A Monte Carlo track structure simulation code for the full-slowing-down carbon projectiles of energies 1 keV u-1–10 MeV u-1 in water

• The paper presents a new Monte Carlo track structure code (KURBUC_carbon) for simulations of full slowing down carbon projectiles C0–C6+ of energies 1 keV/u–10 MeV/u in water vapour. The code facilitates investigation of spatial resolution effect for scoring track parameters under the Bragg peak of carbon ion beam. Interactions of carbon projectiles and secondary electrons were followed event-by-event down to 1 keV/u cutoff for primary ions, and down to 10 eV for electrons. Electronic interactions and nuclear elastic scattering were taken into account, including charge exchange reactions and double electronic interactions for the carbon projectiles. The reliability of the code was tested for radial dose, range, and W-value. The calculated results were compared with the published experimental data, and other model calculations. The results obtained showed good agreement in most cases where comparisons could be made. Depth dose profiles for 1-10 MeV/u C6+ were used to form an SOBP of 0.35 mm width in water. At all depths of the SOBP, the energy distributions of the carbon projectiles varied appreciably with the change in the scoring volume. The corresponding variation was nearly negligible for the track average LET, except at the distal end of the SOBP. By varying the scoring slab thickness from 1 to 100 µm, the maximum track average LET decreased by ~30%. The Monte Carlo track structure simulation in the full slowing down mode is a powerful tool for investigation of biophysical properties of radiation tracks under the Bragg peak and SOBP of carbon ion beam. For estimation of radiation effectiveness under the Bragg peak the new Monte Carlo track structure code provides yet another accurate and effective dosimetry tool at a single cell level. This is because radiobiology within tissue elements can only be understood with dosimetry at cellular and subcellular level.

Ämnesord

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

NATURVETENSKAP  -- Data- och informationsvetenskap -- Annan data- och informationsvetenskap (hsv//swe)

NATURAL SCIENCES  -- Computer and Information Sciences -- Other Computer and Information Science (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Radiologi och bildbehandling (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Radiology, Nuclear Medicine and Medical Imaging (hsv//eng)

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

Nyckelord

Track structure

Monte Carlo simulations

carbon ions

Bragg peak

SOBP

dosimetry

LET

CTMC

Medical Radiation Physics

medicinsk strålningsfysik

Publikations- och innehållstyp

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