An interpretation of some biological results obtained in range-modulated negative pion beams

D. J. Brenner, John F Dicello, M. Zaider

Research output: Contribution to journalArticle

Abstract

Recent biological data show little change in relative biological effectiveness (RBE) across the peak region of range-modulated pion beams in contrast to previous works which showed increasing RBE with depth. These biological results are shown to be consistent with each other and with previously measured microdosimetric data. The differences are attributed to differences in the lateral spread of the beams. Large lateral distributions result in an increased dose as a result of neutrons emitted in pion "stars," an effect that is quantified using a high-energy neutron transport code. For a large beam which is of the type used in therapy, the neutron dose is as much as 50% of the total "star" dose and of the high linear energy transfer (LET) dose, this percentage increasing with increasing peak volume. Preliminary measurements are in agreement with the calculated results. The rapid increase in neutron dose with field size should be an important factor in pion treatment planning.

Original languageEnglish (US)
Pages (from-to)121-126
Number of pages6
JournalInternational Journal of Radiation Oncology, Biology, Physics
Volume8
Issue number1
DOIs
Publication statusPublished - 1982
Externally publishedYes

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ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Radiation

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