Research Of Radiation Field Visualization Based On Delaunay Triangulation

At present,nuclear technology is being used more and more widely in the medical field,such as radionuclide imaging and internal radiation therapy techniques..However,during diagnosis and treatment for radioisotope may cause additional radiation exposure and harm to other patients,their families,and especially to medical personnel.The application of visualization techniques to radiation protection will enable medical personnel to better understand the distribution of radiation fields and reduce radiation risks.Common radiation field visualization methods are divided into two categories: forward and inverse reduction methods.Forward reduction methods,such as Monte Carlo and point nucleus integration,are not suitable for environments such as nuclear medicine where information on the location and activity of radioactive sources is unknown;common inverse reduction methods are interpolation algorithms,which are computationally intensive and do not fit well with the characteristics of the radiation field.In this paper,the Delaunay triangulation method of two-dimensional interpolation method is combined with the radiation dose dominant structure reduction theory in mathematical construction method,proposed the " Delaunay triangulation + structural reduction" method(hereinafter referred to as the "D&SR method"),which is consistent with the characteristics of the radiation field,to achieve visualization of radiation fields in nuclear medicine by inverting the dose distribution of radiation fields in nuclear medicine with a small amount of sampling data.The main content and results of this paper are as follows.(1)A model of the nuclear medicine department room was built using the Monte Carlo simulation software Geant4,and the room was set up with 4 Radiation source and 77 Na I(Tl)detectors with dimensions ?76.2 mm × 76.2 mm.The angular response values of the Na I(Tl)detector full-energy peak counting rate were scaled by Geant4,and converted the energy spectra measured by the 77 Na I(Tl)detectors to the total air-absorbed dose rate at that position using the full-energy spectrum method to obtain 77 sampling points.(2)In this paper,the Delaunay triangular division method and the theory of radiation dose dominant construction reduction are investigated.Point-by-Point Insertion is chosen as the method for structuring Delaunay triangulation cross multiplication is selected as the method to determine the position of insertion point in Delaunay triangulation.The traditional radiation dose dominant structure reduction theory is optimized for application to Delaunay triangulation.(3)The radiation field was reconstructed using data from 16 out of 77 sampling points by the "D&SR method" and the Kriging interpolation method,respectively.Comparing the data from 61 sampling points with the reconstructed data at the same coordinates,the average relative error of the "D&SR method" is 6.37%,with a maximum relative error of 9.21%;the average relative error of the Kriging interpolation method is 16.31%,with the maximum relative error is 28.33%.The visualization result shows that the "D&SR method" is more accurate for the inversion of the radiation field.