Journal article
The physical separation between the LET associated with the ultimate relative biological effect (RBE) and the maximum LET in a proton or ion beam
- Abstract:
- Purpose: To identify the relative positions of the ultimate RBE, at a LET value of LETU (where the LET-RBE turnover point occurs independently of dose), and of the maximum LET (LETM) for a range of ions from protons to Iron ions. Methods: For a range of relativistic velocities (), the kinetic energies, LET values and ranges for each ion are obtained using SRIM software. For protons and helium ions, the LET changes with are plotted and LETM is compared with LETU. For all the ions studied the residual ranges of particles at LETU and LETM are subtracted to provide the physical separation (S) between LETU and LETM. Results: Graphical methods are used to show the above parameters for protons and helium ions. For all the ions studied, LETU occurs at kinetic energies which are higher than those at LETM, so the ultimate maximal RBE occurs proximal to the Bragg peak for individual particles and not beyond it, as is commonly supposed. The distance S, between LETU and LETM, appears to increase linearly with the atomic charge value Z. Conclusions: For the lighter elements, from protons to carbon ions, S is sufficiently small (less than the tolerance/accuracy of radiation treatments) and so will probably not influence therapeutic decisions or outcomes. For higher Z numbers such as Argon and Iron, larger S values of several centimetres occur, which may have implications not only in any proposed therapeutic beams but also at very low doses encountered in radiation protection where the few cells that are irradiated will typically be traversed by a single particle.
- Publication status:
- Accepted
- Peer review status:
- Peer reviewed
Actions
Authors
- Publisher:
- IOP Publishing
- Journal:
- Biomedical Physics and Engineering Express More from this journal
- Publication date:
- 2020-06-18
- Acceptance date:
- 2020-06-18
- DOI:
- EISSN:
-
2057-1976
- Keywords:
- Pubs id:
-
1113038
- Local pid:
-
pubs:1113038
- Deposit date:
-
2020-06-18
Terms of use
- Copyright holder:
- Bleddyn Jones et al.
- Copyright date:
- 2020
- Rights statement:
- © 2020 The Author(s). Published by IOP Publishing Ltd. As the Version of Record of this article is going to be/has been published on a gold open access basis under a CC BY 3.0 licence, this Accepted Manuscript is available for reuse under a CC BY 3.0 licence immediately. Although reasonable endeavours have been taken to obtain all necessary permissions from third parties to include their copyrighted content within this article, their full citation and copyright line may not be present in this Accepted Manuscript version. Before using any content from this article, please refer to the Version of Record on IOPscience once published for full citation and copyright details, as permission may be required. All third party content is fully copyright protected, and is not published on a gold open access basis under a CC BY licence, unless that is specifically stated in the figure caption in the Version of Record
- Licence:
- CC Attribution (CC BY)
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