The detection of radiation induced radicals from teeth enamel by in - - PowerPoint PPT Presentation

The detection of radiation induced radicals from teeth enamel by in vivo EPR ( Electron paramagnetic Resonance) Dosimetry

Urgent funding for international collaborative research that arises from earthquake and subsequent tsunami and nuclear accidents

JST project No.20

Japanese Research Team

Minoru Miyake１, Ichiro Yamaguchi ２, Michitaka Umakoshi 1, Hiroshi Hirata 3, Naoki Kunugita２, Yoshiro Matsui １, Akinori Iwasaki1

1Department of Oral and Maxillofacial Surgery, Faculty of

Medicine, Kagawa University, Kita-gun, Japan

2 Department of Environmental Health, National Institute of

Public Health, Wako, Japan

3 EPR group in the Division of Bioengineering and

Bioinformatics, Hokkaido University, Sapporo, Japan

Harold M.Swartz Dartmouth Medical School, Department of Radiology and Medicine Professor MD, PhD （研究者）

Benjamin B. Williams Dartmouth Medical School, Department of Radiology and Medicine Assistant Professor PhD Stwarts, Steven G. Unversity of Florida Professor PhD Flood, Ann B. Dartmouth Medical School Professor PhD Duinan, Eva C. Dana Farber Cancer Institute Professor MD Hyde, James S. Medical college of Wisconsin Professor PhD Lesniewski Piotr Dartmouth Medical School, Department of Radiology and Medicine Associate Professor M.S.E.

US Research Team

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wi with the th the US team S team. Ｔｈｉｓ project includes following issues ; 1)Develop techniques to make the measurements using the incisors (extending in Japan the capabilities that previously were for premolar or molar teeth) 2)To make measurements from upper incisor with volunteers who live in FUKUSHIMA

１．Uncomfortable, because saliva easily accumulate in the deep of the throat. ２．It is difficult to firm fixation of the detector loop on molar or premolar. ３．Limited field of view between the magnet at the lying down position makes the volunteer nervous or anxious .

We developed “incisor measurement on the sitting position supported by Dart-Dose CMCR and installed in the clinical system in NIPH.

The problems on “lying down” position

A wooden frame containing no magnetic materials was made for firmly but comfortably holding the head of volunteers sitting in a chair during the measurement. The resonator is held on the distal end of a lockable articulating arm that is mounted to wooden frame.

Lying down measurement Sitting measurement

0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 1 2 3 4 5

lying down sitting

field 計測点 Signal intensity (a.u.)

Noise Peak lying down sitting Noise mean 0.278 0.118 SD 0.093 0.044 SN(PDT)ratio 1.21 2.03

• 2.50E-01
• 2.00E-01
• 1.50E-01
• 1.00E-01
• 5.00E-02

0.00E+00 5.00E-02 1.00E-01 1.50E-01

• 1.00E+01
• 5.00E+00

0.00E+00 5.00E+00 1.00E+01 1.50E+01 2.00E+01

y

• 6.50E+00
• 6.48E+00
• 6.45E+00
• 6.43E+00
• 6.40E+00
• 6.38E+00
• 6.35E+00
• 6.33E+00
• 6.30E+00
• 6.28E+00
• 6.26E+00
• 1.40E-01
• 1.20E-01
• 1.00E-01
• 8.00E-02
• 6.00E-02
• 4.00E-02
• 2.00E-02

0.00E+00 2.00E-02 4.00E-02 6.00E-02

• 1.00E+01 -5.00E+00 0.00E+00 5.00E+00 1.00E+01 1.50E+01 2.00E+01

y

y

Fukushima Daiichi Nuclear Plant

Okum a Minami Soma Kawauchi Tamura Date Itate Som a Nihonmatsu Motomiya Koriyama Katsurao Namie Tomiok a Narah a Iwaki Hirono Fukushima

10Km

* * * * * * * * * * * * * * * * * * * * * * * * * * *

Materials and Methods

35 volunteers were enrolled in this study (male 15, Female 18, average age was 25 years). All volunteers had at least one complete healthy upper incisor. They were residents in Fukushima prefecture within the 60-80km distance from FUTABA-Machi where the FUKUSHIMA Nuclear Power plant I is located.

1.2 GHz (L-band) using a 41 mT permanent magnet with 50 cm pole separation. All measurements are performed using surface loop resonators that have been specifically designed for EPR measurements of the upper incisor teeth.

This protocol has been approved by the IRBs of NIPH (National Institute of Public Health, Japan), NIPH-IBRA#10039 and Kagawa University, Heisei#24-4.

0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 5 10 15 20 25 30

EPR signals

(a.u.) (volunteer no.）

Results

Signal intensity0.04011±0.00716 a.u.

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 5 10 15 20 25 30

EPR/PDT ratio

(volunteer no.）

0.2153±0.00284 a.u.

The teeth were positioned by use of a bite plate system which gently held the upper lip and kept the resonator loop on the surface of the tooth.

Conclusions

• 1. We were able successfully to carry out,

in vivo EPR measurements from human upper incisors in volunteers from Fukushima.

• 2. There were no indications of radiation-

induced signals above background.

Future studies will focus on:

• 1. More detailed analysis of the background

signals by increasing the number of volunteers who are measured

• 2. Determining the feasibility of longer

measurements to lower the threshold level for detection of radiation-induced signals

• 3. Establishing the procedures for obtaining

background measurements in individuals with a higher risk of exposure in the future

• 4. We also will seek to determine the

psychological benefits for volunteers who have been measured.

We appreciate the support from JST THANK YOU FOR YOUR ATTENTION