State-of-the-art silicon carbide diode dosimeters for ultra-high dose-per-pulse radiation at FLASH radiotherapy.

Autor:	Fleta C; Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Bellaterra, Barcelona, Spain., Pellegrini G; Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Bellaterra, Barcelona, Spain., Godignon P; Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Bellaterra, Barcelona, Spain., Rodríguez FG; Departamento de Física de Partículas, Universidade de Santiago de Compostela, Santiago de Compostela, Spain.; Laboratorio de Radiofísica, RIAIDT, Universidade de Santiago de Compostela, Santiago de Compostela, Spain., Paz-Martín J; Departamento de Física de Partículas, Universidade de Santiago de Compostela, Santiago de Compostela, Spain., Kranzer R; PTW-Freiburg (R&D), Freiburg 79115, Germany.; University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University Oldenburg, 26121, Germany., Schüller A; Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany.
Jazyk:	angličtina
Zdroj:	Physics in medicine and biology [Phys Med Biol] 2024 Apr 19; Vol. 69 (9). Date of Electronic Publication: 2024 Apr 19.
DOI:	10.1088/1361-6560/ad37eb
Abstrakt:	Objective. The successful implementation of FLASH radiotherapy in clinical settings, with typical dose rates >40 Gy s -1 , requires accurate real-time dosimetry. Approach. Silicon carbide (SiC) p-n diode dosimeters designed for the stringent requirements of FLASH radiotherapy have been fabricated and characterized in an ultra-high pulse dose rate electron beam. The circular SiC PiN diodes were fabricated at IMB-CNM (CSIC) in 3 μ m epitaxial 4H-SiC. Their characterization was performed in PTB's ultra-high pulse dose rate reference electron beam. The SiC diode was operated without external bias voltage. The linearity of the diode response was investigated up to doses per pulse (DPP) of 11 Gy and pulse durations ranging from 3 to 0.5 μ s. Percentage depth dose measurements were performed in ultra-high dose per pulse conditions. The effect of the total accumulated dose of 20 MeV electrons in the SiC diode sensitivity was evaluated. The temperature dependence of the response of the SiC diode was measured in the range 19 °C-38 °C. The temporal response of the diode was compared to the time-resolved beam current during each electron beam pulse. A diamond prototype detector (flashDiamond) and Alanine measurements were used for reference dosimetry. Main results. The SiC diode response was independent both of DPP and of pulse dose rate up to at least 11 Gy per pulse and 4 MGy s -1 , respectively, with tolerable deviation for relative dosimetry (<3%). When measuring the percentage depth dose under ultra-high dose rate conditions, the SiC diode performed comparably well to the reference flashDiamond. The sensitivity reduction after 100 kGy accumulated dose was <2%. The SiC diode was able to follow the temporal structure of the 20 MeV electron beam even for irregular pulse estructures. The measured temperature coefficient was (-0.079 ± 0.005)%/°C. Significance. The results of this study demonstrate for the first time the suitability of silicon carbide diodes for relative dosimetry in ultra-high dose rate pulsed electron beams up to a DPP of 11 Gy per pulse. (Creative Commons Attribution license.)
Databáze:	MEDLINE
Externí odkaz:	Zobrazit plný text záznamu