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Oblique needle segmentation and tracking for 3D TRUS guided prostate brachytherapy

2005; Wiley; Volume: 32; Issue: 9 Linguagem: Inglês

10.1118/1.2011108

2473-4209

Zhouping Wei, Lori Gardi, Dónal B. Downey, Aaron Fenster,

Prostate Cancer Diagnosis and Treatment

An algorithm was developed in order to segment and track brachytherapy needles inserted along oblique trajectories. Three‐dimensional (3D) transrectal ultrasound (TRUS) images of the rigid rod simulating the needle inserted into the tissue‐mimicking agar and chicken breast phantoms were obtained to test the accuracy of the algorithm under ideal conditions. Because the robot possesses high positioning and angulation accuracies, we used the robot as a “gold standard,” and compared the results of algorithm segmentation to the values measured by the robot. Our testing results showed that the accuracy of the needle segmentation algorithm depends on the needle insertion distance into the 3D TRUS image and the angulations with respect to the TRUS transducer, e.g., at a 10° insertion anglulation in agar phantoms, the error of the algorithm in determining the needle tip position was less than when the insertion distance was greater than . Near real‐time needle tracking was achieved by scanning a small volume containing the needle. Our tests also showed that, the segmentation time was less than , and the scanning time was less than , when the insertion distance into the 3D TRUS image was less than . In our needle tracking tests in chicken breast phantoms, the errors in determining the needle orientation were less than 2° in robot yaw and 0.7° in robot pitch orientations, for up to 20° needle insertion angles with the TRUS transducer in the horizontal plane when the needle insertion distance was greater than .