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Proceedings Paper

Development and clinical application of a patient-position monitoring system
Author(s): Lee H. Gerig; Sabry F. El-Hakim; Janos Szanto; Doug Salhani; A. Girard
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Paper Abstract

We have developed and clinically tested a computer vision system capable of real time monitoring of the position of an oncology (cancer) patient undergoing radiation therapy. The system is able to report variations in patient setup from day to day, as well as patient motion during an individual treatment. The system consists of two CCD cameras mounted in the treatment room and focused on the treatment unit isocenter. The cameras are interfaced to a PC via a two channel video board. Special targets, placed on the patient surface are automatically recognized and extracted by our 3D vision software. The three coordinates of each target are determined using a triangulation algorithm. System accuracy, stability and reproducibility were tested in the laboratory as well as in the radiation therapy room. Beside accuracy, the system must ensure the highest reliability and safety in the actual application environment. In this paper we also report on the results of clinical testing performed on a total of 23 patients having various treatment sites and techniques. The system in its present configuration is capable of measuring multiple targets placed on the patient surface during radiation therapy. In the clinical environment the system has an accuracy and repeatability of better than 0.5 mm in Cartesian space over extended periods (> 1 month). The system can measure and report patient position in less than 5 seconds. Clinically we have found that the system can easily and accurately detect patient motion during treatment as well as variations in patient setup from day to day. A brief description of the system and detailed analysis of its performance in the laboratory and in the clinic are presented.

Paper Details

Date Published: 6 October 1994
PDF: 14 pages
Proc. SPIE 2350, Videometrics III, (6 October 1994); doi: 10.1117/12.189154
Show Author Affiliations
Lee H. Gerig, Ottawa Regional Cancer Ctr. (Canada)
Sabry F. El-Hakim, National Research Council of Canada (Canada)
Janos Szanto, Ottawa Regional Cancer Ctr. (Canada)
Doug Salhani, Ottawa Regional Cancer Ctr. (Canada)
A. Girard, Ottawa Regional Cancer Ctr. (Canada)

Published in SPIE Proceedings Vol. 2350:
Videometrics III
Sabry F. El-Hakim, Editor(s)

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