Impacts of Phantom Off-Center Positioning on CT Numbers and Dose Index CTDIv: An Evaluation of Two CT Scanners from GE

The purpose of this work is to evaluate the impacts of body off-center positioning on CT numbers and dose index CTDIv of two scanners from GE. HD750 and APEX scanners were used to acquire a PBU60 phantom of Kagaku and a 062M phantom of CIRS respectively. CT images were acquired at various off-center positions under automatic tube current modulation using various peak voltages. CTDIv were recorded for each of the acquisitions. An abdomen section of the PBU60 phantom was used for CT number analysis and tissue inserts of the 062M phantom were filled with water balloons to mimic the human abdomen. CT numbers of central regions of interests were averaged using the Fiji software. As phantoms were lifted above the iso-center, both CTDIv and CT numbers were increased for the HD750 scanner whilst they were approximately constant for the APEX scanner. The measured sizes of anterior-posterior projection images were also increased for both scanners whilst the sizes of lateral projection images were increased for the HD750 scanner but decreased for the APEX scanner. Off-center correction algorithms were implemented in the APEX scanner. Matching the X-ray projection center with the system’s iso-center could improve the accuracy of CT imaging.

Constitutional Features of the Maxillofacial Area of Omsk Young Men

The aim was to determine the morphometric parameters of the maxillofacial area of Omsk young men of 18-20 years of age according to the teleroentgenography of the head (in a lateral projection), taking into account the indicators of cephalometry and anthropometry, to identify regional constitutional features of quantitative values.Material and methods. A cephalometric and somatometric examination of 26 Omsk Slavic young men of 18-20 years of age without concomitant pathology was performed, supplemented by an X-ray examination of the head (to obtain teleroentgenograms in a lateral projection). The analysis of teleroentgenograms was carried out in the online service Mave Cloud.Results. According to the results of anthropometry, the longitudinal and transverse dimensions of the young men's heads, the zygomatic diameter and the full height of the face were assessed; the indicators of body growth, body weight, chest circumference and transverse chest diameter were determined. These indicators were used to calculate the indices. The value of the facial index was 81.86 (79.31; 88.88), the value of the head index was 76.65 (74.27; 79.47), the Rees-Eisenck index corresponded to 97.58 (94.62; 107.48), the Rohrer index was 13.34 (12.07; 15.48), the Pinier index was 11.1 (-10; 22), the Quetelet II index was 23.33 (22.03; 27.71). When analyzing teleroentgenograms, it was revealed that the values of some parameters in Omsk young men of 18-20 years of age differ from the values of the «norm». Thus, the indicators of the lower jaw length (Go-Gn), the ratio of the body of the lower jaw length to the length of the anterior base of the skull (Go-Me/S-N), the length of the posterior base of the skull (S-Ar), the height of the branch of the lower jaw (Ar-Go), the ratio of the heights of the face (S-Go/N-Me), the angle between the axis of the lower incisor and the plane of the lower jaw (IM IMPA) have greater values than the «norm»; and the figures of the angles sum according to Bjork (∠SUM Bjork), mandibular angle (∠Ar-Go-Me), maxillary angle (∠N-Go-Ar), upper jaw inclination angle (∠NSL-NL), lower jaw inclination angle (∠NSL-ML), intermaxillary angle (∠NL-ML), the angle between the lower jaw plane and the Frankfurt horizontal (∠FMA), have values less than the «norm». The values of the saddle angle (∠N-S-Ar) differed in young men with euryprosopic and leptoprosopic facial forms. The quantitative values of the lower jaw angle (ArGo-Me) and the upper jaw angle (N-Go-Ar) differed only in the representatives of the dolichocephalic and mesocephalic forms of the head.Conclusion. Quantitative values of cephalometric and somatometric parameters in Omsk young men of 18-20 years of age have distinctive features. Individual parameters of the maxillofacial area (according to teleroentgenograms) differ in persons with dolichocephalic and mesocephalic forms of the head and in the representatives of euryprosopic and leptoprosopic forms of the face.

The influence of carbon component structure of graphene containing shungite on its electrical conductivity.

The investigation of the influence of carbon component structure of graphene containing shungite on its electrical conductivity is carried out. Five shungite samples from three different deposits with the same carbon content equal to 97% were selected as the object of research. It is established that the integral conductivity of specimens which is measured by four-contact method is changed in frames from 600 Sm/m to 2500 Sm/m. For the interpretation of so large scattering of data by equal concentration it was undertaken the investigation of carbon component structure on nano-level which was made by method of high-distinguish raster electron microscopy. By this method on the microscopic section of these specimens was obtained the cards of surface distribution of graphene slides and graphene packets. For the analysis of conductivity of specimens on the basis of these cards it was employed the method of independent channels. This method employs the presentation of specimen as a combination from parallel current-leading channels with following distribution of channel to cubic space blocks. The successive connection of blocks with accounting of slides orientation determines the total resistance of each channel and the parallel connections of all channels determines the specific conductivity of specimen as a whole. For the obtaining the quantity characteristics the whole card was distributed to some more small regions – fields. In this case the obtained results are averaged by the whole square of card. For the analysis of the field the method of square discretization was used. By this method the whole field id distributed to individual squares which dimension is near to the dimension of graphene packet. It was established that the character of structure in each square has two variants: first when the slides of graphene has clear determined spatial orientation ant the second when special orientation is absent and by orientation the squares are neutral. It is made the quantity analysis of neutral squares along the all specimens. It is shown that the normalized quantity of neutral squares is straight proportional to specific conductivity of specimen. The analysis of slides graphene orientation in squares with clear determined spatial orientation is carried out. For investigation of space structure of channel, the square was identified with lateral projection of block along two coordinates. The dependence of block resistance from the slide orientation is found. It is shown that the block resistance by the flowing of current across the graphene slides is more than order exceeds the resistance by the flowing of current along the slides of graphene. It is shown that the most role in formation of channel resistance play the blocks which graphene slides are oriented across the current flowing. By the adding of channels along the structure of volume unit it was founded the specific conductivity of specimen as a whole. It is established that the obtained meanings of conductivity for all specimens exceed the obtained by contact method on several times. As a reason of this exceeding it is established the absence of accounting the influence of enough small conductivity of intervals between slides and packets and also the absence of accounting of incomplete filling of squares by periodic structures. It is shown that the optimal in plane of correspondence to experiment is the introduce the normalization coefficient of conductivity of intervals which is equal to 0,2222. For the accounting of incomplete filling of squares by periodic structures it was carried out the binary discretization of most typical blocks with the resolution near 0,2 nm which is near the thickness of graphene slide. Along the obtained selection there was the averaged coefficients of filling of carbon which are equal from 0,10 to 0,15 parts for the whole volume of blocks. With the normalized conductivity of intervals and coefficients of filling of blocks it was found the integral conductivity for all specimens. It is shown that the obtained values are near the measured by contact method in the precision not more than 37%. In brief it is discussed the quality reason of apparent paradoxical increasing of integral conductivity by decreasing on structural character of carbon. It is established that the main reason of this increasing is the decreasing of contribution of graphene slides having large resistance which are oriented across the flowing of current.

The Angle of the Microguidwire on the Lateral Projection: a Prediction of Cannulation of the Occluded Inferior Petrosal Sinuses for the Transvenous Embolization of Cavernous Sinus Dural Arteriovenous Fistulas

OBJECTIVE: To describe that the angle of the guidwire on lateral projection under fluoroscopic image is a prediction of cannulation of the occluded inferior petrosal sinus in the transvenous embolization of cavernous sinus dural fistulas.METHODS: From January 2018 through January 2021, 12 consecutive cavernous sinus dural fistulas with ipsilateral inferior petrosal sinus occlusion identified in 12 patients were cured by cannulation of the occluded ipsilateral inferior petrosal sinus. Clinical, radiologic and procedure data of the 12 patients were retrospectively reviewed. The angle of microguidewire between on lateral projection under fluoroscopic image between the inferior petrosal sinus and the internal jugular vein was measured by 180°Protractor(Deli Group Co., LTD, Zhejiang, China). RESULTS: In the 12 patients, access via the occluded ipsilateral inferior petrosal sinus was primarily attempted as the transvenous approach. During the procedure, the angle of microguidwire on lateral projection under fluoroscopic image between the inferior petrosal sinus and the internal jugular vein was 117°±7°, which is very useful to confirm the cannulation of the occluded inferior petrosal sinus. Complete occlusion was achieved in all fistulas, with no procedure-related morbidity or mortality. Postprocedural symptom was improved in all patients. CONCLUSION: Cannulation of an occluded inferior petrosal sinus is possible and reasonable as an initial access attempt for cavernous sinus dural fistulas. The angle of microguidwire on the lateral projection under fluoroscopic image can help to confirm the orifice of the occluded inferior petrosal sinus.

Proper Management of the Clinical Exposure Index Based on Body Thickness Using Dose Optimization Tools in Digital Chest Radiography: A Phantom Study

In radiography, the exposure index (EI), as per the International Electrotechnical Commission standard, depends on the incident beam quality and exposure dose to the digital radiography system. Today automatic exposure control (AEC) systems are commonly employed to obtain the optimal image quality. An AEC system can maintain a constant incident exposure dose on the image receptor regardless of the patient thickness. In this study, we investigated the relationship between body thickness, entrance surface dose (ESD), EI, and the exposure indicator (S value) with the aim of using EI as the dose optimization tool in digital chest radiography (posterior–anterior and lateral projection). The exposure condition from the Korean national survey for determining diagnostic reference levels and two digital radiography systems (photostimulable phosphor plate and indirect flat panel detector) were used. As a result, ESD increased as the phantom became thicker with constant exposure indicator, which indicates similar settings to an AEC system, but the EI indicated comparatively constant values without following the tendency of ESD. Therefore, body thickness should be considered under the AEC system for introducing EI as the dose optimization tool in digital chest radiography.

Ultrasound examination of swallowing disorder characteristics in patients with oncopathology of the oral cavity

The aim of the study was to compare the dynamics of oral and oropharyngeal muscles contraction during swallowing in normal individuals and in patients with malignant tumors depending on the clinical disease using ultrasound. Materials and methods. The study included 29 patients aged 38–55 years (men), normtrophic, who were treated in the Department of Head and Neck Tumors of Podolsk Regional Oncology Center for malignant tumors of the tongue, floor of the mouth and oropharynx. Among them, there were 12 patients with cancer of the lateral tongue surface, 9 - with oral mucosa cancer and 8 – with tongue base cancer. Scanning was performed in the sagittal and frontal planes with a 7.5 MHz sensor in two modes (B and M) at rest and during swallowing in several stages on the TOSHIBA device (Model USDI-A500A/EL; Serial No. ELA14Z2082). B-mode was the main one in all the studied areas where one image frame was vertically lined up. The swallowing act was assessed in M-mode (a length of the axial movement). The obtained indicators were compared with the normal ones. Results. The work was carried out to verify the musculoskeletal complex involved in the act of swallowing. Measurements of several indicators were performed revealing a violation of the swallowing act, namely a decrease in indicators in the longitudinal and lateral examination of the sublingual muscle group in B-mode and M-mode in patients diagnosed with cancer of the tongue base and mucosa of the mouth floor. In addition, a deviation and displacement of the musculoskeletal complex to the healthy contralateral side with preserved muscle function in patients diagnosed with the lateral tongue surface cancer was revealed by M-mode ultrasound of the swallowing act. Conclusions. In patients with malignant tumors of the lateral tongue surface, the longitudinal examination of the sublingual muscle group in B-mode ultrasound showed decreased indicators by 7 % and in the lateral projection of the anterior belly of the digastric muscle in M-mode – by 3.5 times. In tongue base cancer, the mentohyoid distance was merely 4 mm reduced during the act of swallowing, and in the longitudinal projection of the sublingual muscle group - by only 5 %. In oral mucosa cancer, there was the lowest reduction in the mentohyoid distance, about 4 mm when swallowing, (in healthy people 8–12 mm) and decreased indicators in longitudinal examination of the sublingual muscle group by 8 % in B-mode, in lateral M-mode ultrasound – by 2 mm.

OCCLUSAL PLANE ORIENTATION IN PATIENTS WITH DENTOFACIAL ANOMALIES BASED ON MORPHOMETRIC CRANIO-FACIAL MEASUREMENT

Based on 79 lateral projection head teleroentgenograms obtained from relatively young patients (median age, 37.4±4.3), we have developed a method for the occlusal plane orientation in view of cranio-facial anatomical reference points. As stable anthropometric reference points, we employed the gnathic angle shaped by the spinal and mandibular planes, as well as the interalveolar angle, where the subspinal Downs point and the supramental point were employed as retention elements. When reconstructing the occlusal plane in patients with dentoalveolar anomalies, the construction of the bisector of the interalveolar angle was explained as a key reference point, which allows diagnosing occlusion anomalies in the vertical direction (symmetrical and asymmetric) not only in the lateral, yet also in the frontal segment of the dental arches. The method developed for constructing the occlusal plane does not depend on the position of the incisors and the second permanent molars, which can be used to identify the vertical deformation of the dental arches.