JPH08280656A - Apparatus for measuring amount of bone-salt for forearm - Google Patents

Abstract

PURPOSE: To solve complication and to shorten measuring time by automating determination of the measuring position in an apparatus for measuring the amt. of bone-salt for a forearm. CONSTITUTION: A plurality of holes 30 for insertion are formed on both sides of a measuring face 24 of a placing stage 22. A proper hole 30 for insertion is selected in accordance with the length of the forearm of an subject to be examined and an elbow rest 32 is inserted into the hole 30 for insertion. The subject to be examined brings his elbow head into contact with the elbow rest 32 under a condition where the elbow is bent approximately at a right angle and places the forearm on the placing stage 22. The forearm length can be measured by fitting a light marker 200 based on the light source 28 for the light marker at a specified position of the wrist and a measuring position can be specified therefrom.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forearm positioning mechanism in a bone mineral content measuring device.

[0002]

2. Description of the Related Art A bone mineral content measuring device is a device for irradiating a human body with radiation (X-rays) and measuring the amount of bone mineral such as calcium contained in bone from its attenuation. For example, it is used for diagnosis of osteoporosis.

The forearm bone mineral content measuring device is intended to measure the forearm between the elbow and the wrist, particularly the radius 10 and the ulna 12 shown in FIG. A conventional forearm bone mineral density measuring device has an X-ray generator built in a lower portion of a mounting table on which the forearm is arranged, while an X-ray generator is disposed above the forearm mounting table at a certain distance.
A line detector is arranged. The X-ray generator and X-ray detector are
A pair constitutes a measurement unit, and the measurement unit is capable of scanning in the front-rear and left-right directions parallel to the surface of the mounting table.

When measuring the amount of bone mineral, first, the subject places his forearm on a mounting table with the elbow of one of his left and right arms bent substantially at a right angle. Then, the measurement unit is moved to a measurement location, and the bone mineral content is measured by X-ray irradiation and detection. The amount of bone mineral can be measured by selecting the mode.
This is executed for the entire forearm or a specific position.

When observing a change in bone mineral content of a person over time, it is necessary to set a measurement position at a predetermined position on the forearm. Conventionally, as shown in FIG.
For example, a reference position 100 where there is a ulnar styloid process (having a protrusion on the epidermis near the wrist) 14 existing at the wrist side tip of the ulna and an olecranon position 102 where the olecranon 16 exists.
If the distance between and is defined as the forearm length L, the forearm length L
The position that internally divides the number into a predetermined fraction (for example, 1/3) is specified as the measurement position 104, and X-ray irradiation and detection are performed at the measurement position 104 to observe the bone mineral content over time (measurement). ) Is done. The measurement position 104 is specified in order to match the measurement conditions, and if the same position is measured for several years, the secular change in the bone mineral content can be examined.
It is also possible to check individual differences.

In the conventional bone mineral density measuring device for forearm,
The measurement position 104 was artificially designated. That is, first, the forearm length L is measured using a large scale or the like as an accessory of the apparatus, and then the forearm is placed on the mounting table. Here, a light source for a light marker is arranged near the X-ray detector above the mounting table, and the light source is provided so that the irradiation light from the light source irradiates the ulnar styloid process 14. Slide the measuring unit. The irradiation light (light marker) from the light source indicates the position where the X-ray is irradiated.

By the above operation, the reference position 1 with respect to the apparatus
00 will be designated (input). In parallel with the above operation, the coordinate of the measurement position 104 (the distance from the ulnar styloid process 14 to the measurement position 104) is artificially calculated from the preset internal ratio and the forearm length L, and the measurement position 104 is calculated. Is entered as a numerical value using the keyboard.

After the above preparations are completed, the ulnar styloid process 14
The measurement unit moves from the existing position to the side of the olecranon 16 and is stopped at the measurement position 104 obtained above,
Bone mineral content is measured. At a later date, when the bone mineral content is measured again or when the measurement is performed on another subject under the same conditions, the series of steps described above is repeated.

[0009]

As described above, in the conventional apparatus, the forearm length L is specified when the measurement position 104 is specified.
And the distance from the ulnar styloid 14 to the measurement position 104 must be input, which is complicated. Therefore, it was not suitable for mass screening.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to automate the specification of a measurement position (particularly, measurement of the forearm length) and to reduce the complexity of bone mineral density measurement. To alleviate.

It is another object of the present invention to appropriately specify the measurement position regardless of the individual forearm length or whether the forearm to be measured is left or right.

[0012]

In order to achieve the above object, the invention according to claim 1 is a mounting table for mounting a forearm,
Bone mineral content measurement including a measurement unit configured with a radiation generator and a radiation detector arranged with the forearm on the mounting table in between, and a scanning mechanism for scanning a measurement position by the measurement unit. In the apparatus, an elbow pad provided on the mounting table and applied to the elbow head of the forearm, reference position designating means for designating a portion of the wrist of the forearm having external characteristics as a reference position, and the elbow pad. The forearm length calculation means for calculating the forearm length based on the position and the reference position, and the measurement position calculation means for calculating a position for internally dividing the forearm length at a predetermined internal division ratio as a measurement position. And

According to a second aspect of the present invention, there is provided elbow rest position adjusting means for adjusting the position of the elbow rest along the longitudinal direction of the mounted forearm.

According to a third aspect of the present invention, there is provided an elbow rest position detecting means for detecting the elbow rest position.

According to a fourth aspect of the invention, a plurality of elbow pad fixing portions are formed at the end of the mounting table along the longitudinal direction of the forearm to be mounted.

According to a fifth aspect of the present invention, a plurality of the elbow pad fixing portions are formed at the left and right ends of the mounting table.

According to a sixth aspect of the present invention, an elbow rest detector for detecting the presence of the elbow rest is arranged for each of the elbow rest fixing portions.

[0018]

According to the structure of the first aspect, the subject's forearm is placed on the placing table in a state in which the olecranon is in contact with the olecranon pad. Then, a portion of the wrist of the forearm having external characteristics is designated as a reference position, and the forearm length calculation means calculates the forearm length based on the position of the elbow pad and the reference position. In other words, according to the present invention, it is possible to automatically recognize the position of the elbow pad by the position of the elbow pad to which the elbow pad is applied, and it is possible to easily recognize the position of the elbow pad and the designated reference position. It is possible to calculate the forearm length. Then, a position where the forearm length is internally divided at a predetermined internal division ratio is calculated as a measurement position. This is also done automatically.

Therefore, since the measurement position can be obtained without directly measuring the forearm length only by designating the reference position, the apparatus can be substantially automated in specifying the measurement position. The radiation from the radiation generator is irradiated at the measurement position thus calculated, the X-ray transmitted through the forearm is detected by the radiation detector, and the bone mineral content is calculated from the detection result.

As described above, according to the present invention, it is not necessary to use a large scale or the like before mounting the forearm on the mounting table, and it is not necessary to input the length from the reference position to the measurement position. Therefore, the complexity of the related art can be significantly reduced.

According to the second aspect of the present invention, since the elbow pad adjusting means is provided, the measurement position is always set even when the bone mineral content is measured for children and adults with different forearm lengths. It is possible to fit within an appropriate range.

According to the third aspect of the present invention, since the elbow rest position detecting means is provided, the elbow rest position is automatically detected to detect the forearm length accurately regardless of the position. It is possible to ask. The operator only needs to adjust the position of the elbow rest so that the measured position falls within the measurement range, and the adjusted position of the elbow rest is automatically determined and provided for calculation of the forearm length.

According to the structure of claim 4, since a plurality of elbow pad fixing portions are formed at the end of the mounting table as the elbow pad position adjusting means, the elbow pad is fixed to any one of the fixing portions. This allows the forearm to be accurately positioned.

According to the fifth aspect of the present invention, since a plurality of elbow pad fixing portions are formed at the left and right end portions of the mounting table, the positions of the left and right arms of the left and right arms can be changed only by changing the positions of the elbow pad fixing portions. Can be used for measurement. In this case, if the elbow pad fixing part is set at the right end on the device body side,
The right forearm can be automatically recognized as the measurement target, and when the elbow pad fixing part is set at the left end, the left forearm can be automatically recognized as the measurement target.

According to the structure of claim 6, since the elbow rest detector is arranged for each elbow rest fixing part, it is possible to automatically recognize which elbow rest fixing part the elbow rest is fixed to. It becomes possible to calculate the forearm length accurately.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a perspective view of a bone mineral content measuring apparatus for forearm according to the present invention. This forearm bone mineral content measuring device is a device that measures the amount of bone mineral in the bone using X-rays.

In FIG. 1, the upper surface of the main body 20 installed on the floor via rollers or the like serves as a mounting table 22, and the forearm of the subject is mounted on the horizontal mounting table 22. . Specifically, one of the arms is placed on the mounting table 22 with the elbow bent at a substantially right angle, and the bone mineral content is measured. A measurement surface 24 formed of a member that transmits X-rays is formed in the center of the mounting table 22. The end of the measurement surface 24 in the X direction in FIG. 1 corresponds to the X-ray scanning range.

On the upper part of the main body 20, there is formed an overarm 26 protruding above the mounting table 22. That is, a space for housing the forearm to be measured is formed between the mounting table 22 and the over arm 26.

An X-ray generator is built in the main body 20,
On the other hand, an X-ray detector that detects X-rays is built in the overarm 26. A measurement unit is configured by the X-ray generator and the X-ray detector, and the measurement unit is capable of scanning in the X direction in FIG. That is, when the X-ray generator is scanned in the X direction by the measurement unit scanning mechanism inside the main body 20,
In conjunction with this, the scan mechanism causes the overarm 2
The X-ray detector in 6 is scanned in the X direction. In this way, the X-ray generator and the X-ray detector are always integrated and scanned in the X direction.

In FIG. 1, an X is formed on the over arm 26.
A light source 28 for a light marker is arranged in the vicinity of the line detector, and the light source 28 forms a fan-beam-shaped irradiation light (light marker) 200. This irradiation light 20
0 indicates that the irradiation point is the X-ray irradiation position,
This light source 28 is also scanned in the same manner as the scanning of the measuring unit described above. Such a light marker is used for specifying a reference position, which will be described later. The X-ray generated by the X-ray generator has a pencil beam shape and is detected by the X-ray detector. Of course, the X-rays may be fan-beam-shaped or cone-beam-shaped, and accordingly, the X-ray detector incorporated in the overarm 26 has a one-dimensional X-ray detection element,
Alternatively, they may be arranged two-dimensionally, and if such a configuration is adopted, the measurement time can be shortened. further,
It is also possible to incorporate an X-ray generator in the overarm 26 and an X-ray detector in the other body 20.

As shown in FIG. 1, in this embodiment, a plurality of insertion holes 30 are formed at the left and right ends of the upper surface of the mounting table 22 along the X direction. The insertion hole 30 functions as a fixing means for the elbow pad 32 standing upright on the mounting table 22, and a plurality of the insertion holes 30 are formed in the X direction, so that the position adjusting means for the elbow pad 32 is provided. It is configured. This is because the length of the forearm differs between individuals, so that the measurement position is set to the substantially central portion regardless of the length of the forearm.

As shown in FIG. 4, each insertion hole 30 is provided with a pair of a light emitting element 34 and a light receiving element 36. The light of the light emitting element 34 passes through the internal space of the insertion hole 30 and is detected by the light receiving element 36. Therefore, elbow pads 3
When the protrusion formed on the lower part of 2 is inserted into the insertion hole 30, the light from the light emitting element 34 is blocked and is not detected by the light receiving element 36.
It becomes possible for the main body 20 side to recognize whether or not the elbow pad 32 has been inserted into the. The fixing mechanism of the elbow pad 32 is not limited to that of the present embodiment, and other engaging mechanism or the like may be adopted. Alternatively, the elbow pad 32 may be slidable in the X direction. In any case, it is desirable to provide a means for detecting the position of the elbow pad 32.

In the present embodiment, the contact surface of the elbow pad 32 is simply formed as a flat surface, but a curved contact surface may be formed on the elbow side, for example. The contact surface preferably has a certain degree of hardness in order to improve the recognition accuracy of the olecranon position.

Incidentally, a plurality of types of elbow pads 32 for children and adults may be prepared so that they can be freely exchanged according to the subject.

FIG. 2 shows the principle of measuring the forearm length L in the forearm bone mineral content measuring apparatus of this embodiment. As shown in FIG. 2, since the elbow head 16 is positioned by the elbow pad 32 in this embodiment, first, the elbow pad 32 is placed on the device side.
It is possible to recognize the position of the olecranon 16 as the position of. In addition, the light marker 20 formed by the light source 28
If the measurement unit equipped with the light source 28 is moved so that 0 is aligned with the ulnar styloid process 14, the reference position 10 on the device side is set.
It becomes possible to recognize 0. In the device of this embodiment,
First, with the position 102 of the olecranon 16 recognized, the distance a from the one side 24A of the measurement surface 24 to the olecranon position 102 is calculated, and with the reference position 100 recognized,
The distance b from the reference position 100 to the one side 24A is calculated. Then, after these distances a and b are obtained, a + b is calculated and the forearm length L is obtained.

In this embodiment, as shown in FIG. 1, four insertion holes 30 are formed on each of the left and right sides of the measurement surface 24. Since the irradiation range defined by the measurement surface 24 has a certain width, it is possible to measure the bone mineral content for almost all subjects by such four-step adjustment.

As is apparent from the above description, the main body 2
0 has a built-in arithmetic and control unit composed of a microcomputer and the like. The arithmetic and control unit recognizes the elbow rest position,
Comprehensive control such as calculation of forearm length and measurement position
Perform an operation. Further, the main body 20 has a built-in internal division ratio memory, and the internal division ratio memory has a plurality of internal division ratios (1 /
(10, 1/6, 1/3, etc.) are stored as numerical values. These internal division ratios can be arbitrarily selected by a predetermined selection operation.

Next, a method for measuring the amount of bone mineral in the forearm will be described with reference to FIG.

First, in S101, the body shape of the subject,
That is, the position of the elbow pad 32 is adjusted according to the length of the forearm. In S101, the position of the elbow pad 32 may be adjusted so that most of the forearm fits within the measurement surface 24. At this time, the arithmetic control unit described above determines which insertion hole 30 the elbow pad 32 is inserted into, and thereby the position of the olecranon is automatically specified.

In this embodiment, since a plurality of insertion holes 30 are formed on both sides of the measuring surface 24, there is no restriction on the forearm to be measured.

In S102, the subject places his forearm on the mounting table 22. Specifically, the forearm is placed on the mounting table 22 with one of the left and right arms extended forward and the elbow bent at a substantially right angle. In that case, the elbow head is brought into contact with the elbow pad 32, and the forearm is positioned along the X direction.

Next, in S103, the measurement unit is moved by the operation of the operator, and the light marker 20
The measuring unit is positioned so that 0 illuminates the ulnar styloid process 14. That is, such an operation is performed to capture the reference position.

Since the olecranon position and the reference position are fetched by the above steps up to S103, the forearm length L is calculated based on them in S104. That is, as shown in FIG. 2 or 5, the reference position 100 and the olecranon 102
The distance L between and will be calculated.

Then, in step S105, the measurement position 104 for internally dividing the forearm length L at a predetermined ratio is calculated based on the internal division ratio selectively read from the internal division ratio memory. Specifically, as the distance from the reference position 100, the measurement position 1
04 is specified.

In S106, the measuring unit on the reference position 100 is moved to the measuring position 104, and S1
At 07, X-ray irradiation and X-ray detection are performed, and the bone mineral content is measured.

As described above, according to this embodiment,
It is possible to almost automatically specify the measurement position 104 simply by aligning the light marker 200 with the ulnar styloid process 14 having the external feature on the wrist of the forearm. Therefore, it is possible to eliminate the complexity of measuring the forearm length L using a large scale or the like before placing the forearm on the mounting table 22 as in the related art. Further, from the reference position 100 to the measurement position 104
There is no need to enter the distance to using a keyboard. Therefore, the conventional problems can be greatly improved with a simple configuration.

The method of detecting the position of the elbow pad 32 is not limited to the above-mentioned method, and a switch mechanism or the like may be used. Further, based on whether the elbow pad 32 is placed on the right side or the left side with respect to the measurement surface 24, the measurement unit is moved in advance to the side opposite to the elbow pad, and the light marker 200 is set on the ulnar styloid process 14. You may make it operate as close as possible from the beginning. Furthermore, although the ulnar styloid process 14 is used as the part for specifying the reference position in the above embodiment, another part may be used as the reference position.

[0049]

As described above, according to the present invention,
When measuring bone mineral content for the forearm, the complexity can be reduced,
Moreover, the measurement time can be shortened. Further, according to the present invention, even if there is an individual difference in forearm length, the measurement position can be appropriately specified regardless of whether the forearm to be measured is left or right.

[Brief description of drawings]

FIG. 1 is a perspective view of a forearm bone mineral content measuring device according to the present invention.

FIG. 2 is an explanatory diagram showing the principle of measuring the forearm length L.

FIG. 3 is a flowchart showing steps of measuring bone mineral content for a forearm.

FIG. 4 is an explanatory diagram showing a method of detecting an elbow pad.

FIG. 5 is an explanatory diagram showing how to specify a measurement position.

[Explanation of symbols]

20 main body, 22 mounting table, 26 overarm, 2
8 light source for light marker, 30 insertion hole, 32 elbow rest, 100 reference position, 102 olecranon position, 104 measurement position.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Toho 6-22-1, Mure, Mitaka City, Tokyo Aloka Co., Ltd.

Claims (6)

[Claims] 1. A mounting table on which a forearm is mounted, a measurement unit including a radiation generator and a radiation detector arranged with the forearm on the mounting table therebetween, and a measurement position by the measurement unit. In a bone mineral content measuring device including a scanning mechanism for scanning, an elbow pad provided on the mounting table and applied to the olecranon of the forearm, and a site having external characteristics on the wrist of the forearm as a reference position. A reference position designating means for designating, a forearm length calculating means for calculating a forearm length based on the position of the elbow pad and the reference position, and a position for internally dividing the forearm length at a predetermined internal division ratio. A forearm bone mineral content measuring device, comprising: 2. The forearm bone mineral content measurement according to claim 1, further comprising elbow rest position adjusting means for adjusting the position of the elbow rest along the longitudinal direction of the forearm to be placed. apparatus. 3. The forearm bone mineral content measuring device according to claim 2, further comprising an elbow rest position detecting means for detecting the elbow rest position. 4. The forearm bone according to claim 1, wherein a plurality of elbow pad fixing portions are formed at an end of the mounting table along the longitudinal direction of the mounted forearm. Salt content measuring device. 5. The forearm bone mineral content measuring device according to claim 4, wherein a plurality of the elbow pad fixing portions are formed at the left and right ends of the mounting table. 6. The forearm bone mineral content measuring device according to claim 5, wherein an elbow rest detector for detecting the presence of an elbow rest is arranged for each of the elbow rest fixing parts.