JPH0520326Y2 - - Google Patents

Description

[Detailed explanation of the idea] (b) Industrial application fields The present invention is used in the field of medical X-ray photography.

The present invention relates to an X-ray tomography table having an X-ray tomography function.

(b) Prior art An X-ray tomography table with a linear tomography function,
In X-ray fluoroscopic imaging tables, etc., the detection means for tomography deflection angles is such that the drive system that rotates the support that connects the opposing X-ray tubes and the film surface is provided with sections or reflective bands corresponding to the imaging angle. A typical example is a device that detects this using a micro switch or a photo sensor.

The following number of microswitches and photosensors are required because there is a time delay from angle detection to actual radiation of X-rays.

The total is (2 x n x m) + 2 for n types of photographing angles, m types of photographing speeds, straight line reciprocation, and the start and end points of the straight line trajectory.

Further, the number of intercepts or reflection bands is required to be n+2, which is the sum of n types of photographing angles and the start and end points of the straight trajectory.

(c) Problems to be solved by the invention For this reason, performing tomography at any angle requires an increase in the number of these detection instruments, and it is difficult to determine where to install them in terms of space. Furthermore, the conventional method is difficult to implement because it increases the effort required to install and adjust these switches.

The purpose of this invention is to easily detect the set shooting angle without using a micro switch or photo sensor.
Further, to provide an X-ray tomography table that allows tomography at any angle to be easily performed, and in which X-ray radiation is actually performed when the imaging angle is detected, that is, there is no time delay in X-ray radiation. That's true.

(d) Means for solving the problem The above purpose is to
On the radiography table, each unit distance movement of the X-ray tube focal point on the tomographic trajectory is counted.
Counter A is set with a count number corresponding to the distance from the starting point on the trajectory to the maximum imaging angle and determined by the X-ray tube moving speed, and a count number is set corresponding to the distance between the maximum imaging angle and the set imaging angle. Counter B, which corresponds to the delay between the X-ray exposure command and the actual exposure, and which sets a count determined by the X-ray tube movement speed, and outputs the X-ray exposure command when the operation starts, and the set shooting Set the count number corresponding to the distance of the swing angle, and when the operation ends,
A counter D is provided to output a line cutoff signal, and
pulse generating means for outputting a pulse for each unit distance movement by movement of the beam tube focal point on the tomographic trajectory; and counter operation control means for sequentially controlling counter A, counter B, counter C, and counter D using the output pulse. This is achieved by having the following.

(E) Action Distance from the starting point on the orbit of the X-ray tube focal point to the maximum imaging deflection angle predefined by the X-ray tomography table, distance from this maximum imaging deflection angle to the set imaging deflection angle, The distance corresponding to the delay between the X-ray exposure command and the actual exposure determined by the characteristics of the generator and the moving speed of the X-ray tube, and the distance of the set imaging angle are counted for each unit distance traveled. As a method, a count number is determined and set in each counter, and then, when the X-ray tube focal point moves on the orbit, a pulse is output for each unit distance movement, and each of the counters is sequentially operated by this output pulse. . In addition, X
The counter related to radiation exposure delay is configured to output an X-ray exposure command signal to the X-ray generator at the start of its operation, and the counter related to the set imaging angle is configured to output an X-ray cutoff signal at the end of its operation. It is configured to output to an X-ray generator.

(f) Example As an application example, two types of fault velocity (moving speed on the trajectory of the X-ray tube) and fault angle of 5 degrees to 40 degrees (±
2.5 degrees to 20 degrees), the X-ray tube can move from left to right and right to left with respect to the film plane, and the starting and ending points are detected by microswitches.

Figure 2 shows low moving speed and shooting angle of 20 degrees (±
10 degrees), and is a diagram illustrating count settings when the X-ray tube moves from left to right with respect to the film surface.

Note that the dotted line indicates the case where the maximum shooting shake angle of 40 degrees (±20 degrees) is set as the shooting shake angle setting value.

Assuming that each unit distance movement of the X-ray tube focus on the orbit is counted, part A in Figure 2 corresponds to the distance from the starting point on the X-ray tube orbit to the maximum imaging angle of 40 degrees (±20 degrees). It shows the number of counts to be taken, and part B shows the maximum shooting angle of 40 degrees (±20 degrees).
The number of counts corresponds to the distance from the set shooting angle of 20 degrees (±10 degrees), and part C represents the delay from the time the X-ray exposure command is output to the time of the actual X-ray exposure. It is expressed by the number of counts, and the characteristics of the X-ray high voltage equipment or X-ray generator and the X-ray
It is known from the moving speed of the wire tube on its orbit.
Part D represents the number of counts corresponding to the distance of the set shooting angle of 20 degrees (±10 degrees). In this figure, the count numbers in portions B and D vary depending on the set shooting angle of 5 degrees to 40 degrees (±2.5 degrees to 20 degrees). Further, the count numbers in portions A and C vary depending on the moving speed and the round trip of photographing (from left to right or from right to left). The reason why it changes depending on the round trip of photographing is that the detection of the microswitches at the start and end points may not be symmetrical.

FIG. 1 is a block diagram showing one embodiment of the present invention.

When the switch SW1 is turned on to the upper terminal, the counter E10a counts up, and when the lower terminal is turned on, the counter E10a counts down, and the imaging angle (tomographic angle) is displayed each time on the display 10c.When the switch SW1 is turned off, the counter E10a counts down. The swing angle is set.

In this way, the set shooting angle or address becomes the address, and the B part count number and D part count number of the contents are stored in the respective data B and data D storage elements 12.
b, 12d. Further, according to the moving speed and imaging direction signals from the fault travel control circuit 16, the A part count number and the C part count number are set to the data A and data C setting circuits 12a and 12, respectively.
It is set to c. Here, the A part count number is
Since it is affected by whether the tube moving speed is high or low, the data A setting circuit 12a receives the output data of the data A setting circuit 12c, and at the same time receives the output data of the count number setting circuit 18 between the starting point and the maximum shooting angle. is received, and calculations are performed between the two.

Next, the counter A is sent from the fault traveling control circuit 16.
-Each data is set in counters A to D by preset signals to counters D14a to D14d. These count data are as described above.

When the X-ray tube starts traveling on the orbit, the fault traveling amount pulse generating means 20 generates a pulse for each unit distance travel set previously regarding counting,
The signal is input to counters A to D14a to D14d, and first, counter A14a starts counting down.

When the pulse counting for the data A is completed, the counter B14b counts down, and the counting operations are sequentially controlled from the counter A14a to the counter D14d.

In this process, when the counter C14c starts operating, an X-ray exposure command signal is output to the X-ray high voltage device or the The operation starts, that is, at this point, the set imaging angle is detected and tomography starts, and when the counting operation ends, an X-ray cutoff signal is output, and at the same time, tomography ends. At this time, X-ray radiation symmetrical with respect to 0 degrees can be obtained.

Note that an absolute value type encoder may be used as the pulse generating means, and the X-ray start signal may be turned on or off by comparing the coded absolute value of the tomographic travel amount with the coded angle setting circuit.

Alternatively, a potentiometer may be used in place of the pulse generating means, and the X-ray start signal may be turned on or off by comparing the detected voltage proportional to the tomographic travel distance with the voltage set corresponding to the tomography oscillation angle. can.

(G) Effects According to the present invention, it is easy to set and detect any tomographic scanning angle, and in doing so, the number and installation locations of detection parts such as microswitches and photo sensors are limited, and the X-ray The delay in radiation can be eliminated, and X-ray radiation can be symmetrical with respect to 0 degrees.

[Brief explanation of the drawing]

FIG. 1 is a configuration block diagram showing one embodiment of the present invention, and FIG. 2 is an explanatory diagram of an example of setting the count number according to the present invention. 10 is a tomography scanning angle setting circuit, 12 is a preset setting circuit, 14 is a counter, 16 is a tomography travel control circuit, 18 is a starting point and maximum imaging vibration angle count setting circuit, 20 is a tomography travel amount pulse generating means,
22 is an X-ray high voltage device.

Claims (1)

[Scope of utility model registration request] In an X-ray imaging table with an X-ray tomography function, each unit distance movement of the X-ray tube focal point on the movement trajectory is counted, and the distance from the starting point on the trajectory to the maximum imaging deflection angle is counted. Counter A is set with a count determined by the tube movement speed, counter B and X are set with a count corresponding to the distance between the maximum shooting swing angle and the set shooting swing angle.
A counter C that corresponds to the delay between the radiation exposure command and the actual radiation and is determined by the X-ray tube movement speed is set, and the distance of the counter C that outputs the X-ray radiation command when the operation starts and the set imaging swing angle. A counter D is provided for setting a corresponding count number and outputting an X-ray cutoff signal when the operation is completed, and a pulse generating means for outputting a pulse every time the X-ray tube focal point moves on the tomographic trajectory according to the unit distance movement; An X-ray tomography table comprising: counter operation control means for sequentially controlling and operating a counter A, a counter B, a counter C, and a counter D using an output pulse.