Original paper| Volume 60, P22-29, April 2019

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Enhancement of linear energy transfer in gold nanoparticles mediated radiation therapy

Published:March 23, 2019DOI:


      • The observed sensitization of GNPs in MV beams is higher than the simulated DER.
      • The experimentally reported sensitization of GNPs in kV beams is less than the simulated DER.
      • There is an enhancement in Linear Energy Transfer (LET).
      • LET enhancement ratio shows an excellent agreement with the sensitization reported.
      • LETER is a potentially efficacious metric in predicting the biological outcome of GNP.



      The metric dose enhancement ratio (DER) has been widely used to assess the enhancing capability of gold nanoparticles (GNPs). However, there is a large disparity between the observed radiobiological outcome and DER values. A new metric, linear energy transfer enhancement ratio (LETER), is introduced to bridge the gap between theoretical predictions and the experimentally measured sensitization.


      The radiation transport code SCEPTRE is used to examine the efficacy of the proposed new metric. Different clusters of GNPs irradiated with x-ray photons generated at 120 kVp and therapeutic 6 MV photon beams are investigated. For each pattern, two GNPs sizes are examined 50 and 100 nm.


      An enhancement in the linear energy transfer has been observed for both energies. In the case of 120 kVp, LETER is substantially lower than DER; moreover, it decreases with increasing GNP size. On the other hand, the results of 6 MV show that LETER is relatively higher than DER, and it increases with the size of GNP. For the studied energies, LETER is in good agreement with the sensitization reported in the literature.


      The results indicate the merit of LETER as a better indicator of the radiobiological outcome of GNP aided radiotherapy.


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