Modelling the Iono-Acoustic Wave Field for Proton Beam Range Verification

Modelling the Iono-Acoustic Wave Field for Proton Beam Range Verification

van Dongen, K.W.A. (TU Delft ImPhys/Acoustical Wavefield Imaging)
de Blécourt, Anne (Student TU Delft)
Lens, E. (TU Delft RST/Medical Physics & Technology)
Schaart, D.R. (TU Delft RST/Medical Physics & Technology)
Vos, F.M. (TU Delft ImPhys/Quantitative Imaging)

2018

In proton therapy, cancer patients are irradiated with high energy protons. For a successful treatment it is important that the location with the highest energy deposition, the so-called Bragg-peak, is located inside the tumor and not in the healthy surrounding tissue. Here, we investigate if the iono-acoustic wave field generated by the protons can be used to monitor the Bragg-peak location during treatment. To this end we present a new numerical method to model the pressure field generated by a clinical proton pencil beam. To compute the field, we convolve a 3-D Greens function, representing the impulse response of the medium, with a volume density of injection rate source. This source describes the expansion of the medium due to a local temperature increase caused by the energy deposited by the protons. To image the proton dose distribution, we first measure the pressure field synthetically by a matrix transducer positioned below the Bragg peak in a plane parallel to the beam. Next, we use these measurements to solve the linear inverse problem iteratively. To regularize the inversion, we take the temporal behavior of the dose deposition as prior knowledge. For the presented example, where the pencil beam has a proton range of 63 mm we are able to reconstruct the location of the Bragg peak within 4 mm accuracy.

iono-acoustics
bragg peak localization
imgaging

http://resolver.tudelft.nl/uuid:3b595caa-c105-4f17-b4f1-a850114ffb4c

https://doi.org/10.1109/ULTSYM.2018.8579869

IEEE

2019-06-20

978-1-5386-3425-7

2018 IEEE International Ultrasonics Symposium (IUS)

2018 IEEE International Ultrasonics Symposium, IUS 2018, 2018-10-22 → 2018-10-25, Portopia Hotel, Kobe, Japan

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

conference paper

© 2018 K.W.A. van Dongen, Anne de Blécourt, E. Lens, D.R. Schaart, F.M. Vos