Jpn. J. Med. Phys. Vol. 33 No. 1: 16–57 (2013)

解説

་⒪⏝ຍ㏿ჾ࡟࠾ࡅࡿࢥ࣑ࢵࢩࣙࢽࣥࢢࡢᶵჾ࡜ᡭ㡰⡿ᅜ་Ꮫ≀⌮Ꮫ఍࣭἞⒪≀⌮ጤဨ఍ࢱࢫࢡࢢ࣮ࣝࣉ 106 ࣏࣮ࣞࢺ
᪥ᮏㄒヂ

⩻ヂ⪅

⬥⏣ ᫂ᑦ㸦ᅜ❧ࡀࢇ◊✲ࢭࣥࢱ࣮୰ኸ⑓㝔 ᨺᑕ⥺἞⒪⛉㸧ᶫᮏ ៅᖹ㸦ࡀࢇ࣭ឤᰁ⑕ࢭࣥࢱ࣮㒔❧㥖㎸⑓㝔 ᨺᑕ⥺≀⌮ᐊ㸧Ἑෆ ᚭ 㸦༓ⴥ┴ࡀࢇࢭࣥࢱ࣮ ᨺᑕ⥺἞⒪㒊≀⌮ᐊ㸧ᑠᓥ ᚭ 㸦༓ⴥ┴ࡀࢇࢭࣥࢱ࣮ ᨺᑕ⥺἞⒪㒊≀⌮ᐊ⌧ ᇸ⋢┴❧ࡀࢇࢭࣥࢱ࣮ ᨺᑕ⥺἞⒪⛉㸧ᢞ✏࡟㝿ࡋ࡚
 ㏆ᖺࡢᨺᑕ⥺἞⒪ࡣࢥࣥࣆ࣮ࣗࢱࡢ㐍໬࡜࡜ࡶ࡟ࡵࡊࡲࡋ࠸ᢏ⾡㠉᪂ࢆ㐙ࡆ࡚࠾ࡾࠊᮏ㑥࡛ࡶࠊᙉᗘኚㄪᨺ
ᑕ⥺἞⒪ࠊᐃ఩ᨺᑕ⥺἞⒪ࢆࡣࡌࡵ࡜ࡍࡿ㧗⢭ᗘᨺᑕ⥺἞⒪ࡀከࡃࡢ᪋タ࡛ᐇ᪋ࡉࢀࡿࡼ࠺࡟࡞ࡗ࡚ࡁ࡚࠸ࡿࠋ
⌧ᅾ࡛ࡣࠊࡇࢀࡽࡢ㧗⢭ᗘᨺᑕ⥺἞⒪ࢆྵࡴ࡯࡜ࢇ࡝ࡢ἞⒪ィ⏬ࡣ 3 ḟඖ἞⒪ィ⏬⿦⨨ࢆ⏝࠸࡚❧᱌ࡉࢀ࡚࠾
ࡾࠊ἞⒪ィ⏬⿦⨨࡟࠾ࡅࡿ⥺㔞ィ⟬ࡢ࣮࣋ࢫ࡜࡞ࡿ἞⒪⿦⨨ࡢࣅ࣮࣒ࢹ࣮ࢱࡢṇ☜ࡉࡣࠊᝈ⪅ࡉࢇ࡬ᢞ୚ࡍࡿ
⥺㔞ࡢṇ☜ࡉ࡬┤⤖ࡋ࡚࠸ࡿࠋ ࡑࡢࡼ࠺࡞୰ࠊ2008 ᖺ࡟⡿ᅜ་Ꮫ≀⌮Ꮫ఍ࡼࡾࠊࣅ࣮࣒ࢹ࣮ࢱ

ᐃ࡟㛵ࡍࡿࢱࢫࢡࢢ࣮ࣝࣉ࣏࣮ࣞࢺ 106

㸦TG-106㸧ࡀⓎหࡉࢀࡓࠋTG-106 ࡣࠊࣜࢽ࢔ࢵࢡᑟධ᫬࡟࠾ࡅࡿࣅ࣮࣒ࢹ࣮ࢱ

ᐃࡢᢏ⾡ⓗഃ㠃ࠊ ᐃᶵჾࠊ࠾ࡼࡧయไ࡟㛵ࡋ࡚グ㏙ࡉࢀࡓ࣏࣮ࣞࢺ࡛࠶ࡾࠊ᪂ࡓ࡟⿦⨨ᑟධࡍࡿ㝿ࡸࠊ⥅⥆ⓗ࡞ရ㉁⟶⌮ࢆ⾜࠺㝿࡟᭷⏝࡞࣏࣮ࣞࢺ࡜࡞ࡗ࡚࠸ࡿࠋࡲࡓࠊཧ⪃ᩥ⊩ࡀ㇏ᐩ࡛࠶ࡾࠊࡼࡾヲ⣽࡞᝟ሗࢆồࡵࡿㄞ⪅ࡀ▱㆑ࢆᗈࡆࡿࡓࡵࡢ
ཧ⪃᭩࡜ࡋ࡚౑⏝ࡍࡿࡇ࡜ࡶྍ⬟࡛࠶ࡿࠋ ᡃࠎࡣࠊࡇࡢ TG-106 ࡀᮏ㑥࡛ࡶ᭷ຠ࡟ά⏝ࡉࢀࡿࡼ࠺ࠊ⮫ᗋ་Ꮫ≀⌮◊✲఍࠾ࡼࡧ᪥ᮏ་Ꮫ≀⌮Ꮫ఍ㄢ㢟ู◊✲⌜ࠕ㧗⢭ᗘእ㒊ᨺᑕ⥺἞⒪ࡢရ㉁ಖド࣭ရ㉁⟶⌮ࢩࢫࢸ࣒ࡢᵓ⠏ࠖ㸦◊✲௦⾲⪅ ᒸᮏ⿱அඛ⏕㸸ᅜ❧ࡀࢇ◊✲ࢭࣥࢱ࣮୰ኸ⑓㝔 ᨺᑕ⥺἞⒪⛉㸧ࡢ࣓ࣥࣂ࣮ࡢ༠ຊࡢࡶ࡜ࠊ⩻ヂసᴗࢆ㐍ࡵࠊࡇࡢᗘࠕ་Ꮫ≀⌮ࠖㄅ࡬ゎㄝ࡜࠸࠺ᙧ࡛ฟ∧ࡢᶵ఍ࢆᚓࡓࠋ࡛ࡁࡿࡔࡅ㏲ㄒヂࢆᚰ᥃ࡅࡘࡘࡶࠊព࿡ࡢ㏻ࡾࡸࡍ࠸᪥ᮏㄒ࡟࡞ࡿࡼ
࠺⪃៖ࡋࡓࡘࡶࡾ࡛࠶ࡿࡀࠊㄞࡳ࡙ࡽ࠸⟠ᡤࡀぢཷࡅࡽࢀࡓሙྜࡣࡈ஢ᢎ࠸ࡓࡔࡅࢀࡤᖾ࠸࡛࠶ࡿࠋཎᩥ࡟㛵ࡋ࡚ࡣࠊhttp://www.aapm.org/pubs/reports/ ࠿ࡽࣇ࣮࡛ࣜࢲ࣮࢘ࣥࣟࢻྍ⬟࡞ࡢ࡛ࠊㄞ⪅ࡢᚲせ࡟ᛂࡌ࡚ཎᩥࡶ
ཧ↷࠸ࡓࡔࡅࢀࡤ࡜ᛮ࠺ࠋ ࡇࡢ TG-106 ࣏࣮ࣞࢺ᪥ᮏㄒヂࡀࠊከࡃࡢᨺᑕ⥺἞⒪᪋タ࡛᭷ຠ࡟ά⏝ࡉࢀࠊᏳ඲࡛㧗⢭ᗘ࡞἞⒪ࢆ⾜࠺ࡓࡵࡢ୍ຓ࡜࡞ࢀࡤᖾ࠸࡛࠶ࡿࠋ
⩻ヂ⪅௦⾲ ⬥⏣᫂ᑦ

16

16

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)

Accelerator beam data commissioning equipment and procedures:
Report of the TG-106 of the Therapy Physics Committee of the AAPM
Indra J. Das

Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104

Chee-Wai Cheng

Department of Radiation Oncology, Morristown Memorial Hospital, Morristown, New Jersey 07962

Ronald J. Watts

International Medical Physics Services, San Antonio, Texas 78232

Anders Ahnesjö

Uppsala University and Nucletron Scandinavia AB, 751 47 Uppsala, Sweden

John Gibbons

Department of Radiation Oncology, Mary Bird Perkins Cancer Center, Baton Rouge, Louisiana 70809

X. Allen Li

Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226

Jessica LowensteinRadiological Physics Center, MD Anderson Cancer Center, Houston, Texas 77030

Raj K. Mitra

Department of Radiation Oncology, Ochsner Clinic, New Orleans, Louisiana 70121

William E. Simon

Sun Nuclear Corporation, Melbourne, Florida 32940

Timothy C. Zhu

Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104(Received 4 February 2008; revised 18 July 2008; accepted for publication 18 July 2008;
published 22 August 2008)ᗎᩥ་⒪⏝ຍ㏿ჾࡢࢥ࣑ࢵࢩࣙࣥࢢ࡟࠶ࡓࡾࠊ་Ꮫ≀⌮ኈࡣ༑ศ࡞⢭ᗘࡢᢸಖࠊᵝࠎ࡞ᐃἲࠊࢹ࣮ࢱࡢ᳨ドࠊᶆ‽ⓗ᪉ἲࡢ୙㊊ࠊ࠾ࡼࡧ᫬㛫ⓗไ⣙࡞࡝ከࡃࡢᅔ㞴࡟ᑐฎࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋࢥ࣑ࢵࢩࣙࢽࣥࢢࡋࡓࣅ࣮࣒
ࢹ࣮ࢱࡣ㸦௒ᚋࡢ QA/QC ࡟࠾ࡅࡿ㸧ᇶ‽࡜࡞ࡿ࡜࡜ࡶ࡟ࠊ᭱⤊ⓗ࡟ࡣ἞⒪ィ⏬⿦⨨㸦TPS㸧࡛⏝࠸ࡽࢀࡿࡓ
ࡵࠊࢹ࣮ࢱࡢ཰㞟ࡣ㧗࠸⢭ᗘ࡛⾜ࢃࢀࡿᚲせࡀ࠶ࡿࠋࡑ࠺ࡍࡿࡇ࡜࡛ᝈ⪅἞⒪࡟࠾ࡅࡿ⥺㔞ㄗᕪࢆపῶࡋࠊࡦ
࠸࡚ࡣᨺᑕ⥺἞⒪ࡢຠᯝࡢపୗࢆ㜵ࡄࡇ࡜ࡀ࡛ࡁࡿࠋࣅ࣮࣒ࢹ࣮ࢱࡢࢥ࣑ࢵࢩࣙࢽࣥࢢࡣ㐺ษ࡞▱㆑࡜ᶵჾࢆ
⏝࠸࡚⾜ࢃࢀࡿ࡭ࡁ࡛࠶ࡾࠊ ᐃ⪅࡟ࡼࡗ࡚␗࡞ࡿ⤖ᯝࢆ⏕ࡴࡇ࡜ࡀ࠶ࡗ࡚ࡣ࡞ࡽ࡞࠸ࠋࡇࢀࡽࢆ㐩ᡂࡍࡿࡓࡵ࡟ American Association of Physicists in Medicine㸦AAPM㸧ࡢ἞⒪≀⌮ጤဨ఍㸦Therapy Physics Committee㸧࡟࠾࠸࡚ࠊࣜࢽ࢔ࢵࢡࡢ≀⌮ⓗࢥ࣑ࢵࢩࣙࢽࣥࢢ࡜ྠᵝ࡟ࠊᐇ㊶ⓗ࡞ࣅ࣮࣒ࢹ࣮ࢱᐃࢆ᳨ウࡍࡿࡇ࡜ࢆ┠ⓗ࡜ࡋ࡚ࢱࢫࢡࢢ࣮ࣝࣉ㸦TG㸧106 ࡀ⤌⧊ࡉࢀࡓࠋࡇࡢ࣏࣮ࣞࢺ࡛ࡣࠊ㐺ษ࡞ࣇ࢓ࣥࢺ࣒࡜᳨ฟჾࡢ㑅ᢥࠊࢹ࣮ࢱ
ᐃࡢࡓࡵࡢࣇ࢓ࣥࢺ࣒ࡢࢭࢵࢺ࢔ࢵࣉἲ㸦ࢫ࢟ࣕࢽࣥࢢ࡜ࣀࣥࢫ࢟ࣕࢽࣥࢢ୧᪉㸧ࠊගᏊ⥺࣭㟁Ꮚ⥺ࡢලయⓗ࡞ࣅ࣮࣒ࣃ࣓࣮ࣛࢱྲྀᚓἲ࡜

ᐃㄗᕪࡢῶᑡ᪉ἲ㸦<1%㸧ࠊࣅ࣮࣒ࢹ࣮ࢱࡢຍᕤἲ࠾ࡼࡧṇ☜࡞ࣉࣟࣇ࢓࢖

ࣝࢆᚓࡿࡓࡵࡢ᳨ฟჾࢧ࢖ࢬࢥ࣮ࣥ࣎ࣜࣗࢩࣙࣥ࡞࡝࡟㛵ࡍࡿ࢞࢖ࢻࣛ࢖ࣥ࡜່࿌ࢆᥦ౪ࡍࡿࠋࡲࡓࠊࡇࡢ
TG-106 ࡛ࡣගᏊ⥺࣭㟁Ꮚ⥺ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ࡟࠾ࡅࡿࣔࣥࢸ࢝ࣝࣟࢩ࣑࣮ࣗࣞࢩࣙࣥἲࡢ㏆ᖺࡢࢺࣞࣥࢻ
࡟㛵ࡋ࡚ࡶ⡆₩࡟ㄽࡎࡿࠋࡇࡢ࣏࣮ࣞࢺ࡟グ㍕ࡉࢀࡓᡭἲࡣ་Ꮫ≀⌮ኈ࡟࡜ࡗ୍࡚㐃ࡢࣅ࣮࣒ࢹ࣮ࢱࡢ

ᐃࡸࠊ⮫ᗋ౑⏝๓࠾ࡼࡧᐃᮇⓗ࡞ QA ࡟࠾ࡅࡿࢹ࣮ࢱࡢ᳨ドࢆ⾜࠺࡟࠶ࡓࡗ࡚ᡭຓࡅ࡜࡞ࡿࡣࡎ࡛࠶ࡿࠋᐇ㊶࡜⌮ㄽࢆ⤌ࡳྜࢃࡏࡿࡇ࡜࡛ࠊࡇࡢ࣏࣮ࣞࢺࡣࣅ࣮࣒ࢹ࣮ࢱࢥ࣑ࢵࢩࣙࢽࣥࢢࡢ᪂ࡋ࠸ᶆ‽ࢆ୚࠼ࡿࡶࡢ࡛࠶ࡿࠋ

17

医学物理 第 33 巻 第 1 号

TABLE OF CONTENTS

III.E.3. 㐜ᘏ᫬㛫I. ࡣࡌࡵ࡟

III.E.4. ࢧࣥࣉࣜࣥࢢ᫬㛫࡜ಙྕ

I.A. ┠ⓗ

III.E.5. 㧗࿘Ἴࣀ࢖ࢬࡢᖸ΅

I.B. ⫼ᬒ

III.F. ࢹ࣮ࢱࣇ࢓࢖ࣝ

I.B.1. ࢹ࣮ࢱࢥ࣑ࢵࢩࣙࢽࣥࢢࡢᚲせᛶ

III.F.1. ࢹ࣮ࢱࣇ࢓࢖ࣝࡢᵓᡂ

I.B.2. ࣅ࣮࣒ࢥ࣑ࢵࢩࣙࢽࣥࢢ࡟㛵ࡍࡿၥ㢟

III.F.2. ࣇ࢓࢖ࣝࡢྡ๓

I.B.3. ࡇࡢࢱࢫࢡࢢ࣮ࣝࣉ࡟ࡘ࠸࡚
I.B.4. ࢥ࣑ࢵࢩࣙࢽࣥࢢࡢసᴗ㔞II. ࣇ࢓ࣥࢺ࣒ࡢᮦ㉁࡜౑⏝ἲࠊ᳨ฟჾ
II.A. ࣇ࢓ࣥࢺ࣒ᮦ㉁IV. ගᏊ⥺ࡢࣅ࣮࣒ࢹ࣮ࢱ
IV.A. ගᏊ⥺ࢫ࢟ࣕࣥࢹ࣮ࢱ
IV.A.1. ῝㒊⥺㔞
IV.A.2. ⤌⧊᭱኱⥺㔞ẚ࣭⤌⧊ࣇ࢓ࣥࢺ࣒⥺㔞

II.B. ࣇ࢓ࣥࢺ࣒ࡢᑍἲ

ẚ 㸦TMR/TPR㸧

II.C. ᅛయࣇ࢓ࣥࢺ࣒

IV.A.3. ⾲㠃⥺㔞࡜ࣅࣝࢻ࢔ࢵࣉ㡿ᇦ

II.D. ࣅࣝࢻ࢔ࢵࣉ࢟ࣕࢵࣉ

IV.A.4. ࣅ࣮࣒ࣉࣟࣇ࢓࢖ࣝ

II.E. ᳨ฟჾII.E.1. ྛ᳨ฟჾࡢ᭷⏝ᛶ

IV.B. MLC ࢹ࣮ࢱ
IV.C. ගᏊ⥺࣏࢖ࣥࢺ⥺㔞ࢹ࣮ࢱ

II.E.2. ᳨ฟჾࡢ✀㢮

IV.C.1. ඲ᩓ஘ಀᩘ 㸦Scp㸧

II.E.3. ᳨ฟჾࡢ㑅ᢥ

IV.C.2. ✵୰ฟຊಀᩘ 㸦Sc㸧

II.E.4. ᳨ฟჾࡢᛂ⟅࡜⿵ṇ

IV.C.3. ࣇ࢓ࣥࢺ࣒ᩓ஘ಀᩘ 㸦Sp㸧III. ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢࢭࢵࢺ࢔ࢵࣉ
III.A. ࢫ࢟ࣕࢼࡢ᳨ド࡜☜ㄆIII.A.1. ࢫ࢟ࣕࢽࣥࢢ㸦ࣇ࢕࣮ࣝࢻ㸧⥺㔞ィ࡜ࣜࣇ࢓ࣞࣥࢫ⥺㔞ィ
III.A.2. ࢣ࣮ࣈࣝࠊࢥࢿࢡࢱࠊ࢔ࢲࣉࢱ
III.A.3. 㟁఩ィ
III.B. ࢫ࢟ࣕࢽࣥࢢ⏝Ỉࢱࣥࢡ
III.B.1. ࣏ࢪࢩࣙࢽࣥࢢ࡜ࣛ࣋ࣜࣥࢢ

IV.C.4. ࢙࢘ࢵࢪಀᩘ
IV.C.5. ࢺࣞ࢖ಀᩘ
IV.C.6. ᑠ↷ᑕ㔝࡛ࡢ⪃៖V. 㟁Ꮚ⥺
V.A. 㟁Ꮚ⥺ࢫ࢟ࣕࣥࢹ࣮ࢱ
V.A.2. ࣉࣟࣇ࢓࢖ࣝ
V.B. 㟁Ꮚ⥺࣏࢖ࣥࢺ⥺㔞ࢹ࣮ࢱ
V.B.1. ࢥ࣮ࣥಀᩘ

III.B.3. ࢫ࢟ࣕࢽࣥࢢࡢ᪉ྥ

V.B.2. ࢝ࢵࢺ࢔࢘ࢺಀᩘ

III.C. ࢫ࢟ࣕࣥࡢ㥑ືᶵᵓ࡜ືࡁ

V.B.3. ௬᝿/ᐇຠ⥺※఩⨨

III.C.2. ㏿ᗘ࡜఩⨨ࡢ⢭ᗘ
III.C.3. ࣄࢫࢸࣜࢩࢫ
III.C.4. ⭉㣗㸦ࡉࡧ㸧
III.D.

ᐃ๓ࡢヨ㦂

III.D.1. ࢻࣛ࢖ࣛࣥ

ᐃ

V.A.1. ῝㒊⥺㔞III.B.2. ࢫ࢟ࣕࢼࡢ㥑ື

III.C.1. 㓄ิᆺ᳨ฟჾࡢ㔜㔞

V.B.4. ࣔࣥࢸ࣮࢝ࣝࣟ࣋ࢫࡢ⥺㔞ィ⟬ࡢࡓࡵࡢࢹ࣮ࢱVI. ࣅ࣮࣒ࢹ࣮ࢱࡢຍᕤ
VI.A. ࢹ࣮ࢱࡢຍᕤ࡜᧯స
VI.B. ࢫ࣒࣮ࢪࣥࢢ࣭࣑࣮ࣛࣜࣥࢢ࠾ࡼࡧࢧ࣐ࣛ
࢖ࢪࣥࢢ

III.D.2. ࢛࣮࢘ࢱࣛࣥ

VI.B.1. ᩘᏛ㛵ᩘ࡜ࣇ࢕ࣝࢱ

III.D.3. 㣬࿴ヨ㦂

VI.B.2. ࢫ࣒࣮ࢪࣥࢢ࡟࠾ࡅࡿࡺࡀࡳ

III.D.4. 㟁㞳య✚እຠᯝ
III.D.5. ࢚ࢿࣝࢠ࣮ᛂ⟅ᛶࡢヨ㦂
III.E. ࢹ࣮ࢱྲྀᚓ

18

ᐃ

VI.C. ࣀࣥࢫ࢟ࣕࣥࢹ࣮ࢱࡢຍᕤ
VII. ࡲ࡜ࡵ࡜່࿌
VII.A. ່࿌

III.E.1. ࢫ࢟ࣕࣥࣃ࣓࣮ࣛࢱࡢࣉࣟࢺࢥࣝ

VII.B. ὀព

III.E.2. ࢫ࢟ࣕࣥ㏿ᗘ

VII.C. ࢥ࣑ࢵࢩࣙࢽࣥࢢ࣏࣮ࣞࢺ

I. はじめにJpn. J. Med. Phys. Vol. 33 No. 1 (2013)

I. ࡣࡌࡵ࡟

⏝࡟⪏࠼࠺ࡿ෌⌧ᛶࢆಖࡗ࡚࠸ࡿ࡜࠸࠺᰿ᣐࡣ࡞

I.A. ┠ⓗ࠸࡜࠸࠺ࡇ࡜࡛࠶ࡿࠋ౛࠼ࡤࠊྠࡌබ⛠࢚ࢿࣝࢠ࣮

ࣅ࣮࣒ࢹ࣮ࢱࡢࢥ࣑ࢵࢩࣙࢽࣥࢢࡣࠊ㐺ษ࡞▱㆑ࢆࡶࡘ⿦⨨㛫࡛ࡶࠊࣅ࣮࣒ࣃ࣓࣮ࣛࢱ࡟ᕪࡀ⏕ࡌࡿ࡜ᶵჾ࡟ᇶ࡙࠸࡚⾜࠸ࠊ ᐃ⪅ࡸࢫ࢟ࣕࢽࣥࢢࢩࢫ

ࡇ࡜ࡀሗ࿌ࡉࢀ࡚࠸ࡿ 3-5ࠋ➨஧࡟ࠊࣜࢽ࢔ࢵࢡࡢᑟ

ࢸ࣒࡟౫Ꮡࡋ࡚ࡣ࡞ࡽ࡞࠸ࠋ ᐃ⪅࡟ࡼࡿࢹ࣮ࢱࡢ

ධ࠾ࡼࡧཷࡅධࢀࡢ㝿ࡢྛ᪋タ࡟࠾ࡅࡿኚ᭦㸦ࣅ࣮┦㐪ࡣྍ⬟࡞㝈ࡾᑠࡉࡃࡍࡿᚲせࡀ࠶ࡿ㸦<1%㸧ࠋ࣒࢚ࢿࣝࢠ࣮ࡢኚ᭦ࡸࠊࢫࢸ࢔ࣜࣥࢢࡢኚ᭦࡟ࡼࡿ

ࡇࢀࢆ㐩ᡂࡍࡿࡓࡵࠊࡇࡢ࣏࣮ࣞࢺ࡛ࡣࠊࣇ࢓ࣥࢺ

ࣉࣟࣇ࢓࢖ࣝࡢኚ໬࡞࡝㸧ࡣ͆golden͇ࣅ࣮࣒ࢹ࣮

࣒ࡢࢭࢵࢺ࢔ࢵࣉࠊ ᐃᢏ⾡ࠊࣇ࢓ࣥࢺ࣒࡜᳨ฟჾ

ࢱ࡟ࡣ཯ᫎࡉࢀ࡞࠸ࠋ➨୕࡟ࠊࢯࣇࢺ࢙࢘ࢵࢪࡢࣅ

ࡢ㑅ᢥࠊㄗᕪࡢせᅉ࠾ࡼࡧලయⓗ࡞ගᏊ⥺࣭㟁Ꮚ⥺࣮࣒≉ᛶࡣ jaw ࡢ㏿ᗘࣃ࣓࣮ࣛࢱ࡟ࡼࡾኚ໬ࡋࠊྛ

ࣅ࣮࣒ࢹ࣮ࢱ

᪋タ࡛ࡢ㏿ᗘࡢ┦㐪ࡀࢯࣇࢺ࢙࢘ࢵࢪࡢࣅ࣮࣒ࣉ

ᐃࡢࡓࡵࡢ່࿌ࢆ⾜࠸ࠊࣅ࣮࣒ࢹ࣮

ࢱࡢࢥ࣑ࢵࢩࣙࢽࣥࢢࢆᐜ᫆࡟ࡍࡿࡇ࡜ࢆ┠ⓗ࡜ࣟࣇ࢓࢖ࣝ࡟ᙳ㡪ࢆ୚࠼࠺ࡿࠋ➨ᅄ࡟ࠊ
͆golden͇ࢹࡋ࡚࠸ࡿࠋ࣮ࢱࡀಶࠎࡢࢳ࢙ࢵࢡ࡟࠾࠸࡚チᐜ࡛ࡁࡿ⤖ᯝࡔࡗࡓ࡜ࡋ࡚ࡶࠊ⮫ᗋࢭࢵࢺ࢔ࢵࣉ࡟࠾࠸࡚」ྜⓗ࡞

I.B. ⫼ᬒ࢚࣮ࣛࡀ⏕ࡲࢀࠊ⤖ᯝ࡜ࡋ࡚チᐜ࡛ࡁ࡞࠸ྍ⬟ᛶࡀ

I.B.1. ࢹ࣮ࢱࢥ࣑ࢵࢩࣙࢽࣥࢢࡢᚲせᛶ࠶ࡿࠋ᭱ᚋ࡟ࠊࣅ࣮࣒ࢹ࣮ࢱࢥ࣑ࢵࢩࣙࢽࣥࢢࢆ⾜ᨺᑕ⥺἞⒪ࡢຠᯝࡣࠊᝈ⪅࡬ᢞ୚ࡉࢀࡿ⥺㔞ࡢ⢭࠺ࡇ࡜ࡀࣜࢽ࢔ࢵࢡࡢᚭᗏⓗ࡞ࢳ࢙ࢵࢡ࡟ࡘ࡞ࡀ

ᗘ࡜┤᥋㛵㐃ࡋࠊࡑࢀࡽࡣ἞⒪ィ⏬ࡢࣉࣟࢭࢫ࡟౑

ࡾࠊၥ㢟ࢆⓎぢ࡛ࡁࡿྍ⬟ᛶࡀ࠶ࡿࡢ࡟ᑐࡋࠊ

⏝ࡍࡿࣅ࣮࣒ࢹ࣮ࢱࡢ⢭ᗘ࡟౫Ꮡࡍࡿࠋࡇࢀࡽࡢࢹ

㸦͆golden͇ࢹ࣮ࢱ࡟ᑐࡍࡿ㸧ᒁᡤⓗ࡞ࢳ࢙ࢵࢡ࡛ࡣ

࣮ࢱࡣࣜࢽ࢔ࢵࢡࡢᑟධ᫬࡟ྲྀᚓࡉࢀࡿࠋࡲࡓࠊࡑⓎぢ࡛ࡁ࡞࠸ࡇ࡜ࡶ⪃࠼ࡽࢀࡿ࡜࠸࠺ࡇ࡜࡛࠶ࡿࠋ

ࡢࢹ࣮ࢱࡣᇶ‽್࡜ࡋ࡚ᢅࢃࢀࠊ་Ꮫ≀⌮ኈࡣ
1ࡋ࠿ࡋ࡞ࡀࡽࠊᑡ࡞ࡃ࡜ࡶ͆golden͇ࢹ࣮ࢱࡣࣘ

TG-40 ࡟グ㍕ࡉࢀ࡚࠸ࡿࡼ࠺࡟ࠊᐃᮇⓗ࡟࣐ࢩ࣮ࣥࢨ࣮ࡀྲྀᚓࡋࡓࣅ࣮࣒ࢹ࣮ࢱࡢ᳨ド࡟ᑐࡍࡿ㠀ࣃ࣓࣮ࣛࢱࡀኚ໬ࡋ࡚࠸࡞࠸ࡇ࡜ࢆ☜ㄆࡍ࡭ࡁ࡛

ᖖ࡟ඃࢀࡓ QA ࡢཧ⪃ࢹ࣮ࢱ࡜࡞ࡿࠋࡇࢀࡽࡢࢹ࣮

࠶ࡿࠋࡲࡓࠊ἞⒪ィ⏬⿦⨨㸦TPS㸧ࡢィ⟬࢔ࣝࢦࣜࢱࡣ MD Anderson Cancer Center ࡟࠾ࡅࡿᨺᑕ⥺≀ࢬ࣒ࢆኚ᭦ࡍࡿሙྜ࡞࡝ࠊTPS ࡟ఱࡽ࠿ࡢኚ໬ࡀ࠶

⌮ࢭࣥࢱ࣮㸦Radiological Physics Center㸧࠿ࡽྲྀᚓྍ

2ࡗࡓሙྜ࡛ࡣࠊࢹ࣮ࢱࡢ㏣ຍࡀᚲせ࡛࠶ࡿ ࠋࣜࢽ࢔ࢵࢡࡢ〇㐀ᕤ⛬ࡀᏳᐃࡍࡿ࡟ࡘࢀ࡚ࠊ〇㐀⬟࡛࠶ࡾ 6-8ࠊ࣮ࣘࢨ࣮ࡣ⮬᪋タࡢࢹ࣮ࢱ࡜௚᪋タࡢ
ࢹ࣮ࢱࢆẚ㍑ࡋࠊྜ⌮ⓗ࡞⠊ᅖ୍࡛⮴ࡍࡿ࠿☜ㄆࡍᴗ⪅ࡣྠ୍ࡢࣅ࣮࣒≉ᛶࢆ♧ࡍࡼ࠺἞⒪⿦⨨ࢆᶆࡿࡇ࡜ࡀ࡛ࡁࡿࠋࣔࣥࢸ࢝ࣝࣟࢩ࣑࣮ࣗࣞࢩࣙࣥࡶ

‽໬ࡋࡼ࠺࡜ࡍࡿࠋTPS ࡟ᚲせ࡞࡯࡜ࢇ࡝ࠊ࠶ࡿ࠸

ࡲࡓࡼ࠸ᶆ‽ࢹ࣮ࢱࢆ୚࠼ࡿࠋࡋ࠿ࡋ࡞ࡀࡽࣔࣥࢸ

ࡣࡍ࡭࡚ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢࡉࢀࡓࣅ࣮࣒ࢹ࣮ࢱ

࢝ࣝࣟࢩ࣑࣮ࣗࣞࢩࣙࣥ࡟ࡼࡿࢹ࣮ࢱࡢ᳨ド࡟ࡣࠊࡀ͆golden͇ࣅ࣮࣒ࢹ࣮ࢱ࡜ࡋ࡚୚࠼ࡽࢀࡿሙྜࡶ

ᇶ‽࡜࡞ࡿ࠶ࡿࠋࣜࢽ࢔ࢵࢡ࡜ྠࡌ࣋ࣥࢲ࣮ࡀ TPS ࢆᥦ౪ࡋ࡚ᐃࡀᚲせ࡜࡞ࡿ 9-13ࠋ

ࡇࡢ࣏࣮ࣞࢺ࡛ࡣࣜࢽ࢔ࢵࢡࡢࢥ࣑ࢵࢩࣙࢽࣥ

࠸ࡿሙྜࠊ
͆golden͇ࣅ࣮࣒ࢹ࣮ࢱࡣࡍ࡛࡟ TPS ࡟ࢢ᫬࡟᥎ዡࡍࡿ

Ⓩ㘓ࡉࢀ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿࠋࡇࡢࡼ࠺࡞ሙྜࠊࣅ

࠸ࡀࠊᑡ࡞ࡃ࡜ࡶ௨ୗࡢ㡯┠ࡢࢹ࣮ࢱࡣྲྀᚓࡍࡿᚲ

࣮࣒ࢥ࣑ࢵࢩࣙࢽࣥࢢࡢ㝿࡟ࠊ࣮ࣘࢨ࣮ࡣᚲせ࡞ࡍ

せࡀ࠶ࡿࠋ࡭࡚ࡢࢹ࣮ࢱࢆ

ᐃ㡯┠࡟ࡘ࠸࡚ࡣグ㍕ࡋ࡚࠸࡞ᐃࡍࡿ࠿ࠊ࠶ࡿ࠸ࡣⓏ㘓ࡉࢀ࡚࠸ࡿࢹ࣮ࢱࢆὀព῝ࡃ᳨ドࡍࡿ࠿ࢆ㑅ᢥࡍࡿࡇ࡜ࡀxගᏊ⥺͐῝㒊㔞ⓒศ⋡㸦PDD㸧ࠊ࣮࢜ࣉࣥ࠾ࡼ

࡛ࡁࡿࠋ࡝ࡕࡽࢆ㑅ᢥࡍࡿࡇ࡜ࡀ㐺ᙜ࠿ࡣࠊࣜࢽ࢔

ࡧ࢙࢘ࢵࢪ↷ᑕ㔝ࡢ」ᩘࡢ῝ࡉ࡟࠾ࡅࡿࣉࣟ

ࢵࢡࡸ TPS ࡢࣔࢹࣝࠊ⮫ᗋ౑⏝࡟⪏࠼࠺ࡿ⢭ᗘࢆᣢࣇ࢓࢖ࣝ㸦in-plane ࠾ࡼࡧ cross-plane㸧ࠊMLC

ࡗ࡚࠸ࡿ࠿࡞࡝ࠊ࠸ࡃࡘ࠿ࡢせᅉ࡟౫Ꮡࡍࡿࡔࢁ࠺ࠋ

㛵㐃ࡢࢹ࣮ࢱ㸦intra/inter leaf leakage, MLC ༙ᙳ

ࡶࡋ͆golden͇ࣅ࣮࣒ࢹ࣮ࢱࢆ⮫ᗋ౑⏝ࡍࡿ࡞ࡽ㒊ࠊtongue & groove ຠᯝ࡞࡝㸧ࠊࢥ࣓࣮ࣜࢱᩓ

ࡤࠊ௨ୗࡢⅬࢆὀព῝ࡃホ౯ࡍࡿᚲせࡀ࠶ࡿࠋ➨୍஘ಀᩘࠊ඲ᩓ஘ಀᩘࠊࢺࣞ࢖ಀᩘࠊ࢙࢘ࢵࢪಀ

࡟ࠊ〇㐀ᕤ⛬࡟࠾࠸࡚ࡍ࡭࡚ࡢࣜࢽ࢔ࢵࢡࡀ⮫ᗋ౑ᩘࠋ

19

医学物理 第 33 巻 第 1 号

x

I. はじめに㟁Ꮚ⥺͐PDD, ࣉࣟࣇ࢓࢖ࣝ, ࢥ࣮ࣥಀᩘࠊ࢝
ࢵࢺ࢔࢘ࢺಀᩘࠊ௬᝿⥺※఩⨨ࠋࢥ࣑ࢵࢩࣙࢽࣥࢢࡣㄆᐃࡉࢀࡓ་Ꮫ≀⌮ኈ࡟ࡼࡗ࡚⾜ࢃࢀࡿᚲせࡀ࠶ࡿࠋࡇࡢ࣏࣮ࣞࢺ࡟グ㍕ࡉࢀ
ࡓᡭἲࡣࣅ࣮࣒ࢹ࣮ࢱࡢ

ᐃ࠾ࡼࡧ⮫ᗋ౑⏝๓ࡢࢹ࣮ࢱ☜ㄆࡸᐃᮇⓗQAࡢᇶ‽ࢹ࣮ࢱࢆ

ᐃࡍࡿ࠺

2

࠼࡛ᡭຓࡅ࡜࡞ࡿࡔࢁ࠺ࠋTG-53 ࡛グ㍕ࡉࢀ࡚࠸
ࡿTPS㛵㐃ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢヂ⪅ὀ 1࡟㛵ࡋ࡚ࡶ⪃៖ࡍ࡭ࡁ࡛࠶ࡿࠋ
I.B.2. ࣅ࣮࣒ࢥ࣑ࢵࢩࣙࢽࣥࢢ࡟㛵ࡍࡿၥ㢟ከࡃࡢࣅ࣮࣒ࢹ࣮ࢱ

ᐃࡣẚ㍑ⓗ༢⣧࡛࠶ࡿࡀࠊ

౑⏝ࡍࡿ᳨ฟჾࢩࢫࢸ࣒࡜ࣇ࢓ࣥࢺ࣒࡟ࡼࡗ࡚⤖ᯝࡀ኱ࡁࡃኚ໬ࡍࡿࡇ࡜ࡀ࠶ࡿࠋ᳨ฟჾࡣࢧ࢖ࢬ
㸦ᶆ‽ᆺࠊ࣑ࢽᆺࠊ࣐࢖ࢡࣟᆺ㸧ࠊࢱ࢖ࣉ㸦㟁㞳⟽࣭༙ᑟయ࡞࡝㸧ࠊᙧ≧㸦ᣦ㢌ᙧࠊ⌫ᙧࠊᖹ⾜ᖹᯈᙧ㸧࡞࡝ከࡃࡢ㑅ᢥ⫥ࡀ࠶ࡾࠊ㐺ษ࡞᳨ฟჾࡢ㑅ᢥ࡟ࡣᅔᝨࡉࡏࡽࢀࡿࠋࡶࡋ୙㐺ษ࡞᳨ฟჾࢆ㑅ᢥࡋࡓሙྜࠊ ᐃࡋࡓࣅ࣮࣒ࢹ࣮ࢱࡢ㉁ࡀపୗࡍࡿሙྜࡶ࠶
ࡿࠋ౛࠼ࡤ Fig.1 ࡣ 6 MV ࣅ࣮࣒ࡢᑠ↷ᑕ㔝ࠊᇶ‽↷ᑕ㔝㸦1010 cm2㸧ࠊ኱↷ᑕ㔝ࡢ PDD ࢆᵝࠎ࡞᳨ฟჾ࡛ྲྀᚓࡋࡓ⤖ᯝ࡛࠶ࡿࠋ᳨ฟჾ࡟ࡼࡗ࡚ᑠ↷ᑕ㔝࠾ࡼࡧ኱↷ᑕ㔝࡛チᐜ࡛ࡁ࡞࠸┦㐪ࡀ⏕ࡌ࡚࠸ࡿࠋ〇㐀ᴗ⪅ࡣཷࡅධࢀヨ㦂ࡢ㝿࡟࢞࢖ࢻࣛ࢖ࣥ࡜
チᐜ⠊ᅖࢆᥦ♧ࡍࡿࠋࡋ࠿ࡋࠊ἞⒪⿦⨨ࡢࢥ࣑ࢵࢩ
ࣙࢽࣥࢢࡣྛ᪋タࡢ་Ꮫ≀⌮ኈࡀ㈐௵ࢆࡶࡘᚲせࡀ࠶ࡿࠋ㐣ཤࡢࢱࢫࢡࢢ࣮ࣝࣉ 14, 15 ࡣཷࡅධࢀヨ㦂࡟ᑐࡍࡿ࢞࢖ࢻࣛ࢖ࣥࢆ♧ࡋ࡚࠸ࡿࡀࠊࣅ࣮࣒ࢹ࣮
ࢱࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ࡟ᑐࡋ࡚ࡣゝཬࡋ࡚࠸࡞࠸ࠋ
ཷࡅධࢀヨ㦂࡜ࢥ࣑ࢵࢩࣙࢽࣥࢢ࡟㛵ࡍࡿ᭱㏆ࡢᩥ⊩ 16 ࡛ࡣཷࡅධࢀヨ㦂࡟㛵ࡍࡿᵝࠎ࡞ഃ㠃࡟ࡘ

FIG. 1. Depth dose data for a 6 MV beam for (a) 1×1 cm2, (b) 10×10
cm2, and (c) 40×40 cm2 fields using different detectors.

࠸࡚ヲ⣽ࡀ㏙࡭ࡽࢀ࡚࠸ࡿࡀࠊࢥ࣑ࢵࢩࣙࢽࣥࢢ࡟
ࡘ࠸࡚ࡣゐࢀࡽࢀ࡚࠸࡞࠸ࠋཷࡅධࢀヨ㦂࡜ࢥ࣑ࢵࢩࣙࢽࣥࢢ࡟ࡘ࠸࡚ࠊㄗࡗࡓㄆ㆑ࡀ࠶ࡿࠋཷࡅධࢀ
ヨ㦂ࡣࠊ〇㐀ᴗ⪅ࡀᐃࡵࡿ࢞࢖ࢻࣛ࢖ࣥ࡟ᚑࡗ࡚⾜ࢃࢀࠊࣅ࣮࣒ࢹ࣮ࢱࡢ☜ㄆࡣࡈࡃࢃࡎ࠿࡛࠶ࡿࠋࡑ
ࢀ࡟ᑐࡋ࡚ࠊࢥ࣑ࢵࢩࣙࢽࣥࢢࡣࠊࡍ࡭࡚ࡢࣅ࣮࣒

ࢹ࣮ࢱࢆྲྀᚓࡋࠊࡑࡢࢹ࣮ࢱࡀᝈ⪅἞⒪࡟⏝࠸ࡽࢀࡿࠋ⮫ᗋ౑⏝ࡉࢀࡿ⥺㔞ࢹ࣮ࢱࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ
࡟㛵ࡋ࡚ࡣ࡯࡜ࢇ࡝ᩥ᭩໬ࡉࢀࡓ᝟ሗࡀ࡞࠸ࡢࡀ
⌧≧࡛࠶ࡿࠋ
I.B.3. ࡇࡢࢱࢫࢡࢢ࣮ࣝࣉ࡟ࡘ࠸࡚

ヂ⪅ὀ1ụ⏣⌜࡟ࡼࡿ࿴ヂࡀ JSMP ࣮࣒࣮࣍࣌ࢪୖ࡟
බ㛤ࡉࢀ࡚࠸ࡿࠋ

20ࡇࡢࢱࢫࢡࢢ࣮ࣝࣉࡣࠊࣜࢽ࢔ࢵࢡࡢࢥ࣑ࢵࢩࣙ

I. はじめにJpn. J. Med. Phys. Vol. 33 No. 1 (2013)

Table I. (a) Typical commissioning measurements for photon beam data for each energy and wedge. (b) Typical commissioning measurements forelectron beam data for each energy.
(a)Square field size (cm)Description

1

Application
PDD/TMR
Profiles @

Scan

2

3

4

5

6

IMRT data

8

10

12

14

16

20

25

30

Traditional radiation oncology fields

40

>40

Magna Field

×
×

×
×

×
×

×
×

×
×

×
×

×
×

×
×

×
×

×
×

×
×

×
×

×
×

×
×

×
×

×
×

×
×

×
×

×
×
×

×
×
×
×

×
×
×
×

×
×
×
×

×
×
×
×

×
×
×
×

×
×
×
×

×
×
×
×

×
×
×
×

×
×
×
×

×
×

×

×
×
×
×

×
×

×

×
×
×
×

×

×

5-7 depths

data

Diagonal orstar profiles
Sc
Sp

Nonscan

WF/TF

data

Surface dose(b)Cone size (cm×cm)
Description
PDD
Profiles @Scan data

5×5

10×10

15×15

20×20

25×25

×
×

×
×

×
×

×
×

×
×

×
×
×
×

×
×
×
×

×
×
×
×

×
×
×
×

×
×
×
×

5-7 depths
Cone factor
Nonscan

Cutout factor

data

Virtual source
Surface doseࢽࣥࢢ࡟㛵ࡍࡿ≀⌮ⓗ࡞஦㡯࡟ࡘ࠸࡚෌᳨ウࡋࠊ㐺࣮ࣝࣉ࠿ࡽࡑࢀࡽࡢࢱࢫࢡࢢ࣮ࣝࣉࡢ࣏࣮ࣞࢺ࡬

ษ࡞᳨ฟჾࠊࣇ࢓ࣥࢺ࣒ࠊ࠾ࡼࡧ

ᐃ᪉ἲࡢ࢞࢖ࢻ

┤᥋ཧ↷ࢆ⾜ࡗ࡚࠸ࡿࠋTG-106 ࡣ᳨ฟჾࠊࣇ࢓ࣥ

ࣛ࢖ࣥ࡜່࿌ࢆ♧ࡍࡇ࡜࡟ࡼࡾࠊ

ᐃㄗᕪࢆs1%ࢺ࣒ࠊᐃᶵჾ㸦㟁఩ィ㸧ࠊၟ⏝ࢩࢫࢸ࣒ࡢ㝈⏺࡜௨ୗ࡜ࡍࡿࡇ࡜ࢆ┠ⓗ࡜ࡋ࡚࠸ࡿࠋࡇࡢࢱࢫࢡࢢࣝ

⿵ṇ࡞࡝἞⒪⿦⨨ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ࡟ᑐࡍࡿ࢞

࣮ࣉࡣ gold standard ࢹ࣮ࢱࢆ୚࠼ࡿࡶࡢ࡛ࡣ࡞࠸ࡋࠊ

࢖ࢻࣛ࢖ࣥ࡜່࿌ࢆᥦ౪ࡍࡿࠋࡓࡔࡋࠊSRS 17ࠊ

≉ᐃࡢ TPS ࡟ᑐࡍࡿࢹ࣮ࢱ

Gamma KnifeࠊCyberKnifeࠊTotal Skin Electron Therapyᐃࢆྲྀࡾᢅ࠺ࡶࡢ࡛
ᐃࢆ࢝ࣂ࣮࡛ࡁࡿ㸦TSET㸧23ࠊTotal Body Irradiation㸦TBI㸧24 ࡞࡝ࡢࡼ࠺࡟ࡋ࡚࠸ࡿࠋࡇࡢࢱࢫࢡࢢ࣮ࣝࣉࡢㄢ㢟ࡣࠊࣅ≉Ṧ἞⒪ࡣ⠊ᅖእ࡜ࡋ࡚࠸ࡿࠋࡇࡢࢱࢫࢡࢢ࣮ࣝࣉ

࣮࣒≉᭷ࡢᛶ㉁ࢆ≉ᚩ࡙ࡅグ㘓ࡍࡿࠊ͆ࣅ࣮࣒ࢹ࣮

ࡣ㏻ᖖࡢࣜࢽ࢔ࢵࢡ࡟࠾ࡅࡿගᏊ⥺࡜㟁Ꮚ⥺ࡢࡳࢱࢥ࣑ࢵࢩࣙࢽࣥࢢ͇࡟ᑐࡍࡿᢏ⾡ࡸ᳨ฟჾࡢ㑅ᢥࢆᑐ㇟࡜ࡋ࡚࠸ࡿࠋ

ࡶ࡞࠸ࡀࠊ࡛ࡁࡿ㝈ࡾ࠶ࡽࡺࡿ

࡟ᑐࡋ࡚ᐃࡵࡽࢀ࡚࠸ࡿࠋ୍⯡࡟ࠊࡑࢀࡣࡇࡢᚋࡢ
సᴗ࡛࠶ࡿィ⟬࢔ࣝࢦࣜࢬ࣒ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ

I.B.4. ࢥ࣑ࢵࢩࣙࢽࣥࢢࡢసᴗ㔞࡛౑⏝ࡉࢀࡿࠋ୙ᆒ㉁⿵ṇ࡟㛵ࡋ࡚ࡶࠊ⌧௦ࡢ࢔ࣝᚲせ࡜ࡉࢀࡿࢥ࣑ࢵࢩࣙࢽࣥࢢࢹ࣮ࢱࡢ㔞ࡣࣘࢦࣜࢬ࣒㸦ࣔࣥࢸ࢝ࣝࣟࠊconvolution/superposition㸧࣮ࢨ࣮ࡢ⮫ᗋⓗᚲせᛶࠊTPSࠊMU ィ⟬ࣉࣟࢢ࣒ࣛࠊ

࡟࠾ࡅࡿ㔜せ࡞ഃ㠃࡛࠶ࡿࡀࠊࡇࡢ✀ࡢࢥ࣑ࢵࢩࣙ᪋タෆ࡛ᚲせ࡞ࢹ࣮ࢱࢸ࣮ࣈࣝ࡞࡝࡟ࡼࡗ࡚ኚ໬

ࢽࣥࢢࡣᐇ᪋ࡍࡿࡢࡀࡼࡾᅔ㞴࡛࠶ࡾࠊTPS ࡟౫ᏑࡍࡿࠋTable I㸦a㸧࠾ࡼࡧ㸦b㸧ࡣගᏊ⥺࡜㟁Ꮚ⥺࡟ࡍࡿࠋࡑࢀࡺ࠼ࡇࡢࢱࢫࢡࢢ࣮ࣝࣉ࡛ࡣ୙ᆒ㉁⿵ṇᑐࡍࡿ࡟㛵ࡋ࡚ࡣ⠊ᅖእ࡜ࡋࠊ௒ᚋࡢࢱࢫࢡࢢ࣮ࣝࣉ᳨࡛

40 × 40 cm2ࠊ῝ࡉ 0 ࠿ࡽ 40 cm ࡞࡝ᖜᗈ࠸ࢹ࣮ࢱࢆࠊウࡍࡿࡇ࡜࡜ࡍࡿࠋࡲࡓࠊูࡢࢱࢫࢡࢢ࣮ࣝࣉ㸦SRS

1-3 ✀㢮ࡢගᏊ⥺࢚ࢿࣝࢠ࣮࠾ࡼࡧ 0-8 ✀㢮ࡢ㟁Ꮚ

17⥺࢚ࢿࣝࢠ࣮࡟ᑐࡋ࡚⾜࠺ᚲせࡀ࠶ࡾࠊࣜࢽ࢔ࢵࢡ

ࠊIMRT

18,19

20

ࠊ࣊ࢵࢻᩓ஘㸦TG-74 㸧ࠊࣇ࢕࣒ࣝࢻ
2122ᐃ㡯┠ࡢ୍౛࡛࠶ࡿࠋ↷ᑕ㔝 1 × 1 cm2 ࠿ࡽࠊ㟁Ꮚ⥺㸦TG-70 㸧࡞࡝㸧࡜ࢩ࣓ࢺࣜ㸦TG-69 㸧ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ㔞ࡣⳘ኱࡛࠶ࡿࠋྲྀᚓࡍ࡭ࡁࢹ

㔜」ࡍࡿෆᐜࡶ࠶ࡿࠋᚲせ࡟ᛂࡌ࡚ࠊࡇࡢࢱࢫࢡࢢ

࣮ࢱ㔞࡜ࠊ≀⌮ࢫࢱࢵࣇࡢປാ㔞ࢆ⪃៖ࡋ࡚ࣅ࣮࣒

21

医学物理 第 33 巻 第 1 号

ࢹ࣮ࢱII. ファントムの材質と使用法、検出器ᐃࡢ᫬㛫ࢆỴᐃࡍࡿࡇ࡜ࡣ㔜せ࡛࠶ࡾࠊࢹ

࣑ࢵࢩࣙࢽࣥࢢࡢ୍㒊ࢆ࢝ࢵࢺࡋ࡚᫬㛫ࢆ๐ῶࡍ࣮ࢱࡢྲྀᚓ᫬㛫ࡢぢ✚ࡶࡾࡣ἞⒪⿦⨨ࡢཷࡅධࢀ

ࡿࡇ࡜ࡣྍ⬟࡛࠶ࡿࠋ㸦ࢫ࢟ࣕࢽࣥࢢ࡟࠾ࡅࡿ㸧࣏ࡼࡾࡶ๓࡟⾜࠺ᚲせࡀ࠶ࡿࠋ୍౛࡜ࡋ࡚ࠊ2 ࡘࡢග࢖ࣥࢺᏊ⥺࢚ࢿࣝࢠ࣮࡟ᑐࡋ࡚ࠊ6 ࡘࡢࢫ࢟ࣕࢽࣥࢢࢹ࣮ቑຍࠊ ᐃ㛫ࡢ㐜ᘏ᫬㛫ࡢ๐ῶ࡞࡝࡟ࡼࡗ࡚ࡶ඲య

ࢱࢭࢵࢺ㸦1 ࡘࡢ PDDࠊ5 ࡘࡢ῝ࡉ࡛ࡢࣉࣟࣇ࢓࢖

ࡢ᫬㛫ࢆῶࡽࡍࡇ࡜ࡀ࡛ࡁࡿࠋࡋ࠿ࡋ࡞ࡀࡽࠊ᫬㛫ࣝ㸧ࢆ 15 ࡢ↷ᑕ㔝ࢧ࢖ࢬ࡛ࠊ5 ࡘࡢ᮲௳㸦࣮࢜ࣉࣥࠊ

๐ῶࡢࡓࡵࡢࢫ࢟ࣕࢽࣥࢢࣃ࣓࣮ࣛࢱࡢኚ᭦ࡣࣅ

4 ࡘࡢ≀⌮࢙࢘ࢵࢪ㸧࡟ᑐࡋ࡚ྲྀᚓࡍࡿሙྜࠊᘧ(1)࣮࣒ࢹ࣮ࢱࡢ㉁࡟ᙳ㡪ࢆ୚࠼ࡿࠋᐇ㝿࡟ࡇࢀࡽࢆ⾜ࡢࡼ࠺࡟᫬㛫ࡀぢ✚ࡶࡽࢀࡿࠋ

࠺๓࡟ࠊ኱↷ᑕ㔝ࡢࣉࣟࣇ࢓࢖ࣝ

ᐃࡢ཰㞟᫬㛫ࡢ▷⦰ࠊࢫ࢟ࣕࢽࣥࢢ㏿ᗘࡢᐃ࡞࡝ࡢࢸࢫࢺ

ࢫ࢟ࣕࣥࢆ⾜࠸ࠊࣅ࣮࣒ࢹ࣮ࢱ࡟ㄗᕪࢆ⏕ࡌ࡞࠸ࡇTime 㹼 [ (PDD + 5 Profiles) / beam energy]×࡜ࢆ☜ㄆࡍࡿᚲせࡀ࠶ࡿࠋ(open + 4 wedges) × (60 points/scan)II. ࣇ࢓ࣥࢺ࣒ࡢᮦ㉁࡜౑⏝ἲࠊ᳨ฟჾ

× [1 s/pts + 1 s (movement and delay) ]5

II.A. ࣇ࢓ࣥࢺ࣒ᮦ㉁× 15 fields × 2 energies㹼9 × 10 s㹼30 h.
(1)ࢥ࣑ࢵࢩࣙࢽࣥࢢࡢ㝿࡟ᐃࡍࡿࣅ࣮࣒ࢹ࣮ࢱ

ࡣ Table I ࡟♧ࡍࡼ࠺࡟㸦i㸧ࢫ࢟ࣕࣥࢹ࣮ࢱࠊ㸦ii㸧ᶵჾࡢࢭࢵࢺ࢔ࢵࣉࠊ⿦⨨ࣃ࣓࣮ࣛࢱࡢኚ᭦ࠊ⿦

ࣀࣥࢫ࢟ࣕࣥࢹ࣮ࢱ㸦࣏࢖ࣥࢺࢹ࣮ࢱ㸧ࡢ 2 ㏻ࡾࡀ

⨨ࡢࢺࣛࣈࣝ࡞࡝ࢆ⪃៖ࡍࡿ࡜ࠊගᏊ⥺ࢫ࢟ࣕࢽࣥ

Ꮡᅾࡍࡿࠋ࣏࢖ࣥࢺࢹ࣮ࢱࡣᅛయࣇ࢓ࣥࢺ࣒㸦ᚋ㏙㸧

ࢢࢹ࣮ࢱࡢྲྀᚓ࡟ᚲせ࡞᫬㛫ࡣ୍⯡ⓗ࡟ 1.5 㐌㛫࡛ࡶࡋࡃࡣỈࣇ࢓ࣥࢺ࣒ࢆ⏝࠸࡚࠶ࡿࠋࡶ࠺ 1 㐌㛫ࡣ࣏࢖ࣥࢺࢹ࣮ࢱࡢྲྀᚓ࡟㈝ࡸࡋࠊ

ࡁࡿࠋࢫ࢟ࣕࣥࢹ࣮ࢱࡢྲྀᚓࡣࢫ࢟ࣕࢽࣥࢢỈࣇ࢓

1-2 㐌㛫ࢆ㟁Ꮚ⥺ࠊṧࡾ 1 㐌㛫ࡣ᳨ド࡟ᚲせ࡜࡞ࡿࠋࣥࢺ࣒ࢆ⏝࠸࡚⾜ࢃࢀࠊ୍⯡࡟ 40 cm ῝ࡲ࡛ࡢ୰ᚰ

ࡲࡓࠊ୍⯡ⓗ࡟ゎᯒ࠾ࡼࡧ࣏࣮ࣞࢺࡢసᡂ࡟ࡣ 1-2㍈ PDD ࡜ࣉࣟࣇ࢓࢖ࣝࢆ㐌㛫ࢆせࡍࡿࠋࡇࢀࡽࢆྜィࡍࡿ࡜ࢥ࣑ࢵࢩࣙࢽࣥ

ࡿࠋࡇࢀࡽ࡟ࡣ 2 ḟඖ࠶ࡿ࠸ࡣ 3 ḟඖỈࣇ࢓ࣥࢺ࣒

ࢢ࡟๭ࡾᙜ࡚ࡽࢀࡿ᫬㛫ࡣ 4-6 㐌㛫࡜࡞ࡿࠋࡋ࠿ࡋ

࡞࡝࠸ࡃࡘ࠿ࡢࣂ࢚࣮ࣜࢩࣙࣥࡀ࠶ࡿࠋỈ㸦ࢫ࢟ࣕ࡞ࡀࡽࠊࣀࣥࢫ࢟ࣕࣥࢹ࣮ࢱࡢྲྀᚓࠊQA ࡢࡓࡵࡢࢽࣥࢢ㸧ࢱࣥࢡࡣᑡ࡞ࡃ࡜ࡶ 40 × 40 cm2 ࡢ↷ᑕ㔝ࢆᇶ‽ࢹ࣮ࢱࡢྲྀᚓࠊ࣋ࣥࢳ࣐࣮ࢡヨ㦂ࠊTPS ࢹ࣮ࢱ

40 cm ῝࡛ࡢ᳨ド࡞࡝࡟㏣ຍࡢ᫬㛫ࢆぢ✚ࡶࡿᚲせࡀ࠶ࡿࠋࢥ

୙༑ศ࡛࠶ࡾ౑⏝ࡍ࡭ࡁ࡛࡞࠸ࠋࡲࡓࠊගᏊ⥺࡟ᑐ࣑ࢵࢩࣙࢽࣥࢢ࡟チࡉࢀࡓ᫬㛫ෆ࡛ࡍ࡭࡚ࡢࢹ࣮

ࡍࡿࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣ cross-plane ࡜ in-planeࢱࢆྲྀᚓࡍࡿᚲせࡀ࠶ࡿࡓࡵࠊ࡜ࡾࢃࡅ᭱ప㝈ࡢ≀㸦x ᪉ྥ࡜ y ᪉ྥ㸧ࡢ୧᪉ࡢࢫ࢟ࣕࣥࡀ࡛ࡁࡿᚲせ⌮ࢧ࣏࣮ࢺࡋ࠿ᚓࡽࢀ࡞࠸᪋タ࡛ࡣࠊ≀⌮ࢫࢱࢵࣇࡀ࠶ࡿࠋ୧᪉ྥ࡟ࢫ࢟ࣕࣥࡀྍ⬟࡛࠶ࡿࡇ࡜࡛ࠊ⡆ࡣᅔ㞴ࢆᙉ࠸ࡽࢀࡿࡔࢁ࠺ࠋᑡᩘࡢ≀⌮ኈࡀ㎿㏿࡟

౽࡟ࢹ࣮ࢱྲྀᚓ࡛ࡁࠊࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢᅇ㌿࡟ࢹ࣮ࢱࢆྲྀᚓࡋࡼ࠺࡜ࡍࢀࡤࠊࢹ࣮ࢱࡢ㉁࡟ᙳ㡪ࡍࡼࡿ࢔ࣛ࢖࣓ࣥࢺ࢚࣮ࣛࢆ㑊ࡅࡿࡇ࡜ࡀ࡛ࡁࡿࠋ

ࡿྍ⬟ᛶࡀ࠶ࡿࠋ

TPS ࡟ࡼࡗ࡚ࡣ jaw ࡟ࡼࡿ↷ᑕ㔝ࡢࢹ࣮ࢱࡔࡅࡀᚲ

ࡶࡋྠࢱ࢖ࣉ࡛ࣅ࣮࣒≉ᛶࢆྜࢃࡏ㎸ࢇࡔ」ᩘ
ࡢ⿦⨨ࡀ࠶ࢀࡤࠊ Marshall ࡽ

25ࡀሗ࿌ࡋ࡚࠸ࡿࡼ

࠺࡟ప࢚ࢿࣝࢠ࣮ࣅ࣮࣒࡟㛵ࡋ࡚ࡣࠊࣅ࣮࣒ࢹ࣮ࢱ
ࡣࡼࡃ୍⮴ࡍࡿࡣࡎ࡛࠶ࡿࠋࡋ࠿ࡋ࡞ࡀࡽࠊ⌧௦ࡢᐃࡍࡿࡇ࡜ࡀ࡛

ᐃࡍࡿࡇ࡜ࡀྍ⬟࡛࠶ᐃ࡛ࡁࡿࡶࡢ࡛࡞ࡅࢀࡤࠊᩓ஘᮲௳ࡀ

せ࡛ࠊMLC ࡣ TPS ࡢෆ㒊࡛ࣔࢹࣜࣥࢢࡉࢀ࡚࠸ࡿ
ࡇ࡜ࡀ࠶ࡿࠋࡋ࠿ࡋ࡞ࡀࡽ MLC ↷ᑕ㔝ࡢࢹ࣮ࢱࡣ
ࣔࢹࣝࡢ᳨ドࡢࡓࡵ࡟ࡸࡣࡾᚲせ࡛࠶ࡿࠋ㈓Ỉࢱࣥࢡ࡟Ỉࡀ㈓ࡵ࡚࠶ࡾࠊࢫ࢟ࣕࢽࣥࢢࢱࣥ

⿦⨨࡟࠾ࡅࡿᐃ㔞ⓗ࡞ホ౯࡛ࡣ 1 ḟඖࡢ࣐࢞ࣥゎᯒࢡ࡟Ỉࢆ࣏ࣥࣉ࡛ࡃࡳୖࡆࡿࡼ࠺࡞ࢩࢫࢸ࣒ࡢሙ

࡛ࠊ2 ྎࡢྠ✀ࡢ⿦⨨࡟࠾࠸࡚ࠊྠ᮲௳࡛ྲྀᚓࡋࡓ

ྜࠊ㥑ື⣔࡟⸴㢮ࡀⓎ⏕ࡋ࡞࠸ࡼ࠺ẅ⳦๣ࢆᢞ୚ࡋ

」ᩘࡢࣉࣟࣇ࢓࢖ࣝࡢ࠺ࡕࠊ30%ࡀṇ☜࡟ࡣ୍⮴ࡋࡓ⵨␃Ỉࢆ౑࠺ᚲせࡀ࠶ࡿࠋࡶࡋ㈓Ỉࢱࣥࢡࡀ౑࠼

26࡞࠸ࡇ࡜ࡀ♧ࡉࢀ࡚࠸ࡿ ࠋ㐺ษ࡞ゎᯒ࡟ࡼࡿࢧࣥ

࡞࠸ሙྜࠊỈ

ࣉࣝࢹ࣮ࢱࡢẚ㍑⤖ᯝࡀ᪋タෆ࡛ࡢチᐜ್㸦ᇶᮏⓗ࡟ࡣᐊ࡜ྠ➼࡟ࡍࡿᚲせࡀ࠶ࡿࠋ࠸ࡃࡘ࠿ࡢ᳨ฟ

࡟ࡣӌs1%㸧ࢆ‶ࡓࡏࡤࠊྠ୍⿦⨨࡟ᑐࡋ࡚ࡢࡳࢥ

ჾ࡛ࡣᗘ࡟ᑐࡍࡿ⿵ṇࡀ༑ศ⪃៖ࡉࢀ࡚࠸࡞࠸

22ࢆࣔࢽࢱࣜࣥࢢࡋ࡚ࠊࢹ࣮ࢱ

ᐃ๓

II. ファントムの材質と使用法、検出器

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)

࡟㏆௜ࡅࡿࡇ࡜ࢆ᥎ዡࡍࡿ 27ࠋࡓࡵࠊ࡛ࡁࡿ㝈ࡾᐊࡑࡢࡓࡵࠊᐊ

࡜ᖹ⾮≧ែ࡟࡞ࡿࡼ࠺Ỉࢆࡋࡤࡽࡃ

ᐊෆ࡟⨨࠸࡚࠾ࡃᚲせࡀ࠶ࡿࠋ㌿ࡉࡏ࡚ࢹ࣮ࢱࢆྲྀᚓࡍࡿᚲせࡀ࠶ࡿࠋ୍⯡ⓗ࡟ࢥ࣓࣮ࣜࢱࢆᅇ㌿ࡉࡏ࡚ࡶࣇࣛࢵࢺࢽࣥࢢࣇ࢕ࣝࢱ
ࡢᙧ≧᝟ሗࡣᚓࡽࢀ࡞࠸ࡓࡵࠊࢥ࣓࣮ࣜࢱᅇ㌿࡟ࡼࣅ࣮࣒ࢫ࢟ࣕࢽࣥࢢࡣ୍⯡ⓗ࡟ᩘ᪥㛫௨ୖ࠿࠿ࡗ࡚ࡇࢀࡽࡢࢹ࣮ࢱࢆྲྀᚓࡋ࡚ࡣ࡞ࡽ࡞࠸ࠋ

ࡿࡓࡵࠊ⸴㢮ࡀⓎ⏕ࡋ࡚ࣅࣝࢻ࢔ࢵࣉࢆᙧᡂࡍࡿࡇ

ᑐゅ⥺᪉ྥࡢࣉࣟࣇ࢓࢖࡛ࣝࡣ 75 × 75 cm2 ࡼࡾ࡜ࡀ࠶ࡿࠋࡇࢀࡣࢱࣥࢡෆࡢỈࡀ㏱᫂࠿ࡽ᭎ࡗࡓ≧኱ࡁ࡞ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡀዲࡲࡋ࠸ࡀࠊ⌧ᐇ࡟ࡣែ࡟ኚ໬ࡍࡿࡇ࡜ࡀ♧၀ࡢ 1 ࡘ࡜࡞ࡿࠋࡈࡃᑡ㔞ࡢ

SSD = 100 cmࠊ30 cm ῝௨ୖࠊ↷ᑕ㔝 40 × 40 cm2 ࡜Ὑ๣ࡸሷ⣲ࢆຍ࠼ࡿࡇ࡜࡛⸴㢮ࢆຠᯝⓗ࡟㝖ཤ࡛࠸࠺᮲௳ࡢᑐゅ⥺᪉ྥࣉࣟࣇ࢓࢖ࣝ+5 cm ࡢ࣮࢜ࣂࡁࡿࠋࡇࢀࡽࡣ

࣮ࢫ࢟ࣕࣥࢆ

ᐃࢆ㛤ጞࡍࡿ๓࠿ࠊỈࡀ⃮ࡾࡔࡋᐃ࡛ࡁࡿၟ⏝ࡢࢫ࢟ࣕࢽࣥࢢࢩࢫ

ࡓࡽ༶ᗙ࡟⾜࠺ᚲせࡀ࠶ࡿࠋὙ๣ࢆຍ࠼ࡿࡇ࡜ࡢࡶ

ࢸ࣒ࡣ࡯࡜ࢇ࡝Ꮡᅾࡋ࡞࠸ࠋጇ༠Ⅼ࡜ࡋ࡚ࠊ↷ᑕ㔝࠺୍ࡘࡢ฼Ⅼࡣ⾲㠃ᙇຊࢆῶᑡࡉࡏࠊࢭࢵࢺ࢔ࢵࣉ

ࡢ∦ഃ༙ศࡢࡳࢆࢫ࢟ࣕࣥࡍࡿ᪉ἲ㸦ࣁ࣮ࣇࢫ࢟ࣕ

᫬ࡢ᳨ฟჾ఩⨨ࢆどぬⓗ࡟ࢃ࠿ࡾࡸࡍࡃ࡛ࡁࡿⅬࣥ㸧ࡀ࠶ࡿࡀࠊࣁ࣮ࣇࢫ࡛࢟ࣕࣥࡣ᭱኱↷ᑕ㔝࡛࠶ࡿࠋከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢ〇㐀ᴗ⪅ࡣ࡟ᑐࡋ࡚୰ᚰ㍈࡟࢜ࣇࢭࢵࢺࢆຍ࠼࡚

ࣁ࣮ࢻ࢙࢘࢔ࢆಖㆤࡍࡿࡓࡵࡢ⸆ရࢆᥦ౪ࡋ࡚࠸

ࢀࡤ࡞ࡽ࡞࠸ࠋࣁ࣮ࣇࢫ࢟ࣕࣥࢆ⾜࠺๓࡟ࠊ࣮࢜ࣉ

ࡿࠋࣥ↷ᑕ㔝ࡢ㠀ᑐ⛠ᛶࡀ 0.5%௨ୗ࡛࠶ࡿࡇ࡜ࢆ☜ㄆ

ᐃ

ᐃࡋ࡞ࡅ

ຍ࠼࡚ࠊࢫ࢟ࣕࢽࣥࢢࢹ࣮ࢱྲྀᚓ୰ࡢỈࡢ⵨Ⓨࡶࡍࡿࡇ࡜࡟ࡼࡾࠊ࣑࣮ࣛࢥࣆ࣮ࡋࡓࢹ࣮ࢱࡀ඲యࢆ

୍⯡ⓗ࡞ၥ㢟࡛࠶ࡿࠋࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢ኱ࡁࡉ

⾲ࡋ࡚࠸ࡿ࡜ࡳ࡞ࡍࡇ࡜ࡀ࡛ࡁࡿࠋࡲࡓࠊࡼࡾ῝࠸࡟ࡶࡼࡿࡀࠊỈࡢ⵨Ⓨࡣ᫬࡟↓ど࡛ࡁ࡞࠸࡯࡝᳨ฟ

㡿ᇦ࡛ࡣᶓ᪉ྥࡢᩓ஘ࢆ༑ศ࡟⪃៖ࡍࡿࡓࡵࠊࣁ࣮ჾࡢ῝ࡉࢆኚ࠼࡚ࡋࡲ࠺ࡇ࡜ࡀ࠶ࡿࡢ࡛ࠊ≉࡟㛗ᮇࣇࢫ࢟ࣕࣥ᫬࡟ࡣ୰ᚰ㍈ࡼࡾ᭱ప࡛ࡶ+5 cm ཯ᑐഃ㛫࡟ཬࡪࢫ࢟ࣕࢽࣥࢢ࡛ࡣࠊᐃᮇⓗ࡟Ỉ㠃ࢆ☜ㄆࡍࡲ࡛ࢫ࢟ࣕࣥࡍࡿࡇ࡜ࡀ᥎ዡࡉࢀࡿࠋࣁ࣮ࣇࢫ࢟ࣕ

ࡿࡇ࡜ࢆ᥎ዡࡍࡿࠋࣅ࣮࣒ࢫ࢟ࣕࢽࣥࢢࢆ⤊஢ࡋࡓࣥࡣࢭࢵࢸ࢕ࣥࢢ࡟ࡼࡾ㛗࠸᫬㛫ࢆせࡍࡿࠋTPS ࡢ㝿ࡣࠊࢫ࢟ࣕࢽࣥࢢࢱࣥࢡෆࡢỈࢆ᏶඲࡟᤼ฟࡋ஝

せ௳࡟ࡼࡿࡀࠊࢫ࢟ࣕࣥࡢ᏶඲࡞ࢹ࣮ࢱࢭࢵࢺࢆస

⇱ࡉࡏࡿᚲせࡀ࠶ࡿࠋ᫬࡟ࡣࢫ࢟ࣕࢽࣥࢢࡢࣁ࣮ࢻ

ᡂࡍࡿࡓࡵ࡟ࢹ࣮ࢱ᧯సࡀᚲせ࡟࡞ࡿሙྜࡶ࠶ࡿࠋ

࢙࢘࢔࡟ᑐࡋᑡ㔞ࡢ࢜࢖ࣝࢆὀࡍᚲせࡀ࠶ࡿሙྜ

᫬㛫๐ῶࢆ⾜࠺࡟ࡋ࡚ࡶࠊධຊࢹ࣮ࢱ࡜ࡋ࡚ࢩࢫࢸ

ࡶ࠶ࡿࠋ࣑ࢿࣛࣝỿ╔ࡸ⸴㢮ࡢⓎ⏕ࡣࣁ࣮ࢻ࢙࢘࢔

࣒㸦TPS㸧࡟㐺ྜࡋࡓࢹ࣮ࢱ࡛࠶ࡿ࠿☜ㄆࡍࡿᚲせࡢࢲ࣓࣮ࢪ࡜࡞ࡿࡓࡵࠊࢫ࢟ࣕࢽࣥࢢࢱࣥࢡෆ࡟Ỉࡀ࠶ࡿࠋࢆṧࡉ࡞࠸ࡇ࡜ࢆ᥎ዡࡍࡿࠋ
II.C. ᅛయࣇ࢓ࣥࢺ࣒
II.B. ࣇ࢓ࣥࢺ࣒ࡢᑍἲ

࣏࢖ࣥࢺ⥺㔞࠾ࡼࡧࣀࣥࢫ࢟ࣕࣥࢹ࣮ࢱ㸦ฟຊಀࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢࢧ࢖ࢬࡣ᭱኱↷ᑕ㔝ࡢࣉࣟࣇ࢓࢖ࣝᐃ࡟ᑐࡋ࡚༑ศ኱ࡁ࠸ᚲせࡀ࠶ࡿ㸦ග
2ᩘࠊ⾲㠃⥺㔞ࠊ₃࠼࠸/㏱㐣
ࣞ࢖ಀᩘ࡞࡝㸧ࡢᐃࠊ࢙࢘ࢵࢪ࠾ࡼࡧࢺ

ᐃࡣỈࣇ࢓ࣥࢺ࣒࡛ྍ⬟࡛ࠊከᏊ⥺࡛ࡣ 40 × 40 cm ࡟ຍ࠼࡚༑ศ࡞ഃ᪉ࣅࣝࢻ࢔

ࡃࡢሙྜࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࢆ⏝࠸࡚⾜ࢃࢀࡿࢵࣉ㸦5 cm㸧࡜࣮࢜ࣂ࣮ࢫ࢟ࣕࣥ㊥㞳ࢆྵࡵࡓࢧ࢖

ࡀࠊỈࢆᶍᨃࡋࡓᅛయࣇ࢓ࣥࢺ࣒ࡶ⡆౽ᛶ࠿ࡽ⏝࠸ࢬ㸧ࠋTPS ࡟ࡼࡗ࡚ࡣࠊࣔࢹࣜࣥࢢࡢࡓࡵ࡟᭱኱↷ࡿࡇ࡜ࡀ࡛ࡁࡿࠋ࢔ࢡࣜࣝࡸ࣏ࣜࢫࢳࣞࣥ࡞࡝Ỉ௨ᑕ㔝࠿ࡘ 40 cm ῝࡛ᶓ᪉ྥ࡟ࡼࡾ኱ࡁ࡞ࢫ࢟ࣕࣥࡸࠊ

እࡢࣉࣛࢫࢳࢵࢡ⣲ᮦࡣ Table II ࡸ௚ࡢᩥ⊩ 28, 29 ࡟ᑐゅ⥺᪉ྥࡢࢫ࢟ࣕࣥࢆᚲせ࡜ࡍࡿሙྜࡶ࠶ࡿࠋ㐺♧ࡍࡼ࠺࡟㟁Ꮚ⃰ᗘࠊ㜼Ṇ⬟㸦S㸧ࠊ㉁㔞࢚ࢿࣝࢠ࣮

ษ࡞ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࢧ࢖ࢬࢆỴᐃࡍࡿࡓࡵࠊ࢜

྾཰ಀᩘ㸦Pen/U㸧࡞࡝ࡀ␗࡞ࡾ⿵ṇࡀᚲせ࡛࠶ࡿࡓ࣮ࣂ࣮ࢫ࢟ࣕࣥ㡿ᇦ࡜ 40 cm ῝࡛ࡢࣅ࣮࣒ࡢᗈࡀࡾ

ࡵࠊὀពࡋ࡚౑⏝ࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋTello 29 ࡽࡣࠊࢆ⪃៖ࡍࡿᚲせࡀ࠶ࡿࠋ᭱኱↷ᑕ㔝ࡢ 1.6 ಸࡀᏳ඲Ỉ࡟ᑐࡋ࡚ᅛయࣇ࢓ࣥࢺ࣒ෆ࡛ࡢගᏊࡸ㟁Ꮚࡢᣲ

2࡛࠶ࡾࠊ༢⣧ィ⟬࡛ࡣ 75 × 75 cm ࡀ⌮᝿ⓗ࡞ࢧ࢖ࢬືࡀࣅ࣮࣒ࡢ࢚ࢿࣝࢠ࣮࡟ࡼࡗ࡚␗࡞ࡿࡇ࡜ࢆ♧࡛࠶ࡿࠋࡶࡋࢫ࢟ࣕࢽࣥࢢࢯࣇࢺ࢙࢘࢔ࡀᑐゅ⥺᪉ࡋࠊᅛయࣇ࢓ࣥࢺ࣒ࡢᨺᑕ⥺Ꮫⓗ≉ᛶࡀṇ☜࡟ࡣỈྥࡢࢫ࢟ࣕࣥ࡟ᑐᛂࡋ࡚࠸࡞ࡅࢀࡤࠊࢸ࣮ࣈࣝࢆᅇ

࡜␗࡞ࡿࡇ࡜ࡀᣦ᦬ࡉࢀ࡚࠸ࡿࠋ

23

医学物理 第 33 巻 第 1 号

II. ファントムの材質と使用法、検出器

Table II. Physical characteristics of commercially available water equivalent materials. NA: Nuclear Associates, NY; Radiation Product Design,
Albertsville, MN; RMI: Radiation Measurements, Inc., Middleton, WI; CIRS: Computerized Imaging Reference Systems, Inc. Norfolk, VA.
water
P en / U med

Material, manufacturer

Color

Density (kg/m3)

6 MV

10 MV

15 MV

Polystyrene, NA, RPD

Opaque

1050

1.035

1.037

1.049

1.059

Acrylic/PMMA, RPD

Clear

1185

1.031

1.033

1.040

1.044

18 MV

Solid water, RMI

Maroon

1030

1.032

1.039

1.049

1.052

Plastic water, CIRSLavender

1012

1.032

1.031

1.030

1.030

White water-RW-3, NA

White

1045

1.035

1.036

1.049

1.056

ᅛయࣇ࢓ࣥࢺ࣒ࡣ᳨ฟჾᙧ≧࡟ྜࢃࡏࡓ✸Ꮝຍࣉࢆ㑅ࡪࡇ࡜ࡀ㔜せ࡛࠶ࡾࠊࡉࡶ࡞ࡅࢀࡤㄗࡗࡓࢹᕤࡀᚲせ࡛ࠊ᳨ฟჾࢆᤄධࡋࡓ≧ែ࡛ kV ࡢ X ⥺࡛࣮ࢱࢆྲྀᚓࡍࡿྍ⬟ᛶࡀ࠶ࡿࠋSec. IV. C.࡛ヲ㏙ࡍࡿࠋ᧜ᙳࡋࠊᙧ≧ࡢ୍⮴ࢆ☜ㄆࡍ࡭ࡁ࡛࠶ࡿࠋ᳨ฟჾࡈ
࡜ࡢᙧ≧࡟ྜࢃࡏ࡚ຍᕤࡉࢀࡓࣇ࢓ࣥࢺ࣒ࢆ౑⏝II.E. ᳨ฟჾࡍࡿᚲせࡀ࠶ࡿࠋ᳨ฟჾࢆᅛయࣇ࢓ࣥࢺ࣒࡟ᤄධࡋ

II.E.1. ྛ᳨ฟჾࡢ᭷⏝ᛶᵝࠎ࡞〇㐀ᴗ⪅ࡀᖜᗈ࠸✀㢮ࡢ᳨ฟჾࢆసࡗ࡚

ࡓࡢࡕࠊ ᗘࡀᖹ⾮࡟࡞ࡿࡲ࡛⨨࠸࡚࠾ࡃᚲせࡀ࠶
30

ࡿ ࠋࣇ࢓ࣥࢺ࣒ࡢရ㉁ࡣ CT ࢆ᧜ീࡋࠊ࢔࣮ࢳࣇ

࠾ࡾࠊ㟁㞳⟽ࠊ༙ᑟయࠊࢲ࢖࢔ࣔࣥࢻ᳨ฟჾ࡞࡝ࡀ

࢓ࢡࢺࡸ CT ್ࢆ௓ࡋ࡚㟁Ꮚ⃰ᗘࡢ୙ᆒ㉁࡞㒊ศࡀᏑᅾࡍࡿࠋࡇࢀࡽࡢ᳨ฟჾࡣࢧ࢖ࢬ࡟ࡼࡗ࡚ᶆ‽ᆺࠊ࡞࠸࠿ࢆ☜ㄆࡍ࡭ࡁ࡛࠶ࡿࠋ ࡲࡓࠊࣇ࢓ࣥࢺ࣒ࡣ

࣑ࢽᆺࠊ࣐࢖ࢡࣟᆺ࡟ศ㢮࡛ࡁࡿࠋ᫂☜࡞ᐃ⩏ࡣ࡞MV ࡢ࢚ࢿࣝࢠ࣮࡟࠾࠸࡚Ỉ࡜ྠ➼ࡢᣲືࢆ♧ࡍࡼ࠸ࡀࠊ㟁㞳⟽ࡣ᭷ឤయ✚࡟ࡼࡗ࡚௨ୗࡢࡼ࠺࡟ศࡅ

࠺࡟సࡽࢀ࡚࠸ࡿࡓࡵࠊkV ࡢ CT ್ࡀỈ࡜␗࡞ࡗࡽࢀࡿࠋ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿⅬ࡟ὀពࡍࡿࠋx㞳⟽ࡣ 0.6 cm3 ࡢ᭷ឤయ✚ࢆ᭷ࡋ࡚࠸ࡿࠋ

II.D. ࣅࣝࢻ࢔ࢵࣉ࢟ࣕࢵࣉ
✵୰ฟຊಀᩘࠊࡶࡋࡃࡣ࣊ࢵࢻᩓ஘ಀᩘ㸦Sc㸧ࡢxࣇ࢓ࣥࢺ࣒ࡀ⏝࠸ࡽࢀ࡚ࡁࡓࠋၟ⏝࡛฼⏝ྍ⬟࡞ࣅ࣑ࢽᆺ㸦~10-2 cm3㸧– ࣑ࢽᆺࡢ㟁㞳⟽ࡣᖹᆒ࡜ࡋ࡚ 0.05 cm3 ࡢ᭷ឤయ✚ࢆ᭷ࡋ࡚࠸ࡿࠋ

ᐃ࡛ࡣࠊᚑ᮶ࣅࣝࢻ࢔ࢵࣉ࢟ࣕࢵࣉࡶࡋࡃࡣ࣑ࢽ
x࣐࢖ࢡࣟᆺ㸦~10-3 cm3㸧– ࣐࢖ࢡࣟᆺࡢ㟁㞳⟽ࡣᖹᆒ࡜ࡋ࡚ 0.007 cm3 ࡢ᭷ឤయ✚ࢆ᭷ࡋ࡚࠾

ࣝࢻ࢔ࢵࣉ࢟ࣕࢵࣉ㸦Radiation Products Design,
Albertville, MN 230㸧ࡣ࢚ࢿࣝࢠ࣮࡟ࡼࡗ࡚ࡣΰධ㟁Ꮚࢆ㝖ཤࡍࡿࡢ࡟༑ศ࡛࡞࠸ሙྜࡀ࠶ࡿࠋTG-74ᶆ‽ᆺ㸦~10-1 cm3㸧 – ᶆ‽ⓗ࡞ࣇ࢓࣮࣐ᙧ㟁

20ࡾࠊᐃ఩↷ᑕࡸ Gamma KnifeࠊCyberKnifeࠊIMRT
࡞࡝ᑠ↷ᑕ㔝ࡢᐃ࡟㐺ࡋ࡚࠸ࡿࠋ

࡛ࡣ஧ḟ㟁Ꮚᖹ⾮ࢆ㐩ᡂࡋࠊΰධ㟁Ꮚࢆ㝖ཤ࡛ࡁࡿ࣑ࢽࣇ࢓ࣥࢺ࣒ࡢ౑⏝ࡀ᥎ዡࡉࢀ࡚࠸ࡿࠋ4 × 4 cm2

II.E.2. ᳨ฟჾࡢ✀㢮௨ୗࡢᑠ↷ᑕ㔝࡛ࡣỈ➼౯ࡢ࣑ࢽࣇ࢓ࣥࢺ࣒ࢆ⏝II.E.2.a. 㟁㞳⟽࠸ࡿሙྜࡣ SCD = 300 cm ࡟ࡍࡿ᪉ἲࡀ౑⏝ࡉࢀ࡚㟁㞳⟽ࡣ࢚ࢿࣝࢠ࣮ࠊ⥺㔞ࠊ⥺㔞⋡࡟ᑐࡍࡿᏳᐃ

࠸ࡿࠋࡲࡓࠊTG-74 ࡛ࡣ㧗ཎᏊ␒ྕ㸦high-Z㸧ࡢᮦᛶࡸ෌⌧ᛶࡀⰋዲ࡛࠶ࡿࡇ࡜࠿ࡽࠊᨺᑕ⥺ࡢⓎぢ᫬㉁ࡢ࣑ࢽࣇ࢓ࣥࢺ࣒ࢆ⏝࠸࡚ࠊࡍ࡭࡚ࡢ Sc ࢆྠ୍ࡢࡼࡾ⌧ᅾࡲ࡛ᖜᗈࡃ౑ࢃࢀ࡚࠸ࡿࠋ㟁㞳⟽ࡣᅜᐙᶆ㊥㞳࡛⾜࠺ࡇ࡜ࡀࡼࡾࡼ࠸᪉ἲ࡜ࡋ࡚᥎ዡࡉࢀ࡚

‽࡟ᑐࡋ࡚ᰯṇࡍࡿࡇ࡜ࡀྍ⬟࡛ࠊ⥺㔞ࢆ┤᥋࠸ࡿࠋ㔠ᒓࡢ࣑ࢽࣇ࢓ࣥࢺ࣒ࢆ࢔࢖ࢯࢭࣥࢱ࡛౑⏝ࡍࡿࡇ࡜ࡀ࡛ࡁࡿࠋ㟁㞳⟽ࡣẚ㍑ⓗᏳ౯࡛ࠊᐜ᫆࡟

࡛ࡁࡿࡼ࠺ࠊTG-74 ࡛㐺ษ࡞⿵ṇಀᩘࡀ♧ࡉࢀ࡚࠸ධᡭ࡛ࡁࠊᵝࠎ࡞ᙧ≧㸦෇⟄ᙧࠊ⌫ᙧࠊᖹ⾜ᖹᯈᙧࡿ31ࠋ࣑ࢽࣇ࢓ࣥࢺ࣒ࡢ඾ᆺⓗ࡞㛗㍈᪉ྥࡢ㛗ࡉࡣ2ᐃ࡞࡝㸧࡜ࢧ࢖ࢬ㸦ᶆ‽ᆺࠊ࣑ࢽᆺࠊ࣐࢖ࢡࣟᆺ㸧ࡢ

10 g/cm ࡔࡀࠊ⿵ṇಀᩘࢆ㐺⏝ࡍࢀࡤࡇࢀ௨እࡢ㛗ࡶࡢࡀ〇㐀ࡉࢀ࡚࠸ࡿࠋHumphries ࡜ Purdy 33 ࡣᵝࠎࡉࡶ౑⏝ྍ⬟࡛࠶ࡿ 32ࠋヲ⣽ࡣ TG-74 ࡟グ㍕ࡉࢀ࡚

࡞ࣅ࣮࣒ࢹ࣮ࢱࢫ࢟ࣕࢽࣥࢢࡢࡓࡵࡢ㟁㞳⟽࡜ࡑ

࠸ࡿࠋSc ࡢࡢ≉ᛶࢆࣜࢫࢺ໬ࡋࡓࠋࡋ࠿ࡋࠊ⌧ᅾ࡛ࡣከࡃࡢ࣋

24ᐃࡣ༑ศ࡞ཌࡉࡢࣅࣝࢻ࢔ࢵࣉ࢟ࣕࢵ

II. ファントムの材質と使用法、検出器

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)ࣥࢲ࣮ࡀᨺᑕ⥺ィ࡟࠾ࡅࡿᵝࠎ࡞฼⏝ࡢࡓࡵ࡟࡞ࡽ࡞࠸ࠋከࡃࡢሙྜࡣᕤሙฟⲴ᫬࡟㐺ษ࡟ᰯṇࡉ␗࡞ࡗࡓ㟁㞳⟽ࢆ㈍኎ࡋ࡚࠸ࡿࠋ᭱᪂ࡢ◊✲ᡂᯝࡸࢀ࡚࠸ࡿࡀࠊ౑⏝๓࡟ࢳ࢙ࢵࢡࢆ⾜࠺ࡇ࡜ࡣ⢭ᗘࢆᚲせᛶ࡟ᇶ࡙࠸ࡓࠊ౑⏝┠ⓗࡈ࡜ࡢᨺᑕ⥺᳨ฟჾࡢᢸಖࡍࡿୖ࡛ᚲせ࡛࠶ࡿࠋ㟁㞳⟽࢔ࣞ࢖࡜ࢲ࢖࣮࢜

ศ㢮ࡣᵝࠎ࡞〇㐀ᴗ⪅㸦PTW, BEST, IBA, Standardࢻ࢔ࣞ࢖࡛ࢲ࢖ࢼ࣑ࢵࢡ࢙࢘ࢵࢪ࡟ᑐࡍࡿ

Imaging ࡞࡝㸧࠿ࡽᚓࡿࡇ࡜ࡀ࡛ࡁࡿࠋ

㐪࠸ࡣ࡞࠸ࡇ࡜ࡀሗ࿌ࡉࢀ࡚࠸ࡿࡢ࡛ࠊ࡝ࡕࡽࡢࢩ

ᐃ࡟ࢫࢸ࣒ࡶ౑⏝ྍ⬟࡛࠶ࡿ 44, 45ࠋ
II.E.2.b. ࢲ࢖࣮࢜ࢻ
༙ᑟయࢲ࢖࣮࢜ࢻ᳨ฟჾࡣගᏊ⥺࣭㟁Ꮚ⥺࠸ࡎࢀ࡟࠾࠸࡚ࡶࣅ࣮࣒ࢹ࣮ࢱ

II.E.2.d. ࢲ࢖࢔ࣔࣥࢻ᳨ฟჾ
ࢲ࢖࢔ࣔࣥࢻ᳨ฟჾࡣ㟁Ꮚ-ṇᏍᑐࡢྍືᛶ࡟ඃ

ᐃ࡟ᗈࡃ⏝࠸ࡽࢀ࡚࠸

ࡿࠋࢲ࢖࣮࢜ࢻࡢ≉ᚩࡣ㏿࠸ᛂ⟅᫬㛫㸦㟁㞳⟽࡛ࡣࢀࡓᅛయ᳨ฟჾ࡛ࠊ㟁㞳ᨺᑕ⥺ࡢ

msec ࡛࠶ࡿࡢ࡟ᑐࡋPsec ࣮࢜ࢲ࣮㸧࡜ඃࢀࡓ✵㛫ⓗ࡞༙ᑟయ᳨ฟჾ࡛࠶ࡿࠋࢲ࢖࢔ࣔࣥࢻ᳨ฟჾࡢ

ศゎ⬟ࢆᣢࡘࡇ࡜ࠊ㟁ᅽࢆ༳ຍࡍࡿᚲせࡀ࡞࠸ࡇ࡜ࠊ

㸦㧗ឤᗘ࡛࠶ࡿࡇ࡜ࡀᣲࡆࡽࢀࡿࠋຍ࠼࡚ࠊࢲ࢖࣮࢜

㟁㞳ᨺᑕ⥺ࡀ྾཰ࡉࢀࡿ࡜≀㉁ࡢఏᑟᛶࡀ୍᫬ⓗࢻࡣ⮫ᗋ౑⏝ࡉࢀ࠺ࡿ 4-20 MeV ࡢ㟁Ꮚ⥺࡟࠾࠸࡚ࠊ

࡟ኚ໬ࡍࡿ 46-50ࠋࢲ࢖࢔ࣔࣥࢻ᳨ฟჾࡢᛂ⟅ࡣ྾཰ࢩࣜࢥࣥ࡜Ỉࡢ㛫࡟࠾ࡅࡿ㉁㔞⾪✺㜼Ṇ⬟ẚࡀ࢚⥺㔞⋡࡟ṇẚ౛ࡋࠊ᪉ྥ౫Ꮡᛶࡣ♧ࡉࡎࠊ⤌ᡂࡣே

34-36

య࡟㏆࠸ࠋ᭷ឤయ✚ࡣ 1.0-6.0 mm3 ࡜㠀ᖖ࡟ᑠࡉࡃࠊ

ࢿࣝࢠ࣮࡟౫Ꮡࡋ࡞࠸
ࡣ≉࡟㟁Ꮚ⥺ࡢࠋࡑࢀࡺ࠼ࠊࢲ࢖࣮࢜ࢻ

ᐃ࡟࠾࠸࡚᭷ຠ࡞᳨ฟჾ࡜࡞ࡿࠋ

ᐃ࡟ᑐࡋ࡚㨩ຊᐃ㸧⌮ㄽࡣࢲ࢖࣮࢜ࢻ᳨ฟჾ࡜㠀ᖖ࡟ఝ࡚࠾ࡾࠊ

ᑠ↷ᑕ㔝ࡢ࣏࢖ࣥࢺ⥺㔞ᐃ࡜ࣉࣟࣇ࢓࢖ࣝ

ᐃ≉ᐃࡢࢲ࢖࣮࢜ࢻࡣ≉ᐃࡢᨺᑕ⥺࡟ࡢࡳ౑⏝ࡍ࡭࡟㐺ࡋ࡚࠸ࡿࠋࢲ࢖࢔ࣔࣥࢻ᳨ฟჾࡣࢃࡎ࠿࡟⥺㔞ࡁ࡛࠶ࡾࠊ㟁Ꮚ⥺⏝ࡣ㟁Ꮚ⥺ࡢࠊගᏊ⥺⏝ࡣගᏊ⥺⋡౫Ꮡࢆ♧ࡍࡀࠊỈ୰࡟࠾ࡅࡿࢫ࢟ࣕࢽࣥࢢ

ࡢ౑⏝ࡍࡿࡇ࡜ࡀ࡛ࡁࡿࠋࢲ࢖࢔ࣔࣥࢻ᳨ฟჾࡣ〇㐀ᐃ࡟ࡢࡳ౑⏝࡛ࡁࡿࡇ࡜࡟ὀពࡍࡿᚲせࡀ࠶ࡿࠋࡲࡓࠊࢲ࢖࣮࢜ࢻ᳨ฟჾࡣ

ᗘࠊ⥺㔞⋡㸦SSDࡢ㐪࠸ࡸ࢙࢘ࢵࢪ౑⏝᫬࡞࡝㸧ࠊ࢚ࢿࣝࢠ࣮

34, 36-38ᐃ࡟ࡀ㞴ࡋ࠸ࡓࡵࠊ࡯࠿ࡢᅛయ᳨ฟჾ࡟ẚ࡭࡚㧗౯࡛࠶ࡿࠋ࡟ᑐࡋ࡚౫Ꮡᛶࡀ࠶ࡾࠊࡲࡓゅᗘ౫Ꮡᛶࡀ࠶ࡿࡶࡢ
ࡶᏑᅾࡍࡿࠋTG-62 39 ࡛᥎ዡࡉࢀ࡚࠸ࡿ⢭ᗘࢆ㐩ᡂࡍࡿࡓࡵ࡟ࡣࠊࡇࢀࡽࡢ౫Ꮡᛶࢆ⿵ṇࡍࡿ࠿ࠊ⥺㔞

II.E.2.e. ⇕⺯ග⥺㔞ィ⇕⺯ග⥺㔞ィ 51㸦TLD㸧ࡣ࣏࢖ࣥࢺ⥺㔞ࡢᐃࡸ⋡ࡸ࢚ࢿࣝࢠ࣮࡬ࡢ౫Ꮡᛶࡀ᭱ࡶᑠࡉ࡞ࢲ࢖࣮࢜

in-vivo ࢻࢩ࣓ࢺࣜ࡟౑⏝ࡉࢀ࡚ࡁࡓࠋTLD ࡢᙧ≧ࡣࢻࢆ౑⏝ࡍ࡭ࡁ࡛࠶ࡿࠋࣅ࣮࣒ࢹ࣮ࢱྲྀᚓ࡟࠾ࡅࡿ

ࣟࢵࢻᙧࠊࢳࢵࣉᙧࠊࣃ࢘ࢲ࣮≧࡞࡝ᵝࠎ࡛࠶ࡿࠋ

ࢲ࢖࣮࢜ࢻ᳨ฟჾࡢ౑⏝࡟㛵ࡋ࡚ࡣ▩┪ࡍࡿᩥ⊩ࣟࢵࢻᙧ࡜ࢳࢵࣉᙧࡣࠊ㐺ษ࡟⇕ฎ⌮㸦࢔ࢽ࣮ࣜࣥ

40-43ࡀᏑᅾࡍࡿࡢ࡛ࠊࢲ࢖࣮࢜ࢻ᳨ฟჾࢆ౑⏝ࡍࡿࢢ㸧ࡍࡿࡇ࡜࡛෌౑⏝ࡍࡿࡇ࡜ࡀ࡛ࡁࡿࠋTLD ࡣᙉ๓࡟ࠊྛ᪋タ࡛㟁㞳⟽࡜ẚ㍑ࡋ࡚ṇᖖ࡞ືస࡜ࢹ࣮

࠸࢚ࢿࣝࢠ࣮౫Ꮡᛶࡸࣇ࢙࣮ࢹ࢕ࣥࢢ⌧㇟ࠊ㠀⥺ᙧࢱࡢṇ☜ᛶࢆ☜ㄆࡍ࡭ࡁ࡛࠶ࡿࠋ

࡞⥺㔞ฟຊࢆᣢࡘࠋࡋ࠿ࡋ࡞ࡀࡽࠊࡇࢀࡽࡢຠᯝࡣ
MV ࣅ࣮࣒࡟ᑐࡋ࡚ࡣẚ㍑ⓗᑠࡉ࠸ 52, 53ࠋ⢭ᗘࡣ↷

II.E.2.c. 㓄ิᆺ᳨ฟჾ

ᑕἲ࡜ᐃἲ࡟౫Ꮡࡋࠊs5%௨ୗࡢ⢭ᗘࢆ㐩ᡂࡍࡿ㓄ิᆺ᳨ฟჾࡣ࣮࢜ࣉࣥࣅ࣮࣒࡟ᑐࡋ࡚ྠ᫬

ࡇ࡜ࡀ࡛ࡁ 54ࠊRadiological Physics Center ࡜ᐃࡀྍ⬟࡛࠶ࡿࡢ࡛ࠊ≉࡟ࢯࣇࢺ࢙࢘ࢵࢪ㸦ࢲ࢖ࢼ

calibration laboratories ࡛ࡣs1%௨ୗࡢ⢭ᗘ࡛ࡢ࣑ࢵࢡ࢙࢘ࢵࢪࡸࣂ࣮ࢳ࢙ࣕࣝ࢘ࢵࢪ㸧ࡢࣉࣟࣇ࢓

ࢆ㐩ᡂࡋ࡚࠸ࡿࠋTLD ࡣࢥ࣑ࢵࢩࣙࢽࣥࢢࢹ࣮ࢱࡢ

࢖ࣝᐃ࡟㐺ࡋ࡚࠸ࡿࠋ〇㐀ᴗ⪅࡟ࡼࡗ᳨࡚ฟࢩࢫ

ࢸ࣒ࡣ㸦✵Ẽ࠶ࡿ࠸ࡣᾮయ࡛‶ࡓࡉࢀࡓ㸧㟁㞳⟽࢔ᐃᐃ࡟ࡣ୙ྥࡁ࡛࠶ࡿࡀࠊᑠ↷ᑕ㔝ࡸ IMRT ࡢ࣏࢖ࣥࢺ⥺㔞ࡢ᳨ド࡟⏝࠸ࡿࡇ࡜ࡀ࡛ࡁࡿࠋ

ࣞ࢖࠿ࢲ࢖࣮࢜ࢻ࢔ࣞ࢖࡜࡞ࡗ࡚࠸ࡿࠋ」ᩘࡢ᳨ฟ
ჾࡀ┤⥺ⓗ࡟㓄⨨ࡉࢀ࡚࠸ࡿࡓࡵࠊࢹ࣮ࢱ

ᐃࢆ⾜

II.E.2.f. ࣇ࢕࣒ࣝ࠺๓࡟ࠊྛ᳨ฟჾࡢቑᖜ⋡ࢆỴᐃࡍࡿࡓࡵ〇㐀ᴗ⪅ࣇ࢕࣒ࣝࡣගᏛ⃰ᗘࡢኚ໬࡟ᇶ࡙ࡃ⥺㔞ࡢᐃࡵࡓ↷ᑕ㔝ࢧ࢖ࢬ࡛ឤᗘᰯṇࢆ⾜ࢃ࡞ࡅࢀࡤ

21⏝࠸ࡽࢀࡿࠋ TG-69ᐃ࡟࡟♧ࡉࢀ࡚࠸ࡿࡼ࠺࡟ࠊ୍⯡25

医学物理 第 33 巻 第 1 号

II. ファントムの材質と使用法、検出器ⓗ࡟ࣇ࢕࣒ࣝࡣ↷ᑕ㔝ࢧ࢖ࢬࠊ῝ࡉࠊࣅ࣮࣒࢚ࢿࣝ

ჾࡀࡼࡃ㐺ࡋ࡚࠸ࡿࠋ㟁㞳⟽ࡣࡑࡢ᭷ຠᛶࠊ౯᱁ࠊ

ࢠ࣮ࠊ⌧ീᶵࡢ≧ែࡸࡑࡢ௚ࡢせᅉ࡟ᙳ㡪ࢆཷࡅࡿࠋ

⢭ᗘࠊ౑࠸ࡸࡍࡉ࠿ࡽ᭱ࡶ୍⯡ⓗ࡟౑⏝ࡉࢀࡿࠋ᳨

ࣇ࢕࣒ࣝ࡟ࡣࠊࣁࣟࢤࣥ໬㖟ࢆྵࡴࡶࡢ࡜ࠊ࢞ࣇࢡ

ฟჾࡣ࣑ࣟࢵࢡࣇ࢕࣒ࣝࡢ 2 ✀㢮ࡀᏑᅾࡍࡿࠋTG-69 ࡜ࢧ࢖ࢬࠊศゎ⬟ࠊࢹ࣮ࢱ཰㞟࡟ᚲせ࡞᫬㛫࡞࡝ࡢほ

TG-55

55

ᐃࢹ࣮ࢱࢆ࡝ࡢࡼ࠺࡟౑⏝ࡍࡿ࠿ࠊ↷ᑕ㔝࡛ࡣࠊࡑࢀࡒࢀࣁࣟࢤࣥ໬㖟ࣇ࢕࣒ࣝ࡜࢞

Ⅼ࠿ࡽៅ㔜࡟㑅ᢥࡍࡿᚲせࡀ࠶ࡿࠋ౛࠼ࡤࠊ୍⯡ⓗࣇࢡ࣑ࣟࢵࢡࣇ࢕࣒ࣝ࡟ᑐࡋ࡚ᴫㄝࡉࢀ࡚࠸ࡿࠋࣁ

࡞ෆᚄ 4-6 mm ࡢ㟁㞳⟽ࡣ 4 × 4 cm2 ௨ୖࡢ↷ᑕ㔝ࢧࣟࢤࣥ໬㖟ࣇ࢕࣒ࣝࡣගᏊ⥺࡟ᑐࡋ࡚ᙉ࠸࢚ࢿࣝ

࢖ࢬࡢࢠ࣮౫Ꮡᛶࢆ♧ࡍࡀࠊMeV 㡿ᇦࡢ㟁Ꮚ⥺࡛ࡣẚ㍑ⓗࢀࡿᑠ↷ᑕ㔝࡟࠾ࡅࡿᙳ㡪ࡀᑡ࡞࠸ࠋࡇࡢ⌮⏤࠿ࡽࣇ࢕࣒ࣝࡣ㟁Ꮚ⥺࡟ᑐᇦ࡟ࡰࡅࡀⓎ⏕ࡋṇ☜࡟ࡋ࡚౑⏝ࡍࡿࡇ࡜ࡀ࡛ࡁࡿ

22, 56

ࠋࣇ࢕࣒ࣝ࡟ࡼࡗ࡚

ᐃ࡟᭷ຠ࡛࠶ࡿࡀࠊ IMRT ࡞࡝࡟ᚲせ࡜ࡉ2

4 × 4 cm ௨ୗࡢᐃ࡟ࡣ㐺ᙜ࡛࡞ࡃࠊ༙ᙳ㡿ᐃࡍࡿࡇ࡜ࡣ࡛ࡁ࡞࠸ࠋ

ᐃ࡟ࡣࠊከࡃࡢሙྜ࠶ࡿ⛬ᗘᑠࡉྲྀᚓࡉࢀࡓࣅ࣮࣒ࢹ࣮ࢱࡣ㟁㞳⟽࡟ࡼࡿࡶࡢ࡟ẚ࡞య✚ࡢ㟁㞳⟽࠿ࢲ࢖࣮࢜ࢻࡀ⏝࠸ࡽࢀࡿ 64-68ࠋᑠ࡭࡚⢭ᗘࡀప࠸࠿ࡶࡋࢀ࡞࠸ࡀࠊᑠ↷ᑕ㔝ࡸࢯࣇࢺࡉ࡞య✚ࡢ㟁㞳⟽ࡸࢲ࢖࣮࢜ࢻࡣᑠ↷ᑕ㔝࡜ẚ㍑

࢙࢘ࢵࢪࡢ 2 ḟඖ⥺㔞ศᕸࢆྲྀᚓࡍࡿࡇ࡜ࡀ࡛ࡁࡿࠋ

ࡋ࡚኱↷ᑕ㔝࡟ᑐࡋ࡚␗࡞ࡿ≉ᛶࢆ♧ࡍࡓࡵࠊࡍ࡭

Yin ࡢሗ࿌ࡢࡼ࠺࡟ࠊᑠ↷ᑕ㔝࡟ᑐࡋ࡚ࣇ࢕࣒ࣝࢆ

࡚ࡢ↷ᑕ㔝ࢧ࢖ࢬ࡛⏝࠸ࡿࡇ࡜ࡣ࡛ࡁ࡞࠸ࠋᑠ↷ᑕ⏝࠸ࡿሙྜࠊࣇ࢕࣒ࣝࢫ࢟ࣕࢼ࡟ࡼࡿࡰࡅࢆ⪃៖ࡍ㔝ࡢࣉࣟࣇ࢓࢖ࣝࡣ SFD㸦Stereotactic field diodes㸧

60

ࡿᚲせࡀ࠶ࡿ ࠋࡸࣆ࣏ࣥ࢖ࣥࢺࢳ࢙ࣥࣂ࣮ࡢࡼ࠺࡞࣐࢖ࢡࣟᆺ᳨
ฟჾ࡛

II.E.2.g. MOSFET ᳨ฟჾࢼࣝࡀẚ㍑ⓗᑠࡉ࠸ࡓࡵࠊSec.III.A.3.g ࡛㆟ㄽࡉࢀ

MOSFET ᳨ฟჾࡣ⮫ᗋ࡟࠾ࡅࡿ
ド

62

ᐃࡍࡿᚲせࡀ࠶ࡿࠋࡇࢀࡽࡢ᳨ฟჾࡣࢩࢢ

61

ᐃ ࡜ IMRT ᳨ࡢ౑⏝࡟࠾࠸࡚Ⓨᒎࡋ࡚ࡁࡓࠋᚤᑠࢧ࢖ࢬ࡛࠶

ࡿࡇ࡜࠿ࡽࠊMOSFET ࡣᑠ↷ᑕ㔝ࡢࡿࡼ࠺࡟ࢫ࢟ࣕࢽࣥࢢ㸦ࢧࣥࣉࣜࣥࢢ㸧᫬㛫ࢆቑࡸࡋ࡚ SN ẚࢆᨵၿࡍࡿᚲせࡀ࠶ࡿࠋᐃࠊᑠ⥺※἞

⒪ࠊin-vivo ࢻࢩ࣓ࢺࣜ࡟㐺ࡋ࡚࠸ࡿࠋMOSFET ࡢ෌⌧ᛶࠊ┤⥺ᛶࠊ࢚ࢿࣝࢠ࣮࣭ゅᗘ౫Ꮡᛶ࡞࡝ࡣᚑ᮶
61ࡢ᳨ฟჾ࡜ྠ➼࡛࠶ࡿ ࠋMOSFET ࡣᑑ࿨㸦

II.E.4. ᳨ฟჾࡢᛂ⟅࡜⿵ṇ᭷㝈ࡢయ✚ࢆࡶࡘ᳨ฟჾࡣࣉࣟࣇ࢓࢖ࣝࡢᗈࡀ

ᐃྍࡾ࡟ᑐࡋ࡚᭷ឤయ✚࡛ᖹᆒࡉࢀࡓᛂ⟅ࢆ♧ࡍࠋࡶࡋ⬟࡞⥲⥺㔞㸧ࡀ▷࠸ࡓࡵࠊࣅ࣮࣒ࢹ࣮ࢱࢥ࣑ࢵࢩࣙ

ᑠయ✚ࡢ᳨ฟჾࡀ౑࠼࡞࠸࡞ࡽࡤࠊࢹࢥ࣮ࣥ࣎ࣜࣗ

ࢽࣥࢢ࡟ࡣྥ࠿ࡎࠊ≉ᐃࡢ࣏࢖ࣥࢺ⥺㔞ࢩࣙࣥἲ㸦㏫␚ࡳ㎸ࡳ✚ศ㸧ࡀ౑⏝࡛ࡁࡿ 69-76ࠋᐃ࡟౑⏝ᐃࡉࢀࡓࣉࣟࣇ࢓࢖ࣝࡢ᳨ฟჾࢧ࢖ࢬ࡟ࡼࡿ༙ᙳ

ࡉࢀࡿࠋ㡿ᇦࡢᗈࡀࡾࡣ detector convolution kernel ࡟ࡼࡗ࡚ㄝ࡛᫂ࡁ70-76ࠊ ┿ࡢ༙ᙳ㡿ᇦࢆ detector convolution

II.E.2.h. Bang gel ᳨ฟჾ
Bang gel ᳨ฟჾ 63 ࡣ⤌ᡂࡀேయ࡟㏆ࡃࠊ3 ḟඖ⥺㔞ศᕸࢆ㧗ศゎ⬟࡛ᐃ࡛ࡁࡿࠋᖜᗈ࠸࢚ࢿࣝࢠ࣮

kernel ࢆ⏝࠸࡚እᤄࡍࡿࡇ࡜ࡀྍ⬟࡛࠶ࡿࠋࢹࢥࣥ
࣮࣎ࣜࣗࢩࣙࣥἲࡣࣀ࢖ࢬࡢᙳ㡪ࢆཷࡅࡸࡍࡃࠊࣀ

ᐃࡍࡿ࢖ࢬࢆ㝖ཤࡍࡿᚲせࡀ࠶ࡿ 72ࠋࡇࡢၥ㢟ࡣ༙ᙳ࡜ࡢ࡟⌮᝿ⓗ࡛࠶ࡿࠋ⥺㔞ศᕸࡢ࢖࣓࣮ࢪࢆసᡂࡍࡿ

detector convolution kernel ࡢ୧᪉ࡀゎᯒⓗ㛵ᩘ࡛グࡢ࡟ MRI ࡸ CTࠊoptical CT ࡀᚲせ࡜࡞ࡾࠊࡇࢀࡽ

㏙࡛ࡁࢀࡤゎỴ࡛ࡁࡿࠋ༙ᙳ࡜ detector convolutionࡢ᧜ീᢏ⾡ࡣ࢔࣮ࢳࣇ࢓ࢡࢺࡢᙳ㡪ࢆཷࡅࡸࡍ࠸ࠋ

kernel ࡢゎᯒⓗ㛵ᩘ࡟ࡣ࠸ࡃࡘ࠿ࡢ◊✲ࡀ࠶ࡿࡀ୍⯡ⓗ࡟ࠊࢤࣝࢆ⏝࠸ࡓ

77,78࡟ᑐࡋ࡚౫Ꮡᛶࡣ࡞ࡃࠊ3 ḟඖ⥺㔞ศᕸࢆᐃ࡛ࡣከࡃࡢᡭ㡰ࢆᚲせࠊࡇࡢࡼ࠺࡞෕㛗࡞ࣉࣟࢭࢫࢆ㑊ࡅࡿࡓࡵ࡟ࡶ࡜ࡋࠊSRS ࡸ IMRT ࢆ㝖࠸࡚ࣅ࣮࣒ࢹ࣮ࢱࢥ࣑ࢵࢩ

ᑠ↷ᑕ㔝ࡢࣙࢽࣥࢢ࡟ࡣ㐺ࡉ࡞࠸ࠋ࡯࠺ࡀࡼ࠸ࠋࢹࢥ࣮ࣥ࣎ࣜࣗࢩࣙࣥἲࡣ」㞧࡛ࠊከᐃ࡟ࡣ࣐࢖ࢡࣟࢳ࢙ࣥࣂ࣮ࢆ⏝࠸ࡓᩘࡢࣉࣟࣇ࢓࢖ࣝ࡟ᑐࡋ࡚⏝࠸ࡿ࡟ࡣ᫬㛫ࡀ࠿࠿
II.E.3. ᳨ฟჾࡢ㑅ᢥࢫ࢟ࣕࢽࣥࢢỈࣇ࢓ࣥࢺ࣒ࢆ⏝࠸ࡓࣅ࣮࣒ࢹ࣮
ࢱ

26

ᐃ࡟ࡣ㟁㞳⟽ࠊࢲ࢖࣮࢜ࢻࠊࢲ࢖࢔ࣔࣥࢻ᳨ฟ

ࡿࡓࡵࠊၟ⏝ࢯࣇࢺ࢙࢘࢔ࡀ฼⏝ྍ⬟࡛࡞࠸㝈ࡾࠊ㝈ᐃࡋࡓࢹ࣮ࢱࢭࢵࢺ࡟ᑐࡍࡿ᭱⤊ⓗ࡞㑅ᢥ⫥࡜ࡋ࡚฼⏝ࡍ࡭ࡁ࡛࠶ࡿࠋ

III. スキャニングシステムのセットアップ

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)࡛ࡁ࡞࠸ࠋ
III. ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢࢭࢵࢺ࢔ࢵࣉ

 ᵝࠎ࡞⏝㏵࡟ᛂࡌࡓᑓ⏝ࡢ᳨ฟჾࡀቑ࠼࡚ࡁࡓ

㐺ษ࡟Ỉࣇ࢓ࣥࢺ࣒ࢩࢫࢸ࣒ࢆࢭࢵࢺ࢔ࢵࣉࡍ

ࡓࡵࠊ࣮ࣘࢨ࣮ࡣ᪂ࡋ࠸࢔ࢡࢭࢧࣜ㸦᳨ฟჾࠊࢣ࣮

ࡿࡇ࡜ࡣ࣮࣡ࢡࣇ࣮ࣟࡢᨵၿ࡟ࡘ࡞ࡀࡿࡀࠊࡼࡾ㔜ࣈࣝࠊࢥࢿࢡࢱࠊ࢔ࢲࣉࢱ㸧࡜᪤Ꮡࡢࢫ࢟ࣕࢽࣥࢢ

せ࡞ࡇ࡜ࡣࠊ኱㔞ࡢࢹ࣮ࢱฎ⌮ࡸ෌ࢩࢫࢸ࣒ࢆ᥋⥆ࡍࡿᚲせࡀ࠶ࡿࠋࡑࡢ⤖ᯝࠊᵝࠎ࡞ᐃ࡞࡝࡟ࡘ࡞

ࡀࡿ᭱㐺࡛࡞࠸ࢹ࣮ࢱࢆᚓࡿྍ⬟ᛶࢆῶࡽࡍࡇ࡜

ჾලࢆ⤌ࡳྜࢃࡏ࡚౑⏝ࡍࡿࡇ࡜࡟࡞ࡾࠊ࣮ࣘࢨ࣮

࡛࠶ࡿࠋࣇ࢓ࣥࢺ࣒ࡢタ⨨ࡸࢹ࣮ࢱ཰㞟ࡢィ⏬ࢆ❧ࡣࡑࢀࡽ⤫ྜࢩࢫࢸ࣒ࡢᛶ⬟ࢆ☜ㄆࡋ࡞ࡅࢀࡤ࡞

࡚ࡿ๓࡟ࠊࡲࡎࡣ⌧ᅾࡢࢣ࣮ࣈࣝ㓄⥺ࢆ☜ㄆࡍࡿᚲࡽ࡞࠸ࠋ୍⯡ⓗ࡟ࡣࠊࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡈ࡜࡟

せࡀ࠶ࡿࠋࡶࡋࠊ⌧ᅾ౑⏝ࡉࢀ࡚࠸ࡿࢣ࣮ࣈࣝࡀࢫ

㐺ษ࡞᳨ฟჾࡢ࢔ࢱࢵࢳ࣓ࣥࢺࡀᚲせ࡜࡞ࡿࠋ࢟ࣕࣥ࡟฼⏝࡛ࡁ࡞ࡅࢀࡤࠊ᪂ࡓ࡟ࢣ࣮ࣈࣝࢆ㓄⥺ࡍࡿᚲせࡀ࠶ࡿࠋࡲࡓࠊ἞⒪⿦⨨ࡢࢥࣥࢯ࣮ࣝ࡜ࣇ

III.A.1. ࢫ࢟ࣕࢽࣥࢢ㸦ࣇ࢕࣮ࣝࢻ㸧⥺㔞ィ࡜ࣜࣇ࢓ࣥࢺ࣒ไᚚ⏝ࡢ PC ࢆ୪࡭࡚౑⏝ࡍࡿࡇ࡜࡛୙せ࢓ࣞࣥࢫ⥺㔞ィ࡞ືసࡀῶࡿࡓࡵࠊࢹ࣮ࢱࡢ཰㞟᫬㛫ࢆ▷ࡃࡍࡿࡇ୍⯡ⓗ࡟ࡣࠊࢫ࢟ࣕࢽࣥࢢࢱࣥࢡෆࢆࣉࣟࢢ࣒ࣛ
ࡢ࡜࠾ࡾ࡟⛣ືࡋ࡚࡜ࡀ࡛ࡁࡿࠋ

ᐃࢆ⾜࠺ࣇ࢕࣮ࣝࢻ⥺㔞ィ㸦ࡶࡋࡃࡣࢫ࢟ࣕࢽࣥࢢ⥺㔞ィ㸧࡜ࠊ↷ᑕ㔝ෆ࡟ᅛ
III.A. ࢫ࢟ࣕࢼࡢ᳨ド࡜☜ㄆᐃࡋ࡚ ㏆ᖺ౑⏝ࡉࢀ࡚࠸ࡿ 3D ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣ

ࣇ࢓ࣞࣥࢫ⥺㔞ィࡢ஧ࡘࡢ⥺㔞ィࡀࢫ࢟ࣕࢽࣥࢢ

㠀ᖖ࡟㧗⢭ᗘ࡛ṇ☜࡛࠶ࡿࠋࡋ࠿ࡋ࡞ࡀࡽ
Mellenberg ࡽ7933

ࡸࠊHumphries ࡜ Purdy

ᐃࢆ⾜࠺㸦ฟຊࡢࡤࡽࡘࡁࢆ⿵ṇࡍࡿ㸧ࣜᐃ࡟ᚲせ࡜࡞ࡿࠋࣜࣇ࢓ࣞࣥࢫ⥺㔞ィࢆ⏝࠸ࡿࡇࡀᥦ᱌ࡋ࡜࡛ฟຊࡢ▐㛫ⓗ࡞ኚືࡸࢻࣜࣇࢺࢆ㝖ཤࡍࡿࡇࡓࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢᇶᮏⓗ࡞ QA ࡣ⾜࠺࡭ࡁ࡜ࡀ࡛ࡁࡿࡓࡵࠊࡍ࡭࡚ࡢ

࡛࠶ࡿࠋᐃᮇⓗ࠿ࠊᑡ࡞ࡃ࡜ࡶỈࣇ࢓ࣥࢺ࣒ࡢ౑⏝࡜ࢆᙉࡃ᥎ዡࡍࡿࠋ

ᐃ࡟࠾࠸࡚౑⏝ࡍࡿࡇ๓࡟ࡣ࢔࣮࣒ࡀ xࠊyࠊzࠊᑐゅ⥺᪉ྥ࡟⮬⏤࡟ືࡃࣇ࢕࣮ࣝࢻ⥺㔞ィ࡜ࣜࣇ࢓ࣞࣥࢫ⥺㔞ィࡣࠊࢫ࢟ࡇ࡜ࢆ☜ㄆࡍࡿࡇ࡜࡛ရ㉁ࢆಖドࡍࡿࡇ࡜ࡀ࡛ࡁ

ࣕࣥࡢṇ☜ࡉ࡜෌⌧ᛶࢆಖࡘࡓࡵ࡟ࠊ≉ὀࡶࡋࡃࡣ

ࡿ࡛࠶ࢁ࠺ࠋࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢ〇㐀ᴗ⪅ࡣᖺᑓ⏝ࡢಖᣢල࡛ᚲࡎᅛᐃࡋ࡞ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋᩓ஘

࡟୍ᅇ⾜ࢃࢀࡿ࡭ࡁண㜵ⓗ࣓ࣥࢸࢼࣥࢫࢧ࣮ࣅࢫ⥺ࡀ ᐃࢹ࣮ࢱࡢ⢭ᗘにᙳ㡪ࢆཬࡰࡍࡢ࡛ࠊ㔠ᒓ〇ࡢࢆᥦ౪ࡋ࡚࠸ࡿࠋࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢṇ☜ࡉ࡜ಖᣢලࡣ㑊ࡅࡿ࡭ࡁ࡛࠶ࡿࠋ౑⏝ࡍࡿ⥺㔞ィ࡜ࢫ࢟┤⥺ᛶࡣ㛗࠸㊥㞳ࢆ㉮ᰝࡋ࡚ࢳ࢙ࢵࢡࡍ࡭ࡁ࡛࠶

ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢ〇㐀ᴗ⪅ࡀ␗࡞ࡿሙྜࡣࠊ᪂ࡋ

ࡿࠋࢥ࣑ࢵࢩࣙࢽࣥࢢ⏝ࡢࣅ࣮࣒ࢹ࣮ࢱࢆ

࠸⥺㔞ィࡢ〇㐀ᴗ⪅ࡀసᡂࡋࡓ㐺ษ࡞࢔ࢲࣉࢱࢆ

ᐃࡍࡿ๓࡟ࡣࠊ᥋⥆ࢣ࣮ࣈࣝࡢ₃㟁ࡸ෌⌧ᛶ࡜ྠᵝ࡟ࠊࢫ౑⏝ࡍ࡭ࡁ࡛࠶ࡿࠋỈ୰ࡢ⥺㔞ࢆ࢟ࣕࢽࣥࢢࢱࣥࢡࡢ≀⌮ⓗ࡞≧ែ㸦Ỉࡢ₃ࢀࡸࠊࡦ㔞ィࢆࢸ࣮ࣉࡸῧ࠼ᮌ࡛ᅛᐃࡍࡿ࡜ࠊᅛᐃࡀ⦆ࡃ࡞

33

ᐃࡍࡿ㝿࡟ࠊ⥺ࡧ㸧ࡸᶵᲔⓗ࡞Ᏻᐃᛶࢆ☜ㄆࡍࡿ࡭ࡁ࡛࠶ࡿ ࠋࡗ࡚ࡋࡲ࠺ࡓࡵࠊ෌⌧ᛶࡢప࠸ࢹ࣮ࢱࢆ཰㞟ࡋ࡚ࡋ ࡍ࡭࡚ࡢ㒊ရࡀྠࡌ〇㐀ᴗ⪅࡟ࡼࡗ࡚సࡽࢀ࡚

ࡲ࠺ࡇ࡜࡟࡞ࡾࠊࢥ࣑ࢵࢩࣙࢽࣥࢢࡢ᫬㛫ࡀቑຍࡍ࠸ࡿࢩࢫࢸ࣒ࡢሙྜࠊ୍⯡ⓗ࡟ࡣⰋዲ࡞ࢹ࣮ࢱࡀ཰

ࡿࡓࡵ⾜ࡗ࡚ࡣ࡞ࡽ࡞࠸ࠋ

㞟࡛ࡁࡿ⤌ࡳྜࢃࡏࡔ࡜⪃࠼ࡽࢀࡿࡀࠊ࣮ࣘࢨ࣮ࡣ

ࣜࣇ࢓ࣞࣥࢫ⥺㔞ィࡣࣇ࢕࣮ࣝࢻ⥺㔞ィࡢࢫ࢟౑⏝๓࡟୙ලྜࡸ㏻ಙ࢚࣮ࣛࡢ᭷↓ࢆ☜ㄆࡍࡿ࡭ࣕࣥ⠊ᅖୖ࡟ࡣタ⨨ࡋ࡚ࡣ࡞ࡽ࡞࠸ࠋࣜࣇ࢓ࣞࣥࢫ

ࡁ࡛࠶ࡿࠋࡉࡽ࡟ࠊỈᵴ࡜ྠࡌ〇㐀ᴗ⪅ࡀ㈍኎ࡋ࡚

⥺㔞ィࡀࣇ࢕࣮ࣝࢻ⥺㔞ィࡢࢫ࢟ࣕࣥ⠊ᅖୖ࡟ࡁ࠸ࡿ㒊ရ㸦≉࡟᳨ฟჾ㸧࡟࠾࠸࡚ࡶࠊࡑࢀࡒࢀ࡟஫

࡚ࡋࡲ࠺ࡼ࠺࡞ᑠࡉ࡞↷ᑕ㔝ࡢሙྜ࡟ࡣࠊࣜࣇ࢓ࣞ

80᥮ᛶࡀ࡞࠸ሙྜࡶ࠶ࡿࠋSchmid ࡜ Morris ࡀ㛤Ⓨࣥࢫ⥺㔞ィࢆ౑⏝ࡍࡿ௦ࢃࡾ࡟ࠊࢫ࢟ࣕࣥ᫬㛫ࢆ㛗ࡋࡓࡼ࠺࡞ࠊࢫ࢟ࣕࢼ࡜἞⒪⿦⨨ࢆྠᮇࡉࡏࡿࡇ࡜

ࡃࡋ࡚ࢹ࣮ࢱ㔞ࢆቑࡸࡍ᪉ἲࡀ⏝࠸ࡽࢀࡿࠋ

࡟ࡼࡾ↷ᑕ㔝࡞࡝ࢆ⮬ື࡟ኚ໬ࡉࡏࡿࢩࢫࢸ࣒ࡣ

ࣜࣇ࢓ࣞࣥࢫ⥺㔞ィ࡜ࣇ࢕࣮ࣝࢻ⥺㔞ィࡢ✀㢮ṇ☜࡟ືసࡍࡿ࠿ࢆヨ㦂ࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋࡇࡢ

ࡣ๓㏙㸦II.E.3.㸧ࡢࡼ࠺࡟ࠊ

ࡼ࠺࡞ᮍ᮶ⓗ࡞ࢩࢫࢸ࣒ࡣၟ⏝⿦⨨࡛ࡣࡲࡔ฼⏝ࡢ⏝㏵࡟ᛂࡌ࡚㑅ࡪ࡭ࡁ࡛࠶ࡿࠋࡲࡓࠊ஧ࡘࡢ⥺㔞ᐃࡍࡿࣅ࣮࣒ࢹ࣮ࢱ

27

医学物理 第 33 巻 第 1 号

III. スキャニングシステムのセットアップ

FIG. 2. Comparison of depth doses with good and bad chambers withcorrect and incorrect bias.

FIG. 3. Ratio of depth doses with positive and negative (s) polarity
on various chambers.

ィࡣྠࡌࡶࡢ࡛࠶ࡿᚲせࡣ࡞࠸ࡀࠊ⥺㔞ィࢆࢫ࢟ࣕ࢖ࣉ࡜㟁ᅽࡢ㐺ṇ࡞᮲௳࡟⢭㏻ࡋ࡚࠾ࡃࡇ࡜ࢆ᥎

ࢽࣥࢢࢩࢫࢸ࣒࡟᥋⥆ࡍࡿሙྜࡣୗグࡢⅬ࡟ࡘ࠸ዡࡍࡿࠋࢹ࣮ࢱ཰㞟୰࡟᳨ฟჾࢆኚ᭦ࡋࡓሙྜࡸࠊ

࡚⪃៖ࡋ࡞ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋ

㟁఩ィࡢ㟁※ࢆධࢀࡿ๓࡟ࡣࠊࣂ࢖࢔ࢫࡢᚲせ᮲௳ࡢ☜ㄆࡀᚲせ࡛࠶ࡿࠋㄗࡗࡓࣂ࢖࢔ࢫ࡛౑⏝ࡍࡿ࡜

III.A.1.a. ᳨ฟჾࡢಖᣢල

᳨ฟჾࢆᦆയࡍࡿྍ⬟ᛶࡀ࠶ࡿࠋFig. 2 ࡣ₃㟁ࡀ㉳୍⯡ⓗ࡟ࠊࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡜ࢭࢵࢺ࡛㈍኎

ࡁ࡚࠸ࡿ㟁㞳⟽࡜ṇᖖ࡟ືసࡍࡿ㟁㞳⟽࡛ࠊタᐃࢤࡉࢀࡿ᳨ฟჾࡣ㛗㍈ࡢ㛗ࡉ࡜ෆᚄࡀ࡯ࡰྠࡌᑍἲ

࢖ࣥࡀṇࡋ࠸ሙྜ࡜ṇࡋࡃ࡞࠸ሙྜࡢ PDD ࢆ♧ࡋ࡛࠶ࡿࠋࡶࡋࡑ࠺࡛࡞࠸ሙྜ࡟ࡣࠊ㉮ᰝ᪉ྥࢆỴᐃ࡚࠸ࡿࠋࢫ࢟ࣕࣥࢹ࣮ࢱࡀ␗ᖖ࡞ࣃࢱ࣮ࣥࢆ♧ࡍሙࡍࡿ㝿࡟᳨ฟჾࡢᑍἲࡢᙳ㡪ࢆ⪃៖ࡍ࡭ࡁ࡛࠶ࡿࠋ

ྜࡸࠊࢫࣃ࢖ࢡ≧ࢆ♧ࡍሙྜࡣࠊࣂ࢖࢔ࢫࡸࢤ࢖ࣥ

ࡲࡓࠊ᳨ฟჾࡢᑍἲ࡜ࡣู࡟ࠊ㉮ᰝ᪉ྥࢆ⪃៖ࡋ࡞ࡀ㐺ษ࡛࡞࠸ྍ⬟ᛶࡀ࠶ࡿࠋࢫ࢟ࣕࣥ୰࡟ࡑࡢࡼ࠺

ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋࣅ࣮࣒ࡢ୰ᚰ㍈࡟㛵ࡋ࡚ࠊ᳨ฟჾ

࡞⌧㇟ࡀ㉳ࡁࡓሙྜࡣࠊࡍࡄ࡟

ࡢ㛗㍈ࡣ 3 ࡘࡢ᪉ྥ࡟タ⨨ྍ⬟࡛࠶ࡿࠋ(1) 㛗㍈ࡣჾࡢࣂ࢖࢔ࢫࡀ㐺ษ࠿ࢳ࢙ࢵࢡࡍ࡭ࡁ࡛࠶ࡿࠋ

ᐃࢆ୰Ṇࡋࠊ᳨ฟ

ࣅ࣮࣒㍈࡟ᆶ┤࡛ gun-target ᪉ྥ㸦y ᪉ྥ㸧࡟ᖹ⾜ࠊ(2) 㛗㍈ࡣࣅ࣮࣒㍈࡟ᆶ┤࡛ left-right ᪉ྥ㸦x ᪉ྥ㸧࡟ᖹ⾜ࠊ(3) ࣅ࣮࣒㍈࡟ᖹ⾜ࠊࡢ 3 ࡘ࡛࠶ࡿࠋ᳨ฟ

III.A.1.c. ᴟᛶ㟁㞳⟽⥺㔞ィࡢಙྕࡢᴟᛶࡣࠊ㧗㟁ᅽࣂ࢖࢔ࢫࡢ

ᐃ࡛㔜せᴟᛶ࡟ࡼࡾỴᐃࡉࢀࠊࡶࡋ㧗㟁ᅽࣂ࢖࢔ࢫࡢไᚚࡀ

࡜࡞ࡾࠊSec. IV A 4 a.࡛㆟ㄽࡉࢀࡿࠋ᳨ฟჾࡣࠊ㉮㟁఩ィ࡛⾜ࢃࢀ࡚࠸ࡿࡢ࡛࠶ࢀࡤၥ㢟ࡣ࡞࠸ࠋࡋ࠿

ᰝ᪉ྥ࡟ᑐࡋ࡚᭱ᑠࡢయ✚࡟࡞ࡿࡼ࠺࡟タ⨨ࡍ࡭ࡋࠊࢲ࢖࣮࢜ࢻ᳨ฟჾࡢಙྕࡢᴟᛶࡣࠊ᳨ฟჾࡢᵓ

ࡁ࡛࠶ࡿࠋࣅ࣮࣒㍈࡜ᖹ⾜࡟タ⨨ࡍࡿሙྜࡣ₃㟁ࡸ㐀࡟౫Ꮡࡍࡿࠋ〇㐀ᴗ⪅ࡣྠᵝࡢࣔࢹࣝࡢࢲ࢖࣮࢜

㟁㞳య✚እຠᯝ㸦Sec. III D 4 ࡛㆟ㄽࡉࢀࡿ㸧࡟ࡘ࠸ࢻ᳨ฟჾ࡟ᑐࡋ࡚୧᪉ࡢᴟᛶࢆᥦ♧ࡋ࡚ࡃࡿྍ⬟࡚⪃៖ࡍ࡭ࡁ࡛࠶ࡿࠋ

ᛶࡀ࠶ࡿࠋࡑࡢࡓࡵ࣮ࣘࢨ࣮ࡣࢲ࢖࣮࢜ࢻ᳨ฟჾࢆ

ჾࡢྥࡁࡣࣉࣟࣇ࢓࢖ࣝࡸ༙ᙳ㒊ศࡢ㉎ධࡍࡿ㝿ࡣࠊᡤ᭷ࡢ㟁఩ィ࡛౑⏝࡛ࡁࡿᴟᛶ࠿☜III.A.1.b. ༳ຍ㟁ᅽ㸦ࣂ࢖࢔ࢫ㸧ㄆࡋ࡞ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋ୍⯡ⓗ࡟ࠊ࡯࡜ࢇ࡝ࡢ᳨ฟ

࡯࡜ࢇ࡝ࡢ㟁㞳⟽⥺㔞ィࡣ 300 V ࠿ࡽ 400 V ࡢ㛫ჾࡣ࡝ࡕࡽࡢᴟᛶ࡛࠶ࡗ࡚ࡶ౑⏝ࡍࡿࡇ࡜ࡣ࡛ࡁ

ࡢ㟁ᅽ࡛౑⏝ࡉࢀࡿࠋ୍᪉ࠊࢲ࢖࣮࢜ࢻ᳨ฟჾࡢሙ

ࡿࡀࠊ࣮ࣘࢨ࣮ࡣ࡝ࡕࡽࡢᴟᛶ࡛ࡶ್ࡀ୍⮴ࡋ࡚࠸ྜࠊ㟁ᅽࡣ 0 V ࡟タᐃࡋ࡞ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋࢲ࢖࢔

ࡿࡇ࡜ࢆ☜ㄆࡋ࡞ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋFig. 3 ࡣᵝࠎ࡞ࣔࣥࢻ⥺㔞ィࡣ୍⯡ⓗ࡟ 100 V ࡛౑⏝ࡉࢀࡿࠋ᳨ฟ

᳨ฟჾ࡟࠾࠸࡚ᴟᛶࡀ㸩ࡢሙྜ࡜㸫ࡢሙྜ࡟ᚓࡽ

ჾࢆ㟁఩ィ࡟᥋⥆ࡍࡿ๓࡟ࠊ࣮ࣘࢨ࣮ࡣ᳨ฟჾࡢࢱ

ࢀࡓ PDD ࡢẚࢆ♧ࡋ࡚࠸ࡿࠋ1.0 ࡢ⥺ࡣᴟᛶຠᯝࡀ

28

III. スキャニングシステムのセットアップ

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)࡞࠸ࡇ࡜ࢆព࿡ࡋ࡚࠾ࡾࠊࡑࡢሙྜࡣ࡝ࡕࡽࡢᴟᛶ
࡛ࡶᐃࡀྍ⬟࡛࠶ࡿࡀࠊᗄࡘ࠿ࡢ᳨ฟჾࡣ኱ࡁ࡞

ᕪࢆ♧ࡋࡓࠋKim ࡽ 81 ࡣప⥺㔞⋡ࡢᐃࡢ㝿࡟ࡶࠊ

ᣦ㢌ᙧ㟁㞳⟽ࡢᴟᛶຠᯝࢆホ౯ࡍࡿᚲせࡀ࠶ࡿࡇ࡜ࢆⓎ⾲ࡋࡓࠋ୍⯡ⓗ࡟ࡣࠊᴟᛶ࡟ࡼࡾⱝᖸࡢ㐪࠸ࡀ㉳ࡇࡿࡇ࡜ࡣண᝿ࡉࢀࡿࡀࠊᴟᛶ࡟ࡼࡿᕪࡣ 0.5%௨ෆ࡟ᢚ࠼ࡿ࡭ࡁ࡛࠶ࡿࠋࢹ࣮ࢱ཰㞟ࡣࠊ⧞ࡾ㏉ࡋᐃ࡟࠾࠸࡚෌⌧ྍ⬟࡞୍㈏ࡋࡓ୍ࡘࡢᴟᛶ࡟࠾
࠸࡚⾜࠺ࡇ࡜ࢆ່ࡵࡿࠋFig. 3 ࡛♧ࡋࡓࡼ࠺࡟ࠊ୍
ࡘࡢᴟᛶ࡛ࡍ࡭࡚ࡢ

FIG. 4. BNC, TNC, and components of the triaxial cable.

ᐃࢆ⾜࠸ࠊᴟᛶຠᯝࡢᙳ㡪ࡀᑠࡉ࠸᳨ฟჾࢆ⏝࠸ࡿࡇ࡜࡛ࠊ඲యࡢㄗᕪࢆపࡃᢚ
࣮࡟ࡼࡾᛂ⟅ࡀኚ໬ࡍࡿࡓࡵࠊ ᐃ್࡟ᙳ㡪ࢆཬࡰ࠼ࡿࡇ࡜ࡀ࡛ࡁࡿࠋ

ࡍࠋࢲ࢖࣮࢜ࢻ᳨ฟჾࡢ࢚ࢿࣝࢠ࣮ᛂ⟅ࡣ 6 MV ගᏊ⥺ࠊ↷ᑕ㔝 4040 cm2 ࡢ᮲௳࡛ PDD ࢆ

III.A.1.d. ෌⤖ྜ࢖࢜ࣥ෌⤖ྜࡣ㧗㟁ᅽ㸦300 V ௨ୖ㸧࡛౑⏝ࡍࡿᐃࡋࠊ㟁㞳⟽⥺㔞ィࡢ PDD ࡜ẚ㍑ࡍࡿࡇ࡜࡛☜ㄆ࡛ࡁࡿࠋ
ᐃࡋࡓ PDD ࡢഴࡁࡀࢫ࢟ࣕࣥ⏝ࡢ㟁㞳⟽࡛ࡣ≉࡟ၥ㢟࡞࠸ࡀࠊ〇㐀ᴗ⪅ࡶࡋࠊࢲ࢖࣮࢜ࢻ᳨ฟჾ࡛

ࡀ᥎ዡࡋ࡚࠸ࡿ㟁ᅽࡢタᐃࡣ☜ㄆࡋ࡚࠾ࡃ࡭ࡁ࡛

㟁㞳⟽⥺㔞ィ࡛࠶ࡿࠋࡲࡓࠊ㟁㞳య✚ࡢᑠࡉ࡞㟁㞳⟽ࡢሙྜࠊᶆ‽ࡤࠊࡑࢀࡣ࢚ࢿࣝࢠ࣮ᛂ⟅ࡢኚ໬ࢆ⾲ࡋ࡚࠸ࡿࠋ୍

ⓗ࡞ 300 V ࡼࡾప࠸㟁ᅽࡀ᥎ዡࡉࢀ࡚࠸ࡿሙྜࡀ࠶

⯡ⓗ࡟ࠊ᳨ド࡟ࡼࡗ࡚≉ᐃࡢ⿵ṇἲࡀጇᙜ࡛࠶ࡿ࡜

ࡿࠋࡶࡋྍ⬟࡛࠶ࢀࡤࢫ࡛࢟ࣕࣥ౑⏝ࡍࡿ⥺㔞⋡࡛ࠊㄆࡵࡽࢀ࡞࠸㝈ࡾࡣࠊࢲ࢖࣮࢜ࢻ᳨ฟჾࡣ኱↷ᑕ㔝

82༳ຍ㟁ᅽࢆ᥎ዡࡢ༙ศࡢ್࡟ࡋ࡚෌⤖ྜຠᯝ ࢆ☜ࡢ PDD ࡢᐃࡋࡓࡶࡢࡼࡾࡶ⦆ࡸ࠿࡛࠶ࢀ

ᐃ࡟ࡣ౑⏝ࡍ࡭ࡁ࡛ࡣ࡞࠸ࠋ

ㄆࡋࠊ෌⤖ྜ⿵ṇࡢᚲせࡀ࡞࠸ࡇ࡜ࢆ☜ㄆࡍ࡭ࡁ࡛
III.A.2. ࢣ࣮ࣈࣝࠊࢥࢿࢡࢱࠊ࢔ࢲࣉࢱ࠶ࡿࠋ 㧗⢭ᗘ࡞ࢹ࣮ࢱ
III.A.1.e. ឤᗘᐃࢆ⾜࠺ࡓࡵ࡟ࡣࠊ㧗ရ㉁࡞ࢣ

࣮ࣈࣝ࡜㟁఩ィࡀᚲせ࡜࡞ࡿࠋࡶࡋࡑࢀࡽࢆ౑⏝ࡋ᳨ฟჾࡢឤᗘࡣᚲࡎࠊጇᙜ࡞ SN ẚ࡛ࠊ࠿ࡘಙྕ

࡞ࡅࢀࡤࠊᵝࠎ࡞せᅉ࡟ࡼࡾᐃ್ࡣ୙☜࠿࡞ࡶࡢ

ࡀ㣬࿴ࡋ࡞࠸⛬ᗘ࡟ࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋࢫ࢟ࣕࣥ

࡟࡞ࡿࠋࡑࢀࡽࡢせᅉࡢ࠸ࡃࡘ࠿ࡣࢣ࣮ࣈࣝࡢ㸦ಙࢆ⾜࠺๓࡟ࠊ᳨ฟჾࡢឤᗘ࡟㐺ࡋࡓ㟁఩ィࡢྕ㸧ᛅᐇᗘࡸࢥࢿࢡࢱࡢရ㉁ࠊ࢔ࢲࣉࢱ࡞࡝࡜ࡢ㐺ᐃࣞࣥࢪࢆ☜ㄆࡋ࡚࠾ࡃ࡭ࡁ࡛࠶ࡿࠋ᳨ฟჾࡢឤᗘࡣࠊ

ྜᛶ࡜㛵ಀࡀ࠶ࡿࠋ࣮ࣘࢨ࣮ࡣ௨ୗࡢ❶࡛㏙࡭ࡿ

᳨ฟჾࡢ〇㐀ᴗ⪅࠿ࡽධᡭ࡛ࡁࡿࠋࡲࡓࠊࣜࣇ࢓ࣞ

ᵝࠎ࡞ࢱ࢖ࣉࡢࢥࢿࢡࢱ࡟㛵ࡍࡿ▱㆑ࡀᚲせ࡟࡞ࣥࢫ⥺㔞ィ࡜ࣇ࢕࣮ࣝࢻ⥺㔞ィࡢឤᗘࡣྠ⛬ᗘ࡟ࡿࠋࡍ࡭ࡁ࡛࠶ࡿࠋࢫ࢟ࣕࣥ⏝ࡢࢯࣇࢺ࢙࢘࢔࡟ࡣࠊࣜ
ࣇ࢓ࣞࣥࢫ࡜ࣇ࢕࣮ࣝࢻࡢ㟁఩ィࡢಙྕࡀᆒ➼࡟

III.A.2.a. BNC ࢥࢿࢡࢱ࠾ࡼࡧ TNC ࢥࢿࢡࢱ࡞ࡿࡼ࠺⮬ືⓗ࡟ࢤ࢖ࣥࢆㄪᩚࡍࡿࡶࡢࡶ࠶ࡿࠋ↷BNC 㸦࠿ࡂ∎ᘧ Bayonet Neill - Concelman㸧ࡣᑕ㔝ࢧ࢖ࢬࢆኚ࠼ࡓ㝿࡟ࢤ࢖ࣥࡢ☜ㄆࢆ⾜࠺ࡇ࡜ࡑࡢⓎ᫂⪅࡟ࡕ࡞ࢇ࡛ྡ࡙ࡅࡽࢀ࡚࠾ࡾࠊ∎ࢆࡦࡡࡣ㔜せ࡛ࠊᙜ↛ࠊ࣮࢜ࣉࣥ↷ᑕ㔝࠿ࡽ࢙࢘ࢵࢪ↷ᑕࡾ࡞ࡀࡽࢫࢺࢵࣃ࣮࡟⿦╔ࡍࡿࢱ࢖ࣉࡢ࢔ࢱࢵࢳ

㔝࡟ኚ᭦ࡋࡓሙྜࡣࢤ࢖ࣥࡢㄪᩚࡀᚲせ࡜࡞ࡿࠋ࣓ࣥࢺࢆᣢࡘࠋࡇࢀࡣࠊ2 ㍈࠾ࡼࡧ 3 ㍈ࡢ୧᪉࡟ᑐ
ࡋ࡚〇㐀ࡉࢀ࡚࠸ࡿࠋTNC 㸦ࡡࡌᒣᘧ Threaded

III.A.1.f. ࢚ࢿࣝࢠ࣮ᛂ⟅୍⯡ⓗ࡟ࠊ㟁㞳⟽⥺㔞ィࡢ㧗࢚ࢿࣝࢠ࣮ගᏊ⥺࡟

Neill-Concelman㸧ࡣ BNC ࡢࡡࡌᒣᘧ࡛࠶ࡿࠋ୧⪅࡜ࡶ⥺㔞ᐃ࡟ࡼࡃ⏝࠸ࡽࢀࠊከᑡࡢ័ࢀࡀᚲせ࡛ᑐࡍࡿ࢚ࢿࣝࢠ࣮ᛂ⟅ࡣ࡯ࡰ୍ᐃ࡛ࠊ≉࡟⿵ṇࢆ⾜࠶ࡿࠋFig. 4 ࡟᥋⥆㒊ศࡢ౛ࢆ♧ࡋࡓࡀࠊBNC ࡜ TNC

࠺ᚲせࡣ࡞࠸ࠋ୍᪉ࠊࢲ࢖࣮࢜ࢻ᳨ฟჾࡣ࢚ࢿࣝࢠ

ࢥࢿࢡࢱࡢእぢࡣⰋࡃఝ࡚࠸ࡿࠋࢥࢿࢡࢱࡢ୰࡛ࡶ

29

医学物理 第 33 巻 第 1 号

III. スキャニングシステムのセットアップ᥋⥆㒊ࡢ✀㢮㸦BNCࠊTNC ࡞࡝㸧ࠊ࢜ࢫ࣭࣓ࢫࠊᑟ
యࡢ✀㢮㸦2 ㍈ࠊ3 ㍈㸧࡞࡝ᵝࠎ࡞⤌ࡳྜࢃࡏࡀ࠶
ࡿࠋ≉࡟ᣓᘼෆࡢ౛࡟ᣲࡆࡓࡶࡢࡣࠊࢫ࢟ࣕࢽࣥࢢ
ࢱࣥࢡ࡛౑⏝ࡉࢀࡿ᳨ฟჾ࡜㟁఩ィࢆ᥋⥆ࡍࡿ㒊ศ࡟ᗈࡃ౑⏝ࡉࢀ࡚࠸ࡿࠋ࠶ࡿ〇㐀ᴗ⪅ࡣࠕ3 ㍈ᆺࠖ
ࢆᨵⰋࡋࡓࢥࢿࢡࢱࢆ᥇⏝ࡋ࡚࠾ࡾࠊࡇࡢࢥࢿࢡࢱ
ࡢぢࡓ┠ࡣ 2 ㍈ࡔࡀࠊ㟁ᴟࡀࢥࢿࢡࢱ࡟ෆⶶࡉࢀ࡚
࠸ࡿࠋࢥࢿࢡࢱࡢヲ⣽࡟ࡘ࠸࡚ࡣ〇㐀ᴗ⪅㸦CNMC♫ࠊStandard Imaging ♫ࠊ PTW ♫ࠊ Wellhöfer ♫࡞࡝㸧࠿ࡽ☜ㄆ࡛ࡁࡿࠋ࠶ࡽ࠿ࡌࡵ〇㐀ᴗ⪅ࡈ࡜ࡢࢥࢿࢡࢱࡢᙧ≧ࢆᢕᥱࡋ࡚࠾ࡃࡇ࡜࡟ࡼࡾࠊᑗ᮶〇㐀

FIG. 5. Effect of cable length in radiation beam. The cables are ofᴗ⪅࠿ࡽ᪂ࡋ࠸᳨ฟჾࢆ㉎ධࡍࡿሙྜ࡟ᙺ࡟❧ࡘࠋdifferent types from various manufacturers.

x࢜ࢫ: ୰ᚰࡢᑟ⥺ࡀࣆࣥ≧ࡢࡶࡢx

࣓ࢫ: ୰ᚰࡢᑟ⥺ࡀࢯࢣࢵࢺ࣮࣍ࣝ≧ࡢࡶࡢx

3 ㍈: 3 ᮏࡢఏᑟయࡀྠᚰ≧࡟㓄⨨ࡉࢀࡓࠊࢣ࣮

᥋⥆ࡢ㝿࡟᭱ࡶⰋࡃ㉳ࡁࡿㄗࡾࡣࠊ2 ㍈ࡢ BNC ࢥࢿࣈࣝࡶࡋࡃࡣࢥࢿࢡࢱ

ࢡࢱ࡜ 3 ㍈ࡢ BNC ࢥࢿࢡࢱࢆ↓⌮ࡸࡾ⧅ࡆࡿࡇ࡜

2 ㍈: 2 ᮏࡢఏᑟయࡀྠᚰ≧࡟㓄⨨ࡉࢀࡓࠊࢣ࣮

࡛࠶ࡿࠋࡇࡢሙྜࠊ(1) ࢥࢿࢡࢱ㒊ศࡀ◚ᦆࡍࡿࠊࣈࣝࡶࡋࡃࡣࢥࢿࢡࢱ

(2)

࢔ࢲࣉࢱ: ␗࡞ࡿ✀㢮ࡢࢥࢿࢡࢱྠኈࢆ᥋⥆ࡍࡋ᳨࡚ฟჾࡸ㟁఩ィࡀ◚ᦆࡍࡿࠊ࡞࡝ࡢ㔜኱࡞஦ᨾࡿࡓࡵࡢࠊኚ᥮⏝ࢥࢿࢡࢱࡶࡋࡃࡣ▷࠸ࢣ࣮ࣈࡀ㉳ࡁࡿࠋࡲࡓࠊࢣ࣮ࣈࣝࢆࡡࡌࡿࠊ᭤ࡆࡿࠊຊࢆ

ࣝຍ࠼ࡿ࡞࡝ࡢ⾜Ⅽࡣࢩ࣮ࣙࢺࡢཎᅉ࡜࡞ࡿࡓࡵࠊ⤯xx㟁఩ィࡢ㧗㟁ᅽࡀㄗࡗࡓ᥋⥆࡟ࡼࡾࢩ࣮ࣙࢺ

ᑐ࡟⾜ࡗ࡚ࡣ࡞ࡽ࡞࠸ࠋ୙㐺ษ࡞⤌ࡳྜࢃࡏ࡛ࡶಙ
III.A.2.b. ୍⯡ⓗ࡞᥋⥆࢚࣮ࣛ࡯࡜ࢇ࡝ࡢ⥺㔞ᐃ࠾ࡼࡧࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ

ྕࢆྲྀᚓࡍࡿࡇ࡜ࡀ࡛ࡁࡿ࠿ࡶࡋࢀ࡞࠸ࡀࠊࡑࡢࡼ
࠺࡞ಙྕ࡟ࡣ෌⌧ᛶࡀ࡞࠸ࠋ

࣒࡟࠾࠸࡚ 3 ㍈ࢣ࣮ࣈࣝࡀ᥇⏝ࡉࢀ࡚࠸ࡿࠋ㟁㞳⟽⥺㔞ィࡣ 3 ㍈ࢣ࣮ࣈࣝ࡟┤᥋᥋⥆࡛ࡁࡿࡀࠊ࠸ࡃࡘ

III.A.2.c. ₃ࢀ㟁ὶ࠿ࡢ〇㐀ᴗ⪅ࡀ⏝࠸࡚࠸ࡿ 3 ㍈ࢣ࣮ࣈࣝࡢሙྜࠊ㏻

ࢹ࣮ࢱ཰㞟࡟౑⏝ࡍࡿࢣ࣮ࣈࣝࡣࠊࢣ࣮ࣈࣝࡢရ

ᖖࡢ㟁㞳⟽⥺㔞ィࡣ᥋⥆࡛ࡁࡎࠊᑓ⏝ࡢ࢔ࢲࣉࢱࡀ

㉁ࡸྲྀᢅ≧ἣࠊ⥔ᣢ≧ែ࡟ࡼࡾ୍ᐃ㔞ࡢ₃ࢀ㟁ὶࡀᚲせ࡜࡞ࡿࠋPTW ♫ࡣ≉Ṧ࡞ 3 ㍈ࢣ࣮ࣈࣝࢆ᥇⏝ࡋ

Ⓨ⏕ࡍࡿࠋࡁࡘࡃࡡࡌ᭤ࡆࡽࢀࡓࢣ࣮ࣈࣝࢆ౑⏝ࡋ࡚࠸ࡿᴗ⪅ࡢ୍ࡘ࡛࠶ࡿࠋࢲ࢖࣮࢜ࢻࡢሙྜࠊ࢔ࣀ

ࡓሙྜࠊࣀ࢖ࢬࡀⓎ⏕ࡍࡿࠋࡓ࠸࡚࠸ࡢᕷ㈍ࢣ࣮ࣈ

࣮ࢻ࡜࢝ࢯ࣮ࢻࡢ 2 ࡘࡢ㟁ᴟࡀ࠶ࡾࠊ2 ㍈ࢣ࣮ࣈࣝࣝࡢ₃ࢀ㟁ὶࡣ 10í13–10í14 A ⛬ᗘ࡛࠶ࡿ 83-85ࠋࢣ࣮ࡀᚲせ࡟࡞ࡿࠋ㟁㞳⟽⥺㔞ィࡢሙྜ 3 ࡘࡢ㟁ᴟ㸦㞟ࣈࣝࡢ᭤ࡆࠊࡡࡌࡾࠊ஘㞧࡞ಖ⟶࡞࡝࡟ࡼࡾࠊ₃ࢀ㟁ᴟࠊ࣮࢞ࢻࠊHV ࣂ࢖࢔ࢫ㸧ࡀ࠶ࡿࡓࡵࠊ3 ㍈ࢣ

㟁ὶࡣ᫂ࡽ࠿࡟኱ࡁࡃ࡞ࡿࠋᑠ↷ᑕ㔝ࡸ↷ᑕ㔝እࡢ࣮ࣈࣝࡀᚲせ࡟࡞ࡿࠋࢲ࢖࣮࢜ࢻ᳨ฟჾࡢሙྜࠊ㐺ᐃࡢ㝿࡟ࡣࠊ ᐃࡢಙྕ࡟ẚ࡭ࣀ࢖ࢬࡀከࡃ࡞ࡾ

ษ࡞࢔ࢲࣉࢱࢆ౑⏝ࡍࡿࡇ࡜࡟ࡼࡾ 3 ㍈ࢣ࣮ࣈࣝࢆ

࠺ࡿࠋ₃ࢀ㟁ὶࡣ୍⯡ⓗ࡟ࠊࢣ࣮ࣈࣝࡢရ㉁ࠊ↷ᑕ౑⏝࡛ࡁࡿࡀࠊ㟁㞳⟽⥺㔞ィ࡜ 2 ㍈ࢣ࣮ࣈࣝࡣ᥋⥆ࡉࢀ࡚࠸ࡿࢣ࣮ࣈࣝࡢ㛗ࡉࠊࢥࢿࢡࢱ࡟౫Ꮡࡍࡿࠋ

ࡍࡿࡇ࡜ࡣ࡛ࡁ࡞࠸ࠋࡉࡽ࡟ࠊ㟁㞳⟽⥺㔞ィࢆ౑⏝࠸ࡃࡘ࠿ࡢ㟁఩ィࡣࠊ㞽Ⅼㄪᩚ࡟ࡼࡾ₃ࢀ㟁ὶࢆ࢜ࡍࡿሙྜࡣ㧗㟁ᅽࢆ༳ຍࡍࡿࡓࡵࠊேࡸ㟁Ꮚᶵჾ࡬ࣇࢭࢵࢺࡍࡿࡇ࡜ࡀ࡛ࡁࡿࠋ㞽Ⅼㄪᩚࡣࣅ࣮࣒࢜ࣇ

ឤ㟁ࡍࡿࡇ࡜ࡀ࡞࠸ࡼ࠺࡟ᚲࡎὀពࢆࡋ࡞ࡅࢀࡤ

ࡢ≧ែ࡛⾜࠺࡭ࡁ࡛࠶ࡿࠋ᳨ฟჾ࣐࢘ࣥࢺࡢྥࡁ࡟

࡞ࡽ࡞࠸ࠋࡲࡓࠊࢣ࣮ࣈࣝ࡞࡝ࢆ᥋⥆ࡍࡿ㝿ࡣ㟁ᅽࡼࡗ࡚↷ᑕࡉࢀࡿࢣ࣮ࣈࣝࡢ㛗ࡉࡀኚࢃࡿࡓࡵࠊ₃ࢆⴠ࡜ࡋࡓ≧ែ࡛⾜ࢃ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋ

ࢀ㟁ὶࡢ㔞࡟ᙳ㡪ࢆ୚࠼ࡿࠋ

㟁㞳⟽⥺㔞ィ⏝ࡢ㟁఩ィ࡜ࢲ࢖࣮࢜ࢻ᳨ฟჾࡢ

30

Fig. 5 ࡣࠊ␗࡞ࡿ〇㐀ᴗ⪅ࡢᵝࠎ࡞✀㢮ࡢࢣ࣮ࣈ

III. スキャニングシステムのセットアップ

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)ࣝ࡟࠾ࡅࡿࠊ↷ᑕ㔝ෆ࡟ධࡿࢣ࣮ࣈࣝࡢ㛗ࡉ࡟ࡼࡿᐃ್ࡢኚ໬ࢆ♧ࡋ࡚࠸ࡿࠋDas ࡽ86ࡣࠊ㟁Ꮚ⥺ࡢ

ᐃ᫬࡟ࡣ↷ᑕ㔝ෆ࡟ධࡿࢣ࣮ࣈࣝࡢ㛗ࡉࡀᐃ➃Ꮚࡢ㟁ᅽࡣྠࡌ࠿ࡑࢀ࡟㏆࠸ࠋࡶࡋࠊ1 mV ⛬ᗘࡢධຊ࢜ࣇࢭࢵࢺ㟁ᅽࡀ⏕ࡌࡿ࡜ࠊ㟁㞳⟽⥺㔞ィ࡟࠾࠸࡚₃ࢀ㟁ὶࡢࡼ࠺࡞ຠᯝࢆ⏕ࡌࡿࠋࡶࡋࠊࢲ࢖

್࡟㔜኱࡞ᙳ㡪ࢆཬࡰࡍ࡜ሗ࿌ࡋ࡚࠸ࡿࠋࡑࡢࡓࡵࠊ

࣮࢜ࢻ᳨ฟჾ࡛

ࢣ࣮ࣈࣝࡀ↷ᑕ㔝ෆ࡟ᗈ࠸⠊ᅖ࡛ྵࡲࢀࡿሙྜࠊ≉ࡾ┤᥋ㄞࡳ್࡟್ࡀຍ࠼ࡽࢀ࡚ࡋࡲ࠺ࠋ

ᐃࢆ⾜࠺࡜ࠊධຊ࢜ࣇࢭࢵࢺ࡟ࡼ

ู࡞⪃៖ࡀᚲせ࡜࡞ࡿࠋࢫ࢟ࣕࣥࢆ⾜࠺๓࡟ࠊỈ୰࡟ධࡿࢣ࣮ࣈࣝࡢ᳨ฟჾ࡟㏆࠸㒊ศ࡟യࡸࠊࡁࡘࡃ

III.A.3.d. 㐃⥆ᛶ᭤ࡀࡿ㒊ศࡀ࡞࠸࠿ㄪ࡭࡚࠾ࡃ࡭ࡁ࡛࠶ࡿࠋࢣ࣮ࣈ

ᑠయ✚ࡢ㟁㞳⟽ࡣప࠸ࣂ࢖࢔ࢫ㟁ᅽ࡛ࡶ࢖࢜ࣥ

ࣝࡢ‴᭤ࡸᑠࡉ࡞യࡣ᩿⥺ࡢཎᅉ࡜࡞ࡾࠊ⤯⦕ㄏᑟࡀ཰㞟ࡉࢀࡿ࡜࠸࠺ၥ㢟ࡀ࠶ࡿࠋᩘ mV ࡢ࣮࢞ࢻ࡜

యࡸࣀ࢖ࢬపῶᮦࡀࢲ࣓࣮ࢪࢆཷࡅࡓሙྜ࡜ྠᵝ㟁ᴟࡢ㛫࡟⏕ࡌࡿ⛬ᗘࡢ㟁ᅽ࡛ࡶࠊ㣬࿴ࡋ࡞࠸⛬ᗘ࡛ࠊỈ࡟ỿࡵ࡚

ࡢ࢖࢜ࣥࡢ཰㞟ࡀྍ⬟࡛࠶ࡿࠋࡇࡢ⛬ᗘࡢ㟁ᅽࡣࠊᐃࢆ⾜࠺࡜㟁఩ィ࡟㟁Ẽⓗ࡞ၥ㢟㟁఩ィࡢ࣮࢞ࢻ࡜㟁ᴟ㛫ࡢධຊ࢜ࣇࢭࢵࢺ࡜ࡋ࡚

ࢆ㉳ࡇࡍࠋᏑᅾࡍࡿࠋࡑࡢࡓࡵࠊࣂ࢖࢔ࢫ㟁ᅽࡀṇ☜࡟༳ຍࡉ
III.A.3. 㟁఩ィࢀ࡚࠸࡞࠸ሙྜࡸࠊ㟁㞳⟽ࡢ㧗ᅽ㟁ᴟࡀࡁࡕࢇ࡜᥋ ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡟⏝࠸ࡽࢀࡿ㟁఩ィࡣࠊᗈ
í6࠸ࢲ࢖ࢼ࣑ࢵࢡࣞࣥࢪࢆᣢࡕࠊ10 ࠿ࡽ 10í14⥆ࡉࢀ࡚࠸࡞࠸ሙྜ࡛ࡶࠊ㟁Ⲵࡣᐃࡉࢀ࡚ࡋࡲ࠺ࠋC ࡢ⠊౵くⓗ࡞㸦ᶵᲔⓗ࡞㸧ࢸࢫࢺ࡜ࡣู࡟ࠊ㐃⥆ᛶࢆᐃࡍࡿࡇ࡜ࡀ࡛ࡁࡿࠋࢫ࢟ࣕࢽࣥࢢࢆಖドࡍࡿࡓࡵࡢࢸࢫࢺࡀ࠶ࡿࠋࡶࡋ㟁఩ィ࡜ࣂ࢖࢔ᅖࡢ㟁Ⲵࢆ⾜࠺๓࡟㟁఩ィࡢ㞽Ⅼㄪᩚࢆ⾜࠺࡭ࡁ࡛࠶ࡿࠋࡲࡓࠊ

ࢫࢆㄪᩚ࡛ࡁࡿሙྜࠊࣅ࣮࣒ࢹ࣮ࢱࡢ

౑⏝ࡍࡿ๓࡟

ࢆኚ᭦ࡋࠊ ᐃ್ࡢᴟᛶࡀኚ໬ࡍࡿ࠿☜ㄆࡍࡿࠋࡶ

ᐃࣞࣥࢪࢆኚ᭦ࡋ࡚ࡶᛂ⟅㸦

ᐃ್㸧

ᐃ୰࡟ᴟᛶ

ࡢ┤⥺ᛶࡀಖࡓࢀ࡚࠸ࡿࡇ࡜ࢆ☜ㄆࡋ࡚࠾ࡃ࡭ࡁ

ࡋࠊ㏻ಙࡀ㏵⤯࠼࡚࠸ࡿሙྜࡸࠊධຊ࢜ࣇࢭࢵࢺࡀ

࡛࠶ࡿࠋㄞࡳ್ࡣࠊ᳨ฟჾ࡜㟁఩ィࡢᛂ⟅ࢆྜᡂࡋ࠶ࡿሙྜࡣᴟᛶࢆኚ࠼࡚ࡶಙྕࡣኚ໬ࡋ࡞࠸ࡓࡵࠊ

ࡓ್࡛࠶ࡿࠋ୍⯡ⓗ࡟᳨ฟჾࡢᛂ⟅ࡣ࣐࢖ࢡࣟ⛊ࡔᴟᛶ࡜࡜ࡶ࡟ಙྕࡢኚ໬ࡀ☜ㄆ࡛ࡁࢀࡤࠊ㐃⥆ᛶࡀࡀࠊ㟁఩ィࡢᛂ⟅ࡣ࣑ࣜ⛊࡛࠶ࡿࡓࡵࠊ㟁఩ィࡢᛂಖドࡉࢀࡿࠋ

⟅ࡣࢫ࢟ࣕࢽࣥࢢ࡟࠾࠸࡚ᴟࡵ࡚㔜せ࡜࡞ࡿࠋ 㐃⥆ᛶࡀಖ࡚࡞࠸஦౛࡜ࡋ࡚ࠊỈ୰࡟᳨ฟჾ࡜ࢣ
࣮ࣈࣝࢆධࢀࡓሙྜࡀ⪃࠼ࡽࢀࡿࠋࢥࢿࢡࢱࡸ࢔ࢲ

III.A.3.a.

ᐃࡢᴟᛶࣉࢱࠊࢣ࣮ࣈࣝ࡞࡝ࡢྲྀࡾᢅ࠸ࡀ㐺ษ࡛࡞࠸ሙྜࠊ

㟁఩ィࡢධຊᴟᛶࡣ 2 ᴟᆺ࡜ 1 ᴟᆺ࡟ศࡅࡽࢀࡿࠋ

ṇࡋ࠸᮲௳ୗ࡛ࡶ㟁㞳⟽ࡢࣂ࢖࢔ࢫ㟁ᅽࡀࢩ࣮ࣙ

2 ᴟᆺࡣṇ࡜㈇ࡢ୧ᴟᛶ࡛

ᐃࡀྍ⬟ࡔࡀࠊ1 ᴟᆺࢺࡋ࡚ࡋࡲ࠺ࡇ࡜ࡀ࠶ࡿࠋ௨ୗࡢ❶࡛ヲࡋࡃ㏙࡭ࡿࡣ∦᪉ࡢᴟᛶࡢ㟁Ⲵࡋ࠿ᐃࡍࡿࡇ࡜ࡣ࡛ࡁ࡞࠸ࠋ

✵୰࠾ࡼࡧỈ୰࡛ࡢᐃࡢẚ㍑࡛ࡣࠊ㐪࠸ࢆ♧ࡍࡇヲࡋࡃࡣࠊୖグࡢᴟᛶࡢ㒊ศ㸦III.A.1.c.㸧࡜₃ࢀࡢ࡜ࡀ࠶ࡿࠋࡲࡓࠊ๓㏙ࡢᴟᛶ཯㌿ࢸࢫࢺ࡛ࡶࡑࢀࡽ

㒊ศ㸦III.A.2.c.㸧ࢆཧ↷ࠋࡢၥ㢟ࡣ᫂ࡽ࠿࡟࡞ࡿࠋ

III.A.3.b. ධຊ࢜ࣇࢭࢵࢺ㟁ὶ㸦₃ࢀ㟁ὶ㸧

III.A.3.e. ࢤ࢖ࣥ࡜⮬ືࣞࣥࢪㄪᩚ

ᐃ್࡟ࡣᐃಙྕ࡟஺ࡌࡾࠊ₃ࢀ㟁ὶࡶಙྕ࡜

ࡋ࡚ྵࡲࢀ࡚࠸ࡿࠋࡓ࠸࡚࠸ࡢ

㟁఩ィࡣᵝࠎ࡞ࢤ࢖ࣥࡢ㑅ᢥࡀྍ⬟࡛ࠊ᳨ฟჾࡢ

ᐃ᮲௳࡛࠶ࢀࡤ₃ឤᗘࡢ㐪࠸࡟ྜࢃࡏ࡚㑅ᢥࡍࡿࡇ࡜ࡀ࡛ࡁࡿࠋࢤ࢖

ࢀ㟁ὶࡣၥ㢟࡟࡞ࡽ࡞࠸ࡀࠊୖグࡢ࡜࠾ࡾࠊឤᗘࡢ

ࣥࡣ⮬ືࡶࡋࡃࡣᡭື࡛タᐃࡍࡿࡇ࡜ࡀ࡛ࡁࠊᡭື

ప࠸ᑠయ✚ࡢ⥺㔞ィ࡟ࡼࡿࣉࣟࣇ࢓࢖ࣝ

࡛ࢤ࢖ࣥࢆタᐃࡍࡿሙྜࠊᇶ‽Ⅼ࡛ࣇ࢕࣮ࣝࢻ⥺㔞ᐃࡢ㝿࡟ࡣၥ㢟࡜࡞ࡿሙྜࡀ࠶ࡿࠋ

ィ࡜ࣜࣇ࢓ࣞࣥࢫ⥺㔞ィࡢឤᗘࡀ࡯ࡰ➼ࡋࡃ࡞ࡿࡼ࠺࡟タᐃࡍࡿ࡭ࡁ࡛࠶ࡿࠋ

III.A.3.c. ධຊ࢜ࣇࢭࢵࢺ㟁ᅽ 㟁఩ィࡶࡲࡓࠊ཯㌿ධຊ࡜㠀཯㌿ධຊ࡜ࡢ㛫࡟ධຊ࢜ࣇࢭࢵࢺ㟁ᅽࢆ⏕ࡌࡿࠋ⌮ㄽⓗ࡟ࡣ஧ࡘࡢධຊ

III.A.3.f. ಙྕࡢ㣬࿴ึᮇタィ࡛ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡟⤌ࡳ㎸ࡲࢀ

31

医学物理 第 33 巻 第 1 号

࡚࠸࡞࠸᳨ฟჾࢆ౑⏝ࡍࡿሙྜࠊ㟁఩ィࡢࢪ࠿ࡽ

III. スキャニングシステムのセットアップᐃࣞࣥୖ࡟ࢱࣥࢡࢆ⨨࠸࡚ࡣ࠸ࡅ࡞࠸ࠋ୍⯡ⓗ࡟ࡣࠊỈࢆᐃ್ࡀእࢀ࡚ࡋࡲ࠺ሙྜࡀ࠶ࡿࠋᑠయ✚ࡢ㈓ࡵࡓࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢ㔜ࡉࡣ 280 kg ㏆ࡃ࡟㟁㞳⟽ࡢሙྜࠊឤᗘࡣ 0.5 nC/Gy ࡛࠶ࡿࠊࢲ࢖࣮࢜

࡞ࡾࠊᐷྎࡢ㔜㔞ไ㝈ࢆ㉸࠼࡚ࡋࡲ࠺ࠋࡑࡢࡓࡵࠊ

ࢻ࡛ࡣ 50 nC/Gy ࠿ࡑࢀ௨ୖࡢሙྜࡶ࠶ࡾࠊឤᗘᕪ

࡯࡜ࢇ࡝ࡢ〇㐀ᴗ⪅ࡣࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࢆ㈓Ỉ

ࡀ 100 ಸ㏆ࡃ࡟࡞ࡿࠋࡶࡋࠊᑠయ✚ࡢ㟁㞳⟽ࡢࢱࣥࢡࡢୖ࡟ಖᣢ࡛ࡁࡿࡼ࠺࡞ࢩࢫࢸ࣒࠿ࠊࡶࡋࡃ

ᐃࣞࣥࢪ࡛ࢲ࢖࣮࢜ࢻ᳨ฟჾࢆ౑⏝ࡍࡿ࡜ࠊಙྕࡣᐜ

ࡣࡑࢀࡽࢆูࠎ࡟ࡋ࡚ᑓ⏝ࡢ㡹୔࡞ಖᣢල࡛ᨭ࠼

᫆࡟㣬࿴ࡋ࡚ࡋࡲ࠺ࠋಙྕࡢ㣬࿴≧ἣ࠿ࡽࠊࢫ࢟ࣕ

ࡿࡼ࠺࡞㡹୔࡞ࢩࢫࢸ࣒ࢆᥦ౪ࡋ࡚࠸ࡿࠋࢫ࢟ࣕࢽ

ࣥࡢ␗ᖖࢆศᯒࡍ࡭ࡁ࡛࠶ࡿࠋࡇࡢࡼ࠺࡞≧ἣࡣࠊࣥࢢࢱࣥࢡࡣࠊ᳨ฟჾࢆື࠿ࡍ㝿࡟㥑ື㒊ࡢືࡁࡀ࢙࢘ࢵࢪࣉࣟࣇ࢓࢖ࣝࡢࡼ࠺࡟ಙྕࡀ኱ࡁࡃኚ໬

᭱ᑠ࡟࡞ࡿࡼ࠺࡟タ⨨ࡍ࡭ࡁ࡛࠶ࡿࠋ౛࠼ࡤࠊከࡃ

ࡍࡿ

ࡢ 3D ࢩࢫࢸ࣒࡛ࡣ x ᪉ྥࡢࢫ࢟ࣕࣥࡣ᳨ฟჾࡢࡳ

ᐃ࡛Ⓨ⏕ࡍࡿࠋ

ࡀ㥑ື࢔࣮࣒࡟ἢࡗ࡚㥑ືࡍࡿࡀࠊy ᪉ྥࡢࢫ࢟ࣕ
III.A.3.g. ಙྕࣀ࢖ࢬẚࣥࡢ㝿ࡣ࢔࣮࣒඲యࢆື࠿ࡍᚲせࡀ࠶ࡿࠋx ᪉ྥࡢ 㣬࿴࡜ࡣ㏫࡟ࠊಙྕ୙㊊ࡢࡓࡵ࡟ࣀ࢖ࢬࡀಙྕࡼ

ࢫ࡛࢟ࣕࣥࡣ㥑ື㒊ศࡀᑡ࡞࠸ࡓࡵࠊỈ㠃ࡀᦂࢀࡿࡾ኱ࡁࡃ࡞ࡿሙྜࠊಙྕࣀ࢖ࢬ㸦SN㸧ẚࡣᑠࡉࡃ࡞

๭ྜࡀᑡ࡞ࡃࠊࡼࡾࡁࢀ࠸࡞ࢹ࣮ࢱ཰㞟ࡀྍ⬟࡜࡞ࡿࠋ㐺ษ࡞᳨ฟჾ࡜ࢤ࢖ࣥࠊపࣀ࢖ࢬࡢ㧗ရ㉁ࢣ࣮

ࡿࠋࡲࡓࠊ἞⒪ィ⏬⿦⨨ෆ࡛ࡢᗙᶆ࡜ࢫ࢟ࣕࣥࡢ㝿ࣈࣝࢆ㑅ࡧࠊ㧗࠸ SN ẚࢆಖࡘ࡭ࡁ࡛࠶ࡿࠋගᏊ⥺ࡢᗙᶆࡀ୍⮴ࡍࡿࡼ࠺࡟ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࢆタࡢ༙ᙳ㒊ศࡢ

ᐃࡸࠊ㟁Ꮚ⥺ࡢไືᨺᑕ࡟ࡼࡿࢸ࣮

⨨ࡍࡿ࡭ࡁ࡛࠶ࡿࠋࢥ࣑ࢵࢩࣙࢽࣥࢢ୰࡛ࡢᗙᶆࡢ

ᐃࡢ㝿࡟ࠊࢫ࢟ࣕࣥࢹ࣮ࢱࡀ⁥ࡽ࠿࡛࡞ࣛ࣋ࣜࣥࢢࡢኚ᭦ࡣࠊవィ࡞᫬㛫ࢆ⏕ࡌࡉࡏࠊΰ஘

ࣝ㒊ศࡢ࠸ሙྜࡣ SN ẚࢆ☜ㄆࡍࡿ࡭ࡁ࡛࠶ࡿࠋࢫ࢟ࣕࢽࣥ

ࢆᣍࡃࡓࡵ⾜࠺࡭ࡁ࡛ࡣ࡞࠸ࠋ

ࢢࡢ㝿࡟ࡣ SN ẚࢆᑡ࡞ࡃ࡜ࡶ 100 ௨ୖ࡟⥔ᣢࡍࡿ ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢཎⅬ㸦0,0,0㸧ࡣ⿦⨨ࡢ࢔࢖ࡇ࡜ࡀⰋ࠸ᇶ‽࡜࡞ࡿࠋࢯࢭࣥࢱ࡟㏆࡙ࡅࡿ࡭ࡁ࡛ࠊ㞳ࢀ࡚࠸ࡿ࡜኱ࡁ࡞↷ᑕ㔝ࢆ

III.A.3.h. ᛂ⟅᫬㛫ᐃࡍࡿ㝿࡟ၥ㢟࡜࡞ࡿࡇ࡜ࡀ࠶ࡿࠋx ㍈ࡣ࣮ࣞࢨࡢ cross-plane㸦left-right ᪉ྥ㸧࡟ྜࢃࡏࠊy㟁఩ィࡢᛂ⟅᫬㛫ࡣࠊಙྕࡢኚ໬ࡢ᳨ฟ㏿ᗘࢆỴ

㍈ࡣ in-plane㸦gun-target ᪉ྥ㸧࡟ྜࢃࡏࡿࡢࡀⰋ࠸

ᐃࡍࡿࠋࣅ࣮࣒ࡢ㎶⦕㒊ศ࡛ࢫ࢟ࣕࣥ㏿ᗘࡀ㏿࠸ሙ᪉ἲ࡛࠶ࡿࠋx ࣉࣟࣇ࢓࢖ࣝ࡜ y ࣉࣟࣇ࢓࢖ࣝࡢᕪ

ྜࠊ᳨ฟჾࡢಙྕࡣᛴ㏿࡟ኚ໬ࡍࡿࠋࡶࡋᛂ⟅᫬㛫ࡣ 1%⛬ᗘぢ㎸ࡲࢀࠊࡓ࠸࡚࠸ࡢ⿦⨨ࡣࡇࡢ࠶ࡓࡾ

ࡀ㛗ࡃࢫ࢟ࣕࣥ㏿ᗘࡀ㏿࠸ሙྜࠊ༙ᙳ㒊ศࡢᙧ≧ࡣࡀチᐜ್࡜࡞ࡿࠋSiemens ♫ࡢ἞⒪⿦⨨ࡢࡼ࠺࡟ࣅ

ᗈࡀࡿࠋࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡟ࡼࡾ␗࡞ࡿ࢔ࣉࣟ

࣮࣒ࢫࢸ࢔ࣜࣥࢢࡀ in-plane ᪉ྥࡢࡳࡢሙྜࡣࠊx࣮ࢳ࡜ከᵝ࡞ᛂ⟅᫬㛫ࢆᣢࡘࡓࡵࠊᩘ್ࢆ୍⯡໬ࡋ᪉ྥࡢࣉࣟࣇ࢓࢖ࣝࡣࡼࡾ⁥ࡽ࠿࡟࡞ࡾࠊၥ㢟ࡣᑡ࡚ᥦ౪ࡍࡿࡇ࡜ࡣᅔ㞴࡛࠶ࡿࠋ⌧ᅾࡢࢫ࢟ࣕࢽࣥࢢ

࡞ࡃ࡞ࡿࠋࡲࡓࠊྍ⬟࡛࠶ࢀࡤ〇㐀ᴗ⪅ࡀᥦ౪ࡍࡿ

ࢩࢫࢸ࣒ࡢ඾ᆺⓗ࡞ᛂ⟅᫬㛫ࡣ 10 ms ௨ୗ࡛ࠊࢫ࢟

ᐃ㍈ࡢㄪᩚ⿦⨨ࢆ౑⏝ࡍ࡭ࡁ࡛࠶ࡿࠋከࡃࡢࢫ࢟

ࣕࣥ㏿ᗘࡣ 1 ࠿ࡽ 500 mm/s ࡛⛣ື࡛ࡁࡿࡇ࡜࠿ࡽࠊ

ࣕࢽࣥࢢࢩࢫࢸ࣒࡟ࡣ xࠊyࠊz ࡢࣛ࣋ࣜࣥࢢࢩࢫࢸ

᭱㧗 100 mm/s ࡲ࡛ࡢࢫ࢟ࣕࣥ㏿ᗘ࡟ࡍࢀࡤၥ㢟࡞࣒ࡀ⤌ࡳ㎸ࡲࢀ࡚࠸ࡿࠋࣛ࣋ࣜࣥࢢࡣ TPS ࡜୍⮴ࡉ࠸࡛࠶ࢁ࠺ࠋ

ࡏࡿࡇ࡜ࡀᮃࡲࡋ࠸ࠋ

III.B. ࢫ࢟ࣕࢽࣥࢢ⏝Ỉࢱࣥࢡ

III.B.2. ࢫ࢟ࣕࢼࡢ㥑ື

III.B.1. ࣏ࢪࢩࣙࢽࣥࢢ࡜ࣛ࣋ࣜࣥࢢ ᳨ฟჾࢆࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢᅄ㝮࡟ື࠿ࡋࠊ࡝

ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢ㐺ษ࡞タ⨨࡜ࣛ࣋ࣜࣥࢢ

ࡢⅬ࡛ࡶỈ㠃࡜᳨ฟჾࡢỈᖹࣞ࣋ࣝࡀ୍⮴ࡋ࡚࠸㸦㍈ྡࡢタᐃ㸧ࡣࠊ ᐃࢹ࣮ࢱࡢရ㉁ಖド࡜ࠊࢫ࢟ࡿࡇ࡜ࢆ☜ㄆࡍࡿᚲせࡀ࠶ࡿࠋࡶࡋࠊ᳨ฟჾࡢỈᖹࣕࣥࢹ࣮ࢱࡢ࢚࣮ࣛࡢཎᅉࢆ᳨ฟࡍࡿࡓࡵ࡟ࡣ୙

ࣞ࣋ࣝࢆ☜ㄆࡍࡿࡓࡵࡢ࢟ࣕࢵࣉᆺࡢᑓ⏝ჾලࢆྍḞ࡛࠶ࡿࠋࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢ㔜ࡳ࡛἞⒪ᐷྎ

ᡤ᭷ࡋ࡚࠸ࡿࡢ࡛࠶ࢀࡤ౑⏝ࡍ࡭ࡁ࡛࠶ࡿࠋࡲࡓࠊ

ࡢᨭᣢᶵᵓࡣ⡆༢࡟ቯࢀ࡚ࡋࡲ࠺ࡓࡵࠊỴࡋ࡚ᐷྎ᳨ฟჾୖࡢ࣐࣮ࢡࡸࡑࡢ௚ࡢ☜ㄆ⏝ჾලࢆ฼⏝ࡍ

32

III. スキャニングシステムのセットアップ

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)ࡿࡇ࡜࡛ࡶỈ㠃࡜ࡢ୍⮴ࢆ☜ㄆ࡛ࡁࡿࠋ
III.B.2.a. ࣅ࣮࣒୰ᚰ㍈ࡢࢫ࢟ࣕࢼࡢ㥑ືz ㍈᪉ྥࡢ᳨ฟჾࡣࠊ࢞ࣥࢺࣜゅᗘ 0 ᗘࡢ୰ᚰ㍈࡟ἢࡗ࡚ᖹ⾜࡟ື࠿࡞ࡅࢀࡤ࡞ࡽࡎࠊୗグࡢ᪉ἲ࡛☜ㄆࡍࡿࡇ࡜ࡀ࡛ࡁࡿࠋ
x㔜㗽࡟ἢࡗ࡚ᆶ┤᪉ྥ࡟࢔࣮࣒ࢆື࠿ࡋࠊṇ☜࡟ᆶ┤࡟⛣ືࡋ࡚࠸ࡿ࠿☜ㄆࡍࡿࠋx

jaw ࢆ᳨ฟჾࡢഃ㠃࠾ࡼࡧඛ➃࠿ࡽ 1 mm ⛬ᗘ

FIG. 6. Sequential appearance of chamber and its reflection in waterviewed from tank side. The correct position is when both images form
a perfect circle.

㛤ࡁࠊ᳨ฟჾࢆỈ㠃࠿ࡽᆶ┤࡟ỿࡵࠊ↷ᑕ㔝ෆࡢࢡࣟࢫ࣊࢔࡜᳨ฟჾࠊ࠾ࡼࡧග↷ᑕ㔝➃࡜᳨ฟჾࡢ఩⨨㛵ಀࢆぢࡿࡇ࡜࡛㍈ࢆ☜ㄆࡍࡿࠋࡶ

III.B.2.c. 㟁㞳⟽ࡢኚ఩Ỉ㠃࡜᳨ฟჾࡢ఩⨨ࢆṇ☜࡞SSD࡟ྜࢃࡏࡿࡇ࡜࡛ࠊ

ࡋ㍈ࡀࡎࢀ࡚࠸ࢀࡤ᫂ࡽ࠿࡟᳨ฟࡍࡿࡇ࡜ࡀ࡛

ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢཎⅬࢆタᐃࡍࡿࡇ࡜ࡀ࡛

ࡁࡿࠋࡁࡿࠋ࠸ࡃࡘ࠿ࡢ

ᐃࣉࣟࢺࢥ࡛ࣝࡣ᳨ฟჾࡢᗄఱ

ࡇࢀࡽࡢࢸࢫࢺࡣࠊࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢỈᖹㄪᩚᏛⓗ୰ᚰࡣ࡟ᙳ㡪ࡍࡿࡓࡵࠊỈࡣ‶ᮼࡢ≧ែ࡛⾜࠺࡭ࡁ࡛࠶ࡿࠋ

ᚰ࡟ኚ఩ࡍࡿᚲせࡀ࠶ࡿࠋගᏊ࡜㟁Ꮚ࡛ᐇຠ୰ᚰࡣ

ᐃⅬ࡛ࡣ࡞࠸ࡓࡵࠊ ᐃࡢ㝿ࡣᐇຠ୰␗࡞ࡾࠊࡉࡽ࡟ࣉࣟࢺࢥࣝ࡟ࡼࡗ࡚ࡶᐇຠ୰ᚰࡣ␗
III.B.2.b. ࢮࣟⅬࡢ῝ࡉ࡞ࡿヂ⪅ὀ 2 82,87,88ࠋ෇⟄ᙧ㟁㞳⟽ࢆỈࣇ࢓ࣥࢺ࣒୰࡛

SSD ࢆタᐃࡍࡿ㝿ࡣࠊ఩⨨Ỵࡵ࣮ࣞࢨࠊODIࠊ࣓౑⏝ࡍࡿሙྜࠊFig. 6 ࡟♧ࡍࡼ࠺࡟ᗄఱᏛⓗ୰ᚰࡣ࢝ࢽ࣏࢝ࣝ࢖ࣥࢱ࡞࡝࠿ࡽࠊᑡ࡞ࡃ࡜ࡶ஧ࡘࡢ᪉ἲ

ṇ☜࡟タ⨨ࡍࡿࡇ࡜ࡀ࡛ࡁࠊ㟁㞳⟽⥺㔞ィࡢࢩࣇࢺ࡟ࡼࡾ☜ㄆࡍ࡭ࡁ࡛࠶ࡿࠋ࣮ࣞࢨࡀ㊥㞳ィ࡜ࡋ࡚ᶵࡣࡇࡢึᮇ఩⨨࠿ࡽ⾜࠺ࡇ࡜ࡀ࡛ࡁࡿࠋከࡃࡢࢫ࢟

⬟ࡍࡿࡢ࡛࠶ࢀࡤ࡜࡚ࡶ⡆౽࡞᪉ἲ࡛࠶ࡿࡀࠊࡇࡢ

ࣕࢽࣥࢢࢩࢫࢸ࣒࡛ࡣࡇࡢ࢜ࣇࢭࢵࢺࢆࢯࣇࢺ࢘

᪉ἲࡢሙྜ࣮ࣞࢨࡢ఩⨨⢭ᗘࢆ☜ㄆࡋ࡚࠾ࡃᚲせ࢙࢔ୖ࡛ࠊࡶࡋࡃࡣᡭື࡛タᐃ࡛ࡁࡿࠋࡶࡋࢫ࢟ࣕ

ࡀ࠶ࡿࠋỈ㠃ࢆ࣮ࣞࢨ࠾ࡼࡧ࣓࢝ࢽ࣏࢝ࣝ࢖ࣥࢱࡢ

ࢽࣥࢢࢩࢫࢸ࣒ࡢࢯࣇࢺ࢙࢘࢔࡛࢜ࣇࢭࢵࢺࢆ⿵

఩⨨࡟ṇ☜࡟୍⮴ࡉࡏࠊ᳨ฟჾࡢ୰ᚰࢆỈ㠃࡟ࢭࢵṇࡍࡿ࡜ࠊ ᐃࡋࡓ್࡟㛵㐃ࡍࡿ῝ࡉࡣᩚᩘ࡛ࡣ࡞

ࢺࡍࡿࠋ෇⟄ᙧࡢ㟁㞳⟽ࡢሙྜࢭࢵࢺࡣᐜ࡛᫆ࠊୗ

ࡃ࡞ࡿࠋከࡃࡢ㟁㞳⟽ࡢ࢜ࣇࢭࢵࢺࡣ 1.5 mm࠿ࡽ࠿ࡽぢ࡚Ỉ㠃࡟཯ᑕࡋࡓ㟁㞳⟽ࡢᙧ≧࡛Ỵᐃ࡛ࡁ

2.0 mmࡢ㛫࡛ࠊࢮࣟⅬ࠿ࡽୗഃ࡟ࢩࣇࢺࡉࡏࡿࠋࡇ

ࡿࠋFig. 6 ࡢࡼ࠺࡟ࠊ
㸦Ỉ୰ࡢ㸧㟁㞳⟽࡜Ỉ㠃࡟཯ᑕࡢ᪉ἲ࡟ࡼࡾࠊṇ☜࡞῝ࡉ࡛ࡢᐃࡀྍ⬟࡜࡞ࡿࠋ

ࡋࡓീࡀࡁࢀ࠸࡞෇ࢆᥥ࠸࡚࠸ࢀࡤࠊ㟁㞳⟽୰ᚰ࡜Ỉ㠃ࡀṇ☜࡟୍⮴ࡋ࡚࠸ࡿࠋࡇࡢ࣏ࢪࢩࣙࣥࢆࢮࣟ

III.B.3. ࢫ࢟ࣕࢽࣥࢢࡢ᪉ྥ

Ⅼ࡜ࡋࠊࢫ࢟ࣕࣥ࡟౑⏝ࡍࡿ PC ࡟ᗙᶆࢆࢭࢵࢺࡍ

ከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣࢫ࢟ࣕࢽࣥࢢࢱ

࡭ࡁ࡛࠶ࡿࠋỈࡢ⵨Ⓨ࡟ࡼࡗ࡚Ỉ㠃ࡣኚ໬ࡍࡿྍ⬟ࣥࢡ࡜࢞ࣥࢺࣜࡢ㍈ࡢ㛵ಀࢆᐃ⩏ࡍࡿࡇ࡜ࡀ࡛ࡁ

ᛶࡀ࠶ࡿࡓࡵࠊ ᐃ᪥ࡢ᭱ึ࡜ࠊࡑࡢᚋᑡ࡞ࡃ࡜ࡶ

ࡿࠋ୍⯡ⓗ࡟ࡣ y ㍈ࡣ gun-target ᪉ྥ࡛ࠊx ㍈ࡣ

6 ᫬㛫࠾ࡁ࡟Ỉ㠃ࢆ☜ㄆࡍ࡭ࡁ࡛࠶ࡿࠋ࠶ࡿࢫ࢟ࣕ

cross-plane ᪉ྥ࡛࠶ࡿࡀࠊࡇࡢ఩⨨࡙ࡅ࡜ࢫ࢟ࣕࣥ

ࢽࣥࢢࢩࢫࢸ࣒ࡣࢫ࢟ࣕࣥ᫬࡟㸦᳨ฟჾ࠾ࡼࡧ㥑ື᪉ྥࡀṇࡋ࠸ࡇ࡜ࢆ☜ㄆࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋタ⨨࢔࣮࣒ࡀ㸧Ỉ࡟ỿࢇࡔศỈ㠃ࢆኚ᭦ࡍࡿ࣮ࣔࢱࢆᣢ

ࡍࡿ఩⨨㛵ಀ࡜ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡟ᐃ⩏ࡍࡿࡘࠋࢯࣇࢺ࢙࢘࢔ࡣỈࡢኚ఩࡟ᇶ࡙࠸࡚῝ࡉࢆኚ᭦఩⨨㛵ಀࡀṇࡋࡃ࡞࠸ሙྜࠊTPS ࡟ධຊࡍࡿࢹ࣮ࢱ

ࡍࡿࡀࠊࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡀ኱ࡁ࠸ሙྜࡣࡇࡢㄗ

ࢆㄗࡿྍ⬟ᛶࡀ࠶ࡿࠋ౛࠼ࡤࠊTPS ࡟ 45 ᗘࡢ࢙࢘ᕪࡣᑠࡉ࠸ࠋࡇࡢࡼ࠺࡞ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࢆ౑
⏝ࡍࡿሙྜࡣࠊ᧯సࡣ༑ศ࡟Ẽࢆࡘࡅࡿ࡭ࡁ࡛ࠊ౑
⏝๓࡟ࢯࣇࢺ࢙࢘࢔࡟ࡼࡿ⿵ṇࡀṇ☜࠿☜࠿ࡵ࡚࠾ࡃ࡭ࡁ࡛࠶ࡿࠋヂ⪅ὀ2ᶆ‽ ᐃἲ 01 ࠾ࡼࡧᶆ‽ィ ἲ 12 ࡟࠾࠸࡚ࡣࠊගᏊ⥺ࡢࡓࡵࡢኚ఩㔞ࡣ 0.6rcyl ࡛࠶ࡾࠊrcyl ࡣ㟁㞳✵Ὕࡢ༙ᚄࢆ♧ࡍࠋ

33

医学物理 第 33 巻 第 1 号

III. スキャニングシステムのセットアップ

FIG. 8. Effect of gantry angle tilt on the profiles of a 6 MV beam for
30×30 cm2 field at 10 cm depth.

࣮ࢱࡶṇ☜࡛ࡣ࡞ࡃ࡞ࡿࠋࡶࡋࠊFig. 7 ࡢࡼ࠺࡟ග
Ꮚ⥺ࡸ㟁Ꮚ⥺ࡢࣉࣟࣇ࢓࢖ࣝࡀ㐺ษ࡞ᙧ≧࡛࡞࠸ሙྜࡣࠊ࢔࣮࣒ࡸỈᵴࡀഴ࠸࡚࠸ࡿࡇ࡜ࡀ⪃࠼ࡽࢀࠊㄪᩚࢆ⾜࠺࡭ࡁ࡛࠶ࡿࠋ
III.B.3.b. ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢഴࡁ
FIG. 7. (a) Beam profiles of a 6 MV beam at different depth withࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢỈᖹᗘࡢㄪᩚࡣࢫ࢟ࣕ

scanning arm tilt for a 4×4 cm2 field, (b) electron beam profiles atࢽࣥࢢࢱࣥࢡ඲య࡛⾜࠺࠿ࠊ࢔࣮࣒ࡔࡅ࡛⾜࠺࠿ࡢ

depth of 80% depth dose for 20×20 cm2 cone with gantry tile. Arrows

2 ㏻ࡾ࠶ࡿࠋගᏊ⥺ࡢand circle are shown to represent the impact of arm and gantry tilt.

ᐃ࡟࠾࠸࡚ࠊ࢔࣮࣒ࡢഴࡁ

ࡀᑐ⛠ᛶ࡟୚࠼ࡿᙳ㡪ࡣᑠࡉ࠸ࠋࡋ࠿ࡋࠊFig. 7(a)࡟♧ࡍࡼ࠺࡟ࠊ࢔࣮࣒ࡀഴ࠸࡚࠸ࡿሙྜࠊಶࠎࡢࢫ
࢟ࣕࣥࡢ୰ᚰࡣ῝㒊࡟࡞ࡿ࡯࡝ࡎࢀࡿࠋᑠ↷ᑕ㔝ࡸࢵࢪࣉࣟࣇ࢓࢖ࣝࢆධຊࡍࡿ࡜ࡁ࡟ࠊᐇ㝿࡟ᐃࡋ࢙࢘ࢵࢪ↷ᑕ㔝࡛ࡇࡢᙳ㡪ࡣ㔜኱࡛ࠊPDD ࡣ୰ᚰ㍈ࡓࢹ࣮ࢱࡀ࢙࢘ࢵࢪࡢ㠀໙㓄᪉ྥ࡛࠶ࡿሙྜࡣࠊ῝࠿ࡽࡎࢀࠊ࢙࢘ࢵࢪࡢཌࡳࡀ␗࡞ࡿ㒊ศࢆ้࡞ࢹ࣮ࢱධຊ࣑ࢫ࡟ࡘ࡞ࡀࡿࠋ

ࡇ࡜࡟࡞ࡿࠋ㟁Ꮚ⥺࡛ࡣࠊFig. 7(b)ࡀ♧ࡍࡼ࠺࡟ࠊ

ᐃࡍࡿ≉࡟⥺㔞໙㓄ࡀᛴ࡞ప࢚ࢿࣝࢠ࣮ࡢሙྜࡣࠊdmax ௨
III.B.3.a. ࢫ࢟ࣕࣥ㍈ࡢ࢔ࣛ࢖࣓ࣥࢺ
ṇ☜࡞ࢹ࣮ࢱ

ᐃࢆ⾜࠺ࡓࡵ࡟ࡣࠊ࢞ࣥࢺࣜࡢ y㝆ࡢ῝ࡉ࡛࢔࣮࣒ࡢഴࡁ࡟ࡼࡿᙳ㡪ࡣ㢧ⴭ࡟⾲ࢀࡿࠋ᪉ྥ㸦in-plane㸧࡜ x ᪉ྥ㸦cross-plane㸧࡟ᑐࡋ࡚ࠊ
ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࢆṇ☜࡟ྜࢃࡏ࡞ࡅࢀࡤ࡞ࡽ
࡞࠸ࠋࡇࢀࡣࠊࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢഃ㠃࡟࠶ࡿ࣐

III.B.3.c. ࢞ࣥࢺࣜࡢഴࡁ
ࢫ࢟ࣕࣥ୰࡟࢞ࣥࢺࣜࡀഴ࠸࡚࠸ࡿሙྜࠊ

࣮ࢡ࡜࣮ࣞࢨࢆྜࢃࡏࡿ࠿ࠊ᳨ฟჾࡢಖᣢලࢆࣇ࢕

cross-plane ࡢࣉࣟࣇ࢓࢖ࣝࡸ PDD ࡟ᙳ㡪ࢆཬࡰࡍࠋ

࣮ࣝࢻࡢ➃࡟ྜࢃࡏࡿࡇ࡜࡛㐩ᡂࡉࢀࡿࠋࡇࢀࡣࡲ

ࡇࡢᙳ㡪ࡣᑠࡉ࠸ࡀࠊ῝㒊࡛ࣉࣟࣇ࢓࢖ࣝࡢ㠀ᑐ⛠ࡓࠊ㍈࡟ἢࡗ᳨࡚ฟჾࢆᡭື࡛⛣ືࡉࡏࡓ࡜ࡁ࡟ࠊ

ࡀ⏕ࡌࡿ㸦Fig. 8㸧ࠋࢫ࢟ࣕࣥ๓࡟࢞ࣥࢺࣜࢆỈᖹ࡟᳨ฟჾ୰ᚰࡀࢡࣟࢫ࣊࢔࡜࡝ࡢⅬ࡛ࡶ୍⮴ࡍࡿࡇࡍࡿࡇ࡜ࡣ୙ྍḞ࡛ࠊcross-plane ᪉ྥࡢ࡜ࢆಖドࡍࢀࡤ☜ㄆ࡛ࡁࡿࠋ఩⨨ྜࢃࡏࢆṇ☜࡟⾜⛠ࢆ㑊ࡅࡿࡓࡵࠊ࢞ࣥࢺࣜゅᗘࡣ⢭ᐦ࡞Ỉ‽ჾ࡛☜ࢃ࡞࠸࡜ࠊ ᐃࡋࡓࣉࣟࣇ࢓࢖ࣝࡢ↷ᑕ㔝ࢧ࢖ࢬࡣㄆࡍ࡭ࡁ࡛࠶ࡿࠋ

ṇ☜࡛ࡣ࡞ࡃ࡞ࡾࠊ࢙࢘ࢵࢪࣉࣟࣇ࢓࢖ࣝ࡞࡝ࡢࢹ

34

ᐃ࡛㠀ᑐ

III. スキャニングシステムのセットアップ

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)

III.C. ࢫ࢟ࣕࣥࡢ㥑ືᶵᵓ࡜ືࡁ

ࡍࡿ๓࡟ࡣࠊ஦๓࡟

III.C.1. 㓄ิᆺ᳨ฟჾࡢ㔜㔞ࡲࡓࠊ⿦⨨ࡢ⢭ᗘ⟶⌮ࡢࡓࡵࡢẖᖺࡢᰯṇࢆ⾜࠺๓Ỉࣇ࢓ࣥࢺ࣒ࢩࢫࢸ࣒࡟࠾࠸࡚ࠊ㸦᳨ฟჾࡢ㸧ಖ࡟ࡶࠊ஦๓ࡢ

ᐃࢸࢫࢺࢆ⾜࠺࡭ࡁ࡛࠶ࡿࠋ

ᐃࢸࢫࢺࡣ୙ྍḞ࡛࠶ࡿࠋࡍ࡭࡚ࡢ

ᣢල࡜ࢫ࢟ࣕࣥᶵᵓࡣẚ㍑ⓗᑠࡉࡃ㍍࠸᳨ฟჾࢆ

ࢣ࣮ࣈࣝࢆ᥋⥆ࡋ࡚ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡ࡟Ỉࢆ㈓᝿ᐃࡋ࡚సࡽࢀ࡚࠸ࡿࠋᗄࡘ࠿ࡢ㓄ิᆺࡢ᳨ฟჾࡣ

ࡵ࡞࠸≧ែ࡛ࠊࣇ࢕࣮ࣝࢻ⥺㔞ィࢆ࢔࢖ࢯࢭࣥࢱୖ

ಖᣢලࡢไ㝈ࢆ㉸࠼ࡓ㔜ࡉ࡛࠶ࡿࠋࢫ࢟ࣕࢽࣥࢢࢩ࡟タ⨨ࡋࠊࣜࣇ࢓ࣞࣥࢫ⥺㔞ィࡣࣇ࢕࣮ࣝࢻ⥺㔞ィࢫࢸ࣒࡛㓄ิᆺ᳨ฟჾࢆ౑⏝ࡍࡿ๓࡟ࠊ〇㐀ᴗ⪅࡟ࡢࢫ࢟ࣕࣥ⠊ᅖୖ࡟ධࡽ࡞࠸ࡼ࠺࡟㐺ษ࡟タ⨨ࡍ☜ㄆࢆ࡜ࡽࡡࡤ࡞ࡽ࡞࠸ࠋ㓄ิᆺ᳨ฟჾࡢ㔜ࡉ࡜ࢧࡿࠋࢫ࢟ࣕࣥ⏝ࡢ᳨ฟჾ࡟ࣅࣝࢻ࢔ࢵࣉ࢟ࣕࢵࣉࢆ

࢖ࢬࡢᙳ㡪ࢆ⪃៖ࡍࡿࡓࡵࠊࢹ࣮ࢱ཰㞟ࡢ๓࡟ࢫ࢟

⿦╔ࡋࠊ㟁఩ィ࡟ᚲせ࡞ㄪᩚࢆ⾜࠸ࠊ20 × 20 cm2 ࡢࣕࣥ࢔࣮࣒ࡢືࡁࢆ☜ㄆࡍࡿ࡭ࡁ࡛࠶ࡿࠋ

↷ᑕ㔝࡛ࠊ㸫20 ࠿ࡽ 20 cm ࡲ࡛✵୰࡛ࢫ࢟ࣕࣥࢆ⾜࠺ࠋࢫ࢟ࣕࢼ࡟ࡼࡗ࡚ࡣࠊࣜࣇ࢓ࣞࣥࢫ⥺㔞ィ࠿ࡽ

III.C.2. ㏿ᗘ࡜఩⨨ࡢ⢭ᗘಙྕࡀ࡞࠸ሙྜࠊࢫ࢟ࣕࣥࡀ೵Ṇࡍࡿࡓࡵࢻࣛ࢖ࣛ

᳨ฟჾࡢಙྕࡢᙉᗘࠊឤᗘࠊ㟁఩ィࡢ཰㞟᫬㛫ࠊࣥࢆ⾜࠼࡞࠸ࢱ࢖ࣉࡶ࠶ࡿࠋ

఩⨨⢭ᗘ࡟ࡼࡗ࡚ࡣ᳨ฟჾࡢ⛣ື㏿ᗘ࡟ࢫ࢟ࣕࢽ

ᐃࢆ⧞ࡾ㏉ࡋ⾜࠸ࠊ᳨ฟჾࡀࢡࣟࢫ࣊࢔୰ᚰ࡟

ࣥࢢࢩࢫࢸ࣒ࡀᑐᛂ࡛ࡁ࡞࠸ሙྜࡀ࠶ࡿࠋࡇࢀࡽࢆ

㐩ࡋࡓࡽ↷ᑕࢆ୰᩿ࡍࡿࠋࢫ࢟ࣕࣥࢹ࣮ࢱࢆಖᏑࡋ

☜ㄆࡍࡿࡓࡵ࡟ࠊ᭱㧗㏿ᗘ࡜᭱ప㏿ᗘ࡟࠾࠸࡚ࠊ20࡚ࠊࢫ࢟ࣕࢼࡢࢯࣇࢺ࢙࢘࢔ࡸࢫࣉࣞࢵࢻࢩ࣮ࢺࢆ

cm ࡢ↷ᑕ㔝࡛ 40 cm ࡢ⠊ᅖࢆࢫ࢟ࣕࣥࡋࠊ஧ࡘࡢ

౑⏝ࡋ࡚ࠊḟࡢ㡯┠ࢆゎᯒࠊ᳨ウࢆ⾜࠺ࠋࣉࣟࣇ࢓࢖ࣝࢆẚ㍑ࡍ࡭ࡁ࡛࠶ࡿࠋࡶࡋ┦ᑐⓗ࡞ᙧxࣀ࢖ࢬ㸸ࣉࣟࣇ࢓࢖ࣝࡢᖹᆠ࡞㒊ศࡢᶆ‽೫ᕪ≧ࡣ୍⮴ࡋ࡚࠸࡚ࠊ఩⨨ࡀࢩࣇࢺࡋ࡚࠸ࢀࡤࠊࢫ࢟

ࢆồࡵࡿࠋࡇࢀࡣ↷ᑕ᫬ࡢࣀ࢖ࢬࡢᶆ‽೫ᕪࢆ

ࣕࣥ㏿ᗘ࡟㝈⏺ࡀ࠶ࡿࡇ࡜ࡀ☜ㄆ࡛ࡁࡿࠋ

♧ࡋ࡚࠸ࡿࠋ
x

III.C.3. ࣄࢫࢸࣜࢩࢫ

SN ẚ㸸ྠࡌ㡿ᇦ࡛ࠊᶆ‽೫ᕪ࡜ᖹᆒ್ࡢẚ㸦ኚືಀᩘ㸧ࡢィ⟬ࢆ⾜࠺ࠋࡇࡢ್ࡣ SN ẚ࡟㏆࠸ࢫ࢟ࣕࢼࡢ఩⨨ࡢ࢚ࣥࢥ࣮ࢹ࢕ࣥࢢ࡟࠾࠸࡚ࣄ
ࢫࢸࣜࢩࢫࡀ㉳ࡁ࡚࠸࡞࠸࠿☜ㄆࡍ࡭ࡁ࡛࠶ࡿࠋࣄ

್࡜࡞ࡿࠋ
x

᫬ᐃᩘ㸸↷ᑕࢆṆࡵࡓ᫬Ⅼ࠿ࡽ᳨ฟჾࡢಙྕࡀ

ࢫࢸࣜࢩࢫ⌧㇟ࡣ୍⯡ⓗ࡟ᪧᆺࡢࢫ࢟ࣕࢽࣥࢢࢩ

࡞ࡃ࡞ࡿࡲ࡛ࡢ᫬㛫ࢆࢫࢸ࣒࡛ၥ㢟࡟࡞ࡾࠊࡇࡢ⌧㇟ࡣྠࡌ↷ᑕ㔝࡛ࠊ୰ჾ࡟ṧࡿ㟁Ⲵࡶྵࡵࡓࠊ᫬ᐃᩘࡶࡋࡃࡣᛂ⟅᫬⛬ᗘࡢࢫࣆ࣮ࢻ࡛ ᚟ࡋ࡚ࢫ࢟ࣕࣥࢆ⾜࠺ࡇ࡜࡛㛫࡜㛵ಀࡋ࡚࠸ࡿࠋ

☜ㄆ࡛ࡁࡿࠋࡶࡋࠊ஧ࡘࡢࣉࣟࣇ࢓࢖ࣝࡀ᏶඲࡟୍

xᐃࡍࡿࠋࡇࢀࡣࠊ᳨ฟ

₃ࢀ㟁ὶ㸸↷ᑕࢆ⾜ࡗ࡚࠸࡞࠸࡜ࡁࡢ್ࡀⴠࡕ

⮴ࡋ࡚࠸࡞࠸ሙྜࠊࢫ࢟ࣕࣥࡢືస࡟ࣄࢫࢸࣜࢩࢫ

╔࠸࡚ᖹᆠ࡟࡞ࡗࡓ㡿ᇦࡢࠊᖹᆒ್࡜ᶆ‽೫ᕪࡀ㉳ࡁ࡚࠸ࡿࡇ࡜࡟࡞ࡿࠋࡇࡢࡼ࠺࡞⌧㇟ࡀⓎ⏕ࡋࢆồࡵࡿࠋࡓሙྜࡣ〇㐀ᴗ⪅࡟ಟ⌮ࢆ౫㢗ࡋࠊࢫ࢟ࣕࢽࣥࢢ

xᐃ࡟౑⏝ࡍ࡭ࡁ࡛ࡣ࡞࠸ࠋ

㟁఩ィ࢜ࣇࢭࢵࢺ㸸ࡶࡋࠊ㟁఩ィ࡟ࢤ࢖ࣥࡢ⮬ືㄪᩚᶵ⬟ࡀ࡞࠸ࡢ࡛࠶ࢀࡤࠊ↷ᑕࢆ⾜ࡗ࡚࠸࡞࠸㒊ศࡢᶆ‽೫ᕪ࡜ࠊᖹᆠ࡟↷ᑕࡉࢀ࡚࠸ࡿ

III.C.4. ⭉㣗㸦ࡉࡧ㸧㒊ศࡢᶆ‽೫ᕪࡣ࡯ࡰྠ➼࡟࡞ࡿ࡭ࡁ࡛࠶ࡿࠋ

Ỉ࡬ࡢῧຍ≀ࡸಖᏑ᪉ἲ࡞࡝࡟ࡘ࠸࡚ࡣᴗ⪅ࡢ↷ᑕࡋ࡚࠸࡞࠸ሙྜࡢ್ࡢᖹᆒ್ࡣ㟁఩ィࡢ࢜ᥦ᱌࡟ᚑ࠺࡭ࡁ࡛࠶ࡿࠋ㛗ᮇ࡟ࢃࡓࡾ౑⏝ࡋ࡞࠸ሙࣇࢭࢵࢺ࡛ࠊྠࡌࢤ࢖ࣥ࡟࠾ࡅࡿ

ྜࠊ≉࡟᪥ࢆࡲࡓࡄࡼ࠺࡞ሙྜࡣࠊࢫ࢟ࣕࣥᶵᵓࢆ

࡚ࡢࢹ࣮ࢱ࠿ࡽῶ⟬ࡍ࡭ࡁ࡛࠶ࡿࠋ
xỈ࡟ᾐࡋ࡚࠾ࡃ࡭ࡁ࡛ࡣ࡞࠸ࠋ

ᐃ࡛ࡣࡍ࡭㸦ಙྕࡀ㸧㈇ᴟᛶ㸸ࡶࡋ㟁఩ィࡀ 2 ᴟ࡛࠶ࢀࡤࠊ
ࡢ್ࢆ࡜ࡿࡇ࡜ࡶ࠶ࡾࠊᖹᆒ್ࡀ㈇࡟࡞ࡿࡇ࡜

III.D.

ᐃ๓ࡢヨ㦂ࡶ࠶ࡿࠋ㸦࢜ࣇࢭࢵࢺࢆᕪࡋᘬࡃሙྜ࡞࡝࡟㸧㈇III.D.1. ࢻࣛ࢖ࣛࣥ

ࡢᖹᆒ್ࢆῶ⟬ࡍࡿሙྜࡣࠊ⤖ᯝ࡜ࡋ࡚ṇࡢ್᪂ࡋ࠸ࢫ࢟ࣕࢼࢆ౑⏝ࡋ࡚ࣅ࣮࣒ࢹ࣮ࢱࢆ

ᐃࢆຍ⟬ࡍࡿࡇ࡜࡟࡞ࡿࡢ࡛ࠊṇ㈇ࡢ➢ྕࡣṧࡋ

35

医学物理 第 33 巻 第 1 号

xIII. スキャニングシステムのセットアップ࡚࠾ࡃ࡭ࡁ࡛࠶ࡿࠋ

ࡀ᭷ព࡛࠶ࡿ࠿ࠊࣉࣟࣇ࢓࢖ࣝࡢࢸ࣮ࣝ㒊ศࡢ↓ຠ࡞್㸸↷ᑕࢆ⾜ࡗ࡚࠸࡞࠸᫬ࡢ್㸦ࣂࢵࢡ್ࢆẚ㍑ࡍࡿࡇ࡜࡛☜ㄆࡋ࡞ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋ

ᐃࢢࣛ࢘ࣥࢻ㸧ࡀᖖ࡟ 0 ࡛ኚືࡀ࡞࠸ሙྜࠊࢹ࣮
ࢱࡀᙉไⓗ࡟ 0 ࡟⿵ṇࡉࢀ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿࠋ
ࡇࢀ࡟ࡼࡾࠊ༙ᙳ㒊ศࡸࢸ࣮ࣝࡢ㒊ศ࡟ᐃㄗ

III.D.5. ࢚ࢿࣝࢠ࣮ᛂ⟅ᛶࡢヨ㦂ࢲ࢖࣮࢜ࢻ᳨ฟჾ࡛ PDD ࢆᐃࡍࡿሙྜࠊ࢚ࢿ

ࣝࢠ࣮ᛂ⟅ࡣ 6 MV ࡢගᏊ⥺ࡢ኱↷ᑕ㔝㸦40 × 40ᕪࡀ㉳ࡁࡿྍ⬟ᛶࡀ࠶ࡿࠋ

cm2㸧࡟࠾ࡅࡿ኱ࡁ࡞య✚ࡢ㟁㞳⟽࡛
III.D.2. ࢛࣮࢘ࢱࣛࣥ

ᐃࡋࡓ PDD࡜ẚ㍑ࡍࡿࡇ࡜࡛ࠊホ౯ࡍࡿࡇ࡜ࡀ࡛ࡁࡿࠋdmax ௨᳨ฟჾ࡜ࢣ࣮ࣈࣝࡀᾐỈࡋࡓ≧ែ࡛ࠊࢣ࣮ࣈࣝࡢ㝆ࡢ῝ࡉࡢ PDD ࡟࠾࠸࡚ࠊ㟁㞳⟽⥺㔞ィ࡟ẚ࡭ࢲࢪࣕࢣࢵࢺࡢட⿣ࡸ₃㟁ࡀ㉳ࡁ࡚࠸ࡿሙྜࠊ ᐃᶵ࢖࣮࢜ࢻ᳨ฟჾࡢ⥺㔞᭤⥺ࡢῶᙅࡍࡿഴࡁࡀᑠࡉჾࡢᅇ㊰ࡢࣃ࣓࣮ࣛࢱࡀኚ໬ࡋࠊ ᐃ⤖ᯝࡶኚ໬ࡍ

࠸ሙྜࠊࡇࢀࡣ࢚ࢿࣝࢠ࣮ᛂ⟅ࡢ㐪࠸ࢆ♧ࡋ࡚࠸ࡿࠋ

ࡿྍ⬟ᛶࡀ࠶ࡿࠋࡶࡋࢥࢿࢡࢱࡀ㜵ᾐᆺ࡛࡞࠸ࡢ࡛

ࡇࡇ࡛౑⏝ࡍࡿ኱ࡁ࠸ࢧ࢖ࢬࡢ㟁㞳⟽⥺㔞ィ㸦౛࠼࠶ࢀࡤࠊỈ࡟ỿࡵ࡚ࡣ࡞ࡽ࡞࠸ࠋࢫ࢟ࣕࢽࣥࢢࢱࣥ

ࡤ 0.6 cm3㸧ࡣࠊ௚ࡢࡍ࡭࡚ࡢヨ㦂࡟ྜ᱁ࡋ࡚࠾ࡾࠊ

ࢡ࡟Ỉࢆ㈓ࡵࠊ᳨ฟჾ࡜ࢣ࣮ࣈࣝࢆỈ࡟ỿࡵࡓᚋࠊ

ࢫࢸ࣒ࡢ₃ࢀ㟁ὶࡢᙳ㡪࡞࡝ࢆཷࡅ࡞࠸ࡇ࡜ࡀ๓

☜ㄆࢆ⾜࠺ࡲ࡛࡟ 30 ศ࠿ࡑࢀ௨ୖ⤒ࡗ࡚࠿ࡽ⾜࠺ᥦ࡛࠶ࡿࠋࡢࡀ᭱㐺࡛࠶ࡿࠋࢻࣛ࢖ࣛࣥ࡜ྠࡌࢸࢫࢺࢆ⧞ࡾ㏉ࡋࠊࡑࢀࡽࡢࣃ࣓࣮ࣛࢱࡀ࡯ࡰ୍⮴ࡋ࡚࠸ࡿࡇ࡜ࢆ
☜ㄆࡍࡿࠋࣀ࢖ࢬࡢᶆ‽೫ᕪࡀቑຍࡋࡓሙྜࠊࢫ࢟

III.E. ࢹ࣮ࢱྲྀᚓ
ࢹ࣮ࢱ཰㞟ࡣΰ஘ࢆ㑊ࡅࡿࡓࡵ࡟ࠊ⣔⤫❧࡚࡚⾜ᐃࡀ෌ᗘᚲせ࡜࡞ࡿࠋࡇࡢ

࠺࡭ࡁ࡛࠶ࡿࠋከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡟࠾࠸

ᐃ್ࡢ SN ẚࡣ᭱ࡶపࡃ࡞ࡿࡣࡎ࡛࠶ࡿࡀࠊࡇࡢ

࡚ࢹ࣮ࢱ཰㞟ࡢᡭ㡰ࢆᩚ࠼ࡿࡇ࡜ࡣࠊࡢࡕࡢࢹ࣮ࢱ

SN ẚࡣ᪤▱ࡢࢩࢫࢸ࣒ࡢឤᗘ࠿ࡑࢀ௨ୖ࡛࠶ࡿ࡭

ゎᯒࡢຠ⋡ࢆ኱ᖜ࡟ྥୖࡉࡏࡿࠋࡲࡓࠊࢹ࣮ࢱࡢ୍ࡁ࡛࠶ࡿࠋ㈏ᛶ࡜ṇ☜ࡉࢆྥୖࡉࡏࡿࡓࡵ࡟ࠊྠࡌࢭࢵࢺ࢔ࢵ

ࣕࣥྍ⬟࡞᭱኱῝࡛ࡢࣉ࡛ྲྀᚓ࡛ࡁࡿࢹ࣮ࢱࡣྠ᫬࡟཰㞟ࡍࡿ࡭ࡁ࡛࠶
III.D.3. 㣬࿴ヨ㦂

ࡿࠋTable I ࡢࡼ࠺࡞ࢫࣉࣞࢵࢻࢩ࣮ࢺࢆ⏝࠸࡚ ୖグࡢࢻࣛ࢖ࣛࣥ࡜ྠࡌᡭ㡰࡛ࠊ⥺㔞⋡ࢆ᭱኱࡜2

୰⛬ᗘ࡟タᐃࡋ࡚ 20 × 20 cm ࡢ↷ᑕ㔝ࡢᐃࢆ⾜ᐃ㡯┠ࢆᩚ⌮ࡍࡿࡇ࡜࡛ࠊࢹ࣮ࢱ཰㞟ࢆࡍࡤࡸࡃฎ⌮࡛ࡁࡿࠋ࠸ࠊࣉࣟࣇ࢓࢖ࣝࡢẚ㍑ࢆ⾜࠺ࠋ
III.E.1. ࢫ࢟ࣕࣥࣃ࣓࣮ࣛࢱࡢࣉࣟࢺࢥࣝ
III.D.4. 㟁㞳య✚እຠᯝࢹ࣮ࢱ཰㞟࡟ࡣࠊ౑⏝ࡍࡿࢯࣇࢺ࢙࢘࢔࡟౫Ꮡࡍ

ࢫ࢟ࣕࣥ⏝ࡢ㟁㞳⟽⥺㔞ィࡢ㟁㞳య✚ࡣ㠀ᖖ࡟ࡿᗄࡘ࠿ࡢせ⣲ࡀ࠶ࡿࠋࢹ࣮ࢱࡢ㉁ࡣࠊࢫ࢟ࣕࣥ㏿ᑠࡉ࠸ࡓࡵࠊࢣ࣮ࣈࣝࡸࢥࢿࢡࢱ࡞࡝ࡢ㟁㞳య✚௨ᗘࠊ㐜ᘏ᫬㛫ࠊࢧࣥࣉࣜࣥࢢ᫬㛫࡟౫Ꮡࡍࡿࡓࡵࠊ

እࡢ㒊ศ㸦Extracameral volume㸧࡟ᩓ஘⥺ࡸ୍ḟ⥺ࢯࣇࢺ࢙࢘࢔ࡢ≉ᚩࢆά⏝ࡋ࡚᭱㐺࡞ࢹ࣮ࢱ཰㞟ࡀ↷ᑕࡉࢀࡿ࡜ࠊ㟁㞳ࡀ㉳ࡁ࡚ࢆࡍ࡭ࡁ࡛࠶ࡿࠋSec. I B 4 ࡛㏙࡭ࡓࡼ࠺࡟ࠊࣅ࣮࣒

ᐃಙྕ࡟ᙳ㡪ࢆཬࡰࡍ㸦㟁㞳య✚እຠᯝ㸸Extracameral effect㸧

83,84,89ࠋࢥ࣑ࢵࢩࣙࢽࣥࢢ࡟ࡣከࡃࡢ᫬㛫ࡀᚲせ࡜࡞ࡿࠋᘧ

Extracameral volume ࡣࠊ཰㞟ຠ⋡ࡢ㧗࠸㟁㞳✵Ὕෆ(1)࡛♧ࡍࡼ࠺࡟ࠊࢫ࢟ࣕࣥ㏿ᗘࢆୖࡆࠊࢧࣥࣉࣜࣥ

㒊࠿ࡽ⏕ࡌࡿࡢ࡛ࡣ࡞࠸ࡓࡵࠊ୍ᐃ࡛ࡣ࡞࠸ࠋ㣬࿴ࢢ᫬㛫ࢆ▷ࡃࡋ࡚⢒࠸཰㞟ࢆ⾜࠺࡜඲యࡢࢫ࢟ࣕ

ࢸࢫࢺ⤊஢ᚋ࡟᳨ฟჾࢆ࣐࢘ࣥࢺ࠿ࡽእࡋ࡚㟁఩ࣥ᫬㛫ࡣῶࡿࡀࠊప࢚ࢿࣝࢠ࣮㟁Ꮚ⥺࡛ࡣࢫ࢟ࣕࣥ

ィࡢ㏆ࡃ࡟࠾ࡁࠊ᭱኱⥺㔞⋡࡛↷ᑕࡋࡓሙྜ࡜↷ᑕ㏿ᗘࢆୖࡆ࡚ࢧࣥࣉࣜࣥࢢ᫬㛫ࢆῶࡽࡍ࡜᭱㐺࡞ࢆ⾜ࢃ࡞࠸ሙྜࡢ᳨ฟჾࡢᛂ⟅ࢆグ㘓ࡍࡿࠋ᳨ฟჾ

ࢹ࣮ࢱࡣᚓࡽࢀ࡞࠸ࠋࡇࢀࡽࡢヲ⣽ࡣྛࢭࢡࢩࣙࣥ

ࡢ཯ᛂࡀኚ໬ࡋࡓሙྜࠊࡑࢀࡣ Extracameral volume

࡛㏙࡭ࡿࠋ࡟ࡼࡿᙳ㡪࡛࠶ࡿࠋࡇࢀࡣࠊ᳨ฟయ✚ࡀ Extracameralvolume ࡟ẚ࡭ᑠࡉ࠸ࡓࡵࡔ࡜⪃࠼ࡽࢀࡿࠋࡇࡢຠᯝ

36

III.E.2. ࢫ࢟ࣕࣥ㏿ᗘIII. スキャニングシステムのセットアップ

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)

ࢫ࢟ࣕࣥ㏿ᗘࢆ㏿ࡃࡍࡿ࡜ࣀ࢖ࢬࡣቑຍࡋࠊࡲࡓࠊ
࢔࣮࣒ࡢືࡁ࡟ࡼࡾἼࡀ❧ࡘࡇ࡜࡛ᐃ್ࡶἼᡴࡘࠋࡇࢀࡣࠊప࢚ࢿࣝࢠ࣮㟁Ꮚ⥺࡟࠾࠸࡚ dmax ௨ୖࡢ῝ࡉࡢࣉࣟࣇ࢓࢖ࣝࢆ

ᐃࡍࡿ㝿࡟኱ࡁ࡞ᙳ㡪ࢆཬࡰࡍࠋ࢔࣮࣒ࡀ㏿ࡃືࡁࡍࡂࡿ࡜Ỉ㠃ࡀἼ❧ࡕୖୗࡍࡿࡓࡵࠊ ᐃ῝࡟ᙳ㡪ࢆ୚࠼ࡿࠋࡇࡢᙳ㡪ࡣ
Fig. 9 ࡛♧ࡉࢀ࡚࠾ࡾࠊPDD ࡛ࡶྠࡌࡼ࠺࡟Ἴᡴࡗ
ࡓ᭤⥺ࡀほᐹࡉࢀࡿࠋࢫ࢟ࣕࣥ㏿ᗘࡣࠊᑠࡉ࡞㟁㞳య✚ࡢ㟁㞳⟽ࢆ౑⏝ࡋࡓᑠ↷ᑕ㔝ࡢᐃ࡟ࡶ㔜኱࡞ᙳ㡪ࢆ୚࠼ࡿࠋ㟁㞳య✚ࡀᑠࡉ࡞㟁㞳⟽ࡢሙྜࡣಙྕࡀᑠࡉ࠸ࡓࡵࠊࢫ࢟ࣕࣥ㏿ᗘࢆ㐜ࡃࡍࡿࡇ࡜࡛

FIG. 9. Impact of scanning speed on the quality of electron profile.

ಙྕ㔞ࢆቑࡸࡋࠊ⤫ィⓗኚືࢆῶࡽࡍᚲせࡀ࠶ࡿࠋIII.E.3. 㐜ᘏ᫬㛫㐜ᘏ᫬㛫࡜ࡣ㞄ࡾྜ࠺

III.F. ࢹ࣮ࢱࣇ࢓࢖ࣝ
ᐃⅬ㛫ࢆ⛣ືࡍࡿ᫬㛫ࢆᣦࡍࠋ㛗࠸㐜ᘏ᫬㛫ࢆ࡜ࡿࡇ࡜࡛
࡞ࡿࡀࠊప࢚ࢿࣝࢠ࣮㟁Ꮚ⥺ࡢᐃ᫬㛫ࡣ㛗ࡃ

ᐃࡢࡼ࠺࡟ᑠࡉ࡞

III.F.1. ࢹ࣮ࢱࣇ࢓࢖ࣝࡢᵓᡂ
ࢹ࣮ࢱ᳨⣴ࢆ⡆౽࡟ࡍࡿࡓࡵ࡟ࠊගᏊ⥺ࡢࢹ࣮ࢱ࡜㟁Ꮚ⥺ࡢࢹ࣮ࢱࡣ␗࡞ࡿྡ๓ࡢࣇ࢛ࣝࢲ࡟ศࡅ

ࡉࡊἼࡢᙳ㡪ࢆ኱ࡁࡃཷࡅࡿሙྜ࡟ࡣࠊࡑࢀࡽࡢᙳ

࡚ಖᏑࡍ࡭ࡁ࡛࠶ࡿࠋࡉࡽ࡟ࠊගᏊ⥺ࡢࣇ࢛ࣝࢲࡢ

㡪ࡢపῶ࡟᭷ຠ࡛࠶ࡿࠋ

୰࡛ࡶ࣮࢜ࣉࣥࡸ࢙࢘ࢵࢪ࡞࡝ࡢྡ๓ࡢࣇ࢛ࣝࢲ
ࢆసࡿࡇ࡜࡛ࠊ⣽ศ໬ࡍࡿࡇ࡜ࡀ࡛ࡁࡿࠋඃࢀࡓࣇ

III.E.4. ࢧࣥࣉࣜࣥࢢ᫬㛫࡜ಙྕࢧࣥࣉࣜࣥࢢ᫬㛫࡜ࡣࠊ᳨ฟჾࡀࢹ࣮ࢱ཰㞟ࡢࡓࡵ࡟೵Ṇࡋ࡚࠸ࡿ᫬㛫ࢆᣦࡍࠋࢧࣥࣉࣜࣥࢢ᫬㛫ࡣࠊ࢓࢖ࣝࡢᵓᡂࢆ⤌ࡳୖࡆࡿࡇ࡜࡛ࠊከࡃࡢࢹ࣮ࢱࡢ
୰࠿ࡽ≉ᐃࡢࢹ࣮ࢱࢆ᥈ࡋฟࡍసᴗ᫬㛫ࢆ኱ᖜ࡟ᢚ࠼ࡿࡇ࡜ࡀ࡛ࡁࡿࠋ

㟁఩ィࡢࢤ࢖ࣥࡸ᳨ฟჾࡢࢧ࢖ࢬ㸦ಙྕࡢ㔞㸧࡟ࡼࡗ࡚ㄪᩚࡍࡿ࡭ࡁ࡛࠶ࡿࠋࡲࡓࠊࢹ࣮ࢱ཰㞟ࢆ⾜࠺III.F.2. ࣇ࢓࢖ࣝࡢྡ๓๓࡟ࠊ ᐃࢆ⾜࠺᭱኱῝ᗘࡢ༙ᙳ㡿ᇦ࡟࡚ಙྕࡢ㔞ࢹ࣮ࢱࢆ཰㞟ࡍࡿ㝿࡟ࠊࡢࡕࡢࢹ࣮ࢱ᳨⣴ࢆ⡆౽ࢆ☜ㄆࡋࠊ㐺ษ࡞ࢧࣥࣉࣜࣥࢢ᫬㛫ࢆỴᐃࡍ࡭ࡁ࡛

࡟ࡍࡿࡓࡵ࡟ࠊࣇ࢓࢖ࣝྡࡢỴᐃἲࢆ☜❧ࡋ࡚࠾ࡃ࠶ࡿࠋࡲࡓࠊ๭ࡾᙜ࡚ࡽࢀࡓࢥ࣑ࢵࢩࣙࢽࣥࢢ᫬㛫࡭ࡁ࡛࠶ࡿࠋከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡛ࡣࠊ⮬ࢆ㉸࠼࡞࠸ࡼ࠺࡞ࢧࣥࣉࣜࣥࢢ᫬㛫ࢆタᐃࡍࡿࡇືⓗ࡟ࣇ࢓࢖ࣝࡢྡ๓ࡀ๭ࡾᙜ࡚ࡽࢀࡿ࠿ 8 ᩥᏐ௨

࡜ࡶᚲせ࡛࠶ࡿࠋ

ෆࡲ࡛࡜㝈ᐃࡉࢀ࡚࠾ࡾࠊࡇࢀࡽࡣྡ๓ࡢỴᐃἲࢆ」㞧࡟ࡍࡿࠋࡶࡋࣇ࢓࢖ࣝྡࡢᩥᏐᩘࡀ 8 ᩥᏐ௨ෆIII.E.5. 㧗࿘Ἴࣀ࢖ࢬࡢᖸ΅࡟㝈ᐃࡉࢀ࡚ࡋࡲ࠺ሙྜࠊΰ஘ࡋ࡞࠸ࡼ࠺࡞ྡ๓ࢆ

ᐃࢩࢫࢸ࣒඲యࡢఏᑟᛶ㐽ⶸయ㸦㟁㞳⟽ࡸࢲ࢖ࡘࡅࡿࡇ࡜ࡸࠊ㔜」ࡋ࡞࠸ྡ๓ࢆ௜ࡅࡿࡓࡵࡢᕤኵ

࣮࢜ࢻࡢࢩ࢙ࣝࠊࢣ࣮ࣈࣝࡢࢩ࣮ࣝࢻࠊࢥࢿࢡࢱ࢔ࡀᚲせ࡜࡞ࡿࠋࣇ࢓࢖ࣝྡࡢỴᐃἲࡢ౛࡜ࡋ࡚ࠊ࢚

ࢲࣉࢱࠊ㟁఩ィࡢࢥࢿࢡࢱࠊ㟁఩ィࡢ⟂య㸧ࡀṇᖖࢿࣝࢠ࣮࣭࣮࢜ࣉࣥࡲࡓࡣ࢙࢘ࢵࢪ࣭ࢫ࢟ࣕࣥ᪉ἲ

࡛࠶ࢀࡤࠊ᳨ฟჾࡢಙྕ࡟ᑐࡋ࡚㧗࿘Ἴ࡟ࡼࡿᖸ΅ࡢࡼ࠺࡟༊ศࡅࡍࡿ㸦౛㸸6P15WDD㸧ࠋࡓ࡜࠼ࡣ࡞࠸ࠋ༢⣧࡞ఏᑟᛶ㐽ⶸయࡢࢸࢫࢺࡣࠊ஝⇱ࡋࡓ

Windows ࡢࣇ࢓࢖ࣝྡไ㝈ࡢࡳ࡛࠶ࡗࡓ࡜ࡋ࡚ࡶࠊ

㒊ᒇࡢ୰࡛ࣇࣟ࢔࡟㠐ࢆࡘࡅ࡚ᘬࡁࡎࡾ࡞ࡀࡽṌ

ࠕ6 MV open depth dose setࠖࡸࠕ18 MV 15 deg wedgeࡃࠊ ᐃࢩࢫࢸ࣒ࡢୖ࡛ᡭࢆ᣺ࡿ࡞࡝ࡢ⾜Ⅽࢆ⾜࠸ࠊ

10×10 profilesࠖࡢࡼ࠺࡟ࠊࡢࡕ࡟᳨⣴ࡍࡿ㝿࡟ΰ஘㟼㟁ẼࢆⓎ⏕ࡉࡏࡿࡇ࡜࡛⾜࠺ࡇ࡜ࡀ࡛ࡁࡿࠋࡉࡽ

ࡋ࡞࠸ࡼ࠺࡞ࣇ࢓࢖ࣝྡࡢỴᐃἲࢆ᥇⏝ࡍ࡭ࡁ࡛࡟ࠊ㒊ရ࡟ゐࢀࡓሙྜࡢ

࠶ࡿࠋ࠸ࡃࡘ࠿ࡢᪧᘧࡢࢩࢫࢸ࣒࡛ࡣࠊࣇ࢓࢖ࣝࡣ

ᐃᛂ⟅ࡢኚ໬ࢆ☜ㄆࡍࡿࡇ࡜࡛ࠊ᥋⥆ࡢၥ㢟ࢆ᫂ࡽ࠿࡟ࡍࡿࡇ࡜ࡀ࡛ࡁࡿࠋ

ࢩࣥࢢࣝࣇ࢓࢖ࣝ࡜ࡋ࡚ෆ㒊࡟ಖᏑࡉࢀࡿࡶࡢࡶ

37

医学物理 第 33 巻 第 1 号

IV. 光子線のビームデータ࠶ࡿࠋࡇࡢࡼ࠺࡞ሙྜ࡛ࡣࠊࡢࡕ࡟᳨⣴ࡸゎᯒ࡟ᙺ

TPS࡛ࡣSSDࢆ 90 cm࡜ࡋ࡚ࢥ࣑ࢵࢩࣙࢽࣥࢢࢆ⾜❧ࡘࡼ࠺࡟ࠊಶࠎࡢࢫ࢟ࣕࣥࢹ࣮ࢱࢆಖᏑࡍࡿ㝿࡟࠺ࠋࡋ࠿ࡋࠊTPS࣋ࣥࢲ࣮ࡣ័⩦ⓗ࡟SSD=100 cmࢆ

ヲ⣽࡞ࢥ࣓ࣥࢺࢆグධࡍࡿ࡭ࡁ࡛࠶ࡿࠋ

ᣦᐃࡍࡿሙྜࡀ࠶ࡿࠋࡉࡽ࡟ࠊ⌧ᅾࡢ୍㒊ࡢ⥺㔞ᰯṇࣉࣟࢺࢥࣝヂ⪅ὀ 3࡛ࡣࠊSSD=100 cmࡢPDDࡀᚲせIV. ගᏊ⥺ࡢࣅ࣮࣒ࢹ࣮ࢱ

࡛࠶ࡿࠋࡼࡗ࡚ࠊࣅ࣮࣒ࢥ࣑ࢵࢩࣙࢽࣥࢢࡢ 1 ࡘ࡜

IV.A. ගᏊ⥺ࢫ࢟ࣕࣥࢹ࣮ࢱ
ᚲせ࡜࡞ࡿ

ᐃ

ࡋ࡚ࠊᵝࠎ࡞SSD࡛⥺㔞ࢆ☜ㄆࡍࡿ࡭ࡁ࡛࠶ࡿࠋ

ᐃ㡯┠ࡣࠊ⥺㔞ィ⟬ࢩࢫࢸ࣒㸦TPSࠊ௨ୗ࡟ࠊSSD ࡀኚ໬ࡋࡓሙྜ࡟῝㒊⥺㔞࡟ᙳ㡪ࡍ

MU ィ⟬ࢩࢫࢸ࣒ࠊ࡞࡝㸧࡟౫Ꮡࡍࡿࠋࡲࡓ≉Ṧ࡞ࡿᅉᏊࢆ♧ࡍࠋගᏊ⥺ࡢ῝㒊⥺㔞ࡣ SSD ࡢኚ໬࡟ࡼ

἞⒪ἲ࡛ࡣ἞⒪ィ⏬ࢩࢫࢸ࣒ࡢṇ☜ࡉࢆ☜ㄆࡍࡿࡗ࡚ྛᡂศࡀ␗࡞ࡿኚ໬ࢆ♧ࡍࡓࡵࠊ༢⣧࡞㊥㞳⿵

ࡓࡵࡢ㏣ຍࢹ࣮ࢱࢆ

ᐃࡍࡿᚲせࡀ࠶ࡿ ࠋࡇࢀࡽ඲࡚ࡢࢹ࣮ࢱࡣࢫ࢟ࣕࣥ
࢖ࣥࢺ⥺㔞

2

ᐃ࡜㠀ࢫ࢟ࣕࣥ

ᐃ㸦࣏ᐃ㸧࡟ࡼࡾྲྀᚓࡉࢀࡿࠋࢫ࢟ࣕࣥ

ᐃࡣࠊ↷ᑕ᮲௳㸦౛㸸↷ᑕ㔝ࢧ࢖ࢬࠊSSDࠊ⿵ຓჾල

ṇ࡛ࡣ୙༑ศ࡛࠶ࡿࠋࡇࡢࡓࡵࠊᣦᐃࡉࢀࡓ SSD ࡛ᐃࢆᚲࡎᐇ᪋ࡋࠊ␗࡞ࡿ SSD ࡛ᚓࡓࢹ࣮ࢱࡣᩚ

ࡢྜᛶࢆ☜ㄆࡍࡿࡓࡵࡢ QA ࡜ࡋ࡚఩⨨௜ࡅࡿ࡭ࡁ࡛
࠶ࡿࠋ㸸ࡢ᭷↓ࠊ➼㸧ࢆᅛᐃࡋࡓ≧ែ࡛␗࡞ࡿ఩⨨ࡢ⥺㔞ࢆ㐃⥆ⓗ࡟ᐃࡍࡿ᪉ἲ࡛࠶ࡾࠊ῝ࡉ᪉ྥࡸ㍈እ᪉ྥࡢ⥺㔞ኚ໬ࢆ

ᐃࡍࡿࠋ୍᪉࡛ࠊ㠀ࢫ࢟ࣕࣥ↷ᑕ᮲௳ࢆᵝࠎ࡟ኚ໬ࡉࡏ࡚⥺㔞ࡢኚ໬ࢆxᐃࡣΰධ㟁Ꮚ㸦Electron contamination㸧㸸⾲㠃⥺㔞࡜ࣅࣝࢻ࢔ࢵࣉ㡿ᇦ࡛ࡣΰධ㟁Ꮚࡀ」㞧࡟ᐃࡍᙳ㡪ࡍࡿࠋΰධ㟁Ꮚࡣ↷ᑕ㔝ࢧ࢖ࢬࠊගᏊ࢚

ࡿ᪉ἲ࡛ࠊ㏻ᖖࡣ⥺㔞ࢆࣀ࣮࣐ࣛ࢖ࢬࡍࡿᇶ‽῝࡛ࢿࣝࢠ࣮ࠊSSDࠊࣅ࣮࣒ಟ㣭ჾලࠊࣅ࣮࣒ゅᐃࡍࡿࠋTable I ࡟♧ࡋࡓࢫࣉࣞࢵࢻࢩ࣮ࢺࡣከ㔞ᗘ࡞࡝ࢆྵࡴᵝࠎ࡞ᅉᏊ࡟ᙳ㡪ࡉࢀࡿ 90-101ࠋࡢࢹ࣮ࢱࡢయ⣔ⓗ࡞⟶⌮࡟᭷⏝࡛࠶ࡿࠋࡇࡢ࡜ࡁࠊ

ࡇࡢኚ໬ࡣ〇㐀ᴗ⪅࡟ࡼࡿ㐺ṇ࡞ᢏ⾡࡟ࡼྠ᫬࡟ࣇ࢓࢖ࣝྡ࡞࡝ࡶ୍ᣓࡋ࡚⟶⌮ࡍࡿᚲせࡀࡾྍ⬟࡞㝈ࡾపῶࡉࢀ࡚࠸ࡿࡀࠊ㏻ᖖࠊྛ

࠶ࡿࠋ

SSD ࡟࠾ࡅࡿΰධ㟁Ꮚࡢኚ໬ࡣ⿵ṇ࡛ࡁ࡞
࠸ 102, 103ࠋΰධ㟁Ꮚࡢ┦ᑐⓗ࡞㔞ࡣ✵Ẽᒙࡢ

IV.A.1. ῝㒊⥺㔞㛗ࡉ㸦ҸSSD㸧࡛ኚ໬ࡋࠊ㛗࠸ SSD ࡛ࡣ࣊ࢵPDD ࡣ୍ᐃࡢ SSD㸦㏻ᖖࡢࣜࢽ࢔ࢵࢡ࡛ࡣ⥺※ᅇ㌿㍈㛫㊥㞳࡛࠶ࡿ 100 cm㸧࡛㦂࡟࠾ࡅࡿ PDDࢻᩓ஘㟁Ꮚࡢ✵୰ᩓ஘ࡀቑ኱ࡍࡿࡓࡵΰධ

ᐃࡍࡿࠋཷࡅධࢀヨᐃ࡛ࡣ≉ᐃࡢ

ᐃᶵჾ㸦౛࠼ࡤࠊ

㟁Ꮚࡣῶᑡࡍࡿࠋ
x୍ḟ⥺㔞㸦Primary dose㸧㸸୍ḟ⥺㔞ࡣ␗࡞ࡿ

ᕤሙฟⲴ᫬ࡢࣅ࣮࣒ࣃ࣓࣮ࣛࢱ࡟୍⮴ࡉࡏࡿࡓࡵࠊ

SSD ࡟ᑐࡋ࡚㊥㞳ࡢ㏫஧஌๎ࢆ㐺⏝ࡍࡿࡇࣜࢽ࢔ࢵࢡࡢタ⨨⪅ࡀ⏝࠸ࡿ Wellhofer Buddelschif࡜࡛⿵ṇྍ⬟࡛࠶ࡿࠋࡓࡔࡋࠊഃ᪉㟁Ꮚᖹ⾮ࡸ PTW ࢩࢫࢸ࣒࡞࡝㸧ࡀ⏝࠸ࡽࢀࡿࠋࡋ࠿ࡋࠊࡇ

ࡀᡂ❧ࡋ࡞࠸ᑠ↷ᑕ㔝࡛ࡣ῝ࡉ࡟ࡼࡾ↷ᑕࢀࡽࡢࢹ࣮ࢱࡣࣅ࣮࣒ࣔࢹࣜࣥࢢࡸࢥ࣑ࢵࢩࣙࢽ

㔝ࢧ࢖ࢬࡀኚ໬ࡋࠊᖹ⾮ࣞ࣋ࣝࡀኚ໬ࡍࡿࡓ

ࣥࢢ࡛⏝࠸࡚ࡣ࡞ࡽ࡞࠸ࠋࡇࡢ௚࡟ࠊࢫ࢟ࣕࣥ㏿ᗘࠊࡵ⿵ṇࡣᅔ㞴࡛࠶ࡿࠋࢫࢸࢵࣉࠊࢤ࢖ࣥ࡞࡝࡟ὀពࡀᚲせ࡛࠶ࡿ㸦III ❶ཧ↷㸧ࠋࡲࡓࠊ῝㒊⥺㔞ࡢxᐃ࡛ࡣỈ㠃ࡢἼ❧ࡕࢆ᭱ᑠ࡟ࡍࡿࡓࡵࠊࢱࣥࢡࡢᗏ࠿ࡽ

ᩓ஘⥺㔞㸦Scatter dose㸧㸸኱↷ᑕ㔝࡛ࡣࣇ࢓ࣥࢺ࣒ෆ࡛⏕ࡌࡿᩓ஘⥺ࡀቑ኱ࡍࡿࡓࡵ㊥ᐃࢆ㛤ጞࡍࡿ࡞࡝

㞳ࡢ㏫஧஌ࡢᙳ㡪ࡀᙅࡲࡿࠋࡇࡢᩓ஘⥺ࡣ␗࡞ࡿ SSD ࡛ྲྀᚓࡉࢀࡿ㸦ΰධ㟁Ꮚࡢ฿㐩῝ࢫ࢟ࣕࣥ᪉ྥࢆ⪃៖ࡍࡿᚲせࡀ࠶ࡿࠋᗘ௨㝆ࡢ㸧PDD ࡀᕪ␗ࢆ⏕ࡌࡿ୺࡞ཎᅉ࡛
IV.A.1.a. ᶆ‽ⓗ࡞ SSD ࡜㠀ᶆ‽ⓗ࡞ SSDྛ✀ࡢࢫࢣ࣮ࣜࣥࢢᡭᢏ࡛⏕ࡌࡿㄗᕪࢆ᭱ᑠ࡟

࠶ࡿࠋxࡍࡿࡓࡵࠊࢹ࣮ࢱࡣ⮫ᗋ࡛ࡢࢭࢵࢺ࢔ࢵࣉ᮲௳࡟㏆࣊ࢵࢻᩓ஘⥺㸦Head scatter㸧㸸࣊ࢵࢻᩓ஘⥺ࡣ࢞ࣥࢺࣜ࣊ࢵࢻෆ࡛⏕ࡌࡓᩓ஘⥺࡛࠶ࡾࠊ࠸᮲௳࡛ྲྀᚓࡍࡿࠋ୍⯡ⓗ࡟࢔࢖ࢯࢭࣥࢺࣜࢵࢡ࡞
↷ᑕἲ࡛ࡣᰯṇ῝ࡀ 10 cmࠊSSDࡀ 90 cm࡛࠶ࡿࡓࡵࠊ

38

ヂ⪅ὀ3

AAPM TG-51 ࡞࡝

IV. 光子線のビームデータ

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)ࡑࡢ୺⥺※㸦ࣇࣛࢵࢺࢽࣥࢢࣇ࢕ࣝࢱ㸧࠿ࡽṦ࡞἞⒪ἲ࡛ࡣࠊ῝㒊⥺㔞ࠊTPR ࡲࡓࡣ TMRࠊ⥺

ࡢ㏫஧஌࡟ᚑ࠺ࠋ࣊ࢵࢻᩓ஘ගᏊࡢᐇຠ⥺※㔞ࣉࣟࣇ࢓࢖ࣝࡣࠊAAPM ࡢ࣏࣮ࣞࢺ࡟グ㏙ࡉࢀ࡚఩⨨ࡣࣇࣛࢵࢺࢽࣥࢢࣇ࢕ࣝࢱ௜㏆࡟࠶ࡿ࠸ࡿࡼ࠺࡟ࡑࢀࡒࢀᘏ㛗ࡋࡓ㊥㞳࡛ྲྀᚓࡍࡿᚲせࡓࡵࠊ㏫஧஌ࡢᙳ㡪ࡣࢱ࣮ࢤࢵࢺ࠿ࡽࡢ┤᥋

ࡀ࠶ࡿ 23,24ࠋࡋ࠿ࡋࠊỈᵴࡢࢧ࢖ࢬࡀ㝈ᐃࡉࢀࡿࡓ

ගᏊ࡜࣊ࢵࢻᩓ஘ගᏊ࡛␗࡞ࡿࠋࡉࡽ࡟ࠊ

ࡵࡇࢀࡽࡢࢹ࣮ࢱ཰㞟ࡣᅔ㞴࡛࠶ࡿࠋࡉࡽ࡟ࠊࡇࢀ

PDD㸦┤᥋ගᏊ࡜࣊ࢵࢻᩓ஘ගᏊࡢΰྜ㸧࡜ࡽࡢࢹ࣮ࢱࡣ༑ศ࡞ࢧ࢖ࢬࡢࣇ࢓ࣥࢺ࣒ࢆ⏝࠸ࡓഃ᪉ࡢ⥺㔞ࣉࣟࣇ࢓࢖ࣝ㸦ᐇຠ⥺※఩⨨ࡀࣇ࣏࢖ࣥࢺ⥺㔞

ᐃ࡟ࡼࡗ᳨࡚ドࡍࡿᚲせࡀ࠶ࡿࠋ࢓ࣥࢺ࣒࡟㏆࡙ࡃࡓࡵࠊ࣊ࢵࢻᩓ஘ගᏊࡣ┤xx᥋ගᏊࡼࡾእഃ࡟ᗈࡀࡿ㸧࡛␗࡞ࡿᙳ㡪ࢆࡶ

IV.A.2. ⤌⧊᭱኱⥺㔞ẚ࣭⤌⧊ࣇ࢓ࣥࢺ࣒⥺㔞ẚࡓࡽࡍࠋ㸦TMR/TPR㸧࢚ࢿࣝࢠ࣮㸦Energy㸧㸸⾲㠃࡛ྠࡌ↷ᑕ㔝ࢧTMR ࡢᐃࡣከ኱࡞᫬㛫ࢆせࡍࡿࠋỈࣇ࢓ࣥࢺ࢖ࢬ࡛࠶ࡗ࡚ࡶࠊSSD ࡀ␗࡞ࡿሙྜࡣ␗࡞ࡿ

࣒࡟ࡼࡗ࡚ࡣࠊ᪤▱ࡢỈ㔞ࢆ࣏ࣥࣉ࡛Ữࡳࡔࡍࡇ࡜

ᐇຠ࢚ࢿࣝࢠ࣮ࢫ࣌ࢡࢺࣝࢆ♧ࡍࠋࡇࢀࡣᩓ

࡟ࡼࡗ࡚ TMR/TPR ࢆᐃࡍࡿࢩࢫࢸ࣒ࢆ᭷ࡍࡿࡀࠊ

஘⥺ࡢᡂศࡀ␗࡞ࡿࡓࡵ࡛ࠊ㍈እ࡟࠾ࡅࡿ⥺ࡑࢀࡒࢀ࣏࢖ࣥࢺ⥺㔞ᐃ࡟ࡼࡾṇ☜ࡉࢆ᳨ドࡍ㉁ࡢ㌾໬ࡣ㍈እゅᗘ࡟౫Ꮡࡍࡿࠋࡿᚲせࡀ࠶ࡿࠋ᭱ࡶ⡆༢࡞ TMR/TPR ࡢྲྀᚓἲࡣࠊ

༙ᙳ㸦Penumbra㸧㸸㟁㞳⟽ࡀࢧ࢖ࢬ࡟ࡼࡗ࡚῝㒊⥺㔞᭷ពࡢᗈࡀࡾ㛵ᩘࢆᣢࡘࡓࡵࠊ㟁㞳⟽ࢆ⏝࠸ࡃࡢࢯࣇࢺ࢙࢘࢔࡛ࡣ BJR Supplement 25104 ࡟♧ࡉᐃࡋࡓ࠶ࡿ SSD ࡢ༙ᙳ࠿ࡽ௚ࡢ SSD ࡢࢀࡓ Khan ࡽ 88 ࡢᡭἲࢆ᥇⏝ࡋࡓኚ᥮ࣉࣟࢢ࣒ࣛࡀ

༙ᙳࢆỴᐃࡍࡿࡇ࡜ࡣᅔ㞴࡛࠶ࡿࠋᑠᆺࡢ᳨

⤌ࡳ㎸ࡲࢀ࡚࠸ࡿࠋ῝ࡉ d ࡜↷ᑕ㔝 rd ࡢ TMR ࡣࠊฟჾࡀ౑⏝࡛ࡁ࡞࠸ሙྜࠊࣉࣟࣇ࢓࢖ࣝࡣࢹ

PDD ࠿ࡽḟᘧ࡛⟬ฟ࡛ࡁࡿࠋ

࡚ᐃ࠿ࡽኚ᥮ࡋ࡚సᡂࡍࡿ᪉ἲ࡛࠶ࡿࠋከ

ࢥ࣮ࣥ࣎ࣜࣗࢩࣙࣥ㸦㏫␚ࡳ㎸ࡳ✚ศ㸧࡛ᚓࡿࡇ࡜ࡀ࡛ࡁࡿ㸦Sec. IV A ཧ↷㸧ࠋ
TMR d , rd㸦ᑠ↷ᑕ㔝ࢆ㝖ࡃ㸧⡆༢࡞ QA ࡛ࡣࠊഹ࠿࡞ SSD

2
S p r , c d max
PDD c, d r , SSD
SSD  d.
2
S p r, cd
100
SSD  d max(2)ࡢ㐪࠸࡟ᑐࡋ࡚㏫஧஌๎࡟ࡼࡿ⿵ṇࡀྍ⬟࡛࠶ࡿࠋࡓࡔࡋࠊࡑࢀ௨እ࡛ࡣ␗࡞ࡿ SSD ࡛ᚓࡓࢹ࣮ࢱࢆ⿵
ṇࡋ࡚⏝࠸ࡿࡇ࡜ࡣ᥎ዡࡉࢀ࡞࠸ࠋ

ࡣ኱↷ᑕ㔝ࠊᑠ↷ᑕ㔝࠾ࡼࡧ῝㒊࡛ᚲࡎ᳨ドࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋࡲࡓࠊࡇࢀࡽࡢ⾲ࡢసᡂ࡟ࡣ PDD

IV.A.1.b. ␗࡞ࡿ SSD ࡟࠾ࡅࡿ PDD ࡢኚ᥮
PDD ࡣࠊSSD ୍ᐃࡢ἞⒪ࡸࡑࡢ௚ࡢ῝㒊⥺㔞ࢹ࣮ࢱ㸦౛࠼ࡤ TMR/TPR㸧ࢆỴᐃࡍࡿࡓࡵ࡟⏝࠸ࡽࢀࡿࠋ័⩦ⓗ࡟ PDD ࡣ SSD=100 cm ࡛ホ౯ࡉࢀࡿࡀࠊ
SSD=90 cm ࡞࡝࡛ࡶᐃࡉࢀࡿࡇ࡜ࡀ࠶ࡿࠋ▷࠸SSD ࡛ࡣ኱↷ᑕ㔝ࡢᐃ࡛༑ศ࡞ࣇ࢓ࣥࢺ࣒ࢧ࢖

ࢬࢆᐜ᫆࡟‽ഛ࡛ࡁࡿࠋPDD ࡣ↷ᑕ㔝㸦s㸧࡜῝ࡉ㸦d㸧࡟ຍ࠼ SSD ࡢ㛵ᩘ࡛࠶ࡿࠋ␗࡞ࡿ SSD ࡛ኚ᥮ࡢጇᙜᛶࢆ☜ㄆࡍࡿࡓࡵࠊᘧ(2)࡛ᚓࡓ TMR

ᐃࡉࢀࡓ PDD ࡢ㛵ಀࢆồࡵࡿ᪉ἲࡀᵝࠎ࡞ᩥ⊩࡛ሗ࿌ࡉࢀ࡚࠸ࡿ 88,104ࠋ
IV.A.1.c. ᘏ㛗ࡋࡓ㊥㞳࡟࠾ࡅࡿࣅ࣮࣒ࢹ࣮ࢱ
඲㌟↷ᑕ㸦total body irradiation, TBI㸧ࡸ඲⓶⭵㟁ࡢ⿵㛫ࡀᚲせ࡛࠶ࡿࡓࡵࠊᑠ↷ᑕ㔝ࡢ TMR ࡛ࡣࡉࡽ࡟ᑠ↷ᑕ㔝ࡢ PDD ࡀᚲせ࡛࠶ࡿࠋ࣋ࣥࢲ࣮ࡀᥦ
౪ࡍࡿࢯࣇࢺ࢙࢘࢔ࢆ⏝࠸࡚ PDD ࠿ࡽ TMR ࡟ኚ᥮ࡍࡿሙྜࠊᑠ↷ᑕ㔝࡜῝㒊࡛ࡣእᤄ࡟ࡼࡿㄗᕪࡀ⏕ࡌ࡚࠸࡞࠸ࡇ࡜ࢆᚲࡎ☜ㄆࡍࡿᚲせࡀ࠶ࡿࠋ࣏࢖ࣥ
ࢺ⥺㔞ᐃ࡟ࡼࡾࡇࢀࡽࡢጇᙜᛶࢆ☜ㄆࡍࡿࡇ࡜

ࢆ᥎ዡࡍࡿࠋ
IV.A.3. ⾲㠃⥺㔞࡜ࣅࣝࢻ࢔ࢵࣉ㡿ᇦ⾲㠃⥺㔞ࡣ⿦⨨࡟౫Ꮡࡋࠊ↷ᑕ㔝ࢧ࢖ࢬࠊ⥺※⾲㠃㛫㊥㞳ࠊࣅ࣮࣒ಟ㣭ჾල࠾ࡼࡧࣅ࣮࣒ධᑕゅᗘ࡞࡝ከࡃࡢࣃ࣓࣮ࣛࢱࡢᙳ㡪ࢆཷࡅࡿ 97, 105-115ࠋ㏻ᖖࠊ

Ꮚ⥺↷ᑕ㸦total skin electron irradiation㸧ࡢࡼ࠺࡞≉39

医学物理 第 33 巻 第 1 号

IV. 光子線のビームデータ

FIG. 10. Surface and buildup dose for 10×10 cm2 field of a 6 MV
beam with various detectors. The actual surface dose is also marked by
the arrow.

ࣜࢽ࢔ࢵࢡࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ࡛ࡣ⾲㠃⥺㔞ࡢᐃࡀྵࡲࢀࡿࠋࣅࣝࢻ࢔ࢵࣉ㡿ᇦ࡜ྠᵝࠊ⾲㠃௜㏆ࡣᛴᓧ࡞⥺㔞໙㓄࡛࠶ࡿࡓࡵ᳨ฟჾࡢ㑅ᢥ࡟⣽ᚰࡢὀពࡀᚲせ࡛࠶ࡿ 115-118ࠋFig. 10 ࡣ␗࡞ࡿ᳨ฟჾ
࡛ᐃࡋࡓࣅࣝࢻ࢔ࢵࣉ㡿ᇦ࡜⾲㠃⥺㔞ࢆ♧ࡍࠋ㏻ᖖࠊࣅ࣮࣒᪉ྥࡢ᳨ฟჾ᭷ឤ㒊ࡢ኱ࡁࡉࡣྍ⬟࡞㝈ࡾᑠࡉࡃࡍࡿࠋ⾲㠃⥺㔞ࡢᐃ࡛ࡣ㉮ᰝᘧࡢ

ᐃჾࢆ౑⏝ࡋ࡞࠸ࡇ࡜ࢆᙉࡃ᥎ዡࡍࡿࠋ
⾲㠃⥺㔞ࡢFIG. 11. Effect of chamber orientation on photon beam profiles for a
10×10 cm2 fields: (a) long axis scan, (b) short axis scan with various
size detectors. Only half scans are shown.

ᐃ࡛ࡣእᤄ㟁㞳⟽ࡀ᭱㐺࡛࠶ࡿࠋࡋ

࠿ࡋࠊධᡭᅔ㞴࡛࠶ࡾࠊ㠀ᖖ࡟ᐃ᫬㛫ࡀ࠿࠿ࡿၥ

㢟ࡀ࠶ࡿࠋࡼࡗ࡚ࠊࡑࡢ௦⏝࡜ࡋ࡚ᖹ⾜ᖹᯈᙧ㟁㞳⟽ࡀ⾲㠃⥺㔞࡜ࣅࣝࢻ࢔ࢵࣉ㡿ᇦࡢ⥺㔞ᑠ↷ᑕ㔝࡜⥺㔞໙㓄ࡀᛴᓧ࡞㡿ᇦ࡟࠾ࡅࡿ⥺㔞ࣉࣟࣇ࢓࢖ࣝ㸦㸻㍈እ⥺㔞ẚ㸧ࡢᐃ୍࡛ᐃ࡛ࡣࠊ᳨ฟჾ

⯡ⓗ࡟⏝࠸ࡽࢀ࡚࠸ࡿࡀࠊᖹ⾜ᖹᯈᙧ㟁㞳⟽ࡣࣅࣝࡢタ⨨᪉ྥࡀᴟࡵ࡚㔜せ࡛࠶ࡿࠋFig. 11 ࡟♧ࡍࡼ࠺ࢻ࢔ࢵࣉ㡿ᇦࠊ≉࡟⾲㠃㏆ഐ࡛⥺㔞ࢆ㐣኱ホ౯ࡍࡿ࡟ࠊẚ㍑ⓗ኱ࡁ࠸↷ᑕ㔝࡟࠾ࡅࡿ⥺㔞ࣉࣟࣇ࢓࢖ࣝ

90, 119ࠋࡇࢀࡣእᤄ㟁㞳⟽࡜ẚ㍑ࡋ࡚㟁ᴟ㛫㝸ࡀ኱ࡁᐃ࡛ࡣࠊ㐺ษ࡞᳨ฟჾ࡜ࡑࡢタ⨨᪉ྥࡀ㑅ᢥࡉࢀ࠸ࡇ࡜࡜ࠊ࣮࢞ࢻࣜࣥࢢࡀᑠࡉ࠸ࡇ࡜࡟㉳ᅉࡍࡿࠋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋFig. 11 ࡣࣉࣟࣇ࢓࢖ࣝ

ࡼࡗ࡚ࠊᑠࡉ࠸㟁ᴟ㛫㝸࡜ᖜࡢᗈ࠸࣮࢞ࢻࣜࣥࢢࢆ

ࡅࡿయ✚ᖹᆒຠᯝࢆ♧ࡋࠊࢫ࢟ࣕࣥ᪉ྥ࡛᭷ឤ㒊ࡀഛ࠼ࡓ㟁㞳⟽ࢆ⏝࠸ࡿࡇ࡜࡛ࡇࡢ୙ṇ☜ࡉࡣపῶⷧ࠸㸦✵㛫ศゎ⬟ࡀ㧗࠸㸧᳨ฟჾࡀࣉࣟࣇ࢓࢖ࣝ

࡛ࡁࡿࠋࡉࡽ࡟ࠊ㟁㞳⟽ࡢᴟᛶຠᯝࡣṇ㈇ࡢᴟᛶ࡛
90ᚓࡽࢀࡓㄞࡳ್ࢆᖹᆒࡍࡿࡇ࡜࡛⿵ṇྍ⬟࡛࠶ࡿ ࠋᐃ࡟࠾ᐃ࡟㐺ࡋ࡚࠸ࡿࠋ
㏻ᖖࠊࢥ࣑ࢵࢩࣙࢽࣥࢢ࡛ࡣ in-plane㸦gun-target

ⷧᒙ TLDࠊ᭷ឤయ✚ࡢᑠࡉ࠸ࢲ࢖࣮࢜ࢻ᳨ฟჾࠊ

᪉ྥ㸧࡜ cross-plane㸦left-right ᪉ྥ㸧ࡢ⥺㔞ࣉࣟࣇ

MOSFETࠊࣛࢪ࢜ࢡ࣑ࣟࢵࢡࣇ࢕࣒ࣝ࡟ࡼࡿ⾲㠃⥺࢓࢖ࣝࡀᚲせ࡛࠶ࡿࠋin-plane ࡜ cross-plane ࢆ௵ព㔞ࡢᐃࡶሗ࿌ࡉࢀ࡚࠸ࡿ

117,120,121ࠋ࡟㑅ᢥ࡛ࡁࡿሙྜࠊcross-plane ࣉࣟࣇ࢓࢖ࣝࢆྲྀᚓ
ࡍ࡭ࡁ࡛࠶ࡿࠋࡇࢀࡣࠊ୍㒊ࡢ⿦⨨࡛ࡣຍ㏿㟁Ꮚࢆ

IV.A.4. ࣅ࣮࣒ࣉࣟࣇ࢓࢖ࣝ

ㄪᩚࡍࡿ gun-target ᪉ྥ࡛ࠊ㠀ᑐ⛠ᛶࡸᖹᆠᛶࡀḞ

IV.A.4.a. ࣉࣟࣇ࢓࢖ࣝ㸦༙ᙳ㒊࡜㍈እ⥺㔞ẚ㸧ዴࡍࡿྍ⬟ᛶࡀ࠶ࡿࡓࡵ࡛࠶ࡿࠋcross-plane ࡢࣉࣟ40

IV. 光子線のビームデータ

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)ࣇ࢓࢖ࣝࡣᏳᐃࡋ࡚࠾ࡾࠊࢹ࣮ࢱ཰㞟࡛ࡣࡇࡢ㉮ᰝࣇ࢓࢖ࣝࡶ᪉ྥࢆ㑅ᢥࡍࡿᚲせࡀ࠶ࡿࠋࡾᑠࡉ࠸㛫㝸࡛ᐃࡍࡿࠋ⥺㔞໙㓄ࡀᛴᓧ࡞㡿ᇦ࡛ࡣࡼᐃࡍࡿᚲせࡀ࠶ࡿࠋ≀⌮࢙࢘ࢵࢪ⥺㔞ࣉࣟࣇ࢓࢖ࣝࡣࠊࢥ࣑ࢵࢩࣙࢽࣥࢢᮇ㛫࡟࡛ࡣ໙㓄᪉ྥ࡜㠀໙㓄᪉ྥ࡛ࣅ࣮࣒ࡢῶᙅࡀ⏕ࡌ

TPS ࡬ࡢධຊࡸࡑࡢ௚ࡢᡭィ⟬ࠊᕷ㈍ࡢࢯࣇࢺ࢙࢘

ࡿࠋ኱↷ᑕ㔝ࡢ㎶⦕࡛ࡣ࢙࢘ࢵࢪ࡟ᩳධᑕࡍࡿࡇ࡜

࢔ࢆ⏝࠸ࡓ MU ィ⟬⏝࡟ྲྀᚓࡍࡿࠋ ᐃ᮲௳ࡣ TPS

࡟ࡼࡾࠊ㍈እ࡛࠶ࡿ࡯࡝ῶᙅࡀ኱ࡁ࠸ࡇ࡜࡟ὀពࡀ

࡟౫Ꮡࡍࡿࡀࠊከࡃࡢ TPS ࡛ࡣ࣮࢜ࣉࣥ࡜࢙࢘ࢵࢪᚲせ࡛ࠊࡇࢀࢆホ౯ࡍࡿࡓࡵࠊ㠀໙㓄᪉ྥ࡛ࡶࢹ࣮

↷ᑕ㔝࡟ࡘ࠸࡚༙ᙳ㒊࡜㍈እ⥺㔞ẚࢆࣔࢹࣝ໬ࡍ

ࢱࢆྲྀᚓࡍࡿ 123, 124ࠋࡿࡓࡵࠊᑠ↷ᑕ㔝࠿ࡽ᭱኱↷ᑕ㔝ࡢ⥺㔞ࣉࣟࣇ࢓࢖ࣝࢆᚲせ࡜ࡍࡿࠋࢹ࣮ࢱ㛫㝸ࡣ༙ᙳ㒊࡛ᑡ࡞ࡃ࡜ࡶ

IV.A.4.d. ࢯࣇࢺ㸦࢚ࣞࢡࢺࣟࢽࢵࢡ㸧࢙࢘ࢵࢪ

1 mmࠊࡑࡢ௚ࡣ 2 mm ࢆ㉸࠼࡞࠸㛫㝸ࡀᮃࡲࡋ࠸ࠋ

ࢯࣇࢺࡲࡓࡣ࢚ࣞࢡࢺࣟࢽࢵࢡ࢙࢘ࢵࢪ㸦ࢲ࢖ࢼࣉࣟࣇ࢓࢖ࣝࢹ࣮ࢱ࠿ࡽ㍈እ⥺㔞ẚࡢ⾲ࢆసᡂࡍ࣑ࢵࢡ࢙࢘ࢵࢪࠊࣂ࣮ࢳ࢙ࣕࣝ࢘ࢵࢪ㸧ࡢ⥺㔞ࣉࣟࡿ㝿ࡣ୰ᚰ㍈ࡢ್࡛つ᱁໬ࡋࠊ࢔࢖ࢯࢭࣥࢱ㠃࡛ࡢࣇ࢓࢖ࣝࢆ㍈እ㊥㞳࡟⦰ᑻࢆྜࢃࡏࡿᚲせࡀ࠶ࡿࠋከࡃࡢࢫ࢟

ࢢࢩࢫࢸ࣒࡜ࡣ␗࡞ࡿ

ࣕࢽࣥࢢࢩࢫࢸ࣒࡟௜ᒓࡍࡿࢯࣇࢺ࢙࢘࢔ࡣࡇࡢ

ࢺ࢙࢘ࢵࢪࡣࣅ࣮࣒↷ᑕ᫬࡟ࢥ࣓࣮ࣜࢱࢆ㛤㛢㥑ᶵ⬟ࢆഛ࠼࡚࠸ࡿࠋ

ືࡍࡿࠋࡇࡢሙྜࡢ࢙࢘ࢵࢪࣉࣟࣇ࢓࢖ࣝࡣ༢୍ࡢ

⥺㔞ࣉࣟࣇ࢓࢖ࣝࡢ

ᐃᩘࡣ TPS ࡟౫Ꮡࡋࠊᐃࡵ

ᐃࡍࡿࡓࡵ࡟ࡣࠊ୍⯡ⓗ࡞ࢫ࢟ࣕࢽࣥ
ᐃᶵჾࡀᚲせ࡛࠶ࡿࠋࢯࣇ

㟁㞳⟽ࢆ౑⏝ࡍࡿᶆ‽ࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡛

ࡽࢀࡓ↷ᑕ㔝࡜῝ࡉ࡛ྲྀᚓࡍࡿࠋࣅ࣮࣒ࡢᇶᮏⓗ࡞ࡣᙧ≧ࡣ῝ࡉࡲࡓࡣ↷ᑕ㔝࡛኱ࡁࡃኚ໬ࡋ࡞࠸ࡓࡵࠊ

ࡋࡓࣉࣟࣇ࢓࢖ࣝࡣ㐣๫࡟ྲྀᚓࡍࡿᚲせࡣ࡞࠸ࠋ㏻ᖖࠊ

ࢫࢸ࣒ࡢ㥑ື㒊࡟࣐࢘ࣥࢺ࡛ࡁࡿ㸯ḟඖ᳨ฟჾ㸦ิ22ᐃ࡛ࡁ࡞࠸ࠋྛ

ᐃⅬ࡛඲ᩓ஘⥺ࡢᙳ㡪ࢆ⪃៖ᐃࢆ⾜࠺ࡓࡵࠊࣇ࢕࣒ࣝࡸࠊࢫ࢟ࣕࢽࣥࢢࢩ

6 × 6 cm ࡲ࡛ࡣ 1 cm 㛫㝸ࡢ↷ᑕ㔝ࠊ10 × 10 cm ௨ᆺ᳨ฟჾࠊ⣲Ꮚࡣ㟁㞳⟽ࡲࡓࡣࢲ࢖࣮࢜ࢻ㸧44, 45, 59

ୖ࡛ࡣ 5 cm 㛫㝸ࡢ↷ᑕ㔝࡛ྲྀᚓࡍࢀࡤ༑ศ࡛࠶ࡿࠋ

ࡀ⏝࠸ࡽࢀࡿࠋࡋ࠿ࡋࠊከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸࡲࡓ῝ࡉ࡟ࡘ࠸࡚ࡣ 5-7 ✀㢮ࡢ῝ࡉ࡛ྲྀᚓࡋࠊdmax࣒࡛ࡣࡇࡢ࣐࢘ࣥࢺ࢜ࣉࢩࣙࣥ࡞࡝⤌ࡳྜࢃࡏ࡚

ࢆྵࡴ 5 cm 㛫㝸࡛༑ศ࡛࠶ࡿࠋࡲࡓࠊ୍㒊ࡢ TPS౑⏝࡛ࡁࡿ᳨ฟჾ࡟ไ㝈ࡀ࠶ࡾࠊࡲࡓ᪋タ࡟ࡼࡗ࡚࡛ࡣ in-plane ࡜ cross-plane ࡟ຍ࠼ᑐゅ⥺ୖࡣ㈝⏝ࡶၥ㢟࡜࡞ࡿࠋࡑࡢ௚ࡢ㑅ᢥ⫥࡜ࡋ࡚ Profiler

㸦diagonal-plane㸧ࡢࣉࣟࣇ࢓࢖ࣝࡀᚲせ࡛࠶ࡿࠋ㸦Sun Nuclear, Melbourne, FL㸧ࡢࡼ࠺࡞ࢲ࢖࣮࢜ࢻ
࢔ࣞ࢖࡜ࠊ࡯ࡰỈ➼౯࡜ࡉࢀࡿᅛయࣇ࢓ࣥࢺ࣒ࢆ⏝IV.A.4.b. ࢫࢱ࣮ࣃࢱ࣮ࣥ

࠸࡚ᑡ࡞ࡃ࡜ࡶ 20 cm ࡲ࡛ࡢ␗࡞ࡿ῝ࡉ࡛ᐃࡍࡿ୍㒊ࡢ TPS ࢔ࣝࢦࣜࢬ࣒࡛ࡣࢥ࣓࣮ࣜࢱᅇ㌿㍈

᪉ἲࡀ࠶ࡿࠋࢲ࢖࣮࢜ࢻ࢔ࣞ࢖ࡣỈ୰ࢫ࢟ࣕࣥ࡜Ⰻ

࡜ᆶ┤࡞㠃ࡢ࠸ࡃࡘ࠿ࡢゅᗘ࡛⥺㔞ࣉࣟࣇ࢓࢖ࣝ

ዲ࡞୍⮴ࢆ♧ࡋ࡚࠾ࡾ 45ࠊTPS ࡬ࡢࢹ࣮ࢱ㌿㏦ࡀྍ

ࡀᚲせ࡞ሙྜࡀ࠶ࡿࠋࡇࡢ⥺㔞ࣉࣟࣇ࢓࢖ࣝࡣ୍⯡⬟࡛࠶ࡿሙྜࡀከ࠸ࠋࡓࡔࡋࠊࢲ࢖࣮࢜ࢻ࢔ࣞ࢖ࡣ

ⓗ࡟ 10r㛫㝸ࠊ᭱኱↷ᑕ㔝ࡢ dmax ࡲࡓࡣỈ୰῝ࡉᐃྍ⬟࡞᭱኱↷ᑕ㔝ࡀ㝈ࡽࢀ࡚࠸ࡿࠋࡑࡢ௚ࡢ㑅

10 cm ࡛ྲྀᚓࡉࢀࠊࢫࢱ࣮ࣃࢱ࣮ࣥ㸦star-pattern㸧࡜ᢥ⫥࡜ࡋ࡚ࡣࠊࣇ࢕࣒ࣝࢆᅛయࣇ࢓ࣥࢺ࣒࡟ᤄධࡋࠊ

࿧ࡤࢀࡿࠋ୍㒊ࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣ≉ᐃࡢゅ⏬ീゎᯒࢯࣇࢺ࡛⥺㔞ࣉࣟࣇ࢓࢖ࣝࢆྲྀᚓࡍࡿ᪉

ᗘ࡛ࢫࢱ࣮ࣃࢱ࣮ࣥࢆྲྀᚓࡍࡿࢯࣇࢺ࢙࢘࢔ࡀෆ

ἲࡀ࠶ࡿࠋࣇ࢕࣒ࣝࢆ⏝࠸ࡓ⥺㔞ⶶࡉࢀ࡚࠸ࡿࠋࢯࣇࢺ࢙࢘࢔ࡀ฼⏝࡛ࡁ࡞࠸ሙྜࡣࠊ

ᛂ⟅᭤⥺ࢆసᡂࡋ࡚ᰯṇࢆ⾜࠺ᚲせࡀ࠶ࡾࠊࡲࡓ⮬⿦⨨ࡢ࢝࢘ࢳᅇ㌿ྎ࡛Ỉᵴࢆᅇ㌿ࡍࡿࡇ࡜࡛ྲྀᚓ

ື⌧ീᶵࡢ QA ࡶᚲ㡲࡛࠶ࡿࠋࣇ࢕࣒ࣝࢆ⏝࠸ࡓ⥺ࡍࡿࠋࢫࢱ࣮ࣃࢱ࣮ࣥࡣࣇࣛࢵࢺࢽࣥࢢࣇ࢕ࣝࢱࡢ

㔞≉ᛶ㸦ᙧ≧᝟ሗ㸧ࢆỴᐃࡍࡿࡓࡵࡢࡶࡢ࡛࠶ࡿࡢ࡛ࠊ

࣒ࢧ࢖ࢬ࡟ࡼࡿ

ࢥ࣓࣮ࣜࢱࢆᅇ㌿ࡋ࡚ྲྀᚓࡋ࡚ࡣ࡞ࡽ࡞࠸

122ᐃ࡛ࡣ⃰ᗘ-⥺㔞ᐃࡢၥ㢟Ⅼࡣ≉ᛶ᭤⥺ࡢ⥺㉁౫Ꮡᛶ 21 ࡜ࣇ࢕ࣝᐃ⠊ᅖࡢไ㝈࡛࠶ࡿࠋࠋ
IV.B. MLC ࢹ࣮ࢱ

IV.A.4.c. ≀⌮㸦ࣁ࣮ࢻ㸧࢙࢘ࢵࢪ
Table I(a)࡟♧ࡍࡼ࠺࡟ࠊ࢙࢘ࢵࢪ᪉ྥࡢ⥺㔞ࣉࣟ㏆ᖺࠊMLC ࡣࣜࢽ࢔ࢵࢡ࡟ᶆ‽ᦚ㍕ࡉࢀ࡚࠾ࡾࠊ
⏝㏵࡟ྜࢃࡏ࡚ᵝࠎ࡞ࢧ࢖ࢬ㸦ࣞࢠ࣮ࣗࣛࠊ࣑ࢽࠊ

41

医学物理 第 33 巻 第 1 号

IV. 光子線のビームデータ࣐࢖ࢡࣟ㸧ࡀ࠶ࡿࠋᶵᲔⓗᏳᐃᛶ࡜≉ᛶࡣᵝࠎ࡞〇࡞ࡃ࡜ࡶᡭィ⟬࡟ࡼࡿ⥺㔞ィ⟬࡛ࡣ௨ୗࡢࢹ࣮ࢱ

㐀ᴗ⪅࡟ᑐࡍࡿሗ࿌࡟ᇶ࡙࠸࡚ࠊ⿦⨨ࡢ࢔ࢡࢭࣉࢱ

ࢆ཰㞟ࡍࡿᚲせࡀ࠶ࡿࠋࣥࢫࢸࢫࢺ᳨࡛ドࡉࢀ࡞ࡅࢀࡤ࡞ࡽ࡞࠸

125-145

ࠋ㏻

ᖖࠊMLC ࡢྲྀᚓࡍ࡭ࡁࢥ࣑ࢵࢩࣙࢽࣥࢢࢹ࣮ࢱࡣ

IV.C.1. ඲ᩓ஘ಀᩘ

⮫ᗋ౑⏝࡟౫Ꮡࡍࡿࡀࠊࡑࢀ௨ୖ࡟ TPS ࡟౫Ꮡࡍࡿࠋ

἞⒪⿦⨨ࡢฟຊಀᩘࡣࠊᇶ‽࡜࡞ࡿỈ୰῝ࡉࡢ↷

MLC ࡢタィ࡜ࢥ࣑ࢵࢩࣙࢽࣥࢢ࡟㛵ࡍࡿヲ⣽ࡣᑕ㔝㸦10 × 10 cm2㸧࡟ᑐࡍࡿ௵ពࡢ↷ᑕ㔝ࡢ⥺㔞ẚ

AAPM Report 72 145 ࡜ IPEM Report 94 16 ࡛ᥦ౪ࡉࢀ

࡜ࡋ࡚ᐃ⩏ࡉࢀࡿࠋ඲ᩓ஘ಀᩘ㸦Total scatter factor,࡚࠸ࡿࠋࡋ࠿ࡋࠊୗグࡢࣃ࣓࣮ࣛࢱࡣྛගᏊ࢚ࢿࣝ

Scp㸧ࡣྠࡌ MU タᐃ್㸦M㸧࡟࠾࠸࡚࠶ࡿ↷ᑕ㔝࡜ࢠ࣮࡜ࠊ㔜ຊࡢᙳ㡪ࢆ᳨ドࡍࡿࡓࡵࠊᑡ࡞ࡃ࡜ࡶ 4ᇶ‽↷ᑕ㔝ࡢ⥺㔞ẚ࡜ࡋ࡚ᐃ⩏ࡉࢀࡿࠋ୧⪅ࡣ༑ศࡘࡢ࢞ࣥࢺࣜゅᗘ㸦0°ࠊ90°ࠊ180°ࠊ270°㸧࡛ᐃ㔞໬࡟኱ࡁ࠸Ỉࣇ࢓ࣥࢺ࣒୰࡛ᇶ‽῝࡟タ⨨ࡋࡓ⥺㔞ࡉࢀ࡞ࡅࢀࡤ࡞ࡽ࡞࠸

146, 147

ࠋ

ィ࡛

ᐃࡍࡿࠋ

S cp ( s )xග↷ᑕ㔝࡜ᨺᑕ⥺↷ᑕ㔝ࡢ୍⮴ࠋ

x

MLC 㛫㝽ࡢ₃ὤ㸦Inter-leaf leakage㸧x

MLC ୰ࡢ₃ὤ㏱㐣㸦Intra-leaf leakage㸧

x↷ᑕ㔝ෆࡢ Tongue and Groove ຠᯝx༙ᙳ㒊D( s, d ref ) M,
D( sref , d ref ) M(3)ࡇࡇ࡛ࠊD ࡣ௵ពࡢ↷ᑕ㔝 s ࡜ᇶ‽↷ᑕ㔝 sref ࡟ࡘ࠸࡚ࠊỈ୰ࡢᇶ‽῝ dref ࡛ᐃࡋࡓ⥺㔞࡛࠶ࡾࠊMࡣ MU タᐃ್࡛࠶ࡿࠋྛ↷ᑕ㔝࡛ഃ᪉ྥࡢࣅࣝࢻ࢔
ࢵࣉࢆ☜❧ࡉࡏࡿࡓࡵࠊ኱ࡁ࠸ࢧ࢖ࢬࡢỈࣇ࢓ࣥࢺຍ࠼࡚ࠊ⥺㔞ᐃ࡛㔜せ࡜࡞ࡿ఩⨨ࡢṇ☜ࡉࡣࣇ࢕࣒ࣝࡲࡓࡣ EPID ࡛Ỵᐃࡍࡿ

147, 149

ࠋMLC ࡢඛ➃࣒ࢆ౑⏝ࡍࡿࠋ῝ࡉ᪉ྥࡣᚋ᪉ᩓ஘ࢆ⪃៖ࡋࠊ᭱῝ࡢᐃⅬ࠿ࡽᑡ࡞ࡃ࡜ࡶ 10 cm ࡣࣇ࢓ࣥࢺ࣒ࡀᚲせࡀ‴᭤ࡋ࡚࠸ࡿሙྜ㸦ࣛ࢘ࣥࢻ࢚ࣥࢻ MLC㸧ࡣࠊ࡛࠶ࡿࠋࡲࡓࠊ඲ᩓ஘ಀᩘࡣ

50%➼⥺㔞⥺ࡀ MLC ඛ➃࡟୍⮴ࡋ࡞࠸ࡇ࡜ࢆ⪃៖ࡤ῝ࡉ 10 cm ࡜ dmax ࡛ࡣ඲ࡃ␗࡞ࡿࡇ࡜࡟ὀពࡍࡿ

ࡋ࡚ MLC ఩⨨ࡢ࢜ࣇࢭࢵࢺ㊥㞳ࢆỴᐃࡍࡿᚲせࡀ

ᚲせࡀ࠶ࡿࠋ ᐃ๓࡟ᚲせ࡞ࢹ࣮ࢱࢆ☜ㄆࡋ࡚࠾ࡃ

࠶ࡿ

141

ࠋ༙ᙳ㒊ࢆ㝖ࡃୖグࡢࣃ࣓࣮ࣛࢱࡣ඲࡚ࣇ࢕

࣒ࣝࢆ⏝࠸ࡓ⥺㔞ᐃ࡟ࡼࡗ࡚ྲྀᚓࡋ࡞ࡅࢀࡤ࡞

ࡽ࡞࠸ࠋMLC 㛫㝽㸦inter-leaf㸧࡜ MLC ୰㸦intra-leaf㸧ᐃ῝࡛ኚ໬ࡋࠊ౛࠼ࡇ࡜ࡀ㔜せ࡛࠶ࡿࠋ

IV.C.1.a.

ᐃࡢ₃ὤ⥺㔞ࡣ㧗࠸ゎീᗘࢆࡶࡘࣇ࢕࣒ࣝ࠿ EPID ࡛

Table I ࡟♧ࡉࢀࡿࡼ࠺࡟ࠊฟຊಀᩘࡣᇶ‽Ⅼ㸦౛ࠊᐃ࡛ࡁࡿࠋࣂࢵࢡ࢔ࢵࣉ⏝ࡢ jaw ࢆక࠺ MLC ࡛

10 cm ࡲࡓࡣ dmax㸧ࠊSSD ࡲࡓࡣ SAD=100 cm ࡟࠾࠸ࡣࠊjaw ࢆ᱁⣡ࡋࡓ≧ែ࡛ྲྀᚓࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋ

࡚ྛ↷ᑕ㔝ࢧ࢖ࢬ࡛

ගᏛ⃰ᗘ࡜⥺㔞ࡢ㛵ಀࢆᚓࡿࡓࡵࠊࣜࣇ࢓ࣞࣥࢫࣇ

㟁㞳⟽ࡢᰯṇ࡜ྠࡌ᪉ἲ㸦SSD ἲࡲࡓࡣ SAD ἲ㸧࢕࣒ࣝࡣᇶ‽῝࡛↷ᑕࡍ࡭ࡁ࡛࠶ࡿࠋࡑࡢ௚ࡢ jaw࡛ฟຊಀᩘࡢ

ࢆ඲㛤ࡋ MLC ࡢࡳ඲㛢ࡋࠊ඲࡚ࡢ MLC ࡀྵࡲࢀࡿ

ࡣࠊᑠ↷ᑕ㔝ࡢฟຊಀᩘࡀᚲせ࡛࠶ࡿࡓࡵᑠᆺ㟁㞳኱ࡁ࠸ࢧ࢖ࢬࡢࣇ࢕࣒ࣝࢆ⏝࠸࡚↷ᑕࡍࡿࠋMLC⟽ࢆ⏝࠸ࡿࠋ㟁㞳⟽ࡢయ✚ᖹᆒຠᯝࢆ㑊ࡅࡿࡓࡵࠊ

↷ᑕ㔝ࢧ࢖ࢬ࡜ẚ㍑ࡋ࡚ࣇ࢕࣒ࣝࡀᑠࡉ࠸࡜ࡁࡣ

㟁㞳⟽ࢧ࢖ࢬࡣ᭱ᑠ↷ᑕ㔝࡜ẚ㍑ࡋ࡚ᑡ࡞ࡃ࡜ࡶ

▷࠸ SSD ࡛ᐃࡍࡿࠋࡇࢀࡣᇶ‽↷ᑕࡢ 10~20 ಸᚲ㸦┤ᚄࡲࡓࡣ㛗ࡉࡢ㸧ྛഃ㠃࡛ 0.5 cm ࡣᑠࡉࡃ࡞ࡅ

せ࡜࡞ࡿ MU ࢆపῶࡍࡿࡇ࡜࡟ࡶᙺ❧ࡘࠋMLC 㛫ࢀࡤ࡞ࡽ࡞࠸ࠋࡇࢀࡽᑠᆺ㟁㞳⟽࡛ᚓࡓࢹ࣮ࢱࡣẚ㝽࡜ MLC ୰ࡢ₃ὤ⥺㔞ࢆྲྀᚓࡍࡿࡓࡵࠊࣇ࢕࣒ࣝ

㍑ⓗ኱ࡁ࠸↷ᑕ㔝࡛኱ࡁ࠸ࢧ࢖ࢬࡢ㟁㞳⟽࡛ࡣ⌧ീᚋ࡟ࢫ࢟ࣕࣥࡋࠊගᏛ⃰ᗘࢆ⥺㔞࡟ኚ᥮ࡍࡿ

ࡋࡓࢹ࣮ࢱ࡜ẚ㍑ࡋࠊ↷ᑕ㔝࡟ᑐࡍࡿ Scp ᭤⥺ࡀⰋᚲせࡀ࠶ࡿࠋࡉࡽ࡟ࠊྲྀᚓࡋࡓ MLC ₃ὤ⥺㔞ࡣ࣓ዲ࡟୍⮴ࡋࠊࢫ࣒࣮ࢬ࡟ࡘ࡞ࡀࡿࡇ࡜ࢆ☜ㄆࡍࡿࡇ࣮࣮࢝ࡈ࡜࡟ᩥ⊩್࡜ẚ㍑ࡍࡿᚲせࡀ࠶ࡿ150

ࠋᐃࡍࡿࠋ⌮᝿ⓗ࡟ࡣࠊࣔࢽࢱ

ᐃࢆ⾜࠺ࡇ࡜ࡀᮃࡲࡋ࠸ࠋIMRT ࡛ᐃ࡜ࡀᮃࡲࡋ࠸ࠋࡇࡢሙྜࠊᑠᆺ㟁㞳⟽ࡣᇶ‽࡜࡞ࡿ↷ᑕ㔝 10 × 10 cm2 ࡛㢧ⴭ࡟ࢫࢸ࣒ຠᯝࡸࢣ࣮ࣈࣝ

IV.C. ගᏊ⥺࣏࢖ࣥࢺ⥺㔞ࢹ࣮ࢱྛ TPS ࡛ᚲせ࡞ࢹ࣮ࢱࡣᵝࠎ࡛࠶ࡿࠋࡋ࠿ࡋࠊᑡ

42↷ᑕࡢᙳ㡪ࢆ♧ࡍྍ⬟ᛶࡀ࠶ࡿࠋࡲࡓࠊ3 × 3 cm2 ௨ୗ࡛ࡣ㟁㞳⟽ࡢㄞࡳ್࡟య✚ᖹᆒຠᯝࡀ⏕ࡌࡿྍ

IV. 光子線のビームデータ

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)⬟ᛶࡀ࠶ࡾࠊタ⨨⢭ᗘ࡜⥺㔞ࣉࣟࣇ࢓࢖ࣝ࡟౫Ꮡࡋ
࡚ 5-10%⛬ᗘప࠸್ࢆ♧ࡍሙྜࡀ࠶ࡿ

151-153ࠋࣥࢺ࣒࡛⏕ࡌࡓᩓ஘⥺࡟ࡼࡿ⾪✺࣮࣐࢝ࡣྵࡲ࡞
࠸ࡇ࡜࡟ὀពࡀᚲせ࡛࠶ࡿࠋᐇ㦂ⓗ࡟ࠊSc ࡣΰධ㟁Ꮚࢆ᤼㝖ࡍࡿ༑ศ࡞ཌࡉࡢ

IV.C.1.b. ࣔࣥࢸ࢝ࣝࣟἲ࡟ࡼࡿ࢔ࣉ࣮ࣟࢳ

࣑ࢽࣇ࢓ࣥࢺ࣒ࢆ⏝࠸࡚ࠊ㟁㞳⟽࡛ᐃࡋࡓ㟁Ⲵࡢ

32ࣔࣥࢸ࢝ࣝࣟἲࡣᨺᑕ⥺἞⒪࡟㛵ࡍࡿ≀⌮ⓗ࡞ẚ࠿ࡽồࡵࡿ ࠋ࣑ࢽࣇ࢓ࣥࢺ࣒ࡢഃ᪉ྥࡢࢧ࢖ࢬ

ࣉࣟࢭࢫࢆṇ☜࡟ࣔࢹࣝ໬ࡍࡿࡇ࡜ࡀ࡛ࡁࠊ࡝ࢇ࡞

ࡣ᳨ฟჾ఩⨨࡛ഃ᪉㟁Ꮚᖹ⾮ࡀᡂ❧ࡋࠊྠ᫬࡟ഃ᪉

࡟」㞧࡞ࢪ࣓࢜ࢺ࡛ࣜ࠶ࡗ࡚ࡶຠᯝⓗ࡛࠶ࡿࡇ࡜

࠿ࡽࡢΰධ㟁Ꮚࢆྲྀࡾ㝖ࡃࢧ࢖ࢬ࡜ࡍ࡭ࡁ࡛࠶ࡿࠋ

154-156ࠋཎ⌮ⓗ࡟ࡣࠊPhase-spaceࡲࡓࠊ࣑ࢽࣇ࢓ࣥࢺ࣒ࡢ⤌ᡂࡣៅ㔜࡟㑅ᢥࡋ࡞ࡅࢀ

ࢹ࣮ࢱ㸦⢏Ꮚ᝟ሗࢹ࣮ࢱ㸧ࢆ฼⏝ࡋࠊ㐺ษ࡞࣋ࣥࢳ

ࡤ࡞ࡽࡎࠊc ࡜ cref 㛫ࡢࢫ࣌ࢡࢺࣝࡢ㐪࠸࡟ࡼࡗ࡚≀࣐࣮ࢡࢸࢫࢺࢆ⾜࠺ࡇ࡜࡟ࡼࡗ࡚࡯࡜ࢇ࡝඲࡚ࡢ㉁࡟౫Ꮡࡋࡓ᭷ព࡞Ỉ୰࣮࣐࢝ẚࡢᕪࢆ⏕ࡌࡉࡏ≧ἣ࡛ṇ☜࡞⥺㔞ィ⟬ࡀྍ⬟࡛࠶ࡿࠋヲ⣽࡞ຍ㏿ჾ࡞࠸ࡇ࡜ࡀ㔜せ࡛࠶ࡿࠋࡋ࠿ࡋࠊ⥺㉁ࡀᇶ‽᮲௳࠿࣊ࢵࢻࢪ࣓࢜ࢺࣜࢆ⏝࠸ࡓࢩ࣑࣮ࣗࣞࢩࣙࣥ࡟ࡼ

ࡽ␗࡞ࡿ᮲௳ୗ㸦౛ࠊ≀⌮࢙࢘ࢵࢪࡢ౑⏝㸧࡛ࡣࠊࡗ࡚ࠊࣔࣥࢸ࢝ࣝࣟἲࡣຍ㏿ჾ࣊ࢵࢻ㒊ࡢྛᵓᡂせSc ࡣ࢚ࢿࣝࢠ࣮ࣇ࢚ࣝࣥࢫẚࡢホ౯್࡛࠶ࡾࠊ⾪✺⣲࡛⏕ࡌࡿ⢏Ꮚ᝟ሗࢆṇ☜࡟Ỵᐃ࡛ࡁࡿࡓࡵࠊࣅ࣮

࣮࣐࢝࡜ࡀド᫂ࡉࢀ࡚࠸ࡿ

࣒ࡢ≉ᛶࢆ᫂ࡽ࠿࡟ࡍࡿࡇ࡜ࡀྍ⬟࡛࠶ࡿ

157, 159

ࠋ≉࡟ࠊࣔࣥࢸ࢝ࣝࣟィ⟬ࡣࠊ(1) ┦ᑐᩓ஘ಀᩘࢆỴᐃ῝ࡲ࡛ࡢῶᙅ࡟ࡼࡗ࡚ኚ໬ࡍࡿࡇ࡜

࡟ὀពࡀᚲせ࡛࠶ࡿࠋ័⩦ⓗ࡟ࠊSc ࡣࣅࣝࢻ࢔ࢵࣉ࢟ࣕࢵࣉࢆ௜ࡅࡓ㟁ᐃࡍࡿࡇ࡜ࠊ(2) ᩓ஘ಀᩘࡢྛᵓᡂᡂศࢆศᯒࡍࡿ

㞳⟽ࢆ⏝࠸࡚

ࡇ࡜ࠊ(3) ᩓ஘ಀᩘࡢ

࢔ࢵࣉ࢟ࣕࢵࣉࡢ㑅ᢥࡣ㠀ᖖ࡟㔜せ࡛ࠊ࢟ࣕࢵࣉཌ

ᐃࡢࡓࡵࡢ᪂ࡋ࠸ᡭἲࢆ⪃᱌ࡍࡿࡇ࡜ࠊ࡛⏝࠸ࡽࢀ࡚ࡁࡓ

10, 11, 13

ࠋ౛࠼ࡤࠊࣔ

ᐃࡍࡿሙྜࡀ࠶ࡿࠋࡇࡇ࡛ࠊࣅࣝࢻ

ࡣ㐣ᑠ࡛࠶ࡿࡼࡾࡣ㐣኱࡛࠶ࡿ᪉ࡀⰋ࠸ࠋ࢟ࣕࢵࣉ

ࣥࢸ࢝ࣝࣟィ⟬ࡣᑠ↷ᑕ㔝࡛ࢥ࣓࣮ࣜࢱ㸦jaw ࡜ࡢཌࡉࡀ୙༑ศ࡞ሙྜࠊ㟁㞳⟽ࡢᛂ⟅ࡣගᏊ࡜࢟ࣕ

MLC ࡞࡝㸧࠿ࡽࡢᩓ஘⥺ࡢᐤ୚ࡀ㢧ⴭ࡛࠶ࡿࡇ࡜

ࢵࣉࡢ┦஫స⏝࡛⏕ࡌࡓ㟁Ꮚࡢࡳ࡛ࡣ࡞ࡃࠊࣅ࣮࣒

ࢆ♧ࡋ࡚࠸ࡿ

160-162ࠋࣔࣥࢸ࢝ࣝࣟἲࡣᐃࡢ᳨ド୰ࡢΰධ㟁Ꮚࡶྵࡴࡓࡵㄗᕪࡢཎᅉ࡜࡞ࡿࠋTG-74

13, 153, 163,ࢆཧ↷ࡋࠊ㐺ษ࡞ࢧ࢖ࢬࡢࣅࣝࢻ࢔ࢵࣉ࢟ࣕࢵࣉࢆ

ࡸᑠ↷ᑕ㔝ࡢࢹ࣮ࢱసᡂ࡛⏝࠸ࡽࢀ࡚࠸ࡿ
164ࠋ

㑅ᢥࡍࡿᚲせࡀ࠶ࡿࠋ࢟ࣕࢵࣉࡢཌࡉࡀ୙༑ศ࡞ሙ
ྜࡣ↷ᑕ㔝ࢧ࢖ࢬ࡟ᑐࡍࡿ✵୰ฟຊಀᩘ㸦Sc㸧ࡀⴭ

IV.C.2. ✵୰ฟຊಀᩘ

ࡋࡃኚ໬ࡍࡿࡓࡵࠊࡑࡢ⤖ᯝ࡜ࡋ࡚ࣇ࢓ࣥࢺ࣒ᩓ஘

Sc ࡣ✵୰ฟຊಀᩘ㸦in-air output factor

165

㸧ࠊࢥ࣓ࣜ

ಀᩘ㸦Sp㸧ࡣ↷ᑕ㔝࡟ᑐࡋ࡚ᖹᆠ࡜࡞ࡿࠋᑠ↷ᑕ㔝࣮ࢱᩓ஘ಀᩘ㸦collimator-scatter factor 㸧ࠊ࣊ࢵࢻᩓ

㸦 4 × 4 cm2㸧࡛ྠࡌ࣑ࢽࣇ࢓ࣥࢺ࣒ࢆ⏝࠸ࡿሙྜ஘ಀᩘ㸦head scatter factor166, 167㸧࡜ࡶ࠸ࢃࢀࡿࠋᚋ 2ࡣ㊥㞳ࢆ㞳ࡋ࡚

⪅ࡣฟຊಀᩘࡢ 1 せ⣲࡛࠶ࡿࡇ࡜ࡀᙉㄪࡉࢀࡿሙྜ

࡛ྲྀᚓࡋࡓ 2 ࡘࡢ Sc ࢆ⤫ྜ࡛ࡁࡿࡼ࠺࡟ࠊᘏ㛗㊥㞳࡟⏝࠸ࡿࠋTG-74㸦Ref. 20㸧࡛ࡣ✵୰ฟຊಀᩘ Sc ࡢ࡛ࡶ 10 × 10 cm2 ࡢฟຊಀᩘࢆ

ヲ⣽ࡀ♧ࡉࢀ࡚࠾ࡾࠊ௵ពࡢ↷ᑕ㔝࡜ᇶ‽↷ᑕ㔝ࡢࠊ࡛࠶ࡿࠋTG-74 ࡛ࡣ඲࡚ࡢ Sc ࢆྠࡌ SSD ࡛༢఩ MU タᐃ್࠶ࡓࡾࡢ✵Ẽ୰࡟࠾ࡅࡿỈࡢ୍ḟ⾪ࡿࡓࡵࠊ㧗ཎᏊ␒ྕࡢ࣑ࢽࣇ࢓ࣥࢺ࣒ࡢ౑⏝ࢆ᥎ዡ✺࣮࣐࢝; Kp ࡢẚ࡜ࡋ࡚ᐃ⩏ࡉࢀࡿࠋࡋ࡚࠸ࡿࠋ ᐃྍ⬟࡞᭱ᑠ↷ᑕ㔝ࡣࠊ࣑ࢽࣇ࢓ࣥࢺ

88

Sc

K p c; z ref M
K p cref ; z ref Mᐃ࡛ࡁࡿࠋࡇࡢሙྜࠊ␗࡞ࡿ SSDᐃࡍࡿࡇ࡜ࡀ㔜せᐃࡍ࣒ࡢእ࿘࠿ࡽᑡ࡞ࡃ࡜ࡶ 1 cm ࡢ⠊ᅖࡀ↷ᑕࡉࢀࡿ,(4)

ࡇࡇ࡛ c ࡣ௵ពࡢࢥ࣓࣮ࣜࢱࢭࢵࢺࠊcref ࡣᇶ‽ࡢࢥ
2᮲௳࡛࠶ࡿࠋ
IV.C.3. ࣇ࢓ࣥࢺ࣒ᩓ஘ಀᩘ ࣓࣮ࣜࢱࢭࢵࢺࢆ♧ࡋࠊ㏻ᖖࡣ 10 × 10 cm ࡛࠶ࡿࠋࣇ࢓ࣥࢺ࣒ᩓ஘ಀᩘ㸦Sp㸧ࡣࣇ࢓ࣥࢺ࣒୰ࡢᇶ‽ࡉࡽ࡟ࠊzref ࡣᇶ‽ࡢ⥺※-᳨ฟჾ㛫㊥㞳࡛࠶ࡾࠊ㏻

῝ dref ࡟࠾ࡅࡿ↷ᑕ㔝ࢧ࢖ࢬ s ࡜ᇶ‽↷ᑕ㔝 sref ࡜ࡢᖖࡣ 100 cm ࡛࠶ࡿࠋࡲࡓࠊ୍ḟ⾪✺࣮࣐࢝ࡣ἞⒪ᩓ஘ಀᩘẚ࡜ࡋ࡚ᐃ⩏ࡉࢀࡿࠋ࣊ࢵࢻ࡛⏕ࡌࡓ඲࡚ࡢᩓ஘⥺ࢆྵࡴࡀࠊ࿘ᅖࡢࣇ࢓

43

医学物理 第 33 巻 第 1 号

S p (s)IV. 光子線のビームデータ

SF ( s, d ref )SF ( s ref , d ref )(5)࡝ 2 ✀㢮ࡢタ⨨᪉ἲ࡛≀⌮࢙࢘ࢵࢪࢆ฼⏝࡛ࡁࡿሙྜࠊࢹ࣮ࢱࡢ᳨ドࡀᚲせ࡛࠶ࡿࠋࡇࢀࡣ↷ᑕ㔝࡜῝

ࡇࡇ࡛ SF ࡣࠊྠࡌ↷ᑕ㔝ࢧ࢖ࢬ࡜῝ࡉ࡛ࠊྠࡌ఩

ࡉ࡟ࡘ࠸࡚ᩘⅬ࡛☜ㄆࡍࢀࡤⰋࡃࠊCheng ࡽ 175 ࡣ⨨࡟࠾ࡅࡿࠊ୍ḟ⥺ࡢ⥺㔞㸦Dp㸧࡟ᑐࡍࡿỈ୰ࡢ඲lower ࡜ upper ࡢ࢙࢘ࢵࢪಀᩘࡣ࡯ࡰ୍⮴ࡍࡿࡇ࡜⥺㔞㸦D㸧ࡢẚ࡛࠶ࡿࠋࡲࡓࠊࣇ࢓ࣥࢺ࣒ᩓ஘ಀᩘ

ࢆ♧ࡋ࡚࠸ࡿࠋ

ࡣ㏆ఝⓗ࡟ḟᘧ࡛Ỵᐃ࡛ࡁࡿࠋ

S p (s) |

S cp

(6)

Sc

IV.C.4.b. ࢯࣇࢺ࢙࢘ࢵࢪ
ࢯࣇࢺ࢙࢘ࢵࢪࡣ࢚ࣞࢡࢺࣟࢽࢵࢡ࢙࢘ࢵࢪࡲ

ᘧ(6)ࡢ Sp ࡣࠊᘧ(3)࡜ᘧ(4)࡛ᐃ⩏ࡉࢀࡿ Scp ࡜ Sp ࢆࡓࡣ㠀≀⌮࢙࢘ࢵࢪ࡜࿧ࡤࢀࠊၟᶆ࡛ࡣࢲ࢖ࢼ࣑ࢵ

⏝࠸࡚ྲྀᚓࡍࡿࠋ୍ḟ⥺ࡢ྾཰⥺㔞࡜⾪✺࣮࣐࢝ࡢࢡ࢙࢘ࢵࢪࡲࡓࡣࣂ࣮ࢳ࢙ࣕࣝ࢘ࢵࢪ࡜ࡋ࡚▱ࡽẚ ȕp ࢆ⏝࠸࡚ࠊ୍ḟ⥺㔞࡜୍ḟỈ⾪✺࣮࣐࢝ࡢ㛵ಀࢀ࡚࠸ࡿࠋࡇࢀࡽࡣ〇㐀ᴗ⪅࡟ࡼࡗ࡚ືసࡀ␗࡞ࡿࠋ

ࢆ⾲ࡏࡿ㸦Dp=ȕpKp㸧ࠋᘧ(6)ࡣࠊ୍ḟ⥺ࡢ⥺㔞-࣮࢝

Varian ♫ࡣ࢚ࣥࣁࣥࢫࢻࢲ࢖ࢼ࣑ࢵࢡ࢙࢘ࢵࢪ

࣐ẚࡀ↷ᑕ㔝ࢧ࢖ࢬ࡟౫Ꮡࡋ࡞࠸ሙྜ

㸦Enhanced dynamic wedge; EDW㸧ࠊSiemens ♫ࡣࣂ㹙ȕp(s)=ȕp(sref) 㹛ࠊཝᐦ࡟ᡂ❧ࡍࡿࠋ࣮ࢳ࢙ࣕࣝ࢘ࢵࢪ㸦Virtual wedge; VW㸧ࢆ᥇⏝ࡋ࡚
࠸ࡿ 176-179ࠋ୧〇㐀ᴗ⪅࡜ࡶ୍᪉ࡢ Y-jaw ࢆ㥑ືࡋ࡚

IV.C.4. ࢙࢘ࢵࢪಀᩘ

⥺㔞໙㓄ࢆ⏕ࡌࡉࡏࠊ௚᪉ࡢ Y-jaw ࡣ㟼Ṇࡉࡏ࡚࠸

IV.C.4.a. ≀⌮࢙࢘ࢵࢪࡿࠋEDW ࡜ VW ࡢ୺࡞㐪࠸ࡣࠊEDW ࡣ jaw ࡢ⛣ື㏻ᖖࠊ࢙࢘ࢵࢪಀᩘࡣ࢙࢘ࢵࢪゅᗘࠊ῝ࡉࠊගᏊ࢚ࢿࣝࢠ࣮࠾ࡼࡧ↷ᑕ㔝ࢧ࢖ࢬ࡟౫Ꮡࡍࡿ

168-173ࠋ≀⌮࢙࢘ࢵࢪࡢಀᩘࡣᇶ‽῝㸦10 cm ࡲࡓࡣ dmax㸧ࠊ
SSD=100 cm ࡟࠾࠸࡚␗࡞ࡿ↷ᑕ㔝࡛㏿ᗘ࡜⥺㔞⋡ࡀኚ໬ࡍࡿࡢ࡟ᑐࡋࠊVW ࡣ jaw ࡢ⛣ື㏿ᗘࡀ୍ᐃ࡛ゎᯒ㛵ᩘ࡟ᚑࡗ࡚⥺㔞⋡ࢆኚ໬ࡉ
ࡏࡿⅬ࡛࠶ࡿࠋ

ᐃࡍࡿࠋຍࢯࣇࢺ࢙࢘ࢵࢪࡢ࢙࢘ࢵࢪಀᩘࡣ≀⌮࢙࢘ࢵࢪ㏿ჾࡢ୰࡟ࡣ኱↷ᑕ㔝࡛࢙࢘ࢵࢪಀᩘࡀ↷ᑕ㔝࡟ࡢಀᩘ࡜ࡣ඲ࡃ␗࡞ࡿࠋEDW ࡢ࢙࢘ࢵࢪಀᩘࡣ࢜

ᙉࡃᙳ㡪ࡉࢀࡿࡶࡢࡀ࠶ࡾࠊࡑࡢሙྜᗈ⠊ᅖࡢ↷ᑕ࣮ࣉࣥ↷ᑕ㔝ࡢ୰ᚰ࡛῝ࡉ 10 cm ࡟ࡘ࠸࡚ᐃ⩏ࡉࢀࠊ

170, 171, 174ࠋ࡯࡜↷ᑕ㔝ࢧ࢖ࢬ࡜࢙࢘ࢵࢪゅᗘ࡟౫Ꮡࡋࠊ≀⌮࢙࢘ࢵࢇ࡝ࡢ TPS ࡛ࡣࠊࡑࢀࡒࢀࡢ↷ᑕ㔝࡟ࡘ࠸࡚࢙࢘ࢵ

ࢪ࡜ẚ㍑ࡋ࡚ 10%-30%㧗࠸ᩘ್ࢆ♧ࡍࠋ⥺㉁ࡀኚ໬

ࢪಀᩘࢆỴᐃࡍࡿࡇ࡜ࡀ࡛ࡁࡿࠋ

ࡋ࡞࠸ࡓࡵ EDW ࡢ࢙࢘ࢵࢪಀᩘࡣ῝ࡉ࡟ᙳ㡪ࡉࢀ㔝⠊ᅖ࡟ᑐࡋ࡚

ᐃࡍࡿ࡭ࡁ࡛࠶ࡿ

᳨ฟჾࢆࣅ࣮࣒୰ᚰ࡟ṇ☜࡟タ⨨ࡍࡿࡇ࡜ࡀ㔜࡞࠸ࡇ࡜ࡀሗ࿌ࡉࢀ࡚࠸ࡿ 175, 180ࠋ୍᪉࡛ Siemens

せ࡛࠶ࡿࡓࡵࠊ᳨ฟჾࡢ㛗㍈ࢆ㠀໙㓄᪉ྥ࡟㓄⨨ࡋࠊ♫ࡢ VW ࡛ࡣࠊ࢙࢘ࢵࢪಀᩘࡣ↷ᑕ㔝࠾ࡼࡧ࢙࢘ࢵ

60°࢙࢘ࢵࢪࢆ⏝࠸࡚ᑐྥࡍࡿ 2 ࡘࡢࢥ࣓࣮ࣜࢱゅࢪゅᗘ࡟࡯࡜ࢇ࡝౫Ꮡࡏࡎࠊ1.0% ± 2%ࡢ⠊ᅖࡢ್ᗘ㸦90°࡜ 270°࡞࡝㸧࡛ㄞࡳ್ࡢ୍⮴ࢆ☜ㄆࡍࡿࠋࢆ♧ࡍࠋ࢙࢘ࢵࢪಀᩘࡣࠊ␗࡞ࡿ↷ᑕ㔝ࢧ࢖ࢬ࡟ࡘ

᳨ฟჾࡀࣅ࣮࣒୰ᚰ࡟㓄⨨ࡉࢀ࡚࠸ࡿࡇ࡜ࢆ☜ㄆ࠸࡚ SSD/SAD=100 cm ࡛࣋ࣥࢲ࣮࡟ࡼࡗ࡚ᣦᐃࡉ

ࡋࡓᚋࠊ୍᪉ࡢ࢙࢘ࢵࢪ᪉ྥ࡜ 180 ᗘ཯ᑐ࡟ᤄධࡋࢀࡓᇶ‽῝㸦10 cm ࡲࡓࡣ dmax㸧࡛ࡓ࢙࢘ࢵࢪ᪉ྥ࡛

ᐃࡍࡿࠋ࢙࢘ࢵࢪಀᩘࡣ୍ᐃࡢ

࡟ࠊ࢙࢘ࢵࢪಀᩘࡣᅛᐃ jaw ࡢ఩⨨ࡼࡾ㥑ື jaw ࡢࢥ࣓࣮ࣜࢱゅᗘ࡛ᚓࡓ 2 ࡘࡢ࢙࢘ࢵࢪ᪉ྥࡢㄞࡳ್

ࢧ࢖ࢬ࡟౫Ꮡࡍࡿࡓࡵࠊ㛗᪉ᙧ↷ᑕ㔝ࡢ࢙࢘ࢵࢪಀ

ࡢᖹᆒࢆ࣮࢜ࣉࣥ↷ᑕ㔝ࡢㄞࡳ್࡛㝖ࡋ࡚ᚓࡿࠋ࢘

ᩘࢆ㏣ຍࡋ࡚

࢙ࢵࢪಀᩘࡣྲྀᚓࡍࡿ῝ࡉ࡟ࡼࡗ࡚㢧ⴭ࡟␗࡞ࡿ

♫ࡢ EDW ࡢ 10 × 20 cm2 ࡢ࢙࢘ࢵࢪಀᩘࡣ 10 × 10

ሙྜࡀ࠶ࡿࠋᇶᮏⓗ࡟ࠊ࢙࢘ࢵࢪಀᩘࡢ

ᐃ῝ࡣ TPS࡟ࡼࡗ࡚ᣦᐃࡉࢀ࡚࠸ࡿࠋࡋ࠿ࡋࠊᡭィ⟬⏝࡟࣮࢜ᐃࡍࡿࠋࡉࡽ

ᐃࡍ࡭ࡁ࡛࠶ࡿࠋ౛࡜ࡋ࡚ࠊVarian

cm2 ࡢ࢙࢘ࢵࢪಀᩘ࡜㠀ᖖ࡟㏆࠸್ࢆ♧ࡋࠊࡇࢀࡣ
≀⌮࢙࢘ࢵࢪ࡛ࡣ⏕ࡌ࡞࠸⌧㇟࡛࠶ࡿࠋ

ࣉࣥ↷ᑕ㔝࡜࢙࢘ࢵࢪ↷ᑕ㔝ࡢ PDD ⾲ࡸ TMR ⾲ࢆูࠎ࡟⏝࠸ࡿሙྜࠊࣅ࣮࣒ࣁ࣮ࢻࢽࣥࢢ⿵ṇࢆ 2 㔜

IV.C.4.c. ࣘࢽࣂ࣮ࢧ࢙ࣝ࢘ࢵࢪ

࡟⾜ࢃ࡞࠸ࡓࡵ࢙࢘ࢵࢪಀᩘࡣ dmax ࡛ྲྀᚓࡍࡿ᪉ࡀ

Elekta ♫ࡢࣜࢽ࢔ࢵࢡ࡛ࡣࠊ␗࡞ࡿ࢙࢘ࢵࢪゅᗘ㐺ษ࡛࠶ࡿࠋVarian ♫ࡢ lower ࡜ upper ࢙࢘ࢵࢪ࡞

ࢆ⏕ᡂࡍࡿࡓࡵࠊ࣮࢜ࣉࣥ↷ᑕ㔝࡜ෆⶶᘧࡢ 60° ≀44V. 電子線

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)⌮࢙࢘ࢵࢪ↷ᑕ㔝ࢆࢯࣇࢺ࢙࢘࢔࡟ࡼࡿไᚚ࡛ྜ

࡭ࡁ࡛࠶ࡿࠋฟຊಀᩘࡣ᳨ฟჾࡢタ⨨⢭ᗘ࡟ᙉࡃᙳ

ᡂࡍࡿᡭἲࢆ᥇⏝ࡋ࡚࠸ࡿࠋ࢙࢘ࢵࢪࡣ࣮ࣔࢱ㥑ື㡪ࡉࢀࡿࡓࡵࠊタ⨨఩⨨ࡢ᳨ドࡣ㔜せ࡛࠶ࡿ 151,202ࠋ࡛↷ᑕ㔝ෆ࡟ฟࡋධࢀࡉࢀࡿࠋࡇࡢࢱ࢖ࣉࡢ࢙࢘ࢵ

ࡇࢀࡣ xy ୧᪉ྥ࡛ࢫ࢟ࣕࣥࡋࠊ᭱኱್ࢆ♧ࡍࡇ࡜ࢪࢩࢫࢸ࣒ࡣෆ㒊࢙࢘ࢵࢪࡲࡓࡣࣘࢽࣂ࣮ࢧࣝ࢘

ࢆ☜ㄆࡍࡿ᪉ἲ࡛⾜࠺ࠋ㏆ᖺࠊࡼࡾ⢭ᗘࡢ㧗࠸᪉ἲ࢙ࢵࢪ࡜ࡋ࡚▱ࡽࢀ࡚࠸ࡿࠋ࢙࢘ࢵࢪಀᩘࡣ TPS ࡛ࡀ Li ࡽ 203 ࡟ࡼࡗ࡚ᥦ᱌ࡉࢀ࡚࠸ࡿࠋᑠ↷ᑕ㔝࡛ࡣᚲせ࡜࡞ࡿᵝࠎ࡞↷ᑕ㔝ࢧ࢖ࢬ࡜῝ࡉ࡛ྲྀᚓࡍࡿ

↷ᑕ㔝ࢧ࢖ࢬࡢഹ࠿࡞ㄗᕪ࡟ࡼࡗ࡚㢧ⴭ࡟ฟຊࡀᚲせࡀ࠶ࡾࠊከࡃࡢᩥ⊩࡛♧ࡉࢀ࡚࠸ࡿ

181-184ࠋኚ໬ࡍࡿࡓࡵࠊᐇ㝿ࡢ↷ᑕ㔝ࢧ࢖ࢬࡶ᳨ドࡍࡿᚲせࡀ࠶ࡿࠋࡋ࠿ࡋࠊഃ᪉㟁Ꮚᖹ⾮ࡀᡂ❧ࡋ࡞࠸᮲௳࡛

IV.C.5. ࢺࣞ࢖ಀᩘ

ࡣṇ☜࡞↷ᑕ㔝ࢧ࢖ࢬࡀᚓࡽࢀ࡞࠸ሙྜࡀ࠶ࡿࠋ≉ࣈࣟࢵࢡࢺࣞ࢖ࠊMLCࠊjaw ࡢ㏱㐣ಀᩘࡣỈ୰ࡢᇶ‽῝㸦10 cm ࡲࡓࡣ dmax㸧࡛࡟ࠊ㟁Ꮚᖹ⾮ᡂ❧᮲௳࡜ẚ㍑ࡋ࡚᭱኱್ࡀ㐣ᑠホ౯ᐃࡉࢀࠊ࣮࢜ࣉࣥ

ࡉࢀࡓሙྜࠊ್༙㸦half-maximum㸧ࡀప⥺㔞ࣞ࣋ࣝ↷ᑕ㔝࡟ᑐࡍࡿࣈࣟࢵࢡࢺࣞ࢖ࠊMLC ࠾ࡼࡧ jaw ┤ࡼࡾ࡟ࢩࣇࢺࡍࡿ㸦ࡘࡲࡾࠊ⥺㔞ࣉࣟࣇ࢓࢖ࣝࡢእ

ୗ࡛ࡢㄞࡳ್ࡢẚ࡛ᐃ⩏ࡉࢀࡿࠋMLC ࡸ jaw ࡢ㏱㐣ഃ࡟ࢩࣇࢺࡍࡿ㸧ࡇ࡜࡟ࡼࡗ࡚↷ᑕ㔝ࢧ࢖ࢬࢆ㐣኱ࡣ㠀ᖖ࡟ᑠࡉ࠸ࡓࡵࠊ㟁఩ィ/᳨ฟჾࢩࢫࢸ࣒ࡢ┤⥺ホ౯ࡍࡿࡇ࡜ࡀ࠶ࡾࠊὀពࢆせࡍࡿࠋࡲࡓࠊග↷ᑕࣞࣥࢪ࡟ྵࡲࢀࠊ⤫ィⓗ୙☜࠿ࡉࢆ᤼㝖࡛ࡁࡿࡼ࠺

㔝࡜ࢥ࣓࣮ࣜࢱ⛣ື఩⨨ࢆࡑࢀࡒࢀㄪᩚࡍࡿࡇ࡜

MU ್ࡣ༑ศ࡟኱ࡁࡃタᐃࡍࡿᚲせࡀ࠶ࡿࠋࢺࣞ࢖

࡛ࠊ↷ᑕ㔝➃ࡢ఩⨨ࢆ⟶⌮ࡍࡿᚲせࡀ࠶ࡿࠋ㏱㐣ಀᩘࡣỈࣇ࢓ࣥࢺ࣒࡞ࡋ࡛ࡶ

ᐃࡍࡿࡇ࡜ࡀ
V. 㟁Ꮚ⥺

࡛ࡁࡿࠋ

V.A. 㟁Ꮚ⥺ࢫ࢟ࣕࣥࢹ࣮ࢱ
IV.C.6. ᑠ↷ᑕ㔝࡛ࡢ⪃៖

V.A.1. ῝㒊⥺㔞୍⯡ⓗ࡞ᨺᑕ⥺἞⒪࡛⏝࠸ࡽࢀࡿ↷ᑕ㔝ࡣ 4 × 42

ᐃ2

Followill ࡽ࡟ࡼࡗ࡚♧ࡉࢀ࡚࠸ࡿࡼ࠺࡟ࠊ㟁Ꮚ⥺cm ࠿ࡽ 40 × 40 cm ࡛࠶ࡿࠋࡋ࠿ࡋࠊIMRTࠊSRSࠊࡢ῝㒊⥺㔞≉ᛶࡣࠊ᪋タࡸ⿦⨨ẖ࡟኱ࡁࡃ␗࡞ࡿ 204ࠋ

CyberKnifeࠊGamma Knife ࡞࡝㧗⢭ᗘ࡛≉Ṧ࡞ᨺᑕࡼࡗ࡚ࢥ࣑ࢵࢩࣙࢽࣥࢢ࡛ࡣࠊ⿦⨨ẖ࡟ࣅ࣮࣒ࢹ࣮

⥺἞⒪࡛ࡣᩘ mm ࡢᴟ➃࡟ᑠࡉ࠸↷ᑕ㔝ࢆ౑⏝ࡍࡿࠋࢱࢆᐃࡍࡿࡇ࡜ࡀ᥎ዡࡉࢀࡿࠋ㟁Ꮚ⥺ࡢࣅ࣮࣒ࢹ

ᑠ↷ᑕ㔝ࡢ⥺㔞࣮ࢱᐃ࡟ࡣࠊࢲ࢖࣮࢜ࢻ᳨ฟჾࠊᖹ⾜ᖹᯈᙧ㟁㞳ᐃ࡟㛵ࡍࡿၥ㢟Ⅼࡢヲ⣽࡞ࣜࢫࢺ࡜ᑗ᮶ࡢືྥࡣ Das ࡽ 152 ࡟ࡼࡗ࡚㆟ㄽࡉࢀ࡚࠸

⟽ࠊᣦ㢌ᙧ㟁㞳⟽ࡸࣇ࢕࣒ࣝ࡞࡝ࡀ⏝࠸ࡽࢀࡿࠋ

ࡿࠋ≉࡟ࠊഃ᪉㟁Ꮚᖹ⾮ࡢḞዴ 186ࠊ༙ᙳ㒊࡜᳨ฟჾ

Ⰻ㉁࡞PDDࢆྲྀᚓࡍࡿ࡟ࡣࠊṇ☜࡞ 0 mm῝ࡢỴ

ࢧ࢖ࢬ

152

ࠊ࢚ࢿࣝࢠ࣮ࢫ࣌ࢡࢺࣝࡢኚ໬࡟క࠺⥺㔞ᐃ࡟㛵ಀࡍࡿࣃ࣓࣮ࣛࢱࡸ㜼Ṇ⬟ẚࡢኚ໬
187-189࡞࡝ࠊᑠ↷ᑕ㔝ࡢ⥺㔞࡜ࡍࡿࠋᑠ↷ᑕ㔝ࡢ⥺㔞

163,

ᐃࡀ㔜せ࡛࠶ࡿࠋᣦ㢌ᙧ㟁㞳⟽ࡢᐇຠ୰ᚰࡣࠊᗄఱ
Ꮫⓗ୰ᚰ࠿ࡽ 0.5rcyl⥺※ഃ࡛࠶ࡿ 56, 145 ヂ⪅ὀ 4ࠋ 6

ᐃࡣከࡃࡢ▱㆑ࢆᚲせMeV࡞࡝ࡢప࢚ࢿࣝࢠ࣮㟁Ꮚ⥺ࡢ῝㒊㟁㞳㔞᭤⥺ᐃࡢၥ㢟࡜ഴྥࡣከࡃࡢ

㸦Percentage Depth Ionization, PDI㸧ࢆྲྀᚓࡍࡿࡇ࡜

ⴭ⪅࡟ࡼࡗ࡚㆟ㄽࡉࢀ࡚࠸ࡿ

࡛ࠊ0 mm῝ࡀṇࡋ࠸タᐃ࡛࠶ࡿ࠿☜ㄆ࡛ࡁࡿࠋṇࡋ

11,13,64,66,67,151,152,163,164,187-202

ࠋ࠸PDI᭤⥺ࡣࠊ〇㐀ᴗ⪅࡟࠿࠿ࢃࡽࡎ 6 MeV࡛ࡣᖹᑠᆺ᳨ฟჾ࡟࠾࠸࡚ࡶࠊ࢚ࢿࣝࢠ࣮ࠊ⥺㔞࠾ࡼࡧ

ᆒ 1.1 s 0.2 cmࡢ᭱኱῝㸦dmax㸧࡜࡞ࡿࡣࡎ࡛࠶ࡿࠋ

⥺㔞⋡౫Ꮡᛶࡀᑠࡉ࠸᳨ฟჾࡀᮃࡲࡋ࠸ࠋ࣐࢖ࢡࣟ

ࡇࡢ㟁㞳㔞࡟ࡼࡿdmaxࡀ 0.2 cm௨ୖ␗࡞ࡿ࡜ࠊ0 mm

3ᆺ㟁㞳⟽㸦⣙ 0.01 cm 㸧ࡣᑠ↷ᑕ㔝ࡢ⥺㔞ᐃ࡟᭷ຠ࡛࠶ࡿࡀࠊಙྕ࡟ᑐࡍࡿࣀ࢖ࢬࡢẚ⋡ࡀቑ኱ࡍࡿࡓࡵホ౯ࡀᚲせ࡛࠶ࡿࠋࡉࡽ࡟ࠊSauer ࡽFrancescon ࡽ

153

164

ࡸ

ࡀ♧ࡍࡼ࠺࡟ࠊࡇࢀࡽࡢ᳨ฟჾ࡛ࡣ

ᨐ஘ಀᩘ࡟ࡘ࠸࡚⪃៖ࡍࡿᚲせࡀ࠶ࡿࠋ↷ᑕ㔝୰ᚰ࡛ࡢࢫ࢟ࣕࣥ῝ࡢタᐃࡀㄗࡗ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿࡓࡵࠊ㟁㞳⟽࡜Ỉ㠃ࡢタ⨨ࢆ෌☜ㄆࡍࡿᚲせࡀ࠶ࡿࠋ PDI ᭤⥺ࡣ඲࢚ࢿࣝࢠ࣮ࡢࣜࣇ࢓ࣞࣥࢫ࡜࡞ࡿࢥ
࣮ࣥ㸦10 × 10 cm2 ࡸ 15 × 15 cm2㸧࡛ࠊᐇ⏝㣕⛬㸦Rp㸧
+ 10 cm ࡢ῝ࡉࡲ࡛ 0.1 cm 㛫㝸࡛ᐃࡍࡿ࡭ࡁ࡛࠶

ᐃ࡛ࠊ᳨ฟჾ┤ᚄࡢ⠊ᅖ࡛⥺㔞ࡀ

1%௨ୖኚ໬ࡍࡿሙྜࡣࠊࡼࡾᑠࡉ࠸᳨ฟჾ࡟ኚ᭦ࡍ

ヂ⪅ὀ4rcyl ࡣ㟁㞳✵Ὕࡢ༙ᚄ࡛࠶ࡿࠋ

45

医学物理 第 33 巻 第 1 号

V. 電子線ࡿࠋ㟁Ꮚ⥺ࢹ࣮ࢱࡢࢥ࣑ࢵࢩࣙࢽࣥࢢࡣࠊ10 × 10 cm2
ࡲࡓࡣ 15 × 15 cm2 ࡀࣜࣇ࢓ࣞࣥࢫࡢࢥ࣮ࣥ࡜ࡋ࡚
౑⏝ࡉࢀࡿࠋࣜࣇ࢓ࣞࣥࢫ࡜࡞ࡿࢥ࣮ࣥࢆ౑⏝ࡋࡓ඲࢚ࢿࣝࢠ࣮ࡢ PDI ᭤⥺࠿ࡽࠊࣉࣟࣇ࢓࢖ࣝࢫ࢟ࣕࣥࢆࡍࡿ῝ᗘ dmax, d90, d80, d70, d60, d50, d40, d30, d20, ࠾ࡼࡧ Rp ࡀỴᐃࡉࢀࡿࠋཝᐦ࡟ゝ࠼ࡤࠊRp ࡣࣅ࣮࣒ࢆ⿵ṇࡋࡓ῝㒊㔞ⓒศ⋡㸦PDD㸧࠿ࡽồࡵࡽࢀࡿ࡭
ࡁ࡛࠶ࡿࡀࠊSSD 100 cm ࡛ࡣࠊ῝㒊⥺㔞࡟ࡼࡿ Rp࡜῝㒊㟁㞳㔞࡟ࡼࡿ Rp ࡢ┦㐪ࡣࢃࡎ࠿࡛࠶ࡿࠋ 㟁㞳⟽࡟ࡼࡿỈ୰࡛ࡢ PDI ᭤⥺ࡣࠊ㐺ษ࡞ኚ఩⿵
ṇಀᩘ࡜Ỉ㸭✵Ẽࡢᖹᆒไ㝈㉁㔞⾪✺㜼Ṇ⬟ẚࢆ

FIG. 12. Effect of water ripple on low energy electron beam depth౑⏝ࡋ࡚ࠊ῝㒊⥺㔞᭤⥺࡟ኚ᥮ࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋ

dose.

࡯ࡰ඲࡚ࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡟ࠊ㟁㞳㔞ࢆ⥺㔞࡟ኚ᥮ࡍࡿࡓࡵࡢࣉࣟࢢ࣒ࣛࡀᐇ⿦ࡉࢀ࡚࠸ࡿࠋࡇ
ࢀࡽࢆ౑⏝ࡍࡿሙྜࡣࠊࣜࣇ࢓ࣞࣥࢫࢹ࣮ࢱࢆᇶ࡟ࠊ

ືᨺᑕ⥺ᡂศࡢホ౯ࡣṇ☜࡛ࡣ࡞࠸ヂ⪅ὀ 6ࠋ

ྛ῝ࡉ࡛ኚ᥮⢭ᗘࢆ᳨ドࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸
22,56,88,205

V.A.2. ࣉࣟࣇ࢓࢖ࣝ

ࠋ

III❶࡛グ㏙ࡋࡓࢫ࢟ࣕࣥ㏿ᗘࠊ㐜ᘏ᫬㛫ࡸࢧࣥࣉ ከࡃࡢ TPS ࡛ࡣ୍⯡ⓗ࡟ࠊdmaxࠊd90ࠊd70ࠊd50ࠊd30

ࣜࣥࢢ᫬㛫ࡣࠊ ᐃࢹ࣮ࢱࡢ㉁࡟ᙳ㡪ࢆ୚࠼ࡿࡓࡵࠊ

࡜ d10㸦ࡘࡲࡾࠊ100%ࠊ90%ࠊ70%ࠊ50%ࠊ30%࡜ 10%ៅ㔜࡟タᐃࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋFig. 12 ࡟ỈࡢἼ❧⥺㔞ࡢ῝ࡉ㸧࡞࡝ࡢ῝ࡉ࡛ࡢ⥺㔞ࣉࣟࣇ࢓࢖ࣝࢆᚲ

ࡕ࡟ࡼࡿPDD᭤⥺࡬ࡢᙳ㡪ࢆ♧ࡍࠋࡇࡢࡼ࠺࡞ሙྜ

せ࡜ࡍࡿࠋࡓࡔࡋࠊ⥺㔞ࣉࣟࣇ࢓࢖ࣝࢆྲྀᚓࡋ࡞ࡅ

ࡣࠊࢫ࢟ࣕࣥࣃ࣓࣮ࣛࢱࡢ෌タᐃࡀᚲせ࡛࠶ࡿࠋ㟁ࢀࡤ࡞ࡽ࡞࠸῝ࡉࡣࠊTPS ࡢ௙ᵝ࡟ࡼࡗ࡚␗࡞ࡿࠋ

Ꮚ⥺ࡢࢫ࡛࢟ࣕࣥ⌮᝿ⓗ࡞≉࡟ప࢚ࢿࣝࢠ࣮㟁Ꮚ⥺࡛ࡣࠊdmax ࡼࡾ῝࠸఩⨨࡛ᐃჾࡣࠊ✵㛫ศゎ⬟ࡢ㧗࠸ᑠᆺࡢ㟁Ꮚ⥺⏝ࢲ࢖࣮࢜ࢻ᳨ฟჾ࡛࠶ࡿࠋࡑࡢ

ࡢࣉࣟࣇ࢓࢖ࣝࡢ

⌮⏤ࡣࠊ(1) 㟁㞳㔞࠿ࡽ⥺㔞࡟ኚ᥮ࡍࡿᚲせࡀ↓࠸ヂ࢓࢖ࣝᙧ≧ࡀ㢧ⴭ࡟㠀ᑐ⛠࡛࠶ࢀࡤࠊࢫ࢟ࣕࢽࣥࢢ

ᐃⅬࡢኚ఩ࢆ⾜࠺ᚲせࡀ↓࠸ࠋࡓࡔࡋࠊ

ࢱࣥࢡࡸࢫ࢟ࣕࣥ࢔࣮࣒ࡢỈᖹࠊ࢞ࣥࢺࣜゅᗘ࡞࡝㜵Ỉࢥ࣮ࢸ࢕ࣥࢢ㸦㏻ᖖ~0.2 mm㸧ࡀ᪋ࡉࢀ࡚࠸ࡿ

ࡢ෌☜ㄆࡀᚲせ࡛࠶ࡿࠋప࢚ࢿࣝࢠ࣮㟁Ꮚ⥺ࡢ῝࠸ࢲ࢖࣮࢜ࢻ᳨ฟჾ࡟ࡣᙜ࡚ࡣࡲࡽ࡞࠸ྍ⬟ᛶࡀ࠶఩⨨࡛ࡢ⥺㔞ࣉࣟࣇ࢓࢖ࣝࡣࠊ࡛ࡇࡰࡇ࡜ࡋࡓᙧ≧ࡿࠋ࡜࡞ࡿࡇ࡜ࡀ࠶ࡿࠋ㟁఩ィࡢࢤ࢖ࣥࠊࣜࣇ࢓ࣞࣥࢫ ࠸ࡃࡘ࠿ࡢ TPS ࡛ࡣࠊไືᨺᑕ⥺ᡂศࡢ᝟ሗࡀ㔜᳨ฟჾࡢタ⨨఩⨨ࠊࢫ࢟ࣕࣥ᪉ྥࠊ᳨ฟჾࡢ⛣ື㏿

せ࡜࡞ࡿࠋไືᨺᑕ⥺ࡣࠊ(1) ࢞ࣥࢺࣜ࣊ࢵࢻࠊ(2) 㖄ᗘࠊࢧࣥࣉࣜࣥࢢ᫬㛫ࠊ⧞ࡾ㏉ࡋᩘࠊ࡞࡝ࢫ࢟ࣕࣥ

ࣈࣟࢵࢡ࠾ࡼࡧ(3) Ỉ࡜㟁Ꮚ⥺ࡢ┦஫స⏝࡟ࡼࡾⓎࡢᨵၿࡢࡓࡵ࡟࠸ࡃࡘ࠿ࡢせᅉࢆ᳨ウࡍ࡭ࡁ࡛࠶

⏕ࡍࡿࠋࡑࢀࡒࢀࡢᙳ㡪ࢆ㝖ཤࡍࡿࡇ࡜࡛ࠊไືᨺ

ࡿࠋ⮫ᗋ࣮ࣔࢻ᳨࡛ドࡍࡿᚲせࡀ࠶ࡿࡀࠊࣜࢽ࢔ࢵ

ᑕ⥺ࡢ๭ྜࢆṇ☜࡟ྲྀᚓ࡛ࡁࡿ᪉ἲࢆ Zhu ࡽࡀሗ࿌ࢡ࡟ࡼࡗ࡚ࡣࠊࢧ࣮࣎ไᚚࢆ࢜ࣇ࡟ࡍࡿࡇ࡜࡟ࡼࡗ

⪅ὀ 5

ࠋ(2)

ࡋ࡚࠸ࡿ

206

ࠋ

࡚ࣉࣟࣇ࢓࢖ࣝࢆᨵၿࡍࡿࡇ࡜ࡀ࡛ࡁࡿࡶࡢࡀ࠶

㟁Ꮚ⥺⏝ࢲ࢖࣮࢜ࢻ᳨ฟჾ࡛࢝ࢵࢺ࢔࢘ࢺ↷ᑕ㔝࡟ࡼࡿ PDD ࢆᐃ࡟ὀពࡀᚲせ࡜࡞ࡿࠋࣉࣟࣇ

ᐃࡍࡿሙྜࠊࢲ࢖࣮࢜ࢻ࡜ගᏊ

⥺࡜ࡢ┦஫స⏝࡟࢚ࢿࣝࢠ࣮౫Ꮡᛶࡀ࠶ࡿࡓࡵࠊไ

ࡿࠋࡲࡓࠊ≉ᐃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡛ࡣࠊࣉࣟ
ࣇ࢓࢖ࣝࡣ⮬ືࢤ࢖ࣥタᐃ࡜ࣂࢵࢡࢢࣛ࢘ࣥࢻࢆ
෌ㄪᩚࡍࡿࡇ࡜࡟ࡼࡗ࡚ᨵၿࡉࢀࡿྍ⬟ᛶࡶ࠶ࡿࠋ
Fig. 9 ࡟ࠊ㟁Ꮚ⥺ࣉࣟࣇ࢓࢖ࣝࡢࢫ࢟ࣕࣥ㏿ᗘ࡟ࡼヂ⪅ὀ5Ỉ㸭ࢩࣜࢥࣥࡢᖹᆒไ㝈㉁㔞⾪✺㜼Ṇ⬟ẚࡀࠊ౑⏝ࡍࡿ࢚ࢿࣝࢠ࣮࡟ࢃࡓࡾ኱ࡁࡃኚ໬ࡋ࡞࠸ࡓ
ࡵࠋ

46

ヂ⪅ὀ6

ṇ☜࡞ไືᨺᑕ⥺ᡂศࢆྲྀᚓࡍࡿࡓࡵ࡟ࡣࠊ
㟁㞳⟽⥺㔞ィ࡛ ᐃࡍࡿᚲせࡀ࠶ࡿࠋV. 電子線

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)ࡿᙳ㡪ࢆ♧ࡍࠋⰋዲ࡞ࣉࣟࣇ࢓࢖ࣝࢹ࣮ࢱࢆྲྀᚓࡍ

SSD ࡜୙ᩚᙧ࡞࢝ࢵࢺ࢔࢘ࢺࡢ⥺㔞/MU ࢆணࡿࡓࡵ࡟ࡣࠊࢫ࢟ࣕࣥ㏿ᗘࡢపῶࡸࢧࣥࣉࣜࣥࢢ᫬

ࡿࡓࡵ࡟ࠊࢡ࣮ࣛࢡࢯࣥἲ࡟㢮ఝࡋࡓᡪᙧ✚ศἲࢆ㛫ࡢᘏ㛗ࡀᚲせ࡜࡞ࡿࠋ౑⏝ࡍࡿࡇ࡜ࡀሗ࿌ࡉࢀ࡚࠸ࡿ 208, 209ࠋ

V.B. 㟁Ꮚ⥺࣏࢖ࣥࢺ⥺㔞ࢹ࣮ࢱ

V.B.3. ௬᝿/ᐇຠ⥺※఩⨨

V.B.1. ࢥ࣮ࣥಀᩘ 㟁Ꮚ⥺ࡣ≀㉁ࢆ㏻㐣ࡍࡿ㝿࡟ᩓ஘ࡉࢀࡿࡓࡵࠊཝ ௵ពࡢࢥ࣮ࣥࡢฟຊಀᩘࡣࠊᇶ‽ࢧ࢖ࢬࡢࢥ࣮ࣥ
22ࡍᐦ࡞㊥㞳ࡢ㏫஧஌๎࡟ᚑࢃ࡞࠸ࠋ≉࡟ࠊࢥ࣓࣮ࣜࢱ

㸦㏻ᖖࡣ 10 × 10 cm ࡲࡓࡣ 15 × 15 cm 㸧ࡢ᭱኱῝࡜ࢥ࣮ࣥ࠿ࡽࡢᩓ஘㟁Ꮚ⥺ࡣࠊ༢୍ࡢ⥺※࡜ࡋ࡚ࡢ྾཰⥺㔞㸦Ddmax㸧࡟ᑐࡍࡿ௵ពࡢࢥ࣮ࣥࡢ Ddmax ࡢ≉ᛶ࡟ᚑࢃ࡞࠸ 210ࠋࡇࡢ≉ᛶࢆᢕᥱࡍࡿࡓࡵ࡟ࠊ㏫ẚ࡛࠶ࡿࠋ25 × 25 cm2 ࡢࢥ࣮ࣥಀᩘࡣࠊ30 × 30 cm2஧஌๎ࡀ㐺⏝࡛ࡁࡿࡼ࠺࡞௬᝿ⓗ࡞⥺※఩⨨ࢆỴ௨ୖࡢỈࣇ࢓ࣥࢺ࣒࠿ᅛయࣇ࢓ࣥࢺ࣒࡛

ᐃࡍࡿ᪉ἲࡀ࠶ࡿ 56ࠋᐃࡍ࡭ࡁ࡛࠶ࡿࠋྠ୍ࡢ〇㐀ᴗ⪅࡟ࡼࡿྠࡌࣔࢹࣝࡢ἞⒪ ࣂ࣮ࢳࣕࣝࢯ࣮ࢫ㸦௬᝿⥺※㸧ࢆ᥎ᐃࡍࡿ᪉ἲ࡜

⿦⨨㸦౛࠼ࡤ 2 ྎࡢ 21EX㸧࡛࠶ࡗ࡚ࡶࠊࢥ࣮ࣥಀ

ࡋ࡚ࢠࣕࢵࣉἲ࡜VTFἲ 205, 211 ࡀᥦ᱌ࡉࢀ࡚࠸ࡿࠋ

ᩘࡣ␗࡞ࡿࡇ࡜ࡀ࠶ࡿࡀࠊࡑࡢᕪࡣ኱ࡁࡃࡣ࡞࠸

Khan ࡟ࡼࡿࢠࣕࢵࣉἲࡶࡋࡃࡣᐇຠ SSD ἲࡣࠊྛ

㸦2%⛬ᗘ㸧ࡔࢁ࠺ࠋྠ୍ࣔࢹࣝࡢ␗࡞ࡿ⿦⨨ࡢࢥ࣮㊥㞳࡟࠾ࡅࡿ㟁Ꮚ⥺⥺㔞ࢆ㏫஧஌๎࡟ࡼࡗ࡚ィ⟬ࣥಀᩘࢆὶ⏝ࡍࡿሙྜࡣࠊ࠶ࡽ࠿ࡌࡵ඲࡚ࡢ࢚ࢿࣝ

ࡇࡢᡭἲࡣẚ㍑ⓗ༢⣧࡛ࠊࡍࡿࡓࡵࡢᡭἲ࡛࠶ࡿ 88ࠋࢠ࣮࡜ࢥ࣮࡛ࣥࢥ࣮ࣥಀᩘࢆ

⿦⨨ࠊ↷ᑕ㔝ࢧ࢖ࢬࠊ࢚ࢿࣝࢠ࣮࡟౫Ꮡࡍࡿᐇຠ

ᐃࡋ࡚ࠊ☜ㄆࡍࡿࡇ

SSD ࡢỴᐃࡀᚲせ࡜࡞ࡿࠋ㟁Ꮚ⥺ࢥ࣮ࣥ࡜Ỉ㠃ࡢࢠ࡜ࢆ᥎ዡࡍࡿࠋ

ࣕࢵࣉࢆኚ໬ࡉࡏ࡞ࡀࡽ dmax ࡛
V.B.2. ࢝ࢵࢺ࢔࢘ࢺಀᩘ

ᐃࢆ⾜࠸ࠊࢠࣕࢵ

ࣉ࡟ᑐࡍࡿ I0/I ࡢᖹ᪉᰿ࢆࣉࣟࢵࢺࡍࡿ࡜ࠊࡑࡢഴ ࢝ࢵࢺ࢔࢘ࢺಀᩘࡣࠊྛࢥ࣮࡛ࣥࡢ࢝ࢵࢺ࢔࢘ࢺ
ࡢ᭷↓࡟ࡼࡿࠊࡑࢀࡒࢀࡢdmax࡛ࡢ⥺㔞ẚ࡛࠶ࡿヂ⪅ࡁ࡟ࡼࡗ࡚ᐇຠ SSD ࡀỴᐃࡉࢀࡿࠋICRU-35 ࡜ van
Battum ࡽ࡟ࡼࡗ࡚㏙࡭ࡽࢀ࡚࠸ࡿ Sigma-theta-Fὀ7ࠋ㢖⦾࡟⏝࠸ࡿ࢝ࢵࢺ࢔࢘ࢺಀᩘࡣࠊ࢚ࢿࣝࢠ࣮

㸦VTF㸧ࡣࠊ᭱⤊ⓗ࡞↷ᑕ㔝㝈ᐃჾࡢ࠶ࡿᖹ㠃࡛ࡢࠊẖࡢ⾲ࢆ‽ഛࡍࡿ࡜Ⰻ࠸ࠋ࢝ࢵࢺ࢔࢘ࢺࡢᙧ≧ࡣ㛗࢞࢘ࢫศᕸ࡜ࡋ࡚ぢ✚ࡽࢀࡓゅᗘศᕸࡢ஧஌ᖹᆒ

᪉ᙧࠊ෇ࠊᴃ෇ࡸṇ᪉ᙧ࡞࡝ࡀ࠶ࡿࠋ࢝ࢵࢺ࢔࢘ࢺ

್ࡢᖹ᪉᰿㸦root-mean-square㸧࡛࠶ࡿ 205, 211ࠋࡇࡢ

ಀᩘࡣࠊ㏻ᖖࡑࢀࡽࡢ➼౯ṇ᪉ᙧ࡛⾲࡜ࡋ࡚ࡲ࡜ࡵ

᪉ἲࡣࠊ᭱኱ࢧ࢖ࢬࡢࢥ࣮ࣥࢆ⏝࠸࡚ࠊ␗࡞ࡿ࢔࢖

ࡽࢀࡿࠋ㟁Ꮚ⥺ࡢ➼౯ṇ᪉ᙧ࡜ฟຊ⥺㔞ࡢ⟬ฟࡣࠊࢯࢭࣥࢱ᳨ฟჾ㛫㊥㞳࡛ࠊࣇ࢕࣒ࣝࡸ 217 ࢲ࢖࣮࢜௚ࡢᩥ⊩࡛ヲ⣽࡟㏙࡭ࡽࢀ࡚࠸ࡿ 22,56,205,207ࠋ

ࢻ 34 ࡛

22

 1 × 2 cm ࠊ2 × 2 cm ࡞࡝ࡢ㠀ᖖ࡟ᑠࡉ࠸࢝ࢵࢺ࢔

ᐃࡉࢀࡓ✵୰࡛ࡢ༙ᙳ㒊ศ㸦20-80%㸧ࡢࣉࣟࣇ࢓࢖ࣝࢆᚲせ࡜ࡍࡿࠋ࢘ࢺࡢ dmax ࡣࠊ኱ࡁ࡞࢝ࢵࢺ࢔࢘ࢺ࡜␗࡞ࡿࡇ࡜ࡀ
࠶ࡿࡓࡵࠊྛ࢝ࢵࢺ࢔࢘ࢺ࡛

ᐃ࡟ࡼࡾỴᐃࡍࡿᚲ

V.B.4. ࣔࣥࢸ࣮࢝ࣝࣟ࣋ࢫࡢ⥺㔞ィ⟬ࡢࡓࡵࡢࢹ

せࡀ࠶ࡿࠋࡇࡢሙྜࠊ㟁㞳⟽ࡢ㑅ᢥ࡜タ⨨఩⨨⢭ᗘ࣮ࢱࡀࠊ㠀ᖖ࡟㔜せ࡜࡞ࡿࠋ ࣔࣥࢸ࢝ࣝࣟࢩ࣑࣮ࣗࣞࢩࣙࣥ࡟ࡼࡿ㟁Ꮚ⥺ࣅ SSD㸻110 cm ࡢࡼ࠺࡟㊥㞳ࢆᘏ㛗ࡋࡓ࢝ࢵࢺ࢔

࣮࣒ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ࡟㛵ࡍࡿ◊✲ࡀᗈࡃ⾜ࢃ࢘ࢺಀᩘࡣࠊ(1)ࢀ࡚࠸ࡿ 13, 157, 210, 218-221ࠋࡑࢀࡽࡣࠊࣔࣥࢸ࢝ࣝࣟἲ

ᐃࢆ⾜࠺ࠊࡲࡓࡣࠊ(2) ࢥ࣑ࢵࢩࣙࢽࣥࢢࡉࢀࡓ 100 cm SSD ࡛ࡢ࢝ࢵࢺ࢔࢘ࢺಀᩘ

࡟ࡼࡗ࡚ࣅ࣮࣒ࢹ࣮ࢱࢆసᡂ࡛ࡁࡿྍ⬟ᛶࢆ᫂ࡽ࠿ࡽࠊ௬᝿ SSD ࢆ⏝࠸ࡿࠊࡢ 2 ࡘࡢ᪉ἲ࡛⟬ฟ࡛ࡁ࠿࡟ࡋࡓࠋPhase-space ࢹ࣮ࢱ㸦ྛ⢏Ꮚࡢ㟁Ⲵࠊ఩⨨ࠊᐃ࡜௬᝿ SSD ࡟ࡼࡿ⟬ฟ㸧㛫ࡢ᪉ྥࠊ࢚ࢿࣝࢠ࣮࡜ࣄࢫࢺ࣭ࣜࢱࢢࡢࢹ࣮ࢱ㸧ࡣࠊ

ࡿࠋ2 ࡘࡢ᪉ἲ㸦┦㐪ࡣ 2%௨ෆ࡛࠶ࡿࠋs2%ࡢ⥺㔞⢭ᗘ࡛ᵝࠎ࡞ࣔࣥࢸ࣮࢝ࣝࣟ࣋ࢫࡢ἞⒪ィ⏬࡟ᚲせ࡜ࡉࢀࡿࠋࣔ
ࣥࢸ࢝ࣝࣟィ⟬ࡢጇᙜᛶࢆ᳨ドࡍࡿࡓࡵࠊࣔࣥࢸ࢝

ヂ⪅ὀ7࢝ࢵࢺ࢔࢘ࢺ࡜ࡣ㟁Ꮚ⥺ࢥ࣮ࣥࡢඛ➃㒊࡟タ⨨ࡍࡿࣈࣟࢵࢡࢆᣦࡍࠋ

ࣝࣟࢩ࣑࣮ࣗࣞࢩࣙࣥ࡜
せࡀ࠶ࡿࠋᚑ᮶ࡢ

ᐃ࡜ࢆ⤌ࡳྜࢃࡏࡿᚲ

ᐃࢹ࣮ࢱ㸦౛࠼ࡤࠊPDDࠊࣉࣟ

47

医学物理 第 33 巻 第 1 号

VI. ビームデータの加工ࣇ࢓࢖ࣝࠊฟຊಀᩘࠊ⤯ᑐ⥺㔞㸧࡟ຍ࠼࡚ࠊࣔࣥࢸ
࣮࢝ࣝࣟ࣋ࢫࡢࢩࢫࢸ࣒ࡢࡓࡵ࡟௚ࡢࢥ࣑ࢵࢩࣙ
ࢽࣥࢢ᝟ሗࡀᚲせ࡞ࡇ࡜ࡀ࠶ࡿ 9, 13, 220-226ࠋ 㟁Ꮚ⥺ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ࡛ࠊࣔࣥࢸ࢝ࣝࣟィ⟬࡟ࡼࡗ࡚ᚓࡓ࢚ࢿࣝࢠ࣮ࢫ࣌ࢡࢺࣝ࡜⥺㔞ィ⟬ࢆᐇドࡍࡿࡓࡵࡢࢹ࣮ࢱࡀᚲせ࡜࡞ࡿࡇ࡜ࡀ࠶ࡿࠋࡑ
ࢀࡒࢀࡢࣔࣥࢸ࣭࢝ࣝࣟ࢔ࣝࢦࣜࢬ࣒ࠊ౛࠼ࡤ࣎ࢡ
ࢭ࣭ࣝࣔࣥࢸ࢝ࣝࣟ 222 ࡲࡓࡣ࣐ࢡࣟࣔࣥࢸ࢝ࣝࣟ
223, 224

࡛ࠊࢥ࣑ࢵࢩࣙࢽࣥࢢ࡟ᚲせ࡞ࢹ࣮ࢱࢭࢵࢺ

ࡀ␗࡞ࡿࡇ࡜ࡀ࠶ࡿࠋ
VI. ࣅ࣮࣒ࢹ࣮ࢱࡢຍᕤ
VI.A. ࢹ࣮ࢱࡢຍᕤ࡜᧯స

FIG. 13. Effect of data smoothing on the 6 MV 60° wedge profiles.
Circles are drawn to show the effect of smoothing.

 ࢫ࢟ࣕࣥ࠾ࡼࡧࣀࣥࢫ࢟ࣕࣥࡢࣅ࣮࣒ࢹ࣮ࢱྲྀᚓᚋࠊTPS ࡟ࢹ࣮ࢱࢆⓏ㘓ࡍࡿ๓࡟ຍᕤࡀᚲせ࡞ࡇ࡜ࡀ࠶ࡿࠋከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡛ࡣࠊࣉࣟ
ࣇ࢓࢖ࣝࡢࢭࣥࢱࣜࣥࢢࠊࢫ࣒࣮ࢪࣥࢢࡸᑐ⛠໬࡞࡝ࠊከᩘࡢࢶ࣮ࣝࡀ౑⏝࡛ࡁࡿࠋຍᕤࡢ⛬ᗘࡣࠊࢫ࢟ࣕࢼࡢࢱ࢖ࣉ㸦ࢲ࢖࣮࢜ࢻࡸ㐃⥆ⓗ࡞⥺㔞⋡࣮ࣔࢻ࡛ࡢࢫ࢟ࣕࣥ㸧ࠊࢭࢵࢺ࢔ࢵࣉ⢭ᗘ࠾ࡼࡧ⿦⨨⮬యࡢ≉ᛶ࡞࡝࡟౫Ꮡࡍࡿࠋ
VI.B. ࢫ࣒࣮ࢪࣥࢢ࣭࣑࣮ࣛࣜࣥࢢ࠾ࡼࡧࢧ࣐ࣛ࢖
ࢪࣥࢢ ࡍ࡭࡚ࡢ

ᐃࢹ࣮ࢱࡣࠊࢩࢫࢸ࣒࡟౫Ꮡࡋࡓࣀ࢖

ࢬࢆྵࡴࠋࢫ࣒࣮ࢪࣥࢢ࡜ࣇ࢕ࣝࢱࣜࣥࢢ᧯సࡣࠊ
ࣀ࢖ࢬࢆ㝖ཤࡋࠊ┿ࡢࢹ࣮ࢱࢆྲྀࡾฟࡍࡇ࡜࡟ᙺ❧ࡘࠋࡇࢀࡣపᇦ㏻㐣ࣇ࢕ࣝࢱ࡛ࡶ࠶ࡾࠊ㠀㐃⥆ⓗࠊ㗦ᩄࠊᲲ≧࡞࡝ࡢ㧗࿘Ἴᡂศࢆ㝖ཤࡍࡿࠋࢫ࣒࣮ࢪ
ࣥࢢἲ࡟ࡣࠊ᭱ᑠ஧஌ࠊ୰ኸ್ࠊ⟬⾡ᖹᆒࠊᗄఱᖹ
ᆒࠊ⛣ືᖹᆒࠊ3 ḟࢫࣉࣛ࢖ࣥࠊᣦᩘ㛵ᩘࠊໟ⤡⥺ࠊ࢞࢘ࢩ࢔ࣥࠊࣇ࣮࢚ࣜኚ᥮ࠊ࣋ࢪ࢙ἲ࡞࡝ࠊከᩘࡢ
ᡭἲࡀ࠶ࡿ 227 - 229ࠋࡋ࠿ࡋ࡞ࡀࡽࠊࡍ࡭࡚ࡢᡭ㡰ࡀࠊ‶㊊࡛ࡁࡿ⤖ᯝࢆ୚࠼ࡿ࡜࠸࠺ࢃࡅ࡛ࡣ࡞࠸ࠋ࡝ࡢ
ᡭ㡰ࡀࠊ ᐃࡋࡓ᭤⥺ࡢᮏ㉁ⓗ࡞ᙧ≧ࢆᦆ࡞ࢃࡎ࡟ࠊ
ࣀ࢖ࢬࢆపῶ࡛ࡁࡿ࠿ࢆุ᩿ࡍࡿࡓࡵࠊ␗࡞ࡿࢫ࣒
࣮ࢪࣥࢢ᧯సࢆヨࡉ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋࡍ࡞ࢃࡕࠊ
60°࢙࢘ࢵࢪࡢ⥺㔞ࣉࣟࣇ࢓࢖࡛ࣝࠊᲲ≧ࡢࣀ࢖ࢬࢆ㝖ཤࡍࡿࡼ࠺࡞ሙྜ࡛࠶ࡿࠋ㐣ᗘࡢࢫ࣒࣮ࢪࣥࢢࡀᚲせ࡞ሙྜࡣࠊࢫ࢟ࣕࣥ㏿ᗘࡢపୗࡸࢧࣥࣉࣜࣥ
ࢢ㛫㝸ࡢᘏ㛗࡞࡝ࢆ⾜࠸ࠊࢹ࣮ࢱࢆᨵၿࡉࡏࡿࡇ࡜ࡀᚲせ࡜࡞ࡿࠋ

48

ࢭࣥࢱࣜࣥࢢ࣭ࢶ࣮ࣝࡣࠊ࣮࢜ࣉࣥ↷ᑕ㔝࡛ࡣ㐺ษ࡟ᶵ⬟ࡍࡿࠋࡋ࠿ࡋ࡞ࡀࡽࠊ෌ࢭࣥࢱࣜࣥࢢࡢ㔞ࡀ㐣๫࡛࠶ࡿ㸦౛࠼ࡤ 0.05 cm ࢆ㉸࠼ࡿ㸧ሙྜࡣࠊࢫ࢟ࣕࣥࢭࢵࢺ࢔ࢵࣉࡢࣅ࣮࣒୰ᚰࡢᨵၿࢆ᳨ウࡍࡿᚲせࡀ࠶ࡿࠋ౛࠼ࡤࠊࢭࣥࢱࣜࣥࢢ࣭ࢶ࣮ࣝࡣ
࢙࢘ࢵࢪࢆ⏝࠸ࡓ↷ᑕ㔝࡟ࡣᶵ⬟ࡋ࡞࠸ࡓࡵࠊ఩⨨ㄗᕪࢆ⏕ࡌࡿྍ⬟ᛶࡀ࠶ࡿࠋ ࣉࣟࣇ࢓࢖ࣝࡢᑐ⛠໬ࢆ⾜࠺͆make symmetrical͇
ࡸ͆mirror͇ࢶ࣮ࣝࡣࠊ࣮࢜ࣉࣥ↷ᑕ㔝࡛ࡣ᭷⏝࡛࠶ࢁ࠺ࠋࡋ࠿ࡋ࡞ࡀࡽࠊ㝖ཤࡍ࡭ࡁ㠀ᑐ⛠ࡢ㔞ࡀ㐣๫࡞ሙྜ㸦࣮࢜ࣉࣥ↷ᑕ㔝ࡢࢫ࡛࢟ࣕࣥ 0.5%ࢆ㉸࠼ࡿ㠀ᑐ⛠ᛶ࡞࡝㸧ࠊ3 ḟඖỈࣇ࢓ࣥࢺ࣒ࡀỈᖹタ⨨ࡉࢀ࡚࠸ࡿ࠿ࠊࡲࡓࣅ࣮࣒ࡢᑐ⛠ᛶ࡞࡝ࢆ☜ㄆࡍ࡭ࡁ࡛࠶ࡿࠋࡇࢀࡣ࢙࢘ࢵࢪ↷ᑕ㔝࠿ࡽ࣮࢜ࣉࣥ↷ᑕ㔝ࡢ㠀ᑐ⛠ࢆ㝖ཤࡍࡿ᪉ἲࡣ↓࠸ࡓࡵ࡛࠶ࡿࠋ ᐃࢹ࣮ࢱ࡟㔜኱࡞ຍᕤ㸦ࡍ࡞ࢃࡕࠊࢭࣥࢱࣜࣥࢢࠊࢫ࣒
࣮ࢪࣥࢢࠊ㠀ᑐ⛠ࢆಟṇࡍࡿ࣑࣮ࣛࣜࣥࢢ㸧ࢆᚲせ࡜ࡍࡿሙྜࡣࠊࢹ࣮ࢱࡢ෌ྲྀᚓࢆ᳨ウࡍ࡭ࡁ࡛࠶ࡿࠋ
Ⰻዲ࡞ᐃࢹ࣮ࢱࢭࢵࢺࡣࠊ᭱ప㝈ࡢຍᕤ࡛༑ศ࡛

࠶ࡿࠋ
VI.B.1. ᩘᏛ㛵ᩘ࡜ࣇ࢕ࣝࢱ
ࡓ࠸࡚࠸ࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣࠊࢫ࣒࣮ࢪࣥ
ࢢࠊ࣑࣮ࣛࣜࣥࢢ࠾ࡼࡧࢧ࣐ࣛ࢖ࢪࣥࢢ࡟౑⏝ࡍࡿ㛵ᩘ࡜ࣇ࢕ࣝࢱࡢヲ⣽࡞ㄝ᫂᭩ࡀ⏝ពࡉࢀ࡚࠸ࡿࠋ
ࢩࢫࢸ࣒ࡢ᝟ሗࡣࠊ〇㐀ᴗ⪅ࡢㄝ᫂᭩ࢆཧ↷ࡋ࡚ᚓࡿᚲせࡀ࠶ࡿࠋࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡟௜ᒓࡍࡿ㏻

VII. まとめと勧告

Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)ᖖࡢࢯࣇࢺ࢙࢘࢔ࡣࠊ⛣ືᖹᆒࠊ3 ḟࢫࣉࣛ࢖ࣥࠊ
ෆᤄᶵ⬟࡜ࣇ࣮࢚ࣜኚ᥮࡞࡝ࡀ฼⏝࡛ࡁࡿࠋ࠶ࡽ࠿

(1) ⿦⨨ࡢ✀㢮ࠊTPS ࡟≉᭷࡞ᚲせ᮲௳ࠊ᧯సୖࡢ

ࡌࡵᇶ‽࡜࡞ࡿ↷ᑕ㔝ࢹ࣮ࢱ࡜ẚ㍑ࡋ࡚ࠊࡇࢀࡽࡢ

ၥ㢟Ⅼࠊ⿦⨨ࡢ᧯స≧ែ࡜ࣅ࣮࣒࢚ࢿࣝࢠ࣮࡟

ᶵ⬟ࡢ᭷ຠᛶࢆ☜ㄆࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋ

ࡼࡿࢹ࣮ࢱྲྀᚓࡢ⠊ᅖࢆつᐃࡍࡿࠋ(2) ᘧ(1)ࡢ௬ᐃ࡟ᇶ࡙࠸࡚ࠊ⿦⨨ࡢࢥ࣑ࢵࢩࣙࢽࣥ

VI.B.2. ࢫ࣒࣮ࢪࣥࢢ࡟࠾ࡅࡿࡺࡀࡳ

ࢢࡢࡓࡵ࡟ᚲせ࡞᫬㛫ࢆᴫ⟬ࡍࡿࠋ ከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣࠊ ᐃࢹ࣮ࢱࢆࢫ

(3) ឤᗘࡀ㧗ࡃࠊయ✚ࡀᑠࡉࡃࠊࣀ࢖ࢬࡀᑠࡉࡃࠊ

࣒࣮ࢪࣥࢢࡍࡿࡓࡵ࡟ᵝࠎ࡞ࣇ࢕ࣝࢱࡀ⏝ពࡉࢀ࠿ࡘ⥺㔞⋡౫Ꮡᛶ࠾ࡼࡧ࢚ࢿࣝࢠ࣮౫Ꮡᛶࡢ

࡚࠸ࡿࠋࡶࡗ࡜ࡶࡼࡃ฼⏝ࡉࢀࡿࡶࡢࡣࠊ3 ḟࢫࣉᑠࡉ࠸㐺ษ࡞᳨ฟჾࢆ⏝࠸ࡿࠋࣛ࢖ࣥἲ࡛࠶ࡿࠋࡓࡔࡋ࢜ࣜࢪࢼࣝࢹ࣮ࢱࢆࢫ࣒࣮

(4) య✚ࡢᑠࡉ࠸㟁㞳⟽⥺㔞ィࡣࠊගᏊ⥺ࡢ┦ᑐ⥺ࢪࣥࢢࡍࡿࡇ࡜࡛ࠊࢹ࣮ࢱࢆṍࡵ࡚ࡋࡲ࠺ࡇ࡜ࡀ࠶
ࡿࠋ≉࡟ࠊ༙ᙳ㒊ࡸ࢙࢘ࢵࢪࣉࣟࣇ࢓࢖ࣝࡢࡼ࠺࡞

㔞ᐃ࡟ᮃࡲࡋ࠸ࠋ

(5) 㟁Ꮚ⥺⏝ࢲ࢖࣮࢜ࢻ᳨ฟჾࡣࠊ㟁Ꮚ⥺ࡢ┦ᑐ⥺⥺㔞໙㓄ࡢ኱ࡁ࡞㡿ᇦ࡛㢧ⴭ࡜࡞ࡿࠋFig. 13 ࡟ࠊࢫ㔞ࡢ࣒࣮ࢪࣥࢢࢆ⧞ࡾ㏉ࡋࡓࡇ࡜࡟ࡼࡿࣉࣟࣇ࢓࢖ࣝ

ࡍࡿᛂ⟅ࡀ␗࡞ࡿ஦ࡀ࠶ࡿࡓࡵࠊไືᨺᑕ⥺ᡂࡢኚᙧࢆ♧ࡍࠋ

ศࡣ㟁㞳⟽⥺㔞ィ࡛ ࢫ࣒࣮ࢪࣥࢢࡀఱᅇࡲ࡛チᐜࡉࢀࡿ࠿࡟ࡘ࠸࡚

(6)ᐃ࡟ᮃࡲࡋ࠸ࠋࡓࡔࡋࠊไືᨺᑕ⥺࡟ᑐᐃࡍࡿࠋᐃࢆ㛤ጞࡍࡿ๓࡟ࠊࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢ

ࡢ࣮ࣝࣝࡸሗ࿌ࡣ࡞࠸ࠋ୍⯡ⓗ࡟ࡣࢹ࣮ࢱࢆṍࡵࡎࣛ࣋ࣜࣥࢢ㸦x ࡸ y ࡞࡝㍈ྡࡢタᐃ㸧࡜タ⨨఩࡟ࠊ༢⣧࡟ࢫ࣒࣮ࢪࣥࢢ࡛ࡁࡿࡼ࠺࡞࢜ࣜࢪࢼࣝࢹ

⨨ࢆ☜ㄆࡍࡿࠋ

࣮ࢱࢆྲྀᚓࡍࡿᚲせࡀ࠶ࡿࠋ1㹼2 ᅇࡢࢫ࣒࣮ࢪࣥࢢ

(7) ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡟ࡣࠊ㐺ษ࡞㏿ᗘࠊ㐜ᘏࡣチᐜࡉࢀࡿࡔࢁ࠺ࠋ஦ᚋホ౯ࡢࡓࡵ࡟࢜ࣜࢪࢼࣝ

᫬㛫࠾ࡼࡧࢧࣥࣉࣜࣥࢢ᫬㛫ࢆタᐃࡍࡿࠋࡢࢹ࣮ࢱࢆ↓ຍᕤࡢ≧ែ࡛ಖᏑࡍࡿࡇ࡜ࢆᙉࡃ᥎

(8) PDD ࡢࢫ࢟ࣕࣥࡣࠊ⾲㠃Ѝ῝㒊ࡼࡾ῝㒊Ѝ⾲㠃ዡࡍࡿࠋࡢ᪉ྥ࡛ྲྀᚓࡍࡿࠋ
(9) ࢹ࣮ࢱࡢྲྀᚓ࡟せࡍࡿ᫬㛫࡜⢭ᗘࢆ⪃៖ࡋ࡚ࠊ

VI.C. ࣀࣥࢫ࢟ࣕࣥࢹ࣮ࢱࡢຍᕤ㐺ษ࡞ᐃ㛫㝸ࢆタᐃࡍࡿࠋ ࣀࣥࢫ࢟ࣕࣥࢹ࣮ࢱ࡟ࡘ࠸࡚ࡣࠊࣅ࣮࣒ࣃ࣓࣮ࣛ

(10) ᳨ฟჾ࡟㐺ษ࡞༳ຍ㟁ᅽ࡜ᴟᛶࢆタᐃࡍࡿࠋࢱࡢ᫂☜࡞࢚࣮ࣛ㸦እࢀ್㸧ࢆᙉㄪ࡛ࡁࡿࡓࡵࠊࢢ

(11) ↷ᑕ㔝࡟ධࡿࢣ࣮ࣈࣝࡢ㛗ࡉࡣࠊྍ⬟࡞㝈ࡾ▷ࣛࣇ໬ࢆ່ࡵࡿࠋ౛࠼ࡤࠊ↷ᑕ㔝ࢧ࢖ࢬ࡟ᑐࡍࡿ Scࠊ
Sp ࡢࣉࣟࢵࢺࡣࠊᑠࡉ࠸↷ᑕ㔝࡛ᛴ⃭࡟ኚ໬ࡋࠊ୍
᪉኱ࡁ࡞↷ᑕ㔝࡛ࡣࠊ⦆ࡸ࠿࡞࣮࢝ࣈࢆ♧ࡉ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋ᫂ࡽ࠿࡟࣮࢝ࣈ࡟ἢࢃ࡞࠸

ᐃⅬࡣࠊ

ࡃࡍࡿࠋ
(12) ࢹ࣮ࢱ

ᐃࡢ✵㛫ศゎ⬟ࡀ᭱㧗࡜࡞ࡿࡼ࠺࡟ࠊ

᳨ฟჾࡢ▷㍈ࢆᐃ᪉ྥ࡜୍⮴ࡉࡏࡿࠋ(13) TPS ࡢᇶ‽᮲௳࡟࡛ࡁࡿࡔࡅ㏆࠸ṇつ໬ࡢⅬィ⟬㛫㐪࠸ࢆ෌☜ㄆࡍ࡭ࡁ࡛࠶ࡿࠋࡲࡓᚲせ࡟ᛂࡌ࡜ᡭ㡰ࢆ⏝࠸ࡿ㸦౛ࠊගᏊ⥺ࡣࠊ⾲㠃࡛ࡣΰධ࡚ࠊࢹ࣮ࢱࡢ⢭ᗘࢆྥୖࡉࡏࡿࡓࡵ෌

㟁Ꮚ࡟ࡼࡿㄗᕪࢆᅇ㑊ࡍࡿࡓࡵࠊdmax ࡛ṇつ໬ᐃࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋ

ࡋ࡞࠸࡞࡝㸧ࠋ(14) ࡍ࡭࡚ࡢ

VII. ࡲ࡜ࡵ࡜່࿌

ᐃࢹ࣮ࢱ࡟ࠊ⡆₩࡞࣏࣮ࣞࢺࢆ᭩ࡃࠋ

(15) ࣏࣮ࣞࢺ࡜

ᐃࢹ࣮ࢱࢆ෌☜ㄆࡍࡿࠋ༑ศ࡞⤒VII.A. ່࿌㦂ࢆ᭷ࡍࡿㄆᐃ་Ꮫ≀⌮ኈࡀ ௚ࡢ࣏࣮ࣞࢺ࡜ྠᵝࠊࡇࡢᩥ❶ࡶᇳ➹᫬ࡢ᭱᪂≧❧᳨ドࢆ⾜࠸ࠊ࣏࣮ࣞࢺࢆసᡂࡍࡿࠋ

ἣࢆ཯ᫎࡋࡓࡶࡢ࡛࠶ࡿࠋ௒ᚋࡢ἞⒪⿦⨨ࠊ἞⒪ィ
⏬ࠊ ᐃᢏ⾡ࡢⓎᒎ࡟ࡼࡾࠊࡇࡢ࣏࣮ࣞࢺ࡛ࡢ᥎ዡ

ᐃࢹ࣮ࢱࡢ⊂(16) ࡍ࡭࡚ࡢ㟁Ꮚࢹ࣮ࢱࠊゎᯒࢹ࣮ࢱ࠾ࡼࡧࢫࣉࣞ
ࢵࢻࢩ࣮ࢺࡢࣂࢵࢡ࢔ࢵࣉࢆྲྀࡿࠋ

ࡀ≧ἣ࡜ྜࢃ࡞ࡃ࡞ࡿࡇ࡜ࡶ⪃࠼ࡽࢀࡿࡓࡵࠊㄞ⪅(17) ࣋ࣥࢲ࣮࠿ࡽᥦ౪ࡉࢀࡓࢹ࣮ࢱࡣࠊཧ↷⏝࡜ࡋࡣᖖ࡟᭱᪂ࡢᢏ⾡ࢆᢕᥱࡋࠊࡇࡢ࣏࣮ࣞࢺࡣ୍⯡ⓗ࡚ࡢࡳ฼⏝ࡍ࡭ࡁ࡛࠶ࡿࠋࢥ࣑ࢵࢩࣙࢽࣥࢢࢹ

࡞ᡭ㡰᭩࡜ࡋ࡚ά⏝ࡍ࡭ࡁ࡛࠶ࡿࠋ

࣮ࢱࡢ௦⏝࡜ࡋ࡚ࡣ࡞ࡽ࡞࠸ࠋ

49

医学物理 第 33 巻 第 1 号

VII. まとめと勧告(10) ௵ពࡢ῝ࡉ࡟࠾ࡅࡿࠊ᭱኱↷ᑕ㔝࡛ࡢࢯࣇࢺ࢘
VII.B. ὀព࢙ࢵࢪ↷ᑕ㔝ࡢ㍈እ⥺㔞ࡢ⾲(1) 〇㐀ᴗ⪅ࡀᥦ౪ࡋࡓࢹ࣮ࢱ࡟౫Ꮡࡋ࡚ࡣ࠸ࡅ

(11) 㟁Ꮚ⥺ࢥ࣮ࣥࡢฟຊ⥺㔞ẚ࡜ᐇຠ⥺※㊥㞳࡞࠸ࠋࣅ࣮࣒ࢹ࣮ࢱࡣྠࡌ〇㐀ᴗ⪅ࡢྠࡌࣔࢹ

㸦effective SSD㸧ࣝࡢ⿦⨨㛫࡛ࡶ␗࡞ࡿࡓࡵࠊᖖ࡟⢭ᗘࢆ☜ㄆࡋ(12) 㟁Ꮚ⥺ࡢ PDD ⾲࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋ

(13) 㟁Ꮚ⥺࡜ගᏊ⥺ࡢ PDD ࡜ࣉࣟࣇ࢓࢖ࣝ࠿ࡽ⟬(2) ཷࡅධࢀヨ㦂ࡢࢹ࣮ࢱࡣࠊࢥ࣑ࢵࢩࣙࢽࣥࢢࢹ

ฟࡋࡓࠊᇶ‽↷ᑕ㔝࡛ࡢ➼⥺㔞᭤⥺ࠋ࣮ࢱࡢ௦⏝࡜ࡣ࡞ࡽ࡞࠸ࠋཷࡅධࢀヨ㦂ࡢࢹ࣮(14) ࡍ࡭࡚ࡢࢫ࢟ࣕࣥࢹ࣮ࢱࡢ༳ๅ≀ࢱࡣཧ↷ࡢࡳࢆ┠ⓗ࡜ࡋ࡚࠾ࡾࠊ㝈ᐃⓗ࡞ᩓ஘(15) ᪋タෆࡸ␗࡞ࡿ᪋タ࡛ࡢ㢮ఝ⿦⨨ࡢࢹ࣮ࢱ࡜

᮲௳ୗ࡛ᐃࡉࢀ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿࠋ

ࡢẚ㍑ࠋࡴࡸࡳ࡟ࢹ࣮ࢱࢆ౑⏝ࡋ࡚ࡣ࡞ࡽ࡞࠸

(3) ᳨ฟჾࡢ㍈᪉ྥ㸦ࢫ࢟ࣕࣥ᪉ྥ࡜᳨ฟჾࡢ㛗㍈ࡀࠊ࣋ࣥࢲ࣮ࡀᥦ౪ࡋࡓ͆golden͇ࢹ࣮ࢱ࡜ẚ࡜ࢆ୍⮴ࡉࡏࡿࡼ࠺࡞タ⨨㸧࡛ࢫ࢟ࣕࣥࡋ࡚ࡣ

㍑ࡍࡿࡇ࡜ࡣၥ㢟࡞࠸ࠋ(16) ࣋ࣥࢲ࣮ࡀᥦ౪ࡋࡓࢹ࣮ࢱ࡜ࡢẚ㍑⤖ᯝࠋࡓࡔ࠸ࡅ࡞࠸ࠋ(4) ࢫ࣒࣮ࢪࣥࢢࡲࡓࡣᩘᏛⓗࣇ࢕ࣝࢱࢆከ⏝ࡋࡋᥦ౪ࡉࢀࡓࢹ࣮ࢱࡣࠊཧ↷⏝࡜ࡋ࡚ࡢࡳ౑⏝࡚ࠊࢹ࣮ࢱࢆ㐣ᗘ࡟ຍᕤࡋ࡞࠸ࠋ
(5)ࡋࠊࢥ࣑ࢵࢩࣙࢽࣥࢢࢹ࣮ࢱࡢ௦⏝࡜ࡣ࡞ࡽ࡞

ᐃࢹ࣮ࢱ࡟ࡣ༑ศ࡟ὀពࢆᡶ࠺ࠋ௨㝆ࡢࢫ࢟ࣕࣥࢆᐇ᪋ࡍࡿ๓ࡲ࡛࡟ࠊࡍ࡭࡚ࡢ୙ලྜࡢၥ࠸ࠋ(17) ࡍ࡭࡚ࡢ㟁Ꮚࢹ࣮ࢱࠊゎᯒࡉࢀࡓࢹ࣮ࢱ࡜ࢫࣉ

㢟Ⅼࢆㄪᰝࡋ࡚ᢕᥱࡍࡿᚲせࡀ࠶ࡿࠋ(6) ᑡ࡞ࡃ࡜ࡶ୍᪥࡟୍ᗘࡣࠊỈࣇ࢓ࣥࢺ࣒ࡢỈᖹࣞࢵࢻࢩ࣮ࢺࡢࣂࢵࢡ࢔ࢵࣉࢆྲྀࡿࠋ
(18) ࣅ࣮࣒ࢹ࣮ࢱࡢྲྀᚓ᪉ἲ࡜ࡑࡢ᮲௳ࡢヲ⣽ࢆࠊࢆ☜ㄆࡍࡿࠋ

ሗ࿌᭩࡜ࡋ࡚ṧࡍࠋ

VII.C. ࢥ࣑ࢵࢩࣙࢽࣥࢢ࣏࣮ࣞࢺ

ㅰ㎡࣏࣮ࣞࢺࡢ⦅㞟࡜ᣦ᥹ࢆᇳࡗ࡚㡬࠸ࡓ Sun

 ࢥ࣑ࢵࢩࣙࢽࣥࢢ⤖ᯝࡢ࣏࣮ࣞࢺࡣࠊᑗ᮶ⓗ࡟᳨ドࡍࡿࡇ࡜ࡀ࡛ࡁࠊッゴࡢ㝿࡟ㄝ᫂㈐௵ࢆᯝࡓࡏࡿ

Nuclear ♫ࡢ James Pinkerton Ặ࡟ࠊཌࡃឤㅰࢆ⏦ࡋࡼ࠺࡟ࠊ᫂☜࠿ࡘලయⓗ࡟グ㏙ࡋࠊࡉࡽ࡟⨫ྡ࡜᪥ୖࡆࡲࡍࠋࡇࡢ࣏࣮ࣞࢺࢆᰯ㜀ࡋࡓ Ying Xiao Ặࠊ௜ࡶグ㍕ࡍࡿࡇ࡜ࢆ᥎ዡࡍࡿࠋDavid Followill Ặࠊ Per Halvorsen Ặࠊ Douglas Frye௨ୗࡣࠊࢥ࣑ࢵࢩࣙࢽࣥࢢ࣏࣮ࣞࢺ࡟グ㍕ࡋ࡞ࡅࢀẶࠊ࠾ࡼࡧ἞⒪≀⌮ጤဨ఍㸦TPC㸧ࡢ௚ࡢከࡃࡢጤ

ࡤ࡞ࡽ࡞࠸㡯┠ࡢ౛࡛࠶ࡿࠋ

ဨ࡟ឤㅰ⮴ࡋࡲࡍࠋ

(1) ṇᘧ࡞ࢥ࣑ࢵࢩࣙࢽࣥࢢ࣏࣮ࣞࢺࡣࠊ௨ୗࡢ㡯┠ࢆ᫂☜࡟ᴫㄝࡍࡿࠋ
㸦ᐃィ⏬ࡢ⠊ᅖ㸦┠ⓗ㸧ࠊᐃ㡯┠ࠊ᪉ἲࠊ౑⏝ࡋࡓ⿦⨨ࠊ⤖ᯝ࠾ࡼࡧ㐺ษ࡞ὀពࡀ᪋ࡉࢀࡓṇつ໬ᡭ㡰㸧(2) ࣮࢜ࣉࣥ↷ᑕ㔝ࡢගᏊ⥺ PDD ࡜ TMR ࡢ⾲(3) ࢙࢘ࢵࢪ↷ᑕ㔝ࡢගᏊ⥺ PDD ࡜ TMR ࡢ⾲(4) ගᏊ⥺ࡢฟຊಀᩘ㸦ScpࠊScࠊSp㸧ࡢ⾲(5) ↷ᑕ㔝࡜῝ࡉ࡟౫Ꮡࡍࡿ࢙࢘ࢵࢪಀᩘࡢ⾲(6) ࢯࣇࢺ࢙࢘ࢵࢪಀᩘࡢ⾲(7) ㏱㐣ಀᩘࡢ⾲(8) ௵ពࡢ῝ࡉ࡟࠾ࡅࡿࠊ᭱኱↷ᑕ㔝࡛ࡢ࣮࢜ࣉࣥ
↷ᑕ㔝ࡢ㍈እ⥺㔞ࡢ⾲(9) ௵ពࡢ῝ࡉ࡟࠾ࡅࡿࠊ᭱኱↷ᑕ㔝࡛ࡢ࢙࢘ࢵࢪ
↷ᑕ㔝ࡢ㍈እ⥺㔞ࡢ⾲

50

ཧ⪃ᩥ⊩
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K. Y. Quach, M. J. Butson, and P. E. Metcalfe, “Comparison ofeffective source-surface distances for electron beams derived frommeasurements made under different scatter conditions,” Australas.

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医学物理 第 33 巻 第 1 号⩻ヂ⪅㸦⩻ヂ㡰㸧⬥⏣ ᫂ᑦ㸦ᅜ❧ࡀࢇ◊✲ࢭࣥࢱ࣮୰ኸ⑓㝔 ᨺᑕ⥺἞⒪⛉㸧ᶫᮏ ៅᖹ㸦ࡀࢇ࣭ឤᰁ⑕ࢭࣥࢱ࣮㒔❧㥖㎸⑓㝔 ᨺᑕ⥺≀⌮ᐊ㸧Ἑෆ ᚭ 㸦༓ⴥ┴ࡀࢇࢭࣥࢱ࣮ ᨺᑕ⥺἞⒪㒊≀⌮ᐊ㸧ᑠᓥ ᚭ 㸦༓ⴥ┴ࡀࢇࢭࣥࢱ࣮ ᨺᑕ⥺἞⒪㒊≀⌮ᐊ⌧ ᇸ⋢┴❧ࡀࢇࢭࣥࢱ࣮ ᨺᑕ⥺἞⒪⛉㸧⩻ヂ༠ຊ⪅㸦஬༑㡢㡰㸧኱཭ ⤖Ꮚ㸦ࡀࢇ◊✲఍᭷᫂⑓㝔 ᨺᑕ⥺἞⒪㒊㸧
ᒸᮏ ⿱அ㸦ᅜ❧ࡀࢇ◊✲ࢭࣥࢱ࣮୰ኸ⑓㝔 ᨺᑕ⥺἞⒪⛉㸧㯮Ἑ ༓ᜨ㸦㡰ኳᇽ኱Ꮫ኱Ꮫ㝔་Ꮫ◊✲⛉ ⮫ᗋ⭘⒆Ꮫ㸧బࠎᮌᾈ஧㸦☬⏣ᕷ❧⥲ྜ⑓㝔 ་⒪ᢏ⾡㒊་Ꮫ≀⌮ᐊ㸧㎮ᕫ ኱స㸦኱㜰ᕷ❧኱Ꮫ་Ꮫ㒊㝃ᒓ⑓㝔 ୰ኸᨺᑕ⥺㒊⌧ 㒔ᓥᨺᑕ⥺⛉ࢡࣜࢽࢵࢡ㸧⸨⏣ ᖾ⏨㸦ᮾ໭኱Ꮫ኱Ꮫ㝔་Ꮫ⣔◊✲⛉ ᨺᑕ⥺἞⒪⛉㸧ᐑୗ ஂஅ㸦ྠឡグᛕ⑓㝔 ᨺᑕ⥺⛉⌧ ᮾி㒔೺ᗣ㛗ᑑ་⒪ࢭࣥࢱ࣮ ᨺᑕ⥺デ⒪⛉㸧ᐑ㒊 ⤖ᇛ㸦ி㒔኱Ꮫ኱Ꮫ㝔་Ꮫ◊✲⛉ ᨺᑕ⥺⭘⒆Ꮫ࣭⏬ീᛂ⏝἞⒪Ꮫ㸧
翻訳者代表
脇田

明尚（わきた．あきひさ）

国立がん研究センター中央病院

医学物理士。

現在の職場では主に治療装置の品質管理、高精度放射線治療計画の立案などを行っている。
E-mail: awakita@ncc.go.jp

56Jpn. J. Med. Phys. Vol. 33 No. 1 (2013)

American Association of Physicists in Medicine
One Physics Ellipse
College Park, MD 20740-3846(301) 209-3350
Fax (301) 209-0862
http://www.aapm.org

Office of the Executive Director
Angela R. Keyser
Phone: 301-209-3385 Fax: 301-209-0862
E-mail: akeyser@aapm.org

VIA E-MAIL
Akihisa Wakita
Medical Physicist
Division of Radiation Oncology
National Cancer Center Hospital
Tsukiji, Tokyo 104-0045
JAPAN
November 7, 2011
Dear Mr. Wakita
The American Association of Physicists in Medicine (AAPM) hereby grants permission to theJapan Society of Medical Physics to translate the following AAPM publication into Japanese andpost on their website:
Das, I., et al. “Accelerator beam data commissioning equipment and procedures: Reportof the TG-106 of the Therapy Physics Committee of the AAPM”. Med. Phys. 35(9)4186-4216 (2008).
Please let us know if you have any questions or require additional information.
Sincerely,

Angela R. Keyser

The Association’s Scientific Journal is MEDICAL PHYSICS
Member Society of the American Institute of Physics and the International Organization of Medical Physics

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