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Laser-Guided Needle Positioning in CT-System

IP.com Disclosure Number: IPCOM000202039D
Original Publication Date: 2010-Dec-02
Included in the Prior Art Database: 2010-Dec-02
Document File: 5 page(s) / 589K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

In the field of interventional radiology recently a large number of minimal invasive techniques were applied successfully. Thereby, mostly a needle or trocar is inserted into the body of the patient in order to hit the target lesion or volume which has to be treated. Locating and hitting the target lesion without destroying healthy tissue or damaging sensitive structures is a very cumbersome task. Hence, locating the target lesion and finding the correct needle trajectory is mostly done manually by the physician using image-guided CT-systems (CT: Computer Tomography). The disadvantage of the manual performance is that a large number of needle manipulation and control scans are needed. Furthermore, this method is very time consuming. To overcome these problems, most of the currently used methods for positioning the needle are done under continuous or selective CT-fluoroscopy. This helps the physicians to find the needle entry point and also the target lesion, but causes a high amount of radiation exposure to the patient and also to the physician. For that reason, there are several solutions to guide the needle entry point as well as the needle target area for example by drawing a line of the needle path trajectory with the help of a laser-positioning-system (LPS). A major drawback of current use methods is that there is no direct interaction with the CT-system which hinders a fluent workflow respectively it is very complicated to transfer the planned needle path to the scanner coordinate system.

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Laser-Guided Needle Positioning in CT-System

Idea: Martin Sedlmair, DE-Forchheim; Dr. Michael Grasruck, DE-Forchheim

In the field of interventional radiology recently a large number of minimal invasive techniques were applied successfully. Thereby, mostly a needle or trocar is inserted into the body of the patient in order to hit the target lesion or volume which has to be treated. Locating and hitting the target lesion without destroying healthy tissue or damaging sensitive structures is a very cumbersome task. Hence, locating the target lesion and finding the correct needle trajectory is mostly done manually by the physician using image-guided CT-systems (CT: Computer Tomography). The disadvantage of the manual performance is that a large number of needle manipulation and control scans are needed. Furthermore, this method is very time consuming. To overcome these problems, most of the currently used methods for positioning the needle are done under continuous or selective CT-fluoroscopy. This helps the physicians to find the needle entry point and also the target lesion, but causes a high amount of radiation exposure to the patient and also to the physician. For that reason, there are several solutions to guide the needle entry point as well as the needle target area for example by drawing a line of the needle path trajectory with the help of a laser-positioning-system (LPS). A major drawback of current use methods is that there is no direct interaction with the CT-system which hinders a fluent workflow respectively it is very complicated to transfer the planned needle path to the scanner coordinate system.

In the following it is proposed to implement a laser-positioning-system which is mounted onto the rotating part of the gantry. Thus, the laser is rotating and displays the needle entry point and the planned needle path trajectories. An implementation of the laser on an additional mounting inside the scan field is not possible because of distinct metal artifacts. During the rotating, the laser turns on while reaching its position and turns off elsewhere. Because of the limited rotation time of current systems, the frequency of the laser indication is too slow to be optically pursuable. Since the rotation time of the system cannot be further reduced, because of deficient image quality, it is more suitable to apply for example four lasers which are aligned at every 90° in rotation direction. Thus, the laser pulse frequency can be increased. The coordinates of the appropriate invention succession are directly transferred to the laser-positioning-system and will be used to align the lasers into the planned position. Since both coordinate systems, of the scanner and the LPS, are adapted to each other a time consuming calibration step can be omitted. A calibration has to be performed only on system start-up or overall...