EP0624052B1 - X-ray generating system - Google Patents

X-ray generating system Download PDF

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Publication number
EP0624052B1
EP0624052B1 EP19940303246 EP94303246A EP0624052B1 EP 0624052 B1 EP0624052 B1 EP 0624052B1 EP 19940303246 EP19940303246 EP 19940303246 EP 94303246 A EP94303246 A EP 94303246A EP 0624052 B1 EP0624052 B1 EP 0624052B1
Authority
EP
European Patent Office
Prior art keywords
irradiation
time
cooling
ray
tube
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19940303246
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0624052A1 (en
Inventor
Sumiko C/O Intellectual Property Div. Kominato
Hiroshi C/O Intellectual Property Div. Mizuguchi
Masashi C/O Intellectual Property Div. Motoyama
Masami C/O Intellectual Property Div. Tomizawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toshiba Corp
Original Assignee
Toshiba Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toshiba Corp filed Critical Toshiba Corp
Publication of EP0624052A1 publication Critical patent/EP0624052A1/en
Application granted granted Critical
Publication of EP0624052B1 publication Critical patent/EP0624052B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/26—Measuring, controlling or protecting
    • H05G1/30—Controlling
    • H05G1/36—Temperature of anode; Brightness of image power
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/26—Measuring, controlling or protecting
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/26—Measuring, controlling or protecting
    • H05G1/54—Protecting or lifetime prediction

Definitions

  • This invention relates to an X-ray generating system, e.g. a portable type X-ray generating system which causes intermittent generation of X-rays for cooling the X-ray tube.
  • a desired tube voltage (the voltage between the anode and the cathode of an X-ray tube 105) set value 121 set by a tube voltage setting unit 101 as tube voltage setting means is outputted to a tube voltage control unit 102.
  • Tube voltage control unit 102 controls the value of a primary voltage, which is generated by a primary voltage generating unit 103, from the difference between tube voltage set value 121 and a tube voltage feed-back value 122.
  • the primary voltage generated by primary voltage generating unit 103 is converted to the tube voltage required by X-ray tube 105 by a booster 104. Thus it is designed so that the desired tube voltage is applied to X-ray tube 105. At the same time, the primary voltage is converted to tube voltage feed-back value 122 through a primary voltage divider 106, and then it is outputted to tube voltage control unit 102. Apart from this operation, when X-ray irradiation demand 123 is outputted from X-ray ON setting unit 111, an irradiation time monitor 113 starts a down-count from the irradiation time set by an irradiation time setting unit 112 as irradiation time setting means.
  • X-ray irradiation continues until an X-ray irradiation stop demand 125 is outputted by an X-ray OFF instruction unit 114 or until X-ray irradiation is stopped by a "Time Up" signal 124 from irradiation time monitor 113.
  • the prior art portable type X-ray generating system described above had the following problems.
  • the operator was required to perform control of the duty cycle (percentage of X-ray irradiation time and cooling time). Consequently: (a) the operator used to memorize the time of starting X-ray irradiation, and when that X-ray irradiation was completed the operator did not carry out the next X-ray irradiation until a time which matched the previous irradiation time had elapsed. (b) Even if tube voltages differed, the operator carried out cooling with a constant duty cycle.
  • GB-A-1 498 824 discloses an x-ray generating system comprising an apparatus for monitoring and estimating the loading of an X-ray tube.
  • This system comprises an irradiation control means for causing the X-ray tube to suspend irradiation as long as the sum of the temperature increase to be expected and the instantaneous actual or simulated temperature of the anode would exceed the maximum working temperature.
  • one object of this invention is to provide an X-ray generating system which does not cause heat damage to the X-ray tube.
  • Another object of this invention is to provide an X-ray generating system which is capable of efficient system management.
  • Still another object of this invention is to provide an X-ray generating system which is capable of reducing the operator's responsibility.
  • an X-ray generating system including an X-ray tube for generating X-rays and a tube voltage setting unit for setting a tube voltage applied to the X-ray tube.
  • the system further includes an irradiation time setting unit for setting an irradiation time of the X-rays by the X-ray tube, a high voltage generating unit for supplying the tube voltage to the X-ray tube to cause the X-ray tube to generate the X-rays based on the tube voltage, and an irradiation control unit connected to the tube voltage setting unit and the irradiation time setting unit.
  • the irradiation control unit compares the irradiation time with a maximum irradiation time determined by the tube voltage, divides the irradiation time into a plurality of divided irradiation times each being equal to or smaller than the maximum irradiation time when the irradiation time is larger than the maximum irradiation time, calculates a plurality of cooling times for the X-ray tube between the divided irradiation times and after a final one of the divided irradiation times when the irradiation time is larger than the maximum irradiation time, and controls the high voltage generating unit to cause the X-ray tube to generate the X-rays for one of the plurality of divided irradiation times, respectively, and to cause the X-ray tube to suspend irradiation of the X-rays for one of the plurality of cooling times, respectively.
  • Figure 1 is a block diagram showing an X-ray generating system according to an embodiment of this invention. In this embodiment, the following are provided in addition to the composition in Figure 10:
  • irradiation control unit 1 The functions of irradiation control unit 1 are achieved by a microprocessor. Irradiation time monitor 113 which is provided in the prior art X-ray generating system is incorporated in irradiation control unit 1.
  • the operator sets the desired tube voltage on tube voltage setting unit 101, and sets the desired irradiation time on irradiation time setting unit 112.
  • the X-ray ON instruction is performed on X-ray ON setting unit 111.
  • the X-ray generating system executes X-ray irradiation for the X-ray irradiation time as a whole which has been set. Whether the X-ray irradiation is executed by the divided irradiation or by the continuous radiation is judged by the X-ray generating system itself. If the X-ray OFF instruction is executed by X-ray OFF setting unit 114 during X-ray irradiation, the X-ray ON instruction is suspended.
  • Irradiation control unit 1 processes an irradiation and cooling schedule to the following rules, and executes it. (1) One irradiation time must not exceed the maximum irradiation time determined by the tube voltage. The maximum irradiation time is stored in derating memory 2. (2) When the set irradiation time exceeds the maximum irradiation time, divide the set irradiation time into each maximum irradiation time, and insert the cooling between each of these.
  • irradiation control unit 1 controls to commence X-ray irradiation and, at the same time, commences a down-count of irradiation time Te. This result of the down-count is displayed on irradiation time display 3.
  • irradiation control unit 1 commences a down-count of cooling time Tc, and the cooling remainder time (the result of down-count) is displayed on irradiation time display 3.
  • a "Cooling" display is executed on cooling mode display 4. But no display is executed on cooling mode display 5 because the X-ray irradiation is completed.
  • Irradiation control unit 1 finds cooling time Tc i by the following equations from the set total irradiation time Te and the derating data for the tube voltage value stored in derating memory 2.
  • Irradiation time Te 1 One maximum irradiation time max-Te
  • Cooling time Tc 1 (y/x) x
  • irradiation control unit 1 controls to commence X-ray irradiation and, at the same time, commences the down-count of total irradiation time Te and displays the result of the down-count on irradiation time display 3.
  • irradiation control unit 1 automatically switches OFF X-ray irradiation. Then, it displays the cooling remainder time on irradiation time display 3.
  • cooling mode display 4 displays "Cooling" on cooling mode display 4 and executes a warning display on cooling mode display 5 in order to warn that it will automatically commence X-ray irradiation after completion of the cooling time.
  • irradiation control unit 1 again executes X-ray irradiation ON. In the same way, it repeats the same operations n-1 times. In n-th time, X-ray irradiation is executed for irradiation time Te n , and then cooling is executed for cooling time Tc n .
  • FIG. 4A shows a flow chart illustrating the operation of irradiation control unit 1 in detail.
  • Cooling time Tc 2 Previous cooling remainder time Tc 12 + ((y/x) x Irradiation time Te 2 )
  • irradiation control unit 1 controls the scheduled irradiation and cooling by the operations for the previously described case when the irradiation remainder time is less than one maximum irradiation time ( Figure 2) or the case when the irradiation remainder time exceeds one maximum irradiation time ( Figure 3).
  • Figure 4 shows the case when the second irradiation time, which is the irradiation remainder time, does not exceed one maximum irradiation available time, so the X-ray irradiation warning display is not executed on cooling mode display 5.
  • irradiation control unit 1 When the power source is switched OFF during cooling, irradiation control unit 1 stores time T off when the power source was switched OFF and the cooling remainder time Tc 1 at that time in a memory which is not shown in Figure 1. Then, when the power source is switched ON again, irradiation control unit 1 reads T on from that clock and finds whether or not cooling is required and the required cooling time Tc 2 by the following equation.
  • ⁇ is a derating parameter and is the value equal to or smaller than 1.
  • Figure 5 shows the case where a is equal to 1.
  • cooling control unit 1 displays the cooling remainder time Tc 2 on irradiation time display 3 and, at the same time, displays "Cooling" on cooling mode dispay 4.
  • the power source is switched OFF during cooling after the previous X-ray irradiation is completed, so the X-ray irradiation warning is not executed on cooling mode display 5.
  • irradiation control unit 1 automatically executes X-ray irradiation ON.
  • This invention is not limited to this embodiment. Control of the system may be executed manually. For example, when the cooling is completed, at time T M , irradiation control unit 1 displays "X-ray ON input waiting" on a display (not shown). When finding this display, the operator inputs "X-ray ON demand" to the system. Based on this input, irradiation control unit 1 starts to execute X-ray irradiation for time Te 2 , and cooling for time Tc 2 . In the same way, the system and the operator repeat the same operation.
  • irradiation control unit 1 controls the system using the derating data stored in derating memory 2. This invention is not limited to this embodiment. In another embodiment, derating memory 2 may be omitted, and irradiation control unit 1 calculates every cooling time based on the tube voltage and the present irradiation time and executes next cooling for the calculated cooling time.
  • the design is to judge the suspension time with a built-in clock and automatically to select the sequence for the detected suspension time. Warming-up is stored as repeated sequences of irradiation, starting from a low tube voltage and rising to a high tube voltage by the rules described above, and cooling, which are all automatically executed.
  • a first X-ray irradiation is executed at a first tube voltage of 150 KV for a first irradiation time and then a first cooling is executed for a first cooling time determined by the first tube voltage and the first irradiation time.
  • a second X-ray irradiation is executed at a second tube voltage of 200 KV higher than the first tube voltage for a second irradiation time shorter than the first irradiation time, and then a second cooling is executed for a second cooling time longer than the first cooling time which is determined by the second tube voltage and the second irradiation time.
  • X-ray irradiations and coolings are executed alternately, with raising the tube voltages from 250 KV to 300 KV.
  • a final X-ray irradiation is executed at a final tube voltage of 300 KV for a final irradiation time again, and then cooling is executed for a final cooling time determined by the final tube voltage and the final irradiation time.
  • the final cooling is finished, the warming-up is completed.
  • This embodiment is provided with two cooling mode displays. However, these may be made one, and the case of stopping irradiation after completion of cooling and the case of continuous X-ray irradiation can be distinguished, for example, by changing the display mode.
  • FIG. 7 another embodiment of this invention is shown in Figures 7 to 9.
  • a temperature detection unit 6 is provided as the temperature detection means which can detect the temperature of X-ray tube 105.
  • derating memory 2 shown in Figure 1 is not necessary, so that it is omitted in Figure 7.
  • irradiation control unit 1 judges whether the temperature detected by temperature detection unit 6 is within the irradiation available range or not. If it is in the available range, that is, the detected temperature is below a temperature t 2 , irradiation control unit 1 starts X-ray irradiation and, at the same time, starts the irradiation time down-count by its built-in timer. Also, it executes a display for the irradiation remainder time on irradiation time display 3.
  • Irradiation control unit 1 always monitors the temperature of X-ray tube 105 by temperature detection unit 6. If the temperature is outside the irradiation available range, that is, the detected temperature is over a temperature t 1 , it automatically switches OFF X-ray irradiation. It then starts to execute cooling and displays "Cooling" on cooling mode display 4. Also, when executing further X-ray irradiation after the completion of cooling, it executes an irradiation warning display on cooling mode display 5. At the same time, irradiation control unit 1 monitors the temperature from temperature detection unit 6 and continues to execute cooling until the temperature once more reaches the irradiation available temperature (until the irradiation available re-set temperature t 2 is reached).
  • irradiation control unit 1 automatically starts X-ray irradiation. It then repeats the same operations. This is continued until "Time Up” is reached, or until X-ray OFF demand 125 is received.
  • irradiation control unit 1 only displays "Cooling" on cooling mode display 4.
  • hysteresis is provided at the irradiation available temperature. This is because, when the temperature rises to X-ray irradiation available upper limit value t 1 , the system enters the cooling mode. Then, the temperature begins to fall from that upper limit value t 1 . However, if X-ray irradiation is commenced immediately on the basis that the temperature is below that upper limit value t 1 , the temperature will rapidly reach that upper limit value t 1 again and the system will enter the cooling mode again. If this happens, the X-ray irradiation time will become very short and damage to X-ray tube 105 will occur. It is for this reason that hysteresis is provided in the irradiation available temperature.
  • the case in Figure 9 is an example of a case when a repeat X-ray ON command is received during cooling "A" when no X-ray irradiation was scheduled after cooling.
  • X-ray ON command 123 is received during cooling "A"
  • X-ray irradiation will become immediately available.
  • X-ray irradiation and cooling will be repeated by the same operation as in the case of Figure 8.
  • simple switching to an algorithm can also be performed that X-ray irradiation is not available if irradiation available re-set temperature t 2 has not been reached.
  • irradiation control unit 1 automatically executes X-ray irradiation ON.
  • This invention is not limited to this embodiment. Control of the system of this case may also executed manually as described before, the same as in the operation shown in Figure 3.
  • cooling is carried out for a cooling time calculated based on that X-ray irradiation time and the set tube voltage value.
  • X-ray irradiation is performed by calculating the irradiation permitted time so that it does not exceed one maximum irradiation available time based on the cooling elapsed time at the time of reception of that instruction and the set tube voltage value.
  • cooling is performed by calculating the cooling time from the remaining cooling time at the time of reception of the instruction, that permitted X-ray irradiation time and the set tube voltage value.
  • X-ray irradiation when X-ray irradiation is re-performed after a long period has elapsed since the time of completion of the previous X-ray irradiation, warming-up is required. More than one series of plans for the tube voltage values and the irradiation times corresponding to this kind of warming-up are stored in the irradiation control unit. X-ray irradiation is controlled by selecting one of these plans based on the time elapsed from the time of completion of the previous X-ray irradiation.
  • X-ray irradiation and cooling can also be controlled by monitoring the temperature of the X-ray tube. In this way also, efficient system operation is possible without resulting in heat damage to the X-ray tube by monitoring the temperature of the X-ray tube.

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  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • X-Ray Techniques (AREA)
EP19940303246 1993-05-07 1994-05-05 X-ray generating system Expired - Lifetime EP0624052B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP10668893A JPH06318500A (ja) 1993-05-07 1993-05-07 Ｘ線発生装置
JP10668893 1993-05-07
JP106688/93 1993-05-07

Publications (2)

Publication Number Publication Date
EP0624052A1 EP0624052A1 (en) 1994-11-09
EP0624052B1 true EP0624052B1 (en) 1999-07-14

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ID=14439995

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19940303246 Expired - Lifetime EP0624052B1 (en) 1993-05-07 1994-05-05 X-ray generating system

Country Status (4)

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EP (1) EP0624052B1 (ja)
JP (1) JPH06318500A (ja)
DE (1) DE69419454T2 (ja)
DK (1) DK0624052T3 (ja)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2003086028A1 (ja) * 2002-04-05 2005-08-18 浜松ホトニクス株式会社 Ｘ線管制御装置及びｘ線管制御方法
DE10332417A1 (de) * 2003-07-16 2005-02-24 Sirona Dental Systems Gmbh Verfahren zur Steuerung eines Röntgengeräts und Röntgengerät
JP4494355B2 (ja) * 2006-03-07 2010-06-30 富士フイルム株式会社 放射線画像撮影装置及び放射線画像撮影装置の制御方法
JP5063391B2 (ja) * 2008-01-31 2012-10-31 キヤノン株式会社 放射線画像撮影装置及びその駆動方法
JP2009266688A (ja) * 2008-04-25 2009-11-12 Shimadzu Corp Ｘ線測定システム
US11147528B2 (en) * 2019-08-16 2021-10-19 GE Precision Healthcare LLC Methods and systems for X-ray tube conditioning
CN113056077B (zh) * 2019-12-27 2024-02-09 韩国威泰有限公司 X射线发生器
DE102020209632A1 (de) 2020-07-30 2021-07-29 Siemens Healthcare Gmbh Temperaturgesteuerte Röntgeneinrichtung
DE102020210804A1 (de) 2020-08-26 2021-09-02 Siemens Healthcare Gmbh Steuern einer Röntgeneinrichtung gemäß einer thermischen Belastung

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2345947C3 (de) * 1973-09-12 1981-12-03 Philips Patentverwaltung Gmbh, 2000 Hamburg Schaltungsanordnung zur Überwachung der Belastung einer Röntgenröhre
US3961173A (en) * 1974-11-20 1976-06-01 Varian Associates Heat unit integrator for X-ray tubes
US4386320A (en) * 1978-09-15 1983-05-31 Lafrance Robert R X-Ray system signal derivation circuits for heat unit indicators and/or calibration meters
DE2927207A1 (de) * 1979-07-05 1981-01-08 Philips Patentverwaltung Verfahren zum steuern der einer drehanoden-roentgenroehre zugefuehrten elektrischen leistung
JPS5630297A (en) * 1979-08-20 1981-03-26 Toshiba Corp Overload preventive device for x-ray tube
JPS6269495A (ja) * 1985-09-20 1987-03-30 Toshiba Corp 回転陽極ｘ線管駆動装置

Also Published As

Publication number Publication date
DK0624052T3 (da) 2000-01-24
DE69419454D1 (de) 1999-08-19
EP0624052A1 (en) 1994-11-09
JPH06318500A (ja) 1994-11-15
DE69419454T2 (de) 2000-06-15

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