Key Issues associated withRadiation Protection~ Brief Overview of Activities in JHPS ~Toshiso KOSAKOPresident, Japan Health Physics Society (JHPS)
Professor, The University of Tokyo
HPS-JHPS Joint Special Session
The 47th Annual Meeting of the Japan Health Physics SocietyContents
 Key Issues of RP under discussion in JHPS

 Japanese Standardization Committee on Radiation
Protection
 Expert Groups on: Development of the Standardizationof in vivo measurements
 Radiation Protection for Eye Lens

 The second set of recommendations from JHPS on Radiation
Protection Issues after Fukushima Accident(by Takatoshi HATTORI) Recent Activities of the Young Researchers Association of JHPS
(by Yuki MORISHITA)
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Japanese Standardization
Committee on Radiation Protection

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Standardization Committee
 To understand radiation
safety and its management
effectively and easily,
Japanese nuclear/radiation
users as well as regulators
have required thefundamental Japanesestandards on RP based on theglobal standards.
 Standardization Committee
on RP was organized in JHPS
in June 2006.
 Standards on RP consist
mainly of four classes; theprinciple, important concepts,
criteria and guidelines.
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Ongoing 4 working groups
1. Radioactive waste management in existing exposuresituation
2. Management systema.
b.

Daily survey of surface contamination
Screening level for reuse/recycle in existing exposure situation

3. Incorporation of ICRP 2007 recommendations
a.
b.
c.

Recording, investigation and intervention levels for internal
dose management
Necessity of special medical examination for radiation workers
Management of female workers during a pregnancy period

4. Safety for activated materials around accelerator
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Activities of Expert Group on
Development of the Standardizationof in vivo measurements

6What is this Expert Group?
Background A large number of whole-body measurements for residents (including children)
have been performed in Fukushima and other prefectures in Japan.
 Many whole-body counters (WBCs) by several manufacturers have been installed.
(~ 50 WBCs only in Fukushima).
 There is a growing need for demonstrating the concept for internal dose
measurements for the public and the standardization of instruments for in vivo
measurement in Japan.

Technical issues discussed

 Classification and requirements for the instruments for in vivo measurements
 Maintenance and calibration of the instruments (e.g., calibration phantom)
 Concept of internal dose assessments for members of the public Reports and explanation of measurement results
Members
Chief: O. Kurihara (NIRS), Organizer: T. Nakano (NIRS)
and other 24 experts (research scientists, manufacturers, users and so on )Period of activity
June 2012 ~ March 2014 (two meetings between the members)
7Outputs from this Expert Group (1)Development of domestic standard (JIS) for in vivo counters (on going) Several members of the expert group have been involved in the development ofa domestic standard for in vivo counters based on IEC 61582.

Accuracy survey of WBCs in Fukushima (by NIRS)

Relative bias (= indicated / reference activity of 137Cs)

 Circulation of a set of BOMAB phantoms to WBC facilities in Fukushima(~40 WBCs in total) for the accuracy survey

The relative bias is within 10%
for almost all the WBCs investigated.

Blue bar: Installed WBC
Red bar: Mobile WBC
This work is conducted as a part of the funded research by
Ministry of Environment in 2012 and 2013.

BOMAB phantom could be utilized asa de facto standard with consensus
from WBC users.
(*IEC does not give the specification ofcalibration phantoms.)

8Outputs from this Expert Group (2)Internal dose assessments based on WB measurements
 Compilation of datasets converting the body content of Cs to the effective dose
based on a chronic intake scenario via ingestion for the use in WB measurements

Consideration on body size correction for WBCs

137Cs peak efficiency (count/photon) Investigation on body size correction methods used in commercial WBCs Experiments using phantoms with different body sizes
3.0E-02
2.5E-02

WBC A
WBC B

y = 0.0143x-0.846
R² = 0.9728

2.0E-02y = 0.0146x-0.68
R² = 0.923

1.5E-02

The body surface area is a goodparameter for building an eq. for thebody size correction in WBCs.

1.0E-02
5.0E-03

WBC A with car seat

0.0E+00
0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Body surface area (m2)

1.8

2.0

However, a car seat for supporting smallchildren in measurements would becomplicated in the correction...

Remained issues
 Peak area calculations for pulse height spectra from WBCs
 Guidelines for the maintenance of instruments (mainly for operators)
The report of this expert group is now preparing.
9Activities of Expert Group on
Radiation Protection for Eye Lens

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What is this Expert Group?
AimTo consider implication and implementation of the new ICRP dose limit of thelens of the eye to the Japanese regulations of radiation protection and safety
Members
Chief: K. Akahane (NIRS), Organizer: S. Yokoyama (Fujita Health Univ.)and other 11 experts including health physicists, doctors and a medical physicist
Period of activity
April 2013 ~ March 2016

The committee started to investigate the present national andinternational conditions; Scientific evidences for the dose limit
 Development of dosimetry
 Exposure for high level radiation exposure workers
11Activities
May 25, 2013

June 24, 2013

Work shop for the implementation of newdose limit of the lens of the eye & The 1stCommittee meeting
Open meeting on The 46th JHPS annual
meeting (Ciba, Japan) & The 2nd Committee
meeting

Sep. 27, 2013

The 3rd Committee meeting

Feb. 6, 2014

The 4th Committee meeting

Mar. 25, 2014

The 5th Committee meeting

The Interim report of this expert group is now preparing.
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Contents of Interim report (tentative)
1. Introduction
2. The lens of the eye and the cataract
3. History of ICRP dose limit of the lens of the eye and its
scientific evidences
4. International actions concerned with new ICRP doselimit of the lens of the eye
5. Several project studies related with the dosimetry andexposure of the lens of the eye
6. Present monitoring and dosimetry of the lens of the eyefor Japanese radiation workers in the medical, nuclear
and industrial fields
7. Our future issues
13Our future issues• System of radiation protection of the lens of the eye and scientificevidence → Outside of our future work ?
– Stochastic or Deterministic effect?
– Animal experimental or human epidemiological results?
– Standardization of human epidemiology study etc.

• Dosimetry of the lens of the eye– Conversion coefficients (particularly for neutron)– Applicable dosimeters– Measurement positions and incidence angles etc.

• Exposure of the lens of the eye for Japanese radiation workers– Lack of the data for Japanese radiation workers– Education and consideration of radiation protection etc.

• Radiation protection and dose estimation of the lens of the eye forrecovery workers of Fukushima Daiichi Nuclear accident
Future analysis in the committee

Recommendation from the Expert Group14

Summary JHPS have been identifying and discussing
the important issues associated with radiation
protection
 JHPS will further discuss those issues incooperation with overseas associatedsocieties such as AOARP, IRPA and HPS.

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