Patient referencing in a medical navigation system using projected light points
Abstract
Procedure for referencing or registering a patient or a patient's body part, in a medical camera-assisted navigation system with the following phases: - the body part of the patient to be referenced is brought to the detection area of a navigation system assisted by at least two cameras (5, 6), which records, assisted by computer, the three-dimensional spatial positions of light markings (3) , -by means of a beam of light (2) from a manual light bulb (1), which is not followed positionally by means of the navigation system, Luminous markings (3) are produced on the surface of the body part to be referenced, whose three-dimensional position is determined by only the existing cameras of the camera-assisted navigation system, - the position data for the luminous markings (3) determines the spatial position of the surface of the body part to be referenced.

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16 claims: 2 independent, 14 dependent
- 1ES 2 180 481 T3 REIVINDICACIONES 1. Procedimiento para el referenciado o registro de un paciente o de una parte corporal de un paciente, en un sistema médico de navegación asistido por cémara con las siguientes fases:- la parte corporal del paciente a referenciar se lleva a la zona de detecciéon de un sistema de navegacioén asistido por al menos dos céamaras (5, 6), el cual registra, asistido por ordenador, las posiciones espaciales tridimensionales de marcaciones luminosas (3), - mediante un rayo de luz (2) de un foco de luz manual (1), que no es seguido posicionalmente por medio del sistema de navegacioén, se producen en la superficie de la parte corporal a referenciar marcaciones luminosas (3) cuya posiciéon tridimensional es determinada por solamente las caémaras existentes del sistema de navegaciéon asistido por caémara, - mediante los datos de posicioén para las marcaciones luminosas (3) se determina la posicioén espacial de la superficie de la parte corporal a referenciar.
- 2Procedimiento seguén la reivindicaciéon 1, en el cual la posiciéon espacial de la superficie se coordina con un conjunto de datos graéficos realizado previamente con un procedimiento de obtenciéon de imagen, en especial con un conjunto de datos de escaneado CT, MRI (tomografla de resonancia magnéetica), PET, SPECT, por rayos X o ultrasonidos, para referenciar los datos graéficos actuales de este conjunto de datos.
- 3Procedimiento seguén una de las reivindicaciones 1 éo2,enelcualelrayodeluzesunrayo de luz no visible, especialmente de luz infrarroja, estando las céamaras (5, 6) ajustadas al registro de reflexiones para esta luz.
- 4Procedimiento seguén la reivindicacioén 3, en el cual el rayo de luz es un rayo de luz léaser.
- 5Procedimiento seguén la reivindicaciéon 3 oé 4, en el cual mediante un segundo rayo de luz visible, en esencia dirigido hacia la misma zona del objetivo, tal como el rayo de luz de referenciado no visible (2), se produce una reflexiéon visible en la superficie.
- 6Procedimiento seguén la reivindicaciéon 5, en el cual el segundo rayo de luz es un rayo léaser visible.
- 7Procedimiento seguén la reivindicaciéon 6 éo 7, en el cual ambos rayos de luz se producen con una uénica fuente luminosa, dos fuentes luminosas una al lado de la otra o una dentro de la otra.
- 8Procedimiento seguén una de las reivindicaciones 1 a 7, en el cual con el rayo de luz de referenciado (2) se producen en la superficie, una tras otra, varias marcaciones luminosas, mientras se registra continuamente la posicioén de las marcaciones luminosas (3) producidas, y concretamente en especial durante el tiempo necesario hasta recoger el nuémero suficiente de datos de posicioén para determinar la posicioén espacial.
- 9Procedimiento seguén una de las reivindicaciones 1 a 8, en el cual la disposiciéon de las céamaras o la parte corporal a referenciar son movidas durante el referenciado de tal forma que se eliminan las sombras de caémara, siendo seguido el movimiento relativo de la parte corporal y de la disposicioén de caémaras mediante una disposiciéon de marcaciones (10) en el sistema de navegacioén dispuesta de forma fija frente a la parte corporal.
- 10Dispositivo para el referenciado o registro de un paciente o de una parte corporal de un paciente con un sistema méedico de navegaciéon asistido por al menos dos céamaras (5, 6), con el cual se pueden registrar, asistido por ordenador, las posiciones espaciales tridimensionales de marcaciones luminosas (3) en una zona de detecciéon, y con un medio para el registro de marcaciones luminosas (3) en la superficie de la parte corporal a referenciar cuya posiciéon espacial tridimensional es determinada por el sistema de navegacioén asistido por caémara, siendo el medio para el registro de marcaciones luminosas (3) un foco de luz manual (1) que produce reflejos de luz en la superficie como marcaciones luminosas, caracterizado porque la posicioén espacial tridimensional de las marcaciones luminosas (3) puede ser determinada por las céamaras existentes del sistema de navegacioén, sin que el foco de luz manual deba ser seguido posicionalmente mediante el sistema de navegaciéon.
- 11Dispositivo seguén la reivindicacioén 10, caracterizado porque el foco de luz manual (1) es un foco de luz no visible, especialmente de luz infrarroja, estando las céamaras (5, 6) ajustadas al registro de reflexiones para esta luz.
- 12Dispositivo seguén la reivindicacioén 11, caracterizado porque el foco de luz manual (1) es un foco de luz laéser.
- 13Dispositivo seguén la reivindicacioén 11 oé 12, caracterizado porque el foco de luz manual (1) irradia un segundo rayo de luz visible, que estéa dirigido esencialmente hacia la misma zona de objetivo tal como el rayo de referenciado no visible, produciéendose adicionalmente una reflexioén luminosa visible en la superficie.
- 14Dispositivo seguén la reivindicaciéon 13, caracterizado porque el segundo foco de luz es un foco para luz laéser visible.
- 15Dispositivo seguén la reivindicacioén 13 oé 14, caracterizado porque las fuentes luminosas para ambos rayos de luz pueden estar unidas en una uénica fuente luminosa, ser dos fuentes luminosa una al lado de la otra o una dentro de la otra.
- 16Dispositivo seguén una de las reivindicaciones 10 a 15, caracterizado porque, ademéas, comprende una disposicioén de marcaciones (10) ES 2 180 481 T3 dispuesta de forma fija frente a la parte corporal, mediante la cual se sigue el movimiento relativo entre la parte corporal a referenciar y la disposicion de cámaras para eliminar las sombras de cámara en el referenciado. NOTA INFORMATIVA:Conforme a la reserva del art. 167.2 del Convenio de Patentes Europeas (CPE) y a la Disposición Transitoria del RD 2424/1986, de 10 de octubre, relativo a la aplicación del Convenio de Patente Europea, las patentes europeas que designen a España y solicitadas antes del 7-10-1992, no producirán ningún efecto en Espana en la medida en que confieran proteccion a productos quámicos y farmaceuticos como tales. Esta informacioán no prejuzga que la patente estáeo no incluáda en la mencionada reserva.
Independent claims16
46 paragraphs in 4 sections, as filed
IS 2 180 481 T3
DESCRIPTION
Referencing a patient in a medical navigation system, using projected light points.
The present invention relates to a method and a device for the referencing or registration of a patient or a body part of a patient in a camera-assisted navigation medical system.
Currently, surgical operations or radiotherapy treatments are carried out more and more with the help of so-called navigation systems or tracking systems. In them, the patient's data, which have been ascertained with an imaging procedure, for example, a computer tomography or magnetic resonance imaging, are used to show the doctor by means of an on-screen emission where the instrument is at all times. treatment. An application case consists, for example, in showing the position of the tip of an instrument inside the body part being treated, in order to be able to operate with great accuracy in the places to be treated.
For such a navigation system to function, the momentary position of the patient or the body part to be treated must be known in situ during the treatment. This current position data can then be coordinated with data from the imaging procedure, for example, with data from a computer tomography obtained at a certain time before treatment. After this coordination, the image-assisted treatment can be started.
According to the current state of the technique, the aforementioned coordination is carried out with the help of markings, that is, with the help of artificial or natural field markers on the patient. Thus, for example, the German patent No. 196 39 615 proposes to adhere artificial markers to the skin of the patient before a tomographic recording, using at the same time such markers that are visible in the tomographic image. After the tomography, the patient is taken to the operating room. At the beginning of the treatment, the referencing of the patient or his body part was carried out, accessing the markers placed in oil with an observable marker in the navigation system, to make his current position known to the assistant computer system. Once the position of the markers is known, the position of all the other points of the group of tomographic data in the current position of the patient can also be obtained, assisted by computer, and the treatment with assisted navigation can be started.
However, the use of such externally applied markers on the surface of the skin has some drawbacks. First of all, the surface of the skin is slightly movable and such displacements provide inaccuracies in referencing. Especially when accessing the markers with the marker, slight displacements of the skin may occur.
Nor can you place so many artificial markers as to compensate for such inaccuracies, as this will unnecessarily lengthen the referencing. Invasive solutions, for example, fixing the markers on the bone substance under the skin, are very unpleasant for patients, whereas natural field markers, such as the nasal root, often cannot be closely referenced. accuracy in position.
Another drawback of the aforementioned method appears especially when the treatment is not carried out immediately after the tomography. In this way some markers can be released, for example, during the night, which can cause great difficulties in referencing. A particularly unfavorable case occurs when markers that have been released from the patient are placed on their own elsewhere; this can even lead to erroneous treatments.
Another navigation system based on the preparation of reference markers is known from the publication US-A-5,383,454. Here, separately prepared and actively radiating markers are used, which also leads to the above-mentioned drawbacks.
From the publication US-A-6,006,126 a device is known according to the preamble of claim 10 of the patent. It is proposed to produce light patterns on the head of a patient by means of a laser scanner or an optic scanner. However, laser scanners are very bulky and not flexible at all. They are placed only once in a certain place, where they remain, which originates the need to bring the patient each time to the radiation area of the scanner when it is necessary to perform a referencing or registration with such devices. Furthermore, with such a stationary laser scanner, it is not possible to launch and scan a light pattern in areas of the patient's head whose surface forms an angle of 90 ° or more with the direction of radiation, that is, in areas of the patient's head. patient who are "in shadow" in the direction of radiation. To provide or scan such areas with a light pattern, the patient would have to be rotated and this in turn entails displacement difficulties in the total registration.
From the publication US-A-5,851,183 it is known to use an optical scanner to register the frontal area of the patient by means of a scan. These purely optic registration scanners with which to explore the surface of an object require very complicated detection software and require such a high computational effort that their use is hardly possible in practice. Furthermore, for the exact referencing according to US-A-5,851,183, the position of an arch fixed to a front support must also be recorded at the same time.
On the whole, it should be noted in the use of such optical laser scanners that they are very inflexible and very expensive devices.
It is the task of the present invention to propose a procedure and a device to reference a patient or a body part of a patient in a camera-assisted medical navigation system, which overcome the inconve2
ES 2 180 481 T3 nients previously indicated regarding the current state of the art. In particular, an exact and error-free referencing must be made possible, which can be carried out simply and inexpensively.
This task is solved according to the present invention by means of a procedure to reference or register a patient or a body part of a patient in a camera-assisted navigation medical system with the following phases:
- the body part of the patient to be referenced is placed in the detection zone of a navigation system assisted by at least two cameras, which records, assisted by computer, the three-dimensional spatial positions of the light markings,
- by means of a beam of light from a manual light bulb, luminous markings are produced on the surface of the body part to be referenced, the three-dimensional position of which is determined by the camera-assisted navigation system, and
- Using the position data for the light markings, the spatial position of the surface of the body part to be referenced is determined.
In other words, the present invention desists from placing separate markings on the surface of the body part of the patient, but produces these markings simply by radiation of light on the surface (skin surface, bone surface). By irradiation of light, a luminous point is produced on the surface that is as visible to cameras as the radiation of a marking. Now crossing the surface with this ray of light, a large number of luminous markings is produced in the practice, and the composition of these luminous markings known in space as three-dimensional points of light, results in a set or cloud of points associated with the surface of the body part to be treated. Theoretically, the three-point register is sufficient; the procedure is more stable with the production of more points. With a sufficient number of these points, enough information is obtained to be able to coordinate the surface in a very precise way. The tests have shown that a reduced number (about 20) of light markings produced in this way is sufficient to be able to determine with good accuracy the spatial position of the body part.
In general, it is valid that such areas of the patient are illuminated with the light beam and can thus be found in the corresponding patient data set. With this, the referencing or registration is also possible when the patients are scanned without any accessory by means of an imaging procedure and then in the referencing or in the registration those accessories are already shown (for example, tubes in the nose).
The advantage of the present invention thus consists, together with the high achievable accuracy, that all the problems that occur with separately placed markers are overcome. Referencing is no longer affected by possible translated, displaced or deleted markers. The reference according to the present invention does not practically entail any unpleasant side effects for the patient, such as perhaps discomfort from glued or fixed markers, perhaps in an invasive way. Wrong markings of isolated light or reflections, for example, "missed shots" such as rays reflected on surfaces other than the desired one, can be rectified without further ado by the computer.
Another great advantage of the present invention is that, by not having to place markings separately, the large-scale treatment can be decoupled in time from the tomographic recording. Since the surface of the patient's skin will not change essentially over a long period of time, it is possible to still accurately reference the patient, even a few days after the tomographic recording, without it being necessary for the patient to maintain markings on the surface. of your skin during this long period of time.
In addition, the present invention has an advantageous impact even on the scan registration of the patient. Until now, special scans (navigation scans) have been carried out, that is, scans that include markers visible by CT or MR. The present invention now makes it possible, since markerless scans are performed, on the one hand, to decouple the scan from the operation in time, but, on the other hand, to use the desired scans for navigation purposes. Therefore, if a doctor determines before the operation that another CT scan performed a few weeks ago might be useful during navigation, he can use it without problems during navigation, since the markers do not need to be represented in such a scan.
Furthermore, it is advantageous that an already available per-camera system can be used by the technology according to the present invention, that is to say that no additional apparatus is required, such as, for example, a laser scanner. Compared to conventional procedures in which the detection or registration of points takes place with a navigation pointer (that is, the bone surface is scanned with the end of a pointer, the corresponding three-dimensional coordinates of the points are stored and then this point cloud is mathemaotically harmonized to the surface obtained from the CT data), the procedure according to the present invention allows greater accuracy and faster registration.
The reference according to the present invention can be used for any treatment that requires the determination of the current spatial position of a body part of the patient. But the invention is especially suitable for procedures in which the spatial position of the surface is coordinated with a graphic data set performed with an imaging procedure for the body part, especially in a CT scan data set, MRI ( magnetic resonance tomography),
IS 2 180 481 T3
PET, SPECT, X-ray or ultrasound, to reference the current graphical data of this data set.
In principle, it is an advantage for the function of the procedure according to the present invention, if a well-differentiated point of light is produced as a luminous marking on the surface of the patient's body part. The beam should therefore be as concentrated as possible at its place of impact. The use of a non-visible light beam is shown here as particularly advantageous, since the light point thus produced can be very well differentiated from the light reflections that occur in the patient's body part due to the other lighting in the room. . Furthermore, the use of a beam of infrared light is advantageous, the cameras being set to register reflections for this light. With the use of laser light, very well defined and concentrated light markings can be obtained.
When non-visible light is used, as proposed above, to produce the light markings, it is in principle difficult to determine exactly where the light beam hits. To solve this problem, the method according to the present invention will be carried out advantageously so that, by means of a second visible light beam directed essentially to the same target area such as the non-visible reference beam, a visible light reflection. With the aid of this second light beam, it is now possible to detect very well exactly where the non-visible reference beam is incident. Also in this second ray of light it can be a laser ray of light. The aforementioned embodiment also offers another advantage in terms of avoiding dangers. As already mentioned above, due to the possibility of producing sharply outlined light markings, it is advantageous to use a non-visible laser light beam as the referencing light beam. Since the human eye cannot see this ray of light and inadvertently irradiating it into the open eye does not produce any reflex closure of the eyelid, injuries, for example retinal burns, can be caused here. If now a second ray of light with visible light is used, as proposed according to the present invention, this can serve on the one hand to support the objective, excluding sensitive areas (for example, the eyes) from the irradiation. On the other hand, this visible light when entering the eye causes the reflex closure of the eyelid, so that corneal burns are avoided.
There are in principle several possibilities to produce both rays of light. Thus, for example, two light bulbs placed side by side or two light bulbs placed one inside the other can be used here. Of course, there is also the possibility of using a single light source that radiates both visible and non-visible light.
In a preferred embodiment of the method, several consecutive light markings (dots) are produced with the referenced light beam while the position of the light markings produced is continuously recorded, namely in particular for the time necessary until the sufficient number is collected. of position data to determine spatial position. Here, moreover, there is the possibility of letting the assistant computer continuously check, by means of a matching procedure, during referencing whether it already has enough light markings to coordinate the number of referenced points on the surface of the graphical data set ( for example, tomography). In the event that sufficient data is available at any given time, an optical or acoustic signal can be emitted to indicate that the referencing has been completed successfully.
In another advantageous embodiment of the procedure according to the present invention, the body part to be referencing is moved during referencing in such a way as to eliminate camera shadows, the movement of the body part being closely followed by an arrangement of markings on the navigation system, arranged in front of the body in a fixed position. Since the cameras are mostly installed in a fixed way, they will give as a result, especially in the referenced in certain places of the face, points that are in the camera shadows, that is, for example, behind a nasal fin. When these points are also illuminated with light markings and it is desired to record these markings, it is advantageous to move the patient. In order for this movement not to corrupt the record, it must be followed in the navigation system, which occurs with the aforementioned arrangement of markings, that is, for example, via a Mayfield three-armed reference adapter with a known arrangement of markers.
According to the present invention, a device is also provided to reference or register a patient or a body part of a patient, with a navigation system assisted by at least two cameras, by means of which the three-dimensional spatial positions of luminous markings in a detection zone, and with a means for registering luminous markings on the surface of the body part to be referenced, The three-dimensional spatial position of which is determined by the camera-assisted navigation system, the means for registering light markings being a manual light source that produces light reflections on the surface as light markings. The manual light source can be a non-visible light source, especially infrared light, the cameras being adjusted to the register of reflections for this light. The manual light bulb can also be a laser light bulb.
Preferably, the hand-held light source radiates a second visible light beam, which is directed essentially towards the same target area as the non-visible reference beam, additionally producing a visible light reflection on the surface. Visible laser light can also be radiated from this second light source. For this, the light sources for the light rays can be united in a single light source, two light sources can be side by side or one inside the other.
IS 2 180 481 T3
Advantageously, the device further comprises an arrangement of markings, arranged in a fixed position in front of the body part, by means of which the movements of the body part to be referenced are followed during referencing to eliminate camera shadows.
Rather, a camera movement can naturally be followed. In most cases it is advantageous that the body part of the patient to be treated remains fixedly still during the treatment and also during the referencing or recording. In this case, camera shadows can be avoided by changing the cameras from their position. Since the marking arrangement provides other images from different camera angles, it is also possible in this case to follow the relative movement between the cameras and the body part and take it into consideration in the referencing.
The advantages that are pursued with the device according to the present invention are the same that have been discussed above with respect to the method according to the present invention.
In the following, the present invention is clarified in greater detail with the aid of one embodiment. The attached figure shows schematically the use of a referencing device according to the present invention, by means of which the position of a patient or a body part of the patient is referenced or recorded.
In the figure of the camera-assisted navigation system, the computer with on-screen emission is schematically represented and indicated in conjunction with 9. This computer is connected by cable 8 with the camera support 4, in which they have been arranged two infrared cameras 5 and 6 at a distance, which control the treatment area.
The position of the represented human head must be referenced or recorded. The manual light bulb 1 is used for this, which radiates a beam of infrared laser light 2, and specifically on the surface of the patient's face. The hand-held light bulb 1 is again shown in dashes in a second position to represent that it can be continuously tilted during referencing.
With the referenced light beam 2, it is now possible to traverse the surface of the face, producing reflections or light points 3 arranged one after the other on the surface. In the drawing, only some such light markings have been represented, by way of example, and specifically by light points aligned next to each other in a line. But in general, points or reflections can also be produced immediately by radiation in the appropriate places.
Before effective treatment, the practitioner simply grasps the manual light bulb 1 by hand and traces the light beam 2 over the surface of the face for a time. Thus, due to the rapid succession of recordings of individual images, light reflections 3 are produced for the camera system, arranged one after the other, whose light path for a point is represented in the drawing with the line of dashes and dots 7. Both cameras can register three-dimensionally the position of the light reflection in space and the computer system 9 can then, from the data of the registered light markings, determine points associated with the position of the surface of the face.
The computer stores the data from a scan for the patient's head and thus also the data for the surface of the face. The computer now finds out, with the help of a continuous matching procedure, if the number of graphical points of the referenced by light rays is sufficient to associate and cover the recorded surface points, as it knows them from the data set of scanning. When there is sufficient agreement here, an optical and / or aquatic signal is emitted that indicates to the physician that the referencing has ended successfully.
The graphic dots 3 produced therefore replace markings glued or placed in a different way than how they have been used separately up to now. By obtaining a multitude of luminous graphic points 3 it is possible to carry out a very precise referencing.
Furthermore, the figure schematically represents that in the patient's head there is also a reference adapter 10 in a fixed position. This adapter has three reflectors whose position can also be followed by cameras 5, 6. If it is now necessary during referencing to rotate the patient's head or move the chambers 5, 6 to, for example, eliminate camera shadows behind a nasal flap, the relative movement is followed with the help of the adapter 10 and is included in the referencing , so that registration errors do not occur.
As already mentioned above, the manual light bulb 1 can irradiate, in addition to the non-visible light beam 2, another visible light beam in the same direction and with the same focus, to allow the practitioner to track the light spots produced by optically. and avoid radiation to the eyes.
The reference system according to the present invention can be used in all treatment methods that include an image-assisted operation activity. This is valid both for surgical operations as well as for radiation treatments. Referencing can also be used both for tracking systems with passive marker arrangements, as well as for those with actively radiating markers, as used, for example, for tracking medical instruments. Even though the production of luminous markings by means of a light beam on the surface of the patient's skin has already been widely discussed, it is within the framework of the present invention to reference in the same way, for example, already discovered bone structures. for treatment, for example, cranial aosseous sections or parts of the spinal column.
Contents4
1 sheet
Sheet 1
12 members in 6 offices
Priority claims3
| Document | Office | Kind | Date |
|---|---|---|---|
| 00107088 | European Patent Office (EPO) | A | |
| 00107088 | – | – | – |
| EP20000107088 | – | – | – |
Members12
| Document | Office | Kind | |
|---|---|---|---|
| EP1142536A1 | European Patent Office (EPO) | A1 | |
| US2002002330A1 | United States of America | A1 | |
| JP2002035007A | Japan | A | |
| EP1142536B1 | European Patent Office (EPO) | B1 | |
| AT221344T | Austria | T | |
| ATE221344T1 | Austria | T1 | |
| DE50000335D1 | Germany | D1 | |
| ES2180481T3This record | Spain | T3 | |
| US6873867B2 | United States of America | B2 | |
| US2005143645A1 | United States of America | A1 | |
| US7577474B2 | United States of America | B2 | |
| JP4938933B2 | Japan | B2 |
Numbers
- Publication
- 2180481
- Publication, DOCDB
- 2180481
- Publication, EPODOC
- ES2180481T
- Application
- 107088
- Application, DOCDB
- 00107088
- Application, EPODOC
- ES20000107088T
Titles2
- Spanish
- REFERENCIACION DE UN PACIENTE EN UN SISTEMA DE NAVEGACION MEDICA, UTILIZANDO PUNTOS LUMINOSOS PROYECTADOS.
- English
- REFERENCE OF A PATIENT IN A MEDICAL NAVIGATION SYSTEM, USING PROJECTED LIGHT SPOTS.
Classification
- CPC, 9
- A61B90/36
- A61B2018/2025
- A61B90/10
- A61B2034/2055
- A61B2034/2072
- A61B2090/364
- A61B34/20
- A61B90/39
- A61B2090/3937
- IPC, 8
- G01B11 00
- A61B18 20
- A61B34 20
- A61B90 00
- A61N5 10
- G06T1 00
- H04N5 225
- H04N5 232