JP2014176495A - Bed movement control device, movement control method and movement control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bed movement control technique to detect a contact between a medical worker or other object and a bed beforehand and take a measure in order to avoid such a contact.SOLUTION: A bed movement control device 20 has: a derivation unit 21 for deriving a surface shape of each object by detecting reflection of a beam emitted to a floor where objects are present; an identification unit 23 for identifying each object from the surface shape; a calculation unit 24 for calculating a distance between a bed 13 and other object(s) (for example, a worker or a medical table) among the identified objects; and a signal output unit 25 for outputting a response signal on the basis of the calculated distance and a setting threshold.

Description

  The present invention relates to a bed movement control technique for placing a subject and aligning a subject in a space.

In a treatment apparatus using a particle beam, it is required to accurately irradiate the affected part with the particle beam without damaging normal tissue.
Then, the position of the affected part is detected by X-ray or the like, and the treatment is performed by following the procedure of irradiating the detected position with the particle beam.
For this reason, before the start of particle beam irradiation, it is necessary to appropriately adjust the position and angle of the movable bed on which the patient (subject) is placed, and to accurately position the affected part within the irradiation range (for example, Patent Document 1).

On the other hand, in the above-mentioned particle beam therapy, the number of patients per treatment apparatus is large, and in order to improve the treatment efficiency, it is required to shorten the occupation time of the treatment room per treatment.
In order to shorten the occupation time, in the treatment room, a plurality of preparation operations are performed in parallel by a plurality of medical workers in charge of each when the movable bed is aligned.

Thus, in a treatment room crowded with many medical workers, ensuring work safety is required.
As a conventional safety measure, a measure is adopted in which a contact sensor is provided around the bed, and movement of the bed is stopped when contact between an object such as a medical worker or a medical desk and the bed is detected.

Japanese Patent No. 4695231

Conventional safety measures are post-action measures that stop the movement of the bed after contact occurs.
However, stopping the moving bed is uneasy for the patient and may increase the mental and physical burden.
Moreover, the time loss from when the movement of the bed is stopped until the re-movement is started leads to a decrease in the treatment efficiency.

  The embodiment of the present invention has been made in consideration of such circumstances, and a bed movement control technique for detecting a contact between a medical worker or other article and the bed in advance and taking a countermeasure for avoiding the contact. The purpose is to provide.

  In the bed movement control device according to the embodiment of the present invention, a deriving unit for deriving a surface shape by detecting reflection of a beam irradiated on a floor surface on which an object exists, and an identification unit for identifying the object from the surface shape And a calculation unit that calculates a distance between the bed and the other objects among the identified objects, and a signal output unit that outputs a corresponding signal based on the calculated distance and a set threshold value. .

  According to the embodiments of the present invention, a bed movement control technology is provided that takes a countermeasure to detect contact in advance and avoid contact with a medical worker or other article.

The block diagram which shows embodiment of the movement control apparatus of the bed which concerns on this invention. The bird's-eye view of the particle beam treatment room to which the movement control device for a bed according to the first embodiment is applied. The horizontal projection figure of the particle beam therapy room to which the movement control apparatus of the bed which concerns on 1st Embodiment is applied. Explanatory drawing of the particle beam treatment room to which the movement control apparatus of the bed which concerns on 2nd Embodiment is applied. (A) (B) The explanatory view of the method of deriving a horizontal projection image in the movement control device of the bed concerning a 2nd embodiment. The flowchart explaining operation | movement of the movement control apparatus of the bed which concerns on this embodiment.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
As shown in FIGS. 1 and 2, the bed movement control device 20 according to each embodiment includes a deriving unit 21 that detects the reflection of the beam 12 irradiated to the floor surface 11 on which an object exists and derives the surface shape. A generating unit 22 that generates a horizontal projection image (FIG. 3) of the surface shape; an identification unit 23 that identifies an object from the horizontal projection image (FIG. 3); and the bed 13 and the other of the identified objects A calculation unit 24 that calculates the distance to the object (for example, the worker 14 and the medical table 15), and a signal output unit 25 that outputs a corresponding signal based on the calculated distance and the set threshold value are provided. .

The particle beam treatment room (FIG. 2) to which the bed movement control device is applied is a facility for treating a patient by irradiating an affected area with a high-energy charged particle beam emitted from an accelerator.
In order to accurately irradiate the affected area with a particle beam incident from a particle beam irradiation port (not shown), the bed 13 on which the patient is placed needs to be positioned with high accuracy in the space of the particle beam treatment room.
The bed movement control unit 30 moves the bed 13 to an arbitrary position (X, Y, Z) in the particle beam treatment room based on sequence information 26 set in advance, and further rotates it in an arbitrary rotation direction θ. .

In this particle beam treatment room, when the bed 13 is aligned, a plurality of preparatory operations are performed in parallel, and workers 14 and articles (medical table 15 and the like) in charge of each operation are placed on the floor surface 11. Existing.
The illustrated bed 13 is a recumbent bed. However, the bed 13 may be a chair-type bed. If the affected part position is fixed to the bed 13, the bed 13 is appropriately adopted regardless of the restraint posture of the patient. Is done.
The application of the bed movement control device 20 is not limited to the particle beam treatment room.

In FIG. 2, the irradiation axis P of the sensor 10 that detects reflection by irradiating the floor surface 11 with the beam 12 is inclined with respect to the floor surface 11.
In this way, by installing the sensor 10 with the irradiation axis P inclined, the irradiation region of the beam 12 can be widened with respect to the floor surface 11.

However, in this case, since the beam 12 irradiates the object (the bed 13, the operator 14, the medical table 15, etc.) obliquely, the opposite surface where the irradiation is blocked becomes a blind spot region. Then, as shown by a broken line in the horizontal projection image of FIG. 3, there is a case where the entire image of the object cannot be recognized.
In order to reduce the blind spot area that is not recognized in such a horizontal projection image, the irradiation axis P of the beam 12 may be set perpendicular to the floor surface 11 (not shown).

The sensor 10 is provided on the ceiling in the treatment room, and a distance sensor that measures the surface distance of the floor surface 11 and an object (the bed 13, the worker 14, the medical table 15, etc.) is preferably used.
Such a distance sensor irradiates infrared light radially with the irradiation axis P as symmetry, captures the reflected infrared light pattern with a camera far from the irradiation position, and reaches the target surface in accordance with the principle of triangulation. Measure the distance.

In such a distance sensor, as the number of pixels of the camera used increases, the measurement accuracy can be improved or the irradiation range of the beam 12 can be set wider while maintaining the measurement accuracy.
For example, by applying a distance sensor equipped with a high-vision camera, the detection accuracy of an object existing on the floor surface 11 can be improved.

  The sensor 10 that can be applied to the present invention is not limited to the above-described sensor. As long as the surface shape of the object to be derived can be derived, it is appropriately adopted.

Since the surface shape of the object derived by the deriving unit 21 is expressed as three-dimensional volume surface data, it can be converted into a two-dimensional projection image.
As illustrated in FIG. 3, the generation unit 22 generates a horizontal projection image of an object (the bed 13, the worker 14, the medical table 15, etc.) using the surface shape data as XY coordinates parallel to the floor surface 11. .

When the surface shape data in XYZ space coordinates is converted into a horizontal projection image in XY plane coordinates, the area with different height (Z axis) and overlapping the horizontal plane (XY plane) is canceled in the upper area. A horizontal projection image is constructed.
That is, specifically, taking the operator 14 in FIG. 2 as an example, when the surface shape data on the beam irradiation surface 19 is converted into a horizontal projection image of XY plane coordinates, the upper region of the shoulder portion and the lower limb portion are converted. The lower area overlaps.
As shown in FIG. 3, the horizontal projection image of the worker 14 formed in this case is composed of data of the upper surface shape, with the data of the surface shape of the lower leg portion being canceled.

The identification part 23 identifies the area | region which has height with respect to the floor surface 11 as an object among the horizontal projection images shown by FIG.
On the other hand, when a short object is allowed to enter under the bed 13, the identification unit 23 binarizes the surface shape data using a height threshold.
As a result, it is clear that an object with a low height from the floor 11 does not interfere with the moving bed 13, so there is no need to recognize the presence.

Alternatively, by the binarization process of the surface shape data, two objects separated in the vertical direction but having overlapping horizontal projection images can be identified as separate objects.
Of these identified objects, the bed 13 has a known shape and a known position from the sequence information 26, and therefore can be identified from other objects (worker 14 and medical table 15).

The identification unit 23 may replace the identified object with the shape model 29 registered in the database and cause the computation unit 24 in the subsequent stage to calculate the distance between the bed 13 and the object.
In this database, a three-dimensional shape model 29 of an object such as a worker or a medical table existing in the treatment room is registered.

Since the object is a blind spot area other than the beam irradiation surface 19, the horizontal projection image may not accurately reflect the actual shape.
In this case, a shape model 29 corresponding to the whole image is selected from the database based on the horizontal projection partial image obtained from the beam irradiation surface 19 of the object.
As the selection method, the surface shape data derived from the object is compared with the contour of the shape model 29, and the shape model 29 that most closely matches is selected.

Further, in the matching determination process, the arrangement direction of the shape model 29 is also determined.
Then, by replacing the horizontal projection image with the shape model 29, the positional relationship between the bed 13 and the object is more faithfully reproduced.
Note that the identification unit 23 may identify not only an object from a horizontal projection image but also an object by directly applying a three-dimensional shape model from surface shape data of XYZ space coordinates.

The calculator 24 calculates the distance between the bed 13 and other objects (for example, the worker 14 and the medical table 15) among these identified objects.
This calculation of the distance calculates the shortest distance connecting the contour of the identified area of the bed 13 and the contour of the area of the object around it.
If this calculated distance is large, there is no problem, but if it is small, some measures are taken to avoid contact between the bed 13 and surrounding objects.
Further, it is conceivable to take several measures depending on the calculated distance.

The signal output unit 25 outputs a corresponding signal to the bed movement control unit 30 based on the distance calculated by the calculation unit 24 and the set threshold value.
A plurality of values are prepared for the set threshold, and different response signals are output according to the urgency of the contact avoidance action.

Specifically, the corresponding signal is output to the control unit 30 to change the moving speed of the bed 13 or to change the moving range 16 of the bed so as to avoid the object by changing the sequence information 26.
Alternatively, the response signal includes a case where a warning is given to the worker 14 that there is a possibility of contact with the bed 13.
As described above, by evaluating the distance between the bed 13 and the surrounding objects in real time, it is possible to effectively avoid contact of the moving objects (the bed 13 and the worker 14).

On the other hand, since the movement range 16 of the bed 13 is uniquely determined when the sequence information 26 is determined, the range in which the bed 13 may come into contact with the object when the bed 13 starts moving is already It has been decided.
The analysis unit 27 analyzes the movement range 16 of the bed 13 based on the sequence information 26 for moving the bed 13.
In this case, the calculation unit 24 calculates the shortest distance between the outermost periphery of the bed movement range 16 and other objects (the worker 14 and the medical table 15).

By the way, the worker 14 may put the moving bed 13 into the field of view and perform treatment preparation work in the vicinity of the bed 13 while being conscious of avoiding contact.
In such a case, it is not necessary for the bed movement control unit 30 to take measures to avoid contact with the worker 14.

Therefore, the determination unit 28 determines the orientation of the worker 14 identified from among the objects, and the signal output unit 25 outputs different correspondence signals based on whether the bed 13 exists in the orientation of the worker 14. I decided to.
That is, when the worker 14 is facing the direction in which the bed 13 is present, it is determined that there is no need for contact avoidance because the bed 13 is in the field of view of the worker 14.
On the other hand, if the worker 14 is facing in the opposite direction of the bed 13, it is determined that there is a need for contact avoidance because the bed 13 is not in the field of view of the worker 14.

The determination unit 28 extracts the head region and the arm region from the surface shape data of the worker 14, and determines the orientation of the worker 14 from the relative positional relationship between the two regions after horizontal projection.
The head region and the arm region are extracted by performing binarization processing in the height direction based on the registered height of the worker 14, thereby improving the accuracy of the direction determination.
Further, the relative positional relationship between the head region and the arm region is derived based on the position of the center of gravity of the horizontal projection image in each region and the center position of the circumscribed rectangle surrounding the region of the horizontal projection image.

  In this way, in addition to the distance between the bed 13 and the worker 14, the direction in which the worker 14 is facing is also taken into account, so that the moving range 16 and the moving speed of the bed are adjusted according to the situation, and the contact is made. It can be prevented in advance and both safety and work efficiency can be achieved.

(Second Embodiment)
A bed movement control apparatus according to the second embodiment will be described with reference to FIGS. 1, 4, and 5.
In the second embodiment, a plurality of (for example, two) sensors 10a and 10b are provided. Then, the deriving unit 21 derives the surface shape of the object (illustrated worker 14) existing on the floor surface 11 based on a plurality of (for example, two) beams 12 a and 12 b having different irradiation positions.
In addition, since the function of the other component in 2nd Embodiment is the same as the case of 1st Embodiment, the overlapping description is abbreviate | omitted.

As shown in FIG. 5A, there is a case where an object cannot be irradiated in all directions with one beam 12. For this reason, the horizontal projection images 17a and 17b obtained from the respective beams 12a and 12b have a blind spot area.
However, as shown in FIG. 5B, by combining the surface shape data obtained from different directions into a composite image, the surface shapes of the blind spot regions are complemented to each other, and a complete horizontal projection image 18 of the object is obtained. Can be obtained.

In addition, about the area | region where two surface shape data overlap, it replaces with an average value and performs a synthesis process.
Thus, by deriving the surface shape of the object based on the plurality of beams 12, it is possible to faithfully generate horizontal projection images of the plurality of objects arranged in a wide range of treatment rooms.

The operation of the bed movement control device will be described based on the flowchart of FIG. 6 (see FIG. 1 as appropriate).
Bed movement sequence information 26 is preset (S11). Based on the sequence information 26, the bed movement range 16 in the treatment room is analyzed (S12).
In the process of moving the bed 13 based on the sequence information 26, the beam 10 is irradiated from the sensor 10 (S13), and the reflection is detected to obtain the surface shape data of the floor surface 11 and the object existing thereon. It is done.
Further, a horizontal projection image of the object existing on the floor surface 11 is generated from the surface shape data (S14).

Then, the objects (the bed 13, the worker 14, the medical table 15, etc.) are identified from the generated horizontal projection image (S15).
Of the identified objects, the distance (first calculation distance) between the bed 13 and other objects (worker 14 and medical table 15) is calculated (S16), and if this first calculation distance is equal to or less than the first threshold value. (S17 YES), assuming that there is a high risk of contact with the moving bed 13, the first signal is output (S18), and risk avoiding measures such as decelerating the bed movement are taken (S19).

On the other hand, when the first calculation distance is larger than the first threshold (NO in S17), the distance (second calculation distance) between the bed movement range 16 and other objects (worker 14 and medical table 15) is calculated. (S20). It should be noted that the second calculation distance when other objects have already entered the bed movement range 16 has a negative value.
If the second calculation distance is equal to or smaller than the second threshold (YES in S21), it is assumed that the moving bed 13 may come into contact, and a second signal is output (S22) to warn or move the bed. A risk avoidance response such as changing 16 is taken (S21).

  When the second calculation distance is larger than the second threshold (NO in S20), the flow from (S13) to (S21) is performed until the bed movement is completed, assuming that there is no possibility that the moving bed 13 is in contact. Continue (S23).

  According to the bed movement control device of at least one embodiment described above, the contact of the bed is detected in advance by calculating the distance between the bed and other objects one by one from the horizontal projection image obtained by beam irradiation. In addition, effective measures for avoiding contact can be taken.

Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.
The components of the bed movement control device can also be realized by a processor of a computer, and can be operated by a bed movement control program.

  10 (10a, 10b) ... sensor, 11 ... floor surface, 12 (12a, 12b) ... beam, 13 ... bed, 14 ... worker, 15 ... medical table, 16 ... moving range, 17a, 17b ... horizontal projection image, DESCRIPTION OF SYMBOLS 18 ... Horizontal projection image, 19 ... Beam irradiation surface, 20 ... Movement control apparatus, 21 ... Surface shape deriving part (derivation part), 22 ... Horizontal projection image generation part (generation part), 23 ... Object identification part (identification part) , 24 ... Distance calculation unit (calculation unit), 25 ... Corresponding signal output unit (signal output unit), 26 ... Bed movement sequence information (sequence information), 27 ... Movement range analysis unit (analysis unit), 28 ... For workers Determination part (determination part), 29 ... Shape model database (shape model), 30 ... Bed movement control part.

Claims (10)

A deriving unit for deriving the surface shape by detecting the reflection of the beam irradiated on the floor surface on which the object exists;
An identification unit for identifying the object from the surface shape;
A calculation unit for calculating a distance between the bed and the other objects among the identified objects;
A bed movement control device comprising: a signal output unit that outputs a corresponding signal based on the calculated distance and a set threshold value. In the movement control apparatus of the bed of Claim 1,
A generator for generating a horizontal projection image of the surface shape;
The bed movement control device, wherein the identification unit identifies the object from the horizontal projection image. In the movement control apparatus of the bed of Claim 1 or Claim 2,
An analysis unit for analyzing the movement range of the bed based on sequence information for moving the bed;
The bed movement control device, wherein the calculation unit calculates a distance between the other object and the outermost periphery of the movement range. In the movement control apparatus of the bed of any one of Claims 1-3,
A determination unit for determining an orientation of an operator among the identified objects;
The bed movement control device, wherein the signal output unit outputs the corresponding signal based on the orientation of the worker. In the movement control apparatus of the bed of any one of Claims 1-4,
The bed movement control device, wherein the deriving unit derives the surface shape based on a plurality of beams having different irradiation positions. In the movement control apparatus of the bed of any one of Claims 1-5,
The bed movement control device characterized in that the identification unit identifies the object after binarizing the surface shape in the height direction. In the movement control apparatus of the bed of any one of Claims 1-6,
The bed movement control apparatus, wherein the distance is calculated by replacing the identified object with a shape model registered in a database. In the movement control apparatus of the bed of any one of Claims 1-7,
The bed movement control device, wherein the correspondence signal is a signal for changing a moving speed of the bed or a signal for changing a moving range thereof. Deriving a surface shape by detecting reflection of a beam irradiated on a floor surface on which an object exists;
Identifying the object from the surface shape;
Calculating a distance between a bed and other objects among the identified objects;
And a step of outputting a corresponding signal based on the calculated distance and a set threshold value. On the computer,
Deriving a surface shape by detecting a reflection of a beam irradiated on a floor surface on which an object exists;
Identifying the object from the surface shape;
Calculating a distance between a bed and other objects among the identified objects;
A bed movement control program for executing a step of outputting a correspondence signal based on the calculated distance and a set threshold value.

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