Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
  • A61B6/54—Control of apparatus or devices for radiation diagnosis
  • A61B6/542—Control of apparatus or devices for radiation diagnosis involving control of exposure
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
  • A61B6/40—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for generating radiation specially adapted for radiation diagnosis
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
  • A61B6/42—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for detecting radiation specially adapted for radiation diagnosis
  • A61B6/4266—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for detecting radiation specially adapted for radiation diagnosis characterised by using a plurality of detector units
• • A61B6/512—
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
  • A61B6/54—Control of apparatus or devices for radiation diagnosis
  • A61B6/548—Remote control of the apparatus or devices
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
  • A61B6/56—Details of data transmission or power supply, e.g. use of slip rings
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
  • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
  • G01T1/02—Dosimeters

Definitions

• X-ray imaging is commonly used as a diagnostic too! in dental settings.
• film was used as the x-ray detector.
• the film is inserted into the patient's mouth behind the teeth and the outside of the patient's jaw is exposed to a pulse of x-rays.
• the teeth absorb the x-rays, and hence, create contact images of the teeth on the film which are then used by (he dentist to diagnose the state of the teeth.
• This system had a number of problems that have been overcome to some degree by replacing the film with a digital image sensor.
• a scintillator is used to convert the x-rays to visible light.
• the light is collimated by a fiber optic bundle, and a CMOS image sensor of substantially the same type as used hi digital photography is used to detect the generated light mat leaves the collimator.
• the dynamic range of the film is typically less than a factor of 100. That is, the ratio of the highest light level that can be recorded without saturating the film to the lowest level mat can be detected is of the order of 100. This dynamic range is sufficient to provide useable images if the exposure is correctly set.
• Digital sensors also require substantially less x -ray exposure to form a usable image.
• digital sensors hold the promise of reducing this exposure.
• this promise has only partially been achieved by current digital x-ray systems.
• the x-ray generating system is independent front the imaging sensor.
• a dentist who desires to switch from film to a digital sensor typically uses the dentist's existing x-ray system and merely reduces the exposure to a level that provides satisfactory images, The technician places the digital sensor in the patient's mouth and then triggers the x-ray system to provide a pulse of x-rays that, is sufficient to provide the desired image.
• the digital sensor sends the image to a computer that processes the image and stores the data in the electronic patient information system.
• the present invention includes an x-ray imaging system and a method for retrofitting existing x-ray generators to allow those generators to be controlled by a digital x- ray imaging system.
• the x-ray imaging system includes an imaging array and an image controller.
• the imaging array is configured to be positioned within a patient's mouth, the imaging array acquiring an image of the patient's teeth when the patient's head is illuminated with x-rays.
• the imaging array includes an x-ray dosimeter that provides an x-ray exposure signal indicative of an x-ray exposure received by the imaging array.
• the image controller is coupled to the imaging array and receives the x-ray exposure signal, the image controller includes a first wireless link that controls an x-ray generator by initiating a pre-programmed x-ray exposure.
• the pre-programmed x-ray exposure is less than the minimum x-ray exposure needed to provide a satisfactory image of the patient's teeth.
• the image controller repeatedly initiates the pre-programmed x-ray exposure until the exposures taken together provide a satisfactory image of the patient's teem.
• the image controller includes a second wireless link that interrupts the pre-programmed x-ray exposure.
• the image controller interrupting the pre-programmed x-ray exposure in response to the x-ray exposure signal indicating that an exposure sufficient to provide a satisfactory image of the patient's teeth had been received.
• the image controller is manufactured by a first commercial entity and the system includes an x-ray generator manufactured by a second commercial entity that is different from the first commercial entity, the x-ray generator is sold separately as a stand alone unit tor x-ray imaging.
• the first wireless link is manufactured by a first commercial entity and the system includes an x-ray generator manufactured by a second commercial entity that is different from the first commercial entity, the x-ray generator is sold separately as a stand alone unit tor x-ray imaging.
• the second wireless link controls a wireless controlled switch that interrupts the generation of x-rays by the x-ray generator.
• the second wireless link interrupts a power line that supplies power to an x-ray generating tube in the x- ray generator.
• Figure 1 illustrates the arrangement of the various components in a dental x- ray analysis of a patient's teeth.
• Figure 2 illustrates one embodiment of an x-ray exposure system according to the present invention.
• Figure 3 illustrates another embodiment of a digital x-ray system according to the present invention.
• FIG. 1 illustrates the arrangement of the various components in a dental x-ray analysis of a patient's teeth.
• an imaging sensor 21 is placed in the patient's mouth so that x-rays from an x-ray source 22 will pass through the patient's teeth 23 and be detected by the imaging array.
• the imaging array is controlled by image controller 24 that processes the data from imaging sensor 21 to provide an image of the patient's teem that is stored in an electronic file associated with the patient X-ray source 22 is controlled from a separate X-ray controller 25 that includes a high voltage power supply that applies an acceleration potential that cause electrons to strike a metal target to generate the x-rays.
• the x-ray source was purchased by the dentist to be used in a film-based diagnostic system.
• the digital imaging system is typically purchased as a replacement for the film component of the old x-ray system and is completely independent of the older x-ray source.
• the old x-ray system is operated by manually closing a switch 27 that initiates a high voltage pulse of the appropriate length to provide the desired x-ray exposure.
• a switch 27 that initiates a high voltage pulse of the appropriate length to provide the desired x-ray exposure.
• Prior art systems in which imaging sensor 21 is controlled in response to the generation of x-rays are known. In such systems, the imaging array is placed in a ready state prior to switch 27 being closed by an operator entering the appropriate command to image controller 24. In these systems, imaging sensor 21 includes a dose measuring sub-system that detects the start of the x-ray pulse. Systems based on measuring currents generated in the imaging sensor itself or a secondary sensor associated with imaging sensor 21 are known to the art. In these systems, the imaging array is reset at the start of the x-ray pulse.
• the image is accumulated until the x-ray source is turned off.
• the imaging array can either detect the cessation of the x-ray exposure using the same system that detected the start of the pulse of x-rays or merely wait a predetermined length of time. In either case, the image is readout and processed after the x-ray exposure has been completed.
• the x-ray exposure is determined by the settings on the X-ray controller.
• the settings are typically not varied to account for different patients' facial absorption of the x-rays, etc.
• the settings are typically set to some safe setting that ensures a sufficient exposure for all patients. Accordingly, many patients receive a larger exposure man necessary.
• FIG. 2 illustrates one embodiment of an x-ray exposure system according to the present invention.
• the trigger switch that initiated an x-ray burst from x-ray head 41 has been replaced by a remote controllable switch 42. Since the location of remote controllable switch 42 is not necessarily close to image controller 51 that controls imaging array 52, remote controllable switch 42 preferably communicates with image controller 51 via a wireless communication link 53 such that a cable is not needed between remote controllable switch 42 and image controller 51. Remote controllable switch 42 allows image controller 51 to trigger a pulse of x-rays.
• Imaging array 52 includes an x-ray dose detector that measures the dose of x- rays received at imaging array 52. Any of a number of systems for measuring the x-ray dose can be utilized. For example, x-rays striking the imaging array are known to give rise to currents that can be measured. For example, in one a guard ring that is normally used to shield the imaging array from transients generated by other circuitry in a CMOS imaging array is used as an x-ray detector by measuring the current that flows between that guard ring and a power rail. In another example, the imaging array is readout after each pulse of x-rays and the total sub-exposure determined by examining the sums of the signals from a predetermined set of pixels.
• the x-ray source is operated in a series of shot pulses.
• the exposure of each pulse is set by controls on the x-ray source.
• these controls are set such that the pulse delivered in response to each trigger pulse is a small fraction of the required dose to provide an image of the desired quality.
• each pulse could be set to one-tenth of the expected dose r so that a total of about ten pulses are needed to provide the exposure.
• image controller 51 initializes imaging array 52 and sends the first pulse of x-rays.
• Image controller 51 t hen reads out the dosimeter and determines the number of pulses that will be needed to provide the correct exposure.
• Image controller 53 then pulses the x-ray source for the determined number of pulses.
• image controller 51 reads out the dosimeter at one or more intermediate points in the exposure to verify that the initial estimate of desired exposure time was correct.
• the x-ray dose is set to a small fraction of the estimated correct dose and the dosimeter is readout.
• Image controller 51 then instructs the operator to set the x-ray exposure to a value determined by that dose.
• the imaging array is men reset and the x-ray system triggered for the calculated exposure time.
• This embodiment eliminates the dead time between x-ray pulses; however, it requires more skill and time on the part of the operator.
• the remote controllable trigger switch of the present invention provides a simple method for upgrading a conventional x-ray source for use with the digital x-ray system.
• the switch typically makes a connection between two contacts that are held at a potential relative to one another.
• This potential difference can be tapped to power the radio link between the remote controllable switch and the controller of the digital x-ray system. If the power available from this source is insufficient, a battery that is charged from the source over a long period of time can be utilized to power the wireless link.
• the radio controllable switch that provides the link between die image controller and the x-ray controller is inserted into the x- ray controller by replacing the x-ray trigger switch that is commonly used in existing x-ray generating systems. Since the trigger switch does not set the length of the x-ray pulse, some other strategy is needed to turn off the x-ray generator when the patient has received the desired level of exposure.
• a second radio controlled switch is inserted within, the x-ray generation system to interrupt the high voltage to the x-ray head. This second switch allows the imaging controller to terminate the exposure at the appropriate time without significantly altering the underiying electronics of the x-ray generation system.
• FIG. 3 illustrates another embodiment of a digital x-ray system according to the present invention.
• those elements of digital x-ray system 60 that serve functions analogous to elements of digital x-ray system 40 discussed above have been given the same numerical designations as the elements of digital x-ray system 40 and will not be discussed in detail here.
• Digital x-ray system 60 is based on the observation that x-ray head 41 typically includes an x-ray generating tube mat is powered by a signal source that causes electrons to be accelerated into a metal target.
• the signal source typically includes a high voltage power supply line that provides the potential for the acceleration.
• the x-ray output can be terminated by interrupting this high voltage power line using a second radio remote controlled switch 67 that is operated by a second wireless link 64.
• image controller 61 controls the x-ray process and provides the user interface for the control of mat process.
• the x-ray controller 25 is set to provide an exposure that is sufficient to ensure that all patients can receive at least the desired x-ray illumination if the entire exposure is allowed to proceed.
• image controller 61 uses the wireless interface between antennas 63 and 65 to trigger the x-ray generator with wireless link 64 closed. After image controller 61 detects that the desired x-ray exposure has been obtained, image controller 61 opens radio remote controlled switch 67 using the wireless link between wireless link 64 and antenna 65. The remainder of the programmed exposure in x-ray controller 25 does not generate x-rays.
• x-ray generators typically, these x-ray generators are made by a different manufacturer or commercial entity than the manufacturer of the digital image controller.
• the present invention provides a method for slaving the x-ray generator to the digital imaging system that requires only minimal changes to the x-ray generator. These changes can be provided on site in a dental office that already has an x-ray generator or by the manufacturer of digital x-ray imaging system that then sells a complete system to the dentist.

Applications Claiming Priority (1)

Publications (2)

Family

ID=65276514

Family Applications (1)

Country Status (1)

Cited By (1)

Family Cites Families (3)

• 2017
  • 2017-02-21 EP EP17736547.5A patent/EP3399906A4/de not_active Withdrawn

Also Published As

Similar Documents

Legal Events