This application relates to magnetic levitation based devices, systems and techniques for various applications including medical diagnosis and surgery applications.
Magnetic levitation techniques apply a magnetic field to levitate or suspend a magnetic object based on the interaction between the magnetic object and the applied magnetic field. The magnetic field is designed in a way so that the interaction counteracts other forces exerted on the object such as the gravitational force. When the magnetic object is a paramagnetic or ferromagnetic, stable magnetic levitation requires the levitated magnetic object to be placed at a location where the levitating magnetic field has a maximum. Because a magnetic field in free space cannot have a maximum, stable magnetic levitation is impossible for a paramagnetic or ferromagnetic object. This is known as the Earnshaw's theorem.
Stable magnetic levitation can be achieved, however, when a levitation system is designed to violate the conditions for the Earnshaw's theorem. For example, a diamagnetic material can be levitated and stabilized. See, “Magnet levitation at your fingertips” by A. K. Geim, M. D. Simon, M. I. Boamfa, and L. O. Heflinger in Nature, vol. 400, p. 323-324 (1999); “Diamagnetically stabilized magnet levitation” by M. D. Simon, A. K. Geim and L. O. Heflinger in America Journal of Physics, Vol. 69(6), p. 702-713 (2001). A magnetic object can also be levitated and stabilized in a magnetic system with an electronic feedback control to dynamically adjust one or more electromagnets in the system to stabilize the magnetically levitated object at a desired location. One example of a dynamically controlled magnetically levitated system is the electromagnetic suspension (EMS) magnetic levitation train where a servo control system adjusts a magnetic force at a constant distance from the track.
The specification of this application describes, among others, embodiments and implementations of techniques, apparatus and systems for implementing a servo controlled magnetic levitation system that magnetically levitates and controls a magnetic platform to navigate in a confined space to obtain capture images of or other information of the confined space. A servo control is provided to control the magnetic field that levitates the magnetic platform to stabilize the levitated magnetic platform. The magnetic platform can be equipped with instrumentation to perform other operations in the confined space. The confined space may be a location with a chemical or biological hazard substance so the magnetic platform can be used to detect such substance. In medical applications, the magnetic platform can be inserted into a patient's body to perform medical diagnosis or surgery with a significantly reduced level of incisions.
In one embodiment, for example, a magnetic levitation system can be implemented to include a frame that includes magnets to produce a variable magnetic field, magnetic field sensors mounted to the frame to measure the magnetic field, a magnetic platform formed of a magnetic material and configured to be magnetically levitated by the magnetic field, and a feedback control module to receive sensor signals from the magnetic field sensors and, in response to the sensor signals, to control the magnets to adjust the magnetic field to levitate and to stabilize the magnetic platform. The magnetic platform includes a video camera to capture video images and a wireless communication unit to wirelessly transmit the video images outside the magnetic platform.
In another embodiment, for example, a magnetic levitation medical system includes a frame structured to define a surgical space that accommodates a surgical table for holding a patient, the magnetic frame comprising a top frame part above the surgical space. This system includes a magnet system which includes (1) a plurality of lifting magnets mounted to the top frame part to produce a static magnetic field within the surgical space below the top frame part to exert a magnetic lifting force on a magnetic material against the gravity, and (2) at least one electromagnet mounted to the top frame part to produce an adjustable magnetic field in the surgical space. Magnetic field sensors are mounted to the frame to measure the magnetic field in the surgical space. This system also includes a magnetic platform formed of a magnetic material and configured to be magnetically levitated by the magnet system to levitate in the surgical space without a mechanical attachment and without a communication cable. The magnetic platform includes at least one of a diagnostic probe that performs a measurement and a surgical tool that performs a surgical operation. A feedback control module is provided to receive sensor signals from the magnetic field sensors and, in response to the sensor signals, to control the magnet system to adjust the magnetic field in the surgical space to stabilize and to control a position and motion of the levitated magnetic platform.
In yet another embodiment, a method is described for operating a magnetically levitated platform to conduct a surgical operation within an abdominal cavity of a patient. This method includes providing a magnet system to produce a variable magnetic field that defines a magnetic levitation region above a surgical table to levitate a magnetic platform and to control a position and motion of the magnetic platform; placing the patient on the surgical table to position the abdominal cavity in the magnetic levitation region; inflating the abdominal cavity with a gas; and inserting the magnetic platform inside the inflated abdominal cavity to levitate the magnetic platform. Next, this method provides controlling the variable magnetic field in the magnetic levitation region to levitate the magnetic platform in the inflated abdominal cavity and to stabilize the magnetic platform; using a camera on the magnetic platform to capture one or more images of inside the inflated abdominal cavity including the target; and wirelessly transmitting the one or more captured images from the camera outside the patient's body to display on a display screen. This method further provides moving the relative position or orientation of the magnet system with respect to the surgical table to move the levitated magnetic platform near a target area within the inflated abdominal cavity; and wirelessly controlling a surgical instrument mounted on the levitated magnetic platform to perform a surgical operation on the target area within the inflated abdominal cavity.
These and other examples and implementations are described in detail in the drawings, the detailed description, and the claims.
The magnetic levitation apparatus, systems and techniques described in this application may be used in medical surgical and diagnostic applications, detection of a hazardous condition, chemical or biological substances and other conditions in confined space, and other applications. One example of the present magnetic levitation systems can include a frame comprising magnets to produce a variable magnetic field, magnetic field sensors mounted to the frame to measure the magnetic field, a magnetic platform formed of a magnetic material and configured to be magnetically levitated by the magnetic field, and a feedback control module to receive sensor signals from the magnetic field sensors and, in response to the sensor signals, to control the magnets to adjust the magnetic field to levitate and to stabilize the magnetic platform. The magnetic platform includes a video camera to capture video images and a wireless communication unit to wirelessly transmit the video images outside the magnetic platform.
Implementations of this and other magnetic levitation systems described in this application may be configured for medical and surgical uses. The following examples provide some details for specific medial surgical and diagnostic uses in which the magnetic platform is levitated and is remotely controlled and inserted into hard to reach cavities and spaces. While in these spaces certain functions could be performed according to the tasks needed. The basic function is transferring images such as live streaming video images of that space and further functions can include handling its surrounding i.e. moving parts, repairing, achieving biopsies or samples or performing surgery. For medicine use, this platform can be inserted to a cavity of a subject, e.g., the peritoneal cavity, the gastrointestinal tract, the nasopharyngeal space, and the oral cavity.
Such a magnetic levitation system can be used to provide Minimal Invasive Surgery (MIS) in areas such as the abdominal and chest regions. MIS has gained a major role in the various surgical procedures during the last decade. Laparoscopic cholecystectomy is possibly the most common laparoscopic operation and on 2003 between 500,000 to 600,000 laparoscopic cholecystectomies were performed in the US, which comprised 25% of the operations in general surgery that year. Since then laparoscopic surgery has become even more common (on 2003 the CDC estimated that 750,000 operations were performed in the US) and today minimal invasive surgery is the preferred type of surgery in many types of operations.
MIS operations can be performed in various ways. For example, small incisions in the abdominal wall can be made to perform MIS operations. As a specific example, the first step of the MIS operation can be to inflate the abdominal cavity with a gas (e.g., the CO2 gas) in order to create a working space. Then, several 5-12 mm skin incisions are performed and trocars (plastic or metallic sheaths which serve as ports of entry) are inserted into the abdominal cavity through these incisions. The laparoscope (camera attached to a shaft with lenses and fiber optic cables) is inserted through one of the trocars and enables the vision of the abdominal organs on a TV monitor placed beside the patient. Insertion of long instruments through the other trocars follow, which enable performing the surgery. Among the major advantages of MIS are the small incisions that cause less trauma to the abdominal wall and hence a lesser degree metabolic response to trauma. Also the small incisions cause less post operative pain and therefore less respiratory complications. The operation itself is performed through a magnified image with enhanced vision and lighting which enables operating in deep abdominal space without difficulty. Due to the minimal abdominal trauma and reduction of post operative pain the length of hospital stay decreased significantly. The cosmetic results can be better than some other surgery procedures that have been used by surgeons.
In some implementations, the above described MIS operations can have some disadvantages. For example, the operation is performed using two dimensional vision on the TV monitor and such vision can limit the precision of the operation. Such operation also lacks the tactile sensation and thus is limited in precision and other aspects. The operating field can be restricted to the camera field of view. Such operations tend to involve certain counter intuitive movements and thus may require special expertise. As yet another example, in such operations, the field of the operation is usually restricted by the choice of the primary incisions.
In an operation by the MIS methods, inserting instruments through the abdominal wall may create a hinge for the movements of these instruments. The hinge is located where the incision is made and hence the instruments may experience restricted movement which is determined by the choice of the incision location. The approach to an organ in the abdomen is determined by the point of entry on the abdominal wall and the point of contact with that organ. Because these two points define one straight line, these two points dictate the direction along which this organ can be approached. If the surgeon wants to approach the organ from a different angle he needs to make another incision on the abdominal wall and insert the instrument from there. Currently the camera used for MIS is attached to a shaft comprised of lenses which convey the image from within the abdomen. The same restriction applies to the camera. The surgeon may not always be able to view the organs from a desired angle and this condition can compromise the vision capabilities in making further incisions.
A magnetic levitation system described in this application can be applied to MIS operations and to address one or more issues discussed above. A magnetic levitation medical system include, for example, a frame structured to define a surgical space that accommodates a surgical table for holding a patient, the frame comprising a top frame part above the surgical space; a magnet system which includes (1) lifting magnets mounted to the top frame part to produce a static magnetic field within the surgical space below the top frame part to exert a magnetic lifting force on a magnetic material against the gravity, and (2) at least one electromagnet mounted to the top frame part to produce an adjustable magnetic field in the surgical space; and magnetic field sensors mounted to the frame to measure the magnetic field in the surgical space. In some implementations, at least one of the magnetic field sensors may be mounted to the top frame part. This system also includes a magnetic platform formed of a magnetic material and configured to be magnetically levitated by the magnetic system to levitate in the surgical space without a mechanical attachment and without a communication cable. This magnetic platform includes at least one of a diagnostic probe that performs a measurement and a surgical tool that performs a surgical operation. The sensor signals generated from the magnetic field sensors can be used to extract position information of the magnetic platform. Other position sensors different from the magnetic field sensors may also be implemented. This system further includes a feedback control module to receive sensor signals from the magnetic field sensors or other position sensors and, in response to the sensor signals, to control the magnet system to adjust the magnetic field in the surgical space to stabilize and to control a position and motion of the levitated magnetic platform.
Having the magnetic platform that levitates in the abdominal cavity provides a number of advantages. For example, this platform can change its location within the cavity by remote control and hence achieving the desired angle of approach to the organs without adding further incisions on the abdominal wall. The levitating platform can be equipped to perform different tasks. For example the basic device would be a miniature wireless camera. This camera may include two imaging sensors such as two CMOS sensors as to achieve a 3D vision and will transmit live video images to the outer portion of the cavity. A computer processor can be used to process the captured images to enhance the images and allow the 3D vision for the operator. In order to visualize inside a dark cavity as the abdomen a LED light source and a DC power source may be harbored on the platform as well.
In some implementations, the magnetic platform can incorporate selected Robotic surgery (MIS using robotic assistance) mechanisms. A laparoscope used in robotic surgery, for example, can be implemented on the magnetic platform to enable 3 dimensional vision; in another example, computer software can be used to enable tremor elimination and fine tuning of the surgeons movements and the counter-intuitive movements are translated automatically by the robot to the more friendly intuitive movements.
In other MIS surgical operations, it can be difficult to overcome the restriction of the field of vision by the placements of the trocars, and the restriction of the direction of the working instruments. The lack of possibility to visualize the side part of the organ operated upon and the need for a “blind” dissection of tissues due to that fact poses a major disadvantage to MIS and robotic surgery. As long as the camera and the working instruments are inserted through trocars, the hinges created at the abdominal wall can restrict their movement and direction of manipulation inside the abdominal cavity.
The present magnetic levitation technology can be configured in ways that mitigate these and other issues using the levitated magnetic platform which is remotely controlled and acts as a medical diagnosis and surgical device vehicle. The platform can harbor a video camera which transmits live streaming video images via wireless connection from within the cavity to a receiver placed outside of the cavity. These images are viewed on a monitor or a 3D visor when a 3D camera is used. According to the images acquired, the movement of the platform is controlled, in real time, by the operator according to his commands, on matching “joysticks” in the console. The platform can be moved in 3 axis directions in relation to the cavity by moving the lifter magnet complex or moving the cavity itself. The platform can be used as the only tool for the procedure when harbored with a camera, light source and surgical instruments or as an adjunct when harbored with only a camera to aid in the visualization or only instrumentation to perform the procedure when achieving video images from another source. Among various advantages and benefits, such a magnetic levitation system can be implemented in a way to perform the procedure having a better vision and better access to the organs with fewer incisions on the abdominal wall.
The instruments harbored on the platform could be moved as one part of the platform or independently relatively to the platform. In one example, the operating instruments can be specially constructed using MEMS technology which enables the instruments to be small, receive wireless signals interpret them and translate them into the ordered movements.
Various magnetic levitation systems and techniques are known and have been applied in various areas of industry and in the toys industry. In some systems, the levitation gap used is of a few millimeters to a few centimeters mostly in order to accelerate speed of rotating/moving parts and diminishing the friction. The systems described in this application can be implemented by using dynamically controlled feedback to control the magnetic fields and to stabilize the levitated platform with a gap of tens of centimeters, e.g., 10-20 cm, to provide sufficient space for medical surgical and diagnostic operations through instrumentation on the levitated platform. Magnetic position sensors and feedback control of the magnets provide remote control of the levitated platform.
The present magnetic levitation systems and techniques can be applied to other applications, including but not limited to, handling of hazardous materials (radioactive substances, dangerous gaseous materials, highly infectious organisms), and gentle mechanical work in confined areas or outer space. Such applications can allow for minimal human contact and provide maximal precision. These remotely controlled systems may be operated from a distance further than a few meters, by internet connections. This way expertise of certain procedures could be shared worldwide with out the necessity to transfer patients, physicians or other expert personnel across countries.
The total magnetic field produced at the surgical space can magnetically levitate the magnetic platform with a large gap with its surroundings so that it can be moved inside a cavity of a patient placed on a surgical table. One or more electromagnets can be used to create the appropriate time changing magnetic field and the magnetic field sensors are used to measure the position and motion of the platform. A control circuit can be used to keep the platform stably levitating by controlling the current to one or more electromagnets or the field shaping magnets. Motion control for the subject cavity or for the field shaping magnets can also be provided as part of the system control to move the levitated platform. The levitated platform can be controlled and positioned in a gas-filled or vacuum cavity. The large gap, that is, the large clearance volume above, below, and to the sides of the levitating platform is meant to accommodate the human body undergoing a laparoscopy procedure, heart/lung or other surgery. For example, the levitated platform can be controlled at the center of a one cubic foot volume with no part of the levitation apparatus closer than 6 inches in any direction. The magnet platform can be configured to fit into the cavity opening and structured to support instrumentation for medical surgery or diagnostic measurements.
The field shaping magnets are arranged so that the magnetic field has the proper direction, gradient and curvature at the desired levitation point where the platform levitates. The field direction keeps the platform from overturning and the gradient is set at an appropriate value and along an appropriate direction to balance out the gravity at the levitation point. The magnetic field curvature determines which directions are stable for the platform and which directions are unstable. The feedback control is used to control magnetic field that levitates the platform to stabilize the platform. Various configurations for the field shaping coils are possible. As an example, the system in
The magnets in
Two electromagnet controls may be applied in implementations and other methods are also possible. The first is analog control, where the amplitude of the electromagnet current is varied. The second is pulse width modulation where the current is driven on full each time but the width of the pulse is varied. One design uses a bipolar system where the coil can be driven with positive or negative current but unipolar designs are also possible. Both amplitude and pulse width modulations can be used.
Some technical challenges in implementations include: large separation between the magnet platform and the hall sensor may cause the error signal to be smaller than the noise in the hall sensor; pulsing of the control coil may rail the Hall signal from each magnetic sensor. To overcome these problems, a sample, average, and hold scheme can be implemented in analog circuitry, in digital processing (e.g., via processing software) or a combination of analogy circuitry and digital processing. The electromagnet is turned off for a brief period of time. During this time the Hall sensor signal is put through a set of filters (analog or digital) and amplifiers, and the output is averaged and then the average value is latched. The generated error value is used to set the amplitude of the electromagnet current for a set period of time. This process is repeated (e.g., over 1000 times a second). The signal noise is reduced as the averaging time increases. The averaging time is limited below a certain value to keep the response of the control sufficiently fast. The control can be implemented as a phase lead network or analog or digital PID controller.
There are several options of controlling the platform movement depending on configurations of the lifter magnets and magnetic sensors. The following are some examples.
In a configuration that the lifter magnets are above the OR table and the sensor is at the same place, the platform movement can be controlled by moving the lifter magnet complex. The operator can use a control device such as a joystick on the control console in
In a configuration that the sensors are not positioned in the lifter magnet complex the sensor is moving synchronously with the lifter magnets using the same computer software for both complexes (lifter magnets and sensors).
A different way to achieve the relative movement of the platform to the patient is by moving the patient while the platform is stationary. The patient moves due to the joystick movements that control the movement of the OR table via computer control software in the system. The lifter magnet complex stays stationary and therefore the levitated platform as well. In this way the movement of the platform is relative to the patient and achieves the same result. This is a lesser preferred way due to the necessary movement of the anesthesia equipment. The organs might move as well due to the changes of gravity forces while tilting the table in the horizontal plane.
A third way of controlling the platform movement is a combination of the lifter magnet complex movement and the OR table movement. In this configuration the default is moving the lifter magnet complex. If necessary the computer software can be used to add the additional distance desired by moving the OR table.
An example flow of operations for operating a patient using the magnetic levitation system is now described. First, the patient is positioned on the OR table and anesthesia, prep and drape are performed. The surgery begins with a small incision (e.g., a 2.5 cm cut) on the abdominal wall at a suitable location which can be selected based on the patient's specific conditions and requirements such as previous scars, previous surgery and cosmetic results. The designated laparoscopic instrument is then inserted through the trocar and hold the platform with the lap instrument. The platform is then inserted into the abdominal cavity through the incision. Next, the fascial incision is sutured tight around the trocar and subsequently the peritoneal cavity is filled with a gas (CO2) to inflate, thus forming the working space as in laparoscopic surgery.
At this time, the magnets of the system are controlled to levitate the platform inside the cavity and to stabilize and lock the platform in the magnetic field. The medical surgery or diagnostic procedure is then performed using the levitated platform. Following the termination of the procedure, the levitated platform is moved to the incision site. Insert the lap instrument and hold the platform. Next, the levitation magnetic field is shot down to remove the platform through the incision. Finally, the surgeon sutures the incision to complete the procedure.
Hence, in one implementation, a method for operating a magnetically levitated platform to conduct a surgical operation within an abdominal cavity of a patient can include: providing a magnet system to produce a variable magnetic field that defines a magnetic levitation region above a surgical table to levitate a magnetic platform and to control a position and motion of the magnetic platform; placing the patient on the surgical table to position the abdominal cavity in the magnetic levitation region; inflating the abdominal cavity with a gas; and inserting the magnetic platform inside the inflated abdominal cavity to levitate the magnetic platform. Next, this method provides controlling the variable magnetic field in the magnetic levitation region to levitate the magnetic platform in the inflated abdominal cavity and to stabilize the magnetic platform; using a camera on the magnetic platform to capture one or more images of inside the inflated abdominal cavity including the target; and wirelessly transmitting the one or more captured images from the camera outside the patient's body to display on a display screen. This method further provides moving the relative position or orientation of the magnet system with respect to the surgical table to move the levitated magnetic platform near a target area within the inflated abdominal cavity; and wirelessly controlling a surgical instrument mounted on the levitated magnetic platform to perform a surgical operation on the target area within the inflated abdominal cavity.
Locking of the platform in the levitation magnetic field can be achieved in different processes. For example, a manual locking process may be performed following the insertion of the platform into the abdominal cavity while being held by the laparoscopic instrument the abdominal cavity is insufflated. After the platform is inserted and the cavity is inflated, the magnetic field is powered on and the operator moves the platform using the lap instrument in the abdominal space. The sensor captures the platforms location and displays to the operator where the locking point is. The display shows the necessary movement in order to locate the platform in locking position (up/down, forward/backwords). Once the platform is in place the display signals “locked” and the operator can gently let go of the platform which can stay levitated in the abdominal cavity.
An automatic locking process can also be used following the insertion of the platform into the abdominal cavity. After the insertion, the operator leaves the platform resting on the abdominal organs. The abdomen is then insufflated and the sensor is turned on without turning on the levitation magnetic field. The sensor senses the location of the platform and then two signals are sent to the computer controlling the movements: a first signal indicating the location of the platform and a second signal indicating the calculated locking point according to the lifter magnet complex location. The software then moves the lifter magnet complex and/or the OR table until the platform and the calculated locking point overlap. Following the operators approval the magnetic field is turned on and the platform is locked. The operator then elevates the platform (either by elevating the lifter magnet or lowering the OR table) and the platform stays levitated in the abdominal cavity.
In implementations of the described magnetic levitation systems in medical uses, different procedures for diagnosis and surgery may be used. In one example, instead of inserting a long tube (endoscope) through the mouth into the stomach which has some risks to the patient and discomfort, the patient can swallow this platform. A thread can be attached to the platform for later retrieval of the platform. Once the platform is inside the stomach, the levitation magnetic field is turned on to levitate the platform. Next, the video camera on the platform can be used to observe the inside of the stomach and biopsies or operations can be performed by the platform if needed. Upon completion of the procedure, the platform can be retrieved using the attached thread (rather than the large endoscope) that is inserted to the stomach via the mouth and grab the platform and pull it back to the mouth.
In another example, the magnetic levitation system is used to implement Natural Orifice Translumenal Endoscopic Surgery (NOTES), one type of Minimal Invasive Surgery operations. In this approach the surgery is done by inserting the magnetic platform through the mouth into the stomach and using the inserted platform to make an incision on the stomach wall from the inside. After the incision, the platform is pushed into the abdominal cavity like in laparoscopy. The platform can be miniaturized to allow for such incision and insertion. After the platform is pushed into the stomach and out to the abdominal cavity, the platform is then levitated and is controlled to move around inside the abdominal cavity to capture images and to perform surgical or diagnostic procedures.
One example of using a magnetic levitated system to perform a medical procedure can be conducted as the following: placing a patient on the surgical table to position the abdominal cavity in the surgical space; inflating the abdominal cavity with a gas; inserting the magnetic platform into the stomach through the patient's mouth; controlling a video camera in the magnetic platform to capture video images inside the stomach; and wirelessly transmitting the captured video images from the camera outside the patient's body to display on a display screen. Next, in this example, a surgical instrument mounted on the magnetic platform is wirelessly controlled to make an incision on a wall of the stomach. The magnetic platform is then moved out of the stomach through the incision into the inflated abdominal cavity and the magnet system is controlled to levitate the magnetic platform inside the inflated abdominal cavity. Subsequently, the video camera in the magnetic platform is operated to capture video images inside the inflated abdominal cavity and the captured video images from the camera are wirelessly transmitted outside the patient's body to display on a display screen. The relative position or orientation of the magnet system with respect to the surgical table is controlled to move the levitated magnetic platform inside the inflated abdominal cavity to search for a target area based on the displayed video images on the display screen. A surgical instrument mounted on the levitated magnetic platform is wirelessly controlled to perform a surgical operation on the target area within the inflated abdominal cavity. In the above, after completion of the surgical operation, the magnetic platform may be moved from the inflated abdominal cavity into the stomach through the incision and may be subsequently retrieved from the stomach through the patient's mouth.
While this specification contains many specifics, these should not be construed as limitations on the scope of an invention or of what may be claimed, but rather as descriptions of features specific to particular embodiments of the invention. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or a variation of a subcombination.
Only a few implementations are disclosed. However, it is understood that variations and enhancements may be made.
This patent application claims the benefit of U.S. Provisional Application No. 60/887,548 entitled “MAGNETIC LEVITATION BASED DEVICES, SYSTEMS AND TECHNIQUES FOR PROBING AND OPERATING IN CONFINED SPACE, INCLUDING PERFORMING MEDICAL DIAGNOSIS AND SURGICAL PROCEDURES” and filed on Jan. 31, 2007, the disclosure of which is incorporated by reference as part of the specification of this application.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US08/52466 | 1/30/2008 | WO | 00 | 8/17/2009 |
Number | Date | Country | |
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60887548 | Jan 2007 | US |