Earticle

초록

영어

Background: The National Institutes for Quantum and Radiological Science and Technology– National Institute of Radiological Sciences (QST–NIRS) has continuously investigated the undesired radiation exposure in ion beam radiotherapy mainly in carbon-ion radiotherapy (CIRT). This review introduces our investigations on the secondary neutron dose in CIRT with the broad and scanning beam methods. Materials and Methods: The neutron ambient dose equivalents in CIRT are evaluated based on rem meter (WENDI-II) measurements. The out-of-field organ doses assuming prostate cancer and pediatric brain tumor treatments are also evaluated through the Monte Carlo simulation. This evaluation of the out-of-field dose includes contributions from secondary neutrons and secondary charged particles. Results and Discussion: The measurements of the neutron ambient dose equivalents at a 90° angle to the beam axis in CIRT with the broad beam method show that the neutron dose per treatment dose in CIRT is lower than that in proton radiotherapy (PRT). For the scanning beam with the energy scanning technique, the neutron dose per treatment dose in CIRT is lower than that in PRT. Moreover, the out-of-field organ doses in CIRT decreased with distance to the target and are less than the lower bound in intensity-modulated radiotherapy (IMRT) shown in AAPM TG-158 (American Association of Physicists in Medicine Task Group). Conclusion: The evaluation of the out-of-field doses is important from the viewpoint of secondary cancer risk after radiotherapy. Secondary neutrons are the major source in CIRT, especially in the distant area from the target volume. However, the dose level in CIRT is similar or lower than that in PRT and IMRT, even if the contributions from all radiation species are included in the evaluation.

목차

ABSTRACT
Introduction
Materials and Methods
1. Measurement of the Neutron Ambient Dose Equivalent in the CIRT Treatment Room
2. Monte Carlo Calculations of the Out-of-Field Organ Doses in CIRT Assuming Prostate Cancer and Pediatric Brain Tumor Treatments
Results and Discussion
1. Measurement of the Neutron Ambient Dose Equivalent in the CIRT Treatment Room
2. Monte Carlo Calculations of the Out-of-Field Organ Doses in CIRT Assuming Prostate Cancer and Pediatric Brain Tumor Treatments
Conclusion
Conflict of Interest
Author Contribution
References

키워드

저자

• Shunsuke Yonai [ Department of Accelerator and Medical Physics, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan ] Corresponding Author
• Shinnosuke Matsumoto [ Department of Accelerator and Medical Physics, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan ]

참고문헌

발행기관

간행물

표지보기 관심저널 등록

• 간행물명

  방사선방어학회지 [Journal of Radiation Protection and Research]

• 간기

  계간

• pISSN

  2508-1888

• 수록기간

  1976~2026

• 등재여부

  KCI 등재,SCOPUS

• 십진분류

  KDC 559 DDC 629