TY - JOUR
T1 - Safety Evaluation of a Long-Lived Tumour-Specific Gadolinium (Gd)-Based Imaging Agent in Proton Therapy
AU - Velten, Christian
AU - Tomé, Wolfgang A.
N1 - Publisher Copyright:
© Published under licence by IOP Publishing Ltd.
PY - 2020/10/16
Y1 - 2020/10/16
N2 - We assessed the dosimetric safety of a potential diapeutic Gadolinium-based contrast agent for diagnostic MR imaging and MR-guided radiotherapy by calculating depth-dependent reactions rates in a spread-out Bragg peak (SOBP) in water. Energy-dependent cross-sections for inelastic proton reactions on Gadolinium were folded with proton energy spectra at depth. Particle transport, dose, and phase space scoring was performed using Geant4-based TOPAS Monte Carlo software. The isotopic Terbium yield at depth was calculated to be between 103 to 105 atoms/mmolnatGd per Gray SOBP dose in a 2.4 cm3 volume. At currently achievable Gadolinium concentrations of 0.2 µmol/cm3 this yields approximately 26 atoms/(cm3 GySOBP), corresponding to less than 1 Bq activity. Additional dose from evaporation neutrons and subsequent capture gammas is on the order of 1 µSv/GySOBP. Thus, use of this long-lived contrast agent is dosimetrically safe at current concentrations and induced radioactivity is negligible.
AB - We assessed the dosimetric safety of a potential diapeutic Gadolinium-based contrast agent for diagnostic MR imaging and MR-guided radiotherapy by calculating depth-dependent reactions rates in a spread-out Bragg peak (SOBP) in water. Energy-dependent cross-sections for inelastic proton reactions on Gadolinium were folded with proton energy spectra at depth. Particle transport, dose, and phase space scoring was performed using Geant4-based TOPAS Monte Carlo software. The isotopic Terbium yield at depth was calculated to be between 103 to 105 atoms/mmolnatGd per Gray SOBP dose in a 2.4 cm3 volume. At currently achievable Gadolinium concentrations of 0.2 µmol/cm3 this yields approximately 26 atoms/(cm3 GySOBP), corresponding to less than 1 Bq activity. Additional dose from evaporation neutrons and subsequent capture gammas is on the order of 1 µSv/GySOBP. Thus, use of this long-lived contrast agent is dosimetrically safe at current concentrations and induced radioactivity is negligible.
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U2 - 10.1088/1742-6596/1662/1/012033
DO - 10.1088/1742-6596/1662/1/012033
M3 - Conference article
AN - SCOPUS:85096356095
SN - 1742-6588
VL - 1662
JO - Journal of Physics: Conference Series
JF - Journal of Physics: Conference Series
IS - 1
M1 - 012033
T2 - 20th Biannual Micro-Mini and Nano Dosimetry and Innovative Technologies in Radiation Oncology, MMND ITRO 2020
Y2 - 10 February 2020 through 16 February 2020
ER -