Nuclear Techniques ›› 2020, Vol. 43 ›› Issue (4): 40202-040202.doi: 10.11889/j.0253-3219.2020.hjs.43.040202

• ACCELERATOR, RAY TECHNOLOGY AND APPLICATIONS • Previous Articles     Next Articles

Simulation study on scattering interference in 60Co dual-projection radiation imaging system based on Monte Carlo method

Minzi NI1,2,Zhentao WANG1,2,Peng CONG1,2,Litao LI1,2()   

  1. 1.Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
    2.Beijing Key Laboratory on Nuclear Detection & Measurement Technology, Beijing 100084, China
  • Received:2019-12-31 Revised:2020-02-21 Online:2020-04-15 Published:2020-04-20
  • Contact: Litao LI E-mail:lilitao@mail.tsinghua.edu.cn
  • About author:NI Minzi, female, born in 1995, graduated from Nanjing University of Aeronautics and Astronautics in 2017, master student, focusing on scattering problems in industrial radiation imaging systems
  • Supported by:
    Nuclear Energy Development Project for ‘The 13th Five-Year Plan’(20154602098)

Abstract: Background

In 60Co dual projection radiation imaging system, the radiation sources are arranged at the bottom and side while their corresponding ionization chamber detectors are set respectively in the gantry. With the synchronous movement of the sources and the gantry, the system can obtain both side-view and upward-view images of the objects simultaneously. However, due to the presence of scatter, the imaging of the two projection planes will interfere with each other.

Purpose

This study aims to reduce the effect of scattering between two projection planes and improve the imaging quality of the system by using Monte Carlo method.

Methods

Firstly, a simulation model based on Monte Carlo method was established, and its reliability was verified by comparing the simulation data with the experimental data of the scattering distribution at no-load. Secondly, the scattering effects of different projection plane spacings, different shielding materials (tungsten, lead, steel, and aluminum) around the detector with different installation positions, and thickness of the shielding layer on the scatter were calculated based on the model built. Finally, shielding correction effect of 2.5 cm thick lead layer was evaluated.

Results

Simulation results show that when the projection plane spacing is 40 cm and 80 cm, the scattering can be reduced to less than 55% and 40% of that of the 10 cm plane spacing respectively. When projection plane spacing is 40 cm, a lead shield placed between the gantry support and the side-view ionization chambers can achieve best shielding effect at the same thickness compared with steel and aluminum. When the thickness of the lead is 2.5 cm, scattering will be further reduced by 80%.

Conclusions

This study provides a reference and guidance for the hardware improvement and upgrade of the dual-projection system for scattering correction.

Key words: 60Co dual-projection radiation imaging system, Monte Carlo, Scattering distribution, Hardware correction

CLC Number: 

  • TL99