for disease prognostication, patient stratification and monitoring responses to therapy. Specific topics included NGS-based diagnostics of solid tumors, hematological malignancies, inherited and infectious diseases, proteomic-based approaches for biomarker discovery, predictive biomarkers for personalized treatment strategies, and bioinformatic analysis of NGS data. The meeting also provided a unique platform for fruitful discussions between internationally recognized experts and young researchers from developing countries, providing new perspectives and ideas on broader implementation of these techniques for personalized management and care.

An integrated diagnostic setup for the morphological and molecular identification of the Ceratitis FAR complex (C. anonae, C. fasciventris, C. rosa, C. quilicii, Diptera, Tephritidae).

The Ceratitis FAR complex (Diptera, Tephritidae) includes four economically important frugivorous flies (Ceratitis anonae, Ceratitis fasciventris, Ceratitis quilicii, Ceratitis rosa) whose immature stages and adult females cannot be properly resolved through morphological identification. In order to develop a simplified molecular tool for the identification of two of these species (C. rosa, C. quilicii), we selected a subset of six microsatellite markers out of a panel of 16 loci that were previously developed for the molecular differentiation of the taxa within the complex. These six markers were first tested in silico and then used for the actual genotyping of C. quilicii and C. rosa, resulting in the correct identification of all male reference specimens. Here, we propose an integrated morphological and molecular setup for the identification of the four species of the FAR complex. The decision map relies on preliminary DNA barcoding or morphological identification (when possible) to exclude species not belonging to the complex followed by (a) morphological identification of all adult male specimens and female C. anonae, (b) molecular identification via a panel of 16 microsatellite markers for immature stages, damaged vouchers and samples potentially including adult female C. fasciventris/C. quilicii/C. rosa and (c) molecular identification via a reduced panel of six microsatellite markers for samples including only C. quilicii and C. rosa. This simplified diagnostic setup was profitably implemented in the framework of the ERAfrica fruit fly project and will help correctly identify species within the FAR complex for their early detection and monitoring.

Dual-pass upgrade to the Thomson scattering diagnostic on the Prototype-Material Plasma Exposure eXperiment (Proto-MPEX).

The Thomson scattering (TS) diagnostic on the Prototype-Material Plasma Exposure eXperiment has been upgraded to measure electron temperature (T e ) and density (n e ) simultaneously at two axial locations. After the first pass through the vacuum vessel, the exiting laser beamline is re-collimated in the atmosphere and rerouted into the vacuum vessel for the second pass. The upgrade will help diagnose axial T e and n e gradients between the "central chamber" and the target region which are located 1 m and 2.5 m, respectively, downstream from the Helicon radio-frequency source. The TS measurements have given T e ≈ 4-15 eV and n e ≈ 2-4 × 1019 m-3 at the central chamber and T e ≈ 1-2 eV and n e ≈ 1-2 × 1019 m-3 at the target region. The upgrade also increases the number of sampling points at the target region from 3 fibers to 5 fibers, measuring 3 cm radially across the plasma column, and 25 fibers in the central chamber, radially spanning 8 cm. The intensified CCD camera is double triggered for each laser pulse in order to measure (1) the TS and laser stray light and (2) the plasma background light that contains nuisance emission lines and bremsstrahlung. Subtracting the background light from the TS photons improves the temperature and density measurements. Details of the diagnostic setup, axial and radial measurements, and areas for further optimization are discussed.

Time resolved detection of two-plasmon decay using three-halves harmonic emission on the National Ignition Facility.

Supra-thermal (>100 keV) electrons generated by laser plasma interactions can be detrimental to the performance of ignition experiments conducted on the National Ignition Facility (NIF). On a NIF shot, the amount of electrons is estimated by measuring the hard X-rays passing through the hohlraum wall. The primary sources of hot electrons in a hohlraum are Stimulated Raman Scattering (SRS) and two plasmon decay (TPD). While SRS is well diagnosed on the NIF, there has been no diagnosis of TPD. We have designed and implemented a new diagnostic to characterize the time history of TPD on the NIF. The instrument provides a time resolved measurement of the 3/2 ω harmonic emission which is indicative of the presence of TPD. We describe the diagnostic setup, calibration, and the preliminary results obtained on NIF hohlraum experiments. We find evidence of a correlation between measured hard X-rays generated from the hot electron bremsstrahlung and the TPD emission.

Generation of keV hot near-solid density plasma states at high contrast laser-matter interaction

We present experimental evidence of ultra-high energy density plasma states with the keV bulk electron temperatures and near-solid electron densities generated during the interaction of high contrast, relativistically intense laser pulses with planar metallic foils. Experiments were carried out with the Ti:Sapphire laser system where a picosecond pre-pulse was strongly reduced by the conversion of the fundamental laser frequency into 2ω. A complex diagnostics setup was used for evaluation of the electron energy distribution in a wide energy range. The bulk electron temperature and density have been measured using x-ray spectroscopy tools; the temperature of supra-thermal electrons traversing the target was determined from measured bremsstrahlung spectra; run-away electrons were detected using magnet spectrometers. Analysis of the bremsstrahlung spectra and results on measurements of the run-away electrons showed a suppression of the hot electron production in the case of the high laser contrast. Characteristic x-ray radiation has been used for evaluation of the bulk electron temperature and density. The measured Ti line radiation was simulated both in steady-state and transient approaches using the code FLYCHK that accounts for the atomic multi-level population kinetics. The best agreement between the measured and the synthetic spectrum of Ti was achieved at 1.8 keV electron temperature and 2 × 1023 cm−3 electron density. By application of Ti-foils covered with nm-thin Fe-layers, we have demonstrated that the thickness of the created keV hot dense plasma does not exceed 150 nm. Results of the pilot hydro-dynamic simulations that are based on a wide-range two-temperature Equation of States, wide-range description of all transport and optical properties, ionization, electron, and radiative heating, plasma expansion, and Maxwell equations (with a wide-range permittivity) for description of the laser absorption are in excellent agreement with experimental results. According to these simulations, the generation of keV-hot bulk electrons is caused by the collisional mechanism of the laser pulse absorption in plasmas with a near solid step-like electron density profile. The laser energy, first deposited into the nm-thin skin-layer, is then transported into 150 nm depth by the electron heat conductivity. This scenario is opposite to the volumetric character of the energy deposition produced by supra-thermal electrons.

Visible spectroscopy diagnostics for tungsten source assessment in the WEST tokamak: First measurements.

The present work concerns the measurements obtained with the Tungsten (W) Environment in Steady-state Tokamak (WEST) visible spectroscopy system during the first experimental campaign. This system has been developed in the framework of the WEST project that equipped the existing Tore Supra device with a tungsten divertor in order to test actively cooled tungsten Plasma Facing Components (PFC) in view of preparing for ITER operation. The goal of this diagnostic is to measure the PFC sources and the deuterium recycling with spectral, spatial, and temporal resolution adapted to the predicted power deposition profiles on the objects observed. Three kinds of PFCs are monitored: the Ion Cyclotron Resonance Heating (ICRH) antenna and Low Hybrid Current Drive (LHCD) launcher W limiters; one of the 6 W inner bumpers; and the upper and lower W divertors. Large-aperture in-vessel actively cooled optical systems (f-number ∼ 3) were installed for each view and connected to optical fibres. A total of 240 optical fibers can be distributed on various detection systems including a fast response-time, multi-channel, filtered photodetector-based "Filterscope" system, developed by Oak Ridge National Laboratory (USA) as well as grating spectrometers optimized for multi-sightline analysis. The first WEST experimental campaign conducted in 2017 has been dedicated to plasma start-up development during which the visible spectroscopy system has provided crucial information related to the impurity content first and then impurity sources. The diagnostic setup for that first experimental campaign was limited to the inner bumper and outer limiters but was sufficient to demonstrate that the optical setup was in accordance with the specifications. The radiance calibration procedure allowed us to estimate fluxes from the main limiter of about 8 × 1018 atoms/(s m2) and to show a first W source radial profile along the outboard limiter.

Assessment of image quality of a radiotherapy-specific hardware solution for PET/MRI in head and neck cancer patients

Background and purposeFunctional PET/MRI has great potential to improve radiotherapy planning (RTP). However, data integration requires imaging with radiotherapy-specific patient positioning. Here, we investigated the feasibility and image quality of radiotherapy-customized PET/MRI in head-and-neck cancer (HNC) patients using a dedicated hardware setup. Material and methodsTen HNC patients were examined with simultaneous PET/MRI before treatment, with radiotherapy and diagnostic scan setup, respectively. We tested feasibility of radiotherapy-specific patient positioning and compared the image quality between both setups by pairwise image analysis of 18F-FDG-PET, T1/T2-weighted and diffusion-weighted MRI. For image quality assessment, similarity measures including average symmetric surface distance (ASSD) of PET and MR-based tumor contours, MR signal-to-noise ratio (SNR) and mean apparent diffusion coefficient (ADC) value were used. ResultsPET/MRI in radiotherapy position was feasible – all patients were successfully examined. ASSD (median/range) of PET and MR contours was 0.6 (0.4–1.2) and 0.9 (0.5–1.3) mm, respectively. For T2-weighted MRI, a reduced SNR of −26.2% (−39.0–−11.7) was observed with radiotherapy setup. No significant difference in mean ADC was found. ConclusionsSimultaneous PET/MRI in HNC patients using radiotherapy positioning aids is clinically feasible. Though SNR was reduced, the image quality obtained with a radiotherapy setup meets RTP requirements and the data can thus be used for personalized RTP.

MODERN APPROACHES TO THE DETERMINATION OF THE ANGLE OF TEETH INCLINATION IN THE DIAGNOSIS AND PLANNING OF ORTHODONTIC TREATMENT

Aim. To conduct a comparative analysis of existing methods for measuring the angles of inclination of tooth and determining the torque of teeth with orthognathic occlusion. Materials and methods. Inclination angles were measured in 137 patients with physiological occlusion and the standard values of the torques of permanent teeth. Four methods of investigation were used to measure tooth torques. In the first method, the angle of the inclination formed by the occlusal plane and the conditional middle vertical of the tooth was measured by the protractor on the incisions of the plaster models of the dentition rows. The second method, which allows evaluating torques and teeth angulation at the same time, was carried out with the aid of the «Arco-zet» apparatus of «Scheu Dental GmbH». As the third method of research, the technique of analyzing images of cone-beam computed tomography was used, on which linear and angular reference points were applied. The fourth method of investigation was based on the results of scanning gypsum models with a laser scanner with the subsequent creation of a digital three-dimensional image and the formation of a virtual Set-Up model in the file 3Txer 2.5.0. Results. All methods of measuring the angles of teeth in the vestibular-lingual direction can be applied both in the applied and in the clinical aspect. Determining the torques of permanent teeth using the morphometry of gypsum models of dentition and instrumentation method is characterized by laboriousness, length of studies, and also the presence of errors in measurements. Methods for analyzing images of cone-beam computed tomography and using the virtual diagnostic SetUp model in the ORAPIX file 3Txer 2.5.0 are high-tech, precise, and reproducibility and interpretation of the results allows using the available angular and linear parameters for assessing the effectiveness of conducted orthodontic activities at all stages of treatment. Conclusion. The introduction into clinical orthodontics derived from research boundaries reference values and confidence intervals inclination angles of the upper teeth, the lower jaw, as well as tilt incline of teeth of antagonists will reduce the time required for the early stage diagnosis and increase the effectiveness of the test results of orthodontic treatment. Improvement of existing methods of diagnosis of dentoalveolar anomalies has led to the creation of high-tech, precision, computerized measurement methods, the introduction of which will allow not only minimizing errors associated with instrumental measurement techniques in the structures of the maxillofacial region, but, due to the predictability of orthodontic treatment, achieving optimal functional – aesthetic results.

Novel diagnostic for precise measurement of the modulation frequency of Seeded Self-Modulation via Coherent Transition Radiation in AWAKE

We present the set-up and test-measurements of a waveguide-integrated heterodyne diagnostic for coherent transition radiation (CTR) in the AWAKE experiment. The goal of the proof-of-principle experiment AWAKE is to accelerate a witness electron bunch in the plasma wakefield of a long proton bunch that is transformed by Seeded Self-Modulation (SSM) into a train of proton micro-bunches. The CTR pulse of the self-modulated proton bunch is expected to have a frequency in the range of 90–300 GHz and a duration of 300–700 ps. The diagnostic set-up, which is designed to precisely measure the frequency and shape of this CTR-pulse, consists of two waveguide-integrated receivers that are able to measure simultaneously. They cover a significant fraction of the available plasma frequencies: the bandwidth 90–140 GHz as well as the bandwidth 255–270 GHz or 170–260 GHz in an earlier or a latter version of the set-up, respectively. The two mixers convert the CTR into a signal in the range of 5–20 GHz that is measured on a fast oscilloscope, with a high spectral resolution of 1–3 GHz dominated by the pulse length. In this contribution, we describe the measurement principle, the experimental set-up and a benchmarking of the diagnostic in AWAKE.