JPH0827355B2 - Radiation receiver - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation image receiving apparatus using radiation in the medical field and industrial field.

2. Description of the Related Art As a configuration of a conventional radiation image receiving device, small semiconductor elements sensitive to radiation are arranged in an array, the number of pulses of radiation quantum output from each element is set as a pixel density, and the array is scanned to obtain a two-dimensional image. Has been proposed, and it has become possible to obtain a radiation image with extremely high sensitivity and high resolution (JP-A-59-94046 and JP-A-59-100885). These methods count the pulses from the radiation-sensitive element array for a fixed time and store them in a memory, and perform the same counting at the next position while sending the element array continuously or stepwise along the object. Thus, a two-dimensional radiation image signal is obtained.

However, in the method as described above, in order to correct the temporal variation of the radiation output of the radiation source, the count data stored in the shared memory is subjected to the calculation correction processing later. Therefore, there is a problem that the processing takes time as a result.

In view of the above point, the present invention provides a radiation image receiving apparatus that enables correction of temporal variation of a radiation source at the same time as data acquisition, eliminates the need for subsequent arithmetic processing, and shortens processing time. With the goal.

Means for Solving the Problems In order to achieve the above-mentioned object, a radiation image receiving apparatus of the present invention comprises a radiation sensitive element array in which small radiation sensitive elements sensitive to radiation are arranged in a line in a straight line or a curved arc, and a radiation source. A radiation sensitive element for a radiation source monitor provided at a position where the radiation from the object is emitted without passing through the subject,
The counting of the output pulse number of the radiation sensitive element for monitoring is started at the same time as the counting of the output pulse number of each element of the radiation sensitive element array is started, and the pulse number from the radiation sensitive element for monitoring becomes a predetermined number. And a means for detecting the count number of the pulse from each element of the element array as the pixel density.

Operation According to the present invention, with the above-described configuration, the counting of the output pulse from each element of the radiation sensitive element array and the output pulse from the monitoring element are simultaneously started, and the number of pulses from the monitoring element reaches a predetermined number. The count number from each element of the element array is detected as the pixel density when it is reached, the element array is transferred to adjacent positions stepwise or continuously, and the same process is repeated to obtain a density signal of a two-dimensional screen.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows an example of the image pickup section of the radiation image receiving apparatus in one embodiment of the present invention. FIG. 2A is a front view of the image pickup section, and FIG. In FIG. 2, 1 is x
The line generation tube, 30 is a bed, and the subject 2 is placed on the bed 30. Reference numeral 3 is an X-ray sensor array, and the element at the outermost end thereof is used as the monitor sensor 20. X-ray generation tube 1
The output X-ray is shaped into a thin fan-shaped X-ray beam by the slit 4 and is applied to the sensor array 3 and the monitor sensor 20, and the data from these sensors is converted into a circuit unit.
Processed by circuitry within 31. The circuit unit 31 in which the sensor array 3 and the monitor sensor 20 are arranged is configured to move along the guide rail 32. For example, the circuit unit 31 moves in the depth direction from the front side in FIG. In FIG. B, it moves from left to right. Then, every time the circuit unit 31 moves stepwise or continuously on the guide rail 32 to the adjacent position, a position detection pulse is output.

FIG. 1 shows an example of a processing circuit section of a radiation image receiving apparatus according to an embodiment of the present invention.
For example, circuits other than the display device 10, the X-ray controller 11, and the mechanism controller 12 are provided inside the circuit unit 31 shown in FIG. The configuration and operation of the circuit shown in FIG. 1 will be described below.

The output of each element of the sensor array 3 is amplified by the amplifier 5 for each element and is input to the counter 7 through the gate circuit 6. The gate circuit 6 is clock-controlled by the output of the flip-flop 27 to pass an input signal,
The timing of prevention is regulated. For example, when the output of the flip-flop 27 is at the high level, the input signal is passed, and when it is at the low level, the input signal is blocked.
Therefore, the pulse output signal from the sensor array 3 is added to the counter 7 only when the output of the flip-flop 27 is at the high level, and the number of pulses is counted. On the other hand, the pulse output signal from the monitor sensor 20 is amplified by the amplifier 21, passes through the gate circuit 22, and is input to the counter 23.
The count value of the counter 23 is compared with the value of the register 25 by the comparator 24. Then, when the count value of the counter 23 becomes equal to the value of the register 25, a pulse is input from the comparator 4 to the R input of the flip-flop 27, the flip-flop 27 is reset, and the output of this flip-flop becomes low level. . That is, the flip-flop 27
Is set by the position detection pulse 26 being input to the S input to open the gates 6 to 22, and the counter 23
Is reset when the number of counts reaches the value set in the register 25, and the gates 6 to 22 are closed. As a result, the gate 6 is always open for a time period during which a fixed number of pulses are output from the monitoring sensor 20, and the intensity of the X-ray emitted from the X-ray tube varies with time. Also always works to substantially correct it. The value of the register 25 is set and controlled by the processing device 9.

The value counted by the counter 7 is latched by the latch 8 after the gate 6 is closed, and each data is input to the processing device 9 as one line of imaging data. The same process is repeated while moving the circuit unit 31, and when the imaged data of the two-dimensional screen is obtained, the processing device 9
Then, for example, filtering processing, scaling processing, gradation conversion processing, and the like are performed, and then the display device 10 displays.

In FIG. 1, 11 is an X-ray control circuit for controlling the amount of X-ray irradiation, and 12 is a mechanism control circuit for controlling the operation of the entire mechanism as shown in FIG. , Both operate by receiving a command from the processing device 9.

In the above description, an example in which a normal X-ray image is obtained has been shown, but the present invention is also applicable to obtaining an image of energy subtraction, for example.

Energy subtraction uses the difference in the radiation absorption coefficient of the subject, and by dividing the radiation that has passed through the subject into those with high energy and those with low energy, information on the constituent substances of the subject, etc. It is possible to obtain more advanced image information as a radiation image.

In that case, for example, the circuit configuration shown in FIG. 3 may be used. That is, the output of the gate 6 may be divided into a high energy pulse and a low energy pulse by the pulse height discriminating circuit 28 and input to the counter 7, and the others are the same as those shown in FIG.

Although the pulse gated by the gate 6 is added to the pulse height discrimination circuit 28 in FIG. 3, the output of the amplifier 5 is divided into high energy pulses and low energy pulses by the pulse height discrimination circuit 28. Alternatively, the gate 6 may be used to apply the voltage to the counter 7.

As described above, in the present embodiment, the element on the outermost end of the sensor array is used as a monitor sensor, and the pulse output detected by this monitor sensor is counted, and the sequential circuit is performed at the timing when this count value becomes constant. By moving the unit, the circuit unit is always moved when a certain amount of incidence is realized, and not only the output fluctuation of the X-ray source but also the deviation between the X-ray beam and the sensor array due to an error in the mechanism or the like. Can be similarly corrected.
Further, there is an effect that it is possible to reduce variations in characteristics between the monitor sensor and each element of the sensor array.

In the present embodiment, the element on the outermost end of the sensor array is used as the monitor sensor, but the monitor sensor does not need to use a part of the sensor array, and its installation location interferes with the subject. If not done, it can be arbitrarily arranged.

EFFECTS OF THE INVENTION According to the present invention, since the element array is moved with a certain amount of radiation incident on the sensitive element for monitoring, the temporal change of the output of the radiation source can be performed simultaneously with the data acquisition. Therefore, the processing time can be greatly shortened and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a block diagram of a processing circuit of a radiation image receiving apparatus according to an embodiment of the present invention, FIGS. 2A and 2B are a front view and a side view showing a configuration of an image pickup unit of the embodiment, and FIG. It is a block diagram of a processing circuit of a radiation image receiving apparatus of another embodiment. 1 ... X-ray generation tube, 2 ... Subject, 3 ... Sensor array, 4 ... Slit, 6,22 ... Gate, 7,23 ... Counter, 9 ... Processing device, 20 ... Monitor sensor , 24 …… comparator, 25 …… register, 27 …… flip-flop.

Claims (1)

[Claims] 1. A radiation sensitive element array in which small radiation sensitive elements sensitive to radiation from a radiation source are arranged in a line in a straight line or a curved arc, and radiation from the radiation source is irradiated without passing through a subject. Radiation sensitive element for radiation source monitoring provided at a position, and a counter for starting counting the number of output pulses of the radiation sensitive element for monitoring and at the same time counting the number of output pulses from each element of the radiation sensitive element array. And an image processing unit that detects, as a pixel density, the count number of pulses from each element of the radiation sensitive element array when the count value of the output pulse number of the monitor radiation sensitive element reaches a predetermined number,
A radiation receiving apparatus, characterized in that the radiation-sensitive element array is configured to obtain a two-dimensional screen density signal while transferring the radiation-sensitive element array to an adjacent position stepwise or continuously.