JP4785254B2 - Radiography equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radiation imaging apparatus that obtains a radiation intensity distribution, that is, a so-called radiation image, by irradiating a subject with radiation and passing through the subject.
[0002]
[Prior art]
Usually, in a medical facility, it is rare that a dedicated radiographic apparatus according to an imaging region is introduced. In particular, in photographing represented by the screen / film method called general photographing, photographing various parts with a single photographing device is routinely performed. It is important to note that radiography is harmful to the human body. Therefore, the radiation is irradiated only to the region of interest by adjusting the irradiation field stop attached to the front surface of the radiation source such as a radiation tube by the hand of an engineer according to the imaging region. The irradiation field stop is adjusted according to the patient's physique as well as the imaging region.
[0003]
In this way, it is a general restriction of the irradiation field, but it requires adjustment by the engineer for each shooting, so when shooting several tens to hundreds of people every day In this case, it is a very troublesome work that hinders the efficiency of the photographing work. Due to such circumstances, an automatic aperture mechanism in which the irradiation field aperture is interlocked with the size of the imaging region represented by the film size may be introduced. This means that the technician selects the film size (imaging area) according to the patient's physique and imaging region, and the irradiation field stop automatically operates in conjunction with it. In addition, when performing chest imaging as seen in group screening, it is necessary to change the imaging size based on the lower jaw or shoulder of the patient as the imaging area. In this case, when the imaging size is changed in accordance with the patient's physique, the center of the imaging area fluctuates up and down in conjunction with the imaging size. The irradiation field center interlocking mechanism also moves the center of the imaging region in accordance with the automatic aperture mechanism described above.
[0004]
[Problems to be solved by the invention]
The automatic diaphragm / irradiation field center interlocking mechanism is provided on the radiation generator side, and an interface for controlling these is provided on the imaging apparatus side. This interface differs depending on the generator manufacturer or the type of the generator, and it has often been necessary to design a new interface and control software on the photographing apparatus accordingly.
[0005]
In addition, since the conventional screen film method has a standardized dimension called film size, it is sufficient to use this dimension for automatic aperture and field center interlocking. However, in recent years, a technique for acquiring a digital image using a photoelectric conversion device in which pixels composed of minute photoelectric conversion elements, switching elements, and the like are arranged in a lattice form as an image receiving means has been developed and put into practical use. In these apparatuses, the concept of conventional film size does not exist. Since only a portion for controlling the image receiving means can be selected, a free photographing area can be selected. Therefore, the irradiation field size and the irradiation field center position need to be set with a higher degree of freedom than before.
[0006]
[Means for Solving the Problems]
The present invention is a radiation imaging apparatus having the following configuration.
[0007]
In order to achieve the above-described object, the imaging region can be changed, and an imaging unit that obtains a radiation image by converting the intensity of radiation into an electrical signal by a radiation imaging device including a plurality of photoelectric conversion elements;
A plurality of imaging areas of the imaging means and a control table for recording a distance between the center of each imaging area and the center of the maximum imaging area in the image receiving unit of the imaging means as a radiation field center;
A signal for controlling the diaphragm in accordance with the reception form of the tube interlocking input I / F by referring to the control table using the actual size of the image receiving unit of the imaging unit and the actual size of the center of the irradiation field input from the input unit as indexes. And interlocking condition setting means for changing and outputting a signal for controlling the position of the radiation tube,
Based on the signal output from the interlocking condition setting means, a diaphragm driving means for driving an irradiation field stop for restricting an irradiation range of radiation emitted from the radiation tube, and a tube moving means for changing the position of the radiation tube emitting radiation. Tube interlocking control means for irradiating radiation to the imaging region and the corresponding irradiation center by controlling
It is characterized by having.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 schematically shows a radiographic apparatus according to the first embodiment of the present invention. In FIG. 1, reference numeral 10 denotes a radiation tube capable of emitting radiation in the form of pulses, and the radiation control means 15 controls on / off of the radiation pulses, tube voltage, and tube current. The tube moving means 12 refers to a drive unit such as a motor attached to a suspender that supports the radiation tube 10 and changes the spatial position of the tube.
[0012]
Reference numeral 11 denotes an irradiation field stop that regulates the radiation range so that the radiation emitted from the radiation tube 10 is radiated to a region that matches the physique of the subject 17 and the imaging region. Further, the aperture driving means 13 refers to a driving unit such as a motor attached to the irradiation field aperture 11 for changing the radiation irradiation range. In general, a portion surrounded by a dotted line in the figure is generally referred to as a radiation generator.
[0013]
The emitted radiation passes through the subject 17 and reaches the imaging means 18. The amount of transmitted radiation varies depending on the internal configuration of the subject 17 and includes image information thereof. For this reason, a screen / film system is used for the imaging means 18 to reflect the intensity of transmitted radiation as the degree of film blackening, or the intensity of transmitted radiation is electrically generated by a radiation imaging device comprising a plurality of photoelectric conversion elements arranged in a matrix. A radiographic image is obtained by converting it into a signal and reflecting it as digital data by A / D conversion.
[0014]
The tube interlock input I / F 16 is an I / F unit that inputs a signal for controlling tube interlock from the outside, and receives a signal for controlling the aperture and a signal for controlling the tube position. Is delivered to the tube interlocking control means 14. Further, the gantry supporting the imaging unit 18 is provided with a position detection unit 19 such as a potentiometer, and its output is input to the tube interlocking control unit 14. When the imaging means 18 is moved up and down in accordance with the physique (here, height) of the subject 17, the output of the position detection means 19 varies. The fluctuation of the signal is detected by the tube interlocking control means 14, and the radiation tube 10 is moved by controlling the tube moving means 12 so that the radiation center is always constant according to the fluctuation. At this time, what is required is information relating to the position of the radiation irradiation center relative to the imaging means 18. In photographing in a standing position such as the chest, the photographing size is changed based on the patient's lower jaw or shoulder as the photographing region. When the imaging size is changed in accordance with the patient's physique, the imaging area changes with the upper end of the imaging means 18 as a base point, and the center of the imaging area changes up and down in conjunction with the imaging size. That is, information such as which position is the irradiation center is always required, and this also needs to be input from the tube interlocking input I / F 16.
[0015]
As described above, the configuration is a mechanism that is also found in a conventional radiation generator, but in this embodiment, there is a characteristic in the process until a signal is given to the tube interlocking input I / F 16.
[0016]
FIG. 2 is a schematic diagram of a general tube-linked input / output I / F. The tube interlocking output I / F 23 includes relays RL1 to RL6. By driving this relay, the light emission side of the photocoupler on the tube interlocking input I / F16 side is driven, and SIG1 to SIG6 are output. The tube interlocking control unit 14 moves the tube moving unit 12 and the aperture driving unit 13 based on the received drive states of the SIGs 1 to 6.
[0017]
Assume that there are radiation generators A and B. The tube interlocking input I / F 16 provided in these two devices is the driving state of SIG1 to SIG4 for each size of 35 cm × 43 cm, 43 cm × 35 cm, and 35 cm × 35 cm, and the irradiation field center assigned to SIG5 and 6 Is defined as shown in FIG. 3. The offset value in the figure is defined here as a value that is + upward and − downward, with the vertical center of the maximum imaging area in the image receiving unit of the imaging means 18 as a base point.
[0018]
In this case, in order to accurately connect the imaging means 18 to each generating device, the signal output from the tube interlocking output I / F 23 must be adapted to each generating device. For this reason, a tube-linked output for each generator is obtained by the following method.
[0019]
First, parameters relating to tube interlock are input by the interlock condition input means 20. The parameters input here deliver the actual dimensions at the image receiving unit. By making this part an actual size, the interlocking condition input means 20 or the hardware and software (not shown) positioned higher than the interlocking condition input means 20 will have an effect regardless of the lower order configuration. No need to redesign hardware and software for each radiation generator connected. Further, in a conventional system that does not have a restriction of film size, it can be said that it is an indispensable parameter form in order to be able to select a free shooting area.
[0020]
The interlocking condition setting means 21 refers to the control table 22 using the inputted actual dimension as an index. This control table 22 shows the operation defined in FIG. 3, and is stored as, for example, drive bit patterns of SIG1-6. The control table 22 is written in a mask ROM, for example, and can be changed by replacing it on an IC socket, or written in a FLASH ROM or NVRAM. The tube-linked input I / F 16 of the radiation generating apparatus can be changed by a method such as rewriting by a method such as the above, or a form written in a file format on a hard disk and can be changed by editing or rewriting the file. It can be changed according to the form.
[0021]
Assume that the imaging means 18 is connected to the generator A. At this time, the contents corresponding to the generator type A in FIG. In the shooting preparation operation, the imaging unit 18 gives the interlocking condition corresponding to the imaging mode to be performed from the interlocking condition input unit 20 to the interlocking condition setting unit 21. For example, if the imaging means is a film changer using a screen / film, the interlocking condition input means 20 is a DR using a radiographic imaging device comprising a selection button of a magazine containing a film to be used and a photoelectric conversion element. In the case of a system, this indicates a unit for setting the imaging operation (for example, an operation panel to which part parameters are assigned) or a unit for inputting aperture / offset information used for direct imaging. The setting means 21 is given.
[0022]
Here, it is assumed that a parameter of 35 cm × 43 cm in length and width is given by the above operation. The interlocking condition setting means 21 obtains the driving condition of the tube interlocking output I / F 23 corresponding to the received parameter by referring to the control table 22. From the control table 22, the corresponding drive conditions are SIG1 = ON, SIG2 = OFF, SIG3 = OFF, SIG4 = ON, and if the irradiation field center position is given +35 mm, SIG6 = ON. By driving the tube interlocking output I / F 23 according to this, a required signal output is performed with respect to the tube interlocking input I / F 16 of the type A radiation generator.
[0023]
Next, the imaging means 18 is connected to the generator B. At this time, the contents corresponding to the generator type B in FIG. According to the same operation as in the case of the generator type A described above, assuming that parameters of 35 cm × 43 cm in length and width and irradiation field center position + 35 mm are given, driving conditions SIG1 = ON, SIG2 = ON, SIG3 = OFF, SIG4 = OFF, By obtaining SIG5 = ON and performing this control on the tube interlocking output I / F 23, a signal output required for the tube interlocking input I / F16 of the type B radiation generator is performed.
[0024]
【The invention's effect】
As described above, the generators having the same hardware configuration of the tube interlocking I / F can be connected and controlled only by changing the control table. Even when the hardware configuration of the tube interlocking I / F is different, the hardware specifications and protocol of the bus between the interlocking condition setting means 21 and the tube interlocking output I / F 23 are defined, and the input specifications are This can be handled by replacing the bus specification and the output specification with those adapted to the tube interlocking input I / F 16 of the radiation generating apparatus, and the interlocking condition setting means 21 and the interlocking condition input means 20 are positioned higher. Since the hardware and software (not shown) need not be changed, it is possible to easily connect to various types of radiation generators and control the irradiation field stop.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a radiation imaging apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of a general tube interlocking input / output I / F. FIG. 3 is a control table used for interlocking condition setting means. [Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Radiation tube 11 Irradiation field stop 12 Tube moving means 13 Aperture drive means 14 Tube interlock control means 15 Radiation control means 16 Tube interlock input I / F
17 Subject 18 Imaging means 19 Position detection means 20 Interlocking condition input means 21 Interlocking condition setting means 22 Control table 23 Tube interlocking output I / F

Claims (1)

An imaging region whose imaging region can be changed, and which obtains a radiation image by converting the intensity of radiation into an electrical signal by a radiation imaging device composed of a plurality of photoelectric conversion elements;
A control table that records a plurality of imaging areas of the imaging means and the distance between the center of each imaging area and the center of the maximum imaging area in the image receiving unit of the imaging means as the radiation field center, and input from the input means A signal for controlling the diaphragm according to the receiving form of the tube interlocking input I / F with reference to the control table by using the actual size of the image receiving unit of the imaging means and the actual size of the center of the irradiation field as an index, and the position of the radiation tube Interlocking condition setting means for changing to a control signal and outputting,
Based on the signal output from the interlocking condition setting means, a diaphragm driving means for driving an irradiation field stop for restricting an irradiation range of radiation emitted from the radiation tube, and a tube moving means for changing the position of the radiation tube emitting radiation. Tube interlocking control means for irradiating radiation to the imaging region and the corresponding irradiation center by controlling
A radiation imaging apparatus comprising:

Images