Radial Dose, LET, and W for 16 O Ions in N 2 and Tissue-Equivalent Gases

Average energy to produce an ion pair (W), distance restricted, and total linear energy transfer and dose as a function of radial distance D(r) from the ion's path were measured for 41.1-MeV16 O ions in nitrogen and Rossi-type tissue-equivalent gas Results for W were 38.9 ± 0.54 eV/ion pair for nitrogen and 33.4 ± 0.47 eV/ion pair for tissue-equivalent gas. Results for total linear energy transfer ( LET∞ ) were 6507 MeV· cm² g⁻¹ for tissue-equivalent gas and 6210 MeV· cm² g⁻¹ for nitrogen. Results for D(r) were used to calculate similar values to be expected in tissue-like material having a density of 1 g/ cm³ . The range of radial distances covered was from 0.2 to 300 nm in tissue. Results are compared with calculations based on Paretzke's continuous slowing down model. Measured D(r) values in nitrogen were randomly distributed...