Speaker: Mohammad Peikari
PhD Student, Medical Biophysics, University of Toronto
Graduate Research Assistant at Imaging Research Sunnybrook Research Institute, Toronto, Ontario, Canada
Local Organizer: Ms. Marzieh Golabbakhsh on behalf of Dr. Hosssein Rabbani
Title: Characterization of Ultrasound Elevation Beamwidth Artefacts for Brachytherapy Needle Insertion
Time: Wednesday, September 19, 2012, 13.30-15.00
Location: Associate Chair (Research) Conference Room, 3rd Floor, Building No. 4 (Vice Chancellor for Research and Technology), Isfahan University of Medical Sciences, Isfahan
Abstract:
Ultrasound elevation beamwidth leads to image artefacts and uncertainties in localizing objects (such as a surgical needle) in ultrasound images. The clinical significance of errors caused by elevation beamwidth artefacts and imaging parameters in needle insertion procedures were examined. Beveled prostate brachytherapy needles were inserted through all holes of a grid template under real-time transrectal ultrasound (TRUS) guidance. The needle tip position as indicated by the TRUS image was compared to their observed physical location. A new device was developed to measure the ultrasound elevation beamwidth. Imaging parameters of the TRUS scanner have direct impact on the localization error ranging from 0.5 mm upto 4 mm. The smallest localization error was observed laterally close to the center of the grid template, and axially within the beam’s focal zone. Largest localization error occurs laterally around both sides of the grid template, and axially within the beam’s far field. It was also found that the localization errors vary with both lateral and elevation offsets. It was found that properly adjusting the TRUS imaging settings to lower the ultrasound gain and power effectively minimized the appearance of elevation beamwidth artefacts and in turn reduced the localization errors of the needle tip.