Implementation of a Monte Carlo based inverse planning model for clinical IMRT with MCNP code

This paper presents the results of research on photon reflection from plane targets based on Monte Carlo simulations performed by the MCNP code. Five materials (water, concrete, aluminum, iron, and copper) are examined in the area of initial photon energies of up to 200 keV. The values of the total number albedo for photons dependent on the initial photon energy or the mean number of photon scatterings are calculated and graphically presented. We have shown that the values of the total number albedo for different target materials, expressed as a function of the mean number of photon scatterings, are in good agreement with each other and can be approximated by simple, universal analytic functions obtained by the least squares method. The accuracy of these analytic appoximations is confirmed by their comparison with the results of PENELOPE and FOTELP Monte Carlo codes.

Download Full-text

DESAIN KOLIMATOR TIPE TABUNG UNTUK PENYEDIAAN BERKAS RADIOGRAFI DENGAN SUMBER GENERATOR NETRON

GANENDRA Majalah IPTEK Nuklir ◽

10.17146/gnd.2007.10.2.162 ◽

2007 ◽

Vol 10 (2) ◽

Author(s):

Yohannes Sardjono

Keyword(s):

Monte Carlo ◽

Mcnp Code ◽

Beam Filter

DESAIN KOLIMATOR TIPE TABUNG UNTUK PENYEDIAAN BERKAS RADIOGRAFI DENGAN SUMBERGENERATOR NETRON. Telah dilakukan desain kolimator untuk penyediaan berkas radiografi netron dengansumber generator netron. Kolimator ini berguna untuk mendapatkan fluks netron termal yang optimal dengan pengotorradiasi (netron epitermal dan gamma) yang sekecil-kecilnya. Proses desain dilakukan dengan melakukan simulasimenggunakan Monte Carlo N-Particle (MCNP) code untuk menghitung tally berupa fluks netron dan laju dosisekuivalen. Desain kolimator yang dipilih adalah jenis tabung yang tersusun dari material moderator parafin, reflektorgrafit, dan kolimator wall alumunium. Parameter optimasi desain adalah panjang kolimator 4 - 8 cm, dengan interval 1cm, jenis bahan moderator (parafin, grafit, berilium, dan air), jenis beam filter adalah timbal, dan material apertureadalah boron atau kadmium. Kriteria penerimaan adalah fluks netron termal 103 - 106 n.cm-2.s-1, n/γ ratio > 106n.cm-2.mR-1 dan Cd ratio > 2. Untuk keselamatan lingkungan digunakan parafin sebagai biological shielding dan timbalsebagai casing. Dari hasil perhitungan optimasi desain dapat diperoleh bahwa kolimator dengan sumber generatornuetron menghasilkan keluaran fluks netron termal 4.67 + 0.5981 x 103 n.cm-2.s-1, rasio netron-gamma (n/γ) ≥ (1.56 +0,000111).106 n.cm–2 mR-1 dan laju dosis ekuivalen pada jarak 10 cm dari permukaan fasilitas adalah 0,0378 - 0,0521mR/jam.

Download Full-text

Neutrons along the labyrinth of high energy medical accelerators: Effect of wall materials

HNPS Proceedings ◽

10.12681/hnps.2026 ◽

2019 ◽

Vol 21 ◽

pp. 169

Author(s):

M. Fakinou ◽

I. E. Stamatelatos ◽

J. Kalef-Ezra

Keyword(s):

Monte Carlo ◽

Cost Effective ◽

High Energy ◽

Wall Material ◽

Mcnp Code ◽

Dose Equivalent ◽

Concrete Wall ◽

Ambient Dose Equivalent ◽

Wall Materials ◽

Ambient Dose

Neutron streaming along the labyrinth of a generic bunker of an 18MV medical accelerator was evaluated. Monte Carlo simulations using MCNP code were performed to calculate neutron ambient dose equivalent along the labyrinth. The effect of plain, borated and barites concrete wall material, as well as borated concrete and plywood (Celotex), as neutron absorbing wall liners, was examined. The results of the study suggest that plywood can provide a cost effective material to attenuate neutron streaming along the labyrinth.

Download Full-text