Current situations and discussions in Japan in relation to the new occupational equivalent dose limit for the lens of the eye

Yokoyama, Sumi*; Hamada, Nobuyuki*; Hayashida, Toshiyuki*; Tsujimura, Norio; Tatsuzaki, Hideo*; Kurosawa, Tadahiro*; Nabatame, Kuniaki*; Oguchi, Hiroyuki*; Ono, Kazuko*; Kawaura, Chiyo*; et al.

Journal of Radiological Protection, 37(3), p.659 - 683, 2017/09

https://doi.org/10.1088/1361-6498/aa73e8

Since the International Commission on Radiological Protection recommended reducing the occupational equivalent dose limit for the lens of the eye in 2011, there have been extensive discussions in various countries. This paper reviews the current situations in radiation protection of the ocular lens and the discussions on the potential impact of the new lens dose limit in Japan. Topics include historical changes to the lens dose limit, the current situations in occupational lens exposures (e.g., in medical workers, nuclear workers, and Fukushima nuclear power plant workers) and measurements, and the current status of biological studies and epidemiological studies on radiation cataracts. Our focus is on the situations in Japan, but we believe such information sharing will be useful in many other countries.

Interim report of the JHPS expert committee on radiation protection of the lens of the eye, 2; The Dosimetry method for the lens of the eye of workers in Japan

Akahane, Keiichi*; Iimoto, Takeshi*; Ichiji, Takeshi*; Iwai, Satoshi*; Oguchi, Hiroyuki*; Ono, Kazuko*; Kawaura, Chiyo*; Tatsuzaki, Hideo*; Tsujimura, Norio; Hamada, Nobuyuki*; et al.

Hoken Butsuri, 49(3), p.153 - 156, 2014/09

https://doi.org/10.5453/jhps.49.153

A brief review is given of the history and methodology of external dosimetry for the lens of the eye. Under the 1989 revision to domestic radiological protection regulations, the concept on the effective dose equivalent and the dose limit to the lens of the eye (150 mSv/y) both introduced in ICRP 1977 recommendations has changed nationwide the external monitoring methodology in non-uniform exposure situations to the trunk of a radiological worker. In such situations, often created by the presence of a protective apron, the worker is required to use at least two personal dosemeters, one worn on the trunk under the apron and the other, typically, at the collar over the apron. The latter dosemeter serves the dual purpose of providing the dose profile across the trunk for improved effective dose equivalent assessment and of estimating the dose to lens of the eye. The greater or appropriate value between (10) and (0.07), given by the dosemeter, is generally used as a surrogate of (3).

Report on the questionnaire about the data of atoms, molecules and atomic nuclei for medicine, 2004

Kobayashi, Toru*; Harata, Yasuo*; Matsufuji, Naruhiro*; Hasegawa, Tomoyuki*; Endo, Akira; Moribayashi, Kengo; Akahane, Keiichi*; Uehara, Shuzo*; Imahori, Yoshio*; Kato, Yo*; et al.

JAEA-Review 2006-002, 101 Pages, 2006/02

JAEA-Review-2006-002.pdf:5.53MB

This report provides an analysis of the results of the survey conducted among field experts regarding the data on atoms, molecules, and atomic nuclei used in medical applications. The important results are summarized as follows: First, the importance of the basic data for disciplines involved in medical research, i.e. physics and engineering, chemistry, pharmacology, biology, and the related data which are applied directly in medicine were identified. The related data are of greater importance in direct medical application compared to conventional basic data. Therefore, the data related to biology should be prepared in consideration of their convenient usage. Second, regarding the fundamental data on atoms, molecules and atomic nuclei related to medicine, the present data was able to approximately cope with the demands of many medical cases that needed data on quality, quantity, precision, etc. However, we found situations particularly in the IT community where comprehensively organized data was urgently needed. The data to be used for practical implementation must contain the specialized data for medical physics and biology. Finally, the significance of the continuity in the planned completion of the basic data was confirmed for the development of the associated fields. The expansion and completion of basic data should be done continuously and effectively while considering the limitation in resources and manpower.

Optimal control of ultrafast selection

Yokoyama, Keiichi; Teranishi, Yoshiaki; Toya, Yukio; Shirai, Toshizo; Fukuda, Yuji; Aoyama, Makoto; Akahane, Yutaka; Inoue, Norihiro*; Ueda, Hideki; Yamakawa, Koichi; et al.

Journal of Chemical Physics, 120(20), p.9446 - 9449, 2004/05

https://doi.org/10.1063/1.1752882

Optimal laser control for ultrafast selection of closely-lying excited states, whose energy separation is smaller than the laser bandwidth, is reported on the two-photon transition of atomic cesium; Cs(6S 7D, J = 5/2 and 3/2). Selective excitation was carried out by pulse shaping of ultrashort laser pulses which were adaptively modulated in a closed-loop learning system handling eight parameters representing the electric field. Two-color fluorescence from the respective excited states was monitored to measure the selectivity. The fitness used in the learning algorithm was evaluated from the ratio of the fluorescence yield. After fifty generations, a pair of nearly transform-limitted pulses were obtained as an optimal pulse shape, proving the effectiveness of "Ramsey fringes" mechanism. The contrast of the selection ratio was improved by 30 % from the simple "Ramsey fringes" experiment.

Controlling the phase matching conditions of optical parametric chirped pulse amplification using partially deuterated KDP

Ogawa, Kanade; Sueda, Keiichi*; Akahane, Yutaka; Aoyama, Makoto; Tsuji, Koichi; Fujioka, Kana*; Kanabe, Tadashi*; Yamakawa, Koichi; Miyanaga, Noriaki*

no journal, , 

Using a partially deuterated KDP crystal for an optical parametric amplifier, we demonstrated ultrabroadband optical parametric chirped-pulse amplification of more than 250 nm bandwidth at a center wavelength of 1050 nm. We numerically show how to control the broadband phase matching conditions at different wavelengths to match center wavelengths of suitable broadband seed sources by adjusting the deuteration level in partially deuterated KDP.

Optimization for OPCPA phase matching condition using partially deuterated KDP

Ogawa, Kanade; Sueda, Keiichi*; Akahane, Yutaka; Aoyama, Makoto; Tsuji, Koichi; Fujioka, Kana*; Kanabe, Tadashi*; Miyanaga, Noriaki*; Yamakawa, Koichi

no journal, , 

Using a partially deuterated KDP crystal for an optical parametric amplifier, we demonstrated ultrabroadband optical parametric chirped-pulse amplification of more than 250 nm bandwidth at a center wavelength of 1050 nm. We numerically show how to control the broadband phase matching conditions at different wavelengths to match center wavelengths of suitable broadband seed sources by adjusting the deuteration level in partially deuterated KDP.

Developing the database on medical exposure to CT in NIRS in collaboration with WAZA-ARI

Akahane, Keiichi*; Ono, Koji*; Okuda, Yasuo*; Sato, Kaoru; Takahashi, Fumiaki; Ban, Nobuhiko*; Shimada, Yoshiya*; Endo, Akira; Kai, Michiaki*

no journal, , 

The WAZA-ARI is a dose calculator of medical exposures on X-ray CT examinations, which is the web-based program based on the simulation data of voxel phantoms of Japanese adults and a 4-y girl. After the development, the WAZA-ARI has been installed in a web server of National Institute of Radiological Sciences (NIRS), and opened to the public as trial uses on Dec 2012. The user authentication function and the data input pages by users have been adding to the WAZA-ARI to store the calculated data and the inputted data of doses and frequencies of X-ray CT examinations into the database on medical exposure in NIRS for the analyses of the CT exposures. The use of these functions and WAZA-ARI II, which can calculate the doses of different patients' body sizes, will provide the basic and useful data on the CT exposures for the radiation protection in medicine, because the portion of CT doses in the overall medical exposures are relatively high compared to other radiological diagnoses.

Evaluation of the tube-voltage dependence of organ doses in X-ray CT scans using Monte-Carlo calculation

Koba, Yusuke*; Matsumoto, Shinnosuke*; Nakada, Yoshihiro*; Kasahara, Tetsuji*; Akahane, Keiichi*; Okuda, Yasuo*; Sato, Kaoru; Takahashi, Fumiaki; Yoshitake, Takayasu*; Hasegawa, Takayuki*; et al.

no journal, , 

Many of the CT devices are in Japan. It is guessed that exposure doses of Japanese derived from CT scans are higher than others. Thus, it is needed to properly manage scan conditions and exposure doses of individual patients. JAEA developed WAZA-ARI under the collaboration research project with the National Institute of Radiological Sciences (NIRS) and the Oita University of Nursing and Health Sciences. Practical use of new version WAZA-ARI named WAZA-ARIv2 began on January 30, 2015 at the web server in NIRS. In WAZA-ARIv2, users can calculate patients doses by using only standard condition (120 kV) of X-tube voltage. In recent years, CT scans at low tube voltage against pediatric patients with high radiosensitivity are increasing. In this study, spectrum of X-ray derived from CT scan at low tube voltage was examined, and was defined in "usrsors.f" file of PHITS. We reported the characteristics of X-ray and organ doses derived from CT scan at low tube voltage (80 kV).

Analysis of effects of body sizes on organ doses due to CT examinations by using voxel phantoms

Sato, Kaoru; Takahashi, Fumiaki; Koba, Yusuke*; Ono, Koji*; Yoshitake, Takayasu*; Hasegawa, Takayuki*; Katsunuma, Yasushi*; Kasahara, Tetsuji*; Okuda, Yasuo*; Nakada, Yoshihiro*; et al.

no journal, , 

JAEA is now developing CT dose calculator named WAZA-ARIv2 in cooperation with the National Institute of Radiological Sciences. WAZA-ARIv2 has been opened to the public as full-dress uses on January 2015. WAZA-ARIv2 can perform dose assessment against 4 different body physiques by using the organ dose database, which were constructed on the basis of adult Japanese phantoms with 4 body sizes (-2, average, +2, +5). In this study, it was found that salivary gland doses are independent on BMI, whereas lung doses are dependent on BMI. The differences in the effects of BMI on absorbed doses between salivary glands and lungs might be caused by the difference in thickness of subcutaneous soft tissues between head and thorax.