RU2814723C1 - Method of enclosing biomaterial in gelatinous medium for temporary storage and subsequent scanning on computer tomograph - Google Patents

Abstract

FIELD: biotechnology.

SUBSTANCE: invention relates to biotechnology and is a method of enclosing a biomaterial in a gelatinous medium for temporary preservation and subsequent scanning on a computer tomograph, where the biomaterial is washed with 0.9 vol.% sodium chloride solution, then preparing the gelatinous medium, placing the biomaterial on the bottom of the plastic dish and pouring the prepared gelatinous medium, then the gelatine block with the enclosed biomaterial is removed from the plastic dish, while maintaining its integrity, after which the biomaterial is ready for examination on a computer tomograph.

EFFECT: present method is used to create atlases and visual teaching aids containing both anatomical preparations and tomograms and 3D reconstructions, for professional training of radiographers, pathologist and forensic medical experts within the framework of post-mortem radiation diagnostics methods training.

1 cl, 4 dwg

Description

The invention relates to medicine, namely to morphology, normal anatomy, pathological anatomy, radiation studies, museum work, namely museum technology.

Virtopsy is a set of methods for post-mortem examination of the body, combining a classical pathological or forensic autopsy with the preliminary use of the basic methods available in modern radiation diagnostics: computed tomography (CT), magnetic resonance imaging (MRI), radiography, angiography, 3D photogrammetry , magnetic resonance spectrometry.

Among the various imaging modalities used in virtopsy, CT plays a central role in providing detailed information about the internal structures of the body and individual organs. Its advantages include: high accuracy of diagnosis of bone traumatic pathology, including pathology of the facial part of the skull, good visualization of hemorrhages, gunshot and blast wounds, as well as less sensitivity to physicochemical changes occurring in the body after the cessation of vital activity. Other positive aspects of postmortem computed tomography include high scanning speed with the ability to create 3D reconstructions in several planes. According to WHO, the share of autopsies of the dead in the countries of the European Union in 1989 was 23.5%, and in 2020 it is already 11.1%, which is associated with religious and cultural reasons, as well as with trust in the results of intravital diagnostics. The prospects for the development of virtopsy and its further implementation in practice are associated not only with the convenience of the method and the tendency to abandon classical post-mortem research, but also with the multidisciplinary approach that modern medicine requires.

Virtopsy tools allow you to examine both the entire body and its individual parts or organs. In the context of studying certain pathologies, including archival pathological material, it is more convenient to resort to the study of individual parts or organs. To maintain the mechanical, chemical and biological isolation of the sample being studied, it is necessary to create a special isolating medium that has the properties of external inertness and the ability to preserve the biological material enclosed in the medium.

Currently, research is actively being carried out in the field of post-mortem radiation diagnostics, as well as its implementation in practice to assess the causes of death and other pathological conditions within the framework of post-mortem diagnostics, which in turn dictates the need to create comparative visual teaching aids and atlases between the results of autopsy and virtopsy. The study of the structural features and pathologies of individual organs, thus, contributes to the accumulation of an archive of finished anatomical preparations and a database in the form of digital images.

There are a number of known methods for preserving biological material in an isolating environment.

The well-known method of G.V. Shor allows one to preserve biological material in dry form through gelatinization. First, it is fixed, restored to color and transferred to Shor’s preservative liquid, after which it is stored for no more than two weeks. Then it is dried in air in a suspended state, removing excess moisture with absorbent cotton, after which the preparation is covered with a thin layer of hot gelatin in 1-2% carbolic water using a soft brush. The preparation is hung loosely on a thread and left in this form in the air, allowing excess gelatin to drain and waiting for it to harden for 10-15 minutes, after which, to tan the gelatin, the preparation is placed in a 20% formaldehyde solution for 5-15 minutes. A chamber is made from organic or ordinary glass according to the size of the organ, and the edges are carefully covered with Mendeleev putty. To prevent moisture from condensing, place burnt magnesia on cotton wool in the corner of the chamber.

However, this method has a number of disadvantages, such as the duration of the preparatory stage and the high consumption of fixing, restoring and preserving solutions, as well as the inevitable violation of anatomical, topographical and dimensional characteristics during the drying process. Also, the disadvantages of the method include a fairly thin layer of insulating medium.

There is a known method for producing plate-like preparations according to N.K. Lysenkov’s method, based on enclosing cuts and sections of organs in flat vessels or glass frames filled with a solidifying transparent medium. Frozen cuts are washed with water and placed in a 2% formaldehyde solution and kept for at least three weeks. Then the cuts are removed, dried in air and filled with Kaiser's glycerin-gelatin solution and placed between zinc strips with glasses fitted to them or Petri dishes.

The disadvantages of this method are the presence of artifacts created by zinc strips during CT examination, as well as the duration of the preparatory stage and the violation of anatomical, topographical and dimensional characteristics during the drying process.

The method according to V.T. Talalaev is known, which we take as a prototype (Talalaev V.T. Lamellar pathological-anatomical preparations and techniques for their production. Selected works. M., Medgiz, 1953, pp. 193-201). Pathological preparations from organs and tissues are made in the form of plates and enclosed in gelatin or agar-agar: a thin plate of 1-1.5 cm is cut out from a fresh, unfixed organ, which is fixed and processed according to the Keyserling method. After fixation, the plate is wrung out and passed through 96° alcohols and dried in air. Next, it is poured into acetic acid agar and the preparation is placed between two glasses. Immediately place a plate from the organ into melted gelatin or agar-agar and press it tightly against the glass bottom of the box.

The disadvantage of this method is that alcohol significantly dehydrates tissues, thereby distorting their normal sizes and topographic relationships. There are also disadvantages associated with the inability to prepare a full-size anatomical specimen. In addition, due to the too thin section of 1.5 cm, it is not possible to fully scan the specimen using a computed tomograph.

The technical result consists in developing a method for enclosing a biomaterial in a gelatin medium for temporary preservation, followed by CT examination of the anatomical specimen.

The technical result is achieved by washing the biomaterial with 0.9 vol. % sodium chloride solution, then prepare the gelatin medium as follows: place 1 liter of distilled water and 60 g of gelatin in a container, keep the resulting solution for 30 minutes until the gelatin granules swell, then heat in a water bath to 60 ° C, then add to the solution add 5 g of phenol and stir until a homogeneous transparent mass is obtained, after which the biomaterial is placed on the bottom of a plastic dish and filled with the prepared gelatin medium, close the dish with a plastic lid and leave until the gelatin medium has completely hardened for 1 hour, then the gelatin block with the enclosed biomaterial is removed from the plastic dishes, maintaining its integrity, after which the biomaterial is ready for examination in a computed tomograph.

THE INVENTION IS EXPLAINED BY FIGURES (Fig. 1 - 4).

In fig. 1 preparation of a sagittal section of the knee joint, enclosed in an insulating gelatin medium.

In fig. 2 tomogram of the knee joint, enclosed in an insulating gelatin medium.

In fig. 3 preparation of a frontal cut of the distal femur, enclosed in an insulating gelatin medium.

In fig. 4 tomogram of the distal femur, enclosed in an insulating gelatin medium.

Unlike a macroscopic specimen, a CT scan clearly visualizes the exact thickness of the bone wall, as well as the presence of calcifications in the femoral artery .

The method is carried out as follows: the biomaterial is prepared using a band saw to obtain cuts 5 cm thick, then the biomaterial is washed with 0.9 vol. % sodium chloride solution, then prepare the gelatin medium as follows: place 1 liter of distilled water and 60 g of gelatin in a container, keep the resulting solution for 30 minutes until the gelatin granules swell, then heat in a water bath to 60 ° C, then add to the solution add 5 g of phenol and stir until a homogeneous transparent mass is obtained, after which the biomaterial is placed on the bottom of a plastic dish and filled with the prepared gelatin medium, close the dish with a plastic lid and leave until the gelatin medium has completely hardened for 1 hour, then the gelatin block with the enclosed biomaterial is removed from the plastic dishes, maintaining its integrity, after which the biomaterial is ready for examination in a computed tomograph.

After this, the biomaterial isolated and enclosed in a gelatin medium is subjected to CT examination in one of two possible modes:

1. Mode 1 is represented by data collection in the classical mode, similar to data collection in conventional CT in the spiral mode: tube voltage 120 kV, X-ray exposure - 200 mAs, pitch - 0.6, a large focus of the X-ray tube moving at a speed of 1 is used revolution in 0.5 s. This mode is used to obtain images of large objects.

2. Mode 2 is represented by data collection in high-resolution mode: tube voltage 120 kV, X-ray exposure - 60 mAs, pitch - 0.55, uses a small focus of the X-ray tube moving at a speed of 1 revolution per second, which allows you to obtain sections with resolution up to 0.6 mm. This mode is used to obtain high-resolution images of small objects.

EXAMPLE OF EXPERIMENTAL USE OF THE METHOD

Archival museum preparations of amputated lower extremities with vascular pathology were used.

The femur was prepared in the frontal plane at the level of the distal section using a band saw to obtain a cut 5 cm thick, then the biomaterial was washed with 0.9 vol. % sodium chloride solution, then prepared the gelatin medium as follows. 1 liter of distilled water and 60 g of gelatin were placed in a container, the resulting solution was kept for 30 minutes until the gelatin granules swelled, then heated in a water bath to 60°C, after which 5 g of phenol was added to the solution and stirred until a homogeneous transparent mass was obtained, after this, the biomaterial was placed at the bottom of a plastic dish and filled with the prepared gelatin medium, the dish was closed with a plastic lid and left until the gelatin medium completely hardened for 1 hour, then the gelatin block with the enclosed biomaterial was removed from the plastic dish, maintaining its integrity, after which the finished preparation was scanned for computed tomograph in mode 1.

The lower limb was prepared in the sagittal plane at the level of the knee joint using a band saw to obtain a 5 cm thick cut.

Then the biomaterial was washed with 0.9 vol. % sodium chloride solution and placed on the bottom of a plastic dish and filled with gelatin medium prepared as follows. 1 liter of distilled water and 60 g of gelatin were placed in a container, the resulting solution was kept for 30 minutes until the gelatin granules swelled, then heated in a water bath to 60°C, after which 5 g of phenol was added to the solution and stirred until a homogeneous transparent mass was obtained. Cover the dish with a plastic lid and leave until the gelatin medium hardens completely for 1 hour. Then the gelatin block with the enclosed biomaterial was removed from the plastic container, maintaining its integrity, after which the finished preparation was scanned on a computed tomograph in mode 1.

The hand was prepared in a horizontal plane at the level of the bodies of the metacarpal bones using a band saw to obtain a cut 5 cm thick.

Then the biomaterial was washed with 0.9 vol. % sodium chloride solution and placed on the bottom of a plastic dish and filled with gelatin medium prepared as follows. 1 liter of distilled water and 60 g of gelatin were placed in a container, the resulting solution was kept for 30 minutes until the gelatin granules swelled, then heated in a water bath to 60°C, after which 5 g of phenol was added to the solution and stirred until a homogeneous transparent mass was obtained. Cover the dish with a plastic lid and leave until the gelatin medium hardens completely for 1 hour. Then the gelatin block with the enclosed biomaterial was removed from the plastic container, maintaining its integrity, after which the finished preparation was scanned on a computed tomograph in mode 2.

The CT study showed that the gelatin isolation medium was not an obstacle to the CT study. The macroscopic characteristics of the prepared preparations coincided with the radiological data of CT images. Carrying out a CT study allows you to save morphological data on specific preparations for further use in research and scientific exchange, conduct a comparative study of macroscopic and radiological characteristics of the objects being studied, and also identify the presence of features and morphometric characteristics invisible to the eye.

This technique allows for CT examination of individual parts of the body or organs for analysis and comparison of macroscopic and radiological characteristics. Within the framework of this dissection method, a comparative assessment of the features of macroscopic preparations and tomograms is possible, which corresponds to the coincidence of data obtained in the framework of a classical autopsy and information obtained from the analysis of digital images in the framework of virtopsy.

This technique can be used to create atlases and visual teaching aids containing illustrations of both anatomical preparations and tomograms and 3D reconstructions, for the professional training of radiologists, pathologists and forensic experts as part of training in post-mortem radiation diagnostic methods.

Claims (1)

A method of enclosing a biomaterial in a gelatin medium for temporary preservation and subsequent scanning on a computed tomograph, including enclosing the biomaterial in gelatin and characterized in that the biomaterial is washed with 0.9 vol. % sodium chloride solution, then prepare the gelatin medium as follows: place 1 liter of distilled water and 60 g of gelatin in a container, keep the resulting solution for 30 minutes until the gelatin granules swell, then heat in a water bath to 60°C, then add to the solution add 5 g of phenol and stir until a homogeneous transparent mass is obtained, after which the biomaterial is placed on the bottom of a plastic dish and filled with the prepared gelatin medium, close the dish with a plastic lid and leave until the gelatin medium has completely hardened for 1 hour, then the gelatin block with the enclosed biomaterial is removed from the plastic dishes, maintaining its integrity, after which the biomaterial is ready for examination on a computed tomograph.