ABSTRACT
@#<b>Objective</b> To discuss the shielding calculation method for proton therapy room, and to provide a scientific basis for shielding design of proton therapy room and improvement of existing national standards. <b>Methods</b> Using the calculation formula and key characteristic parameters from national standards and Chinese and foreign literature, combining with the FLUKA Monte Carlo method, empirical formula calculation and Monte Carlo simulation were conducted for the neutron ambient dose equivalent rates of the focuses outside the shielding of proton therapy room. The estimation results of the two methods were analyzed. <b>Results</b> Relative to the calculation results of the single exponential formula in the two directions of 0° and 50° in the beam loss point of divergence slit (0.13 and 12.4), the calculation results of the double exponential formula (0.40 and 17.9) were more consistent with the Monte Carlo simulation results (0.32 ± 0.19 and 18.2 ± 4.98). The Monte Carlo simulation results of copper target and nickel target were similar, suggesting that the key characteristic parameters of concrete shielding for copper target could be well applied to the calculation of nickel target, but the neutron ambient dose equivalent rates were underestimated when applied to tantalum target, with a difference of 5.7 times and 1.3 times in the two directions of 0° and 40°, respectively. <b>Conclusion</b> The dose rate estimates based on the calculation formula and key characteristic parameters from Chinese and foreign literature are consistent with FLUKA simulation results, and this method can be used in the shielding design of proton therapy room as a supplement and improvement to the existing national standards.
ABSTRACT
Uno de los requerimientos indispensables en el diseño de las instalaciones donde se trabaja con radiación ionizante es la determinación del espesor adecuado de las paredes, pisos, techo y puertas de los locales, que garanticen dosis por debajo de las restricciones establecidas por la autoridad regulatoria. El objetivo del presente trabajo es desarrollar una herramienta interactiva, libre y de código abierto para calcular los blindajes requeridos en una instalación de Medicina Nuclear. En el código, desarrollado en Phyton utilizando el entorno interactivo Jupiter Notebook, se incluyó el análisis tanto para Tomografía por Emisión de Fotón Único como para Tomografía por Emisión de Positrones. La herramienta fue implementada para el cálculo de los blindajes de un departamento de Medicina Nuclear del Centro Internacional de Restauración Neurológica (CIREN). Esta herramienta libre y de código abierto facilita los cálculos de blindaje aumentando la velocidad, lo que contribuye a lograr una optimización de la protección radiológica, pero también puede usarse como herramienta pedagógica(AU)
One of the indispensable requirements in the design of the facilities where ionizing radiation is used is the determination of the adequate thickness of the walls, floors, ceiling and doors of the premises, which guarantee doses below the restrictions established by the regulatory authority. The goal of this work is to develop an interactive, free and open source tool to calculate the shields required in a Nuclear Medicine installation. Analysis for both Single Photon Emission Tomography and Positron Emission Tomography was included in the code, developed in Phyton using the interactive Jupiter Notebook environment. The tool was implemented to calculate the shields of a Nuclear Medicine department of the International Center for Neurological Restoration (CIREN). This free and open source tool facilitates shielding calculations by increasing speed, which contributes to the optimization of radiation protection, but can also be used as a pedagogical tool(AU)
Subject(s)
Humans , Radiation Protection/methods , Building Codes/standards , Shielding against Radiation , Nuclear Medicine Department, Hospital/standardsABSTRACT
Objective To provide a solution to improve the radiation shielding for medical accelerator room with clay bricks.Methods According to the basic shielding equations provided by the relevant national standards and international reports,equations for shielding reconstruction calculation were derived to calculate the required thickness of clay bricks wall,which reached the reference dose rate control level.The dose rates at reference points after reconstruction were also estimated based on the measured dose rates at reference points before reconstruction of accelerator room,calculated distance correction factors and transmission factors of added clay bricks wall.Results The measured dose rates satisfied the requirement of reference dose rate control level.The estimated dose rates were slightly higher than the measured values.Conclusion The radiation shielding requirement of medical accelerator room is fulfilled with the presented shielding reconstruction method by building clay bricks wall,measured dose rates could be conservatively predicted with the dose rates calculated by derived equations.
ABSTRACT
Objective To provide a solution to improve the radiation shielding for medical accelerator room with clay bricks.Methods According to the basic shielding equations provided by the relevant national standards and international reports,equations for shielding reconstruction calculation were derived to calculate the required thickness of clay bricks wall,which reached the reference dose rate control level.The dose rates at reference points after reconstruction were also estimated based on the measured dose rates at reference points before reconstruction of accelerator room,calculated distance correction factors and transmission factors of added clay bricks wall.Results The measured dose rates satisfied the requirement of reference dose rate control level.The estimated dose rates were slightly higher than the measured values.Conclusion The radiation shielding requirement of medical accelerator room is fulfilled with the presented shielding reconstruction method by building clay bricks wall,measured dose rates could be conservatively predicted with the dose rates calculated by derived equations.
ABSTRACT
Objective To use Monte Carlo method to build a shielding calculation model for the proton and heavy ion treatment room,and to provide a reliable calculation method for shielding design.Methods A Monte Carlo-based FLUKA code was adopted to build the shielding calculation model for the proton and heavy ion treatment room,and to simulate the radiation field distribution in the proton and heavy ion treatment room.The calculation model was verified through the radiation detection around the proton and heavy ions treatment room.Results The FLUKA code-based simulation results were consistent with the radiation detection.Conclusions The shielding calculation model based on FLUKA code can simulate the radiation field from proton and heavy ions.Among the secondary particles,secondary neutrons are the dominant component and the main concern of accelerator shielding design.In shielding calculation,the emphasis should be put on both beam intensity and energy.