Hogstrom K R, Smith A R, Somers J W, Lane R G, Rosen I I, Simon S L, Kelsey C A
Med Phys. 1979 Jan-Feb;6(1):26-31. doi: 10.1118/1.594548.
Measurement of the effects of Telfon 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. CH2 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.
在洛斯阿拉莫斯介子物理设施中,已对聚四氟乙烯和空气不均匀性对临床负介子束电离分布的影响进行了测量。不均匀性的位置和介子束能量会改变多次库仑散射对位于不均匀性半影区内剂量分布的影响。CH2推注能充分校正这些不均匀性的影响。由于介子束的多次库仑散射较大,推注错位小于0.5厘米似乎并不关键。然而,这以及介子星发射的次级粒子使得介子束无法精确地形成边缘清晰的形状,患者推注下的测量结果证明了这一点。