JP2006120548A - X-ray tube arrangement and heating control method of x-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent variation in a captured image due to an excessive increase in filament temperature and an X-ray tube current exceeding a set value even when an image capturing button is pressed for a shorter time than usual. An X-ray tube heating control method is provided.
Detection means for detecting the preheating period in an X-ray tube control apparatus that performs main heating after heating an X-ray tube filament by performing preflash at an imaging start timing after preheating. And control means for changing the pre-flash condition for the X-ray tube filament according to the detection result of the detecting means.
[Selection] Figure 1

Description

  The present invention relates to an X-ray tube apparatus and an X-ray tube heating control method equipped in an X-ray diagnostic apparatus or the like.

  In the X-ray tube apparatus, an X-ray is generated by causing a current to flow through the cathode filament and heating it, and causing the emitted thermoelectrons to collide with the anode target with a high voltage. The tube current flowing by the electron beam from the cathode to the anode is generally controlled by increasing or decreasing the current flowing to the cathode filament. Increasing or decreasing the filament current changes the filament temperature and changes the amount of thermoelectrons emitted from the filament. Accordingly, the tube current also changes (for example, Patent Document 1).

  In order to increase or decrease the filament temperature of the X-ray tube, the filament current is increased or decreased. However, since the filament has thermal inertia, there is a certain delay (about 1 second) for the temperature to follow the fluctuation of the filament current. Arise. When the photographing button is pressed, the supply of filament current is started together with the application of the tube voltage. Due to the thermal inertia, the actual tube current does not reach the set value during a period of about 1 second until the filament temperature is stabilized at the set temperature.

  As described above, the actual tube current does not reach the set value during the period of about 1 second from when the photographing button is pressed until the filament temperature reaches the set temperature. As a result, the fluoroscopic image during this period is insufficient in density and cannot be optimal for the surgeon performing the diagnosis.

  Also, when automatic brightness correction is performed during fluoroscopy, that is, when the tube current is dynamically changed during fluoroscopy so as to stabilize the brightness level, there is a delay until the tube current actually changes to the set value. In other words, when the subject thickness changes abruptly, a certain amount of time is required until the brightness of the fluoroscopic image is stabilized.

  As a method for solving such a shortage of tube current, there is a preflash that heats a filament of an X-ray tube apparatus. This is a technique for raising the filament temperature of the X-ray tube in a short time, and the time from pressing the “shooting button” on the X-ray tube device to the actual X-ray irradiation can be shortened. The desired image can be obtained with good timing.

  Here, if the X-ray tube filament is always heated for imaging so that the “imaging button” can be pressed at any time, the preflash is not necessary. However, since the life of the filament of the X-ray tube is shortened in inverse proportion to the heating time if it is always heated, such a method cannot be adopted, and preflash has been used after all.

Japanese Patent Publication No. 60-19639

The preflash is obtained by multiplying the filament heating amount H ₀ determined by the imaging conditions (X-ray tube voltage, X-ray tube current) set on the operation panel of the X-ray high voltage apparatus by a predetermined constant A (what A method of taking a predetermined time T is adopted. The main heating amount H ₀ is determined by the imaging conditions (X-ray tube voltage, X-ray tube current) set on the operation panel of the X-ray high voltage apparatus.

  However, if the next shot was taken before the filament temperature had dropped sufficiently since the previous shot was completed, i.e. if the shooting interval was short, the preflash would be As a result, the X-ray tube current exceeded the set value, resulting in variations in the captured images.

  The present invention has been made in view of the above problems, and its purpose is to set the X-ray tube current without increasing the filament temperature even when the photographing button is pressed for a shorter time than usual. An object of the present invention is to provide an X-ray tube apparatus and a method for controlling the heating of an X-ray tube which prevent variations in captured images due to exceeding the value.

  An X-ray tube apparatus according to the invention described in claim 1 for solving the above-mentioned problem is the X-ray tube after heating the X-ray tube filament by performing preflash at the imaging start timing after the preheating. In the X-ray tube apparatus that performs the main heating of the filament, the X-ray tube filament is controlled by changing the preflash condition according to the detection means for detecting the preheating period and the detection result of the detection means And a control means for providing the control means.

  The X-ray tube apparatus according to the second aspect of the present invention for solving the above-described problem is the X-ray tube apparatus according to the first aspect, wherein the control means detects the previous preliminary heating result by the detection means. When the time is shorter than this time, the pre-flash condition is set so that the amount of electric power for controlling the X-ray tube filament is smaller than the previous time.

  The X-ray tube apparatus according to the invention described in claim 3 for solving the above-mentioned problem is the X-ray tube apparatus according to claim 1, wherein the control means includes the preheating period and the preflash condition. And the X-ray tube filament is controlled by referring to the table based on the detection result by the detection means and changing to the pre-flash condition corresponding to the detection result. And

  An X-ray tube apparatus according to a fourth aspect of the present invention for solving the above-mentioned problems is the X-ray tube apparatus according to any one of the first to third aspects, wherein the pre-flash condition is set at the time of the pre-flash. It is a combination of any one or more of the voltage, current, power of the filament and the time for performing the preflash.

  The X-ray tube apparatus according to the invention described in claim 5 for solving the above-described problem is the X-ray tube apparatus according to any one of claims 1 to 4, wherein the detection means sets the preheating period. It is a timer for measuring time.

  The X-ray tube apparatus according to claim 6 for solving the above-mentioned problem is the X-ray tube apparatus according to claim 5, wherein the timer uses the interval of the imaging start timing to perform the preliminary heating. It is characterized in that the period of time is measured.

  The X-ray tube heating control method according to the invention described in claim 7 for solving the above-mentioned problems is a preheating process for preheating the X-ray tube filament, and the preheating process upon receiving an imaging start signal. And a pre-flash process for heating the X-ray tube filament, and a main heating process for heating the X-ray tube filament for a predetermined time after the pre-flash process is completed. An X-ray tube heating control method for performing a preheating process, wherein the preflash process detects a time required for the previous preheating process after the previous preheating process is completed, and detects the detected time The X-ray filament is controlled to be heated by controlling pre-flash conditions corresponding to the above.

  An X-ray tube heating control method according to an eighth aspect of the invention for solving the above-mentioned problem is the X-ray tube heating control method according to the seventh aspect, wherein the time required for the preliminary heating step is the previous time. When the preheating time is shorter, the preflash condition is set so that the amount of power for controlling the X-ray tube filament is less than the previous time.

  In order to solve the above problem, the X-ray tube heating control method according to the invention described in claim 9 is the X-ray tube heating control method according to claim 7 or 8, wherein the preflash condition is the It is controllable by any one or a combination of the current, voltage, power and time for performing the preflash in the preflash process.

  According to the present invention, the filament power (current / voltage) at the time of preflash or the time required for it is controlled according to the preheating time (time from the previous photographing signal off to the photographing signal on). The temperature of the filament after preflash is not increased too much. This leads to that the temperature of the filament of the X-ray tube is always stable during the main heating, and as a result, a stable X-ray image can be obtained.

  Hereinafter, an X-ray tube apparatus according to the present invention will be described with reference to the drawings according to preferred embodiments. X-ray tube apparatuses are applied in various fields such as the medical field and the non-destructive inspection field. Here, the medical field will be described as an example. Furthermore, the X-ray tube apparatus is installed in various apparatuses such as an X-ray diagnostic apparatus and an X-ray CT in the medical field. An example of application to an X-ray diagnostic apparatus with many tube current control opportunities will be described.

  The X-ray diagnostic apparatus will be described briefly. In the X-ray diagnostic apparatus, the X-ray tube of the X-ray tube apparatus is a flat panel or an X-ray detector composed of a combination of an image intensifier and a TV camera. It is held by an arm or a stand with the subject interposed therebetween. Image data is generated and displayed based on the X-ray signal detected by the X-ray detector.

  In the present invention, as a technique for obtaining a stable X-ray image by eliminating variations in filament temperature during the main heating, the present inventor has found a technique for controlling the amount of pre-flash power according to the length of the preheating time. This is what I came up with. Therefore, hereinafter, the X-ray tube filament control current and the voltage applied to the X-ray tube filament are relative to the power in the X-ray tube apparatus according to the present invention.

  FIG. 1 is a diagram showing a configuration of a main part of the X-ray tube apparatus according to the present embodiment. As shown in FIG. 1, the X-ray tube device according to this embodiment includes a grid control X-ray tube 10, an X-ray high voltage device 20, and a control device 30. The X-ray tube 10 has a glass bulb 11 whose interior is maintained at a high vacuum. The glass bulb 11 generally contains a rotary anode 12 and a cathode. The cathode is composed of a filament 13 and a focusing electrode (not shown). A grid 14 is disposed between the cathode and the anode 11.

  The X-ray high voltage device 20 includes a high voltage power supply 21 for applying a high voltage between the anode 12 and the cathode, a high voltage control circuit 22 for controlling the output of the high voltage power supply 21, and filament control for the filament 13. A filament heating power source 23 that supplies current, a grid control power source 24 that applies a negative bias voltage (grid control voltage) to the grid 14 with respect to the cathode 13, and a filament heating power source 23 and a grid control power source 24 are controlled. And a cathode control circuit 25.

  The control device 30 has an X-ray control circuit 31. The X-ray control circuit 31 supplies a tube voltage control signal to the high voltage control circuit 22. A voltage corresponding to the tube voltage control signal is applied between the anode 12 and the cathode. The X-ray control circuit 31 supplies a filament current control signal and a grid voltage control signal to the cathode control circuit 25. A filament control current corresponding to the filament current control signal is generated from the filament heating power source 23. When the tube current is not flowing (during preheating), the current that actually flows through the filament 13 matches the filament control current, and when the tube current is flowing, the current is the sum or difference between the filament control current and the tube current. Match. The grid control power supply 24 reduces the grid voltage from the cathode potential by a voltage corresponding to the grid voltage control signal. The emission of electrons can be controlled by adjusting the grid potential with respect to the cathode potential. The control device 30, particularly the X-ray control circuit 31, corresponds to the control means described in the claims.

  Connected to the X-ray control circuit 31 is a tube voltage setting unit, a tube current operation unit, and an operation unit 32 having an imaging button. The X-ray control circuit 31 performs tube voltage control according to the tube voltage (tube voltage setting value) set via the tube voltage setting unit and the tube current (tube current setting value) set via the tube current setting unit. A signal, a filament current control signal, and a grid control signal are generated when the photographing button is pressed.

  The X-ray control circuit 31 is provided with a reference storage unit 33. The reference storage unit 33 stores in advance a preflash condition corresponding to the preheating time, that is, the power of the filament 13 corresponding to the preheating time or the time for performing the preflash corresponding to the preheating time in the form of a table. Has been. This preflash condition may be a combination of any one of the current of the filament 13 corresponding to the preheating time, the voltage applied to the X-ray tube, the power depending on them, and the preflash time. In addition to the preflash conditions, the reference storage unit 33 stores preheating conditions and main heating conditions in advance. Here, preheating conditions are the electric energy of the filament 13 at the time of preheating, for example. The main heating condition is, for example, the amount of power of the filament 13 during the main heating. Here, the amount of electric power is proportional to the amount of heating, and can be controlled by any of the voltage, current, and electric power of the filament 13 or the preflash time during which they are applied.

An example of the table stored in advance in the reference storage unit 33 is shown in FIG. FIG. 8A shows a table (the power H of the filament 13 is constant) in which the preheating time is associated with the preflash time corresponding thereto, and FIG. 8B shows the preheating time. FIG. 6 shows a table (pre-flash time T is constant) that correlates the power ratio of the filament 13 corresponding thereto. According to the tables shown in FIGS. 8A and 8B, the preflash time (T ₂ ) to be set and the power ratio of the filament 13 (the power H ₂ of the filament 13 during preflash and the filament 13 during main heating). The ratio of the power H ₀ to the power H ₀ is set to be shorter or smaller as the preheating time is shorter.

  Then, the X-ray control circuit 31 refers to the table for the relationship between the preheating time set in the reference storage unit 33, the power of the filament 13 and the preflash time, and the filament current control signal and / or Change the grid control signal. The power of the filament 13 may be the filament control current or voltage.

  FIGS. 2 and 3 show an X-ray tube heating control method according to this embodiment, in which an X-ray control circuit 31 controls an X-ray control circuit 31 in response to pressing of an imaging button (on / off of an imaging signal) by an operator. It is a figure which shows the electric power of a tube, and the time which each requires preheating of the filament 13, a preflash process, and this heating process.

  As shown in FIGS. 2 and 3, in imaging using the X-ray tube apparatus in the present embodiment, the “preheating” process, the “preflash” process, and the “main heating” process are performed on the filament of the X-ray tube. Is performed as a series of operations. The shooting start timing in this claim refers to the timing when the shooting button is pressed by the operator (shooting signal on).

Specifically, when the photographing button of the operation unit 32 is input (the photographing signal is turned on), the filament 13 that has been in the preheating state can be smoothly brought into the main heating state at a temperature preset in the main heating condition. A pre-flash process for shifting is performed for a predetermined time T ₁ (t _{1 to} t ₂ ) in accordance with the pre-heating time immediately before that, and then photographing is performed based on the pre-flash conditions and the main heating conditions set in advance. The filament 13 is fully heated until it is finished (the imaging signal is turned off) (t _{2 to} t ₃ ).

The “preflash” process is a power larger than the power H ₀ per unit time of the filament 13 determined by the imaging conditions (voltage applied to the X-ray tube, filament current) set by the operation unit 32. This is a process in which H ₁ is given for a predetermined time (T ₁ ).

Hereinafter, the “preheating” process, the “preflash” process, and the “main heating” process in the present embodiment will be described with reference to FIG. 2 and FIG. First, before the radiographing button is pressed (˜t ₁ ), the current control of the filament 13 by the X-ray control circuit 31 is compared by the X-ray control circuit 31 that refers to the preheating condition recorded in the reference storage unit 33. Is set to a low preheating current. In this way, a preheating current flows through the filament 13 and the filament 13 is preliminarily heated.

Then, when the imaging button is pressed by the operator with the filament 13 preheated (t ₂ ), the fluoroscopic signal is shifted from the off level to the on level from the operation unit 32 to the X-ray control circuit 31. The state continues until the heating process ends (t ₄ ). The fluoroscopy is performed while the fluoroscopy signal is maintained at the on level.

At this time, the X-ray control circuit 31 refers to the main heating condition and the preflash condition stored in the reference storage unit 33, and the preflash period (t) in which a current (power) larger than the preheating current is set. and ₁ ~t _2), heating control filament 13 out and the heating period in a small current (power) than the current of the pre-flash period (power) _(t 2 ~t _3). Specifically, after the photographing button is pressed by the operator, the pre-flash period time corresponding to the preheating time until then is obtained from the table of the reference storage unit 33 (see FIG. 8A). The heating of the filament 13 is controlled. The pre-flash period is a period indicating the pre-flash process, and the main heating period is a period indicating the main heating process.

Then, when the time of the pre-flash period has elapsed (t ₂ ), the X-ray control circuit 31 follows the power and the main heating time acquired with reference to the main heating condition stored in the reference storage unit 33. The filament 13 is heated and controlled until the end of the main heating (t ₃ ).

Thereafter, as shown in FIGS. 2 and 3, the X-ray control circuit 31 refers to the preheating condition stored in the reference storage unit 33 until the second imaging instruction (t ₄ : imaging signal ON) is made. Thus, preheating is performed for a time T _off (t _{3 to} t ₄ ) with the amount of electric power based on the preheating conditions.

Here, the X-ray control circuit 31 is provided with a timer 31a for detecting an imaging signal input by the operator. The timer 31a is set by the operator from the end of the main heating process (t ₃ ). The elapsed time until the photographing button is pressed (t ₄ ), that is, the preliminary heating time is measured. This timer 31a is a detecting means referred to in this claim. The timer 31a detects the photographing start timing when the photographing button is pressed, and calculates the preheating time by subtracting the time required for the preflash process and the main heating process from the time elapsed during that time.

Therefore, as shown in FIG. 2, the X-ray control circuit 31 is based on the table (see FIG. 8A) stored in the reference storage unit 33 according to the preheating time (t _{3 to} t ₄ ). as a pre-flush condition specified in, performs predetermined time _T 2 _(t 4 ~t ₅₎ with respect to pre-heating time _{T off (t} 3 ~t ₄₎ pre-flash operation after the lapse of the filament 13.

After the pre-flash time (T ₂ ) thus specified has elapsed, the main heating process (t _{5 to} t ₆ ) with a current (power) smaller than the current (power) in the pre-flash process is performed. The filament 13 is preheated again by the X-ray control circuit 31 referring to the preheating conditions stored in the reference storage unit 33 (t _6- ).

On the other hand, as shown in FIG. 3, when the timer 31a is the measured preliminary heating time _{T off (t} 3 ~t _4), shorter than the preliminary heating time _{T off (t} 3 ~t ₄₎ shown in FIG. 2 The X-ray control circuit 31 determines the preflash time T specified based on the table (see FIG. 8A) set in the reference storage unit 33 according to the time (t _{3 to} t ₄ ). ₂ (t _{4 to} t ₅ ), a preflash process is performed on the filament 13 after the preheating time T _off (t _{3 to} t ₄ ) has elapsed. In this case, as is clear from FIGS. 2 and 3, the preheating period T _off proportionally if short pre flush time T ₂ also flops refresh time T _{1 (preheating} time if long enough pre (Flash time) is set shorter.

After the pre-flash time (T ₂ ) thus specified has elapsed, the main heating process (t _{5 to} t ₆ ) with a current (power) smaller than the current (power) in the pre-flash process is performed. The filament 13 is preheated again by the X-ray control circuit 31 referring to the preheating conditions stored in the reference storage unit 33 (t _6- ).

FIG. 5 is a diagram showing the filament temperature in each process (period) of the “preheating” process to the “preflash” process to the “main heating” process in one embodiment of the X-ray tube apparatus according to the present invention; FIG. 4 shows, as a comparative example of FIG. 5, filament temperature in each period when both “pre-flash” times (T ₁ ) are set to the same time out of the two shootings (shooting signal ON to shooting signal OFF). FIG. 4 and 5, the temperature of the filament 13 is indicated by a broken line.

As shown in FIG. 5 showing the present invention, the preflash time (T ₂ ) at the time of the second photographing is set to be longer than the preflash time (T ₁ ) at the time of the first photographing depending on the time required for the preheating. By setting the length short, the filament temperature does not become too high as shown in FIG. 4, and the filament 13 temperature is flat in the main heating process (t _{5 to} t ₆ ) at the second imaging. It can be confirmed by the transition.

  This indicates that the variation in the tube current of the X-ray tube for each imaging (irradiation) has been improved, and the interval (imaging signal ON to imaging signal OFF) for operating the imaging button of the operator is shortened. There is room, and the inspection itself can be performed in a short time.

  Therefore, according to the present invention, the pre-flash time is controlled in accordance with the preheating time (the time from the previous photographing signal off to the photographing signal on), so that the temperature of the filament 13 after the pre-flash process is controlled. Is no longer too high. This leads to the temperature of the filament 13 of the X-ray tube being always stable during the main heating process, and as a result, a stable X-ray image can be obtained.

(Other embodiments)
Next, another embodiment of the present invention will be described below with reference to the drawings. FIGS. 6 and 7 illustrate an X-ray tube heating control method according to this embodiment, in which an X-ray control circuit 31 controls an X-ray control circuit 31 in response to pressing of an imaging button (ON / OFF of an imaging signal) by an operator. It is a figure which shows the electric power of a tube, and the time which each requires in the preheating process of a filament, a preflash process, and this heating process.

  As shown in FIGS. 6 and 7, even in imaging using the X-ray tube apparatus in the present embodiment, the “preheating” process, the “preflash” process, and the “main heating” are performed on the filament 13 of the X-ray tube. The process is performed as a series of actions.

Specifically, when the photographing button of the operation unit 32 is input (the photographing signal is turned on), the pre-heated filament 13 that has been in the pre-heated state is preliminarily moved to the main heating state at a preset temperature. The flash process is performed for a predetermined time T ₁ (t _{1 to} t ₂ ) in accordance with the immediately preceding preheating time, and then the photographing is finished based on the preflash conditions and the main heating conditions set in advance (the photographing signal is turned off). Until this time (t _{2 to} t ₃ ), the filament 13 is heated.

Note that the “preflash” process is the power per unit time of the filament 13 determined by the imaging conditions (voltage applied to the X-ray tube, filament current) set by the operation unit 32 as in the above-described embodiment. This is a process in which a power H ₁ greater than H ₀ is given for a predetermined time (T ₁ ).

Hereinafter, the “preheating” process, the “preflash” process, and the “main heating” process in the present embodiment will be described with reference to FIGS. 6 and 7. First, before the radiographing button is pressed (˜t ₁ ), the current control of the filament 13 by the X-ray control circuit 31 is set to a relatively low preheating current by the X-ray control circuit 31 referring to the reference storage unit 33. Is done. In this way, a preheating current flows through the filament 13 and the filament 13 is preliminarily heated.

When the imaging button is pressed by the operator with the filament 13 preheated (t ₂ ), the fluoroscopic signal is shifted from the off-level to the on-level from the operation unit 32 to the X-ray control circuit 31, and imaging is performed. The state continues until the button is pressed again (t ₄ ). The fluoroscopy is performed while the fluoroscopy signal is maintained at the on level.

At this time, the X-ray control circuit 31 refers to the reference storage unit 33, the preflash period (t _{1 to} t ₂ ) in which a current (power) larger than the preheating current is set, and the preflash period The filament 13 is heated and controlled during the main heating period (t _{2 to} t ₃ ) with a current (power) smaller than the current (power). Specifically, after the photographing button is pressed by the operator, the pre-flash period time corresponding to the preheating time until then is obtained from the table of the reference storage unit 33 (see FIG. 8A). The heating of the filament 13 is controlled.

Then, when the time of the pre-flash period has elapsed (t ₂ ), the X-ray control circuit 31 follows the power and the main heating time acquired with reference to the main heating condition stored in the reference storage unit 33. The filament 13 is heated and controlled until the end of the main heating (t ₃ ).

Thereafter, as shown in FIGS. 6 and 7, the X-ray control circuit 31 refers to the preheating conditions stored in the reference storage unit 33 until the second imaging instruction (t ₄ : imaging signal ON) is made. Thus, preheating is performed at the time T _off (t _{3 to} t ₄ ) with the same power as the previous time.

Here, also in the present embodiment, the X-ray control circuit 31 is provided with a timer 31a for detecting an imaging signal input by the operator, and the timer 31a is at the end of the main heating process (t _3). ) To the time (t ₄ ) when the photographing button is pressed by the operator, that is, the preheating time is measured.

Therefore, as shown in FIG. 6, the X-ray control circuit 31 uses the power of the table (see FIG. 8B) set in the reference storage unit 33 according to the preheating time (t _{3 to} t ₄ ). Elapse of preheating time T _off (t _{3 to} t ₄ ) in order to give power H ₂ specified based on the ratio (H ₂ / H ₀ ) of H ₂ (H ₀ is preset by the present heating condition) The subsequent pre-flash process (t _{4 to} t ₅ ) is performed with a filament current corresponding to the power H ₂ or a voltage applied to the X-ray tube.

Thus, after the pre-flash process (t _{4 to} t ₅ ) has elapsed, the main heating process (t _{5 to} t ₆ ) with a current (power) smaller than the current (power) in the pre-flash process is performed. Then, the filament 13 is preheated again by the X-ray control circuit 31 that refers to the preheating conditions stored in the reference storage unit 33 (t _6- ).

On the other hand, as shown in FIG. 7, when the timer 31a is the measured preliminary heating time _{T off (t} 3 ~t _4), shorter than the preliminary heating time _{T off (t} 3 ~t ₄₎ shown in FIG. 6 The X-ray control circuit 31 compares the power ratio (H ₂ / H ₀ ) of the table (see FIG. 8B) set in the reference storage unit 33 according to the time (t _{3 to} t ₄ ). ) power _H 2 _{(H 0} specified based on the order gives a preset power) by the heating conditions, pre-heating time _{T off (t} 3 ~t ₄₎ pre-flush step after lapse _(t 4 ~ t ₅ ) is performed with a filament current corresponding to the power or a voltage applied to the X-ray tube. Here, as it is clear from FIGS. 6 and 7, when the preheating time T _off is short, less than proportionately power H ₂ also power H _{1 (power} when the preheating time is sufficiently long) Is set.

In this way, after the preflash time T ₂ (t _{4 to} t ₅ ) has elapsed, the main heating process (t _{5 to} t ₆ ) with a current (power) smaller than the current (power) in the preflash process. ), The filament 13 is preheated again by the X-ray control circuit 31 referring to the preheating conditions stored in the reference storage unit 33 (t _6- ).

  As described above, according to the present invention, the power (filament current, tube voltage) in the preflash process is controlled according to the preheating time (the time from the previous photographing signal off to the photographing signal on). Therefore, the temperature of the filament 13 after the preflash process is not excessively increased. This leads to the temperature of the filament 13 of the X-ray tube being always stable during the main heating process, and as a result, a stable X-ray image can be obtained.

  The above-described embodiment is an example of the present invention, and the present invention is not limited to the above-described embodiment. In the implementation stage, various modifications can be made without departing from the scope of the invention. Furthermore, the above embodiment includes various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, some constituent requirements may be deleted from all the constituent requirements shown in the embodiment.

The block diagram which shows the structure of one Embodiment of the X tube apparatus which concerns on this invention. Shows a preheating time (T _off) is controlled by the X-ray control circuit on the basis of the pre-flash time (T ₂₎ in one embodiment of a heating control method of the X-ray tube device and the X-ray tube according to the present invention . Shows a preheating time (T _off) is controlled by the X-ray control circuit on the basis of the pre-flash time (T ₂₎ in one embodiment of the heating method of controlling the X-ray tube device and the X-ray tube according to the present invention . The figure which shows the temperature change of the filament controlled by the X-ray control circuit based on preheating time ( _Toff ) in one Embodiment of the X-ray tube apparatus which concerns on this invention, and the heating control method of an X-ray tube. The figure which shows the temperature change of the filament controlled by the X-ray control circuit based on preheating time ( _Toff ) in one Embodiment of the X-ray tube apparatus which concerns on this invention, and the heating control method of an X-ray tube. FIG. 4 shows the pre-flash power (H ₂ ) controlled by the X-ray control circuit based on the preheating time (T _off ) in another embodiment of the X-ray tube apparatus and X-ray tube heating control method according to the present invention. Figure. FIG. 4 shows the pre-flash power (H ₂ ) controlled by the X-ray control circuit based on the preheating time (T _off ) in another embodiment of the X-ray tube apparatus and X-ray tube heating control method according to the present invention. Figure. Associating the preheating time (T _off ) and the preflash time (T ₂ ) or the power ratio (H ₂ / H ₀ ) of the X tube apparatus and the X-ray tube heating control method according to the present invention. The figure which shows a table.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Grid control X-ray tube 11 Glass valve 12 Anode 13 Filament 14 Grid 20 X-ray high voltage apparatus 21 High voltage power supply 22 High voltage control circuit 23 Filament heating power supply 24 Grid control power supply 25 Cathode control circuit 30 Control apparatus 31 X-ray control Circuit 32 Operation unit 33 Reference storage unit

Claims (9)

In the X-ray tube apparatus that performs the main heating of the X-ray tube filament after heating the X-ray tube filament by performing preflash at the imaging start timing after the preheating,
Detecting means for detecting the preheating period;
An X-ray tube apparatus comprising: a control unit that controls the X-ray tube filament by changing the pre-flash condition according to a detection result of the detection unit.   The control means sets the preflash condition so that the amount of electric power for controlling the X-ray tube filament is smaller than the previous time when the detection result by the detection means is shorter than the previous preheating time. The X-ray tube apparatus according to claim 1.   The control means includes a table in which the preheating period and the preflash conditions are associated with each other, and the preflash of the preflash corresponding to the detection result is referred to the table based on the detection result of the detection means. The X-ray tube apparatus according to claim 1, wherein the X-ray tube filament is controlled by changing to a condition.   The condition of the preflash is any one or a combination of the filament voltage, current, power, and the preflash time during the preflash. An X-ray tube apparatus according to the above.   The X-ray tube apparatus according to claim 1, wherein the detection unit is a timer that measures a period of the preliminary heating.   The X-ray tube apparatus according to claim 5, wherein the timer measures the preheating period using the interval of the imaging start timing. A preheating process for preheating the X-ray tube filament;
Receiving a radiographing start signal, ending the preliminary heating process, and heating the X-ray tube filament;
A heating control method of the X-ray tube, wherein the X-ray tube filament is heated for a predetermined time after the pre-flash process, and the preliminary heating process is performed again after the heating process.
The pre-flash process detects the time required for the previous pre-heating process after finishing the previous pre-heating process, and controls the pre-flash condition corresponding to the detected time, thereby the X-ray filament. A method for controlling the heating of an X-ray tube, wherein the heating is controlled.   When the time required for the preheating process is shorter than the previous preheating time, the preflash condition is set so that the amount of electric power for controlling the X-ray tube filament is smaller than the previous time. The X-ray tube heating control method according to claim 7. The pre-flash condition can be controlled by any one or a combination of the current, voltage, power and time of the pre-flash in the X-ray filament during the pre-flash process. The heating control method for an X-ray tube according to 7 or 8.

Images