Diagonostic service system for CT scanners

• US 4,853,946 A
• Filed: 06/02/1988
• Issued: 08/01/1989
• Est. Priority Date: 11/14/1986
• Status: Expired due to Term

• Current Assignee: Picker International, Inc. (Marconi Holdings Company Limited)
• Original Assignee: Picker International, Inc. (Marconi Holdings Company Limited)
• Inventors: Resnick, Theodore A., Dupuis, Walter A., Elliott, Richard J.
• Primary Examiner(s): Church, Craig E.
• Application Number:
  US07/201,405
• Time in Patent Office: 425 Days
• Field of Search: 378/4, 378/114, 378/117, 378/118, 378/98, 378/207, 371/16, 371/20, 371/29, 364/414, 364/550, 364/551
• US Class Current: 378/4
• CPC Class Codes: A61B 6/035 Mechanical aspects of CT
• CPC Class Codes: A61B 6/10 Safety means specially adapted therefor
• CPC Class Codes: A61B 6/4488 Means for cooling A61B6/045 takes precedence
• CPC Class Codes: G05B 19/0428 Safety, monitoring G05B19/0423 takes precedence
• CPC Class Codes: G05B 2219/24018 Computer assisted repair, diagnostic
• CPC Class Codes: G05B 2219/24055 Trace, store a working, operation history
• CPC Class Codes: G05B 2219/24058 Remote testing, monitoring independent from normal control by pc
• CPC Class Codes: G05B 2219/2652 Medical scanner
• CPC Class Codes: H05G 1/26 Measuring, controlling or protecting measuring X-ray radiation G01T
• CPC Class Codes: H05G 1/54 Protecting or lifetime predictionoverload protection combined with control H05G1/46

Abstract

A plurality of medical electronic apparatae (A) including a CT scanner (B) or other medical imaging equipment are disposed at each of a plurality of remote locations. A diagnostic service system (C) monitors each CT scanner to create a malfunction history therefor. A central polling station (D) polls the diagnostic service system of each scanner to retrieve the diagnostic history thereof. The diagnostic service system includes a plurality of monitors (80, 82, 84, 86, 88) which monitor operating conditions and parameters of the scanner. The monitored operating conditions include the operating mode within the sequence of operating modes, operating parameters of an X-ray tube (12), and the operation of other scanner components. When a fault detection circuit (92) detects a malfunction, a latch array (90) immediately stores an indication of the condition monitored by the monitors. A read/write circuit (94) transfers the latched condition data to a malfunction history memory (96). Data from the malfunction history memory may be displayed on diagnostic service display (104) or transmitted by a modem (112) to the central polling station.

Claims

1. A CT scanner comprising:

an x-ray tube mounted to rotate an x-ray beam around a scan circle, the x-ray tube including an evacuated envelope, a rotatable anode disposed in the envelope, means for rotating the anode, and at least one cathode disposed in the envelope;

an anode rotating means power supply for supplying motive power to the anode rotating means;

a cathode power supply for heating the cathode;

a tube power supply for providing an electrical potential between the anode and the cathode;

a cooling fluid means for circulating a cooling fluid adjacent the evacuated envelope to limit the heating of the x-ray tube;

an x-ray detector array disposed across the scan circle from the x-ray tube to receive x-rays which have traversed a region of interest of a patient;

an x-ray beam rotating means for rotating the x-ray beam around the scan circle;

an image reconstruction means for reconstructing image representations, the image reconstruction means including means for receiving information from the detector array regarding the intensities of the x-rays which have traversed the region of interest and reconstructing an image of a cross section of the patient;

a scanner control for controlling the anode power supply, the cathode power supply, the tube-power supply, the cooling fluid means, the anode rotating means, the image reconstruction means and a sequence operating mode thereof;

an anode monitor for monitoring whether motive power is being supplied to the anode rotating means;

a cathode monitor for monitoring the cathode power supply;

a tube power monitor for monitoring the electrical potential between the anode and the cathode;

a cooling fluid monitor for monitoring the cooling fluid;

a scanner sequence control monitor for monitoring the controlled operating mode;

a latch array including at least one latch operatively connected with each monitor for selectively latching in temporary storage corresponding monitored conditions to create a "snap shot" of the monitored operating conditions;

a fault detection means for detecting malfunctions, the fault detection means being operatively connected with the monitors for determining malfunctions from the monitored conditions and being operatively connected with the latch array for causing each latch to latch into storage the corresponding monitored condition as monitored by the monitor to which it is connected before the detected malfunction cascades causing further changes of the monitored conditions, such that the snap shot of the state of the monitored conditions is taken when a malfunction is detected to aid diagnosis and repair; and

,

a malfunction history memory means for storing long term the monitored conditions latched by the latches in response to each of a plurality of detected malfunctions to create a malfunction history for the CT scanner including a plurality of snap shots of the monitored conditions recorded at the time of each malfunction, such that the malfunction history aids diagnosis and repair.

2. The CT scanner as set forth in claim 1 further including:

a central polling computer means for polling the malfunction history memory means of a plurality of CT scanners to retrieve the stored malfunction history therefrom and transfer the retrieved malfunction histories into a central location to facilitate diagnosis of malfunctions from the central location.

3. The CT scanner as set forth in claim 1 wherein the tube power supply includes a positive power supply for supplying the anode with a preselected positive voltage relative to a common ground and a negative voltage supply for supplying a preselected negative voltage to the cathode relative to the common ground, and wherein the tube power monitor monitors a balance between the positive and negative potentials supplied by the positive and negative power supply means for an imbalance therebetween.

4. A diagnostic service system for CT scanners, the system comprising:

an anode monitor for monitoring an x-ray tube anode;

a cathode monitor for monitoring an x-ray tube cathode;

a tube power monitor for monitoring a selected electrical potential applied between the anode and the cathode;

a latch array including a plurality of latches, at least one latch being operatively connected with each of the anode, cathode, and tube power monitors for continuously receiving a corresponding monitored condition until a latch clock signal is received, each latch being responsive to a latch clock signal to store the corresponding monitored condition in memory before a malfunction cascades and affects other monitored conditions;

a fault detection and latching means for detecting malfunctions, the fault detection means being operatively connected with the anode, cathode, and tube power monitors for determining malfunctions from the monitored conditions, the fault detection means being operatively connected with the latch array for providing the latch clock signal to each latch to latch the monitored condition of the corresponding monitor in memory;

a malfunction history memory means for storing the monitored conditions, the memory means being operatively connected with the latch array such that monitored conditions stored in the latch are selectively transferred to the memory means for each of a plurality of detected malfunctions to create a malfunction history; and

,

a display means for displaying selected portions of the malfunction history.

5. The system as set forth in claim 4 further including a sequence monitor for monitoring operating modes of the scanner, the latch array including a latch which is operatively connected with the sequence monitor for selectively latching an indication of the monitored operating mode when the malfunction was detected.

6. The system as set forth in claim 4 further including:

a central polling computer means for polling the malfunction history memory means of each of a plurality of diagnostic service systems to retrieve the malfunction histories therefrom.

7. The system as set forth in claim 6 further including modems interconnected with the central polling computer means and with the malfunction history memory means such that data is transmitted therebetween.

8. The system as set forth in claim 6 further including an automatic diagnosis means for comparing retrieved malfunction histories with preselected malfunction histories which are indicative of one or more malfunctions.

9. A medical diagnostic scanner system comprising:

a source of penetrating radiation;

a detector means for detecting radiation that has traversed an examination region and generating electronic detector data indicative thereof;

an image reconstruction means for reconstructing an image representation from the electronic detector data;

a monitor means for monitoring each of a plurality of scanner operating conditions;

a latch array including a plurality of latches operatively connected with the monitor means, each latch being responsive to a clock signal to freeze the corresponding one of the monitored conditions in temporary storage;

a fault detection means for detecting malfunctions, the fault detection means being operatively connected with the monitor means for determining malfunctions from the monitored conditions, the fault detection means being operatively connected with the latch array for clocking each latch to latch and freeze the corresponding monitored condition in response to a determined malfunction such that the latch array captures a snap shot of each monitored condition before a detected malfunction can cascade and affect other monitored conditions;

a malfunction history means for storing the monitored conditions, the malfunction history means being operatively connected with the latch array such that monitored conditions latched in temporary storage in the latch are selectively transferred to the malfunction history means for each of a plurality of detected malfunctions to create a malfunction history; and

,

a display means for displaying selected portions of the malfunction history.

10. The system as set forth in claim 9 wherein the monitor means includes a monitor for monitoring at least one of (i) an X-ray tube anode operating condition, (ii) an X-ray tube cathode operating condition, (iii) an X-ray tube operating voltage, and (iv) a mode in which the scanner was operating when the malfunction was detected.

11. A medical diagnostic scanner which cycles through a sequence of operating modes comprising:

means for non-invasively examining a portion of a patient disposed in an examination region;

a detection means for producing electronic detector data indicative of the non-invasive examination;

an image reconstruction for reconstructing an image representation from the electronic data;

a monitor means for continuously monitoring which of the operating modes the scanner is in;

a latch means operatively connected with the monitor means for selectively latching the monitored operating mode;

a fault detection means for detecting a scanner malfunction, the fault detection means being operatively connected with the latch means for causing the latch means to latch the monitored operating mode before the detected malfunction cascades and affects other monitored conditions in response to a detected malfunction such that a snap shot of the operating mode when the malfunction occurred is latched; and

,

a display means for displaying an indication of the latched operating mode, such that the operating mode when the malfunction occurred is retrievable to assist in diagnosing a cause of the malfunction.

12. A method of monitoring a medical electronic apparatus for malfunctions, the method comprising:

(a) continuously, transiently monitoring a plurality of ambient operating conditions of the medical electronic apparatus;

(b) in response to a detected malfunction, instantaneously freezing each of the ambient monitored conditions in temporary storage;

(c) transferring the frozen monitored conditions from temporary storage into a memory to create a malfunction history, such that the frozen monitored conditions provide a snap shot of the monitored conditions at each failure.

13. The method as set forth in claim 12 wherein the medical electronic apparatus cycles through a plurality of operating modes and wherein the monitoring step includes monitoring the operating mode such that the operating mode when the malfunction is detected is latched and transfered to the memory as part of the malfunction history.

14. The method as set forth in claim 12 wherein the monitoring step includes monitoring an apparatus operating mode.

15. The method as set forth in claim 12 wherein the monitoring step includes monitoring x-ray tube operating parameters.

16. The method as set forth in claim 12 further including:

repeating steps (a), (b), and (c) for each of a plurality of medical electronic apparatae;

at selected intervals, polling the memory of each apparatus from a central location to retrieve the malfunction history; and

,

storing and updating the retrieved malfunction history of each apparatus at the central location wherein the monitoring step includes monitoring a CT scanner x-ray tube operating parameters.

17. The method as set forth in claim 16 further including at the central location analyzing the retrieved malfunction histories and scheduling repair and maintenance in accordance therewith.

18. A method of monitoring a CT scanner for malfunctions, which CT scanner includes an x-ray tube mounted for rotation about a scan circle, the x-ray tube including an evacuated envelope, a rotatable anode disposed in the envelope, means for rotating the anode, and at least one cathode disposed in the envelope, an anode rotating means power supply for supplying motive power to the anode rotating means, a cathode power supply for providing a heating current to the cathode, a tube power supply for providing an electrical potential between the anode and the cathode, an x-ray detector array disposed across the scan circle from the x-ray tube to receive x-rays which have traversed a region of interest of a patient, rotating means for rotating the x-rays around the scan circle, an image reconstruction means for reconstructing image representations, the image reconstruction means including means for receiving information from the detector array about intensities of the x-rays which have traversed the region of interest and reconstructing an image of a cross section of the patient, the method comprising:

monitoring the anode to determine whether the anode is rotating;

monitoring the cathode to determine whether a selected heating current is provided thereto;

monitoring the electrical potential between the anode and the cathode to determine whether a selected electrical potential is applied therebetween;

causing an indication of the monitored anode rotation, the monitored cathode current, and the monitored tube power electrical potential to be stored temporarily in response to detecting a malfunction and before the detected malfunction cascades and changes the monitored anode rotation cathode current, and electrical potential indication; and

,

transferring the temporarily stored indication of monitored anode rotation, cathode current, and the tube electrical potential to long term memory after each of a plurality of malfunctions to create a malfunction history.

19. The method as set forth in claim 18 further including transferring the stored malfunction histories to a central location at selected intervals.

20. The method as set forth in claim 18 wherein the CT scanner cycles through a plurality of operating modes and further including monitoring the scanner operating mode, storing the monitored mode in response to the detected malfunction, and recording the monitored mode.

21. The method as set forth in claim 18 further including in response to the detected malfunction, causing the scanner to shift into a phase down mode in which the potential between the anode and cathode is removed and the cathode is cooled at a controlled rate.