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- Titel:
Experimental demonstration of accurate Bragg peak localization with ionoacoustic tandem phase detection (iTPD).
- Dokumenttyp:
- Zeitschriftenaufsatz
- Autor(en):
- Wieser, H P; Huang, Y; Schauer, J; Lascaud, J; Würl, M; Lehrack, S; Radonic, D; Vidal, M; Hérault, J; Chmyrov, A; Ntziachristos, V; Assmann, W; Parodi, K; Dollinger, G
- Abstract:
- Accurate knowledge of the exact stopping location of ions inside the patient would allow full exploitation of their ballistic properties for patient treatment. The localized energy deposition of a pulsed particle beam induces a rapid temperature increase of the irradiated volume and leads to the emission of ionoacoustic (IA) waves. Detecting the time-of-flight (ToF) of the IA wave allows inferring information on the Bragg peak location and can henceforth be used forin-vivorange verification. A challenge for IA is the poor signal-to-noise ratio at clinically relevant doses and viable machines. We present a frequency-based measurement technique, labeled as ionoacoustic tandem phase detection (iTPD) utilizing lock-in amplifiers. The phase shift of the IA signal to a reference signal is measured to derive theToF. Experimental IA measurements with a 3.5 MHz lead zirconate titanate (PZT) transducer and lock-in amplifiers were performed in water using 22 MeV proton bursts. A digital iTPD was performedin-silicoat clinical dose levels on experimental data obtained from a clinical facility and secondly, on simulations emulating a heterogeneous geometry. For the experimental setup using 22 MeV protons, a localization accuracy and precision obtained through iTPD deviates from a time-based reference analysis by less than 15μm. Several methodological aspects were investigated experimentally in systematic manner. Lastly, iTPD was evaluatedin-silicofor clinical beam energies indicating that iTPD is in reach of sub-mm accuracy for fractionated doses < 5 Gy. iTPD can be used to accurately measure theToFof IA signals online via its phase shift in frequency domain. An application of iTPD to the clinical scenario using a single pulsed beam is feasible but requires further development to reach <1 Gy detection capabilities.
- Zeitschriftentitel:
- Physics in Medicine & Biology
- Zeitschriftentitel:
- Phys Med Biol
- Jahr:
- 2021
- Band / Volume:
- 66
- Heft / Issue:
- 24
- Volltext / DOI:
- doi:10.1088/1361-6560/ac3ead
- PubMed:
- http://view.ncbi.nlm.nih.gov/pubmed/34847532
- WWW:
- https://iopscience.iop.org/article/10.1088/1361-6560/ac3ead
- Print-ISSN:
- 0031-9155
- TUM Einrichtung:
- Lehrstuhl für Biologische Bildgebung - Zusammenarbeit mit dem Helmholtz-Zentrum München (Prof. Ntziachristos)
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