Substantial dose reduction in modern multi-slice spiral computed tomography (MSCT)-guided craniofacial and skull base surgery.
ABSTRACT Reduction of the radiation exposure involved in image-guided craniofacial and skull base surgery is an important goal. The purpose was to evaluate the influence of low-dose protocols in modern multi-slice spiral computed tomography (MSCT) on target registration errors (TREs).
An anthropomorphic skull phantom with target markers at the craniofacial bone and the anterior skull base was scanned in Sensation Open (40-slice), LightSpeed VCT (64-slice) and Definition Flash (128-slice). Identical baseline protocols (BP) at 120 kV/100 mAs were compared to the following low-dose protocols (LD) in care dose/dose modulation: (LD-I) 100 kV/35ref. mAs, (LD-II) 80 kV/40 - 41ref. mAs, and (LD-III) 80 kV/15 - 17ref. mAs. CTDIvol and DLP were obtained. TREs using an optical navigation system were calculated for all scanners and protocols. Results were statistically analyzed in SPSS and compared for significant differences (p ≤ 0.05).
CTDIvol for the Sensation Open/LightSpeed VCT/Definition Flash showed: (BP) 22.24 /32.48 /14.32 mGy; (LD-I) 4.61 /3.52 /1.62 mGy; (LD-II) 3.15 /2.01 /0.87 mGy; and (LD-III) na/0.76 /0.76 mGy. Differences between the BfS (Bundesamt für Strahlenschutz) reference CTDIvol of 9 mGy and the lowest CTDIvol were approximately 3-fold for Sensation Open, and 12-fold for the LightSpeed VCT and Definition Flash. A total of 33 registrations and 297 TRE measurements were performed. In all MSCT scanners, the TREs did not significantly differ between the low-dose and the baseline protocols.
Low-dose protocols in modern MSCT provided substantial dose reductions without significant influence on TRE and should be strongly considered in image-guided surgery.
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ABSTRACT: Abstract Background: Minimally invasive ostesynthesis of scaphoid fractures may reduce the risk of fracture non-union and shorten the duration of illness. The aim of this study was to analyze the technical feasibility and targeting accuracy of computed tomography (CT) - guided stereotactic Kirschner (K)-wire positioning in the scaphoid. Methods: Nineteen Formalin preserved cadaveric upper extremities (10 right, 9 left) were fixed in 90 degree dorsal extension for percutaneous access from palmar. An ideal central position of the K-wire was planned on the computer adapted from intraoperative CT data. A 3D navigation system and stereotactic targeting device were used for K-wire placement. Target positioning errors were evaluated by fusion of the control CT with the K-wire in place with the planning CT. Results: The procedure allowed for an easy and rigid wrist fixation. K-wire placement showed mean ± SD lateral targeting errors of 0.9 ± 0.5 mm at the scaphoid bone entry and 1.2 ± 0.7 mm at the K-wire tip. The mean angular error was 1.3° ± 1.1° . Total duration of the intervention ranged between 19 and 23 min. Conclusion: CT-guided stereotactic K-wire placement in scaphoid bones is highly accurate. The technique may guide minimally invasive screw-osteosynthesis of scaphoid fractures.Minimally invasive therapy & allied technologies: MITAT: official journal of the Society for Minimally Invasive Therapy 10/2012; · 1.33 Impact Factor
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ABSTRACT: For computer-guided surgery a static surgical guide is used that transfers the virtual implant position from computerized tomographic data to the surgical site. These guides are produced by computer-aided design/computer-assisted manufacture technology, such as stereolithography, or manually in a dental laboratory (using mechanical positioning devices or drilling machines). With computer-navigated surgery the position of the instruments in the surgical area is constantly displayed on a screen with a three-dimensional image of the patient. In this way, the system allows real-time transfer of the preoperative planning and visual feedback on the screen. A workflow of the different systems is presented in this review.Periodontology 2000 10/2014; 66(1). · 4.01 Impact Factor