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SU‐E‐T‐315: In Silico, in Vitro, and in Vivo Quantification of Tungsten and Iodine in Dose Enhanced RT (DERT)
Author(s) -
Nelson G,
Bazalova M,
Chang K,
Ackerman N,
Colomer M Vilalta,
Graves E
Publication year - 2011
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3612266
Subject(s) - in vivo , iodine , nuclear medicine , dosimetry , irradiation , in vitro , chemistry , materials science , medicine , biology , physics , biochemistry , microbiology and biotechnology , organic chemistry , nuclear physics
Purpose: To investigate tungsten nanoparticles (WNP) and conventional iodine contrast as potential vehicles for dose enhancers (DE) for dose enhanced radiation therapy (DERT). Methods: We systematically evaluated DERT in silico, in vitro, and in vivo by quantifying dose enhancement, cell kill, and tumor control. Because of variations in the K‐edge and toxicity of these different nanoparticles we expect to see differences in their viability and effective dose boosting. We used Na[M3‐W3(O2)(OAc)a] as our WNP, and iohexol as our iodine agent. Monte Carlo (MC) simulations using the EGSncr codes were performed to quantify the macroscopic dose enhancement as a function of DE concentration from both DEs. The DEs were used in 7, 15, and 30 mg/ml concentrations in vitro with AA8 CHO cell lines and were irradiated with varying doses using a 150 kV beam to establish cell survival curves. Balb‐c mice were injected with the same cell lines used in vitro to grow as subcutaneous tumors. The tumors were directly injected with the DE formulations and a series of fluoroscopic x‐ray images were acquired to determine the biological half‐life of the DEs in the tumor. Mouse tumors with and without DE were irradiated with a 150 kVp beam and tumor regrowth delay was measured. Results: MC simulations showed macroscopic dose enhancement varying from 1.8 to 3.8 for iodine and from 1.9 to 4.0 for tungsten when irradiated with a 150 kV beam. The tungsten in vitro study indicated dose enhancement of a factor of 2.2 for a concentration of 30 mg/mL. The biological half‐life of tungsten in the tumor injected with 200 mg/mL was shown to be 20 minutes. Conclusion: Preliminary in silico, in vitro, and in vivo studies of tungsten nanoparticles and iodine contrast showed the potential for their use in dose enhanced radiation therapy.