A multi-optical transmission calibration system and method for CT machine

Abstract

The present application provides a multi-optical transmission calibration system and method for a CT machine, which relates to the field of communication technology of CT equipment. The transmission calibration system is composed of a transmitting end CT device end transmitting light signals installed on the inner wall of the CT rotor and a wide-angle receiving optical lens group, a micro-compensation mirror, a spot monitoring camera, a wavelength spectroscope, a micro-nutation compensation mirror, a communication fiber coupler, and a fiber power detector at the receiving end. The calibration process of the three stages of initialization establishment of the light emission and receiving end on the CT machine rotor, dynamic stabilization of the light spot, and dynamic fiber coupling is completed, providing a guarantee for the establishment of stable transmission of optical information of the rotating joint of the CT machine.

Description

Technical Field

[0001] The invention belongs to the field of medical equipment communication information technology, and relates to a multi-optical path transmission calibration system and method for a CT machine. Background Art

[0002] CT (Computed Tomography) is a computer tomography scan that uses precisely collimated X-ray beams, gamma rays, ultrasound, etc., together with extremely sensitive detectors to perform cross-sectional scans one after another around a certain part of the human body. It has the characteristics of fast scanning time and clear images, and can be used to detect a variety of diseases. According to the different rays used, it can be divided into: X-ray CT (X-CT) and gamma-ray CT (γ-CT), etc.

[0003] CT equipment workflow: The scanning part consists of an X-ray tube, a detector, and a scanning frame. The human body is rotated and scanned, and the X-ray detector receives the signal; then the information data collected by the scan is transmitted to the computer system for storage and calculation; finally, the CT image is displayed through computer processing and reconstructed images. However, according to the principle of CT, images must be obtained by scanning, and now it has developed into spiral CT scans. Therefore, there is a problem of information transmission of rotating joints. At this stage, capacitive non-contact information transmission is used. This transmission method has a limited rate and requires the development of a sufficiently large radiating antenna, which has requirements for volume and power consumption.

[0004] 2003 was a period of rapid development of multi-slice spiral CT. At the annual meeting of the North American Radiology Society, 32-slice and 40-slice spiral CT were launched by different manufacturers. In 2004, 64-slice spiral CT became a new highlight in the development of CT. GE, Philips, Siemens, and Toshiba successively released 64-slice CT. The advent of 64-row spiral CT ushered in a new era of non-invasive diagnosis of cardiovascular diseases. It can complete heart scans in less than 5 seconds, and heart CT has become a clinical routine. Now the single-cycle scanning time of multi-slice spiral CT has been shortened to sub-second level. Multi-slice spiral CT has been widely used in many fields such as angiography imaging, brain perfusion imaging, and heart imaging. In addition, it also plays an important role in radiotherapy planning and virtual endoscopy technology. In 2004, Toshiba took the lead in successfully developing 256-slice spiral CT. Since 2005, a large number of high-end medical CTs have been successfully developed. Its main representatives are: Siemens' dual-source spiral CT, Philips' 256-slice ultra-fast CT, Toshiba's 320-row 640-slice CT and GE's Gem CT.

[0005] In the future, CT data transmission will mainly be based on optical transmission, and the data rate will be further increased to 50Gbps due to the overall technical improvement of CT products. Currently, this transmission rate can only be achieved by optical transmission. Shreveling and Mogo are both conducting research on optoelectronic transmission. Shreveling and Mogo have successively launched 10Gbps CT slip ring products.

[0006] The digital diagnosis and treatment equipment R&D project "256-row 16cm high-definition, high-speed, large-volume medical CT system and core technology R&D" is developing a 10Gbps optical transmission system, which is applied to arrange 12 transmission channels on the CT host and use the circular motion of the reflector cavity for reception. The complexity of the system has a relatively large impact on the existing CT equipment and the position of the hollow space of the CT.

[0007] In the prior art, there is no multi-optical path transmission calibration system and method for the rotating joints of CT equipment. Summary of the invention

[0008] The technical problem solved by the present invention is that the amount of data collected by CT equipment is increasing at this stage, and data transmission relying on single-channel capacitive wireless contact has gradually reached a bottleneck, and the demand for higher-speed and low-cost transmission has become obvious. The present invention solves the problem of multi-channel high-speed CT equipment detection information transmission. Without changing the internal layout of the CT host, the CT equipment is installed with a standardized multiplexing interface, and the high-speed data is transmitted to a location outside the host using an optical carrier for reception. During the reception process, the installation calibration process of the transceiver needs to be carried out first.

[0009] The embodiment of the present application provides a multi-optical path transmission calibration system for a CT machine, which relates to the field of communication technology of CT equipment. It includes an optical signal transmitting end and an optical signal receiving end. The transmitting end contains a laser light source, an optoelectronic modulator, a beam collimator, a WIFI transceiver and supporting structures; the optical signal receiving end contains a wide-angle receiving optical lens group, a micro-compensation mirror, a spot monitoring camera, a wavelength spectrometer, a micro-nutation compensation mirror, a communication fiber coupler, a fiber power detector and a fixed mounting platform. The optical signal transmitting end installed on the inner wall of the CT rotor transmits a signal, which is transmitted over a certain distance to reach the optical signal receiving end, and the optical signal receiving end is in the middle position of the fixed mounting platform connected to the CT stator connecting rod. The beam calibration process is performed before the transceiver communication is established. The present application completes the calibration process of the three stages of initialization establishment of the optical transmitting and receiving end on the CT machine rotor, dynamic stabilization of the spot and dynamic fiber coupling, and provides a guarantee for the establishment of stable transmission of optical information of the rotating joint of the CT machine.

[0010] Optionally, a laser communication transmitting system is also included, which includes an integrated light source, an optoelectronic modulator, a spectroscope, a beam collimator and a micro position detection module, which are specifically installed on the rotor of the CT host. The original data obtained by X-ray detection or the data after microwave modulation can be loaded onto the light wave using optoelectronic direct modulation technology, and the data loading is carried out according to instructions. The spectroscope combines the modulated light beams of multiple laser sources with the calibration beams. The micro position detection module detects whether there is an indication of the received traceback light. The different apertures are installed closely in parallel with the beam collimator.

[0011] Optionally, a wide-angle receiving lens group is included to receive the light beam emitted by the laser communication transmitting system. An optical corner reflector is placed in the middle of the protective lens in the wide-angle lens group, and a transmissive film is coated on the periphery. The concentrated emitted light is projected onto a tiny compensation mirror. The light beam incident on the corner reflector is reflected along the original optical path to a micro position detection module of the laser communication transmitting system.

[0012] Optionally, the spot monitoring camera receives the calibration light separated by the beam splitter after the light reflected by the micro compensation mirror. According to the laser communication transmitting system, as the CT host rotates, the light spot received by the spot monitoring camera will also rotate, and the micro compensation mirror is used to stabilize the light spot on the center of the rotating light spot ring.

[0013] Optionally, a micro-nutation compensation mirror is included to reflect the communication light beam separated by the beam splitter to the communication optical fiber coupler, and the detection value of the optical fiber power detector is dynamically maximized by using the nutation coupling method.

[0014] Optionally, a multi-optical transmission calibration method for a CT machine is also included, and the specific steps are as follows: When the work starts, the laser communication transmission system only starts the calibration beam emission, and after projecting it to the wide-angle receiving lens group of the receiver, the corner reflector in the receiving lens group will reflect part of the light back to the micro position detection module in the laser transmission system. As the CT host rotates, the intensity of the position detection module is kept stable, indicating that the transceiver beams have been aligned, and then the wifi command is used to start the unmodulated communication beam, and the closed-loop control of the tiny compensation mirror and the spot monitoring camera is used to make the spot stable and unchanged, and then the closed-loop control of the tiny nutation compensation mirror and the fiber power detector is used to suppress environmental vibration, the instability of the center of mass of the circular ring light ring and other factors, and improve the fiber coupling efficiency. In this way, the calibration process of the multi-optical transmission of the CT machine is completed.

[0015] Through laser wireless communication, the high-speed data on the rotor of the CT machine is transmitted to a fixed position for reception, so as to achieve the purpose of optical transmission of the rotating joint of the CT machine. First, the optical corner reflector in the wide-angle receiving system is used to align the transceiver module, and the closed-loop control of the micro-compensation mirror and the spot monitoring camera is used to eliminate the centroid change of the circular rotating spot, so that it is stable at the center of the circle. Then, the closed-loop control of the micro-nutation compensation mirror and the fiber power detector is used to eliminate the instability of the spot and the vibration of the environment, and improve the fiber coupling efficiency. Such a calibration process makes the optical transmission stable and meets the requirements of multi-channel optical transmission.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The present invention does not change the internal layout of the CT host, but only installs an optical transmission module with a standard interface, so that the CT acquisition data can be transmitted at a high speed, and the initial alignment method of the retrospective light is used to indicate the initialization of the transmission and reception. This calibration system can be equipped not only for the currently used CT equipment, but also for the CT equipment under development.

[0018] (2) The present invention utilizes a micro-compensation mirror and a closed-loop control of a light spot monitoring camera to eliminate the change in the center of mass of the circular rotating light spot, so that the light spot at the center of the circle is stable. The light spot at the center of the circle is unstable, and then utilizes a micro-nutation compensation mirror and a closed-loop control of an optical fiber power detector to eliminate the instability of the light spot and the influence of environmental vibration, thereby ultimately improving the optical fiber coupling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0020] Figure 1 is a diagram of a multi-optical transmission calibration system provided by an embodiment of the present invention;

[0021] Figure 2 is a flow chart of a multi-optical transmission calibration method provided by an embodiment of the present invention;

[0022] Figure 3 It is a calibration system diagram of a multi-optical path wavelength division multiplexing communication method provided by an embodiment of the present invention; DETAILED DESCRIPTION

[0023] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0024] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0025] like Figure 1 The multi-optical transmission calibration system diagram for CT machine provided by the embodiment of the present invention is shown, which is applicable to a multi-optical transmission calibration system for CT machine, characterized by comprising: CT host 1, laser communication transmission system 2, wide-angle receiving lens group 3, micro compensation mirror 4, spectroscope 5, spot monitoring camera 6, micro nutation compensation mirror 7, communication fiber coupler 8, fiber power detector 9, optical corner reflector 10, micro position detection module 11, fixed mounting platform 12 and communication receiving module 13. Among them, the laser communication transmission system 2 is installed on the side wall of the scanning rotor of the CT host 1, and contains the transmission of multi-channel communication light beams, the transmission of calibration light beams and the micro position detection module of the back-tracking light, which multiplexes the X-ray detection and collection in the CT host 1 into one channel of original digital data, or has been converted into a microwave intermediate frequency signal modulated onto an optical carrier, or the X-ray multi-channel collection data is directly optically multiplexed and loaded onto the laser communication transmission system 2. In short, this module can be modified at will according to the design without being restricted by the system method. The emitted light beam is projected to the receiver, whose central axis is on the central Z axis of the CT host 1. The retrospective light of the optical corner reflector 10 installed at the front end of the wide-angle receiving lens group 3 determines whether the transceiver light beams have been aligned. This alignment method is used for calibration in the initialization process of the CT equipment communication transmission self-test. The micro position detection module 11 for determining the retrospective light is installed closely parallel to the beam collimator in the laser communication transmitting system 2 with different apertures. The divergence angle of the calibration beam is larger than that of the communication beam. The CT host 1 moves in a circle, and the presence or absence of the light spot is determined according to the micro position detection module 11 to adjust the direction of the laser communication transmitting system 2. This adjustment is relatively simple and will not be repeated.

[0026] The wide-angle receiving lens group 3 adopts a 360° panoramic imaging optical system and a telephoto convergence method. The light beam needs to be reflected by a tiny compensation mirror 4. The reflected light beam then passes through a wavelength spectrometer 5 to separate the calibration light beam and transmit it to the spot monitoring camera 6. The focus of the calibration light beam is at the spot monitoring camera 6. The reflected light beam is a communication light beam of multiple bands of 1.3um, 1.5um and 1.06um. The spot projected by the calibration light beam on the monitoring camera 6 is calculated, and the center of mass of the spot is calculated. According to the circular motion of the spot, the center of mass is connected into a circular ring, and the center of the circle is calibrated according to the circular ring. Due to many engineering construction factors such as the installation accuracy of the receiver and the flatness accuracy of the fixed mounting platform 12, the center of the circle is not very fixed. Therefore, the tiny compensation mirror 4 is adjusted to make the light spot dynamically stable at the center of the circle. The uncertain axis angle corresponding to the light spot at the center of the circle is α.

[0027] The micro-nutation compensation mirror 7 utilizes the fiber-coupled nutation method. First, the spiral scan is started, and the axial angle of the scan is 1.5α. The light coupled into the communication fiber coupler 8 is then detected by the fiber power detector 9 to detect the coupled optical power until the maximum optical power is reached. In this way, the influence of environmental vibration, temperature and humidity changes, etc. on the optical coupling can be reduced.

[0028] The demand for CT data transmission will become increasingly higher, and the optical communication used in it is Figure 3 The wavelength division multiplexing shown, the wavelength splitter 5 continuously decomposes the parallel multi-wavelength nutation coupling mode, can meet the needs of higher rate CT data transmission. Of course, more efficient bandwidth communication methods are also applicable in this system. This system realizes the calibration process before the establishment of the new optical channel, and has little relevance to the communication modulation and demodulation method adopted.

[0029] like Figure 2 The optical transmission flow chart of the rotating joint of the CT device provided by the embodiment of the present invention is applicable to a multi-optical path transmission calibration method for a CT machine. The transmitter of this system is on the rotor of the CT host 1, and the receiver is on the Z axis of the CT host. Therefore, there is a calibration process of the light beam in a different place. The calibration process must be required before the complete communication is established. The specific implementation steps are as follows:

[0030] (1) Work starts, such as Figure 3 As shown, the laser communication transmitting system 2 has been installed on the rotor of the CT host 1. The WiFi command notifies to start transmitting the calibration beam. The divergence angle of the beam is relatively large compared to the communication beam. The wavelength of the calibration beam is in the 800nm ​​band. The transmitting beam is projected onto the protective mirror of the wide-angle receiving lens group.

[0031] (2) The projected light beam is partially traced back at the optical corner reflector 10, the size of the corner reflector is 6.2 mm. The laser communication transmitting system 2 is adjusted to make the micro position detection module 11 have light if there is no light when receiving the traced light. Then the WiFi command notifies to start the laser unmodulated communication beam, and the CT host 1 is also turned on and rotated.

[0032] (3) The calibration light beam and the communication light beam pass through the wavelength spectrometer 5. The transmitted 800nm ​​calibration light and the reflected light beam are communication light beams of multiple wavelengths of 1.3um, 1.5um and 1.06um. The spot monitoring camera 6 calibrates the circular ring of the spot along with the center of mass of the spot, thereby determining the uncertain area of ​​the center position. The micro compensation mirror 4 adopts a MEMS two-dimensional rotating mirror with a resonant frequency of 5KHz. The rapid rotation of the mirror causes the angle of the beam to change, thereby stabilizing the spot to the uncertain area of ​​the center position.

[0033] (4) When the light spot has reached the uncertainty area of ​​the light spot, the corresponding axial uncertainty angle is α, and the micro-nutation compensation mirror 7 is turned on. Within the axial angle range of 1.5α of the light spot monitoring camera 6, a spiral scan from the inside to the outside of the axial direction is started, and the scanning pitch is 3urad. The micro-nutation compensation mirror also uses a MEMS mirror with a frequency of 5kHz. The optical fiber power detector 9 continuously detects the optical power and memorizes the maximum value position, and then uses this as the axial angle center to perform a spiral scan from the inside to the outside. The scanning range is to ensure that the power of the optical power detector 9 is maximized. Such repetition can ensure the stable coupling efficiency of the optical power.

[0034] (5) Then the WiFi command notifies to start the laser modulation communication beam, and the CT host 1 can collect data and work normally, and then transfer to (3).

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A multi-optical transmission calibration system for CT machines, which solves the problem of real-time data transmission during medical CT scanning, characterized in that include: A CT host (1), a laser communication transmitting system (2) including a micro position detection module (11), a wide-angle receiving lens group (3), a micro compensation mirror (4), a beam splitter (5), a light spot monitoring camera (6), a micro nutation compensation mirror (7), a communication optical fiber coupler (8), an optical fiber power detector (9), an optical corner reflector (10), a fixed mounting platform (12) and a communication receiving module (13); The laser communication transmitting system (2) installed on the CT host (1) transmits a calibration beam and a communication beam. The light is irradiated to the optical corner reflector (10) at the receiving end and is traced back to the micro position detection module of the CT host. The micro position detection module (11) determines whether there is a traced light. The calibration beam and the communication beam emitted by the laser communication transmitting system (2) are irradiated to the wide-angle receiving mirror group (3) of the receiving party, and after being converged, they reach the spectroscope (5), transmit the calibration beam, and emit the communication beam. The spot monitoring camera (6) is used to monitor the converged spot of the calibration beam, and then the spot is closed-loop controlled with the micro compensation mirror (4) to the center of the circular ring. The communication beam is then reflected by the micro nutation compensation mirror (7), so that the beam enters the communication optical fiber coupler (8). The power detected by the optical fiber power detector (9) forms a closed loop with the micro nutation compensation mirror (7), so that the optical power of the beam coupled into the communication receiving module (13) is maximized in real time.

2. The multi-optical transmission calibration system for a CT machine according to claim 1, characterized in that: The laser communication transmitting system (2) comprises an integrated light source, an optoelectronic modulator, a beam collimator and a micro position detection module (11). The optical communication transmitting system (2) is installed on the rotor of the CT host (1). The original data or microwave modulated data obtained by the X-ray detection of the CT host (1) is loaded onto the light wave by using the optoelectronic direct modulation technology. The beam splitter combines the modulated beams of the multi-channel laser sources with the calibration beams, and then collimates them into nearly parallel beams through the beam collimator. After the beams reach the optical corner reflector (10), the beams are traced back to the micro position detection module (11). The micro position detection module (11) for determining whether there is a traced light is installed in close parallel with the beam collimator in the laser communication transmitting system (2) with different apertures.

3. The multi-optical transmission calibration system for CT machine according to claim 1, characterized in that: The wide-angle receiving lens group (3) receives the light beam emitted by the laser communication transmitting system (2); an optical corner reflector (10) is placed in the middle of the protective lens in the wide-angle lens group, and a transmission film is coated on the periphery to converge the emitted light and project it onto the micro compensation mirror (4); the light beam incident on the corner reflector is reflected along the original optical path to the micro position detection module (11) of the laser communication transmitting system (2).

4. The multi-optical transmission calibration system for a CT machine according to claim 1, characterized in that: The light spot monitoring camera (6) receives the calibration light reflected by the micro compensation mirror (4) and then separated by the beam splitter (5). Through the laser communication transmission system (2), as the CT host (1) rotates, the light spot received by the light spot monitoring camera (6) also rotates. The micro compensation mirror (4) is used to quickly compensate for the change in the beam angle, so that the light spot is stabilized at the center of the rotating light spot ring.

5. The multi-optical transmission calibration system for CT machine according to claim 1, characterized in that: The micro-nutation compensation mirror (7) reflects the communication light beam separated by the beam splitter (5) to the communication optical fiber coupler (8), and the light coupled into the communication optical fiber coupler (8) is then detected by the optical fiber power detector (9) to detect the coupled light power. The nutation coupling method is used to make the detection value of the optical fiber power detector (9) dynamically maximized.

6. A multi-optical transmission calibration method for a CT machine, characterized in that The method comprises: using the multi-optical path transmission calibration system as described in any one of claims 1 to 5, and the specific steps are as follows: When the work starts, the laser communication transmitting system (2) only starts the calibration beam emission. After projecting to the wide-angle receiving lens group (3) of the receiver, the corner reflector in the receiving lens group will reflect part of the light back to the micro position detection module (11) in the laser transmitting system. As the CT host (1) continues to rotate, the intensity of the micro position detection module (11) stabilizes, indicating that the receiving and transmitting beams have been aligned. After the laser communication transmitting system (2) is calibrated, the unmodulated communication beam is turned on using the wifi command. The closed-loop control of the micro compensation mirror (4) and the spot monitoring camera (6) stabilizes the spot in the uncertain area of ​​the center position. The closed-loop control between the micro nutation compensation mirror (7) and the optical fiber power detector (9) is then used to maximize the coupled optical power, thereby completing the calibration of the multi-optical transmission of the CT machine.

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