RU93019U1 - CALIBRATION MARKERS FOR DETERMINING DENSITY OF BONE TISSUE DURING X-RAY STUDY - Google Patents

Abstract

 Calibration markers for determining bone density during X-ray examination, characterized in that they are made in the form of two objects - in the form of a triangle and a rectangle, each of which consists of at least four fragments of different density and radiopacity.

Description

The device relates to medicine, namely to traumatology and orthopedics and can be used for rapid assessment of tissue density in an x-ray.

Known devices and methods for determining bone density, in particular the "Method of using X-ray morphometry to assess the mineral density of bone tissue of the alveolar bone" (Pat. No. 2320267 of 03/27/2008).

The method proposed by the authors consists in obtaining an x-ray image using a stepwise attenuator, constructing a calibration curve that compares the optical density of the x-ray image with the volume specific concentration of calcium hydroxyapatite in g / cm2. In this case, a step attenuator is made of a copper alloy.

The disadvantages of the method: rather laborious.

The well-known "Method for assessing the mineralization of bone regenerate according to the images of x-rays" (US Pat. 2316255 from 06.20.2006).

For its implementation, the intensity of each pixel of the shadow of the regenerate is determined, the average intensity of the shadows of the soft tissues and the background of the x-ray image at the level of the bone regenerate is additionally measured, the values of which are used to calculate the optical density of the pixels. The obtained variation series of optical density values in the regenerate are analyzed using the method of descriptive statistics and methods for testing statistical hypotheses. The variational row is ranked in increasing order; the optical density range is broken down from 0 to 1.1 cu 22 equal intervals in increments of 0.05 cu The fraction of pixels having an optical density corresponding to each interval in the regenerate area is determined. A histogram of the distribution of optical densities is constructed corresponding to the distribution of structures with varying degrees of mineralization in bone regenerate.

The method requires the use of additional mathematical apparatus and time, which is not always feasible in clinical practice.

A known method of photosensitometry x-ray or their digitized images 2281030 from 09/27/2003

To implement the method, the intensity of the optical density of the air shadow is measured by horizontal and vertical lines, as well as by area and in the absence of a spread in the values of the intensity of optical density of more than 5%, an X-ray image is considered suitable for densitometric analysis. When the scatter in the values of the optical density intensity is more than 5%, the type of image defect is established: in the presence of an air shadow intensity gradient only vertically or horizontally, and also in the presence of an air shadow intensity gradient from the center of the image to the periphery, the x-ray image is conventionally suitable for densitometric analysis. If there is no air shadow on the area unrelated to the presence of gradients along the axes of heterogeneity or in the presence of a combined variant, the X-ray image is considered unsuitable for densitometric analysis.

With this assessment method, there are no clear criteria for the digitally expressed bone density.

The well-known "Method for determining the strength of the spongy bone tissue of the femoral head" (application 2007105413 from 08.20.2008).

The method for determining the strength of the spongy bone tissue of the human femoral head, which consists in the fact that the patient undergoes radiography of the proximal femur in two standard projections using a stepped reference wedge and bone strength is calculated at a specific point of the femoral head according to a special formula.

The method requires the use of additional mathematical apparatus and time, which is not always feasible in clinical practice.

The purpose of creating a utility model is to develop a device that allows fairly accurately assess the density of tissues on an x-ray using calibration scales. The device is easy to manufacture, has a low cost, is available for use in any medical institution equipped with an x-ray room.

The technical result is achieved by creating calibration markers consisting of fragments with a known density of the material.

The figure 1 shows the external of such markers. Markers are a triangle (Fig. 1 A), the shape of which is similar to the letter "L" and a rectangle (Fig. 1 B), whose shape is similar to the letter "P". This form of markers is necessary to distinguish between left-sided or right-sided fragments on the radiograph. In case a picture of a part of the body of the left side of the torso next to the object is placed, a stamp in the shape of a triangle is needed, if you need a picture of a part of the body of the right side of the body next to the object, stamp is placed in the shape of a rectangle.

Markers can be made by, for example, gluing, thermal fitting, mechanical screw connection from fragments having a known material density corresponding to a certain degree of radiopacity. So, in figure 1 (1) a marker fragment with a transmittance of 95% is indicated, 1 (2) with a transmittance of 60%, 1 (3) with a transmittance of 30%, 1 (4) with a transmittance of 5%. We propose using at least four fragments with different radiopaque contrasts in the manufacture of markers. In this case, the graduation scale has a step of about 30% change in density. An x-ray with such markers can be visually evaluated by a doctor with an approximate estimate of the density of the patient’s tissue area of interest in each case. For a more accurate assessment by simple scanning and using standard image processing programs by comparing the percentage of gray on the marker sections and the patient tissue sections of interest, an exact quantitative expression of the density of the tissue region of interest can be obtained. With the method of estimating tissue density using grading markers, the accuracy of the assessment will not depend on the technical characteristics of the solutions used in the development of the images or the specified power of the x-ray machine. The error in the image of the marker will correspond to the error in the image of the patient's tissues.

If necessary, it is possible to produce markers consisting of a larger number of fragments of different densities and radiopaque (figure 2).

Thus, the proposed model is distinguished by the presence of a shape corresponding to the designations of the right and left parts and the presence in one marker of fragments of material of different density and radiopacity. The model is characterized by simplicity, low cost, convenience and affordability.

Designation for the drawings.

Figure 1. General view of calibration markers with a minimum number of fragments.

1 fragment with a transmittance of 95%,

2 fragment with a transmittance of 60%,

3 fragment with a transmittance of 30%,

4 fragment with a transmittance of 5%,

Figure 2. Calibration markers containing 16 fragments

Claims (1)

Calibration markers for determining bone density during x-ray examination, characterized in that they are made in the form of two objects - in the form of a triangle and a rectangle, each of which consists of at least four fragments of different density and radiopacity.