S1709
Physics - Dose prediction/calculation, optimisation and applications for particle therapy planning
ESTRO 2026
Range Verifier (tARV) can perform as well in an anthropomorphic phantom as in a homogenous QA phantom1. For brevity, only new aspects of this more challenging test are described below. Material/Methods: The target was a multi-modality anthropomorphic phantom (CIRS) composed primarily of hydrogels, with a GI tract that was partially filled with mineral oil.Methods – TA acquisition 2 Gy was delivered PA (gantry angle 180) to 79 spots in seven energy layers, ranging from 135.6 to 162.8 MeV (Fig. 1). No more than 27 proton pulses were delivered to any spot. Some beamlets grazed rib and air. The tARV was positioned distal to the Bragg peak, nearly in-line with the beam trajectory. Orientation was nearly sagittal, with channels 2 and 5 most inferior and superior, respectively. Acoustic paths from treatment spots to sonar receivers 1-3 were generally clear, whereas paths to receivers 5-6 were frequently obstructed by ribs. Paths to receiver 4 often grazed the rib.
Conclusion: Fully automated IMPT planning for skull base
chordoma generated plans of comparable quality to manual clinical plans, achieving similar target coverage and similar or lower OAR doses without hands-on planning time. Case-specific wish-list adaptations can further enhance plan quality, highlighting the potential of a-posteriori multi-criteria optimization to balance target coverage and serial OAR dose exceedance. Keywords: Chordomas, IMPT, MCO Digital Poster 917 Ultrasound Imaging and Ionoacoustic Range Verification During Delivery of a 2 Gy Proton Liver Plan to an Anthropomorphic Phantom Vikren Sarkar 1 , Anjali Chiravuri 2,3 , Roger Vallejos 4 , Ted Lynch 5 , Sarah K Patch 2,6 1 Radiation Oncology, University of Utay, Salt Lake City, USA. 2 engineering, Acoustic Range Estimates, Chicago, USA. 3 biophysics, DESY, Zeuthen, Germany. 4 engineering, Sun Nuclear Corporation, Norfolk, USA. 5 engineering, Sun Nuclear, Norfolk, USA. 6 Physics, University of Wisconsin-Milwaukee, Milwaukee, USA
Fig. 1. Experimental and model setup. Methods - Analysis Custom scripts automated data export from the treatment planning system (Raystation) and development of a finite element model (COMSOL 6.3)Contours of bone, lipids (fat and oil), other soft tissues (muscle and organs), and air were exported as .stl files. The planning CT and individual beamlet dose maps were exported in DICOM format. Exported contours defined the computational domain. To position the tARV, a 2D ultrasound image acquired immediately before delivery was co-registered within the CT volume using manually placed fiducials (3D Slicer, Fig. 2). Range estimates were then computed1, on averaged thermoacoustic pulses with SNR>20 dB and peak-to-peak amplitude exceeding 1 mV.
Purpose/Objective: Determine whether a user-friendly thermoAcoustic
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