CC BY
4Medvedev D.A. *
Master's Degree student Institute of Physics and Technology Ural Federal University named after the first President of Russia B.N. Yeltsin
Markina Sofia candidate of engineering sciences, professor Institute of Physics and Technology Ural Federal University named after the first President of Russia B.N. Yeltsin
THE ALGORITHM DESCRIBING POSITION OF THE SPONGY SCREWS ON A WORK PIECE OF THE VERTEBRA IMPLANT
Summary
This article describes the features of the operations for bone tuberculosis. The analysis of the subject area and described the epidemiological situation in the Russian Federation. This article describes modern methods of elimination of the consequences of osteoarticular tuberculosis. Also, held criticism of the considered procedures. An alternative method of conducting transactions using rapid prototyping technologies was offered. For fixation of implants, a mathematical algorithm to describe the position of spongy screws on the workpiece of the implant to the vertebra has been developed. Used balanced histogram thresholding method to segment and subsequent binarization of images of a computer tomograph. Established the coordinates of the entry points and the ends of the channel for the spongy screws. The results of this article mathematically describe the location of the screws. Also the simulation method subsequent fixation of the implant using spongy screws was offered.
Keywords: CT scans, osteoarticular tuberculosis, 3D modeling, spongy screws.
1. Introduction
Under the modern epidemiological situation os-teoarticular tuberculosis takes the fourth place in disease and morbidity distribution of extrapulmonary tuberculosis within the territory of the Russian Federation and makes up 8-12% of the total number of tuberculosis diseases.
Bones and joints tuberculosis is the most common form of surgical tuberculosis. The process can proceed in all bones and all joints but more frequently it occurs in such vertebrae and major joints as: hip joint, knee joint, shoulder joint, elbow joint and the wrist joint.
Nowadays there are a great number of ways to primary stabilize a damaged segment of the vertebral column: transpedicular fixation, front technique, rear technique or its combination. Today, the most appropriate way of surgical intervention concerning the damaged segment of the vertebral column is the combination of rear spondylodesis and front corporodesis using modern metal constructions [1]. It is absolutely clear that having such internal fixation one succeeds in stabilizing that damaged segment of the spine in the best possible way.
Nevertheless, these techniques have an undeniable drawback: in this way only a weight-bearing function is restored while a biomechanical function is irretrievably lost. Another disadvantage consists in the fact that doctors can not understand the exact size of the required implant before surgery. For this very reason the selection of the implant is made exactly during surgery while a patient is under the effects of anesthesia.
On this basis, it was proposed to simulate implants in advance using medical images of a patient that were obtained from a computed tomography scanner and then to use a rapid prototyping technology for their manufacture.
The method of subsequent fixation of a prepared implant is an essential thing. If this fixation is unreliable under the load then implant displacement may occur and it, in its turn, will cause injuries of inner parts of a human body. To prevent such result it is necessary to add channels for the spongy crews to the implant model that are designed for a specific patient with a focus on optimal fixation.
2. The purpose of the study
To develop the algorithm describing position of the spongy screws on a work piece of the vertebra implant, constructed on the basis of computed tomography scanner images for further printing by using a rapid prototyping technology.
3. Material and methods
The study is based on a set of computed tomography scanner images of a patient and on an implant workpiece that was created using AutoCAD software.
The algorithm consists of the following steps:
1. First, it is necessary to separate out a damaged segment of the vertebral column. To perform this task MeVisLab software product was used [2];
2. Then, it is essential to perform image segmentation to make the further analysis simple;
3. After it, one establishes the coordinates of the entry points of screws and spinous processes;
4. Later, the coordinates of the channel ends for the spongy crews are calculated;
5. Finally, a work piece is joined to a plate followed by fixation and channels for the spongy crews are added.
4. Calculation of channels location for the spongy crews
The body of the model consists of three parallel surfaces: cranial, medial and caudal.
The schematic diagram of these 3D surfaces is shown in Figure 1.
Figure 1 - 3D projection of the model diagram
After making a work piece it is necessary to create channels for the subsequent implant fixation with the help of spongy screws. To do this, we need to calculate two coordinates for each screw:
a) the entry point of the screw at the spinous process;
b) the end point of the channel for the screw.
As a first step we perform the calculation of the entry points to the arc root for the spongy screws. To do this, the following anatomical landmarks are used:
a) a transverse process, usually corresponding to the level of the arc root in the lumbar spine;
b) a caudal part of the joint facet lower part;
c) the crest located at the junction of the articular and transverse processes with the arc plate.
To perform the calculation, it is necessary to know the following anatomical parameters: horizontal and vertical diameters of the arc root; a transverse pedicular angle between a line which is parallel to the vertebra middle and an axis line of the arc root; a sagittal pedicular angle between an axis line of the arc root and the upper part of the end plate of the implant body [3]. All these parameters are shown in Figure 2.
a) the screw insertion trajectory in the axial plane;
b) the point projection of the screw introduction in the rear parts of the vertebral column;
c) the screw insertion trajectory in the sagittal plane.
Figure 2 - the main anatomical parameters
In the course of this investigation it has been statistically found out that the screw direction angle in the thoracic spine is 30°.
The horizontal diameter of the arc root is calculated according to CT scans. But first it is necessary to prepare them to automate the process of measurements.
Segmentation is applied for image processing and its analysis, i.e. one can see image separation into the
areas, for which a certain criterion of homogeneity is satisfied, for instance, the selection of the areas of approximately the same intensity in the image. The concept of the image is used to define a connected group of voxels which have a definite common feature (attribute).
One of the main and the easiest ways to make image segmentation is to use a threshold. The threshold is a feature (attribute), which helps to divide a required signal into some classes. The operation involving threshold separation consists in comparison data value intensity of each image voxel with a predetermined value of the threshold [4].
The balanced histogram thresholding method was used to segment images.
The balanced histogram thresholding method is a very simple method used for automatic image thresholding. Like Otsu's method, this is a histogram-based thresholding method. Assuming that the image is divided into two main classes: the background and the foreground, this method tries to find the optimum threshold level that divides the histogram in two classes. This method weighs the histogram, checks which of the two sides is heavier, and removes weight from the heavier side until it becomes the lighter. It repeats the same operation until the edges of the weighing scale meet. This method may have problems when dealing with very noisy images, because the weighing scale may be misplaced. The problem can be minimized by ignoring the extremities of the histogram. [5]
After segmentation we measure the size of the area that has been received and obtain the horizontal diameter of the arc root. By the same procedure we calculate the vertical diameter of the arc root and find out the entry point of spongy screws. We repeat all
steps for the opposite side of the vertebra. As a result, we obtain the coordinates of the point of intersection of two diameters.
As a next step it is necessary to calculate the approximate end point for the spongy screws. For this purpose, in the medial plane we draw an interval, which connects the middle of the arc formed by the vertebral foramen with the middle of the arc in the front part of the implant. Then from its center we lay off two more intervals to the front part of an implant at an angle of 45°.
Having connected the middles of these two intervals with the middle of the arc in the front part of an implant, we will obtain an isosceles triangle ABC.
According to the results of statistical data the level of the screw end is equal to one fifth of the distance between the medial and cranial plane. A created projection of the triangle at this level is shown in Figure 3.The points B and C that we have got will be the end points of the channel for the spongy screws.
Figure 3 - The triangle ABC that we have obtained
5. An example of the subsequent implant fixation
During the research, a method of the subsequent implant fixation has been simulated (Figures 4-5).
Figure 4 - an example of the implant fixation
Figure 5 - an example of the implant fixation
6. Results
Thus, the mathematical algorithm describing position of the spongy screws on the basis of CT scans has been developed.
7. Discussion and conclusion
The analysis concerning the subject field has been carried out and the drawbacks of the modern method of conducting transactions using rear spondy-lodesis and front corporodesis have been mentioned. As a result of this work we have received this subsequent fixation implant model.
References
[1] Combined anterior stabilization of uncomplicated of thoracic and lumbar spine lesions [electronic resource]. - Mode of access: http://cardio-tomsk.ru/attachments/article/266/SMJ-3-1-2010.pdf.
[2] Markina S.E., Pamyatnykh V.Y. About possibilities of computer visualization of the medical data in MeVisLab program, [electronic resource]. - Mode of access: http://www.rae.ru/forum2012/pdf/2888.pdf.
ssüLB Wschodnioeuropejskie Czasopismo Naukowe (East European Scientific Journal) #12, 2016
[3] Mazurenka A.N., Lumbar transpedicular fixation in deformities and degenerative disease [electronic resource]. - Mode of access: http://www.mednovosti.by/journal.aspx?article=5249.
[4] Image segmentation [electronic resource]. - Mode of access: http://habrahabr.ru/post/128768/.
[5] Chaki, N.. Shaikh, S.H., Saeed. K. (eds.): "Exploring Image Binarization Techniques". SCI, vol. 560. Springer, Heidelberg (2014)
УДК 621.311.25
Volodymyr Moroz
Postgraduate Odessa National Polytechnic University. Odessa, Ukraine
Мороз Володимир Анатолшович
AcnipaHm Одеського нащонального полiтехнiчного yuieepcumemy, м. Одеса, Украша
ECOLOGICAL MONITORING OF WATER QUALITY FOR NPP TURNAROUND WATER SUPPLY SYSTEMS ЕКОЛОГ1ЧНИЙ МОН1ТОРИНГ ЯКОСТ1 ВОДИ СИСТЕМ ЗВОРОТНОГО
ВОДОПОСТАЧАННЯ АЕС
Виконано аналiз природоохоронно'1 дiяльностi та оцiнка стану водних o6'eKmie АЕС Украши за ос-новними показниками води. Приведено аналiз стану кнуючого монторингу якостi води системи зворо-тного водопостачання АЕС та практичне значення екологiчного монторингу при вдосконаленш системи з метою регулювання техно-екосистеми водних об'eктiв для забезпечення надiйностi та безпеки основного технологiчного обладнання АЕС. Розроблений комплекс математичних моделей, який дозволяе пiдвищити яюсний рiвень екологiчного монторингу, осюльки тдвищуеться оперативтсть контролю, удосконалюеться яюсть монторингу за рахунок додаткових функцш оцтки та прогнозу при рiзних по-еднаннях внyтрiшнiх та зовнштх чинниюв, врахованих в моделi, дозволяе виконати оцтку гiдрохiмiчно-го стану систем зворотного водопостачання при аваршних ситуа^ях та Их запобiгання, а також виро-бити комплексну оцтку можливих на^дюв при рiзних технологiчних режимах.
Ключовi слова: яюсть води, математична модель, система зворотного водопостачання АЕС, тех-но-екосистема, екологiчний мотторинг
Nature protection activities are analyzed and NPP water objects condition of Ukraine according to main water criteria is evaluated. Current water quality monitoring condition of NPP of turnaround water supply system is analyzed and environmental monitoring practical importance when system improvement for the purpose of the main NPP equipment water objects technical ecosystem adjustment for reliability and safety assurance is shown. Mathematical model complex allowing to enhance the environmental monitoring quality is worked out. The last is enhanced according to optional estimating functions under different combinations of internal and external factors. This complex allows to estimate the turnaround water supply system hydrochemical condition in event of incidence and their prevention and also to evaluate probable consequences under different process conditions.
Keywords: water quality, mathematical model, NPP turnaround water supply system, technical ecosystem, environmental monitoring.
Вступ.
Атомна енергетика е одшею з важливих скла-дових державного енергетичного потенщалу та займае лвдируюче положения в енергетичному забезпеченш кра!ни. На тл прогресуючо! деграда-ци теплових електростанцш, дефщиту оргашчного палива, атомш електростанци демонструють вщ-носно надшну та ефективну роботу.
Безумовно, дш об'ектш ядерно! енергетики на довшлля, як i електростанцш шших тишв, мае ба-гато аспекпв. Один з них пов'язаний з необхвдшс-тю використання велико! шлькосп води для охо-лодження конденсаторiв турбш та допомiжного теплообмшного обладнання АЕС. Тому створю-ються водоймища-охолоджувачi (ВО), будуються градирш, бризкальш басейни.
ВО е не лише техшчним водним об'ектом спещального призначення, але й елементом ланд-
шафтного комплексу того або шшого регюну. Оскшьки ВО знаходяться тд безпосередшм впли-вом АЕС, !х стан пiдлягае не лише контролю, але, в певних межах, й управлшню.
Наявшсть прямих та зворотних зв'язшв мiж водними екосистемами та гвдротехшчними спору-дами АЕС привела до доцшьносп введення понят-тя «техно-екосистема» [1]. Тому, питання про еко-логiчний стан водоймищ, увiмкнених в систему водопостачання АЕС не може вирiшуватися лише в традицшному аспектi «охорони довкшля», а повинен розглядатися в аспекп «регулювання техно-екосистеми на еколопчно безпечному рiвнi».
Постановка мети та задач дослвдження.
Мета дослiдження - удосконалення еколопч-ного монiторингу для можливосп регулювання режимiв експлуатацi! систем зворотного водопостачання АЕС з метою забезпечення якосп води на
