Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: In percutaneous procedures, where the surgeon inserts a needle into a target in
the patient, it is challenging to access the target at the rst attempt. Repeated
needle insertion attempts are highly undesirable, as they lead to increased
theatre time, patient haemorrhage and radiation exposure. The proposal of
this thesis was to develop a low-cost system to aid surgeons with the process of
positioning and orientating the needle prior to insertion. The proposed system
uses a stereo pair of images produced by a standard C-arm uoroscope. By
applying computer vision techniques, such as triangulation, the desired needle
position and orientation are determined from the set of images. An articulated
manipulator is used to position and orientate the needle. The surgeon makes
selections on the images, via a graphical user interface (GUI), to indicate the
desired position and orientation of the needle. Following these selections, an
algorithm determines the necessary angles for the manipulator. The surgeon
then positions the manipulator accordingly.
Results from tests on a phantom showed the system to be repeatable and
accurate 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 considered
adequate as it allows a range of percutaneous procedures to be performed
such as needle biopsy, regional anaesthesia, brachytherapy and percutaneous
nephrolithotomy (PCNL). Tests on both a phantom kidney and a porcine kidney
indicated that the system can function in a real percutaneous procedure
and with an anatomical target. The total cost to develop the prototype system
was R15 000. The accuracy of the proposed system and the time to gain access to the target
indicate that the system can be a bene cial aid to surgeons when performing percutaneous procedures. As minimal X-ray imaging is required, patients
will also be spared excessive radiation exposure and theatre time. / AFRIKAANSE OPSOMMING: In perkutane prosedures, waar die chirurg 'n naald in 'n teiken op die pasiënt
invoeg, is dit moeilik om met die eerste probeerslag toegang tot die teiken
te bekom. Herhaalde pogings om die naald in te voeg is hoogs ongewens,
aangesien dit tot verlengde teatertyd, bloeding by pasinte sowel as stralingsblootstelling
lei. 'n Laekostestelsel is ontwikkel om chirurge by te staan met die
proses om die naald voor invoeging te plaas en te oriënteer. Die stelsel gebruik
'n paar stereobeelde wat deur 'n standaard-C-arm- uoroskoop voortgebring
word. Met behulp van rekenaarsigtegnieke, soos triangulasie, word die gewenste
naaldposisie en -oriëntasie uit die stel beelde bepaal. 'n Geartikuleerde
manipuleerder word gebruik om die naald te plaas en te oriënteer. Die chirurg
voer die vereiste invoerdata deur middel van 'n gra ese gebruikerskoppelvlak
(GGK) in, waarna 'n algoritme die vereiste hoeke vir die manipuleerder bepaal.
Die chirurg plaas dan die manipuleerder dienooreenkomstig.
Die resultate van toetse op 'n fantoom toon dat die stelsel herhaalbaar en
tot op 2 mm akkuraat is. Dit is minder akkuraat as soortgelyke, bestaande
stelsels, wat 'n akkuraatheid van 0:25 mm en 1:21 mm onderskeidelik aangemeld
het. Tog kan akkuraatheid van 2 mm as voldoende beskou word, aangesien
dit 'n verskeidenheid perkutane prosedures moontlik maak, soos naaldbiopsies,
regionale anestesie, bragiterapie en perkutane nefrolitotomie (PCNL). Toetse
op 'n fantoomnier dui daarop dat die stelsel wél in 'n werklike perkutane prosedure
kan funksioneer. Toetse op 'n varknier toon dat die stelsel wél ook met
'n anatomiese teiken kan werk. Die totale koste om die prototipe te ontwikkel
was R15 000.
Die akkuraatheid van die voorgestelde stelsel en die tydsduur om toegang
tot die teiken te bekom, dui daarop dat die stelsel 'n nuttige hulpmiddel kan wees vir chirurge wat perkutane prosedures uitvoer. Aangesien minimale Xstraalbeelding
vereis word, sal dit pasiënte ook oormatige stralingsblootstelling
en verlengde teatertyd spaar.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/71626 |
| Date | 12 1900 |
| Creators | Garth-Davis, Bryan |
| Contributors | Scheffer, C., Schreve, K., Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 101 p. : ill. |
| Rights | Stellenbosch University |
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