A comparative study on dispersed doses during photon and proton radiation therapy in pediatric applications

Abstract

The Monte Carlo method was employed to simulate realistic treatment situations for photon and proton radiation therapy for a set of Oak Ridge National Laboratory (ORNL) pediatric phantoms for 15, 10, 5 and 1-year olds as well as newborns. Complete radiotherapy situations were simulated using the previously developed NRUrad input code for Monte Carlo N-Particle (MCNP) code package. Each pediatric phantom was irradiated at five different positions, namely, the testes, colon, liver, left lung and brain, and the doses in targeted organs (Dt) were determined using the track length estimate of energy. The dispersed photon and proton doses in non-targeted organs (Dd), namely, the skeleton, skin, brain, spine, left and right lungs were computed. The conversion coefficients (F = Dd/Dt) of the dispersed doses were used to study the dose dispersion in different non-targeted organs for phantoms for 15, 10, 5 and 1-year olds as well as newborns. In general, the F values were larger for younger patients. The F values for non-targeted organs for phantoms for 1-year olds and newborns were significantly larger compared to those for other phantoms. The dispersed doses from proton radiation therapy were also found to be significantly lower than those from conventional photon radiation therapy. For example, the largest F values for the brain were 65.6% and 0.206% of the dose delivered to the left lung (P4) for newborns during photon and proton radiation therapy, respectively. The present results demonstrated that dispersion of photons and generated electrons significantly affected the absorbed doses in non-targeted organs during pediatric photon therapy, and illustrated that proton therapy could in general bring benefits for treatment of pediatric cancer patients.

Proton range monitoring using 13N peak for proton therapy applications

“…The obtained results were normalized to the primary incident proton (see Ref. [ 2 ]). The tally results obtained from Monte Carlo simulations are mostly normalized per primary source particle by the Monte Carlo simulation package, as the absolute values would have no physical meaning.…”

“…In this regard, the use of high-energy proton beams has garnered significant attention worldwide [ 1 ] owing to their low lateral scattering, no exit dose, and high dose deposition in the Bragg peak region. Previously, we performed extensive comparisons between photon and proton radiation therapies for pediatric applications [ 2 ] and discovered that proton beams can significantly reduce the off-target dose to healthy organs and cells.…”

MCHP (Monte Carlo + Human Phantom): Platform to facilitate teaching nuclear radiation physics

“…We refer interested readers to the Refs. [1][2][3][4] regarding the modelling and irradiation of the ORNL adult male human phantom. In the present example, the Monte Carlo N-Particle (MCNP) code version 5 was used to simulate the transport and interaction of high energy photons.…”

DynamicMC: An Open-source GUI Program Coupled with MCNP for Modeling Relative Dynamic Movement of Radioactive Source and ORNL Phantom in a 3-dimensional Radiation Field

“…The use of the Monte Carlo (MC) technique for modeling radiation interaction with matter has been found to be valuable, particularly when employing human phantoms to study the interaction of ionizing radiation with organs in the human body ( Hakimabad and Motavalli 2008 ; Park et al 2006 ; Krstic et al 2014 ; Qiu et al 2008 ; Han et al 2006 ; Krstic and Nikezic 2007 ; Krstic and Nikezic 2009 ; Shahmohammadi Beni et al 2021a , 2017 ; Kramer et al 2002 ). Several types of human phantom models were developed with different ranges of complexities and details.…”

“…The mesh-type phantoms were developed by converting voxel phantoms to a high quality mesh format (Kim et al 2018) Previously, Oak Ridge National Laboratory (ORNL) proposed analytical equations to model the human body, and we used these data to generate mathematical phantoms of the human body for the Monte Carlo N-Particle (MCNP) package (Krstic and Nikezic 2007). The developed ORNL phantoms were widely used in studying the interaction of several types of ionizing radiations with the organs in the human body (Shahmohammadi Beni et al 2021a, 2017. In addition, we recently developed the MCHP (Monte Carlo simulations + Human Phantoms) platform to facilitate teaching nuclear radiation physics, mainly to enhance students' understating of the interaction of ionizing radiation with the human body and the importance of shielding in reducing the absorbed dose to vital organs (Shahmohammadi Beni et al 2021b).…”