Patent Application
20050075563
For certain surgical treatments, the precise location of an instrument, such as a probe or needle, within a patient's body is critical. For example, particular medicines can be delivered via a needle to a precise location within the body. One such application is the delivery of an anti-cancer drug to the exact location of the tumor.
Doctors have used fluoroscopy to track the position of the needle into the body as it is inserted to the desired location. However, fluoroscopy only provides the doctors with a two-dimensional view of the needle's position in the body. As a result, it has been proposed to use a computed tomography scanner in order to provide a three-dimensional view of the position of the needle as the doctor inserts it into the body. The CT scanner operates continuously in order to provide an up-to-date three-dimensional view of the needle's position.
However, both the fluoroscopy and the CT scanner expose the doctor and the patient to radiation. Therefore, it has also been proposed to use robots, remotely controlled by the surgeon watching the CT image, to insert the needle into the patient's body. In these systems, the CT scanner includes an x-ray source and an x-ray detector on opposite sides of the patient's body near the needle. The x-ray from the x-ray source is collimated to emit a fan-beam x-ray producing a plurality of “slices” through the patient's body as the x-ray source and detector revolve around the patient's body. The doctor views the three-dimensional image while remotely controlling the needle's position in the patient's body. In this manner, the doctor can avoid the unnecessary doses of radiation.
This proposed CT system has some drawbacks. First, because the x-ray source is a fan-beam x-ray source, imaging only a narrow slice at a time, it is difficult to keep the tip of the needle in the field of view. This is particularly true when the needle is traveling generally parallel to the axis of rotation of the CT scanner. The CT scanner is fixed in the room, so the patient bed, the patient and the robot must be translated along the axis of rotation of the CT scanner to keep the needle tip in the field of view. Additionally, although the doctor can avoid excessive doses of radiation by using the robot, the continuous scanning by the CT scanner exposes the patient's body to more radiation than necessary.
The present invention is an image-guided surgical system including a CT scanning system, for example, for use with robotic intervention.
The CT scanning system includes a source and detector mounted to a c-arm positioned on a carriage, such that the c-arm can be rotated about an axis centered within the c-arm. The carriage is also slidably mounted on rails such that the carriage and c-arm can translate along the axis. The system further includes a surgical robot for inserting a needle into a patient's body.
A controller controls the source, detector, surgical robot, and any hardware for moving the c-arm. The controller may be a CPU including a display and an input device. The CPU gathers the data and images from the detector and generates a three-dimensional image. The controller and the doctor controlling the system would be in a location that is shielded from radiation of the x-ray source.
The CT scanning system first scans a low-dose scan of the general area of interest of the patient's body and a three-dimensional model or image is generated by the CPU. Using the image and an input device, the doctor defines a region-of-interest, within the patient's body. Once the region-of-interest is defined, the source and detector are then activated to produce a plurality of images of the region-of-interest.
If it is assumed that the areas of the patient's body outside the region-of-interest are not going to change during the procedure, then it is sufficient to use the data gathered during the initial, low-dose scan for the areas of the patient's body surrounding the region-of-interest, to update the original model. Only limited field-of-view scans are needed to update the region-of-interest image. Additionally, the x-ray source is a cone-beam x-ray source to easier to keep the needle within the image during the region-of-interest scan. Thus, the patient's body receives a lower dose of radiation than would otherwise be applied.
The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawing in which:
The system 20 further includes a surgical robot 40 for inserting a needle 42 into a patient's body 44 and delivering a drug at a precisely determined location in the patient's body 44 through the needle 42. The robot 40, or a portion of the robot 40, may optionally include a plurality of locators 46. The position of each of the locators 46 is tracked by a tracking system 48 to determine the position and orientation of the robot 40 and needle 42. Suitable tracking systems 48 and locators 46 are known in the field of image-guided surgery. The locators 46 and tracking system 48 are not necessary in the present invention, because the three-dimensional position and orientation of the needle 42 relative to the patient's body 44 is tracked with the CT scanner, but may further aid in the placement of the needle 42 and/or the control of the robot 40.
The source 22, detector 24, surgical robot 40 (
Referring also to
Once the region-of-interest 60 is defined, the source 32 and detector 24 are then activated to produce a plurality of images of the region-of-interest 60 of the patient's body. The c-arm 30 is rotated about the x-axis by computer-controlled motors in the carriage 32 as the source 22 and detector 34 take images sufficient to update the three-dimensional image of the region-of-interest 60 of the patient's body. The doctor initiates the insertion of the needle 42 by the robot 40 into the patient's body 44 toward the region-of-interest 60. Within the region-of-interest 60, the doctor controls the insertion of the needle 42 while watching the display 52 continuously update the three-dimensional displayed position and orientation of the needle 42 within the body 44. During the procedure, the doctor can rotate, enlarge or otherwise manipulate the image on the display 52, so that the doctor can monitor, control and adjust the travel of the needle 42 into the body 44.
Referring to
The CT scanning system 21 of the present invention could also be used without the robot 40. The doctor could manually insert the needle 42 (or probe) into the patient's body 44 while monitoring the position and orientation of the needle 42 on the display 52 to ensure that the needle 42 is inserted into precisely the desired location within the patient's body 44.
Alternatively, or as an addition to the updates performed by the CT scanning system (i.e. between CT updates), the locators 46 and tracking system 48 may be used to track the position of the needle 42 relative to the 3-dimensional image of the patient's body 44 created from a CT scan. Similarly, sensors and motors in the robot 40 could provide the information regarding the position of the needle 42 relative to the 3-dimensional image as the needle 42 is inserted.
Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
| Number | Date | Country | |
|---|---|---|---|
| 60508517 | Oct 2003 | US |
