Ionizing Radiation Acoustic Imaging for 3D Relative Dosimetry
N Ba Sunbul1*, W Zhang2, D Litzenberg3, I Oraiqat4, B Rosen5, S Clarke6, S Pozzi7, P Carson8, M Matuszak9, I El Naqa10, (1) University of Michigan, Ann Arbor, MI, (2) University of Michigan, Ann Arbor, MI, (3) University of Michigan, Ann Arbor, MI, (4) H. Lee Moffitt Cancer Center & Research Institute, Lutz, FL, (5) University of Michigan, Ann Arbor, MI, (6) University of Michigan, Ann Arbor, ,(7) University of Michigan, Ann Arbor, ,(8) The University of Michigan Health System, Ann Arbor, MI, (9) University of Michigan, Ann Arbor, MI, (10) Moffitt Cancer Center, Tampa, FL
Presentations
WE-C1000-IePD-F4-1 (Wednesday, 7/13/2022) 10:00 AM - 10:30 AM [Eastern Time (GMT-4)]
Exhibit Hall | Forum 4
Purpose: The aim of this study is to demonstrate the feasibility of Ionizing Radiation Acoustic Imaging (iRAI) as a promising noninvasive 3D relative dosimetry tool for radiation therapy.
Methods: Induced acoustic waves following photon irradiations in a gelatin/gel phantoms were performed using a customized 2D array transducer. The measured results were compared with 3D gel dosimetry and simulation results. A full 3D dose distribution in the phantom was extracted from the treatment planning system and converted into an initial pressure source distribution, using the medium-dependent dose-pressure relationship. The MATLAB-based toolbox k-Wave was then used to model the propagation of acoustic waves through the phantom and for reconstructing the resulting 3D image.
Results: The simulated and measured acoustic signal for different beam energies, 6MV FFF and 10MV FFF, reflected the proportionality of the generated acoustic signal to the dose deposited per pulse. IRAI technique has shown the ability to identify the beam edges shift within 3 mm resolution. The ability of iRAI to retrieve the dose distribution at the front edge of the field has shown good reproducibility with a 99.3% or higher gamma passing rate using 3%/3mm among three different trials.The ability of iRAI in treatment plan verification was demonstrated by determining the edges of the field. Additionally, iRAI has retrieved the overall shape of the plan. The highest agreement was for the 90% and 80% isodose lines as they are at the center of the 2D array showing higher detectability.
Conclusion: Various treatment plans, including single field and VMAT were measured and simulated in gelatin/gel phantoms. A simulation workflow was developed for testing the effectiveness of iRAI as a promising 3D relative dosimetry tool and compared with the measured data. iRAI has the potential to be a useful dosimeter for some plan verification applications.
Funding Support, Disclosures, and Conflict of Interest: The Gel dosimeters were provided by Modus Medical, London, Ontario. The authors would like to thank Dr. Kalin Penev for his valuable discussions.
Keywords
3D Dosimetry, X-ray Acoustic Imaging, Gel Dosimeter
Taxonomy
Not Applicable / None Entered.
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