A needle positioning system for percutaneous procedures

[摘要] ENGLISH ABSTRACT: In percutaneous procedures, where the surgeon inserts a needle into a target inthe patient, it is challenging to access the target at therst attempt. Repeatedneedle insertion attempts are highly undesirable, as they lead to increasedtheatre time, patient haemorrhage and radiation exposure. The proposal ofthis thesis was to develop a low-cost system to aid surgeons with the process ofpositioning and orientating the needle prior to insertion. The proposed systemuses a stereo pair of images produced by a standard C-armuoroscope. Byapplying computer vision techniques, such as triangulation, the desired needleposition and orientation are determined from the set of images. An articulatedmanipulator is used to position and orientate the needle. The surgeon makesselections on the images, via a graphical user interface (GUI), to indicate thedesired position and orientation of the needle. Following these selections, analgorithm determines the necessary angles for the manipulator. The surgeonthen positions the manipulator accordingly.Results from tests on a phantom showed the system to be repeatable andaccurate to 2 mm. This is less accurate than similar, existing systems which,reported accuracies of 0:25 and 1:21 mm. However, 2 mm accuracy is consideredadequate as it allows a range of percutaneous procedures to be performedsuch as needle biopsy, regional anaesthesia, brachytherapy and percutaneousnephrolithotomy (PCNL). Tests on both a phantom kidney and a porcine kidneyindicated that the system can function in a real percutaneous procedureand with an anatomical target. The total cost to develop the prototype systemwas R15 000.The accuracy of the proposed system and the time to gain access to the targetindicate that the system can be a bene cial aid to surgeons when performing percutaneous procedures. As minimal X-ray imaging is required, patientswill also be spared excessive radiation exposure and theatre time.

[发布机构] Stellenbosch University