Abstract:
:Heavy-ion radiotherapy exploits the high biological effectiveness of localized energy deposition delivered by so-called Bragg-peak particles. Recent publications have challenged the established procedures to calculate biological effective dose distributions in treatment planning. They emphasize the importance of very low energy (<500 keV amu(-1)) ions, either as primary particles or originating from molecular and nuclear fragmentations. We show, however, that slow heavy ions with energies below 500 keV amu(-1) only play a negligible role in cancer treatments for several reasons. Their residual range is very small compared to the relevant length scale of treatment planning. Moreover, their relative frequency and also their relative dose distribution are insignificant, since energy loss and range straggling in ion slowing down processes as well as the necessary superposition of Bragg peaks wash out small-scale special effects. Additionally, we show that even a 1000 times larger biological damage of such slow ions would not result in a clinically relevant increase of the photon-equivalent dose. Therefore, neither a more precise physical description of ions in the very distal part of the Bragg peak nor the consideration of radiation damage induced by hyperthermal ions would result in a meaningful improvement of current models for heavy-ion treatment planning.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Elsässer T,Gemmel A,Scholz M,Schardt D,Krämer Mdoi
10.1088/0031-9155/54/7/N03subject
Has Abstractpub_date
2009-04-07 00:00:00pages
N101-6issue
7eissn
0031-9155issn
1361-6560pii
S0031-9155(09)03414-9journal_volume
54pub_type
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