03-30生体磁気-学会誌-抄録集.qxp_レイアウト 1 2015/05/22 18:02 ページ 8
生体磁気計測のための新技術開発と今後
日本生体磁気学会誌 特別号
S1-2
Vol.28 No.1 2015　第 30 回日本生体磁気学会大会論文集
ཧ↷ಙྕࡢ࢔ࢼࣟࢢࣇ࢕࣮ࢻࣂࢵࢡ࡟ࡼࡿ
ప࿘Ἴ⎔ቃ☢ሙ㞧㡢పῶ
Reduction of low band circumstance magnetic field noise by
analog feedback of reference signals
㊊❧ၿ᫛(1)㸪᫓⏣ᗣ༤(1)㸪ᕝ➃ⱱᚨ(2)㸪➲㔝ဴ㑻(2)㸪ୖཎᘻ(1)
㔠ἑᕤᴗ኱Ꮫඛ➃㟁Ꮚᢏ⾡ᛂ⏝◊✲ᡤᮾி་⛉ṑ⛉኱Ꮫ
Yoshiaki Adachi (1), Yasuhiro Haruta (1),
Shigenori Kawabata (2), Tetsuo Sasano (2) and Gen Uehara (1)
(1) Applied Electronics Laboratory, Kanazawa Institute of Technology
(2) Tokyo Medical and Dental University
Abstract Biomagnetic signal are extremely weak.
Therefore, highly sensitive magnetic flux sensors such
as superconductive quantum interference device
(SQUID) are applied to detect it. The highly sensitive
magnetic field measurement is often suffered from
ultra low frequency extra extramural noise caused by
transportation especially in urban area. We applied a
direct analog feedback from reference sensors to our
124-ch magnetospinography system and the low band
circumstance noise was successfully reduced.
పῶࢆヨࡳࡓࠋ
2. ⬨ ☢ ィ
᪤ሗࡢ 124ch SQUID ⬨☢ィࢩࢫࢸ࣒[1]࡟ࠊཧ↷
ಙྕ࡜ࡋ࡚⎔ቃ☢ሙ㞧㡢ࢆࣔࢽࢱࡍࡿ SQUID ☢
᮰ィࢆ㏣ຍࡋࡓࠋ⬨㧊ࡸᚰ⮚ࡢ☢ሙࢆ᳨ฟࡍࡿ
SQUID ☢᮰ィࡢ᳨ฟࢥ࢖ࣝࡣ 1 ḟᕪศᆺ࡛࠶ࡿࡀࠊ
ཧ↷ಙྕ⏝ࡢ SQUID ☢᮰ィࡣᕪศ࡞ࡋࡢ᳨ฟࢥ
࢖࡛ࣝࠊ┤஺ࡍࡿ 3 ᪉ྥࡢ☢ሙᡂศࢆ᳨ฟ࡛ࡁࡿ
ࡼ࠺࡟ࠊ3 ࡘࡢ SQUID ࡀ⤌ࡳྜࢃࡉࢀ࡚࠸ࡿࠋ
ᚑ᮶ࠊ⬨☢ィࡢ FLL ᅇ㊰ࡢᖏᇦࡣ 10 Hz㹼12 kHz
࡜ࡋ࡚࠸ࡓࡀࠊࡇࢀࢆᚰ☢ಙྕ᳨ฟ᫬ࡣ 0.16 Hz
㹼12 kHz ࡜ࡋࡓࠋ୍᪉ࠊཧ↷ಙྕ⏝ࡢ FLL ᅇ㊰ࡢ
ᖏᇦࡣ DC㹼10 Hz ࡜ࡋࡓࠋ
1. ࡲ ࠼ ࡀ ࡁ
ࢃࢀࢃࢀࡣ⬨㧊ࡢάື࡟కࡗ࡚Ⓨ⏕ࡍࡿᚤᙅ࡞
☢ሙࢆ SQUID ᳨࡛ฟࡋࠊ⬨㧊⑌ᝈࡢᶵ⬟ⓗデ᩿
ࢆ⾜࠺⬨☢ィࡢ㛤Ⓨࢆ㐍ࡵ࡚࠸ࡿ[1]ࠋ㛤Ⓨࡋࡓ⬨
☢ィࡣ௮⮩఩ࡢ⿕㦂⪅ࡢ⫼ഃ࡟ࢭࣥࢧࢆ㏆᥋ࡉࡏ
ࡿࡢ࡟㐺ࡋࡓ≉Ṧ࡞ᙧ≧ࡢࢹࣗ࣡࡜ࠊ⊃࠸㡿ᇦ࠿
ࡽຠ⋡ࡼࡃ☢ሙ᝟ሗࢆྲྀᚓ࡛ࡁࡿࡼ࠺࡟య⾲㠃࡟
ᑐࡋ࡚ἲ⥺᪉ྥ࡜᥋⥺᪉ྥࡢᡂศࢆྠ᫬࡟᳨ฟࡍ
ࡿ࣋ࢡࢺࣝᆺࡢ SQUID ᕪศᆺ☢᮰ィࢆ⿦ഛࡋ࡚
࠸ࡿࠋࡑࡋ࡚ࠊẚ㍑ⓗ῝㒊ࡢ☢ሙ※ࢆᑐ㇟࡜ࡍࡿ
ࡓࡵࠊ⣙ 70 mm ࡜୍⯡ⓗ࡞⬻☢ィࡼࡾࡶ࣮࣋ࢫࣛ
࢖ࣥ㛗ࡢ㛗࠸ᕪศࢥ࢖ࣝࢆ㐺⏝ࡋ࡚࠸ࡿࠋ
ࡇࢀࡽࡢ≉ᚩ࡟╔┠ࡋࠊ⬨☢ィࢆ⫼ഃ࠿ࡽࡢᚰ
☢ሙ ᐃ࡟㐺⏝ࡋࡓ᪂ࡋ࠸᳨ᰝἲࡀ᳨ウࡉࢀ࡚࠸
ࡿ [2]ࠋ⬨☢ィࢆᚰ⮚☢ሙ᳨ฟ࡟ᛂ⏝ࡍࡿ࡟࠶ࡓࡗ
࡚ၥ㢟࡜࡞ࡿࡢࡣࠊ㏆㞄ࡢ㕲㐨࡞࡝࠿ࡽࡢప࿘Ἴ
⎔ቃ☢ሙ㞧㡢࡛࠶ࡿࠋ
ࡑࡇ࡛ࠊ⬨☢ィࡢࢭࣥࢧ࢔ࣞ࢖࡜ࡣู࡟⎔ቃ☢
ሙ㞧㡢ࢆࣔࢽࢱࡍࡿ SQUID ☢᮰ィࢆ⏝ពࡋࠊࡑ
ࡢฟຊࢆཧ↷ಙྕ࡜ࡋ࡚ࠊప࿘Ἴ⎔ቃ㞧㡢☢ሙࡢ
3. ཧ ↷ ಙ ྕ ࡟ ࡼ ࡿ 㞧 㡢 ప ῶ
ᮏ◊✲࡛㐺⏝ࡋࡓప࿘Ἴ⎔ቃ㞧㡢☢ሙపῶἲࡣࠊ
ᅗ1࡟♧ࡍࡼ࠺࡟ࠊ3ࡘࡢཧ↷ಙྕ⏝SQUID☢᮰ィ
᳨࡛ฟࡋࡓ⎔ቃ☢ሙ㞧㡢࡟㐺ᙜ࡞㔜ࡳࢆ࠿ࡅ࡚ࠊ
SQUID☢᮰ィ࡟ΰධࡍࡿ☢ሙ㞧㡢ࢆྜᡂࡋࠊࡑࢀ
ࢆSQUID☢᮰ィࡢࣇ࢕࣮ࢻࣂࢵࢡࢥ࢖ࣝ࡟┤᥋
༳ຍࡍࡿࡇ࡜࡟ࡼࡗ࡚࢟ࣕࣥࢭࣝࡍࡿࡶࡢ࡛࠶ࡿࠋ
ࡇࡇ࡛ࡣ౽ᐅୖࠊ┤᥋࣮࢜ࣉ࣮ࣥࣝࣉྠ┦ᡂศධ
ຊἲ(Direct Open-Loop in-Phase component Input:
DOLPHIN)࡜࿧ࡪࡇ࡜࡟ࡍࡿࠋm␒┠ࡢSQUID☢
᮰ィࡢ㞧㡢పῶࡢࡓࡵࡢྛཧ↷ಙྕࡢ㔜ࡳࡣࠊ࠶
ࡽ࠿ࡌࡵ ᐃࡋࡓ㐺ᙜ࡞㛗ࡉ(T1㹼T2)ࡢప࿘Ἴ☢
ሙ㞧㡢ࢹ࣮ࢱࢆࡶ࡜࡟ࠊḟࡢホ౯㛵ᩘLࢆ᭱ᑠ࡟
ࡍࡿwm=(wxm, wym, wzm)࡜ࡋ࡚Ỵᐃ࡛ࡁࡿࠋ
L=
8
$
#2
T1
(xm (! ) ! w m " n(! ))2 d !
(1)
03-30生体磁気-学会誌-抄録集.qxp_レイアウト 1 2015/05/22 18:02 ページ 9
日本生体磁気学会誌 特別号
Vol.28 No.1 2015　第 30 回日本生体磁気学会大会論文集
ࡇࡇ࡛ࠊxm(t)ࡣSQUIDᕪศᆺ☢᮰ィࡢฟຊ࡛ࠊ
n(t)=(nx(t), ny(t), nz(t))ࡣཧ↷ಙྕ⏝ࡢSQUID☢᮰ィ
ࡢฟຊ࡛࠶ࡿࠋ⤖ᯝ࡜ࡋ࡚ࠊxm(t)࡜wm࣭n(t)ࡢ┦
㛵ࡀ᭱ࡶ㧗ࡃ࡞ࡿࡼ࠺࡟wmࡀồࡲࡿࠋỴᐃࡋࡓwm
ࡣྛSQUID࡟ࡘ࠸࡚⏝ពࡉࢀࡓࣉࣟࢢ࣐ࣛࣈࣝ
ࢤ࢖ࣥ࢔ࣥࣉࡢࢤ࢖ࣥ࡜࡞ࡿࠋ
ࡇࡢࡼ࠺࡟SQUID☢᮰ィࡢࣇ࢕࣮ࢻࣂࢵࢡࢥ
࢖ࣝ࡟┤᥋ཧ↷ಙྕࡢฟຊࢆ༳ຍࡋ࡚⎔ቃ☢ሙ㞧
㡢ࢆపῶࡍࡿ᪉ἲ࡟ࡣࠊ┤᥋ࣇ࢕࣮ࢻࣂࢵࢡᕪศ
ᆺ☢᮰ィࡀᥦ᱌ࡉࢀ࡚࠸ࡿࡀ[3]ࠊDOLPHINࡣᑡᩘ
ࡢཧ↷ಙྕ⏝ࢭࣥࢧ࡛ከᩘࡢ⏕య☢ሙ᳨ฟ⏝ࢭࣥ
ࢧࡢࣀ࢖ࢬࢆపῶ࡛ࡁࠊࡲࡓࠊཧ↷ಙྕ⏝ࢭࣥࢧ
ࡢឤᗘ᪉ྥࢆ⏕య☢ሙ᳨ฟ⏝ࢭࣥࢧ࡟ᥞ࠼ࡿᚲせ
ࡀ࡞ࡃࠊከࢳࣕࣥࢿࣝࢩࢫࢸ࣒࡟㐺ࡋ࡚࠸ࡿࠋ
4. ᐇ 㦂 ࡜ ⤖ ᯝ
ᮾி་⛉ṑ⛉኱Ꮫࡢ☢Ẽࢩ࣮ࣝࢻ࣮࣒ࣝෆ࡟タ
⨨ࡉࢀࡓ⬨☢ィ࡛ࠊ⎔ቃ☢ሙ㞧㡢ࢆྵࡴࢩࢫࢸ࣒
ࣀ࢖ࢬࢆDOLPHIN࠶ࡾࠊ࡞ࡋࡢ୧᪉࡛ ᐃࡋࡓࠋ
ᐃᖏᇦࡣ0.16 Hz㹼5 kHzࠊ㔜ࡳࢆỴᐃࡍࡿࡓࡵ
ࡢணഛ ᐃࡢ᫬㛫ࢆ60⛊㛫࡜ࡋࡓࠋᅗ2ࡣࡑࡢ⤖ᯝ
ࢆẚ㍑ࡋࡓࡶࡢ࡛ࠊ(a)ࠊ(b)ࡣࡑࢀࡒࢀ඲ࢳࣕࣥࢿ
ࣝࡢฟຊἼᙧࢆ㔜␚ࡋࡓࣉࣟࢵࢺ࡜඲ࢳࣕࣥࢿࣝ
ࡢFFTࡢᖹᆒࡢࣉࣟࢵࢺ࡛࠶ࡿࠋDOLPHINࢆ㐺⏝
ࡋ࡞࠸ሙྜ࡟ẚ࡭࡚ࠊ⣙90%ࡢప࿘Ἴ⎔ቃ☢ሙ㞧
㡢ࢆపῶࡍࡿࡇ࡜ࡀ࡛ࡁࡓࠋ㟁※࿘Ἴᩘࡢࣀ࢖ࢬ
࡜ࡑࡢ㧗ㄪἼࠊ࠾ࡼࡧⓑⰍ㞧㡢ࣞ࣋ࣝ࡟ࡣᙳ㡪ࡀ
࡞࠿ࡗࡓࠋ
ᅗ 1 DOLPHIN ࡢࣈࣟࢵࢡᅗ
5. ⤖ ㄒ
」ᩘࡢཧ↷ಙྕࡢ⥺ᙧ⤖ྜ࿴ࢆࠊ┤᥋ࠊSQUID
ࡢࣇ࢕࣮ࢻࣂࢵࢡࢥ࢖ࣝ࡬༳ຍࡍࡿ DOLPHIN ࢆ
㐺⏝ࡋࠊ☢Ẽࢩ࣮ࣝࢻ࣮࣒ࣝࡸᕪศᆺࣆࢵࢡ࢔ࢵ
ࣉࢥ࢖࡛ࣝࡣ㝖ཤࡋࡁࢀ࡞࠸ప࿘Ἴ⎔ቃ☢ሙ㞧㡢
ࢆࡉࡽ࡟ 10 ศࡢ 1 ࡟పῶࡍࡿࡇ࡜ࡀ࡛ࡁࡓࠋ
ㅰ㎡
ᮏ◊✲ࡣ⛉Ꮫ◊✲㈝ຓᡂ஦ᴗ㸦ㄢ㢟␒ྕ
26282149㸧ࡢᨭ᥼ࢆཷࡅ࡚⾜ࡗࡓࠋ
ཧ⪃ᩥ⊩
[1] ㊊❧ၿ᫛ ௚, 2014, ᪥ᮏ⏕య☢ẼᏛ఍ㄅ≉ู
ྕ, 27(1), 86–87.
[2] ኱▮㯞⨾Ꮚ ௚, 2015, ᪥ᮏ⏕య☢ẼᏛ఍ㄅ≉
ูྕ, 28(1), ᥖ㍕ணᐃ
[3] K. Yokosawa, S. Kuriki, 1994, Rev. Sci. Inst., 65,
3814̽3819.
ᅗ 2 DOLPHIN ࠶ࡾࠊ࡞ࡋࡢ⎔ቃ☢ሙ㞧㡢ẚ㍑
9

IPCCの政府承認プロセスは崩壊しているか? By Robert Stavins http

0 0 ￠ N ？ L S く S ↑ ∝ 山 0 0 U u u J 0 ∝ ト Z O U ︰ O l m

論文参照 - 第30回日本生体磁気学会大会