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Journal of Medical Imaging • Open Access

In vivo reproducibility of robotic probe placement for a novel ultrasound-guided radiation therapy system
Author(s): Muyinatu A. Lediju Bell; H. Tutkun Sen; Iulian I. Iordachita; Peter Kazanzides; John Wong

Paper Abstract

Ultrasound can provide real-time image guidance of radiation therapy, but the probe-induced tissue deformations cause local deviations from the treatment plan. If placed during treatment planning, the probe causes streak artifacts in required computed tomography (CT) images. To overcome these challenges, we propose robot-assisted placement of an ultrasound probe, followed by replacement with a geometrically identical, CT-compatible model probe. <italic<In vivo</italic< reproducibility was investigated by implanting a canine prostate, liver, and pancreas with three 2.38-mm spherical markers in each organ. The real probe was placed to visualize the markers and subsequently replaced with the model probe. Each probe was automatically removed and returned to the same position or force. Under position control, the median three-dimensional reproducibility of marker positions was 0.6 to 0.7 mm, 0.3 to 0.6 mm, and 1.1 to 1.6 mm in the prostate, liver, and pancreas, respectively. Reproducibility was worse under force control. Probe substitution errors were smallest for the prostate (0.2 to 0.6 mm) and larger for the liver and pancreas (4.1 to 6.3 mm), where force control generally produced larger errors than position control. Results indicate that position control is better than force control for this application, and the robotic approach has potential, particularly for relatively constrained organs and reproducibility errors that are smaller than established treatment margins.

Paper Details

Date Published: 23 July 2014
PDF: 9 pages
J. Med. Img. 1(2) 025001 doi: 10.1117/1.JMI.1.2.025001
Published in: Journal of Medical Imaging Volume 1, Issue 2
Show Author Affiliations
Muyinatu A. Lediju Bell, Johns Hopkins Univ. (United States)
H. Tutkun Sen, Johns Hopkins Univ. (United States)
Iulian I. Iordachita, Johns Hopkins Univ. (United States)
Peter Kazanzides, Johns Hopkins Univ. (United States)
John Wong, Johns Hopkins Univ. (United States)


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