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Tracking Accuracy of Ultra-Wide Band Radar for a High Contrast Object in the Lung Mimicking Phantom: Preliminary Results

S Han-Oh1*, D Han1 , P Tupin2 , A Di Rienzo2 , J Wong1 , (1) Johns Hopkins University, Baltimore, MD, (2) One Health Group, LLC, Chantilly, VA


(Tuesday, 7/16/2019) 10:00 AM - 10:30 AM

Room: Exhibit Hall | Forum 5

Purpose: We investigate the potential of using ultra-wide band (UWB) radar as a real-time and non-ionizing localization device for radiotherapy. Our previous results demonstrated that the UWB can penetrate through the lung mimicking medium to detect a high contrast object. Here, we quantify the tracking accuracy of UWB for a moving target.

Methods: The UWB radar operating from 3.1 to 5.3 GHz was connected to a pair of elliptical antennas. The total transmitting power was 0.7 dBm. The antennas were placed under the plastic tank filled with isopropyl to mimic the permittivity of inflated lung. The tracking target was a 3 cm x 3 cm aluminum plate, as a high contrast object, immersed in isopropyl at distances of 2 cm, 3 cm, and 4 cm from the antennas. The plate was cycled in an one-dimensional sinusoidal motion along the radar’s line of sight with a period of 4 seconds and excursions of 2 cm and 3 cm. In-phase and quadrature demodulation algorithm was used to extract the cyclical motion from the measured radar signal. The temporal tracking resolution of the UWB radar was equivalent to a spatial resolution of 2 mm. The tracking accuracy was quantified as an average absolute difference against the programmed motion.

Results: The tracking accuracy for the 2-cm excursion was 2.5 ± 2.1 mm, 3.4 ± 2.7 mm, and 3.4 ± 2.4 mm at 2-cm, 3-cm, and 4-cm depth, respectively. For the 3-cm motion, 3.0 ± 2.5 mm, 3.5 ± 2.9 mm, and 3.4 ± 2.6 mm for 2-cm, 3-cm, and 4-cm depth, respectively.

Conclusion: With our present system, we demonstrated that UWB radar can track a moving target with 3.2 mm accuracy on average. Our future work will increase the radar power to enable deeper penetration and improve tracking accuracy in various attenuating medium.

Funding Support, Disclosures, and Conflict of Interest: The research project is supported by Allegheny Health Network-Johns Hopkins Cancer Research Fund.


Target Localization, Image-guided Therapy, Nonionizing Radiation


TH- RT Interfraction motion management : Development (new technology and techniques)

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