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Measurement of the effect of inhomogeneities and compensating bolus in clinical pion beams
Author(s) -
Hogstrom K. R.,
Smith A. R.,
Somers J. W.,
Lane R. G.,
Rosen I. I.,
Simon S. L.,
Kelsey C. A.
Publication year - 1979
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 - 10.1118/1.594548
Subject(s) - pion , bolus (digestion) , physics , nuclear medicine , dosimetry , medical physics , nuclear physics , optics , medicine , radiology , surgery
Measurements of the effects of Teflon and air inhomogeneities on the ionization distributions of clinical negative‐pion beams have been made at the Los Alamos Meson Physics Facility. Inhomogeneity location and pion‐beam energy vary the effect of multiple coulomb scattering on the dose distribution lying in the penumbra of the inhomogeneity. CH 2 bolus adequately corrects for the effects of these inhomogeneities. Bolus misalignment less than 0.5 cm does not seem critical because of large multiple coulomb scattering of the pion beam. However, this and secondary particles emitted from pion stars prevent the pion beam from being precisely shaped with sharp edges, as demonstrated by measurements under a patient bolus.