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Meeting Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Latest News
The U.S. Million Person Study of Low-Dose-Rate Health Effects
There is a critical knowledge gap regarding the health consequences of exposure to radiation received gradually over time. While there is a plethora of studies on the risks of adverse outcomes from both acute and high-dose exposures, including the landmark study of atomic bomb survivors, these are not characteristic of the chronic exposure to low-dose radiation encountered in occupational and public settings. In addition, smaller cohorts have limited numbers leading to reduced statistical power.
Yecheng Yu, Ping Tan, Yinjie Lin, Yuying Hu, Huidong Guo, Hao Lei, Zhongqi Zhang, Jiadong Li, Delin Hu
Nuclear Technology | Volume 207 | Number 2 | February 2021 | Pages 299-315
Technical Paper | doi.org/10.1080/00295450.2020.1747839
Articles are hosted by Taylor and Francis Online.
A proton therapy facility based on an isochronous superconducting cyclotron is under constructed at the Proton Therapy Facility of the Huazhong University of Science and Technology. Due to the limitation of minimum energy extracted by the energy selection system in the upstream beamline, a range shifter is installed at the end of the nozzle to further decrease the proton beam energy so that the shallow-seated tumors can be treated. In this paper, the physical structure, energy degradation scheme, and material optimization selection of the range shifter are discussed and analyzed by Monte Carlo simulation software Geant4 and FLUKA. At the same time, the treatment outcome on the energy degradation process and its influence on the synthesis of spread-out Bragg peak (SOBP) in the treatment plan system after the application of the range shifter are analyzed. The results show that by using a high-density polyethylene energy-degrading plate with a thickness of 42.35 mm, combined with two 30-mm copper collimators, the range shifter can achieve a good energy-degradation effect while significantly reducing the beam horizontal penumbra at the edge of the radiation field. At the same time, the addition of the range shifter can reduce the number of the energy level required to form the SOBP and shorten the treatment time, but it will inevitably lead to a slight increase in the longitudinal penumbra.