JPH0616777B2 - Bed control device in CT device - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a bed control device in a CT (Computed Tomography) device.

[Technical background of the invention]

The bed in the CT apparatus is a host computer, a bed moving means for moving the bed based on a command from the host computer, and movement of the bed (movement direction and movement amount).
Is detected, the detection result is converted into a digital signal and is sent to the host computer, and its position is controlled by using the movement detection means, whereby the clinical application range can be further expanded. The means described above can be configured by making full use of known techniques such as a servo system and a rotary encoder, and is used in many CT devices. Incidentally, in the field of X-ray CT apparatus, which is a typical example of CT apparatus, generally, the X-ray optical system is fixed at a fixed position (that is, not rotated), and the bed is moved in a direction perpendicular to the X-ray irradiation direction. Imaging is performed by a method of obtaining an X-ray transmission image by performing imaging as in normal X-ray imaging. This method is called Sukianographi or Sukianoscope. With such a device, ROI (Region of Interest) can be obtained on the Sukiyano image.
Depending on the setting of (e [region of interest]), it is possible to plan in advance at which position the image will be taken next, or to move the bed directly to the position specified by ROI. By measuring the angle, angle, etc., the anatomical shape can be recognized with high accuracy.

By the way, when planning the next shooting position by setting ROI on the Sukiyano image or moving the bed to the position specified by ROI, the position recognized by the host computer side and the actual bed It is necessary to match the position of. On the other hand, clinically, it is usual to image only a specific part of the human body, so a mark is placed on a place that is easy to understand anatomically, and a coordinate system (that is, a local coordinate system) is used as the origin. In many cases, the position is displayed and recognized. In order to meet such clinical demands, many CT devices are equipped with "position clear switch" so that the "position display value" can be set to zero at any position. is there.

Here, a specific configuration of the bed control system in the conventional CT apparatus will be described with reference to FIG. In the figure, reference numeral 1 is a bed, and a table 1a on which a patient is placed, and a motor 1b for vertically moving the table 1a vertically (horizontal movement and horizontal movement are performed by separate motors). In some cases), the movement of the top 1a (horizontal movement in the example shown in FIG. 3) is detected, and the position detection means (rotary encoder or the like) for converting the detection result into a digital signal. ) 1c and a bed operating portion 1d for operating the bed from the outside. 2 is a bed control unit,
It controls the bed and also functions as an interface between the bed 1 and the host computer. In addition to the control circuit 2a, the bed control unit 2 has a built-in counter 2b for counting the output pulses of the position detecting means 1c.

In addition, the bed operating section requests the movement of the tabletop by using the switches SW1 and SW2. A switch SW3 having at least an indicator D4 for displaying the current position and having the role of zeroing the current position in order to meet the clinical demand that the local coordinate system is used. It is generally equipped with. In addition, the scanner section 3 and the host computer 4 are included in the CT apparatus.

[Problems of background technology]

By the way, in the conventional bed control device shown in FIG. 3, there is only one counter 2b for counting the output pulses of the rotary encoder which constitutes the position detecting means, and the clear switch SW of the bed operating section 1d.
When 3 is operated, the counter 1b is cleared to 0 (Originally, the clear switch SW3 plays a role of setting the current position to 0. Therefore, when the clear switch SW3 is operated, the counter 1b becomes 0. It goes without saying that). Therefore, for example, if this clear switch SW3 is operated after Sukiyano shooting, the positional relationship between the value recognized by the host computer side and the Skyano image is destroyed, and the shooting position setting (plan) and setting on the Skyano image is set. There was a problem that it was impossible to move the bed to the position, rather than hindering it.

[Object of the Invention]

The present invention has been made to solve the above-described problems, and the current position clear function and the clear operation for responding to a clinical request while detecting the actual position of the bed by the position detecting means are executed many times. Even if it is done, it is an object to meet a request which is conventionally contradictory to have a function of executing various processes on a scan image without any trouble.

[Outline of Invention]

In order to achieve the above-mentioned object, the present invention provides a table for the bed, means for moving the table, motion detecting means for constantly detecting the movement of the table, and when the table reaches one movement limit point, Is provided with a limit sensor for detecting that the bed and an operating section for operating the bed to perform a desired operation, and the bed control circuit for controlling the bed has a counter for counting the output pulses of the motion detecting means and the bed. A register for holding the reference position is provided, and when the top plate reaches one of the movement limit points, the limit sensor operates to clear the register value to "0" and set the counter to the predetermined value. After that, the counter value changes according to the movement of the tabletop, and when a request to clear the display value is made from the operation unit, the counter value at that time is added to the register value. After recording in the register, the counter is cleared to "0", and the value obtained by adding the counter value and the register value is used as the position information indicating the position of the table on the absolute coordinate system. It is characterized by that.

Example of Invention

 The present invention will be described below with reference to the illustrated embodiments.

FIG. 1 shows an embodiment of the present invention. This embodiment has many parts in common with the conventional example shown in FIG. 3, and the common parts are denoted by the same reference numerals as those used in FIG. 3 in FIG. 1 and the description thereof is omitted. Only characteristic parts will be described.

A limit sensor 1e is turned on when the top 1a of the bed 1 reaches the movement limit point, and plays a role of sending a detection signal to the bed controller 2. That is, the top plate portion 1 of the bed 1.
There must be a limit point where a cannot be moved further in that direction when it is moved in a certain direction, and when the top 1a of the bed 1 reaches that limit, The first characteristic point is that the limit sensor 1e can be used for detection.

2c is a register (register) provided in the bed control unit 2 and 2a is an arithmetic control circuit. The bed control unit 2 of the CT apparatus shown in FIG. 1 has a control circuit 2a and a counter 2b.
In addition to the above, a register 2c is provided, and the control circuit 2a clears the value of the register to "0" by the signal of the limit sensor when the top reaches one movement limit point and records a constant value in the counter, After that, the counter is updated according to the movement of the tabletop, and when a request to clear the position display value is issued from the operation unit, the value obtained by adding the counter value to the register value is recorded in the register and then the counter value Is different from the bed control unit 2 of the CT apparatus shown in FIG. 3 in that it has a function as a control means for performing a simple calculation as well as a control for clearing "0" to "0". This is the second
Is the characteristic point of.

Although not shown in FIG. 1, not only the host computer side can input / output to / from the counter 2b, but also the register 2c can be input / output. ing. This is the third characteristic point.

Next, the operation will be described with reference to FIG. FIG. 2 exemplifies how the position of the top plate 1a, the value of the counter 2b, and the value of the register 2c are changed by an operation from the outside in order to clarify the action.

Step0: When the bed system starts up (when the power is turned on, etc.), it is caused by a command from the host computer. Must be moved to). Then, at the timing when the limit sensor 1e is turned on, "0" is set in the receiver 2c and a preset value "B ₀ " is set in the counter 2b.
To set. It should be noted that the value of B ₀ may be any value as long as it is uniquely determined by the bed / host system, and naturally B ₀ = 0.

Step 1: The top 1a is actually moved from this step, but for convenience of explanation, it is assumed that the direction of the top movement is positive in the right direction and negative in the left direction.

First, it is assumed that the tabletop is moved leftward by a distance l ₁ . Then, the counter value will be "B ₀ -l ₁ ".
Let this value (B ₀ −l ₁ ) be B ₁ (B ₁ = B ₀ −
l ₁ ).

However, the value of the register does not change at all.

Step 2: Next, move the top plate to the right by a distance l ₂ .
Then, the counter value becomes “B ₁ + l ₂ ” (this is referred to as B ₂ ). However, the register value does not change.

Step 3: Here, it is assumed that the clear switch SW3 is pressed. Since the clear switch SW3 is simply pushed, the bed position remains the same as in Step 2.

When the clear switch SW3 is pressed in this manner, the old value (= 0) of the register 2c is first set to the counter value "B".
₂ ”is added, and then“ 0 ”is set in the counter 2b (note that B ₃ ≡0).

Step 4: Further, it is assumed that the flat plate is moved leftward by a distance l ₃ . Then, although does not change the value of the likewise register 2c as in Step1, the counter value is _{"0-l 3" = "} - l 3"
(This is designated as B ₄ ).

Step 5: Further, it is assumed that the top board is moved to the right by a distance l ₄ . Then, although the register value does not change, the counter value becomes “B ₄ + l ₄ ” (note that B ₄ + l ₄ is B ₅ ).

Step 6: It is assumed that the clear switch SW3 is pressed again.
Since the clear switch SW3 is merely pushed, the top plate position remains the same as in step 5.

Again, as in Step 3, the register 2c
The value obtained by adding the counter value B ₅ up to that time to the old value (B ₂ ) of is stored, and then “0” is set in the counter 2b.

From the above, the operation of the present invention can be summarized in the following three points.

(1) It is possible to automatically perform the warm-up operation to move the top plate to one end when the system is started up without operator intervention, clear the register 2c to "0", and set the constant to the counter 2c. it can.

(2) When the top board is moved, the value of the counter 2b is updated according to the movement, but the value of the register 2c does not change.

(3) When the clear switch SW3 is pressed, the counter value up to that point is added to the register 2c, and "0" is set to the counter 2b.

The values of the counter 2b and the register 2b can be input to the host computer 4.

Then, in each step of the operation shown in FIG.
How many times the sum of the register value and the counter value is cleared
Even if the switch is operated, the register 2c always indicates the position on the absolute coordinate system of the table 1b with a certain fixed point on the bed 1 as the origin. Therefore, when recognizing or specifying the bed position on the host computer side, the value obtained by adding the register value and the counter value is always used instead of the value of the counter 2c (the position of the top plate on the absolute coordinate system). The necessary processing can be performed by converting the position into the coordinate system. Therefore, the value of the counter 2b can be cleared by operating the clear switch SW3 in order to meet the clinical demand so that the position of the tabletop on the local coordinate system is always recorded in the counter 2b. In addition, by providing the register 2c for accumulating the value of the counter 2b at the time of operating the clear switch SW3, the position of the top plate on the absolute coordinate system can be always grasped.

Although the horizontal movement of the bed top is controlled in the above embodiment, the present invention can be similarly applied to the height control of the top. Further, although the rotary encoder is used as the position detecting means for detecting the movement of the bed in the above-mentioned embodiment, other means may be used.

〔The invention's effect〕

As described above, according to the present invention, even if the operator sets a new coordinate system (local coordinate system) with an anatomically easy-to-understand position as the origin, in the bed control system, the absolute coordinate system is used. Position recognition and position designation can be performed without any trouble.

[Brief description of drawings]

FIGS. 1 and 2 are for explaining one embodiment of the present invention. FIG. 1 is a block diagram of the apparatus, FIG.
FIG. 3 is a block diagram of a conventional bed control device. 1 ... bed, 1a ... top plate, 1b ... means for moving the top plate, 1c ... motion detecting means, 1d ... operating section, 1e ...
... limit sensor, 2 bed control circuit, 2a arithmetic control circuit, 2b counter, 2c register, 3
…… Skyana club, 4 …… Host computer.

Claims (1)

[Claims] 1. A tabletop, means for moving the tabletop, means for detecting movement of the tabletop, limit sensor and bed for detecting when the tabletop reaches one movement limit point. The operation unit for operating the table, the counter for counting the output pulses of the means for detecting the movement of the tabletop, the register for holding the reference position of the bed and the tabletop have reached one of the movement limit points. The register value is cleared to "0" by the limit sensor signal at this time, the constant value is recorded in the counter, and then the counter is updated according to the movement of the tabletop, and the position display value clear request from the operation unit is requested. And a control means for recording the value obtained by adding the value of the counter to the value of the register in the register and then clearing the value of the counter to "0".