Room: Exhibit Hall
Purpose: Carbon-ion-beam radiotherapy is a novel technique to treat cancer patients. Its unique radiobiological properties offer more conformal targeted doses as compared to conventional radiation therapy. However, small errors in calculating its radiobiological quantities could lead to suboptimal conformity. The goal of this study is to investigate the radiobiological properties of carbon-ion-beams in the mediums.
Methods: Carbon-ion-beams of energy ranging from 220 MeV/u to 290 MeV/u were simulated in different mediums using GEANT4 10.4.p01. By adopting a GEANT4-hadron therapy example, absorbed dose distribution along the depth (DD), averaged dose linear energy transfer (LET-dose) and spread-out Bragg peak (SOBP) were calculated as a function of depth through various types of mediums.
Results: The observed depth for Bragg peaks were 9.03 cm, 11.85 cm and 12.25 cm for bone, lung and water, respectively. Similarly, depths for LET-dose were 9.26 cm, 12.19 cm and 12.61 cm for bone, lung and water, respectively. In the stated energy range, the physical Bragg peaks were 7.21 â€“ 11.65 cm, 9.45 â€“ 15.29 cm and 9.77 â€“ 15.85 cm for bone, lung and water, respectively. Spread in LET-dose were 7.47 â€“ 11.95 cm, 9.77 â€“ 15.71 cm and 10.11 â€“ 16.25 cm for bone, lung and water, respectively. The significant dependence of these quantities can be observed for various mediums at different energies. There was an abrupt increase near Bragg peak followed by rapid decrease in LET-dose due to the averaged energy-weighted stopping power. Furthermore, a slight increase as compared to DD in the depths for LET-dose peaks was observed.
Conclusion: With its higher LET, the carbon-ion-beams could achieve more conformal doses and higher cell killing than conventional radiation therapy. A thorough investigation and comprehensive understanding of its radiobiological properties at different mediums will be much needed to better utilize it for the benefits of cancer patients.
Funding Support, Disclosures, and Conflict of Interest: Research reported in this publication was supported by the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health under Award Number R01EB022589. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Not Applicable / None Entered.