Applicability of self-activation of an NaI scintillator for measurement of photo-neutrons around a high-energy X-ray radiotherapy machine

Genichiro Wakabayashi, Akihiro Nohtomi, Eriko Yahiro, Toshioh Fujibuchi, Junichi Fukunaga, Yoshiyuki Umezu, Yasuhiko Nakamura, Katsumasa Nakamura, Makoto Hosono, Tetsuo Itoh

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The applicability of the activation of an NaI scintillator for neutron monitoring at a clinical linac was investigated experimentally. Thermal neutron fluence rates are derived by measurement of the I-128 activity generated in an NaI scintillator irradiated by neutrons; β-rays from I-128 are detected efficiently by the NaI scintillator. In order to verify the validity of this method for neutron measurement, we irradiated an NaI scintillator at a research reactor, and the neutron fluence rate was estimated. The method was then applied to neutron measurement at a 10-MV linac (Varian Clinac 21EX), and the neutron fluence rate was estimated at the isocenter and at 30 cm from the isocenter. When the scintillator was irradiated directly by high-energy X-rays, the production of I-126 was observed due to photo-nuclear reactions, in addition to the generation of I-128 and Na-24. From the results obtained by these measurements, it was found that the neutron measurement by activation of an NaI scintillator has a great advantage in estimates of a low neutron fluence rate by use of a quick measurement following a short-time irradiation. Also, the future application of this method to quasi real-time monitoring of neutrons during patient treatments at a radiotherapy facility is discussed, as well as the method of evaluation of the neutron dose.

Original languageEnglish
Pages (from-to)125-134
Number of pages10
JournalRadiological physics and technology
Volume8
Issue number1
DOIs
Publication statusPublished - Jan 1 2015

Fingerprint

Neutrons
scintillation counters
radiation therapy
Radiotherapy
X-Rays
activation
neutrons
x rays
fluence
energy
thermal neutrons
nuclear reactions
rays
reactors
Hot Temperature
dosage
irradiation
evaluation

All Science Journal Classification (ASJC) codes

  • Radiation
  • Physical Therapy, Sports Therapy and Rehabilitation
  • Radiology Nuclear Medicine and imaging

Cite this

Applicability of self-activation of an NaI scintillator for measurement of photo-neutrons around a high-energy X-ray radiotherapy machine. / Wakabayashi, Genichiro; Nohtomi, Akihiro; Yahiro, Eriko; Fujibuchi, Toshioh; Fukunaga, Junichi; Umezu, Yoshiyuki; Nakamura, Yasuhiko; Nakamura, Katsumasa; Hosono, Makoto; Itoh, Tetsuo.

In: Radiological physics and technology, Vol. 8, No. 1, 01.01.2015, p. 125-134.

Research output: Contribution to journalArticle

Wakabayashi, Genichiro ; Nohtomi, Akihiro ; Yahiro, Eriko ; Fujibuchi, Toshioh ; Fukunaga, Junichi ; Umezu, Yoshiyuki ; Nakamura, Yasuhiko ; Nakamura, Katsumasa ; Hosono, Makoto ; Itoh, Tetsuo. / Applicability of self-activation of an NaI scintillator for measurement of photo-neutrons around a high-energy X-ray radiotherapy machine. In: Radiological physics and technology. 2015 ; Vol. 8, No. 1. pp. 125-134.
@article{86c9a070b00f4b8ca6e0b45e8d0703dd,
title = "Applicability of self-activation of an NaI scintillator for measurement of photo-neutrons around a high-energy X-ray radiotherapy machine",
abstract = "The applicability of the activation of an NaI scintillator for neutron monitoring at a clinical linac was investigated experimentally. Thermal neutron fluence rates are derived by measurement of the I-128 activity generated in an NaI scintillator irradiated by neutrons; β-rays from I-128 are detected efficiently by the NaI scintillator. In order to verify the validity of this method for neutron measurement, we irradiated an NaI scintillator at a research reactor, and the neutron fluence rate was estimated. The method was then applied to neutron measurement at a 10-MV linac (Varian Clinac 21EX), and the neutron fluence rate was estimated at the isocenter and at 30 cm from the isocenter. When the scintillator was irradiated directly by high-energy X-rays, the production of I-126 was observed due to photo-nuclear reactions, in addition to the generation of I-128 and Na-24. From the results obtained by these measurements, it was found that the neutron measurement by activation of an NaI scintillator has a great advantage in estimates of a low neutron fluence rate by use of a quick measurement following a short-time irradiation. Also, the future application of this method to quasi real-time monitoring of neutrons during patient treatments at a radiotherapy facility is discussed, as well as the method of evaluation of the neutron dose.",
author = "Genichiro Wakabayashi and Akihiro Nohtomi and Eriko Yahiro and Toshioh Fujibuchi and Junichi Fukunaga and Yoshiyuki Umezu and Yasuhiko Nakamura and Katsumasa Nakamura and Makoto Hosono and Tetsuo Itoh",
year = "2015",
month = "1",
day = "1",
doi = "10.1007/s12194-014-0300-3",
language = "English",
volume = "8",
pages = "125--134",
journal = "Radiological Physics and Technology",
issn = "1865-0333",
publisher = "Springer Japan",
number = "1",

}

TY - JOUR

T1 - Applicability of self-activation of an NaI scintillator for measurement of photo-neutrons around a high-energy X-ray radiotherapy machine

AU - Wakabayashi, Genichiro

AU - Nohtomi, Akihiro

AU - Yahiro, Eriko

AU - Fujibuchi, Toshioh

AU - Fukunaga, Junichi

AU - Umezu, Yoshiyuki

AU - Nakamura, Yasuhiko

AU - Nakamura, Katsumasa

AU - Hosono, Makoto

AU - Itoh, Tetsuo

PY - 2015/1/1

Y1 - 2015/1/1

N2 - The applicability of the activation of an NaI scintillator for neutron monitoring at a clinical linac was investigated experimentally. Thermal neutron fluence rates are derived by measurement of the I-128 activity generated in an NaI scintillator irradiated by neutrons; β-rays from I-128 are detected efficiently by the NaI scintillator. In order to verify the validity of this method for neutron measurement, we irradiated an NaI scintillator at a research reactor, and the neutron fluence rate was estimated. The method was then applied to neutron measurement at a 10-MV linac (Varian Clinac 21EX), and the neutron fluence rate was estimated at the isocenter and at 30 cm from the isocenter. When the scintillator was irradiated directly by high-energy X-rays, the production of I-126 was observed due to photo-nuclear reactions, in addition to the generation of I-128 and Na-24. From the results obtained by these measurements, it was found that the neutron measurement by activation of an NaI scintillator has a great advantage in estimates of a low neutron fluence rate by use of a quick measurement following a short-time irradiation. Also, the future application of this method to quasi real-time monitoring of neutrons during patient treatments at a radiotherapy facility is discussed, as well as the method of evaluation of the neutron dose.

AB - The applicability of the activation of an NaI scintillator for neutron monitoring at a clinical linac was investigated experimentally. Thermal neutron fluence rates are derived by measurement of the I-128 activity generated in an NaI scintillator irradiated by neutrons; β-rays from I-128 are detected efficiently by the NaI scintillator. In order to verify the validity of this method for neutron measurement, we irradiated an NaI scintillator at a research reactor, and the neutron fluence rate was estimated. The method was then applied to neutron measurement at a 10-MV linac (Varian Clinac 21EX), and the neutron fluence rate was estimated at the isocenter and at 30 cm from the isocenter. When the scintillator was irradiated directly by high-energy X-rays, the production of I-126 was observed due to photo-nuclear reactions, in addition to the generation of I-128 and Na-24. From the results obtained by these measurements, it was found that the neutron measurement by activation of an NaI scintillator has a great advantage in estimates of a low neutron fluence rate by use of a quick measurement following a short-time irradiation. Also, the future application of this method to quasi real-time monitoring of neutrons during patient treatments at a radiotherapy facility is discussed, as well as the method of evaluation of the neutron dose.

UR - http://www.scopus.com/inward/record.url?scp=84922106059&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84922106059&partnerID=8YFLogxK

U2 - 10.1007/s12194-014-0300-3

DO - 10.1007/s12194-014-0300-3

M3 - Article

C2 - 25404493

AN - SCOPUS:84922106059

VL - 8

SP - 125

EP - 134

JO - Radiological Physics and Technology

JF - Radiological Physics and Technology

SN - 1865-0333

IS - 1

ER -