METHOD OF ADJUSTING SETTINGS OF A RADIATION IMAGE RECORDING SYSTEM

Abstract

A spatial change of a body part of an operator of a radiation image recording system is tracked and measured and setting(s) of the radiation image recording system are adjusted by an amount proportional or equal to the measured spatial change.

Claims

1-19. (canceled)

20. A method of adjusting settings of a radiation image recording system for recording a radiation image of a patient, the method comprising: performing a first action to start tracking a position of a body part of an operator of the radiation image recording system; performing a second action to stop tracking the position of the body part by performing a movement without contacting the radiation image recording system or the patient; measuring a spatial change of the body part between a time of starting the tracking and a time of stopping the tracking; and adjusting the settings of the radiation image recording system by an amount proportional or equal to the measured spatial change.

21. The method according to claim 20, wherein the settings include settings of a component of the radiation image recording system.

22. The method according to claim 21, wherein the component is at least one of a radiation source, a radiation collimator, a radiation source support, and a patient support table.

23. The method according to claim 20, wherein the settings pertain to settings of an application or settings of a workflow.

24. The method according to claim 20, wherein the first action and/or the second action includes one of a gesture by the operator, positioning of the body part of the operator at a predetermined location, generating an audio signal, and generating a voice command.

25. The method according to claim 20, wherein the tracking of the body part includes: recognizing the body part by registering a reference body part using a measured depth image; and computing and interpreting a similarity measure.

26. The method according to claim 20, wherein the tracking of the body part includes: recognizing the body part by skeletonization; and mapping the position of the body part on a default skeleton to an actual skeletonization derived from depth measurements.

27. The method according to claim 20, wherein the body part defines a two-dimensional area, and the method further comprises: detecting and measuring the two-dimensional area; and applying results of the measured two-dimensional area to a radiation collimator to define a collimation area.

28. The method according to claim 27, wherein the two-dimensional area is delimited by a square defined by the operator's hands and zooming of the two-dimensional area delimited by the hands is performed to increase or decrease the two-dimensional area and the setting of the radiation collimator to define the collimation area is adapted accordingly.

29. The method according to claim 20, wherein the first action and/or the second action includes at least two gestures by the operator performed in different directions; and one of the at least two gestures includes detecting parallel hands of the operator and changing a distance between the parallel hands to increase or decrease a setting of the radiation image recording system in a direction of the changing distance.

30. The method according to claim 20, wherein the tracking of the body part includes recording the position of the body part using at least one camera.

31. The method according to claim 30, wherein the at least one camera is a depth camera.

32. The method according to claim 20, further comprising: recording a current position of items in a radiation image recording room; and controlling movement of a component of the radiation image recording system taking into account the recorded current positions of the items so as to avoid collision of the component with the items in the radiation image recording room.

33. The method according to claim 20, further comprising: tracking movement of a position of the patient relative to a patient support; and adjusting settings of a component of the radiation image recording system taking into account the tracked movement so that a position of the component relative to the position of the patient remains the same.

34. The method according to claim 20, further comprising: preventing radiation generation when two or more persons are detected in a given area.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0081] The invention will now be described in detail for the particular situation in which the position of the radiation source is set and in which a region of interest is determined by means of an x-ray collimator and occasionally changed by applying the method of the present invention.

[0082] When an X-ray image of a body part of a patient is to be taken, the patient is positioned with the aid of an operator in a suitable position for x-ray image recording. Depending on the type of examination the patient is positioned on a so-called wall stand in a vertical position or alternatively he is positioned on a supporting table in a horizontal position.

[0083] An intelligent patient analysis is then performed. First the patient is identified. Patient data may be entered in a workstation coupled to the x-ray recording device or they may be retrieved from a radiology information system (RIS).

[0084] Next the patient's weight and length are measured and the patient's body mass index is calculated. From this body mass index the body type of the patient can be derived. In accordance with the patient's body type, the radiation dose adequate for image recording is derived. In addition, the patient's thickness of the specified body part can be derived from the depth measurements from the camera.

[0085] The patient's weight can be measured with a sensor in front of the wallstand or in the support table. The patient's height can be derived from the depth measurements. The height measurements can be done directly or indirectly based on a skeletonization of the depth measurements and after identification of the patient.

[0086] In one embodiment patient data (such as name, photo of patient, length, weight, body mass index) are projected onto the wall of the x-ray recording room and/or on an additional monitor or display device attached to the modality or detachable from the modality so that the operator as well as the patient himself can verify the data. In this way errors can be avoided.

[0087] Next, the settings for the x-ray source are determined and set: if the body part of the patient is known and is successfully tracked with the camera, the position of the this body part is mapped from the camera's coordinate system to the coordinate system of the modality and the modality is positioned as best as possible to a position which is optimal for the requested acquisition protocol. In addition the size and position of the collimated area is adjusted based on the size measurements and position of the patient. Additionally, dose acquisition parameters such as kV and mAs can be adapted to fit the patient's fysiology as good as possible. Hereby the thickness of the patient's body part, patient's body type and tissue type of the body part to be irradiated can be taken into account.

[0088] Then the position of the x-ray source including the collimator is to be set or fine-tuned so that x-rays emitted by the source of radiation irradiate the region of interest.

[0089] In this specific embodiment of the invention, the position of the source of radiation relative to the patient as well as the setting of the collimator blades is controlled by means of hand gestures (possibly non-contact: no contact with the patient, nor the recording device) of the operator and tracking of the change of the location of these hands. It is also possible to position the source of radiation and collimated area with standard input as currently is implemented.

[0090] In order to avoid mistakes when tracking the hand movements of the operator, the operator is first to be identified so that only his hand movements and not these of another person that is present in the room (e.g. the patient) are tracked and used for setting of the location of the x-ray source and the collimator.

[0091] For that purpose in this specific embodiment a picture of the operator is taken by means of at least one of the cameras that is provided in the x-ray room. One camera which has a field of view containing the operator and patient is sufficient but also multiple cameras can be used. If the positioning of the cameras is known with respect to each other or with respect to the modality, the information of the multiple cameras can be merged to create a more detailed image or representation of the room.

[0092] Systems such as Microsoft Kinect and Intel RealSense identify and track persons within a video sequence. So once a person has been identified with face recognition, it is therefore possible to track this person with the associated identification label generated by the person tracking software. One could position a depth sensing camera or regular camera facing the entry of the modality room or positioned at a place where the patient and operator are guaranteed to pass. If a frame of such a camera is good enough for face recognition, the person identification from the face recognition is linked with person identification from the person tracking software.

[0093] The operator can be identified by face recognition and person tracking links. Alternatives are possible, for example on the basis of the location where the operator is standing a difference can be made between the operator and the patient (the patient being the person that lies on the supporting table or that stands on the wall stand, the operator being the person in the room that is not on the supporting table or on the wall stand). If even more persons are present in the room, the operator can be identified and tracked as the first person assisting the person on the supporting table or on the wall stand.

[0094] In a specific embodiment the generation of radiation is prevented when 2 or more persons are detected in a given area.

[0095] Once a person is identified as being the operator, movements of a specified body part made by this person are taken into account for controlling the operation of components of the x-ray recording device. The movement of a body part will be measured and the amount of change of movement or an amount which is proportional to the measured amount will be used to control the positioning of the x-ray source as well as to adjust the collimator settings.

[0096] In order not to take into account body part movement, in this case hand movements, which were not intended to be used for controlling one of the above mentioned components, the movement tracking is only initiated once a tracking start indication is generated and detected.

[0097] Likewise the tracking is stopped once a stop tracking indication is given and detected.

[0098] This indication may have different forms. However one of the described embodiments the tracking start indication is a gesture in which each of the hands poses the thumb and index in an angle of approximately 90 degrees while closing the other fingers and the tracking stop indication is releasing the pose of this gesture.

[0099] In order to delineate a region of interest, the operator forms a rectangle with the fingers of both hands above the region of interest for x-ray imaging on the patient.

[0100] In another described embodiment, the tracking start indication is a gesture where both hands are positioned parallel as flat hands in either a vertical or horizontal plane and the tracking stop indication is the closure of one or both of the hands.

[0101] In order to adjust the width of the collimated area, the operator poses his hands parallel vertically. The distance between the start of this gestures defines the current width of the collimator. If the distance between the hands increases, the width of the collimator also increases proportionally. For example, the width is increased proportionally with the ratio between the width of the collimator and the width between the hands at the start indication moment. Another implementation would be to increase the width of the collimator identical to the increase of the distance between both parallel hands.

[0102] In order to adjust the height of the collimated area, a similar method is implemented for hands positioned parallel horizontally.

[0103] A depth camera provided in the x-ray room records the image of the hands and measures the area. This information is applied to the controller of the x-ray source and collimator and the collimator blades are adjusted so that they delineate an opening for x-rays emitted by the x-ray source to pass through which is proportional to the recorded area. The proportional factor can be the ratio between the area of the collimated area at the start tracking area and the area of the indicated area with the hands. Another possibility is that if the width or height of the indicated area increases or decreases with one cm, the corresponding width or height increases or decreases with one cm or a factor thereof.

[0104] From detection of the start tracking signal to detection of the stop tracking signal movements of the hands are recorded and measured by the depth camera and spatial changes of the hand positions (and consequentially of the area delineated by the hands) are applied to the controller of the x-ray source and the collimator. The collimator opening is adjusted in accordance with the detected and measured spatial change of the hand position.

[0105] Once the stop tracking signal is generated and detected, no tracking of the spatial change of the hand positions is performed anymore and no corresponding further changes are applied to the x-ray source and collimator.

[0106] Visual control by the operator can be obtained by displaying the hand movements on the display device of the operator's work station.

[0107] In order to have an additional check of the location of the region of interest on which x-rays will be projected, visible light is projected from the collimator position onto the patient, said visible light delimiting the region of interest.

[0108] As an alternative, the collimated area can be computed by taking into account the position of the 3D camera, the position of the X-ray source and the measured depth data. The estimated collimation area computed based on the known geometry, can be presented as an overlay on a (color) image from another camera or a (color) image from the visual camera in the same 3D camera system.

[0109] Once the position of the x-ray source and the collimation area are set to the satisfaction of the operator, a radiation image of the patient can be taken.

[0110] It is also possible to track the movement of the patient after the x-ray source and collimation area are set correctly. For example, depth measurement data of the collimation area can be taken after the final adjustment of the operator. This depth data can be registered with newly obtained depth measurements. If the registration differs from the initial position, the system can update the X-ray source and collimation area such that the original object of interest is imaged in the same manner. If this is not possible, a warning to the operator can be generated.

[0111] In addition, it is also possible that the modality checks if all acquisition parameters are set correctly. For example, based on the depth measurements and the location of the X-ray source, the system can compute if all active AEC chambers are covered by the patient. If this is not the case, the uncovered AEC chambers can be de-activated or a warning to the operator can be generated, e.g. by display.

[0112] In one embodiment a current position of items in an x-ray room is recorded and movement of parts in the radiology room, e.g. the x-ray source is controlled taking into account the recorded position so as to avoid collision with said items in the radiology room.

[0113] In another embodiment movement of a patient relative to a patient supporting device is tracked and settings, e.g. of an x-ray collimator are adapted taking into account said movement so that the collimation area retains the same relative location to the patient.

[0114] In still another embodiment the generation of radiation is prevented when 2 or more persons are detected in a given area.