U.S. patent application number 12/900808 was filed with the patent office on 2011-03-10 for automatic control of a medical device.
This patent application is currently assigned to KONINKLIJKE PHILIPS ELECTRONICS N.V.. Invention is credited to Silvio BONFIGLIO, Manuel FERNANDEZ, Joost KRAMER, Franco MARTEGANI.
Application Number | 20110060423 12/900808 |
Document ID | / |
Family ID | 36916836 |
Filed Date | 2011-03-10 |
United States Patent
Application |
20110060423 |
Kind Code |
A1 |
BONFIGLIO; Silvio ; et
al. |
March 10, 2011 |
AUTOMATIC CONTROL OF A MEDICAL DEVICE
Abstract
System and method for automatic control of processes or
application, such as the activation or deactivation of a radiation
source for medical purposes. The system comprises an operator
tracking system arranged to determine the gesture/posture of a
user, an evaluation device arranged to evaluate the determined
gesture/posture, and an enabling device arranged to enable and
disable the radiation source in response to an output of the
evaluation device. The operator tracking system may use a gazing
direction analysis that may be based on the output of an eye
tracking system, or an emitter-receiver arrangement for a directed
signal.
Inventors: |
BONFIGLIO; Silvio; (SARONNO,
IT) ; KRAMER; Joost; (EINDHOVEN, NL) ;
MARTEGANI; Franco; (MOZZATE, IT) ; FERNANDEZ;
Manuel; (MALAGA, ES) |
Assignee: |
KONINKLIJKE PHILIPS ELECTRONICS
N.V.
EINDHOVEN
NL
|
Family ID: |
36916836 |
Appl. No.: |
12/900808 |
Filed: |
October 8, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11815866 |
Aug 9, 2007 |
7835498 |
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PCT/IB2006/050535 |
Feb 17, 2006 |
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12900808 |
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Current U.S.
Class: |
700/11 |
Current CPC
Class: |
G06F 19/00 20130101;
A61B 6/469 20130101; A61B 6/00 20130101; G16H 40/63 20180101; A61B
2017/00216 20130101; A61B 90/30 20160201; A61B 6/467 20130101 |
Class at
Publication: |
700/11 |
International
Class: |
G05B 11/01 20060101
G05B011/01 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 18, 2005 |
ES |
P200500366 |
Feb 18, 2005 |
ES |
P200500367 |
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
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10. (canceled)
11. (canceled)
12. (canceled)
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17. (canceled)
18. (canceled)
19. (canceled)
20. (canceled)
21. (canceled)
22. (canceled)
23. (canceled)
24. System for automatic control by gazing, of processes or
applications which require visual attention or monitoring, the said
processes or applications being of the type which require
activation or control of certain elements or stages by means of an
electric control unit, only when monitoring is being carried out;
characterised in that it comprises an emitter for a directed signal
of a suitable nature which is designed to be picked up by a
suitable receiver, when the head of the observer of the system is
positioned such that his eyes face a point of reference, the
receiver of the said signal being associated with control
electronics which form part of the electric control unit which
controls the activation or deactivation of the application or
process.
25. (canceled)
26. (canceled)
27. (canceled)
28. (canceled)
29. (canceled)
30. System according to claim 24, characterised in that, in a
variant embodiment of the invention, the emitter is fastened to the
head of the observer, and the receiver is situated in a fixed
location.
31. System according to claim 24, characterised in that, in a
variant embodiment of the invention, the receiver is fastened to
the head of the observer, whereas the emitter is situated in a
fixed location.
32. System according to claim 24, characterised in that, in a
variant embodiment of the invention, both the emitter and the
receiver are fastened to the head of the observer, whereas an
element which reflects the signal is situated in a fixed
location.
33. System according to claim 24, characterised in that, in an
embodiment of the invention, both the emitter and the receiver are
situated in fixed locations, whereas at least one element which
reflects the signal is fastened to the head of the observer.
34. System according to claim 30, characterised in that the
emitter, receiver or reflective element is secured to the head of
the observer by being integrated in goggles.
35. System according to claim 30, characterised in that the
emitter, receiver or reflective element is secured to the head of
the observer by being integrated in an adjustable band to be
fastened to the face or forehead of the observer.
36. System according to claim 24, characterised in that the signal
can optionally be provided with coding in order to distinguish it
in an environment where there are signals of a similar nature,
corresponding to implementation in the receiver and/or control
electronics of the possibility of identifying the said coded
signal.
37. System according to claim 24, characterised in that the
receiver can optionally be provided with a filter in order to
distinguish other signals with a different wave length from that of
the signal emitted by the emitter.
38. Method for automatic control by gazing of processes or
applications which require visual attention or monitoring, only
when monitoring is being carried out; the method characterised in
that it comprises the steps: Emitting a directed signal of a
suitable nature from an emitter; Picking up the directed signal by
a suitable receiver; Determining the orientation of the head of the
observer of the system; Determining, whether the observer's eyes
face a point of reference; Driving control electronics which form
part of an electric control unit which is associated with the
receiver and which controls the activation or deactivation of the
application or process.
39. (canceled)
40. (canceled)
41. (canceled)
42. (canceled)
43. (canceled)
44. (canceled)
45. (canceled)
46. (canceled)
47. (canceled)
48. (canceled)
49. (canceled)
50. (canceled)
51. A system for controlling one or more functions of one or more
medical devices, the system comprising a control device arranged to
control the function of the medical device, the control device
comprising a first element attached to the head of the operator
that emits a directed signal based on the position of the head of
the operator and a second element positioned in a fixed location
that is capable of receiving the directed signal when the head of
the operator is positioned to emit the directed signal in the
direction of the second element.
52. The system of claim 51, wherein the first element is reflective
material secured to the head of the operator.
53. The system of claim 51, wherein the first element is in goggles
on the head of the operator.
54. The system of claim 51, further comprising a filter on the
second element that permits passage of only the signal of the first
element.
55. The system of claim 51, further comprising the directed signal
being coded to identify the operator and to permit signals by more
than one operator jointly and simultaneously, without interference
between the signals.
56. The system of claim 51, wherein the directed signal is an
infrared or ultrasonic signal.
57. The system of claim 51, wherein the medical device is a
diagnostic or therapeutic device.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a system and method for
automatic activation and deactivation of a radiation source for
medical purposes. The present invention also relates to a system
and method for automatic activation and deactivation of ionising
radiation controlled by the gesture and/or posture of the operator.
Furthermore, the present invention relates to a system and method
for automatic control by gazing of processes or applications which
require visual attention or monitoring.
BACKGROUND
[0002] At present in radiological medical explorations which
involve interventions, for example haemodynamic, vascular,
cardiovascular, digestive, CAT, traumatology or radiotherapy
interventions, etc., in order to activate the ionising radiation
command (for example: x-rays, fluoroscopy, etc) and to see the
image of the patient on the display monitor, it is necessary to
press one or more pedals (or one switch or more switches) which are
habitually located on the floor beneath the operating table, which
in turn may be covered by sheets, plastic, etc., which cover the
patient and the table, thus impeding the view beneath the table.
Consequently, each time the operator raises his foot from the pedal
in order to deactivate the ionising radiation and subsequently
presses down on the pedal again (a process which occurs numerous
times during the course of an intervention), it is necessary for
him to look, or grope with his foot, under the table in order to
locate the pedal which needs to be pressed, since there may be
several pedals with different functions. This therefore wastes time
before the pressing takes place, and also just after the operator
has pressed the pedal, whilst he is turning his head to look at the
monitor, except that in this last case ionising radiation is being
produced.
[0003] Another example which occurs in practice is that during an
intervention the operator looks away (for a few seconds)
repeatedly, without lifting his foot from the pedal.
[0004] On other occasions, the activation pedal is pressed
accidentally, with the consequent generation of radiation which is
not required.
[0005] The sum of all these periods of time wasted before pressing
the pedal prolongs the intervention unnecessarily, and the total of
all the periods after pressing takes place, in which there is a
live image (of x-rays for example), but when the operator is not
looking at the monitor, means that there is an increase to a
greater or lesser extent in the cumulative dose of ionising
radiation received by both the patient and the staff who are in the
exploration room.
[0006] This type of intervention requires continual and repeated
use of ionising radiation, and its complexity may require
implementation of various tasks simultaneously, such as: handling
of complex instruments, the intervention itself on the patient,
monitoring the vital signs, activation of ionising radiation, and
observation of the images obtained on the display monitor, as well
as the concentration required for any intervention work. Because of
the aforementioned complexity of the work, good synchronisation of
activation and deactivation of the ionising radiation is not
obtained, which on some occasions gives rise to lack of
deactivation of the said ionising radiation when the operator looks
away from the display monitor in order to keep intervening on the
patient. This means that the ionising radiation is kept active for
an undesired period of time, thus increasing the dose accumulated
by the patient and by all the staff who are in the exploration
room.
[0007] In addition, also occasionally, the ionising radiation is
activated too soon, without this being noticed.
[0008] Similar problems are caused by radiotherapy treatments:
although in this case it is not necessary, the image provided by
the radiation may also be displayed. However, the purpose of this
therapy is to destroy the tumoral tissues. This therapy is
effective only if the patient is immobile in the position on which
the radiation is focussed, since otherwise all that happens is that
the patient is irradiated unnecessarily. It therefore appears
logical to emit radiation only after the operator has checked on a
monitor that the patient is in the correct position and is not
moving, and whilst he is focussing his attention on the
corresponding controls or indicators which are situated in a
predetermined direction.
[0009] Similarly, outside the medical domain, certain processes or
applications exist, which, as they are carried out, require visual
attention or monitoring, which can be implemented by means of a
monitor, by means of some indicators, or directly.
[0010] For example, there is the simple activity of watching the
television. On many occasions the television set is left switched
on without anyone paying attention to it.
[0011] Another example consists of observing by means of television
with multiple cameras and monitors. If the observer is looking at a
single monitor, the other monitors and their corresponding cameras
are switched on and are consuming energy unnecessarily.
[0012] There are also computer screens which are left switched on
for many hours unnecessarily. Despite having automatic timed
disconnections for energy saving, they lack a system which
activates them simply by the fact of looking at them, thus
requiring manual action on the keyboard or mouse, which is
sometimes a complicated matter, for example if someone is talking
on the telephone and writing at the same time.
[0013] There is also the unnecessary waste of energy, which would
be eliminated by use of the system according to the invention.
[0014] However, it is not only in the context of energy saving with
reference to the connection or disconnection of a monitor that
control by gazing is relevant. Other possible applications also
exist.
[0015] For example, in certain industrial processes it is necessary
to have detailed monitoring on a screen, by means of indicators, or
directly, in order to prevent industrial work (for example welding
or tooling) from being carried out defectively. Thus, this work
should not be allowed to be carried out if this monitoring is not
being carried out by the operator.
[0016] The invention can also be applied to other fields, in order
to activate various processes wherein, because of the complexity of
the work and/or because it is not possible to use one's hands,
various activations or processes can be executed by gazing at one
or more points of reference in order to activate, deactivate and/or
control them.
[0017] Similarly, the control of activations of multiple processes
can be simplified to a single control, and it is possible to select
the activation process required by gazing at the different points
of reference. For example, several barriers to be opened up can be
controlled by a single control unit, since the process would be
selected by the gesture of looking at the corresponding points of
reference or monitors.
[0018] In the above-described examples, control by gazing does not
exist. The system and method according to the invention enhance
existing systems, devices, and methods.
SUMMARY OF THE INVENTION
[0019] The purpose of the system according to one embodiment of the
present invention is to increase the safety and convenience of use
whilst reducing the aforementioned cumulative dose of e.g. ionising
radiation.
[0020] According to the invention, a system for automatic
activation and deactivation of a radiation source for medical
purposes comprises an operator tracking system arranged to
determine the posture and/or gesture of a user, an evaluation
device arranged to evaluate the determined gesture, and a control
device arranged to control the radiation source in response to an
output of the evaluation device.
[0021] A related method for automatic activating and deactivating
of a radiation source for medical purposes comprises the steps of
[0022] determining the posture and/or gesture of a user; [0023]
evaluating the determined posture and/or gesture; and [0024]
controlling the radiation source in response to a result of the
step of evaluating.
[0025] A radiation source that may be activated or deactivated
emits a certain amount of radiation while it is activated. While
the radiation source is deactivated, the amount of radiation is
significantly lower. The terms activating, deactivating, and
controlling may also comprise activating a certain mode of
operation of the radiation source, such as the mode of operation
that is used to produce a given amount of radiation. Activation and
deactivation may be achieved by applying and suppressing a supply
voltage to the radiation source. Alternatively, the radiation
source may be covered by a lid or screen. An operator tracking
system determines posture and/or gesture of the operator, for
example which direction the operator is facing, where the operator
is looking, if he is standing upright, arm or hand gestures etc. An
Evaluation device determines, whether the determined posture and/or
gesture of the user coincides with a predetermined gesture and/or
posture signifying a specific function that the operator wants to
execute. For example, the direction the user faces could be used to
determine whether the operator watches an observation region, which
means that the user watches information displayed and/or events
occurring in the observation region. An Enabling device converts
the result determined by the evaluation device to a physical
interaction, such as interrupting the power supply or parts thereof
to the radiation source, or instructing the radiation source to
switch over into a non-emitting or low-emitting mode. To this end,
the enabling device may be operatively connectable or connected to
the evaluation means.
[0026] According to the invention, the system is of the type which
comprises an emitter element for ionising radiation as the
radiation source. The ionising radiation may pass through part of
the anatomy of a patient in order to obtain images for radiology.
The element emits ionising radiation (x-rays, fluoroscopy,
radiotherapy, etc), which can be picked up by an element which is
sensitive to the radiation after it has passed through the anatomy
of the patient, who is interposed between the emitter element and
the said sensitive element, for example on an operating table or
stretcher.
[0027] The system may also comprise a display monitor, whether the
image is picked up by the sensitive element or is an external image
of the patient picked up by a video camera. The emission or cut-off
of the radiation is usually controlled by a switch or pedal
operated by the operator.
[0028] The improvement which an embodiment of the invention
proposes consists of incorporating, as the operator tracking
system, a device for control by gaze detection in the control unit
for activation or emission of the radiation. This device detects
whether the operator, who is usually a doctor, is looking or not at
the monitor which displays the images obtained, or whether he is
looking in another predetermined direction where the controls or
indicators which require his attention during the irradiation are
located. If this is the case, it permits or directly gives rise to
the emission of the radiation, and optionally cuts it off or
inhibits it otherwise.
[0029] Associated with this device and with the pedal or switch
there may be also implemented an operating mode selector, since,
depending on the interventions concerned, it may be contemplated to
have combined functioning of the control by looking and using the
pedal or switch, or control independently by means of one or the
other. In addition, the device also optionally incorporates
acoustic and/or optical indicators which permit or assist the
precision and calibration of the device for control by viewing, and
detection of whether emissions of radiation are being produced, if
the operator is not looking at the monitor or the corresponding
indicators and controls.
[0030] This therefore addresses the following issues: [0031]
Reduction of the dose of ionising radiation received by the patient
and by the remainder of the staff who are in the exploration room,
as a result of improved control of the method for activation of the
ionising radiation. [0032] Impossibility of the occurrence of
premature activation of the ionising radiation, before the monitor
is observed or before the operator is looking in the predetermined
direction where the controls and indicators are located. [0033]
Inhibition of emissions of radiation by the pedal being pressed
accidentally, as well as of subsequent accidental activation of
other synchronised devices. By way of example, one of these devices
can be a contrast injector pump. [0034] Increase in the handling
comfort in the process of repetitive activation-deactivation, which
takes place during medical radiological intervention explorations.
[0035] Improved precision, since it is not necessary for the
operator to keeping pressing his foot down on the activation pedal
and raising it continually, because these repetitive actions make
the operator change his position on the floor, and this involves a
slight imbalance which is reflected in reduction of the precision
in the process of these interventions. [0036] Increased safety in
activation of the process, since in addition to the original
activation system itself, there is the condition of observation of
this process, which is implicit in the system which is the subject
of the present invention, for activation-deactivation by means of
the gaze of the operator.
[0037] In an embodiment, the operator tracking system (such as a
device for control by gaze detection) takes the form of a detector
of the silhouette of the operator which is based on detectors of
position or movement, and of processing by software. Silhouette
detection is a robust method for deriving the gazing direction of a
user. Even under poor lighting conditions and with the user wearing
glasses or contact lenses, silhouette detection provides reliable
results. The accuracy of silhouette detection can be improved by
carrying out a calibration prior to using it.
[0038] The position and/or movement detectors may consist of one or
more video cameras, whereas the software processes by seeking in
the images obtained the position of a point of reference which is
usually situated in the space between the eyebrows of the operator,
or identification of the symmetry of his silhouette. For example,
the one or more video cameras act as silhouette tracking system,
while the software acts as the evaluation means.
[0039] The device for control by gaze detection may take the form
of an element which emits a directed signal which is received by an
element to receive the signal when the head of the operator doctor
is positioned such that he is looking in the predetermined
direction. The underlying principle may be understood like that of
a beacon. At least one of the emitting element and/or the receiving
element has a relatively narrow lobe. The opening angle of the lobe
defines the accuracy of the gaze detection.
[0040] The emitter element may be attached to the head of the
operator, whereas the receiver element is positioned in a fixed
location. The receiver element detects, when it receives a signal
from the transmitter, indicating that the user is looking in the
direction of the receiver element. The receiver element issues a
corresponding signal. The receiver element being positioned in a
fixed location, the signal issued by the receiver element can be
transferred to a downstream processing unit without the need for
wireless transmission techniques.
[0041] Both the emitter element and the receiver may be positioned
in locations such that the directed signal emitted by the emitter
is detected by the detector when it is reflected on one or more
portions of reflective material secured to the head of the
operator, when he positions his head such that he is looking in the
predetermined direction. In order for the reflection to correspond
to the gazing direction, the reflective material is fixed in a
certain manner. In particular, it is taken care of that the
perpendicular of the reflective material (e.g. a mirror) is
substantially parallel to the gazing direction of the user. This
may be achieved by using a fixation for fixing the reflective
material to the head of the user which can be mounted in a single
manner, thus ensuring the proper orientation of the reflective
material. For example, the nose of the user may be used as a point
of reference for defining the gazing direction.
[0042] According to another embodiment, the emitter element,
receiver, or reflector attached to the head of the operator, is
implanted in goggles. Due to the direct relation between the gaze
direction and goggles, the emitter element, receiver, or reflector
assume a well defined orientation with respect to the eyes of the
user and accordingly his primordial gazing direction.
[0043] The emitter element, receiver, or reflector attached to the
head of the operator, may be disposed on an adjustable support on
the face or forehead of the operator. This arrangement offers
increased flexibility for the fine tuning of the gaze
detection.
[0044] There are as many detector and/or emitter elements as
necessary, which are for example directed such as to cover all the
positions of work of the operator doctor. This assures a large
field of view of the gaze detection system.
[0045] The receiver of the directed signal may include a signal
which permits passage only of the signal obtained from the emitter.
This filters out any other signals so that the reliability
transmission is improved.
[0046] The operating mode selector may comprise at least four
operating modes, i.e. one of maximum safety which requires pressing
of the pedal or button and directing of the gaze in the direction
predetermined for the emission of radiation; another, fully
automatic mode which requires only directing of the gaze in the
direction predetermined for the emission of radiation; another,
deactivation mode which requires only pressing of the button or
pedal for the emission of radiation; and another mode according to
which the gaze in the predetermined direction activates the
emission of radiation, which continues until it is disconnected by
means of the pedal or switch, or automatically if the gaze does not
return to the predetermined direction at regular intervals
established. This offers a high degree of flexibility to the user.
According to his preferences or needs, the user may set the
operating mode.
[0047] The operating mode selector may be used manually so that the
user may use it in an accustomed manner.
[0048] The operating mode selector may be operated by means of
combinations of pressing operations carried out on the pedal. If
the user cannot use his hands during an interventional procedure or
surgery, he may nevertheless switch the system to another operating
mode using his feet.
[0049] The mode selector may comprise certain acoustic and/or
optical indicators which are associated with certain operating
modes which are used for spatial orientation and/or calibration, in
one of which the indicators are made to function when the operator
is looking in the predetermined direction, and in the other of
which the indicators function when radiation is emitted without the
operator looking in the predetermined direction. This functionality
offers valuable feedback about the operation of the radiation
source to the user. It may assist the user in reducing the
radiation dose as much as possible.
[0050] The system controls indirectly other devices which are
synchronised with the emission of the radiation, such as a contrast
injector, lighting of the room, control of the video, and display
of images, etc. This avoids unnecessary operation of periphery. In
the case of contrast agent or the like, the dose administered to
the patient is reduced.
[0051] The device for control by gaze detection optionally includes
an adjustable timer to delay the disconnection of the radiation
emitter element when the operator looks away from the predetermined
direction. This prevents the system from switching on and off too
quickly.
[0052] The signal which is emitted by the signal emitter
incorporates coding which can be identified by the rest of the
system, in order to distinguish it from others, and to permit work
by various (doctor) operators jointly and simultaneously in
different activations, without interference between them. This also
helps to block out disturbing signals.
[0053] The system can additionally be implemented for the voice
command system. The voice command system may take the place of e.g.
the pedal. The doctor may speak certain commands and the system
responds to those commands by switching to another operating mode,
for example.
[0054] The directed signal is of an infrared nature Infrared light
being not visible, it will not disturb the user in his task.
Furthermore, infrared light can be bundled to a narrow lobe, which
defines the accuracy that can be achieved.
[0055] The directed signal is of an ultrasonic nature. Ultrasonic
sound being not audible, it will not disturb the user in performing
his task. Furthermore, ultrasonic sound waves can be bundled to a
narrow lobe, which defines the accuracy that can be achieved.
[0056] According to another embodiment, the system according to the
invention acts in an optimum manner in order to carry out automatic
control of any process or application which involves an electric
control unit, and or which requires visual attention or
supervision.
[0057] The control which is carried out by the system consists of
switching (connection or disconnection by means of the electric
control unit) of the process or application when there is detection
of the gesture carried out by the observer when he looks at a point
of reference, i.e. when he positions his head such that his gaze
faces this point, or when he does not look at this point. This
point of reference can be for example a monitor, which physically
displays the part of the process to be monitored, some indicators
which show the value of some parameters to be monitored, or the
location where the process is taking place.
[0058] For this purpose, the invention comprises the implementation
of an emitter of a directed signal of a suitable nature, for
example an infrared or ultrasonic signal, which is designed to be
picked up by an appropriate detector, i.e. of the same nature as
the emitter. If considered appropriate, and especially in
surroundings where there may be other signals with a similar
nature, the signal can include particular coding which
differentiates it from the other signals.
[0059] For a similar purpose, a method for automatic control by
gazing of processes or applications which require visual attention
or monitoring, only when monitoring is being carried out, comprises
the steps: [0060] Emitting a directed signal of a suitable nature
from an emitter; [0061] Picking up the directed signal by a
suitable receiver; [0062] Determining the orientation of the head
of the observer of the system; [0063] Determining, whether the
observer's eyes face a point of reference;
[0064] Driving control electronics which form part of an electric
control unit which is associated with the receiver and which
controls the activation or deactivation of the application or
process.
[0065] The spatial arrangement of the emitter and receiver will be
such that the signal will be received by the receiver only when the
head of the observer is facing the point of reference, such that,
by means of associated electronics which act as an electric control
unit for the process or application, the latter will be activated
in this case. Similarly, if the head of the observer is not facing
the point of reference, the process will be paused or
deactivated.
[0066] Since the head is the part of the anatomy of which the
orientation is to be detected, there must be secured to the head
one of the aforementioned elements, i.e. the emitter or receiver,
or an element which can reflect the signal to the receiver.
[0067] The point of reference is located in a monitor which
displays the process. Accordingly, the user automatically validates
a command for activating the function only, if he is looking at the
monitor. It should be noted that the point of reference does not
have to coincide with the emitter, receiver or reflective element.
The system can be calibrated so that e.g. the emitter is situated
on top of the monitor, while the point of reference is situated in
the middle of the screen of the monitor.
[0068] The point of reference is located in some indicators which
show parameters of the process. Accordingly, the user automatically
validates a command for activating the function only, if he is
looking at the indicators.
[0069] The point of reference is situated directly in the location
of the process. Accordingly, the user automatically validates a
command for activating the function only, if he is looking at the
process.
[0070] The directed signal is of an infrared nature Infrared light
being not visible, it will not disturb the user in his task.
Furthermore, infrared light can be bundled to a narrow lobe, which
defines the accuracy that can be achieved.
[0071] The directed signal is of an ultrasonic nature. Ultrasonic
sound being not audible, it will not disturb the user in performing
his task. Furthermore, ultrasonic sound can be bundled to a narrow
lobe, which defines the accuracy that can be achieved.
[0072] In a variant embodiment of the invention, the emitter is
fastened to the head of the observer, and the receiver is situated
in a fixed location. Accordingly, the receiver can be connected to
further processing means, such as an evaluator for the gaze
direction.
[0073] In a variant embodiment of the invention, the receiver is
fastened to the head of the observer, whereas the emitter is
situated in a fixed location. In this case, the receiver, e.g. via
a radio link or an infrared link, sends a signal back to the
receiver, which forwards it to further processing means, such as an
evaluator for the gaze direction.
[0074] Alternatively, both the emitter and the receiver are
fastened to the head of the observer, whereas an element which
reflects the signal is situated in a fixed location.
[0075] Another alternative is that both the emitter and the
receiver are situated in fixed locations, whereas at least one
element which reflects the signal is fastened to the head of the
observer. Having both, emitter and receiver in fixed locations
allows that they may be connected by means of cables or the like.
Neither emitter nor receiver needs to be battery powered. The
reflective element is comfortable to wear, because it is light
weight and does not heat up during use.
[0076] According to another embodiment, the emitter element,
receiver, or reflector attached to the head of the operator, is
implanted in goggles. Due to the direct relation between the gaze
direction and goggles, the emitter element, receiver, or reflector
assume a well defined orientation with respect to the eyes of the
user and accordingly his gaze.
[0077] The emitter element, receiver, or reflector attached to the
head of the operator, may be disposed on an adjustable support on
the face or forehead of the operator. This arrangement offers
increased flexibility for the fine tuning of the gaze
detection.
[0078] The signal can optionally be provided with coding in order
to distinguish it in an environment where there are signals of a
similar nature, corresponding to implementation in the receiver
and/or control electronics of the possibility of identifying the
said coded signal. This helps to block out disturbing signals.
[0079] The receiver can optionally be provided with a filter in
order to distinguish other signals with a different wave length
from that of the signal emitter by the emitter. This helps to block
out disturbing signals.
[0080] According to another embodiment of the invention, a system
for automatic controlling at least one function of at least one
medical device is proposed. The system comprises an operator
tracking system arranged to determine the posture of an operator of
the medical device, an evaluation device arranged to determine
whether the determined posture indicates that the operator exploits
said function of said medical device, and an control device
arranged to control the function of the medical device.
[0081] According to a related embodiment, a method for automatic
control of at least one function of at least one medical device
comprises the steps of: [0082] Determining by means of an operator
tracking system the posture of an operator of the medical device;
[0083] Determining by means of an evaluation device, whether the
determined posture indicates that the operator exploits said
function of said medical device; and [0084] Controlling said
function of the medical device by means of a control device.
[0085] A function of a medical device may be switching on or off,
activating, deactivating, enabling, disabling the medical device as
a whole or only partially. A function of the medical device may
also be understood as a changing the mode of operation of the
medical device or of parameters thereof. Control of a function of a
medical device comprises causing the function to be executed.
Exploitation of such a function of the medical device comprises the
operator requesting the function or appreciating the result of the
function, such as looking at data or information provided by the
function. The ascertainment of the exploitation of a function may
not always be possible with absolute accuracy. In these cases, a
certain calculated confidence about the operator exploiting the
function may be used. Among others, the posture of the operator may
comprise where the operator is standing, which direction his body
or certain body parts are aiming at, flexion of his body and/or
joints, and the like. The control device converts the result of the
evaluation device which indicates whether the operator exploits the
function. This also comprises those cases, in which the operator
requests the execution of a function. A unique gesture may be
defined as a command for a certain function. In a plurality of
predefined gestures, each gesture corresponds to a certain function
(note that multiple assignments are also possible, i.e. there are
several gestures for one function, for example one for right-handed
people, another for left-handed people). If the operator performs a
gesture that the evaluation device recognizes as a gesture
associated with a function (e.g. "right hand with palm facing
upward moves up approx. 10 cm"), then it tries to execute that
function (e.g. "increase zoom of displayed image") by instructing
the control device accordingly.
[0086] The evaluation device may be further arranged to determine
whether the posture of the operator indicates that the operator
observes a predetermined observation region. This may be achieved
by evaluating for example the head position and orientation. The
position and orientation of the head provides a good estimation of
the actual gazing direction of the user.
[0087] The medical device may be a diagnostic device using x-rays
to provide live video images which are then displayed on the screen
of a monitor. Instead of x-rays, other types of radiation or waves
may be contemplated, such as ultrasound, laser, electromagnetic
waves in general, or the like. The invention may be used for
example in the following modalities: magnetic resonance, nuclear
magnetic resonance, computer tomography, positron emission
tomography, echocardiography, angiography, etc. The medical device
may also be a therapeutic device. The mentioned function of the
medical device may be the power supply to a particular element of
the medical device, but is not restricted thereto. For example, it
may be contemplated to control the intensity, wavelength of
radiation that is emitted by a radiation source of the medical
device. This feature may be used, if the operator wishes a more
detailed view of a certain anatomy. The operator tracking system
may evaluate the position and orientation of the face, the head,
the upper body, or the entire body of the operator.
[0088] In a related embodiment, the evaluation device is further
arranged to determine whether the posture of the operator indicates
that the operator observes a predetermined observation region. This
may be achieved by determining whether the operator is facing the
observation region, for example by analyzing the symmetry of an
image of the operator captured by an appropriate image acquisition
device. It may also be achieved by looking for certain features of
the operator, for example his facial features.
[0089] In a related embodiment, the medical device is a radiation
emitting medical device. By using the invention with a radiation
emitting medical device, the radiation that a patient and/or the
staff are exposed to is reduced. This reduction of radiation
exposure may be achieved e.g. by (partially) interrupting or
diminishing the power supply to a radiation producing element of
the medical device, such as an x-ray tube. In this case the
function that is paused by the system according to the invention is
the power supply function of the radiation producing element. It is
mentioned that a laser emitting medical device (therapeutic or
diagnostic) is a radiation emitting device, as well.
[0090] The observation region may be located in a monitor
displaying data relating to the medical device. Alternatively, the
observation region may be located at the target site of the medical
device. This links the pausing and resuming of the function of the
medical device to the operator watching the monitor or the target
site, respectively. Target site of the medical device means the
site where the medical device interacts with the patient. For a
diagnostic device the target site may be understood as the scanned
volume of the patient, for a therapeutic device it may be the site
of treatment.
[0091] The observation region may comprise a plurality of sub
regions, each sub region being associated with the control of a
specific function of the at least one medical device. This can be
used in procedures, where various functions have to be controlled
(multi-controls procedures). Each control is activated through data
or images located on a given zone of the display's screen. In this
case the probability of activating a wrong control can be minimized
by conditioning the activation to the detection by the eye tracking
system of the specific zone of the screen the operator addresses
with his eyes.
[0092] In an embodiment, the system may further comprise an
operator command input device and a signal combination device
arranged to combine the respective output signals of the evaluation
means and the operator command input device. Accordingly, the
operator may command the function of the medical device to some
extent. In particular, the operator may activate the function by
means of the operator command input device when he is about to
perform the critical step(s) of the intervention, for which live
x-ray video support is required (long term activation of the
function). However, the operator does not need to deactivate or
pause the function (e.g. x-ray emission) while performing the
critical step(s). The fact whether the operator is watching the
observation region is determined by the eye tracking system and the
evaluation means. If it is determined that the operator is not
watching, the input to the signal combination device relating to
the evaluation means assumes a value that causes the signal
combination device to generate a signal which in turn causes the
enabling means to pause or disable the function of the medical
device. As such, the eye tracking system and its downstream
components act as an override for the function of the medical
device. This override assures that the function of the medical
device is activated or resumed only, if the operator is watching
the observation region.
[0093] The operator tracking system may be or comprise an eye
tracking system. Using an eye tracking system, the user does not
have to wear equipment for example on his head. The eye tracking
system is capable of determining the true gazing direction, instead
of merely the direction of the head, which may be different from
the true gazing direction, if the eyes of the operator are inclined
with respect to their normal orientation. The determination of the
gazing direction may be a simple decision whether the operator is
looking in a particular direction, i.e. a yes/no decision. However,
a more precise determination of the gazing direction may also be
employed. The eye tracking system may also detect the state of the
eye lids, i.e. whether these are open or closed. The above
mentioned predetermined observation region is a region where the
operator observes an intervention either directly or indirectly by
means of an appropriate medical device modality. The observation
region may be affected by the medical device, be it that it shows a
live video or that it is exposed to radiation or the like. A
purpose of the evaluation device is to provide a decision about
whether the operator is looking at the observation region.
[0094] The eye tracking system may be chosen from a group
comprising coil systems, Dual Purkinje systems, Corneal reflection
systems, pupil boundary systems, and video based systems. Nowadays,
several technologies are available for eye tracking. Some of these
technologies excel in spatial/temporal accuracy, while others may
be more easier to use or less expensive. As an example, for a
single-control application where the eye tracking system simply has
to detect if the operator is looking at the screen of the display,
a video-based system using a CCD camera with visible light could
represent a suitable solution. In this case, the main requirements
for the eye tracker are the field of view, the viewing distance,
face recognition, rather than position accuracy. Better accuracy is
requested in multi-control applications where the eye tracking
system has to identify the specific zone of the screen observed by
the user. An infrared-based eye tracking system could be employed
in this case. In both cases, a large field of view of the camera
allows a certain level of freedom in the movement of the operator.
Moreover, the solution has to guarantee the correct operation under
different environmental and usage situations (different light
conditions, different layouts, different positions of the operator,
tolerance for glasses and contact lenses . . . ).
[0095] According to a further embodiment of the present invention a
medical device comprises a system as described above. The medical
device may further comprise a radiation source and a radiation
detector. The medical device may further comprise a display for
images acquired by means of the medical device.
[0096] A medical device that comprises a system as described above
may provide easy manipulation. The medical device makes it possible
to implement control features assisting the operator, for example a
surgeon, in his interventional procedure by automating one or
several functions that are usually controlled by the operator. If
the medical device comprises a radiation source and a radiation
detector, it is possible to reduce the cumulative amount of
radiation the patient is exposed to. A display for images acquired
by means of the medical device may also define an observation
region the operator needs to watch if he wishes a certain function
to be performed by the medical device. Accordingly, the operator
must acknowledge by looking the execution of this function.
BRIEF DESCRIPTION OF THE DRAWINGS
[0097] In order to complete the description which is being
provided, and for the purpose of assisting better understanding of
the characteristics of the invention, the present description is
accompanied, as an integral part of it, by a set of drawings in
which the following is represented on an illustrative and
non-limiting basis:
[0098] FIG. 1 is a schematic view of the system which is the
subject of the present invention.
[0099] FIG. 2 shows various possible embodiments of the device for
control by gaze detection.
[0100] FIG. 3 shows a variant of the embodiment shown in FIG. 1, in
which recognition of the silhouette of the operator is used.
[0101] FIG. 4 shows schematically another embodiment of the system
according to the invention.
[0102] FIG. 5 shows a series of variants of implementation of
detection of the signal which is directed and emitted by the
receiver, and of recording of the signal by the detector, according
to the invention.
[0103] FIG. 6 shows two variant embodiments of attachment to the
head of the user, of the emitter, detector or reflector.
[0104] FIG. 7 is a schematic view of the system which is the
subject of another embodiment of the present invention.
[0105] FIG. 8 is a block diagram of the system shown in FIG. 7.
[0106] FIG. 9 shows the screen of a monitor in a related
embodiment.
[0107] FIG. 10 shows a partial block diagram of a system that makes
use of the monitor screen of FIG. 9.
DESCRIPTION OF PRACTICAL EMBODIMENTS OF THE INVENTION
[0108] The system 1 according to the present invention consists of
an element 2 which emits ionising radiation, for example x-rays,
fluoroscopy or the like.
[0109] The emission of radiation by this element 2 is habitually
controlled by an emission control unit which includes a pedal 3 or
switch which is pressed by the operator. For as long as the pedal
is pressed down, the emission of radiation takes place, and vice
versa.
[0110] In the case of obtaining radiological images, the beam of
radiation is directed towards the patient 4, who is usually lying
on a stretcher 5, and subsequently meets an element 6 which is
sensitive to this radiation. When the beam passes through the body
of the patient, the absorption which occurs leads to formation of
the image which is picked up by the element 6, and is transferred
to the display monitor 7.
[0111] In the case of radiotherapy, the image which is shown on the
screen serves the purpose only of verifying that the patient is
positioned correctly, and has not moved. For this purpose, the
image may be the one picked up by the element 6, or an image taken
by a video camera. In this case, in addition, it may be
contemplated for the gaze control unit to be focussed on the
attention by means of various controls or indicators of the
monitor, once the correct positioning of the patient has been
checked.
[0112] The invention proposes to interpose in the emission control
a device for control by gaze detection, which permits the emission
of radiation only if it detects that the operator is looking at the
monitor, or is focussing his attention in the predetermined
direction where the controls and indicators which are needed in the
case of radiotherapy are located.
[0113] In order to make the system versatile, the emission control
unit includes an operating mode selector 8, which is controlled
manually as can be seen in FIG. 1, or is controlled by combinations
of operations of pressing the pedal. This selector can take into
account at least the following modes: [0114] Default, maximum
safety mode, in which the ionising radiation is activated only when
two circumstances exist simultaneously, i.e. that the operator has
pressed the original activation pedal, and is looking in the
predetermined direction (at the monitor or at the controls and
indicators). [0115] Safety mode applied at the beginning of
activation, when the operator looks in the predetermined direction
in order to activate the emission of ionising radiation, which will
then continue to be applied even if he does not look in that
direction, with deactivation being produced by means of the pedal
or switch, or automatically if a specific interval of time elapses
without the operator looking in the predetermined direction. [0116]
Fully automatic mode, in which activation occurs directly when the
operator looks in the predetermined direction, without needing to
press the activation pedal. Deactivation takes place automatically
when he looks away from this direction. [0117] Switched
off-deactivated mode, in which the system proposed does not
interfere with the normal functioning of the equipment, and
consequently, in order to produce ionising radiation, only the
pedal-switch is pressed. [0118] Other modes are also possible,
which can be a combination of those previously described.
[0119] It is also possible to introduce a programmable timer 9,
which goes from zero to the value which is considered necessary
(for example tenths of a second), in order to avoid the problems
which would be caused by disconnection or interruption of the
emission of radiation as a result of rapid and/or involuntary
movements which presuppose that the operator is not looking at the
monitor.
[0120] Since it is assumed that, by using ergonomic criteria, the
simple natural gesture of the operator turning his head in the
predetermined direction will activate the radiation automatically,
and that in the opposite case the radiation will be disconnected,
the device for control by gaze detection can be implemented by any
means which achieve this purpose.
[0121] By way of non-limiting example of the invention, for this
device use is proposed of a unit for control or detection of the
silhouette of the operator 10 by means of detectors for position
and/or movement and by means of processing by software. The
position and movement detectors may consist of a video camera 6a,
whereas the software would monitor a reference point, for example
the space between the eyebrows of the operator, or the symmetry of
his silhouette, in the images obtained. It may also be contemplated
to have the system observe the other body parts of the operator,
such as the hands, or the entire body. When the processing
identifies that the operator is looking in the predetermined
direction (at the monitor or at the controls and indicators), this
will give rise to emission of the ionising radiation.
[0122] Another, simpler embodiment could consist of implementing
the device by means of an element 11 which emits a directed
ultrasound or infrared signal, and a receiver 12 for this signal.
The positioning of these elements will be such that the signal
emitted by 11 will reach the receiver 12 only when the operator is
looking at the monitor or in the appropriate direction. For this
purpose, the emitter can be located in the monitor, and the
operator can wear the receiver, or vice versa. Also, for example,
the emitter and receiver can be located in the monitor, or they can
be worn by the operator, and use can be made of a reflector 15
which reflects the signal emitted and to be picked up. The most
rational solution may be that shown in FIGS. 1 and 2.3, in which
the emitter and receiver are placed in any suitable location, such
as in the monitor, whereas the operator wears a reflector 15, for
example in his goggles 13, which may or may not be leaded, or on a
support 14 which is adjustable to the head, occupying the surface
area necessary, and reflecting the signal which is emitted to the
detector when the operator turns his head towards the monitor.
[0123] The detectors for position and/or movement could also be
based on another principle, such as a position sensing system
having one or more emitters attached to the user and a plurality of
receivers. In this case, the signal need not be a directed signal.
The determination of the position is achieved by measuring the time
delay between signals received at the different receivers. By using
two or more emitters, each emitting a characteristic signal, even
the orientation (i.e. among others the gazing direction) of the
operator may be determined, if the two emitters are attached to
different parts of the body of the operator, i.e. one of the
emitters is attached to e.g. the forehead and the other is attached
to the back of the head.
[0124] If necessary, the receiver 12 can incorporate a filter, not
shown, which will permit passage only of light with a wave length
which corresponds to that of the infrared emitter, in order to
prevent other emissions with other wave lengths from being able to
interfere in the activation of the system. It would also be
possible to implement in the directed signal coding which
distinguishes it from other signals, and to provide the detector
and/or the system electronics with the capacity to make the
corresponding identification and discrimination.
[0125] As many emitter or receiver elements will be provided as is
necessary to cover all of the area of work of the operator
doctor.
[0126] Since the system controls the emission of the radiation, it
will also control indirectly the functioning of other synchronised
elements, such as the light in the room, video, and display of
images, etc.
[0127] Voice activation commands may also be implemented in the
system, in order to co-operate in the procedure with optimum
convenience and minimum irradiation.
[0128] In FIG. 4, the system 21 according to another embodiment of
the invention comprises an emitter 22 of a signal of a suitable
nature, such as a directed infrared or ultrasonic beam, which is
designed to be received by a suitable receiver 23, only when the
head 24 of the observer of the system is positioned such that his
eyes are directed towards the point of reference, which in this
non-limiting example of the invention consists of a monitor 25
which displays the process, or vital parts of it.
[0129] At such a moment, control electronics 25a for the process or
application 26, associated with the receiver 23, will give rise to
connection or activation of the process 26, whereas if this is not
the case they will give rise to deactivation of the process.
[0130] In order to obtain receipt of the signal emitted by the
emitter 22 at the receiver 23 under these circumstances, the
following implementations are proposed: [0131] Fastening of the
emitter 22 on the head 24 of the observer, and placing of the
receiver in a fixed location, ideally on the monitor 25 itself
(FIG. 5.1). [0132] Fastening of the receiver 23 on the head of the
observer, and placing of the emitter in a fixed location, ideally
on the monitor 25 itself (FIG. 5.2). [0133] Fastening of both the
emitter 22 and the receiver 23 on the head of the observer,
corresponding to the positioning in a fixed location, ideally on
the monitor 25 itself, of an element 27 to reflect the signal
emitted by the emitter, in order for this signal to be received
after being reflected back to the receiver (FIG. 5.3). [0134]
Positioning of both the emitter and receiver in the fixed location,
such as on the monitor 25, corresponding to fastening onto the head
of the observer of an element 27 to reflect the signal (FIG.
5.4).
[0135] With this last configuration there is no need for the
observer to wear certain elements, i.e. emitters or receivers,
which require sources of energy and/or connections, whether these
are wireless or wired, to the control electronics 25a.
[0136] It should be taken into account that the fixed locations
where the emitter, receiver or reflector described in the preceding
cases is located, need not coincide with the fixed point of
reference towards which the gaze is directed. They can be in any
location, provided that the condition is fulfilled that the signal
reaches the receiver only when the head of the observer is
positioned such that his eyes are facing the point of
reference.
[0137] The fastening to the head of the wearer of the elements
(emitter, receiver, reflectors or other emitters of communication
to the control electronics) which are necessary for functioning of
any of the configurations of the system, can take many forms. By
way of non-limiting example, the insertion of these elements is
proposed in goggles 28, or on a support or band 29 which is
adjustable on the head or forehead of the observer, as represented
respectively in FIGS. 6.1 and 6.2.
[0138] It will be appreciated that the positioning of the emitter
22, receiver, and if applicable the reflecting element 26, will be
such that the direct or reflected incidence of the signal on the
receiver will take place only when the head of the user is facing
the screen of the monitor.
[0139] Optionally, if the system is installed in a location where
there are signals of the same nature, the signal of the system can
be provided with coding to identify it or distinguish it from
others, associated with the service of detection of this identity
implemented in the control electronics. Also, or optionally, the
receiver can be provided with a filter, not shown, which
distinguishes signals with different wave lengths.
[0140] Finally, the system can be combined with other systems for
switching or manual or automatic control of the process or
application, thus providing mixed control which will provide
greater security of operation.
[0141] FIG. 7 shows a system according to a embodiment of the
present invention. The system 31 may be used for automatic pausing
one or several functions of a medical device (not shown). System 31
comprises a video camera 36a and an associated image analysis and
evaluation entity 35a, such as a computer running an appropriate
program. The camera 36a is connected to the image analysis entity
35a and mounted on top of a monitor 35. An eye tracking system is a
part of the system according to the embodiment that is currently
described. FIG. 7 schematically shows the eye 41 of an operator.
The eye tracking system may comprise camera 36a and parts of the
image analysis entity 35a. Its purpose is to determine what
direction the operator of the medical device is looking at. This
may also be achieved by evaluating the gesture and/or posture of an
operator. Regarding the underlying technology, this functionality
may be achieved by one of the following technologies: Iris
recognition, silhouette recognition, or IrDA camera with Corner
Cube Reflector. Other technologies for determining the gazing
direction of an operator more or less accurately that do not use a
camera are for example inertial tracking, position sensitive
detector, sensorial EOG (electrooculogram), transmitter/receiver
systems based on infrared or ultrasound, or light guns. The image
analysis and evaluation entity may also comprise means to evaluate
whether the operator looks at a predetermined observation region,
i.e. whether his gazing direction targets the observation region.
This may be necessary, if the observation region is not in the near
vicinity of the camera 36a, since in these cases a straight forward
binary decision as to "operator is looking/is not looking in the
direction of the camera" may not work anymore. Also in those cases,
in which the observation region is subdivided in a plurality of sub
regions (see description of FIGS. 9 and 10 below), the gazing
direction needs to be determined more precisely, for example in
terms of azimuth and elevation angles, or in terms of regions such
as "centre of the screen", "lower left corner of the screen" etc.
In FIG. 7, monitor 35 displays a target 39, which the operator
needs to look at if he wishes to resume the function of the medical
device that is associated with the target. System 31 furthermore
comprises a pedal 33 to be operated by a foot 42 of the operator.
The output port of the pedal is connected to a signal combination
device 38. Another input of the signal combination device 38 is
provided by the output of the image analysis entity 35a. The signal
combination means 38 combines both signals by means of a logical
AND. The output of the signal combination means is valid if both
input signals are valid. Thus, the behaviour is as follows: While
the operator is not looking at the display (corresponding to the
observation region), the eye tracking system does not validate an
unintentional activation of the function of the medical device. For
a cardiovascular interventional procedure, the function may be for
example the fluoroscopy flow or the power supply for the x-ray
tube. While the operator is watching the screen during his
intervention, he activates through pedal 33 the fluoroscopy flow
and the eye tracking system validates the command. The fluoroscopy
flow or the power supply of the x-ray tube will resume for as long
as both input signals to the signal combination means 38 are
valid.
[0142] FIG. 8 shows a block diagram of a part of the eye tracking
system and the medical device. When performing fluoroscopy, the
following conditions must be fulfilled. There is a need for a
fluoroscopy flow, i.e. radiation. The fluoroscopy flow is produced
in a fluoroscopy flow generating element 32a. Besides the
fluoroscopy flow, the image acquisition sub system of the medical
device has to be ready, as well. In FIG. 8, the state of the image
acquisition subsystem is represented by signal 32b. Typically, the
image acquisition sub system may be kept functioning during the
entire duration of the cardiovascular interventional procedure,
since it does not harm the patient and the staff. Furthermore, the
equipment of the image acquisition sub system may not lend itself
to repetitive switching actions due to its response time and
possible damage to the equipment. The fluoroscopy flow on the other
hand is typically harmful to human beings, such that the patient
and the staff should not be exposed to it longer than necessary. In
the case of an x-ray tube, a high voltage is supplied to the tube
in order to create x-rays. Cutting off this high voltage supply
causes the radiation the to cease. In the upper left corner of FIG.
8, a merge point is shown, which indicates that above mentioned
conditions need to be fulfilled in order to obtain an x-ray image.
If they are, then x-ray generation and image acquisition entity 32
generates live video images. The live video images are displayed to
the doctor 40 on monitor 35 (FIG. 7) who makes a judgement based
upon these images. When the doctor 40 is momentarily done looking
at the live video images, he may avert his gaze from the monitor or
lift his foot from the pedal 33. In the first case of the doctor
averting his gaze from the monitor, this is detected by the eye
tracking system and evaluation means 36a, 35a. The evaluation means
35a issues a corresponding signal to the signal combination means
38 indicating that the doctor is not longer watching the live video
images in the monitor. A similar signal is issued by the pedal 33
in case the doctor or operator lifts his foot.
[0143] FIGS. 9 and 10 show the screen of a monitor 33 and the logic
used to process information issued by the eye tracking system,
respectively. The screen shows the observation area of the
automatic pausing system described above. The observation area
comprises three sub regions 49, 59, and 69. This approach can be
used in procedures where various functions have to be controlled
(multi-controls procedures). Each control 43, 53, 63 is activated
depending on the status of a specific parameter which is visualized
through data or images located in a given zone of the display's
screen. In this case the probability of activating a wrong control
can be minimized by conditioning the activation to the detection by
the eye tracking system 36a, 35a of the specific zone of the screen
the operator addresses with his eyes. This conditioning is
performed by signal combination means 48, 59, 69 in a similar
manner as performed by signal combination means 38.
[0144] A freeze image function may also be implemented in the
system. The system may freeze the latest video image displayed if
the operator lifts his foot from the pedal, but continues to watch
the screen of the monitor. Especially in those cases in which the
operator needs to carefully judge the situation before proceeding,
a freeze image function may be useful. The system resumes showing
live video images when the operator presses the pedal again and is
watching the screen.
[0145] Another additional functionality of the eye tracking system
may be the recognition of the operator from a plurality of persons
watching the screen. During cardiovascular interventional
procedures, not only the doctor, but also other medical staff, such
as nurses may be present in the room. The eye tracking system may
consider the gazing direction of the main operator (e.g. the
doctor), only. This may be achieved by teaching the eye tracking
system, who the main operator will be for the following procedure.
During the procedure, face recognition may be used, or the operator
may wear a distinctive mark, such as a patch or pin on his scrub.
It may also be possible to define two or more operators. The system
will then evaluate whether at least one of the operators is
watching and resume, activate, or enable the corresponding function
of the medical device.
[0146] Having described sufficiently the nature of the invention,
and the manner of putting it into practice, it should be noted that
details of the arrangements which are described above and
represented in the attached drawings can be modified, provided that
this does not alter its basic principle.
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