ESTRO 2023 - Abstract Book

S1461

Digital Posters

ESTRO 2023

Conclusion the obtained time-resolved beam evaluation highlights the minimum time/MU required to achieve flatness and symmetry constancy. Such values should be employed during the planning and optimization processes, also considering online plan adaptation and the need for such information in the system TPS.

PO-1740 Monte-Carlo benchmarked quantitative comparison of different dosimeters for ZAP-X characterisation

C. Souto 1,2 , M. Pires 3 , V. Dias 1 , A. Perez-Rozos 4 , C. Huertas 5 , C. Ferrer 5 , C. Marcelino 1 , M. Feijoo 6 , M. Alber 7 , C. Rodrigues 1

1 Mercurius Health, Mercurius Health, Porto Salvo, Portugal; 2 Mercurius Health, Mercurius Health, Porto Salvo - Portugal, Portugal; 3 ZAP-X, ZAP-X, Palo Alto, USA; 4 Servicio Andaluz de Salud, Servicio Andaluz de Salud, Sevilla, Spain; 5 Hospital Universitario La Paz, Hospital Universitario La Paz, Madrid, Spain; 6 BluePhysics, BluePhysics, Tampa, Florida, USA; 7 Scientific RT GmbH, Scientific RT GmbH, Munich, Germany Purpose or Objective To evaluate the congruence of detectors response for base data measurements for the ZAP-X system (ZAP Surgical Systems, San Carlos, USA) benchmarked against corresponding Monte Carlo (MC) synthetic data (Scientific RT GmbH, Munich, D). Materials and Methods All data were acquired in a water tank MP3-XS (PTW, Freiburg, Germany), using a microSilicon PTW60023 (mS60023), a micro diamond PTW60019 (mD60019), ionisation chambers PTW31010 & PTW31021 (IC31010 & IC31021), a plastic scintillation detector (PSD) (Blue Physics LLC, Tampa, USA) and EBT-XD Gafchromic film (Ashland, Covington, USA) At SSD 450mm and 30mm depth, output factors (OF) and cross-profiles were acquired for all collimators s (25, 20, 15, 12.5, 10, 7.5, 5, 4mm) with the mS60023, mD60019, IC31021, EBT-XD and PSD, while depth-dose-curves (DDC) were measured with the mS60023, mD60019, PSD and, only for the collimator of 25mm, with the IC31021. Results Agreement between MC synthetic data and all cross-profiles was well within 2%/0.2mm after tuning the nominal collimator diameters in the range of 0.1-0.2 mm. Similarly, a MC match with the DDC IC31021 data for the collimator 25mm could be achieved if the nominal 3MV spectrum is shifted to a max energy of 3,7MV. OF measurements indicate that the PSD is closest to the MC calculated data and that all the detectors would require correction factors to account for their field- effects (uo to 5%,). If the nominal energy is increased to 3,7MV we observe that no correction factor would have to be applied for the OFs, as for the solid state detectors the oversensitivity tends to be compensated by partial volume effects.

Conclusion