Jpn. J. Med. Phys. Vol. 33 No. 1: 16–57 (2013) 解説 ་⒪⏝ຍ㏿ჾ࠾ࡅࡿࢥ࣑ࢵࢩࣙࢽࣥࢢࡢᶵჾᡭ㡰 ⡿ᅜ་Ꮫ≀⌮Ꮫ࣭⒪≀⌮ጤဨࢱࢫࢡࢢ࣮ࣝࣉ 106 ࣏࣮ࣞࢺ ᪥ᮏㄒヂ ⩻ヂ⪅ ⬥⏣ ᫂ᑦ㸦ᅜ❧ࡀࢇ◊✲ࢭࣥࢱ࣮୰ኸ㝔 ᨺᑕ⥺⒪⛉㸧 ᶫᮏ ៅᖹ㸦ࡀࢇ࣭ឤᰁࢭࣥࢱ࣮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ࡶࡵࡊࡲࡋ࠸ᢏ⾡㠉᪂ࢆ㐙ࡆ࡚࠾ࡾࠊᮏ㑥࡛ࡶࠊᙉᗘኚㄪᨺ ᑕ⥺⒪ࠊᐃᨺᑕ⥺⒪ࢆࡣࡌࡵࡍࡿ㧗⢭ᗘᨺᑕ⥺⒪ࡀከࡃࡢタ࡛ᐇࡉࢀࡿࡼ࠺࡞ࡗ࡚ࡁ࡚࠸ࡿࠋ ⌧ᅾ࡛ࡣࠊࡇࢀࡽࡢ㧗⢭ᗘᨺᑕ⥺⒪ࢆྵࡴࢇࡢ⒪ィ⏬ࡣ 3 ḟඖ⒪ィ⏬⨨ࢆ⏝࠸࡚❧ࡉࢀ࡚࠾ ࡾࠊ⒪ィ⏬⨨࠾ࡅࡿ⥺㔞ィ⟬ࡢ࣮࣋ࢫ࡞ࡿ⒪⨨ࡢࣅ࣮࣒ࢹ࣮ࢱࡢṇ☜ࡉࡣࠊᝈ⪅ࡉࢇᢞࡍࡿ ⥺㔞ࡢṇ☜ࡉ┤⤖ࡋ࡚࠸ࡿࠋ ࡑࡢࡼ࠺࡞୰ࠊ2008 ᖺ⡿ᅜ་Ꮫ≀⌮Ꮫࡼࡾࠊࣅ࣮࣒ࢹ࣮ࢱ ᐃ㛵ࡍࡿࢱࢫࢡࢢ࣮ࣝࣉ࣏࣮ࣞࢺ 106 㸦TG-106㸧ࡀⓎหࡉࢀࡓࠋTG-106 ࡣࠊࣜࢽࢵࢡᑟධ࠾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⏝ࡍࡿࡇࡶྍ⬟࡛࠶ࡿࠋ ᡃࠎࡣࠊࡇࡢ TG-106 ࡀᮏ㑥࡛ࡶ᭷ຠά⏝ࡉࢀࡿࡼ࠺ࠊ⮫ᗋ་Ꮫ≀⌮◊✲࠾ࡼࡧ᪥ᮏ་Ꮫ≀⌮Ꮫㄢ㢟 ู◊✲⌜ࠕ㧗⢭ᗘእ㒊ᨺᑕ⥺⒪ࡢရ㉁ಖド࣭ရ㉁⟶⌮ࢩࢫࢸ࣒ࡢᵓ⠏ࠖ㸦◊✲௦⾲⪅ ᒸᮏ⿱அඛ⏕㸸ᅜ❧ ࡀࢇ◊✲ࢭࣥࢱ࣮୰ኸ㝔 ᨺᑕ⥺⒪⛉㸧ࡢ࣓ࣥࣂ࣮ࡢ༠ຊࡢࡶࠊ⩻ヂసᴗࢆ㐍ࡵࠊࡇࡢᗘࠕ་Ꮫ≀⌮ࠖ ㄅゎㄝ࠸࠺ᙧ࡛ฟ∧ࡢᶵࢆᚓࡓࠋ࡛ࡁࡿࡔࡅ㏲ㄒヂࢆᚰࡅࡘࡘࡶࠊពࡢ㏻ࡾࡸࡍ࠸᪥ᮏㄒ࡞ࡿࡼ ࠺⪃៖ࡋࡓࡘࡶࡾ࡛࠶ࡿࡀࠊㄞࡳ࡙ࡽ࠸⟠ᡤࡀぢཷࡅࡽࢀࡓሙྜࡣࡈᢎ࠸ࡓࡔࡅࢀࡤᖾ࠸࡛࠶ࡿࠋཎᩥ㛵 ࡋ࡚ࡣࠊhttp://www.aapm.org/pubs/reports/ ࡽࣇ࣮࡛ࣜࢲ࣮࢘ࣥࣟࢻྍ⬟࡞ࡢ࡛ࠊㄞ⪅ࡢᚲせᛂࡌ࡚ཎᩥࡶ ཧ↷࠸ࡓࡔࡅࢀࡤᛮ࠺ࠋ ࡇࡢ TG-106 ࣏࣮ࣞࢺ᪥ᮏㄒヂࡀࠊከࡃࡢᨺᑕ⥺⒪タ࡛᭷ຠά⏝ࡉࢀࠊᏳ࡛㧗⢭ᗘ࡞⒪ࢆ⾜࠺ࡓ ࡵࡢ୍ຓ࡞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 Lowenstein Radiological 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‽࡞ࡿࡶࠊ᭱⤊ⓗࡣ⒪ィ⏬⨨㸦TPS㸧࡛⏝࠸ࡽࢀࡿࡓ ࡵࠊࢹ࣮ࢱࡢ㞟ࡣ㧗࠸⢭ᗘ࡛⾜ࢃࢀࡿᚲせࡀ࠶ࡿࠋࡑ࠺ࡍࡿࡇ࡛ᝈ⪅⒪࠾ࡅࡿ⥺㔞ㄗᕪࢆపῶࡋࠊࡦ ࠸࡚ࡣᨺᑕ⥺⒪ࡢຠᯝࡢపୗࢆ㜵ࡄࡇࡀ࡛ࡁࡿࠋࣅ࣮࣒ࢹ࣮ࢱࡢࢥ࣑ࢵࢩࣙࢽࣥࢢࡣ㐺ษ࡞▱㆑ᶵჾࢆ ⏝࠸࡚⾜ࢃࢀࡿࡁ࡛࠶ࡾࠊ ᐃ⪅ࡼࡗ࡚␗࡞ࡿ⤖ᯝࢆ⏕ࡴࡇࡀ࠶ࡗ࡚ࡣ࡞ࡽ࡞࠸ࠋࡇࢀࡽࢆ㐩ᡂࡍࡿࡓ ࡵ American Association of Physicists in Medicine㸦AAPM㸧ࡢ⒪≀⌮ጤဨ㸦Therapy Physics Committee㸧 ࠾࠸࡚ࠊࣜࢽࢵࢡࡢ≀⌮ⓗࢥ࣑ࢵࢩࣙࢽࣥࢢྠᵝࠊᐇ㊶ⓗ࡞ࣅ࣮࣒ࢹ࣮ࢱ ᐃࢆ᳨ウࡍࡿࡇࢆ┠ⓗ ࡋ࡚ࢱࢫࢡࢢ࣮ࣝࣉ㸦TG㸧106 ࡀ⤌⧊ࡉࢀࡓࠋࡇࡢ࣏࣮ࣞࢺ࡛ࡣࠊ㐺ษ࡞ࣇࣥࢺ᳨࣒ฟჾࡢ㑅ᢥࠊࢹ࣮ࢱ ᐃࡢࡓࡵࡢࣇࣥࢺ࣒ࡢࢭࢵࢺࢵࣉἲ㸦ࢫ࢟ࣕࢽࣥࢢࣀࣥࢫ࢟ࣕࢽࣥࢢ୧᪉㸧 ࠊගᏊ⥺࣭㟁Ꮚ⥺ࡢලయ ⓗ࡞ࣅ࣮࣒ࣃ࣓࣮ࣛࢱྲྀᚓἲ ᐃㄗᕪࡢῶᑡ᪉ἲ㸦<1%㸧ࠊࣅ࣮࣒ࢹ࣮ࢱࡢຍᕤἲ࠾ࡼࡧṇ☜࡞ࣉࣟࣇ ࣝࢆᚓࡿࡓࡵࡢ᳨ฟჾࢧࢬࢥ࣮ࣥ࣎ࣜࣗࢩࣙࣥ࡞㛵ࡍࡿ࢞ࢻ່ࣛࣥ࿌ࢆᥦ౪ࡍࡿࠋࡲࡓࠊࡇࡢ TG-106 ࡛ࡣගᏊ⥺࣭㟁Ꮚ⥺ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ࠾ࡅࡿࣔࣥࢸ࢝ࣝࣟࢩ࣑࣮ࣗࣞࢩࣙࣥἲࡢ㏆ᖺࡢࢺࣞࣥࢻ 㛵ࡋ࡚ࡶ⡆₩ㄽࡎࡿࠋࡇࡢ࣏࣮ࣞࢺグ㍕ࡉࢀࡓᡭἲࡣ་Ꮫ≀⌮ኈࡗ୍࡚㐃ࡢࣅ࣮࣒ࢹ࣮ࢱࡢ ᐃࡸࠊ ⮫ᗋ⏝๓࠾ࡼࡧᐃᮇⓗ࡞ QA ࠾ࡅࡿࢹ࣮ࢱࡢ᳨ドࢆ⾜࠺࠶ࡓࡗ࡚ᡭຓࡅ࡞ࡿࡣࡎ࡛࠶ࡿࠋᐇ㊶⌮ㄽ ࢆ⤌ࡳྜࢃࡏࡿࡇ࡛ࠊࡇࡢ࣏࣮ࣞࢺࡣࣅ࣮࣒ࢹ࣮ࢱࢥ࣑ࢵࢩࣙࢽࣥࢢࡢ᪂ࡋ࠸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࿘Ἴࣀࢬࡢᖸ΅ I.B. ⫼ᬒ III.F. ࢹ࣮ࢱࣇࣝ I.B.1. ࢹ࣮ࢱࢥ࣑ࢵࢩࣙࢽࣥࢢࡢᚲせᛶ III.F.1. ࢹ࣮ࢱࣇࣝࡢᵓᡂ I.B.2. ࣅ࣮࣒ࢥ࣑ࢵࢩࣙࢽࣥࢢ㛵ࡍࡿၥ㢟 III.F.2. ࣇࣝࡢྡ๓ I.B.3. ࡇࡢࢱࢫࢡࢢ࣮ࣝࣉࡘ࠸࡚ I.B.4. ࢥ࣑ࢵࢩࣙࢽࣥࢢࡢసᴗ㔞 II. ࣇࣥࢺ࣒ࡢᮦ㉁⏝ἲࠊ᳨ฟჾ II.A. ࣇࣥࢺ࣒ᮦ㉁ IV. ගᏊ⥺ࡢࣅ࣮࣒ࢹ࣮ࢱ IV.A. ගᏊ⥺ࢫ࢟ࣕࣥࢹ࣮ࢱ ᐃ IV.A.1. ῝㒊⥺㔞 IV.A.2. ⤌⧊᭱⥺㔞ẚ࣭⤌⧊ࣇࣥࢺ࣒⥺㔞 II.B. ࣇࣥࢺ࣒ࡢᑍἲ II.C. ᅛయࣇࣥࢺ࣒ IV.A.3. ⾲㠃⥺㔞ࣅࣝࢻࢵࣉ㡿ᇦ II.D. ࣅࣝࢻࢵࣉ࢟ࣕࢵࣉ IV.A.4. ࣅ࣮࣒ࣉࣟࣇࣝ II.E. ᳨ฟჾ II.E.1. ྛ᳨ฟჾࡢ᭷⏝ᛶ IV.B. MLC ࢹ࣮ࢱ IV.C. ගᏊ⥺࣏ࣥࢺ⥺㔞ࢹ࣮ࢱ II.E.2. ᳨ฟჾࡢ✀㢮 IV.C.1. ᩓಀᩘ 㸦Scp㸧 II.E.3. ᳨ฟჾࡢ㑅ᢥ IV.C.2. ✵୰ฟຊಀᩘ 㸦Sc㸧 II.E.4. ᳨ฟჾࡢᛂ⟅⿵ṇ IV.C.3. ࣇࣥࢺ࣒ᩓಀᩘ 㸦Sp㸧 III. ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢࢭࢵࢺࢵࣉ III.A. ࢫ࢟ࣕࢼࡢ᳨ド☜ㄆ III.A.1. ࢫ࢟ࣕࢽࣥࢢ㸦ࣇ࣮ࣝࢻ㸧⥺㔞ィ ࣜࣇࣞࣥࢫ⥺㔞ィ III.A.2. ࢣ࣮ࣈࣝࠊࢥࢿࢡࢱࠊࢲࣉࢱ III.A.3. 㟁ィ III.B. ࢫ࢟ࣕࢽࣥࢢ⏝Ỉࢱࣥࢡ III.B.1. ࣏ࢪࢩࣙࢽࣥࢢࣛ࣋ࣜࣥࢢ IV.C.4. ࢙࢘ࢵࢪಀᩘ IV.C.5. ࢺࣞಀᩘ IV.C.6. ᑠ↷ᑕ㔝࡛ࡢ⪃៖ V. 㟁Ꮚ⥺ V.A. 㟁Ꮚ⥺ࢫ࢟ࣕࣥࢹ࣮ࢱ ᐃ V.A.1. ῝㒊⥺㔞 V.A.2. ࣉࣟࣇࣝ V.B. 㟁Ꮚ⥺࣏ࣥࢺ⥺㔞ࢹ࣮ࢱ III.B.2. ࢫ࢟ࣕࢼࡢ㥑ື V.B.1. ࢥ࣮ࣥಀᩘ III.B.3. ࢫ࢟ࣕࢽࣥࢢࡢ᪉ྥ V.B.2. ࢝ࢵࢺ࢘ࢺಀᩘ III.C. ࢫ࢟ࣕࣥࡢ㥑ືᶵᵓືࡁ V.B.3. ௬/ᐇຠ⥺※⨨ III.C.1. 㓄ิᆺ᳨ฟჾࡢ㔜㔞 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. ࢻࣛࣛࣥ V.B.4. ࣔࣥࢸ࣮࢝ࣝࣟ࣋ࢫࡢ⥺㔞ィ⟬ࡢࡓࡵ ࡢࢹ࣮ࢱ VI. ࣅ࣮࣒ࢹ࣮ࢱࡢຍᕤ VI.A. ࢹ࣮ࢱࡢຍᕤ᧯స VI.B. ࢫ࣒࣮ࢪࣥࢢ࣭࣑࣮ࣛࣜࣥࢢ࠾ࡼࡧࢧ࣐ࣛ ࢪࣥࢢ III.D.2. ࢛࣮࢘ࢱࣛࣥ VI.B.1. ᩘᏛ㛵ᩘࣇࣝࢱ 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 ẚ 㸦TMR/TPR㸧 VI.C. ࣀࣥࢫ࢟ࣕࣥࢹ࣮ࢱࡢຍᕤ VII. ࡲࡵ່࿌ 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. ┠ⓗ ࠸࠸࠺ࡇ࡛࠶ࡿࠋ࠼ࡤࠊྠࡌබ⛠࢚ࢿࣝࢠ࣮ ࣅ࣮࣒ࢹ࣮ࢱࡢࢥ࣑ࢵࢩࣙࢽࣥࢢࡣࠊ㐺ษ࡞▱㆑ ࢆࡶࡘ⨨㛫࡛ࡶࠊࣅ࣮࣒ࣃ࣓࣮ࣛࢱᕪࡀ⏕ࡌࡿ 3-5 ࠋ➨ࠊࣜࢽࢵࢡࡢᑟ ᶵჾᇶ࡙࠸࡚⾜࠸ࠊ ᐃ⪅ࡸࢫ࢟ࣕࢽࣥࢢࢩࢫ ࡇࡀሗ࿌ࡉࢀ࡚࠸ࡿ ࢸ࣒౫Ꮡࡋ࡚ࡣ࡞ࡽ࡞࠸ࠋ ᐃ⪅ࡼࡿࢹ࣮ࢱࡢ ධ࠾ࡼࡧཷࡅධࢀࡢ㝿ࡢྛタ࠾ࡅࡿኚ᭦㸦ࣅ࣮ ┦㐪ࡣྍ⬟࡞㝈ࡾᑠࡉࡃࡍࡿᚲせࡀ࠶ࡿ㸦<1%㸧 ࠋ ࣒࢚ࢿࣝࢠ࣮ࡢኚ᭦ࡸࠊࢫࢸࣜࣥࢢࡢኚ᭦ࡼࡿ ࡇࢀࢆ㐩ᡂࡍࡿࡓࡵࠊࡇࡢ࣏࣮ࣞࢺ࡛ࡣࠊࣇࣥࢺ ࣉࣟࣇࣝࡢኚ࡞㸧ࡣ͆golden͇ࣅ࣮࣒ࢹ࣮ ࣒ࡢࢭࢵࢺࢵࣉࠊ ᐃᢏ⾡ࠊࣇࣥࢺ᳨࣒ฟჾ ࢱࡣᫎࡉࢀ࡞࠸ࠋ➨୕ࠊࢯࣇࢺ࢙࢘ࢵࢪࡢࣅ ࡢ㑅ᢥࠊㄗᕪࡢせᅉ࠾ࡼࡧලయⓗ࡞ගᏊ⥺࣭㟁Ꮚ⥺ ࣮࣒≉ᛶࡣ jaw ࡢ㏿ᗘࣃ࣓࣮ࣛࢱࡼࡾኚࡋࠊྛ ࣅ࣮࣒ࢹ࣮ࢱ ᐃࡢࡓࡵࡢ່࿌ࢆ⾜࠸ࠊࣅ࣮࣒ࢹ࣮ タ࡛ࡢ㏿ᗘࡢ┦㐪ࡀࢯࣇࢺ࢙࢘ࢵࢪࡢࣅ࣮࣒ࣉ ࢱࡢࢥ࣑ࢵࢩࣙࢽࣥࢢࢆᐜ᫆ࡍࡿࡇࢆ┠ⓗ ࣟࣇࣝᙳ㡪ࢆ࠼࠺ࡿࠋ➨ᅄࠊ ͆golden͇ࢹ ࡋ࡚࠸ࡿࠋ ࣮ࢱࡀಶࠎࡢࢳ࢙ࢵࢡ࠾࠸࡚チᐜ࡛ࡁࡿ⤖ᯝࡔ ࡗࡓࡋ࡚ࡶࠊ⮫ᗋࢭࢵࢺࢵࣉ࠾࠸࡚」ྜⓗ࡞ I.B. ⫼ᬒ ࢚࣮ࣛࡀ⏕ࡲࢀࠊ⤖ᯝࡋ࡚チᐜ࡛ࡁ࡞࠸ྍ⬟ᛶࡀ I.B.1. ࢹ࣮ࢱࢥ࣑ࢵࢩࣙࢽࣥࢢࡢᚲせᛶ ࠶ࡿࠋ᭱ᚋࠊࣅ࣮࣒ࢹ࣮ࢱࢥ࣑ࢵࢩࣙࢽࣥࢢࢆ⾜ ᨺᑕ⥺⒪ࡢຠᯝࡣࠊᝈ⪅ᢞࡉࢀࡿ⥺㔞ࡢ⢭ ࠺ࡇࡀࣜࢽࢵࢡࡢᚭᗏⓗ࡞ࢳ࢙ࢵࢡࡘ࡞ࡀ ᗘ┤᥋㛵㐃ࡋࠊࡑࢀࡽࡣ⒪ィ⏬ࡢࣉࣟࢭࢫ ࡾࠊၥ㢟ࢆⓎぢ࡛ࡁࡿྍ⬟ᛶࡀ࠶ࡿࡢᑐࡋࠊ ⏝ࡍࡿࣅ࣮࣒ࢹ࣮ࢱࡢ⢭ᗘ౫Ꮡࡍࡿࠋࡇࢀࡽࡢࢹ 㸦͆golden͇ࢹ࣮ࢱᑐࡍࡿ㸧ᒁᡤⓗ࡞ࢳ࢙ࢵࢡ࡛ࡣ ࣮ࢱࡣࣜࢽࢵࢡࡢᑟධྲྀᚓࡉࢀࡿࠋࡲࡓࠊࡑ Ⓨぢ࡛ࡁ࡞࠸ࡇࡶ⪃࠼ࡽࢀࡿ࠸࠺ࡇ࡛࠶ࡿࠋ ࡢࢹ࣮ࢱࡣᇶ‽್ࡋ࡚ᢅࢃࢀࠊ་Ꮫ≀⌮ኈࡣ 1 ࡋࡋ࡞ࡀࡽࠊᑡ࡞ࡃࡶ͆golden͇ࢹ࣮ࢱࡣࣘ TG-40 グ㍕ࡉࢀ࡚࠸ࡿࡼ࠺ࠊᐃᮇⓗ࣐ࢩࣥ ࣮ࢨ࣮ࡀྲྀᚓࡋࡓࣅ࣮࣒ࢹ࣮ࢱࡢ᳨ドᑐࡍࡿ㠀 ࣃ࣓࣮ࣛࢱࡀኚࡋ࡚࠸࡞࠸ࡇࢆ☜ㄆࡍࡁ࡛ ᖖඃࢀࡓ QA ࡢཧ⪃ࢹ࣮ࢱ࡞ࡿࠋࡇࢀࡽࡢࢹ࣮ ࠶ࡿࠋࡲࡓࠊ⒪ィ⏬⨨㸦TPS㸧ࡢィ⟬ࣝࢦࣜ ࢱࡣ MD Anderson Cancer Center ࠾ࡅࡿᨺᑕ⥺≀ ࢬ࣒ࢆኚ᭦ࡍࡿሙྜ࡞ࠊTPS ఱࡽࡢኚࡀ࠶ ⌮ࢭࣥࢱ࣮㸦Radiological Physics Center㸧ࡽྲྀᚓྍ 2 ࡗࡓሙྜ࡛ࡣࠊࢹ࣮ࢱࡢ㏣ຍࡀᚲせ࡛࠶ࡿ ࠋ ࣜࢽࢵࢡࡢ〇㐀ᕤ⛬ࡀᏳᐃࡍࡿࡘࢀ࡚ࠊ〇㐀 ⬟࡛࠶ࡾ 6-8ࠊ࣮ࣘࢨ࣮ࡣ⮬タࡢࢹ࣮ࢱタࡢ ࢹ࣮ࢱࢆẚ㍑ࡋࠊྜ⌮ⓗ࡞⠊ᅖ୍࡛⮴ࡍࡿ☜ㄆࡍ ᴗ⪅ࡣྠ୍ࡢࣅ࣮࣒≉ᛶࢆ♧ࡍࡼ࠺⒪⨨ࢆᶆ ࡿࡇࡀ࡛ࡁࡿࠋࣔࣥࢸ࢝ࣝࣟࢩ࣑࣮ࣗࣞࢩࣙࣥࡶ ‽ࡋࡼ࠺ࡍࡿࠋTPS ᚲせ࡞ࢇࠊ࠶ࡿ࠸ ࡲࡓࡼ࠸ᶆ‽ࢹ࣮ࢱࢆ࠼ࡿࠋࡋࡋ࡞ࡀࡽࣔࣥࢸ ࡣࡍ࡚ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢࡉࢀࡓࣅ࣮࣒ࢹ࣮ࢱ ࢝ࣝࣟࢩ࣑࣮ࣗࣞࢩࣙࣥࡼࡿࢹ࣮ࢱࡢ᳨ドࡣࠊ ࡀ͆golden͇ࣅ࣮࣒ࢹ࣮ࢱࡋ࡚࠼ࡽࢀࡿሙྜࡶ ᇶ‽࡞ࡿ ᐃࡀᚲせ࡞ࡿ 9-13ࠋ ࠶ࡿࠋࣜࢽࢵࢡྠࡌ࣋ࣥࢲ࣮ࡀ TPS ࢆᥦ౪ࡋ࡚ ࡇࡢ࣏࣮ࣞࢺ࡛ࡣࣜࢽࢵࢡࡢࢥ࣑ࢵࢩࣙࢽࣥ ࠸ࡿሙྜࠊ ͆golden͇ࣅ࣮࣒ࢹ࣮ࢱࡣࡍ࡛ TPS ࢢ᥎ዡࡍࡿ ᐃ㡯┠ࡘ࠸࡚ࡣグ㍕ࡋ࡚࠸࡞ Ⓩ㘓ࡉࢀ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿࠋࡇࡢࡼ࠺࡞ሙྜࠊࣅ ࠸ࡀࠊᑡ࡞ࡃࡶ௨ୗࡢ㡯┠ࡢࢹ࣮ࢱࡣྲྀᚓࡍࡿᚲ ࣮࣒ࢥ࣑ࢵࢩࣙࢽࣥࢢࡢ㝿ࠊ࣮ࣘࢨ࣮ࡣᚲせ࡞ࡍ せࡀ࠶ࡿࠋ ࡚ࡢࢹ࣮ࢱࢆ ᐃࡍࡿࠊ࠶ࡿ࠸ࡣⓏ㘓ࡉࢀ࡚࠸ ࡿࢹ࣮ࢱࢆὀព῝ࡃ᳨ドࡍࡿࢆ㑅ᢥࡍࡿࡇࡀ x ගᏊ⥺͐῝㒊㔞ⓒศ⋡㸦PDD㸧ࠊ࣮࢜ࣉࣥ࠾ࡼ ࡛ࡁࡿࠋࡕࡽࢆ㑅ᢥࡍࡿࡇࡀ㐺ᙜࡣࠊࣜࢽ ࡧ࢙࢘ࢵࢪ↷ᑕ㔝ࡢ」ᩘࡢ῝ࡉ࠾ࡅࡿࣉࣟ ࢵࢡࡸ TPS ࡢࣔࢹࣝࠊ⮫ᗋ⏝⪏࠼࠺ࡿ⢭ᗘࢆᣢ ࣇࣝ㸦in-plane ࠾ࡼࡧ cross-plane㸧ࠊMLC ࡗ࡚࠸ࡿ࡞ࠊ࠸ࡃࡘࡢせᅉ౫Ꮡࡍࡿࡔࢁ࠺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➨୍ ಀᩘࠊᩓಀᩘࠊࢺࣞಀᩘࠊ࢙࢘ࢵࢪಀ ࠊ〇㐀ᕤ⛬࠾࠸࡚ࡍ࡚ࡢࣜࢽࢵࢡࡀ⮫ᗋ ᩘࠋ 19 医学物理 第 33 巻 第 1 号 x I. はじめに 㟁Ꮚ⥺͐PDD, ࣉࣟࣇࣝ, ࢥ࣮ࣥಀᩘࠊ࢝ ࢵࢺ࢘ࢺಀᩘࠊ௬⥺※⨨ࠋ ࢥ࣑ࢵࢩࣙࢽࣥࢢࡣㄆᐃࡉࢀࡓ་Ꮫ≀⌮ኈࡼ ࡗ࡚⾜ࢃࢀࡿᚲせࡀ࠶ࡿࠋࡇࡢ࣏࣮ࣞࢺグ㍕ࡉࢀ ࡓᡭἲࡣࣅ࣮࣒ࢹ࣮ࢱࡢ ᐃ࠾ࡼࡧ⮫ᗋ⏝๓ࡢ ࢹ࣮ࢱ☜ㄆࡸᐃᮇⓗQAࡢᇶ‽ࢹ࣮ࢱࢆ ᐃࡍࡿ࠺ ࠼࡛ᡭຓࡅ࡞ࡿࡔࢁ࠺ࠋTG-53 2 ࡛グ㍕ࡉࢀ࡚࠸ ࡿTPS㛵㐃ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢヂ⪅ὀ 1㛵ࡋ࡚ࡶ⪃ ៖ࡍࡁ࡛࠶ࡿࠋ I.B.2. ࣅ࣮࣒ࢥ࣑ࢵࢩࣙࢽࣥࢢ㛵ࡍࡿၥ㢟 ከࡃࡢࣅ࣮࣒ࢹ࣮ࢱ ᐃࡣẚ㍑ⓗ༢⣧࡛࠶ࡿࡀࠊ ⏝ࡍࡿ᳨ฟჾࢩࢫࢸ࣒ࣇࣥࢺ࣒ࡼࡗ࡚⤖ ᯝࡀࡁࡃኚࡍࡿࡇࡀ࠶ࡿࠋ᳨ฟჾࡣࢧࢬ 㸦ᶆ‽ᆺࠊ࣑ࢽᆺࠊ࣐ࢡࣟᆺ㸧ࠊࢱࣉ㸦㟁㞳⟽࣭ ༙ᑟయ࡞㸧ࠊᙧ≧㸦ᣦ㢌ᙧࠊ⌫ᙧࠊᖹ⾜ᖹᯈᙧ㸧 ࡞ከࡃࡢ㑅ᢥ⫥ࡀ࠶ࡾࠊ㐺ษ࡞᳨ฟჾࡢ㑅ᢥࡣ ᅔᝨࡉࡏࡽࢀࡿࠋࡶࡋ㐺ษ࡞᳨ฟჾࢆ㑅ᢥࡋࡓሙ ྜࠊ ᐃࡋࡓࣅ࣮࣒ࢹ࣮ࢱࡢ㉁ࡀపୗࡍࡿሙྜࡶ࠶ ࡿࠋ࠼ࡤ Fig.1 ࡣ 6 MV ࣅ࣮࣒ࡢᑠ↷ᑕ㔝ࠊᇶ‽ ↷ᑕ㔝㸦1010 cm2㸧ࠊ↷ᑕ㔝ࡢ PDD ࢆᵝࠎ࡞᳨ ฟჾ࡛ྲྀᚓࡋࡓ⤖ᯝ࡛࠶ࡿࠋ᳨ฟჾࡼࡗ࡚ᑠ↷ᑕ 㔝࠾ࡼࡧ↷ᑕ㔝࡛チᐜ࡛ࡁ࡞࠸┦㐪ࡀ⏕ࡌ࡚࠸ ࡿࠋ 〇㐀ᴗ⪅ࡣཷࡅධࢀヨ㦂ࡢ㝿࢞ࢻࣛࣥ チᐜ⠊ᅖࢆᥦ♧ࡍࡿࠋࡋࡋࠊ⒪⨨ࡢࢥ࣑ࢵࢩ ࣙࢽࣥࢢࡣྛタࡢ་Ꮫ≀⌮ኈࡀ㈐௵ࢆࡶࡘᚲせ ࡀ࠶ࡿࠋ㐣ཤࡢࢱࢫࢡࢢ࣮ࣝࣉ 14, 15 ࡣཷࡅධࢀヨ㦂 ᑐࡍࡿ࢞ࢻࣛࣥࢆ♧ࡋ࡚࠸ࡿࡀࠊࣅ࣮࣒ࢹ࣮ ࢱࡢࢥ࣑ࢵࢩࣙࢽࣥࢢᑐࡋ࡚ࡣゝཬࡋ࡚࠸࡞࠸ࠋ ཷࡅධࢀヨ㦂ࢥ࣑ࢵࢩࣙࢽࣥࢢ㛵ࡍࡿ᭱㏆ࡢ ᩥ⊩ 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ࢥ࣑ࢵ ࢩࣙࢽࣥࢢࡘ࠸࡚ࠊㄗࡗࡓㄆ㆑ࡀ࠶ࡿࠋཷࡅධࢀ ヨ㦂ࡣࠊ〇㐀ᴗ⪅ࡀᐃࡵࡿ࢞ࢻࣛࣥᚑࡗ࡚⾜ ࢃࢀࠊࣅ࣮࣒ࢹ࣮ࢱࡢ☜ㄆࡣࡈࡃࢃࡎ࡛࠶ࡿࠋࡑ ࢀᑐࡋ࡚ࠊࢥ࣑ࢵࢩࣙࢽࣥࢢࡣࠊࡍ࡚ࡢࣅ࣮࣒ ࢹ࣮ࢱࢆྲྀᚓࡋࠊࡑࡢࢹ࣮ࢱࡀᝈ⪅⒪⏝࠸ࡽࢀ ࡿࠋ⮫ᗋ⏝ࡉࢀࡿ⥺㔞ࢹ࣮ࢱࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ 㛵ࡋ࡚ࡣࢇᩥ᭩ࡉࢀࡓሗࡀ࡞࠸ࡢࡀ ⌧≧࡛࠶ࡿࠋ I.B.3. ࡇࡢࢱࢫࢡࢢ࣮ࣝࣉࡘ࠸࡚ ヂ⪅ὀ1 ụ⏣⌜ࡼࡿヂࡀ JSMP ࣮࣒࣮࣍࣌ࢪୖ බ㛤ࡉࢀ࡚࠸ࡿࠋ 20 ࡇࡢࢱࢫࢡࢢ࣮ࣝࣉࡣࠊࣜࢽࢵࢡࡢࢥ࣑ࢵࢩࣙ 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 for electron 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 or star 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 dose ࢽࣥࢢ㛵ࡍࡿ≀⌮ⓗ࡞㡯ࡘ࠸᳨࡚ウࡋࠊ㐺 ࣮ࣝࣉࡽࡑࢀࡽࡢࢱࢫࢡࢢ࣮ࣝࣉࡢ࣏࣮ࣞࢺ ษ࡞᳨ฟჾࠊࣇࣥࢺ࣒ࠊ࠾ࡼࡧ ᐃ᪉ἲࡢ࢞ࢻ ┤᥋ཧ↷ࢆ⾜ࡗ࡚࠸ࡿࠋTG-106 ࡣ᳨ฟჾࠊࣇࣥ ່ࣛࣥ࿌ࢆ♧ࡍࡇࡼࡾࠊ ᐃㄗᕪࢆs1% ࢺ࣒ࠊ ᐃᶵჾ㸦㟁ィ㸧 ࠊၟ⏝ࢩࢫࢸ࣒ࡢ㝈⏺ ௨ୗࡍࡿࡇࢆ┠ⓗࡋ࡚࠸ࡿࠋࡇࡢࢱࢫࢡࢢࣝ ⿵ṇ࡞⒪⨨ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢᑐࡍࡿ࢞ ࣮ࣉࡣ gold standard ࢹ࣮ࢱࢆ࠼ࡿࡶࡢ࡛ࡣ࡞࠸ࡋࠊ ࢻ່ࣛࣥ࿌ࢆᥦ౪ࡍࡿࠋࡓࡔࡋࠊSRS 17ࠊ ≉ᐃࡢ TPS ᑐࡍࡿࢹ࣮ࢱ ᐃࢆྲྀࡾᢅ࠺ࡶࡢ࡛ Gamma KnifeࠊCyberKnifeࠊTotal Skin Electron Therapy ࡶ࡞࠸ࡀࠊ࡛ࡁࡿ㝈ࡾ࠶ࡽࡺࡿ ᐃࢆ࢝ࣂ࣮࡛ࡁࡿ 㸦TSET㸧23ࠊTotal Body Irradiation㸦TBI㸧24 ࡞ࡢ ࡼ࠺ࡋ࡚࠸ࡿࠋࡇࡢࢱࢫࢡࢢ࣮ࣝࣉࡢㄢ㢟ࡣࠊࣅ ≉Ṧ⒪ࡣ⠊ᅖእࡋ࡚࠸ࡿࠋࡇࡢࢱࢫࢡࢢ࣮ࣝࣉ ࣮࣒≉᭷ࡢᛶ㉁ࢆ≉ᚩ࡙ࡅグ㘓ࡍࡿࠊ ͆ࣅ࣮࣒ࢹ࣮ ࡣ㏻ᖖࡢࣜࢽࢵࢡ࠾ࡅࡿගᏊ⥺㟁Ꮚ⥺ࡢࡳ ࢱࢥ࣑ࢵࢩࣙࢽࣥࢢ͇ᑐࡍࡿᢏ⾡ࡸ᳨ฟჾࡢ㑅ᢥ ࢆᑐ㇟ࡋ࡚࠸ࡿࠋ ᑐࡋ࡚ᐃࡵࡽࢀ࡚࠸ࡿࠋ୍⯡ࠊࡑࢀࡣࡇࡢᚋࡢ సᴗ࡛࠶ࡿィ⟬ࣝࢦࣜࢬ࣒ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ I.B.4. ࢥ࣑ࢵࢩࣙࢽࣥࢢࡢసᴗ㔞 ࡛⏝ࡉࢀࡿࠋᆒ㉁⿵ṇ㛵ࡋ࡚ࡶࠊ⌧௦ࡢࣝ ᚲせࡉࢀࡿࢥ࣑ࢵࢩࣙࢽࣥࢢࢹ࣮ࢱࡢ㔞ࡣࣘ ࢦࣜࢬ࣒㸦ࣔࣥࢸ࢝ࣝࣟࠊconvolution/superposition㸧 ࣮ࢨ࣮ࡢ⮫ᗋⓗᚲせᛶࠊTPSࠊMU ィ⟬ࣉࣟࢢ࣒ࣛࠊ ࠾ࡅࡿ㔜せ࡞ഃ㠃࡛࠶ࡿࡀࠊࡇࡢ✀ࡢࢥ࣑ࢵࢩࣙ タෆ࡛ᚲせ࡞ࢹ࣮ࢱࢸ࣮ࣈࣝ࡞ࡼࡗ࡚ኚ ࢽࣥࢢࡣᐇࡍࡿࡢࡀࡼࡾᅔ㞴࡛࠶ࡾࠊTPS ౫Ꮡ ࡍࡿࠋTable I㸦a㸧࠾ࡼࡧ㸦b㸧ࡣගᏊ⥺㟁Ꮚ⥺ ࡍࡿࠋࡑࢀࡺ࠼ࡇࡢࢱࢫࢡࢢ࣮ࣝࣉ࡛ࡣᆒ㉁⿵ṇ ᑐࡍࡿ ᐃ㡯┠ࡢ୍࡛࠶ࡿࠋ↷ᑕ㔝 1 × 1 cm2 ࡽ 㛵ࡋ࡚ࡣ⠊ᅖእࡋࠊᚋࡢࢱࢫࢡࢢ࣮ࣝࣉ᳨࡛ 40 × 40 cm2ࠊ῝ࡉ 0 ࡽ 40 cm ࡞ᖜᗈ࠸ࢹ࣮ࢱࢆࠊ ウࡍࡿࡇࡍࡿࠋࡲࡓࠊูࡢࢱࢫࢡࢢ࣮ࣝࣉ㸦SRS 1-3 ✀㢮ࡢගᏊ⥺࢚ࢿࣝࢠ࣮࠾ࡼࡧ 0-8 ✀㢮ࡢ㟁Ꮚ 17 ⥺࢚ࢿࣝࢠ࣮ᑐࡋ࡚⾜࠺ᚲせࡀ࠶ࡾࠊࣜࢽࢵࢡ ࠊIMRT 18,19 20 ࠊ࣊ࢵࢻᩓ㸦TG-74 㸧ࠊࣇ࣒ࣝࢻ 21 22 ࠊ㟁Ꮚ⥺㸦TG-70 㸧࡞㸧 ࢩ࣓ࢺࣜ㸦TG-69 㸧 ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ㔞ࡣⳘ࡛࠶ࡿࠋྲྀᚓࡍࡁࢹ 㔜」ࡍࡿෆᐜࡶ࠶ࡿࠋᚲせᛂࡌ࡚ࠊࡇࡢࢱࢫࢡࢢ ࣮ࢱ㔞ࠊ≀⌮ࢫࢱࢵࣇࡢປാ㔞ࢆ⪃៖ࡋ࡚ࣅ࣮࣒ 21 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 ࢹ࣮ࢱ ᐃࡢ㛫ࢆỴᐃࡍࡿࡇࡣ㔜せ࡛࠶ࡾࠊࢹ ࣑ࢵࢩࣙࢽࣥࢢࡢ୍㒊ࢆ࢝ࢵࢺࡋ࡚㛫ࢆ๐ῶࡍ ࣮ࢱࡢྲྀᚓ㛫ࡢぢ✚ࡶࡾࡣ⒪⨨ࡢཷࡅධࢀ ࡿࡇࡣྍ⬟࡛࠶ࡿࠋ 㸦ࢫ࢟ࣕࢽࣥࢢ࠾ࡅࡿ㸧࣏ ࡼࡾࡶ๓⾜࠺ᚲせࡀ࠶ࡿࠋ୍ࡋ࡚ࠊ2 ࡘࡢග ࣥࢺ ᐃࡢ㞟㛫ࡢ▷⦰ࠊࢫ࢟ࣕࢽࣥࢢ㏿ᗘࡢ Ꮚ⥺࢚ࢿࣝࢠ࣮ᑐࡋ࡚ࠊ6 ࡘࡢࢫ࢟ࣕࢽࣥࢢࢹ࣮ ቑຍࠊ ᐃ㛫ࡢ㐜ᘏ㛫ࡢ๐ῶ࡞ࡼࡗ࡚ࡶయ ࢱࢭࢵࢺ㸦1 ࡘࡢ PDDࠊ5 ࡘࡢ῝ࡉ࡛ࡢࣉࣟࣇ ࡢ㛫ࢆῶࡽࡍࡇࡀ࡛ࡁࡿࠋࡋࡋ࡞ࡀࡽࠊ㛫 ࣝ㸧ࢆ 15 ࡢ↷ᑕ㔝ࢧࢬ࡛ࠊ5 ࡘࡢ᮲௳㸦࣮࢜ࣉࣥࠊ ๐ῶࡢࡓࡵࡢࢫ࢟ࣕࢽࣥࢢࣃ࣓࣮ࣛࢱࡢኚ᭦ࡣࣅ 4 ࡘࡢ≀⌮࢙࢘ࢵࢪ㸧ᑐࡋ࡚ྲྀᚓࡍࡿሙྜࠊᘧ(1) ࣮࣒ࢹ࣮ࢱࡢ㉁ᙳ㡪ࢆ࠼ࡿࠋᐇ㝿ࡇࢀࡽࢆ⾜ ࡢࡼ࠺㛫ࡀぢ✚ࡶࡽࢀࡿࠋ ࠺๓ࠊ↷ᑕ㔝ࡢࣉࣟࣇࣝ ᐃ࡞ࡢࢸࢫࢺ ࢫ࢟ࣕࣥࢆ⾜࠸ࠊࣅ࣮࣒ࢹ࣮ࢱㄗᕪࢆ⏕ࡌ࡞࠸ࡇ Time 㹼 [ (PDD + 5 Profiles) / beam energy] × ࢆ☜ㄆࡍࡿᚲせࡀ࠶ࡿࠋ (open + 4 wedges) × (60 points/scan) II. ࣇࣥࢺ࣒ࡢᮦ㉁⏝ἲࠊ᳨ฟჾ × [1 s/pts + 1 s (movement and delay) ] 5 II.A. ࣇࣥࢺ࣒ᮦ㉁ × 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 ᶵჾࡢࢭࢵࢺࢵࣉࠊ⨨ࣃ࣓࣮ࣛࢱࡢኚ᭦ࠊ ࣀࣥࢫ࢟ࣕࣥࢹ࣮ࢱ㸦࣏ࣥࢺࢹ࣮ࢱ㸧ࡢ 2 ㏻ࡾࡀ ⨨ࡢࢺࣛࣈࣝ࡞ࢆ⪃៖ࡍࡿࠊගᏊ⥺ࢫ࢟ࣕࢽࣥ Ꮡᅾࡍࡿࠋ࣏ࣥࢺࢹ࣮ࢱࡣᅛయࣇࣥࢺ࣒㸦ᚋ㏙㸧 ࢢࢹ࣮ࢱࡢྲྀᚓᚲせ࡞㛫ࡣ୍⯡ⓗ 1.5 㐌㛫࡛ ࡶࡋࡃࡣỈࣇࣥࢺ࣒ࢆ⏝࠸࡚ ᐃࡍࡿࡇࡀ࡛ ࠶ࡿࠋࡶ࠺ 1 㐌㛫ࡣ࣏ࣥࢺࢹ࣮ࢱࡢྲྀᚓ㈝ࡸࡋࠊ ࡁࡿࠋࢫ࢟ࣕࣥࢹ࣮ࢱࡢྲྀᚓࡣࢫ࢟ࣕࢽࣥࢢỈࣇ 1-2 㐌㛫ࢆ㟁Ꮚ⥺ࠊ ṧࡾ 1 㐌㛫ࡣ᳨ドᚲせ࡞ࡿࠋ ࣥࢺ࣒ࢆ⏝࠸࡚⾜ࢃࢀࠊ୍⯡ 40 cm ῝ࡲ࡛ࡢ୰ᚰ ࡲࡓࠊ୍⯡ⓗゎᯒ࠾ࡼࡧ࣏࣮ࣞࢺࡢసᡂࡣ 1-2 ㍈ PDD ࣉࣟࣇࣝࢆ ᐃࡍࡿࡇࡀྍ⬟࡛࠶ 㐌㛫ࢆせࡍࡿࠋࡇࢀࡽࢆྜィࡍࡿࢥ࣑ࢵࢩࣙࢽࣥ ࡿࠋࡇࢀࡽࡣ 2 ḟඖ࠶ࡿ࠸ࡣ 3 ḟඖỈࣇࣥࢺ࣒ ࢢࡾᙜ࡚ࡽࢀࡿ㛫ࡣ 4-6 㐌㛫࡞ࡿࠋࡋࡋ ࡞࠸ࡃࡘࡢࣂ࢚࣮ࣜࢩࣙࣥࡀ࠶ࡿࠋỈ㸦ࢫ࢟ࣕ ࡞ࡀࡽࠊࣀࣥࢫ࢟ࣕࣥࢹ࣮ࢱࡢྲྀᚓࠊQA ࡢࡓࡵࡢ ࢽࣥࢢ㸧ࢱࣥࢡࡣᑡ࡞ࡃࡶ 40 × 40 cm2 ࡢ↷ᑕ㔝ࢆ ᇶ‽ࢹ࣮ࢱࡢྲྀᚓࠊ࣋ࣥࢳ࣐࣮ࢡヨ㦂ࠊTPS ࢹ࣮ࢱ 40 cm ῝࡛ ᐃ࡛ࡁࡿࡶࡢ࡛࡞ࡅࢀࡤࠊᩓ᮲௳ࡀ ࡢ᳨ド࡞㏣ຍࡢ㛫ࢆぢ✚ࡶࡿᚲせࡀ࠶ࡿࠋࢥ ༑ศ࡛࠶ࡾ⏝ࡍࡁ࡛࡞࠸ࠋࡲࡓࠊගᏊ⥺ᑐ ࣑ࢵࢩࣙࢽࣥࢢチࡉࢀࡓ㛫ෆ࡛ࡍ࡚ࡢࢹ࣮ ࡍࡿࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣ cross-plane in-plane ࢱࢆྲྀᚓࡍࡿᚲせࡀ࠶ࡿࡓࡵࠊࡾࢃࡅ᭱ప㝈ࡢ≀ 㸦x ᪉ྥ y ᪉ྥ㸧ࡢ୧᪉ࡢࢫ࢟ࣕࣥࡀ࡛ࡁࡿᚲせ ⌮ࢧ࣏࣮ࢺࡋᚓࡽࢀ࡞࠸タ࡛ࡣࠊ≀⌮ࢫࢱࢵࣇ ࡀ࠶ࡿࠋ୧᪉ྥࢫ࢟ࣕࣥࡀྍ⬟࡛࠶ࡿࡇ࡛ࠊ⡆ ࡣᅔ㞴ࢆᙉ࠸ࡽࢀࡿࡔࢁ࠺ࠋᑡᩘࡢ≀⌮ኈࡀ㎿㏿ ౽ࢹ࣮ࢱྲྀᚓ࡛ࡁࠊࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢᅇ㌿ ࢹ࣮ࢱࢆྲྀᚓࡋࡼ࠺ࡍࢀࡤࠊࢹ࣮ࢱࡢ㉁ᙳ㡪ࡍ ࡼࡿ࣓ࣛࣥࢺ࢚࣮ࣛࢆ㑊ࡅࡿࡇࡀ࡛ࡁࡿࠋ ࡿྍ⬟ᛶࡀ࠶ࡿࠋ TPS ࡼࡗ࡚ࡣ jaw ࡼࡿ↷ᑕ㔝ࡢࢹ࣮ࢱࡔࡅࡀᚲ ࡶࡋྠࢱࣉ࡛ࣅ࣮࣒≉ᛶࢆྜࢃࡏ㎸ࢇࡔ」ᩘ ࡢ⨨ࡀ࠶ࢀࡤࠊ Marshall ࡽ 25 ࡀሗ࿌ࡋ࡚࠸ࡿࡼ ࠺ప࢚ࢿࣝࢠ࣮ࣅ࣮࣒㛵ࡋ࡚ࡣࠊࣅ࣮࣒ࢹ࣮ࢱ ࡣࡼࡃ୍⮴ࡍࡿࡣࡎ࡛࠶ࡿࠋࡋࡋ࡞ࡀࡽࠊ⌧௦ࡢ せ࡛ࠊMLC ࡣ TPS ࡢෆ㒊࡛ࣔࢹࣜࣥࢢࡉࢀ࡚࠸ࡿ ࡇࡀ࠶ࡿࠋࡋࡋ࡞ࡀࡽ MLC ↷ᑕ㔝ࡢࢹ࣮ࢱࡣ ࣔࢹࣝࡢ᳨ドࡢࡓࡵࡸࡣࡾᚲせ࡛࠶ࡿࠋ ㈓ỈࢱࣥࢡỈࡀ㈓ࡵ࡚࠶ࡾࠊࢫ࢟ࣕࢽࣥࢢࢱࣥ ⨨࠾ࡅࡿᐃ㔞ⓗ࡞ホ౯࡛ࡣ 1 ḟඖࡢ࣐࢞ࣥゎᯒ ࢡỈࢆ࣏ࣥࣉ࡛ࡃࡳୖࡆࡿࡼ࠺࡞ࢩࢫࢸ࣒ࡢሙ ࡛ࠊ2 ྎࡢྠ✀ࡢ⨨࠾࠸࡚ࠊྠ᮲௳࡛ྲྀᚓࡋࡓ ྜࠊ㥑ື⣔⸴㢮ࡀⓎ⏕ࡋ࡞࠸ࡼ࠺ẅ⳦ࢆᢞࡋ 」ᩘࡢࣉࣟࣇࣝࡢ࠺ࡕࠊ30%ࡀṇ☜ࡣ୍⮴ࡋ ࡓ␃Ỉࢆ࠺ᚲせࡀ࠶ࡿࠋࡶࡋ㈓Ỉࢱࣥࢡࡀ࠼ 26 ࡞࠸ࡇࡀ♧ࡉࢀ࡚࠸ࡿ ࠋ㐺ษ࡞ゎᯒࡼࡿࢧࣥ ࡞࠸ሙྜࠊỈ ࢆࣔࢽࢱࣜࣥࢢࡋ࡚ࠊࢹ࣮ࢱ ᐃ๓ ࣉࣝࢹ࣮ࢱࡢẚ㍑⤖ᯝࡀタෆ࡛ࡢチᐜ್㸦ᇶᮏⓗ ࡣᐊ ྠ➼ࡍࡿᚲせࡀ࠶ࡿࠋ࠸ࡃࡘࡢ᳨ฟ ࡣӌs1%㸧ࢆ‶ࡓࡏࡤࠊྠ୍⨨ᑐࡋ࡚ࡢࡳࢥ ჾ࡛ࡣ ᗘᑐࡍࡿ⿵ṇࡀ༑ศ⪃៖ࡉࢀ࡚࠸࡞࠸ 22 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) ࡓࡵࠊ࡛ࡁࡿ㝈ࡾᐊ ㏆ࡅࡿࡇࢆ᥎ዡࡍࡿ 27 ࠋ ㌿ࡉࡏ࡚ࢹ࣮ࢱࢆྲྀᚓࡍࡿᚲせࡀ࠶ࡿࠋ୍⯡ⓗࢥ ࡑࡢࡓࡵࠊᐊ ᖹ⾮≧ែ࡞ࡿࡼ࠺Ỉࢆࡋࡤࡽࡃ ࣓࣮ࣜࢱࢆᅇ㌿ࡉࡏ࡚ࡶࣇࣛࢵࢺࢽࣥࢢࣇࣝࢱ ᐊෆ⨨࠸࡚࠾ࡃᚲせࡀ࠶ࡿࠋ ࡢᙧ≧ሗࡣᚓࡽࢀ࡞࠸ࡓࡵࠊࢥ࣓࣮ࣜࢱᅇ㌿ࡼ ࣅ࣮࣒ࢫ࢟ࣕࢽࣥࢢࡣ୍⯡ⓗᩘ᪥㛫௨ୖ ࡗ࡚ࡇࢀࡽࡢࢹ࣮ࢱࢆྲྀᚓࡋ࡚ࡣ࡞ࡽ࡞࠸ࠋ ࡿࡓࡵࠊ⸴㢮ࡀⓎ⏕ࡋ࡚ࣅࣝࢻࢵࣉࢆᙧᡂࡍࡿࡇ ᑐゅ⥺᪉ྥࡢࣉࣟࣇ࡛ࣝࡣ 75 × 75 cm2 ࡼࡾ ࡀ࠶ࡿࠋࡇࢀࡣࢱࣥࢡෆࡢỈࡀ㏱᫂ࡽࡗࡓ≧ ࡁ࡞ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡀዲࡲࡋ࠸ࡀࠊ⌧ᐇࡣ ែኚࡍࡿࡇࡀ♧၀ࡢ 1 ࡘ࡞ࡿࠋࡈࡃᑡ㔞ࡢ SSD = 100 cmࠊ30 cm ῝௨ୖࠊ↷ᑕ㔝 40 × 40 cm2 Ὑࡸሷ⣲ࢆຍ࠼ࡿࡇ࡛⸴㢮ࢆຠᯝⓗ㝖ཤ࡛ ࠸࠺᮲௳ࡢᑐゅ⥺᪉ྥࣉࣟࣇࣝ+5 cm ࡢ࣮࢜ࣂ ࡁࡿࠋࡇࢀࡽࡣ ᐃࢆ㛤ጞࡍࡿ๓ࠊỈࡀ⃮ࡾࡔࡋ ࣮ࢫ࢟ࣕࣥࢆ ᐃ࡛ࡁࡿၟ⏝ࡢࢫ࢟ࣕࢽࣥࢢࢩࢫ ࡓࡽ༶ᗙ⾜࠺ᚲせࡀ࠶ࡿࠋὙࢆຍ࠼ࡿࡇࡢࡶ ࢸ࣒ࡣࢇᏑᅾࡋ࡞࠸ࠋጇ༠Ⅼࡋ࡚ࠊ↷ᑕ㔝 ࠺୍ࡘࡢⅬࡣ⾲㠃ᙇຊࢆῶᑡࡉࡏࠊࢭࢵࢺࢵࣉ ࡢ∦ഃ༙ศࡢࡳࢆࢫ࢟ࣕࣥࡍࡿ᪉ἲ㸦ࣁ࣮ࣇࢫ࢟ࣕ ࡢ᳨ฟჾ⨨ࢆどぬⓗࢃࡾࡸࡍࡃ࡛ࡁࡿⅬ ࣥ㸧ࡀ࠶ࡿࡀࠊࣁ࣮ࣇࢫ࡛࢟ࣕࣥࡣ᭱↷ᑕ㔝 ᐃ ࡛࠶ࡿࠋከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢ〇㐀ᴗ⪅ࡣ ᑐࡋ࡚୰ᚰ㍈࢜ࣇࢭࢵࢺࢆຍ࠼࡚ ᐃࡋ࡞ࡅ ࣁ࣮ࢻ࢙࢘ࢆಖㆤࡍࡿࡓࡵࡢ⸆ရࢆᥦ౪ࡋ࡚࠸ ࢀࡤ࡞ࡽ࡞࠸ࠋࣁ࣮ࣇࢫ࢟ࣕࣥࢆ⾜࠺๓ࠊ࣮࢜ࣉ ࡿࠋ ࣥ↷ᑕ㔝ࡢ㠀ᑐ⛠ᛶࡀ 0.5%௨ୗ࡛࠶ࡿࡇࢆ☜ㄆ ຍ࠼࡚ࠊࢫ࢟ࣕࢽࣥࢢࢹ࣮ࢱྲྀᚓ୰ࡢỈࡢⓎࡶ ࡍࡿࡇࡼࡾࠊ࣑࣮ࣛࢥࣆ࣮ࡋࡓࢹ࣮ࢱࡀయࢆ ୍⯡ⓗ࡞ၥ㢟࡛࠶ࡿࠋࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢࡁࡉ ⾲ࡋ࡚࠸ࡿࡳ࡞ࡍࡇࡀ࡛ࡁࡿࠋࡲࡓࠊࡼࡾ῝࠸ ࡶࡼࡿࡀࠊỈࡢⓎࡣ↓ど࡛ࡁ࡞࠸᳨ฟ 㡿ᇦ࡛ࡣᶓ᪉ྥࡢᩓࢆ༑ศ⪃៖ࡍࡿࡓࡵࠊࣁ࣮ ჾࡢ῝ࡉࢆኚ࠼࡚ࡋࡲ࠺ࡇࡀ࠶ࡿࡢ࡛ࠊ≉㛗ᮇ ࣇࢫ࢟ࣕࣥࡣ୰ᚰ㍈ࡼࡾ᭱ప࡛ࡶ+5 cm ᑐഃ 㛫ཬࡪࢫ࢟ࣕࢽࣥࢢ࡛ࡣࠊᐃᮇⓗỈ㠃ࢆ☜ㄆࡍ ࡲ࡛ࢫ࢟ࣕࣥࡍࡿࡇࡀ᥎ዡࡉࢀࡿࠋࣁ࣮ࣇࢫ࢟ࣕ ࡿࡇࢆ᥎ዡࡍࡿࠋࣅ࣮࣒ࢫ࢟ࣕࢽࣥࢢࢆ⤊ࡋࡓ ࣥࡣࢭࢵࢸࣥࢢࡼࡾ㛗࠸㛫ࢆせࡍࡿࠋTPS ࡢ 㝿ࡣࠊࢫ࢟ࣕࢽࣥࢢࢱࣥࢡෆࡢỈࢆฟࡋ せ௳ࡼࡿࡀࠊࢫ࢟ࣕࣥࡢ࡞ࢹ࣮ࢱࢭࢵࢺࢆస ⇱ࡉࡏࡿᚲせࡀ࠶ࡿࠋࡣࢫ࢟ࣕࢽࣥࢢࡢࣁ࣮ࢻ ᡂࡍࡿࡓࡵࢹ࣮ࢱ᧯సࡀᚲせ࡞ࡿሙྜࡶ࠶ࡿࠋ ࢙࢘ᑐࡋᑡ㔞ࡢ࢜ࣝࢆὀࡍᚲせࡀ࠶ࡿሙྜ 㛫๐ῶࢆ⾜࠺ࡋ࡚ࡶࠊධຊࢹ࣮ࢱࡋ࡚ࢩࢫࢸ ࡶ࠶ࡿࠋ࣑ࢿࣛࣝỿ╔ࡸ⸴㢮ࡢⓎ⏕ࡣࣁ࣮ࢻ࢙࢘ ࣒㸦TPS㸧㐺ྜࡋࡓࢹ࣮ࢱ࡛࠶ࡿ☜ㄆࡍࡿᚲせ ࡢࢲ࣓࣮ࢪ࡞ࡿࡓࡵࠊࢫ࢟ࣕࢽࣥࢢࢱࣥࢡෆỈ ࡀ࠶ࡿࠋ ࢆṧࡉ࡞࠸ࡇࢆ᥎ዡࡍࡿࠋ II.C. ᅛయࣇࣥࢺ࣒ II.B. ࣇࣥࢺ࣒ࡢᑍἲ ࣏ࣥࢺ⥺㔞࠾ࡼࡧࣀࣥࢫ࢟ࣕࣥࢹ࣮ࢱ㸦ฟຊಀ ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢࢧࢬࡣ᭱↷ᑕ㔝ࡢࣉ ᩘࠊ⾲㠃⥺㔞ࠊ₃࠼࠸/㏱㐣 ᐃࠊ࢙࢘ࢵࢪ࠾ࡼࡧࢺ ࣟࣇࣝ ᐃᑐࡋ࡚༑ศࡁ࠸ᚲせࡀ࠶ࡿ㸦ග ࣞಀᩘ࡞㸧ࡢ ᐃࡣỈࣇࣥࢺ࣒࡛ྍ⬟࡛ࠊከ 2 Ꮚ⥺࡛ࡣ 40 × 40 cm ຍ࠼࡚༑ศ࡞ഃ᪉ࣅࣝࢻ ࡃࡢሙྜࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࢆ⏝࠸࡚⾜ࢃࢀࡿ ࢵࣉ㸦5 cm㸧࣮࢜ࣂ࣮ࢫ࢟ࣕࣥ㊥㞳ࢆྵࡵࡓࢧ ࡀࠊỈࢆᶍᨃࡋࡓᅛయࣇࣥࢺ࣒ࡶ⡆౽ᛶࡽ⏝࠸ ࢬ㸧 ࠋTPS ࡼࡗ࡚ࡣࠊࣔࢹࣜࣥࢢࡢࡓࡵ᭱↷ ࡿࡇࡀ࡛ࡁࡿࠋࢡࣜࣝࡸ࣏ࣜࢫࢳࣞࣥ࡞Ỉ௨ ᑕ㔝ࡘ 40 cm ῝࡛ᶓ᪉ྥࡼࡾࡁ࡞ࢫ࢟ࣕࣥࡸࠊ እࡢࣉࣛࢫࢳࢵࢡ⣲ᮦࡣ Table II ࡸࡢᩥ⊩ ᑐゅ⥺᪉ྥࡢࢫ࢟ࣕࣥࢆᚲせࡍࡿሙྜࡶ࠶ࡿࠋ㐺 ♧ࡍࡼ࠺㟁Ꮚ⃰ᗘࠊ㜼Ṇ⬟㸦S㸧 ࠊ㉁㔞࢚ࢿࣝࢠ࣮ ษ࡞ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࢧࢬࢆỴᐃࡍࡿࡓࡵࠊ࢜ ྾ಀᩘ㸦Pen/U㸧࡞ࡀ␗࡞ࡾ⿵ṇࡀᚲせ࡛࠶ࡿࡓ ࣮ࣂ࣮ࢫ࢟ࣕࣥ㡿ᇦ 40 cm ῝࡛ࡢࣅ࣮࣒ࡢᗈࡀࡾ ࡵࠊὀពࡋ࡚⏝ࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋTello 29 ࡽࡣࠊ ࢆ⪃៖ࡍࡿᚲせࡀ࠶ࡿࠋ᭱↷ᑕ㔝ࡢ 1.6 ಸࡀᏳ Ỉᑐࡋ࡚ᅛయࣇࣥࢺ࣒ෆ࡛ࡢගᏊࡸ㟁Ꮚࡢᣲ 2 28, 29 ࡛࠶ࡾࠊ༢⣧ィ⟬࡛ࡣ 75 × 75 cm ࡀ⌮ⓗ࡞ࢧࢬ ືࡀࣅ࣮࣒ࡢ࢚ࢿࣝࢠ࣮ࡼࡗ࡚␗࡞ࡿࡇࢆ♧ ࡛࠶ࡿࠋࡶࡋࢫ࢟ࣕࢽࣥࢢࢯࣇࢺ࢙࢘ࡀᑐゅ⥺᪉ ࡋࠊᅛయࣇࣥࢺ࣒ࡢᨺᑕ⥺Ꮫⓗ≉ᛶࡀṇ☜ࡣỈ ྥࡢࢫ࢟ࣕࣥᑐᛂࡋ࡚࠸࡞ࡅࢀࡤࠊࢸ࣮ࣈࣝࢆᅇ ␗࡞ࡿࡇࡀᣦࡉࢀ࡚࠸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 Pen / 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, CIRS Lavender 1012 1.032 1.031 1.030 1.030 White 1045 1.035 1.036 1.049 1.056 White water-RW-3, NA ᅛయࣇࣥࢺ࣒ࡣ᳨ฟჾᙧ≧ྜࢃࡏࡓ✸Ꮝຍ ᕤࡀᚲせ࡛ࠊ᳨ฟჾࢆᤄධࡋࡓ≧ែ࡛ kV ࡢ X ⥺࡛ ࣉࢆ㑅ࡪࡇࡀ㔜せ࡛࠶ࡾࠊࡉࡶ࡞ࡅࢀࡤㄗࡗࡓࢹ ࣮ࢱࢆྲྀᚓࡍࡿྍ⬟ᛶࡀ࠶ࡿࠋSec. IV. C.࡛ヲ㏙ࡍࡿࠋ ᙳࡋࠊᙧ≧ࡢ୍⮴ࢆ☜ㄆࡍࡁ࡛࠶ࡿࠋ᳨ฟჾࡈ ࡢᙧ≧ྜࢃࡏ࡚ຍᕤࡉࢀࡓࣇࣥࢺ࣒ࢆ⏝ II.E. ᳨ฟჾ ࡍࡿᚲせࡀ࠶ࡿࠋ᳨ฟჾࢆᅛయࣇࣥࢺ࣒ᤄධࡋ II.E.1. ྛ᳨ฟჾࡢ᭷⏝ᛶ ᵝࠎ࡞〇㐀ᴗ⪅ࡀᖜᗈ࠸✀㢮ࡢ᳨ฟჾࢆసࡗ࡚ ࡓࡢࡕࠊ ᗘࡀᖹ⾮࡞ࡿࡲ࡛⨨࠸࡚࠾ࡃᚲせࡀ࠶ 30 ࡿ ࠋࣇࣥࢺ࣒ࡢရ㉁ࡣ CT ࢆീࡋࠊ࣮ࢳࣇ ࠾ࡾࠊ㟁㞳⟽ࠊ༙ᑟయࠊࢲࣔࣥࢻ᳨ฟჾ࡞ࡀ ࢡࢺࡸ CT ್ࢆࡋ࡚㟁Ꮚ⃰ᗘࡢᆒ㉁࡞㒊ศࡀ Ꮡᅾࡍࡿࠋࡇࢀࡽࡢ᳨ฟჾࡣࢧࢬࡼࡗ࡚ᶆ‽ᆺࠊ ࡞࠸ࢆ☜ㄆࡍࡁ࡛࠶ࡿࠋ ࡲࡓࠊࣇࣥࢺ࣒ࡣ ࣑ࢽᆺࠊ࣐ࢡࣟᆺศ㢮࡛ࡁࡿࠋ᫂☜࡞ᐃ⩏ࡣ࡞ MV ࡢ࢚ࢿࣝࢠ࣮࠾࠸࡚Ỉྠ➼ࡢᣲືࢆ♧ࡍࡼ ࠸ࡀࠊ㟁㞳⟽ࡣ᭷ឤయ✚ࡼࡗ࡚௨ୗࡢࡼ࠺ศࡅ ࠺సࡽࢀ࡚࠸ࡿࡓࡵࠊkV ࡢ CT ್ࡀỈ␗࡞ࡗ ࡽࢀࡿࠋ ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿⅬὀពࡍࡿࠋ x 㞳⟽ࡣ 0.6 cm3 ࡢ᭷ឤయ✚ࢆ᭷ࡋ࡚࠸ࡿࠋ II.D. ࣅࣝࢻࢵࣉ࢟ࣕࢵࣉ ✵୰ฟຊಀᩘࠊࡶࡋࡃࡣ࣊ࢵࢻᩓಀᩘ㸦Sc㸧ࡢ x ࣇࣥࢺ࣒ࡀ⏝࠸ࡽࢀ࡚ࡁࡓࠋၟ⏝࡛⏝ྍ⬟࡞ࣅ ࣑ࢽᆺ㸦~10-2 cm3㸧– ࣑ࢽᆺࡢ㟁㞳⟽ࡣᖹᆒ ࡋ࡚ 0.05 cm3 ࡢ᭷ឤయ✚ࢆ᭷ࡋ࡚࠸ࡿࠋ ᐃ࡛ࡣࠊᚑ᮶ࣅࣝࢻࢵࣉ࢟ࣕࢵࣉࡶࡋࡃࡣ࣑ࢽ x ࣐ࢡࣟᆺ㸦~10-3 cm3㸧– ࣐ࢡࣟᆺࡢ㟁㞳⟽ ࡣᖹᆒࡋ࡚ 0.007 cm3 ࡢ᭷ឤయ✚ࢆ᭷ࡋ࡚࠾ ࣝࢻࢵࣉ࢟ࣕࢵࣉ㸦Radiation Products Design, Albertville, MN 230㸧ࡣ࢚ࢿࣝࢠ࣮ࡼࡗ࡚ࡣΰධ㟁 Ꮚࢆ㝖ཤࡍࡿࡢ༑ศ࡛࡞࠸ሙྜࡀ࠶ࡿࠋTG-74 ᶆ‽ᆺ㸦~10-1 cm3㸧 – ᶆ‽ⓗ࡞ࣇ࣮࣐ᙧ㟁 20 ࡾࠊᐃ↷ᑕࡸ Gamma KnifeࠊCyberKnifeࠊIMRT ࡞ᑠ↷ᑕ㔝ࡢ ᐃ㐺ࡋ࡚࠸ࡿࠋ ࡛ࡣḟ㟁Ꮚᖹ⾮ࢆ㐩ᡂࡋࠊΰධ㟁Ꮚࢆ㝖ཤ࡛ࡁࡿ ࣑ࢽࣇࣥࢺ࣒ࡢ⏝ࡀ᥎ዡࡉࢀ࡚࠸ࡿࠋ4 × 4 cm2 II.E.2. ᳨ฟჾࡢ✀㢮 ௨ୗࡢᑠ↷ᑕ㔝࡛ࡣỈ➼౯ࡢ࣑ࢽࣇࣥࢺ࣒ࢆ⏝ 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ࡢᮦ ᛶࡸ⌧ᛶࡀⰋዲ࡛࠶ࡿࡇࡽࠊᨺᑕ⥺ࡢⓎぢ ㉁ࡢ࣑ࢽࣇࣥࢺ࣒ࢆ⏝࠸࡚ࠊࡍ࡚ࡢ Sc ࢆྠ୍ࡢ ࡼࡾ⌧ᅾࡲ࡛ᖜᗈࡃࢃࢀ࡚࠸ࡿࠋ㟁㞳⟽ࡣᅜᐙᶆ ㊥㞳࡛⾜࠺ࡇࡀࡼࡾࡼ࠸᪉ἲࡋ࡚᥎ዡࡉࢀ࡚ ‽ᑐࡋ࡚ᰯṇࡍࡿࡇࡀྍ⬟࡛ࠊ⥺㔞ࢆ┤᥋ ᐃ ࠸ࡿࠋ㔠ᒓࡢ࣑ࢽࣇࣥࢺ࣒ࢆࢯࢭࣥࢱ࡛⏝ ࡍࡿࡇࡀ࡛ࡁࡿࠋ㟁㞳⟽ࡣẚ㍑ⓗᏳ౯࡛ࠊᐜ᫆ ࡛ࡁࡿࡼ࠺ࠊTG-74 ࡛㐺ษ࡞⿵ṇಀᩘࡀ♧ࡉࢀ࡚࠸ ධᡭ࡛ࡁࠊᵝࠎ࡞ᙧ≧㸦⟄ᙧࠊ⌫ᙧࠊᖹ⾜ᖹᯈᙧ ࡿ 31 ࠋ࣑ࢽࣇࣥࢺ࣒ࡢᆺⓗ࡞㛗㍈᪉ྥࡢ㛗ࡉࡣ 2 ࡞㸧ࢧࢬ㸦ᶆ‽ᆺࠊ࣑ࢽᆺࠊ࣐ࢡࣟᆺ㸧ࡢ 10 g/cm ࡔࡀࠊ⿵ṇಀᩘࢆ㐺⏝ࡍࢀࡤࡇࢀ௨እࡢ㛗 ࡶࡢࡀ〇㐀ࡉࢀ࡚࠸ࡿࠋHumphries Purdy 33 ࡣᵝࠎ ࡉࡶ⏝ྍ⬟࡛࠶ࡿ 32ࠋヲ⣽ࡣ TG-74 グ㍕ࡉࢀ࡚ ࡞ࣅ࣮࣒ࢹ࣮ࢱࢫ࢟ࣕࢽࣥࢢࡢࡓࡵࡢ㟁㞳⟽ࡑ ࠸ࡿࠋSc ࡢ ᐃࡣ༑ศ࡞ཌࡉࡢࣅࣝࢻࢵࣉ࢟ࣕࢵ ࡢ≉ᛶࢆࣜࢫࢺࡋࡓࠋࡋࡋࠊ⌧ᅾ࡛ࡣከࡃࡢ࣋ 24 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ษᰯṇࡉ ␗࡞ࡗࡓ㟁㞳⟽ࢆ㈍ࡋ࡚࠸ࡿࠋ᭱᪂ࡢ◊✲ᡂᯝࡸ ࢀ࡚࠸ࡿࡀࠊ⏝๓ࢳ࢙ࢵࢡࢆ⾜࠺ࡇࡣ⢭ᗘࢆ ᚲせᛶᇶ࡙࠸ࡓࠊ⏝┠ⓗࡈࡢᨺᑕ⥺᳨ฟჾࡢ ᢸಖࡍࡿୖ࡛ᚲせ࡛࠶ࡿࠋ㟁㞳⟽ࣞࢲ࣮࢜ ศ㢮ࡣᵝࠎ࡞〇㐀ᴗ⪅㸦PTW, BEST, IBA, Standard ࢻ࡛ࣞࢲࢼ࣑ࢵࢡ࢙࢘ࢵࢪᑐࡍࡿ ᐃ Imaging ࡞㸧ࡽᚓࡿࡇࡀ࡛ࡁࡿࠋ 㐪࠸ࡣ࡞࠸ࡇࡀሗ࿌ࡉࢀ࡚࠸ࡿࡢ࡛ࠊࡕࡽࡢࢩ ࢫࢸ࣒ࡶ⏝ྍ⬟࡛࠶ࡿ 44, 45ࠋ II.E.2.b. ࢲ࣮࢜ࢻ ༙ᑟయࢲ࣮࢜ࢻ᳨ฟჾࡣගᏊ⥺࣭㟁Ꮚ⥺࠸ࡎࢀ ࠾࠸࡚ࡶࣅ࣮࣒ࢹ࣮ࢱ ᐃᗈࡃ⏝࠸ࡽࢀ࡚࠸ II.E.2.d. ࢲࣔࣥࢻ᳨ฟჾ ࢲࣔࣥࢻ᳨ฟჾࡣ㟁Ꮚ-ṇᏍᑐࡢྍືᛶඃ ࡿࠋࢲ࣮࢜ࢻࡢ≉ᚩࡣ㏿࠸ᛂ⟅㛫㸦㟁㞳⟽࡛ࡣ ࢀࡓᅛయ᳨ฟჾ࡛ࠊ㟁㞳ᨺᑕ⥺ࡢ ᐃᑐࡋ࡚㨩ຊ msec ࡛࠶ࡿࡢᑐࡋPsec ࣮࢜ࢲ࣮㸧ඃࢀࡓ✵㛫 ⓗ࡞༙ᑟయ᳨ฟჾ࡛࠶ࡿࠋࢲࣔࣥࢻ᳨ฟჾࡢ ศゎ⬟ࢆᣢࡘࡇࠊ㟁ᅽࢆ༳ຍࡍࡿᚲせࡀ࡞࠸ࡇࠊ 㸦 ᐃ㸧⌮ㄽࡣࢲ࣮࢜ࢻ᳨ฟჾ㠀ᖖఝ࡚࠾ࡾࠊ 㧗ឤᗘ࡛࠶ࡿࡇࡀᣲࡆࡽࢀࡿࠋຍ࠼࡚ࠊࢲ࣮࢜ 㟁㞳ᨺᑕ⥺ࡀ྾ࡉࢀࡿ≀㉁ࡢఏᑟᛶࡀ୍ⓗ ࢻࡣ⮫ᗋ⏝ࡉࢀ࠺ࡿ 4-20 MeV ࡢ㟁Ꮚ⥺࠾࠸࡚ࠊ ኚࡍࡿ 46-50ࠋࢲࣔࣥࢻ᳨ฟჾࡢᛂ⟅ࡣ྾ ࢩࣜࢥࣥỈࡢ㛫࠾ࡅࡿ㉁㔞⾪✺㜼Ṇ⬟ẚࡀ࢚ ⥺㔞⋡ṇẚࡋࠊ᪉ྥ౫Ꮡᛶࡣ♧ࡉࡎࠊ⤌ᡂࡣே ࢿࣝࢠ࣮౫Ꮡࡋ࡞࠸ 34-36 ࠋࡑࢀࡺ࠼ࠊࢲ࣮࢜ࢻ య㏆࠸ࠋ᭷ឤయ✚ࡣ 1.0-6.0 mm3 㠀ᖖᑠࡉࡃࠊ ࡣ≉㟁Ꮚ⥺ࡢ ᐃ࠾࠸࡚᭷ຠ࡞᳨ฟჾ࡞ࡿࠋ ᑠ↷ᑕ㔝ࡢ࣏ࣥࢺ⥺㔞 ᐃࣉࣟࣇࣝ ᐃ ≉ᐃࡢࢲ࣮࢜ࢻࡣ≉ᐃࡢᨺᑕ⥺ࡢࡳ⏝ࡍ 㐺ࡋ࡚࠸ࡿࠋࢲࣔࣥࢻ᳨ฟჾࡣࢃࡎ⥺㔞 ࡁ࡛࠶ࡾࠊ㟁Ꮚ⥺⏝ࡣ㟁Ꮚ⥺ࡢࠊගᏊ⥺⏝ࡣගᏊ⥺ ⋡౫Ꮡࢆ♧ࡍࡀࠊỈ୰࠾ࡅࡿࢫ࢟ࣕࢽࣥࢢ ᐃ ࡢ ᐃࡢࡳ⏝࡛ࡁࡿࡇὀពࡍࡿᚲせࡀ࠶ ⏝ࡍࡿࡇࡀ࡛ࡁࡿࠋࢲࣔࣥࢻ᳨ฟჾࡣ〇㐀 ࡿࠋࡲࡓࠊࢲ࣮࢜ࢻ᳨ฟჾࡣ ᗘࠊ⥺㔞⋡㸦SSD ࡀ㞴ࡋ࠸ࡓࡵࠊࡢᅛయ᳨ฟჾẚ࡚㧗౯࡛࠶ ࡢ㐪࠸ࡸ࢙࢘ࢵࢪ⏝࡞㸧 ࠊ࢚ࢿࣝࢠ࣮ 34, 36-38 ࡿࠋ ᑐࡋ࡚౫Ꮡᛶࡀ࠶ࡾࠊࡲࡓゅᗘ౫Ꮡᛶࡀ࠶ࡿࡶࡢ ࡶᏑᅾࡍࡿࠋTG-62 39 ࡛᥎ዡࡉࢀ࡚࠸ࡿ⢭ᗘࢆ㐩ᡂ ࡍࡿࡓࡵࡣࠊࡇࢀࡽࡢ౫Ꮡᛶࢆ⿵ṇࡍࡿࠊ⥺㔞 II.E.2.e. ⇕⺯ග⥺㔞ィ ⇕⺯ග⥺㔞ィ 51㸦TLD㸧ࡣ࣏ࣥࢺ⥺㔞ࡢ ᐃࡸ ⋡ࡸ࢚ࢿࣝࢠ࣮ࡢ౫Ꮡᛶࡀ᭱ࡶᑠࡉ࡞ࢲ࣮࢜ in-vivo ࢻࢩ࣓ࢺࣜ⏝ࡉࢀ࡚ࡁࡓࠋTLD ࡢᙧ≧ࡣ ࢻࢆ⏝ࡍࡁ࡛࠶ࡿࠋࣅ࣮࣒ࢹ࣮ࢱྲྀᚓ࠾ࡅࡿ ࣟࢵࢻᙧࠊࢳࢵࣉᙧࠊࣃ࢘ࢲ࣮≧࡞ᵝࠎ࡛࠶ࡿࠋ ࢲ࣮࢜ࢻ᳨ฟჾࡢ⏝㛵ࡋ࡚ࡣ▩┪ࡍࡿᩥ⊩ ࣟࢵࢻᙧࢳࢵࣉᙧࡣࠊ㐺ษ⇕ฎ⌮㸦ࢽ࣮ࣜࣥ 40-43 ࡀᏑᅾࡍࡿࡢ࡛ࠊࢲ࣮࢜ࢻ᳨ฟჾࢆ⏝ࡍࡿ ࢢ㸧ࡍࡿࡇ࡛⏝ࡍࡿࡇࡀ࡛ࡁࡿࠋTLD ࡣᙉ ๓ࠊྛタ࡛㟁㞳⟽ẚ㍑ࡋ࡚ṇᖖ࡞ືసࢹ࣮ ࠸࢚ࢿࣝࢠ࣮౫Ꮡᛶࡸࣇ࢙࣮ࢹࣥࢢ⌧㇟ࠊ㠀⥺ᙧ ࢱࡢṇ☜ᛶࢆ☜ㄆࡍࡁ࡛࠶ࡿࠋ ࡞⥺㔞ฟຊࢆᣢࡘࠋࡋࡋ࡞ࡀࡽࠊࡇࢀࡽࡢຠᯝࡣ MV ࣅ࣮࣒ᑐࡋ࡚ࡣẚ㍑ⓗᑠࡉ࠸ 52, 53ࠋ⢭ᗘࡣ↷ II.E.2.c. 㓄ิᆺ᳨ฟჾ 㓄ิᆺ᳨ฟჾࡣ࣮࢜ࣉࣥࣅ࣮࣒ᑐࡋ࡚ྠ ᑕἲ ᐃἲ౫Ꮡࡋࠊs5%௨ୗࡢ⢭ᗘࢆ㐩ᡂࡍࡿ ࡇࡀ࡛ࡁ 54ࠊRadiological Physics Center ᐃࡀྍ⬟࡛࠶ࡿࡢ࡛ࠊ≉ࢯࣇࢺ࢙࢘ࢵࢪ㸦ࢲࢼ calibration laboratories ࡛ࡣs1%௨ୗࡢ⢭ᗘ࡛ࡢ ᐃ ࣑ࢵࢡ࢙࢘ࢵࢪࡸࣂ࣮ࢳ࢙ࣕࣝ࢘ࢵࢪ㸧ࡢࣉࣟࣇ ࢆ㐩ᡂࡋ࡚࠸ࡿࠋTLD ࡣࢥ࣑ࢵࢩࣙࢽࣥࢢࢹ࣮ࢱࡢ ࣝ ᐃ㐺ࡋ࡚࠸ࡿࠋ〇㐀ᴗ⪅ࡼࡗ᳨࡚ฟࢩࢫ ᐃࡣྥࡁ࡛࠶ࡿࡀࠊᑠ↷ᑕ㔝ࡸ IMRT ࡢ࣏ ࢸ࣒ࡣ㸦✵Ẽ࠶ࡿ࠸ࡣᾮయ࡛‶ࡓࡉࢀࡓ㸧㟁㞳⟽ ࣥࢺ⥺㔞ࡢ᳨ド⏝࠸ࡿࡇࡀ࡛ࡁࡿࠋ ࣞࢲ࣮࢜ࢻࣞ࡞ࡗ࡚࠸ࡿࠋ」ᩘࡢ᳨ฟ ჾࡀ┤⥺ⓗ㓄⨨ࡉࢀ࡚࠸ࡿࡓࡵࠊࢹ࣮ࢱ ᐃࢆ⾜ ࠺๓ࠊྛ᳨ฟჾࡢቑᖜ⋡ࢆỴᐃࡍࡿࡓࡵ〇㐀ᴗ⪅ ࡢᐃࡵࡓ↷ᑕ㔝ࢧࢬ࡛ឤᗘᰯṇࢆ⾜ࢃ࡞ࡅࢀࡤ II.E.2.f. ࣇ࣒ࣝ ࣇ࣒ࣝࡣගᏛ⃰ᗘࡢኚᇶ࡙ࡃ⥺㔞 ᐃ ⏝࠸ࡽࢀࡿࠋ TG-69 21 ♧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 ⓗࣇ࣒ࣝࡣ↷ᑕ㔝ࢧࢬࠊ῝ࡉࠊࣅ࣮࣒࢚ࢿࣝ ჾࡀࡼࡃ㐺ࡋ࡚࠸ࡿࠋ㟁㞳⟽ࡣࡑࡢ᭷ຠᛶࠊ౯᱁ࠊ ࢠ࣮ࠊ⌧ീᶵࡢ≧ែࡸࡑࡢࡢせᅉᙳ㡪ࢆཷࡅࡿࠋ ⢭ᗘࠊ࠸ࡸࡍࡉࡽ᭱ࡶ୍⯡ⓗ⏝ࡉࢀࡿࠋ᳨ ࣇ࣒ࣝࡣࠊࣁࣟࢤࣥ㖟ࢆྵࡴࡶࡢࠊ࢞ࣇࢡ ฟჾࡣ ᐃࢹ࣮ࢱࢆࡢࡼ࠺⏝ࡍࡿࠊ↷ᑕ㔝 ࣑ࣟࢵࢡࣇ࣒ࣝࡢ 2 ✀㢮ࡀᏑᅾࡍࡿࠋTG-69 ࢧࢬࠊศゎ⬟ࠊࢹ࣮ࢱ㞟ᚲせ࡞㛫࡞ࡢほ TG-55 55 ࡛ࡣࠊࡑࢀࡒࢀࣁࣟࢤࣥ㖟ࣇ࣒ࣝ࢞ Ⅼࡽៅ㔜㑅ᢥࡍࡿᚲせࡀ࠶ࡿࠋ࠼ࡤࠊ୍⯡ⓗ ࣇࢡ࣑ࣟࢵࢡࣇ࣒ࣝᑐࡋ࡚ᴫㄝࡉࢀ࡚࠸ࡿࠋࣁ ࡞ෆᚄ 4-6 mm ࡢ㟁㞳⟽ࡣ 4 × 4 cm2 ௨ୖࡢ↷ᑕ㔝ࢧ ࣟࢤࣥ㖟ࣇ࣒ࣝࡣගᏊ⥺ᑐࡋ࡚ᙉ࠸࢚ࢿࣝ ࢬࡢ ᐃ᭷ຠ࡛࠶ࡿࡀࠊ IMRT ࡞ᚲせࡉ ࢠ࣮౫Ꮡᛶࢆ♧ࡍࡀࠊMeV 㡿ᇦࡢ㟁Ꮚ⥺࡛ࡣẚ㍑ⓗ ࢀࡿᑠ↷ᑕ㔝࠾ࡅࡿ ᐃࡣ㐺ᙜ࡛࡞ࡃࠊ༙ᙳ㡿 ᙳ㡪ࡀᑡ࡞࠸ࠋࡇࡢ⌮⏤ࡽࣇ࣒ࣝࡣ㟁Ꮚ⥺ᑐ ᇦࡰࡅࡀⓎ⏕ࡋṇ☜ ᐃࡍࡿࡇࡣ࡛ࡁ࡞࠸ࠋ ࡋ࡚⏝ࡍࡿࡇࡀ࡛ࡁࡿ 22, 56 ࠋࣇ࣒ࣝࡼࡗ࡚ 4 × 4 cm2 ௨ୗࡢ ᐃࡣࠊከࡃࡢሙྜ࠶ࡿ⛬ᗘᑠࡉ ྲྀᚓࡉࢀࡓࣅ࣮࣒ࢹ࣮ࢱࡣ㟁㞳⟽ࡼࡿࡶࡢẚ ࡞య✚ࡢ㟁㞳⟽ࢲ࣮࢜ࢻࡀ⏝࠸ࡽࢀࡿ 64-68ࠋᑠ ࡚⢭ᗘࡀప࠸ࡶࡋࢀ࡞࠸ࡀࠊᑠ↷ᑕ㔝ࡸࢯࣇࢺ ࡉ࡞య✚ࡢ㟁㞳⟽ࡸࢲ࣮࢜ࢻࡣᑠ↷ᑕ㔝ẚ㍑ ࢙࢘ࢵࢪࡢ 2 ḟඖ⥺㔞ศᕸࢆྲྀᚓࡍࡿࡇࡀ࡛ࡁࡿࠋ ࡋ࡚↷ᑕ㔝ᑐࡋ࡚␗࡞ࡿ≉ᛶࢆ♧ࡍࡓࡵࠊࡍ Yin ࡢሗ࿌ࡢࡼ࠺ࠊᑠ↷ᑕ㔝ᑐࡋ࡚ࣇ࣒ࣝࢆ ࡚ࡢ↷ᑕ㔝ࢧࢬ࡛⏝࠸ࡿࡇࡣ࡛ࡁ࡞࠸ࠋᑠ↷ᑕ ⏝࠸ࡿሙྜࠊࣇ࣒ࣝࢫ࢟ࣕࢼࡼࡿࡰࡅࢆ⪃៖ࡍ 㔝ࡢࣉࣟࣇࣝࡣ SFD㸦Stereotactic field diodes㸧 60 ࡿᚲせࡀ࠶ࡿ ࠋ ࡸࣆ࣏ࣥࣥࢺࢳ࢙ࣥࣂ࣮ࡢࡼ࠺࡞࣐ࢡࣟᆺ᳨ ฟჾ࡛ ᐃࡍࡿᚲせࡀ࠶ࡿࠋࡇࢀࡽࡢ᳨ฟჾࡣࢩࢢ II.E.2.g. MOSFET ᳨ฟჾ ࢼࣝࡀẚ㍑ⓗᑠࡉ࠸ࡓࡵࠊSec.III.A.3.g ࡛㆟ㄽࡉࢀ 61 MOSFET ᳨ฟჾࡣ⮫ᗋ࠾ࡅࡿ ᐃ IMRT ᳨ ド 62 ࡢ⏝࠾࠸࡚Ⓨᒎࡋ࡚ࡁࡓࠋᚤᑠࢧࢬ࡛࠶ ࡿࡼ࠺ࢫ࢟ࣕࢽࣥࢢ㸦ࢧࣥࣉࣜࣥࢢ㸧㛫ࢆቑࡸ ࡋ࡚ SN ẚࢆᨵၿࡍࡿᚲせࡀ࠶ࡿࠋ ࡿࡇࡽࠊMOSFET ࡣᑠ↷ᑕ㔝ࡢ ᐃࠊᑠ⥺※ ⒪ࠊin-vivo ࢻࢩ࣓ࢺࣜ㐺ࡋ࡚࠸ࡿࠋMOSFET ࡢ ⌧ᛶࠊ┤⥺ᛶࠊ࢚ࢿࣝࢠ࣮࣭ゅᗘ౫Ꮡᛶ࡞ࡣᚑ᮶ 61 II.E.4. ᳨ฟჾࡢᛂ⟅⿵ṇ ᭷㝈ࡢయ✚ࢆࡶࡘ᳨ฟჾࡣࣉࣟࣇࣝࡢᗈࡀ ࡢ᳨ฟჾྠ➼࡛࠶ࡿ ࠋMOSFET ࡣᑑ㸦 ᐃྍ ࡾᑐࡋ࡚᭷ឤయ✚࡛ᖹᆒࡉࢀࡓᛂ⟅ࢆ♧ࡍࠋࡶࡋ ⬟࡞⥲⥺㔞㸧ࡀ▷࠸ࡓࡵࠊࣅ࣮࣒ࢹ࣮ࢱࢥ࣑ࢵࢩࣙ ᑠయ✚ࡢ᳨ฟჾࡀ࠼࡞࠸࡞ࡽࡤࠊࢹࢥ࣮ࣥ࣎ࣜࣗ ࢽࣥࢢࡣྥࡎࠊ≉ᐃࡢ࣏ࣥࢺ⥺㔞 ᐃ⏝ ࢩࣙࣥἲ㸦㏫␚ࡳ㎸ࡳ✚ศ㸧ࡀ⏝࡛ࡁࡿ 69-76ࠋ ࡉࢀࡿࠋ ᐃࡉࢀࡓࣉࣟࣇࣝࡢ᳨ฟჾࢧࢬࡼࡿ༙ᙳ 㡿ᇦࡢᗈࡀࡾࡣ detector convolution kernel ࡼࡗ࡚ II.E.2.h. Bang gel ᳨ฟჾ ㄝ࡛᫂ࡁ70-76ࠊ ┿ࡢ༙ᙳ㡿ᇦࢆ detector convolution Bang gel ᳨ฟჾ 63 ࡣ⤌ᡂࡀேయ㏆ࡃࠊ3 ḟඖ⥺ kernel ࢆ⏝࠸࡚እᤄࡍࡿࡇࡀྍ⬟࡛࠶ࡿࠋࢹࢥࣥ 㔞ศᕸࢆ㧗ศゎ⬟࡛ ᐃ࡛ࡁࡿࠋᖜᗈ࠸࢚ࢿࣝࢠ࣮ ࣮࣎ࣜࣗࢩࣙࣥἲࡣࣀࢬࡢᙳ㡪ࢆཷࡅࡸࡍࡃࠊࣀ ᑐࡋ࡚౫Ꮡᛶࡣ࡞ࡃࠊ3 ḟඖ⥺㔞ศᕸࢆ ᐃࡍࡿ ࢬࢆ㝖ཤࡍࡿᚲせࡀ࠶ࡿ 72ࠋࡇࡢၥ㢟ࡣ༙ᙳ ࡢ⌮ⓗ࡛࠶ࡿࠋ⥺㔞ศᕸࡢ࣓࣮ࢪࢆసᡂࡍࡿ detector convolution kernel ࡢ୧᪉ࡀゎᯒⓗ㛵ᩘ࡛グ ࡢ MRI ࡸ CTࠊoptical CT ࡀᚲせ࡞ࡾࠊࡇࢀࡽ ㏙࡛ࡁࢀࡤゎỴ࡛ࡁࡿࠋ༙ᙳ detector convolution ࡢീᢏ⾡ࡣ࣮ࢳࣇࢡࢺࡢᙳ㡪ࢆཷࡅࡸࡍ࠸ࠋ kernel ࡢゎᯒⓗ㛵ᩘࡣ࠸ࡃࡘࡢ◊✲ࡀ࠶ࡿࡀ ୍⯡ⓗࠊࢤࣝࢆ⏝࠸ࡓ ᐃ࡛ࡣከࡃࡢᡭ㡰ࢆᚲせ 77,78 ࡋࠊSRS ࡸ IMRT ࢆ㝖࠸࡚ࣅ࣮࣒ࢹ࣮ࢱࢥ࣑ࢵࢩ ᑠ↷ᑕ㔝ࡢ ᐃࡣ࣐ࢡࣟࢳ࢙ࣥࣂ࣮ࢆ⏝࠸ࡓ ࣙࢽࣥࢢࡣ㐺ࡉ࡞࠸ࠋ ࠺ࡀࡼ࠸ࠋࢹࢥ࣮ࣥ࣎ࣜࣗࢩࣙࣥἲࡣ」㞧࡛ࠊከ ࠊࡇࡢࡼ࠺࡞㛗࡞ࣉࣟࢭࢫࢆ㑊ࡅࡿࡓࡵࡶ ᩘࡢࣉࣟࣇࣝᑐࡋ࡚⏝࠸ࡿࡣ㛫ࡀ II.E.3. ᳨ฟჾࡢ㑅ᢥ ࢫ࢟ࣕࢽࣥࢢỈࣇࣥࢺ࣒ࢆ⏝࠸ࡓࣅ࣮࣒ࢹ࣮ ࢱ ᐃࡣ㟁㞳⟽ࠊࢲ࣮࢜ࢻࠊࢲࣔࣥࢻ᳨ฟ 26 ࡿࡓࡵࠊၟ⏝ࢯࣇࢺ࢙࢘ࡀ⏝ྍ⬟࡛࡞࠸㝈ࡾࠊ 㝈ᐃࡋࡓࢹ࣮ࢱࢭࢵࢺᑐࡍࡿ᭱⤊ⓗ࡞㑅ᢥ⫥ ࡋ࡚⏝ࡍࡁ࡛࠶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. ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢࢭࢵࢺࢵࣉ ᵝࠎ࡞⏝㏵ᛂࡌࡓᑓ⏝ࡢ᳨ฟჾࡀቑ࠼࡚ࡁࡓ 㐺ษỈࣇࣥࢺ࣒ࢩࢫࢸ࣒ࢆࢭࢵࢺࢵࣉࡍ ࡓࡵࠊ࣮ࣘࢨ࣮ࡣ᪂ࡋ࠸ࢡࢭࢧࣜ㸦᳨ฟჾࠊࢣ࣮ ࡿࡇࡣ࣮࣡ࢡࣇ࣮ࣟࡢᨵၿࡘ࡞ࡀࡿࡀࠊࡼࡾ㔜 ࣈࣝࠊࢥࢿࢡࢱࠊࢲࣉࢱ㸧᪤Ꮡࡢࢫ࢟ࣕࢽࣥࢢ せ࡞ࡇࡣࠊ㔞ࡢࢹ࣮ࢱฎ⌮ࡸ ᐃ࡞ࡘ࡞ ࢩࢫࢸ࣒ࢆ᥋⥆ࡍࡿᚲせࡀ࠶ࡿࠋࡑࡢ⤖ᯝࠊᵝࠎ࡞ ࡀࡿ᭱㐺࡛࡞࠸ࢹ࣮ࢱࢆᚓࡿྍ⬟ᛶࢆῶࡽࡍࡇ ჾලࢆ⤌ࡳྜࢃࡏ࡚⏝ࡍࡿࡇ࡞ࡾࠊ࣮ࣘࢨ࣮ ࡛࠶ࡿࠋࣇࣥࢺ࣒ࡢタ⨨ࡸࢹ࣮ࢱ㞟ࡢィ⏬ࢆ❧ ࡣࡑࢀࡽ⤫ྜࢩࢫࢸ࣒ࡢᛶ⬟ࢆ☜ㄆࡋ࡞ࡅࢀࡤ࡞ ࡚ࡿ๓ࠊࡲࡎࡣ⌧ᅾࡢࢣ࣮ࣈࣝ㓄⥺ࢆ☜ㄆࡍࡿᚲ ࡽ࡞࠸ࠋ୍⯡ⓗࡣࠊࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡈ せࡀ࠶ࡿࠋࡶࡋࠊ⌧ᅾ⏝ࡉࢀ࡚࠸ࡿࢣ࣮ࣈࣝࡀࢫ 㐺ษ࡞᳨ฟჾࡢࢱࢵࢳ࣓ࣥࢺࡀᚲせ࡞ࡿࠋ ࢟ࣕࣥ⏝࡛ࡁ࡞ࡅࢀࡤࠊ᪂ࡓࢣ࣮ࣈࣝࢆ㓄⥺ ࡍࡿᚲせࡀ࠶ࡿࠋࡲࡓࠊ⒪⨨ࡢࢥࣥࢯ࣮ࣝࣇ III.A.1. ࢫ࢟ࣕࢽࣥࢢ㸦ࣇ࣮ࣝࢻ㸧⥺㔞ィࣜࣇ ࣥࢺ࣒ไᚚ⏝ࡢ PC ࢆ୪࡚⏝ࡍࡿࡇ࡛せ ࣞࣥࢫ⥺㔞ィ ࡞ືసࡀῶࡿࡓࡵࠊࢹ࣮ࢱࡢ㞟㛫ࢆ▷ࡃࡍࡿࡇ ୍⯡ⓗࡣࠊࢫ࢟ࣕࢽࣥࢢࢱࣥࢡෆࢆࣉࣟࢢ࣒ࣛ ࡢ࠾ࡾ⛣ືࡋ࡚ ᐃࢆ⾜࠺ࣇ࣮ࣝࢻ⥺㔞ィ ࡀ࡛ࡁࡿࠋ 㸦ࡶࡋࡃࡣࢫ࢟ࣕࢽࣥࢢ⥺㔞ィ㸧ࠊ↷ᑕ㔝ෆᅛ III.A. ࢫ࢟ࣕࢼࡢ᳨ド☜ㄆ ᐃࡋ࡚ ᐃࢆ⾜࠺㸦ฟຊࡢࡤࡽࡘࡁࢆ⿵ṇࡍࡿ㸧ࣜ ㏆ᖺ⏝ࡉࢀ࡚࠸ࡿ 3D ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣ ࣇࣞࣥࢫ⥺㔞ィࡢࡘࡢ⥺㔞ィࡀࢫ࢟ࣕࢽࣥࢢ 㠀ᖖ㧗⢭ᗘ࡛ṇ☜࡛࠶ࡿࠋࡋࡋ࡞ࡀࡽ ᐃᚲせ࡞ࡿࠋࣜࣇࣞࣥࢫ⥺㔞ィࢆ⏝࠸ࡿࡇ Mellenberg ࡽ 79 33 ࡸࠊHumphries Purdy ࡀᥦࡋ ࡛ฟຊࡢ▐㛫ⓗ࡞ኚືࡸࢻࣜࣇࢺࢆ㝖ཤࡍࡿࡇ ࡓࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢᇶᮏⓗ࡞ QA ࡣ⾜࠺ࡁ ࡀ࡛ࡁࡿࡓࡵࠊࡍ࡚ࡢ ᐃ࠾࠸࡚⏝ࡍࡿࡇ ࡛࠶ࡿࠋᐃᮇⓗࠊᑡ࡞ࡃࡶỈࣇࣥࢺ࣒ࡢ⏝ ࢆᙉࡃ᥎ዡࡍࡿࠋ ๓ࡣ࣮࣒ࡀ xࠊyࠊzࠊᑐゅ⥺᪉ྥ⮬⏤ືࡃ ࣇ࣮ࣝࢻ⥺㔞ィࣜࣇࣞࣥࢫ⥺㔞ィࡣࠊࢫ࢟ ࡇࢆ☜ㄆࡍࡿࡇ࡛ရ㉁ࢆಖドࡍࡿࡇࡀ࡛ࡁ ࣕࣥࡢṇ☜ࡉ⌧ᛶࢆಖࡘࡓࡵࠊ≉ὀࡶࡋࡃࡣ ࡿ࡛࠶ࢁ࠺ࠋࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢ〇㐀ᴗ⪅ࡣᖺ ᑓ⏝ࡢಖᣢල࡛ᚲࡎᅛᐃࡋ࡞ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋᩓ ୍ᅇ⾜ࢃࢀࡿࡁண㜵ⓗ࣓ࣥࢸࢼࣥࢫࢧ࣮ࣅࢫ ⥺ࡀ ᐃࢹ࣮ࢱࡢ⢭ᗘにᙳ㡪ࢆཬࡰࡍࡢ࡛ࠊ㔠ᒓ〇ࡢ ࢆᥦ౪ࡋ࡚࠸ࡿࠋࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢṇ☜ࡉ ಖᣢලࡣ㑊ࡅࡿࡁ࡛࠶ࡿࠋ⏝ࡍࡿ⥺㔞ィࢫ࢟ ┤⥺ᛶࡣ㛗࠸㊥㞳ࢆ㉮ᰝࡋ࡚ࢳ࢙ࢵࢡࡍࡁ࡛࠶ ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢ〇㐀ᴗ⪅ࡀ␗࡞ࡿሙྜࡣࠊ᪂ࡋ ࡿࠋࢥ࣑ࢵࢩࣙࢽࣥࢢ⏝ࡢࣅ࣮࣒ࢹ࣮ࢱࢆ ᐃࡍࡿ ࠸⥺㔞ィࡢ〇㐀ᴗ⪅ࡀసᡂࡋࡓ㐺ษ࡞ࢲࣉࢱࢆ ๓ࡣࠊ᥋⥆ࢣ࣮ࣈࣝࡢ₃㟁ࡸ⌧ᛶྠᵝࠊࢫ ⏝ࡍࡁ࡛࠶ࡿࠋỈ୰ࡢ⥺㔞ࢆ ᐃࡍࡿ㝿ࠊ⥺ ࢟ࣕࢽࣥࢢࢱࣥࢡࡢ≀⌮ⓗ࡞≧ែ㸦Ỉࡢ₃ࢀࡸࠊࡦ 㔞ィࢆࢸ࣮ࣉࡸῧ࠼ᮌ࡛ᅛᐃࡍࡿࠊᅛᐃࡀ⦆ࡃ࡞ 33 ࡧ㸧ࡸᶵᲔⓗ࡞Ᏻᐃᛶࢆ☜ㄆࡍࡿࡁ࡛࠶ࡿ ࠋ ࡗ࡚ࡋࡲ࠺ࡓࡵࠊ⌧ᛶࡢప࠸ࢹ࣮ࢱࢆ㞟ࡋ࡚ࡋ ࡍ࡚ࡢ㒊ရࡀྠࡌ〇㐀ᴗ⪅ࡼࡗ࡚సࡽࢀ࡚ ࡲ࠺ࡇ࡞ࡾࠊࢥ࣑ࢵࢩࣙࢽࣥࢢࡢ㛫ࡀቑຍࡍ ࠸ࡿࢩࢫࢸ࣒ࡢሙྜࠊ୍⯡ⓗࡣⰋዲ࡞ࢹ࣮ࢱࡀ ࡿࡓࡵ⾜ࡗ࡚ࡣ࡞ࡽ࡞࠸ࠋ 㞟࡛ࡁࡿ⤌ࡳྜࢃࡏࡔ⪃࠼ࡽࢀࡿࡀࠊ࣮ࣘࢨ࣮ࡣ ࣜࣇࣞࣥࢫ⥺㔞ィࡣࣇ࣮ࣝࢻ⥺㔞ィࡢࢫ࢟ ⏝๓ලྜࡸ㏻ಙ࢚࣮ࣛࡢ᭷↓ࢆ☜ㄆࡍࡿ ࣕࣥ⠊ᅖୖࡣタ⨨ࡋ࡚ࡣ࡞ࡽ࡞࠸ࠋࣜࣇࣞࣥࢫ ࡁ࡛࠶ࡿࠋࡉࡽࠊỈᵴྠࡌ〇㐀ᴗ⪅ࡀ㈍ࡋ࡚ ⥺㔞ィࡀࣇ࣮ࣝࢻ⥺㔞ィࡢࢫ࢟ࣕࣥ⠊ᅖୖࡁ ࠸ࡿ㒊ရ㸦≉᳨ฟჾ㸧࠾࠸࡚ࡶࠊࡑࢀࡒࢀ ࡚ࡋࡲ࠺ࡼ࠺࡞ᑠࡉ࡞↷ᑕ㔝ࡢሙྜࡣࠊࣜࣇࣞ 80 ᛶࡀ࡞࠸ሙྜࡶ࠶ࡿࠋSchmid Morris ࡀ㛤Ⓨ ࣥࢫ⥺㔞ィࢆ⏝ࡍࡿ௦ࢃࡾࠊࢫ࢟ࣕࣥ㛫ࢆ㛗 ࡋࡓࡼ࠺࡞ࠊࢫ࢟ࣕࢼ⒪⨨ࢆྠᮇࡉࡏࡿࡇ ࡃࡋ࡚ࢹ࣮ࢱ㔞ࢆቑࡸࡍ᪉ἲࡀ⏝࠸ࡽࢀࡿࠋ ࡼࡾ↷ᑕ㔝࡞ࢆ⮬ືኚࡉࡏࡿࢩࢫࢸ࣒ࡣ ࣜࣇࣞࣥࢫ⥺㔞ィࣇ࣮ࣝࢻ⥺㔞ィࡢ✀㢮 ṇ☜ືసࡍࡿࢆヨ㦂ࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋࡇࡢ ࡣ๓㏙㸦II.E.3.㸧ࡢࡼ࠺ࠊ ᐃࡍࡿࣅ࣮࣒ࢹ࣮ࢱ ࡼ࠺࡞ᮍ᮶ⓗ࡞ࢩࢫࢸ࣒ࡣၟ⏝⨨࡛ࡣࡲࡔ⏝ ࡢ⏝㏵ᛂࡌ࡚㑅ࡪࡁ࡛࠶ࡿࠋࡲࡓࠊࡘࡢ⥺㔞 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 with correct 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࠾ࡃࡇࢆ᥎ ࢽࣥࢢࢩࢫࢸ࣒᥋⥆ࡍࡿሙྜࡣୗグࡢⅬࡘ࠸ ዡࡍࡿࠋࢹ࣮ࢱ㞟୰᳨ฟჾࢆኚ᭦ࡋࡓሙྜࡸࠊ ࡚⪃៖ࡋ࡞ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋ 㟁ィࡢ㟁※ࢆධࢀࡿ๓ࡣࠊࣂࢫࡢᚲせ᮲௳ ࡢ☜ㄆࡀᚲせ࡛࠶ࡿࠋㄗࡗࡓࣂࢫ࡛⏝ࡍࡿ III.A.1.a. ᳨ฟჾࡢಖᣢල ୍⯡ⓗࠊࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࢭࢵࢺ࡛㈍ ᳨ฟჾࢆᦆയࡍࡿྍ⬟ᛶࡀ࠶ࡿࠋFig. 2 ࡣ₃㟁ࡀ㉳ ࡁ࡚࠸ࡿ㟁㞳⟽ṇᖖືసࡍࡿ㟁㞳⟽࡛ࠊタᐃࢤ ࡉࢀࡿ᳨ฟჾࡣ㛗㍈ࡢ㛗ࡉෆᚄࡀࡰྠࡌᑍἲ ࣥࡀṇࡋ࠸ሙྜṇࡋࡃ࡞࠸ሙྜࡢ PDD ࢆ♧ࡋ ࡛࠶ࡿࠋࡶࡋࡑ࠺࡛࡞࠸ሙྜࡣࠊ㉮ᰝ᪉ྥࢆỴᐃ ࡚࠸ࡿࠋࢫ࢟ࣕࣥࢹ࣮ࢱࡀ␗ᖖ࡞ࣃࢱ࣮ࣥࢆ♧ࡍሙ ࡍࡿ㝿᳨ฟჾࡢᑍἲࡢᙳ㡪ࢆ⪃៖ࡍࡁ࡛࠶ࡿࠋ ྜࡸࠊࢫࣃࢡ≧ࢆ♧ࡍሙྜࡣࠊࣂࢫࡸࢤࣥ ࡲࡓࠊ᳨ฟჾࡢᑍἲࡣูࠊ㉮ᰝ᪉ྥࢆ⪃៖ࡋ࡞ ࡀ㐺ษ࡛࡞࠸ྍ⬟ᛶࡀ࠶ࡿࠋࢫ࢟ࣕࣥ୰ࡑࡢࡼ࠺ ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋࣅ࣮࣒ࡢ୰ᚰ㍈㛵ࡋ࡚ࠊ᳨ฟჾ ࡞⌧㇟ࡀ㉳ࡁࡓሙྜࡣࠊࡍࡄ ᐃࢆ୰Ṇࡋࠊ᳨ฟ ࡢ㛗㍈ࡣ 3 ࡘࡢ᪉ྥタ⨨ྍ⬟࡛࠶ࡿࠋ(1) 㛗㍈ࡣ ჾࡢࣂࢫࡀ㐺ษࢳ࢙ࢵࢡࡍࡁ࡛࠶ࡿࠋ 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ᅽࣂࢫࡢ ჾࡢྥࡁࡣࣉࣟࣇࣝࡸ༙ᙳ㒊ศࡢ ᐃ࡛㔜せ ᴟᛶࡼࡾỴᐃࡉࢀࠊࡶࡋ㧗㟁ᅽࣂࢫࡢไᚚࡀ ࡞ࡾࠊSec. IV A 4 a.࡛㆟ㄽࡉࢀࡿࠋ᳨ฟჾࡣࠊ㉮ 㟁ィ࡛⾜ࢃࢀ࡚࠸ࡿࡢ࡛࠶ࢀࡤၥ㢟ࡣ࡞࠸ࠋࡋ ᰝ᪉ྥᑐࡋ࡚᭱ᑠࡢయ✚࡞ࡿࡼ࠺タ⨨ࡍ ࡋࠊࢲ࣮࢜ࢻ᳨ฟჾࡢಙྕࡢᴟᛶࡣࠊ᳨ฟჾࡢᵓ ࡁ࡛࠶ࡿࠋࣅ࣮࣒㍈ᖹ⾜タ⨨ࡍࡿሙྜࡣ₃㟁ࡸ 㐀౫Ꮡࡍࡿࠋ〇㐀ᴗ⪅ࡣྠᵝࡢࣔࢹࣝࡢࢲ࣮࢜ 㟁㞳య✚እຠᯝ㸦Sec. III D 4 ࡛㆟ㄽࡉࢀࡿ㸧ࡘ࠸ ࢻ᳨ฟჾᑐࡋ࡚୧᪉ࡢᴟᛶࢆᥦ♧ࡋ࡚ࡃࡿྍ⬟ ࡚⪃៖ࡍࡁ࡛࠶ࡿࠋ ᛶࡀ࠶ࡿࠋࡑࡢࡓࡵ࣮ࣘࢨ࣮ࡣࢲ࣮࢜ࢻ᳨ฟჾࢆ ㉎ධࡍࡿ㝿ࡣࠊᡤ᭷ࡢ㟁ィ࡛⏝࡛ࡁࡿᴟᛶ☜ III.A.1.b. ༳ຍ㟁ᅽ㸦ࣂࢫ㸧 ࢇࡢ㟁㞳⟽⥺㔞ィࡣ 300 V ࡽ 400 V ࡢ㛫 ㄆࡋ࡞ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋ୍⯡ⓗࠊࢇࡢ᳨ฟ ჾࡣࡕࡽࡢᴟᛶ࡛࠶ࡗ࡚ࡶ⏝ࡍࡿࡇࡣ࡛ࡁ ࡢ㟁ᅽ࡛⏝ࡉࢀࡿࠋ୍᪉ࠊࢲ࣮࢜ࢻ᳨ฟჾࡢሙ ࡿࡀࠊ࣮ࣘࢨ࣮ࡣࡕࡽࡢᴟᛶ࡛ࡶ್ࡀ୍⮴ࡋ࡚࠸ ྜࠊ㟁ᅽࡣ 0 V タᐃࡋ࡞ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋࢲ ࡿࡇࢆ☜ㄆࡋ࡞ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋFig. 3 ࡣᵝࠎ࡞ ࣔࣥࢻ⥺㔞ィࡣ୍⯡ⓗ 100 V ࡛⏝ࡉࢀࡿࠋ᳨ฟ ᳨ฟჾ࠾࠸࡚ᴟᛶࡀ㸩ࡢሙྜ㸫ࡢሙྜᚓࡽ ჾࢆ㟁ィ᥋⥆ࡍࡿ๓ࠊ࣮ࣘࢨ࣮ࡣ᳨ฟჾࡢࢱ 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) ࡞࠸ࡇࢆពࡋ࡚࠾ࡾࠊࡑࡢሙྜࡣࡕࡽࡢᴟᛶ ࡛ࡶ ᐃࡀྍ⬟࡛࠶ࡿࡀࠊᗄࡘࡢ᳨ฟჾࡣࡁ࡞ ᕪࢆ♧ࡋࡓࠋKim ࡽ 81 ࡣప⥺㔞⋡ࡢ ᐃࡢ㝿ࡶࠊ ᣦ㢌ᙧ㟁㞳⟽ࡢᴟᛶຠᯝࢆホ౯ࡍࡿᚲせࡀ࠶ࡿࡇ ࢆⓎ⾲ࡋࡓࠋ୍⯡ⓗࡣࠊᴟᛶࡼࡾⱝᖸࡢ㐪࠸ ࡀ㉳ࡇࡿࡇࡣணࡉࢀࡿࡀࠊᴟᛶࡼࡿᕪࡣ 0.5% ௨ෆᢚ࠼ࡿࡁ࡛࠶ࡿࠋࢹ࣮ࢱ㞟ࡣࠊ⧞ࡾ㏉ࡋ ᐃ࠾࠸࡚⌧ྍ⬟࡞୍㈏ࡋࡓ୍ࡘࡢᴟᛶ࠾ ࠸࡚⾜࠺ࡇࢆ່ࡵࡿࠋFig. 3 ࡛♧ࡋࡓࡼ࠺ࠊ୍ FIG. 4. BNC, TNC, and components of the triaxial cable. ࡘࡢᴟᛶ࡛ࡍ࡚ࡢ ᐃࢆ⾜࠸ࠊᴟᛶຠᯝࡢᙳ㡪ࡀ ᑠࡉ࠸᳨ฟჾࢆ⏝࠸ࡿࡇ࡛ࠊయࡢㄗᕪࢆపࡃᢚ ࣮ࡼࡾᛂ⟅ࡀኚࡍࡿࡓࡵࠊ ᐃ್ᙳ㡪ࢆཬࡰ ࠼ࡿࡇࡀ࡛ࡁࡿࠋ ࡍࠋࢲ࣮࢜ࢻ᳨ฟჾࡢ࢚ࢿࣝࢠ࣮ᛂ⟅ࡣ 6 MV ග Ꮚ⥺ࠊ↷ᑕ㔝 4040 cm2 ࡢ᮲௳࡛ PDD ࢆ ᐃࡋࠊ III.A.1.d. ⤖ྜ ࢜ࣥ⤖ྜࡣ㧗㟁ᅽ㸦300 V ௨ୖ㸧࡛⏝ࡍࡿ 㟁㞳⟽⥺㔞ィࡢ PDD ẚ㍑ࡍࡿࡇ࡛☜ㄆ࡛ࡁࡿࠋ ࢫ࢟ࣕࣥ⏝ࡢ㟁㞳⟽࡛ࡣ≉ၥ㢟࡞࠸ࡀࠊ〇㐀ᴗ⪅ ࡶࡋࠊࢲ࣮࢜ࢻ᳨ฟჾ࡛ ᐃࡋࡓ PDD ࡢഴࡁࡀ ࡀ᥎ዡࡋ࡚࠸ࡿ㟁ᅽࡢタᐃࡣ☜ㄆࡋ࡚࠾ࡃࡁ࡛ 㟁㞳⟽⥺㔞ィ࡛ ᐃࡋࡓࡶࡢࡼࡾࡶ⦆ࡸ࡛࠶ࢀ ࠶ࡿࠋࡲࡓࠊ㟁㞳య✚ࡢᑠࡉ࡞㟁㞳⟽ࡢሙྜࠊᶆ‽ ࡤࠊࡑࢀࡣ࢚ࢿࣝࢠ࣮ᛂ⟅ࡢኚࢆ⾲ࡋ࡚࠸ࡿࠋ୍ ⓗ࡞ 300 V ࡼࡾప࠸㟁ᅽࡀ᥎ዡࡉࢀ࡚࠸ࡿሙྜࡀ࠶ ⯡ⓗࠊ᳨ドࡼࡗ࡚≉ᐃࡢ⿵ṇἲࡀጇᙜ࡛࠶ࡿ ࡿࠋࡶࡋྍ⬟࡛࠶ࢀࡤࢫ࡛࢟ࣕࣥ⏝ࡍࡿ⥺㔞⋡࡛ࠊ ㄆࡵࡽࢀ࡞࠸㝈ࡾࡣࠊࢲ࣮࢜ࢻ᳨ฟჾࡣ↷ᑕ㔝 82 ༳ຍ㟁ᅽࢆ᥎ዡࡢ༙ศࡢ್ࡋ࡚⤖ྜຠᯝ ࢆ☜ ࡢ PDD ࡢ ᐃࡣ⏝ࡍࡁ࡛ࡣ࡞࠸ࠋ ㄆࡋࠊ⤖ྜ⿵ṇࡢᚲせࡀ࡞࠸ࡇࢆ☜ㄆࡍࡁ࡛ ࠶ࡿࠋ III.A.2. ࢣ࣮ࣈࣝࠊࢥࢿࢡࢱࠊࢲࣉࢱ 㧗⢭ᗘ࡞ࢹ࣮ࢱ ᐃࢆ⾜࠺ࡓࡵࡣࠊ㧗ရ㉁࡞ࢣ III.A.1.e. ឤᗘ ࣮ࣈࣝ㟁ィࡀᚲせ࡞ࡿࠋࡶࡋࡑࢀࡽࢆ⏝ࡋ ᳨ฟჾࡢឤᗘࡣᚲࡎࠊጇᙜ࡞ SN ẚ࡛ࠊࡘಙྕ ࡞ࡅࢀࡤࠊᵝࠎ࡞せᅉࡼࡾ ᐃ್ࡣ☜࡞ࡶࡢ ࡀ㣬ࡋ࡞࠸⛬ᗘࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋࢫ࢟ࣕࣥ ࡞ࡿࠋࡑࢀࡽࡢせᅉࡢ࠸ࡃࡘࡣࢣ࣮ࣈࣝࡢ㸦ಙ ࢆ⾜࠺๓ࠊ᳨ฟჾࡢឤᗘ㐺ࡋࡓ㟁ィࡢ ᐃࣞ ྕ㸧ᛅᐇᗘࡸࢥࢿࢡࢱࡢရ㉁ࠊࢲࣉࢱ࡞ࡢ㐺 ࣥࢪࢆ☜ㄆࡋ࡚࠾ࡃࡁ࡛࠶ࡿࠋ᳨ฟჾࡢឤᗘࡣࠊ ྜᛶ㛵ಀࡀ࠶ࡿࠋ࣮ࣘࢨ࣮ࡣ௨ୗࡢ❶࡛㏙ࡿ ᳨ฟჾࡢ〇㐀ᴗ⪅ࡽධᡭ࡛ࡁࡿࠋࡲࡓࠊࣜࣇࣞ ᵝࠎ࡞ࢱࣉࡢࢥࢿࢡࢱ㛵ࡍࡿ▱㆑ࡀᚲせ࡞ ࣥࢫ⥺㔞ィࣇ࣮ࣝࢻ⥺㔞ィࡢឤᗘࡣྠ⛬ᗘ ࡿࠋ ࡍࡁ࡛࠶ࡿࠋࢫ࢟ࣕࣥ⏝ࡢࢯࣇࢺ࢙࢘ࡣࠊࣜ ࣇࣞࣥࢫࣇ࣮ࣝࢻࡢ㟁ィࡢಙྕࡀᆒ➼ ࡞ࡿࡼ࠺⮬ືⓗࢤࣥࢆㄪᩚࡍࡿࡶࡢࡶ࠶ࡿࠋ↷ III.A.2.a. BNC ࢥࢿࢡࢱ࠾ࡼࡧ TNC ࢥࢿࢡࢱ BNC 㸦ࡂ∎ᘧ Bayonet Neill - Concelman㸧ࡣ ᑕ㔝ࢧࢬࢆኚ࠼ࡓ㝿ࢤࣥࡢ☜ㄆࢆ⾜࠺ࡇ ࡑࡢⓎ᫂⪅ࡕ࡞ࢇ࡛ྡ࡙ࡅࡽࢀ࡚࠾ࡾࠊ∎ࢆࡦࡡ ࡣ㔜せ࡛ࠊᙜ↛ࠊ࣮࢜ࣉࣥ↷ᑕ㔝ࡽ࢙࢘ࢵࢪ↷ᑕ ࡾ࡞ࡀࡽࢫࢺࢵࣃ࣮╔ࡍࡿࢱࣉࡢࢱࢵࢳ 㔝ኚ᭦ࡋࡓሙྜࡣࢤࣥࡢㄪᩚࡀᚲせ࡞ࡿࠋ ࣓ࣥࢺࢆᣢࡘࠋࡇࢀࡣࠊ2 ㍈࠾ࡼࡧ 3 ㍈ࡢ୧᪉ᑐ ࡋ࡚〇㐀ࡉࢀ࡚࠸ࡿࠋTNC 㸦ࡡࡌᒣᘧ Threaded III.A.1.f. ࢚ࢿࣝࢠ࣮ᛂ⟅ Neill-Concelman㸧ࡣ BNC ࡢࡡࡌᒣᘧ࡛࠶ࡿࠋ୧⪅ ୍⯡ⓗࠊ㟁㞳⟽⥺㔞ィࡢ㧗࢚ࢿࣝࢠ࣮ගᏊ⥺ ࡶ⥺㔞 ᐃࡼࡃ⏝࠸ࡽࢀࠊከᑡࡢ័ࢀࡀᚲせ࡛ ᑐࡍࡿ࢚ࢿࣝࢠ࣮ᛂ⟅ࡣࡰ୍ᐃ࡛ࠊ≉⿵ṇࢆ⾜ ࠶ࡿࠋFig. 4 ᥋⥆㒊ศࡢࢆ♧ࡋࡓࡀࠊBNC TNC ࠺ᚲせࡣ࡞࠸ࠋ୍᪉ࠊࢲ࣮࢜ࢻ᳨ฟჾࡣ࢚ࢿࣝࢠ 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≉ᣓᘼෆࡢᣲࡆࡓࡶࡢࡣࠊࢫ࢟ࣕࢽࣥࢢ ࢱࣥࢡ࡛⏝ࡉࢀࡿ᳨ฟჾ㟁ィࢆ᥋⥆ࡍࡿ㒊 ศᗈࡃ⏝ࡉࢀ࡚࠸ࡿࠋ࠶ࡿ〇㐀ᴗ⪅ࡣࠕ3 ㍈ᆺࠖ ࢆᨵⰋࡋࡓࢥࢿࢡࢱࢆ᥇⏝ࡋ࡚࠾ࡾࠊࡇࡢࢥࢿࢡࢱ ࡢぢࡓ┠ࡣ 2 ㍈ࡔࡀࠊ㟁ᴟࡀࢥࢿࢡࢱෆⶶࡉࢀ࡚ ࠸ࡿࠋࢥࢿࢡࢱࡢヲ⣽ࡘ࠸࡚ࡣ〇㐀ᴗ⪅㸦CNMC ♫ࠊStandard Imaging ♫ࠊ PTW ♫ࠊ Wellhöfer ♫࡞ 㸧ࡽ☜ㄆ࡛ࡁࡿࠋ࠶ࡽࡌࡵ〇㐀ᴗ⪅ࡈࡢࢥ ࢿࢡࢱࡢᙧ≧ࢆᢕᥱࡋ࡚࠾ࡃࡇࡼࡾࠊᑗ᮶〇㐀 FIG. 5. Effect of cable length in radiation beam. The cables are of ᴗ⪅ࡽ᪂ࡋ࠸᳨ฟჾࢆ㉎ධࡍࡿሙྜᙺ❧ࡘࠋ different types from various manufacturers. x ࢜ࢫ: ୰ᚰࡢᑟ⥺ࡀࣆࣥ≧ࡢࡶࡢ x ࣓ࢫ: ୰ᚰࡢᑟ⥺ࡀࢯࢣࢵࢺ࣮࣍ࣝ≧ࡢࡶࡢ x 3 ㍈: 3 ᮏࡢఏᑟయࡀྠᚰ≧㓄⨨ࡉࢀࡓࠊࢣ࣮ ᥋⥆ࡢ㝿᭱ࡶⰋࡃ㉳ࡁࡿㄗࡾࡣࠊ2 ㍈ࡢ BNC ࢥࢿ ࣈࣝࡶࡋࡃࡣࢥࢿࢡࢱ ࢡࢱ 3 ㍈ࡢ BNC ࢥࢿࢡࢱࢆ↓⌮ࡸࡾ⧅ࡆࡿࡇ 2 ㍈: 2 ᮏࡢఏᑟయࡀྠᚰ≧㓄⨨ࡉࢀࡓࠊࢣ࣮ ࡛࠶ࡿࠋࡇࡢሙྜࠊ(1) ࢥࢿࢡࢱ㒊ศࡀ◚ᦆࡍࡿࠊ ࣈࣝࡶࡋࡃࡣࢥࢿࢡࢱ (2) ࢲࣉࢱ: ␗࡞ࡿ✀㢮ࡢࢥࢿࢡࢱྠኈࢆ᥋⥆ࡍ ࡋ᳨࡚ฟჾࡸ㟁ィࡀ◚ᦆࡍࡿࠊ࡞ࡢ㔜࡞ᨾ ࡿࡓࡵࡢࠊኚ⏝ࢥࢿࢡࢱࡶࡋࡃࡣ▷࠸ࢣ࣮ࣈ ࡀ㉳ࡁࡿࠋࡲࡓࠊࢣ࣮ࣈࣝࢆࡡࡌࡿࠊ᭤ࡆࡿࠊຊࢆ ࣝ ຍ࠼ࡿ࡞ࡢ⾜Ⅽࡣࢩ࣮ࣙࢺࡢཎᅉ࡞ࡿࡓࡵࠊ⤯ x x 㟁ィࡢ㧗㟁ᅽࡀㄗࡗࡓ᥋⥆ࡼࡾࢩ࣮ࣙࢺ ᑐ⾜ࡗ࡚ࡣ࡞ࡽ࡞࠸ࠋ㐺ษ࡞⤌ࡳྜࢃࡏ࡛ࡶಙ III.A.2.b. ୍⯡ⓗ࡞᥋⥆࢚࣮ࣛ ࢇࡢ⥺㔞 ᐃ࠾ࡼࡧࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ ྕࢆྲྀᚓࡍࡿࡇࡀ࡛ࡁࡿࡶࡋࢀ࡞࠸ࡀࠊࡑࡢࡼ ࠺࡞ಙྕࡣ⌧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⏝ࡢࢲࣉࢱࡀ ㉁ࡸྲྀᢅ≧ἣࠊ⥔ᣢ≧ែࡼࡾ୍ᐃ㔞ࡢ₃ࢀ㟁ὶࡀ ᚲせ࡞ࡿࠋPTW ♫ࡣ≉Ṧ࡞ 3 ㍈ࢣ࣮ࣈࣝࢆ᥇⏝ࡋ Ⓨ⏕ࡍࡿࠋࡁࡘࡃࡡࡌ᭤ࡆࡽࢀࡓࢣ࣮ࣈࣝࢆ⏝ࡋ ࡚࠸ࡿᴗ⪅ࡢ୍ࡘ࡛࠶ࡿࠋࢲ࣮࢜ࢻࡢሙྜࠊࣀ ࡓሙྜࠊࣀࢬࡀⓎ⏕ࡍࡿࠋࡓ࠸࡚࠸ࡢᕷ㈍ࢣ࣮ࣈ ࣮ࢻ࢝ࢯ࣮ࢻࡢ 2 ࡘࡢ㟁ᴟࡀ࠶ࡾࠊ2 ㍈ࢣ࣮ࣈࣝ ࣝࡢ₃ࢀ㟁ὶࡣ 10í13–10í14 A ⛬ᗘ࡛࠶ࡿ 83-85ࠋࢣ࣮ ࡀᚲせ࡞ࡿࠋ㟁㞳⟽⥺㔞ィࡢሙྜ 3 ࡘࡢ㟁ᴟ㸦㞟 ࣈࣝࡢ᭤ࡆࠊࡡࡌࡾࠊ㞧࡞ಖ⟶࡞ࡼࡾࠊ₃ࢀ 㟁ᴟࠊ࣮࢞ࢻࠊHV ࣂࢫ㸧ࡀ࠶ࡿࡓࡵࠊ3 ㍈ࢣ 㟁ὶࡣ᫂ࡽࡁࡃ࡞ࡿࠋᑠ↷ᑕ㔝ࡸ↷ᑕ㔝እࡢ ࣮ࣈࣝࡀᚲせ࡞ࡿࠋࢲ࣮࢜ࢻ᳨ฟჾࡢሙྜࠊ㐺 ᐃࡢ㝿ࡣࠊ ᐃࡢಙྕẚࣀࢬࡀከࡃ࡞ࡾ ษ࡞ࢲࣉࢱࢆ⏝ࡍࡿࡇࡼࡾ 3 ㍈ࢣ࣮ࣈࣝࢆ ࠺ࡿࠋ₃ࢀ㟁ὶࡣ୍⯡ⓗࠊࢣ࣮ࣈࣝࡢရ㉁ࠊ↷ᑕ ⏝࡛ࡁࡿࡀࠊ㟁㞳⟽⥺㔞ィ 2 ㍈ࢣ࣮ࣈࣝࡣ᥋⥆ ࡉࢀ࡚࠸ࡿࢣ࣮ࣈࣝࡢ㛗ࡉࠊࢥࢿࢡࢱ౫Ꮡࡍࡿࠋ ࡍࡿࡇࡣ࡛ࡁ࡞࠸ࠋࡉࡽࠊ㟁㞳⟽⥺㔞ィࢆ⏝ ࠸ࡃࡘࡢ㟁ィࡣࠊ㞽Ⅼㄪᩚࡼࡾ₃ࢀ㟁ὶࢆ࢜ ࡍࡿሙྜࡣ㧗㟁ᅽࢆ༳ຍࡍࡿࡓࡵࠊேࡸ㟁Ꮚᶵჾ ࣇࢭࢵࢺࡍࡿࡇࡀ࡛ࡁࡿࠋ㞽Ⅼㄪᩚࡣࣅ࣮࣒࢜ࣇ ឤ㟁ࡍࡿࡇࡀ࡞࠸ࡼ࠺ᚲࡎὀពࢆࡋ࡞ࡅࢀࡤ ࡢ≧ែ࡛⾜࠺ࡁ࡛࠶ࡿࠋ᳨ฟჾ࣐࢘ࣥࢺࡢྥࡁ ࡞ࡽ࡞࠸ࠋࡲࡓࠊࢣ࣮ࣈࣝ࡞ࢆ᥋⥆ࡍࡿ㝿ࡣ㟁ᅽ ࡼࡗ࡚↷ᑕࡉࢀࡿࢣ࣮ࣈࣝࡢ㛗ࡉࡀኚࢃࡿࡓࡵࠊ₃ ࢆⴠࡋࡓ≧ែ࡛⾜ࢃ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋ ࢀ㟁ὶࡢ㔞ᙳ㡪ࢆ࠼ࡿࠋ 㟁㞳⟽⥺㔞ィ⏝ࡢ㟁ィࢲ࣮࢜ࢻ᳨ฟჾࡢ 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ෆධࡿࢣ࣮ࣈࣝࡢ㛗ࡉࡼࡿ ᐃ್ࡢኚࢆ♧ࡋ࡚࠸ࡿࠋDas ࡽ 86 ࡣࠊ㟁Ꮚ⥺ࡢ ➃Ꮚࡢ㟁ᅽࡣྠࡌࡑࢀ㏆࠸ࠋࡶࡋࠊ1 mV ⛬ᗘ ࡢධຊ࢜ࣇࢭࢵࢺ㟁ᅽࡀ⏕ࡌࡿࠊ㟁㞳⟽⥺㔞ィ ᐃࡣ↷ᑕ㔝ෆධࡿࢣ࣮ࣈࣝࡢ㛗ࡉࡀ ᐃ ࠾࠸࡚₃ࢀ㟁ὶࡢࡼ࠺࡞ຠᯝࢆ⏕ࡌࡿࠋࡶࡋࠊࢲ ್㔜࡞ᙳ㡪ࢆཬࡰࡍሗ࿌ࡋ࡚࠸ࡿࠋࡑࡢࡓࡵࠊ ࣮࢜ࢻ᳨ฟჾ࡛ ᐃࢆ⾜࠺ࠊධຊ࢜ࣇࢭࢵࢺࡼ ࢣ࣮ࣈࣝࡀ↷ᑕ㔝ෆᗈ࠸⠊ᅖ࡛ྵࡲࢀࡿሙྜࠊ≉ ࡾ┤᥋ㄞࡳ್್ࡀຍ࠼ࡽࢀ࡚ࡋࡲ࠺ࠋ ู࡞⪃៖ࡀᚲせ࡞ࡿࠋࢫ࢟ࣕࣥࢆ⾜࠺๓ࠊỈ୰ ධࡿࢣ࣮ࣈࣝࡢ᳨ฟჾ㏆࠸㒊ศയࡸࠊࡁࡘࡃ III.A.3.d. 㐃⥆ᛶ ᭤ࡀࡿ㒊ศࡀ࡞࠸ㄪ࡚࠾ࡃࡁ࡛࠶ࡿࠋࢣ࣮ࣈ ᑠయ✚ࡢ㟁㞳⟽ࡣప࠸ࣂࢫ㟁ᅽ࡛ࡶ࢜ࣥ ࣝࡢ‴᭤ࡸᑠࡉ࡞യࡣ᩿⥺ࡢཎᅉ࡞ࡾࠊ⤯⦕ㄏᑟ ࡀ㞟ࡉࢀࡿ࠸࠺ၥ㢟ࡀ࠶ࡿࠋᩘ mV ࡢ࣮࢞ࢻ యࡸࣀࢬపῶᮦࡀࢲ࣓࣮ࢪࢆཷࡅࡓሙྜྠᵝ 㟁ᴟࡢ㛫⏕ࡌࡿ⛬ᗘࡢ㟁ᅽ࡛ࡶࠊ㣬ࡋ࡞࠸⛬ᗘ ࡛ࠊỈỿࡵ࡚ ᐃࢆ⾜࠺㟁ィ㟁Ẽⓗ࡞ၥ㢟 ࡢ࢜ࣥࡢ㞟ࡀྍ⬟࡛࠶ࡿࠋࡇࡢ⛬ᗘࡢ㟁ᅽࡣࠊ ࢆ㉳ࡇࡍࠋ 㟁ィࡢ࣮࢞ࢻ㟁ᴟ㛫ࡢධຊ࢜ࣇࢭࢵࢺࡋ࡚ Ꮡᅾࡍࡿࠋࡑࡢࡓࡵࠊࣂࢫ㟁ᅽࡀṇ☜༳ຍࡉ III.A.3. 㟁ィ ࢀ࡚࠸࡞࠸ሙྜࡸࠊ㟁㞳⟽ࡢ㧗ᅽ㟁ᴟࡀࡁࡕࢇ᥋ ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒⏝࠸ࡽࢀࡿ㟁ィࡣࠊᗈ í6 ࠸ࢲࢼ࣑ࢵࢡࣞࣥࢪࢆᣢࡕࠊ10 ࡽ 10 í14 ⥆ࡉࢀ࡚࠸࡞࠸ሙྜ࡛ࡶࠊ㟁Ⲵࡣ ᐃࡉࢀ࡚ࡋࡲ࠺ࠋ C ࡢ⠊ くⓗ࡞㸦ᶵᲔⓗ࡞㸧ࢸࢫࢺࡣูࠊ㐃⥆ᛶࢆ ᅖࡢ㟁Ⲵࢆ ᐃࡍࡿࡇࡀ࡛ࡁࡿࠋࢫ࢟ࣕࢽࣥࢢࢆ ಖドࡍࡿࡓࡵࡢࢸࢫࢺࡀ࠶ࡿࠋࡶࡋ㟁ィࣂ ⾜࠺๓㟁ィࡢ㞽Ⅼㄪᩚࢆ⾜࠺ࡁ࡛࠶ࡿࠋࡲࡓࠊ ࢫࢆㄪᩚ࡛ࡁࡿሙྜࠊࣅ࣮࣒ࢹ࣮ࢱࡢ ᐃ୰ᴟᛶ ⏝ࡍࡿ๓ ᐃࣞࣥࢪࢆኚ᭦ࡋ࡚ࡶᛂ⟅㸦 ᐃ್㸧 ࢆኚ᭦ࡋࠊ ᐃ್ࡢᴟᛶࡀኚࡍࡿ☜ㄆࡍࡿࠋࡶ ࡢ┤⥺ᛶࡀಖࡓࢀ࡚࠸ࡿࡇࢆ☜ㄆࡋ࡚࠾ࡃࡁ ࡋࠊ㏻ಙࡀ㏵⤯࠼࡚࠸ࡿሙྜࡸࠊධຊ࢜ࣇࢭࢵࢺࡀ ࡛࠶ࡿࠋㄞࡳ್ࡣࠊ᳨ฟჾ㟁ィࡢᛂ⟅ࢆྜᡂࡋ ࠶ࡿሙྜࡣᴟᛶࢆኚ࠼࡚ࡶಙྕࡣኚࡋ࡞࠸ࡓࡵࠊ ࡓ್࡛࠶ࡿࠋ୍⯡ⓗ᳨ฟჾࡢᛂ⟅ࡣ࣐ࢡࣟ⛊ࡔ ᴟᛶࡶಙྕࡢኚࡀ☜ㄆ࡛ࡁࢀࡤࠊ㐃⥆ᛶࡀ ࡀࠊ㟁ィࡢᛂ⟅ࡣ࣑ࣜ⛊࡛࠶ࡿࡓࡵࠊ㟁ィࡢᛂ ಖドࡉࢀࡿࠋ ⟅ࡣࢫ࢟ࣕࢽࣥࢢ࠾࠸࡚ᴟࡵ࡚㔜せ࡞ࡿࠋ 㐃⥆ᛶࡀಖ࡚࡞࠸ࡋ࡚ࠊỈ୰᳨ฟჾࢣ ࣮ࣈࣝࢆධࢀࡓሙྜࡀ⪃࠼ࡽࢀࡿࠋࢥࢿࢡࢱࡸࢲ III.A.3.a. ᐃࡢᴟᛶ 㟁ィࡢධຊᴟᛶࡣ 2 ᴟᆺ 1 ᴟᆺศࡅࡽࢀࡿࠋ ࣉࢱࠊࢣ࣮ࣈࣝ࡞ࡢྲྀࡾᢅ࠸ࡀ㐺ษ࡛࡞࠸ሙྜࠊ ṇࡋ࠸᮲௳ୗ࡛ࡶ㟁㞳⟽ࡢࣂࢫ㟁ᅽࡀࢩ࣮ࣙ 2 ᴟᆺࡣṇ㈇ࡢ୧ᴟᛶ࡛ ᐃࡀྍ⬟ࡔࡀࠊ1 ᴟᆺ ࢺࡋ࡚ࡋࡲ࠺ࡇࡀ࠶ࡿࠋ௨ୗࡢ❶࡛ヲࡋࡃ㏙ࡿ ࡣ∦᪉ࡢᴟᛶࡢ㟁Ⲵࡋ ᐃࡍࡿࡇࡣ࡛ࡁ࡞࠸ࠋ ✵୰࠾ࡼࡧỈ୰࡛ࡢ ᐃࡢẚ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↷ࠋ ࡢၥ㢟ࡣ᫂ࡽ࡞ࡿࠋ III.A.3.b. ධຊ࢜ࣇࢭࢵࢺ㟁ὶ㸦₃ࢀ㟁ὶ㸧 III.A.3.e. ࢤࣥ⮬ືࣞࣥࢪㄪᩚ ᐃ್ࡣ ᐃಙྕࡌࡾࠊ₃ࢀ㟁ὶࡶಙྕ 㟁ィࡣᵝࠎ࡞ࢤࣥࡢ㑅ᢥࡀྍ⬟࡛ࠊ᳨ฟჾࡢ ࡋ࡚ྵࡲࢀ࡚࠸ࡿࠋࡓ࠸࡚࠸ࡢ ᐃ᮲௳࡛࠶ࢀࡤ₃ ឤᗘࡢ㐪࠸ྜࢃࡏ࡚㑅ᢥࡍࡿࡇࡀ࡛ࡁࡿࠋࢤ ࢀ㟁ὶࡣၥ㢟࡞ࡽ࡞࠸ࡀࠊୖグࡢ࠾ࡾࠊឤᗘࡢ ࣥࡣ⮬ືࡶࡋࡃࡣᡭື࡛タᐃࡍࡿࡇࡀ࡛ࡁࠊᡭື ప࠸ᑠయ✚ࡢ⥺㔞ィࡼࡿࣉࣟࣇࣝ ᐃࡢ㝿 ࡛ࢤࣥࢆタᐃࡍࡿሙྜࠊᇶ‽Ⅼ࡛ࣇ࣮ࣝࢻ⥺㔞 ࡣၥ㢟࡞ࡿሙྜࡀ࠶ࡿࠋ ィࣜࣇࣞࣥࢫ⥺㔞ィࡢឤᗘࡀࡰ➼ࡋࡃ࡞ࡿ ࡼ࠺タᐃࡍࡿࡁ࡛࠶ࡿࠋ III.A.3.c. ධຊ࢜ࣇࢭࢵࢺ㟁ᅽ 㟁ィࡶࡲࡓࠊ㌿ධຊ㠀㌿ධຊࡢ㛫ධ ຊ࢜ࣇࢭࢵࢺ㟁ᅽࢆ⏕ࡌࡿࠋ⌮ㄽⓗࡣࡘࡢධຊ III.A.3.f. ಙྕࡢ㣬 ึᮇタィ࡛ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒⤌ࡳ㎸ࡲࢀ 31 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 ࡚࠸࡞࠸᳨ฟჾࢆ⏝ࡍࡿሙྜࠊ㟁ィࡢ ᐃࣞࣥ ୖࢱࣥࢡࢆ⨨࠸࡚ࡣ࠸ࡅ࡞࠸ࠋ୍⯡ⓗࡣࠊỈࢆ ࢪࡽ ᐃ್ࡀእࢀ࡚ࡋࡲ࠺ሙྜࡀ࠶ࡿࠋᑠయ✚ࡢ ㈓ࡵࡓࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢ㔜ࡉࡣ 280 kg ㏆ࡃ 㟁㞳⟽ࡢሙྜࠊឤᗘࡣ 0.5 nC/Gy ࡛࠶ࡿࠊࢲ࣮࢜ ࡞ࡾࠊᐷྎࡢ㔜㔞ไ㝈ࢆ㉸࠼࡚ࡋࡲ࠺ࠋࡑࡢࡓࡵࠊ ࢻ࡛ࡣ 50 nC/Gy ࡑࢀ௨ୖࡢሙྜࡶ࠶ࡾࠊឤᗘᕪ ࢇࡢ〇㐀ᴗ⪅ࡣࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࢆ㈓Ỉ ࡀ 100 ಸ㏆ࡃ࡞ࡿࠋࡶࡋࠊᑠయ✚ࡢ㟁㞳⟽ࡢ ᐃ ࢱࣥࢡࡢୖಖᣢ࡛ࡁࡿࡼ࠺࡞ࢩࢫࢸ࣒ࠊࡶࡋࡃ ࣞࣥࢪ࡛ࢲ࣮࢜ࢻ᳨ฟჾࢆ⏝ࡍࡿࠊಙྕࡣᐜ ࡣࡑࢀࡽࢆูࠎࡋ࡚ᑓ⏝ࡢ㡹࡞ಖᣢල࡛ᨭ࠼ ᫆㣬ࡋ࡚ࡋࡲ࠺ࠋಙྕࡢ㣬≧ἣࡽࠊࢫ࢟ࣕ ࡿࡼ࠺࡞㡹࡞ࢩࢫࢸ࣒ࢆᥦ౪ࡋ࡚࠸ࡿࠋࢫ࢟ࣕࢽ ࣥࡢ␗ᖖࢆศᯒࡍࡁ࡛࠶ࡿࠋࡇࡢࡼ࠺࡞≧ἣࡣࠊ ࣥࢢࢱࣥࢡࡣࠊ᳨ฟჾࢆືࡍ㝿㥑ື㒊ࡢືࡁࡀ ࢙࢘ࢵࢪࣉࣟࣇࣝࡢࡼ࠺ಙྕࡀࡁࡃኚ ᭱ᑠ࡞ࡿࡼ࠺タ⨨ࡍࡁ࡛࠶ࡿࠋ࠼ࡤࠊከࡃ ࡍࡿ ᐃ࡛Ⓨ⏕ࡍࡿࠋ ࡢ 3D ࢩࢫࢸ࣒࡛ࡣ x ᪉ྥࡢࢫ࢟ࣕࣥࡣ᳨ฟჾࡢࡳ ࡀ㥑ື࣮࣒ἢࡗ࡚㥑ືࡍࡿࡀࠊy ᪉ྥࡢࢫ࢟ࣕ III.A.3.g. ಙྕࣀࢬẚ ࣥࡢ㝿ࡣ࣮࣒యࢆືࡍᚲせࡀ࠶ࡿࠋx ᪉ྥࡢ 㣬ࡣ㏫ࠊಙྕ㊊ࡢࡓࡵࣀࢬࡀಙྕࡼ ࢫ࡛࢟ࣕࣥࡣ㥑ື㒊ศࡀᑡ࡞࠸ࡓࡵࠊỈ㠃ࡀᦂࢀࡿ ࡾࡁࡃ࡞ࡿሙྜࠊಙྕࣀࢬ㸦SN㸧ẚࡣᑠࡉࡃ࡞ ྜࡀᑡ࡞ࡃࠊࡼࡾࡁࢀ࠸࡞ࢹ࣮ࢱ㞟ࡀྍ⬟࡞ ࡿࠋ㐺ษ࡞᳨ฟჾࢤࣥࠊపࣀࢬࡢ㧗ရ㉁ࢣ࣮ ࡿࠋࡲࡓࠊ⒪ィ⏬⨨ෆ࡛ࡢᗙᶆࢫ࢟ࣕࣥࡢ㝿 ࣈࣝࢆ㑅ࡧࠊ㧗࠸ SN ẚࢆಖࡘࡁ࡛࠶ࡿࠋගᏊ⥺ ࡢᗙᶆࡀ୍⮴ࡍࡿࡼ࠺ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࢆタ ࡢ༙ᙳ㒊ศࡢ ᐃࡸࠊ㟁Ꮚ⥺ࡢไືᨺᑕࡼࡿࢸ࣮ ⨨ࡍࡿࡁ࡛࠶ࡿࠋࢥ࣑ࢵࢩࣙࢽࣥࢢ୰࡛ࡢᗙᶆࡢ ࣝ㒊ศࡢ ᐃࡢ㝿ࠊࢫ࢟ࣕࣥࢹ࣮ࢱࡀࡽ࡛࡞ ࣛ࣋ࣜࣥࢢࡢኚ᭦ࡣࠊవィ࡞㛫ࢆ⏕ࡌࡉࡏࠊΰ ࠸ሙྜࡣ SN ẚࢆ☜ㄆࡍࡿࡁ࡛࠶ࡿࠋࢫ࢟ࣕࢽࣥ ࢆᣍࡃࡓࡵ⾜࠺ࡁ࡛ࡣ࡞࠸ࠋ ࢢࡢ㝿ࡣ SN ẚࢆᑡ࡞ࡃࡶ 100 ௨ୖ⥔ᣢࡍࡿ ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢཎⅬ㸦0,0,0㸧ࡣ⨨ࡢ ࡇࡀⰋ࠸ᇶ‽࡞ࡿࠋ ࢯࢭࣥࢱ㏆࡙ࡅࡿࡁ࡛ࠊ㞳ࢀ࡚࠸ࡿࡁ࡞↷ ᑕ㔝ࢆ ᐃࡍࡿ㝿ၥ㢟࡞ࡿࡇࡀ࠶ࡿࠋx ㍈ࡣ III.A.3.h. ᛂ⟅㛫 ࣮ࣞࢨࡢ cross-plane㸦left-right ᪉ྥ㸧ྜࢃࡏࠊy 㟁ィࡢᛂ⟅㛫ࡣࠊಙྕࡢኚࡢ᳨ฟ㏿ᗘࢆỴ ㍈ࡣ in-plane㸦gun-target ᪉ྥ㸧ྜࢃࡏࡿࡢࡀⰋ࠸ ᐃࡍࡿࠋࣅ࣮࣒ࡢ㎶⦕㒊ศ࡛ࢫ࢟ࣕࣥ㏿ᗘࡀ㏿࠸ሙ ᪉ἲ࡛࠶ࡿࠋx ࣉࣟࣇࣝ y ࣉࣟࣇࣝࡢᕪ ྜࠊ᳨ฟჾࡢಙྕࡣᛴ㏿ኚࡍࡿࠋࡶࡋᛂ⟅㛫 ࡣ 1%⛬ᗘぢ㎸ࡲࢀࠊࡓ࠸࡚࠸ࡢ⨨ࡣࡇࡢ࠶ࡓࡾ ࡀ㛗ࡃࢫ࢟ࣕࣥ㏿ᗘࡀ㏿࠸ሙྜࠊ༙ᙳ㒊ศࡢᙧ≧ࡣ ࡀチᐜ್࡞ࡿࠋSiemens ♫ࡢ⒪⨨ࡢࡼ࠺ࣅ ᗈࡀࡿࠋࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡼࡾ␗࡞ࡿࣉࣟ ࣮࣒ࢫࢸࣜࣥࢢࡀ in-plane ᪉ྥࡢࡳࡢሙྜࡣࠊx ࣮ࢳከᵝ࡞ᛂ⟅㛫ࢆᣢࡘࡓࡵࠊᩘ್ࢆ୍⯡ࡋ ᪉ྥࡢࣉࣟࣇࣝࡣࡼࡾࡽ࡞ࡾࠊၥ㢟ࡣᑡ ࡚ᥦ౪ࡍࡿࡇࡣᅔ㞴࡛࠶ࡿࠋ⌧ᅾࡢࢫ࢟ࣕࢽࣥࢢ ࡞ࡃ࡞ࡿࠋࡲࡓࠊྍ⬟࡛࠶ࢀࡤ〇㐀ᴗ⪅ࡀᥦ౪ࡍࡿ ࢩࢫࢸ࣒ࡢᆺⓗ࡞ᛂ⟅㛫ࡣ 10 ms ௨ୗ࡛ࠊࢫ࢟ ᐃ㍈ࡢㄪᩚ⨨ࢆ⏝ࡍࡁ࡛࠶ࡿࠋከࡃࡢࢫ࢟ ࣕࣥ㏿ᗘࡣ 1 ࡽ 500 mm/s ࡛⛣ື࡛ࡁࡿࡇࡽࠊ ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣ xࠊyࠊz ࡢࣛ࣋ࣜࣥࢢࢩࢫࢸ ᭱㧗 100 mm/s ࡲ࡛ࡢࢫ࢟ࣕࣥ㏿ᗘࡍࢀࡤၥ㢟࡞ ࣒ࡀ⤌ࡳ㎸ࡲࢀ࡚࠸ࡿࠋࣛ࣋ࣜࣥࢢࡣ TPS ୍⮴ࡉ ࠸࡛࠶ࢁ࠺ࠋ ࡏࡿࡇࡀᮃࡲࡋ࠸ࠋ III.B. ࢫ࢟ࣕࢽࣥࢢ⏝Ỉࢱࣥࢡ III.B.2. ࢫ࢟ࣕࢼࡢ㥑ື III.B.1. ࣏ࢪࢩࣙࢽࣥࢢࣛ࣋ࣜࣥࢢ ᳨ฟჾࢆࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢᅄ㝮ືࡋࠊ ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢ㐺ษ࡞タ⨨ࣛ࣋ࣜࣥࢢ ࡢⅬ࡛ࡶỈ㠃᳨ฟჾࡢỈᖹࣞ࣋ࣝࡀ୍⮴ࡋ࡚࠸ 㸦㍈ྡࡢタᐃ㸧ࡣࠊ ᐃࢹ࣮ࢱࡢရ㉁ಖドࠊࢫ࢟ ࡿࡇࢆ☜ㄆࡍࡿᚲせࡀ࠶ࡿࠋࡶࡋࠊ᳨ฟჾࡢỈᖹ ࣕࣥࢹ࣮ࢱࡢ࢚࣮ࣛࡢཎᅉࢆ᳨ฟࡍࡿࡓࡵࡣ ࣞ࣋ࣝࢆ☜ㄆࡍࡿࡓࡵࡢ࢟ࣕࢵࣉᆺࡢᑓ⏝ჾලࢆ ྍḞ࡛࠶ࡿࠋࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢ㔜ࡳ࡛⒪ᐷྎ ᡤ᭷ࡋ࡚࠸ࡿࡢ࡛࠶ࢀࡤ⏝ࡍࡁ࡛࠶ࡿࠋࡲࡓࠊ ࡢᨭᣢᶵᵓࡣ⡆༢ቯࢀ࡚ࡋࡲ࠺ࡓࡵࠊỴࡋ࡚ᐷྎ ᳨ฟჾୖࡢ࣐࣮ࢡࡸࡑࡢࡢ☜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) ࡿࡇ࡛ࡶỈ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 ☜ㄆࡍࡿࡇࡀ࡛ࡁࡿࠋ x 㔜㗽ἢࡗ࡚ᆶ┤᪉ྥ࣮࣒ࢆືࡋࠊṇ☜ ᆶ┤⛣ືࡋ࡚࠸ࡿ☜ㄆࡍࡿࠋ x jaw ࢆ᳨ฟჾࡢഃ㠃࠾ࡼࡧඛ➃ࡽ 1 mm ⛬ᗘ FIG. 6. Sequential appearance of chamber and its reflection in water viewed from tank side. The correct position is when both images form a perfect circle. 㛤ࡁࠊ᳨ฟჾࢆỈ㠃ࡽᆶ┤ỿࡵࠊ↷ᑕ㔝ෆ ࡢࢡࣟࢫ᳨࣊ฟჾࠊ࠾ࡼࡧග↷ᑕ㔝➃᳨ ฟჾࡢ⨨㛵ಀࢆぢࡿࡇ࡛㍈ࢆ☜ㄆࡍࡿࠋࡶ III.B.2.c. 㟁㞳⟽ࡢኚ Ỉ㠃᳨ฟჾࡢ⨨ࢆṇ☜࡞SSDྜࢃࡏࡿࡇ࡛ࠊ ࡋ㍈ࡀࡎࢀ࡚࠸ࢀࡤ᫂ࡽ᳨ฟࡍࡿࡇࡀ࡛ ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢཎⅬࢆタᐃࡍࡿࡇࡀ࡛ ࡁࡿࠋ ࡁࡿࠋ࠸ࡃࡘࡢ ᐃࣉࣟࢺࢥ࡛ࣝࡣ᳨ฟჾࡢᗄఱ ࡇࢀࡽࡢࢸࢫࢺࡣࠊࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢỈᖹㄪᩚ Ꮫⓗ୰ᚰࡣ ᐃⅬ࡛ࡣ࡞࠸ࡓࡵࠊ ᐃࡢ㝿ࡣᐇຠ୰ ᙳ㡪ࡍࡿࡓࡵࠊỈࡣ‶ᮼࡢ≧ែ࡛⾜࠺ࡁ࡛࠶ࡿࠋ ᚰኚࡍࡿᚲせࡀ࠶ࡿࠋගᏊ㟁Ꮚ࡛ᐇຠ୰ᚰࡣ ␗࡞ࡾࠊࡉࡽࣉࣟࢺࢥࣝࡼࡗ࡚ࡶᐇຠ୰ᚰࡣ␗ III.B.2.b. ࢮࣟⅬࡢ῝ࡉ SSD ࢆタᐃࡍࡿ㝿ࡣࠊ⨨Ỵࡵ࣮ࣞࢨࠊODIࠊ࣓ ࡞ࡿヂ⪅ὀ 2 82,87,88 ࠋ⟄ᙧ㟁㞳⟽ࢆỈࣇࣥࢺ࣒୰࡛ ⏝ࡍࡿሙྜࠊFig. 6 ♧ࡍࡼ࠺ᗄఱᏛⓗ୰ᚰࡣ ࢝ࢽ࣏࢝ࣝࣥࢱ࡞ࡽࠊᑡ࡞ࡃࡶࡘࡢ᪉ἲ ṇ☜タ⨨ࡍࡿࡇࡀ࡛ࡁࠊ㟁㞳⟽⥺㔞ィࡢࢩࣇࢺ ࡼࡾ☜ㄆࡍࡁ࡛࠶ࡿࠋ࣮ࣞࢨࡀ㊥㞳ィࡋ࡚ᶵ ࡣࡇࡢึᮇ⨨ࡽ⾜࠺ࡇࡀ࡛ࡁࡿࠋከࡃࡢࢫ࢟ ⬟ࡍࡿࡢ࡛࠶ࢀࡤ࡚ࡶ⡆౽࡞᪉ἲ࡛࠶ࡿࡀࠊࡇࡢ ࣕࢽࣥࢢࢩࢫࢸ࣒࡛ࡣࡇࡢ࢜ࣇࢭࢵࢺࢆࢯࣇࢺ࢘ ᪉ἲࡢሙྜ࣮ࣞࢨࡢ⨨⢭ᗘࢆ☜ㄆࡋ࡚࠾ࡃᚲせ ࢙ୖ࡛ࠊࡶࡋࡃࡣᡭື࡛タᐃ࡛ࡁࡿࠋࡶࡋࢫ࢟ࣕ ࡀ࠶ࡿࠋỈ㠃ࢆ࣮ࣞࢨ࠾ࡼࡧ࣓࢝ࢽ࣏࢝ࣝࣥࢱࡢ ࢽࣥࢢࢩࢫࢸ࣒ࡢࢯࣇࢺ࢙࡛࢘࢜ࣇࢭࢵࢺࢆ⿵ ⨨ṇ☜୍⮴ࡉࡏࠊ᳨ฟჾࡢ୰ᚰࢆỈ㠃ࢭࢵ ṇࡍࡿࠊ ᐃࡋࡓ್㛵㐃ࡍࡿ῝ࡉࡣᩚᩘ࡛ࡣ࡞ ࢺࡍࡿࠋ⟄ᙧࡢ㟁㞳⟽ࡢሙྜࢭࢵࢺࡣᐜ࡛᫆ࠊୗ ࡃ࡞ࡿࠋከࡃࡢ㟁㞳⟽ࡢ࢜ࣇࢭࢵࢺࡣ 1.5 mmࡽ ࡽぢ࡚Ỉ㠃ᑕࡋࡓ㟁㞳⟽ࡢᙧ≧࡛Ỵᐃ࡛ࡁ 2.0 mmࡢ㛫࡛ࠊࢮࣟⅬࡽୗഃࢩࣇࢺࡉࡏࡿࠋࡇ ࡿࠋFig. 6 ࡢࡼ࠺ࠊ 㸦Ỉ୰ࡢ㸧㟁㞳⟽Ỉ㠃ᑕ ࡢ᪉ἲࡼࡾࠊṇ☜࡞῝ࡉ࡛ࡢ ᐃࡀྍ⬟࡞ࡿࠋ ࡋࡓീࡀࡁࢀ࠸࡞ࢆᥥ࠸࡚࠸ࢀࡤࠊ㟁㞳⟽୰ᚰ Ỉ㠃ࡀṇ☜୍⮴ࡋ࡚࠸ࡿࠋࡇࡢ࣏ࢪࢩࣙࣥࢆࢮࣟ III.B.3. ࢫ࢟ࣕࢽࣥࢢࡢ᪉ྥ Ⅼࡋࠊࢫ࢟ࣕࣥ⏝ࡍࡿ PC ᗙᶆࢆࢭࢵࢺࡍ ከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣࢫ࢟ࣕࢽࣥࢢࢱ ࡁ࡛࠶ࡿࠋỈࡢⓎࡼࡗ࡚Ỉ㠃ࡣኚࡍࡿྍ⬟ ࣥࢡ࢞ࣥࢺࣜࡢ㍈ࡢ㛵ಀࢆᐃ⩏ࡍࡿࡇࡀ࡛ࡁ ᛶࡀ࠶ࡿࡓࡵࠊ ᐃ᪥ࡢ᭱ึࠊࡑࡢᚋᑡ࡞ࡃࡶ ࡿࠋ୍⯡ⓗࡣ y ㍈ࡣ gun-target ᪉ྥ࡛ࠊx ㍈ࡣ 6 㛫࠾ࡁỈ㠃ࢆ☜ㄆࡍࡁ࡛࠶ࡿࠋ࠶ࡿࢫ࢟ࣕ cross-plane ᪉ྥ࡛࠶ࡿࡀࠊࡇࡢ⨨࡙ࡅࢫ࢟ࣕࣥ ࢽࣥࢢࢩࢫࢸ࣒ࡣࢫ࢟ࣕࣥ㸦᳨ฟჾ࠾ࡼࡧ㥑ື ᪉ྥࡀṇࡋ࠸ࡇࢆ☜ㄆࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋタ⨨ ࣮࣒ࡀ㸧ỈỿࢇࡔศỈ㠃ࢆኚ᭦ࡍࡿ࣮ࣔࢱࢆᣢ ࡍࡿ⨨㛵ಀࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ᐃ⩏ࡍࡿ ࡘࠋࢯࣇࢺ࢙࢘ࡣỈࡢኚᇶ࡙࠸࡚῝ࡉࢆኚ᭦ ⨨㛵ಀࡀṇࡋࡃ࡞࠸ሙྜࠊTPS ධຊࡍࡿࢹ࣮ࢱ ࡍࡿࡀࠊࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡀࡁ࠸ሙྜࡣࡇࡢㄗ ࢆㄗࡿྍ⬟ᛶࡀ࠶ࡿࠋ࠼ࡤࠊTPS 45 ᗘࡢ࢙࢘ ᕪࡣᑠࡉ࠸ࠋࡇࡢࡼ࠺࡞ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࢆ ⏝ࡍࡿሙྜࡣࠊ᧯సࡣ༑ศẼࢆࡘࡅࡿࡁ࡛ࠊ ⏝๓ࢯࣇࢺ࢙࢘ࡼࡿ⿵ṇࡀṇ☜☜ࡵ࡚ ࠾ࡃࡁ࡛࠶ࡿࠋ ヂ⪅ὀ2 ᶆ‽ 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⥺ࡢࣉࣟࣇࣝࡀ㐺ษ࡞ᙧ≧࡛࡞࠸ ሙྜࡣࠊ࣮࣒ࡸỈᵴࡀഴ࠸࡚࠸ࡿࡇࡀ⪃࠼ࡽࢀࠊ ㄪᩚࢆ⾜࠺ࡁ࡛࠶ࡿࠋ III.B.3.b. ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡࡢഴࡁ FIG. 7. (a) Beam profiles of a 6 MV beam at different depth with ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢỈᖹᗘࡢㄪᩚࡣࢫ࢟ࣕ scanning arm tilt for a 4×4 cm2 field, (b) electron beam profiles at ࢽࣥࢢࢱࣥࢡయ࡛⾜࠺ࠊ࣮࣒ࡔࡅ࡛⾜࠺ࡢ depth of 80% depth dose for 20×20 cm2 cone with gantry tile. Arrows 2 ㏻ࡾ࠶ࡿࠋගᏊ⥺ࡢ ᐃ࠾࠸࡚ࠊ࣮࣒ࡢഴࡁ and circle are shown to represent the impact of arm and gantry tilt. ࡀᑐ⛠ᛶ࠼ࡿᙳ㡪ࡣᑠࡉ࠸ࠋࡋࡋࠊFig. 7(a) ♧ࡍࡼ࠺ࠊ࣮࣒ࡀഴ࠸࡚࠸ࡿሙྜࠊಶࠎࡢࢫ ࢟ࣕࣥࡢ୰ᚰࡣ῝㒊࡞ࡿࡎࢀࡿࠋᑠ↷ᑕ㔝ࡸ ࢵࢪࣉࣟࣇࣝࢆධຊࡍࡿࡁࠊᐇ㝿 ᐃࡋ ࢙࢘ࢵࢪ↷ᑕ㔝࡛ࡇࡢᙳ㡪ࡣ㔜࡛ࠊPDD ࡣ୰ᚰ㍈ ࡓࢹ࣮ࢱࡀ࢙࢘ࢵࢪࡢ㠀໙㓄᪉ྥ࡛࠶ࡿሙྜࡣࠊ῝ ࡽࡎࢀࠊ࢙࢘ࢵࢪࡢཌࡳࡀ␗࡞ࡿ㒊ศࢆ ᐃࡍࡿ ้࡞ࢹ࣮ࢱධຊ࣑ࢫࡘ࡞ࡀࡿࠋ ࡇ࡞ࡿࠋ㟁Ꮚ⥺࡛ࡣࠊFig. 7(b)ࡀ♧ࡍࡼ࠺ࠊ ≉⥺㔞໙㓄ࡀᛴ࡞ప࢚ࢿࣝࢠ࣮ࡢሙྜࡣࠊdmax ௨ III.B.3.a. ࢫ࢟ࣕࣥ㍈ࡢ࣓ࣛࣥࢺ ṇ☜࡞ࢹ࣮ࢱ ᐃࢆ⾜࠺ࡓࡵࡣࠊ࢞ࣥࢺࣜࡢ y 㝆ࡢ῝ࡉ࡛࣮࣒ࡢഴࡁࡼࡿᙳ㡪ࡣ㢧ⴭ⾲ࢀ ࡿࠋ ᪉ྥ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 ࣮ࢡ࣮ࣞࢨࢆྜࢃࡏࡿࠊ᳨ฟჾࡢಖᣢලࢆࣇ cross-plane ࡢࣉࣟࣇࣝࡸ PDD ᙳ㡪ࢆཬࡰࡍࠋ ࣮ࣝࢻࡢ➃ྜࢃࡏࡿࡇ࡛㐩ᡂࡉࢀࡿࠋࡇࢀࡣࡲ ࡇࡢᙳ㡪ࡣᑠࡉ࠸ࡀࠊ῝㒊࡛ࣉࣟࣇࣝࡢ㠀ᑐ⛠ ࡓࠊ㍈ἢࡗ᳨࡚ฟჾࢆᡭື࡛⛣ືࡉࡏࡓࡁࠊ ࡀ⏕ࡌࡿ㸦Fig. 8㸧 ࠋࢫ࢟ࣕࣥ๓࢞ࣥࢺࣜࢆỈᖹ ᳨ฟჾ୰ᚰࡀࢡࣟࢫ࣊ࡢⅬ࡛ࡶ୍⮴ࡍࡿࡇ ࡍࡿࡇࡣྍḞ࡛ࠊcross-plane ᪉ྥࡢ ᐃ࡛㠀ᑐ ࢆಖドࡍࢀࡤ☜ㄆ࡛ࡁࡿࠋ⨨ྜࢃࡏࢆṇ☜⾜ ⛠ࢆ㑊ࡅࡿࡓࡵࠊ࢞ࣥࢺࣜゅᗘࡣ⢭ᐦ࡞Ỉ‽ჾ࡛☜ ࢃ࡞࠸ࠊ ᐃࡋࡓࣉࣟࣇࣝࡢ↷ᑕ㔝ࢧࢬࡣ ㄆࡍࡁ࡛࠶ࡿࠋ ṇ☜࡛ࡣ࡞ࡃ࡞ࡾࠊ࢙࢘ࢵࢪࣉࣟࣇࣝ࡞ࡢࢹ 34 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㥑ືᶵᵓືࡁ ࡍࡿ๓ࡣࠊ๓ ᐃࢸࢫࢺࢆ⾜࠺ࡁ࡛࠶ࡿࠋ III.C.1. 㓄ิᆺ᳨ฟჾࡢ㔜㔞 ࡲࡓࠊ⨨ࡢ⢭ᗘ⟶⌮ࡢࡓࡵࡢẖᖺࡢᰯṇࢆ⾜࠺๓ Ỉࣇࣥࢺ࣒ࢩࢫࢸ࣒࠾࠸࡚ࠊ㸦᳨ฟჾࡢ㸧ಖ ࡶࠊ๓ࡢ ᐃࢸࢫࢺࡣྍḞ࡛࠶ࡿࠋࡍ࡚ࡢ ᣢලࢫ࢟ࣕࣥᶵᵓࡣẚ㍑ⓗᑠࡉࡃ㍍࠸᳨ฟჾࢆ ࢣ࣮ࣈࣝࢆ᥋⥆ࡋ࡚ࢫ࢟ࣕࢽࣥࢢࢱࣥࢡỈࢆ㈓ ᐃࡋ࡚సࡽࢀ࡚࠸ࡿࠋᗄࡘࡢ㓄ิᆺࡢ᳨ฟჾࡣ ࡵ࡞࠸≧ែ࡛ࠊࣇ࣮ࣝࢻ⥺㔞ィࢆࢯࢭࣥࢱୖ ಖᣢලࡢไ㝈ࢆ㉸࠼ࡓ㔜ࡉ࡛࠶ࡿࠋࢫ࢟ࣕࢽࣥࢢࢩ タ⨨ࡋࠊࣜࣇࣞࣥࢫ⥺㔞ィࡣࣇ࣮ࣝࢻ⥺㔞ィ ࢫࢸ࣒࡛㓄ิᆺ᳨ฟჾࢆ⏝ࡍࡿ๓ࠊ〇㐀ᴗ⪅ ࡢࢫ࢟ࣕࣥ⠊ᅖୖධࡽ࡞࠸ࡼ࠺㐺ษタ⨨ࡍ ☜ㄆࢆࡽࡡࡤ࡞ࡽ࡞࠸ࠋ㓄ิᆺ᳨ฟჾࡢ㔜ࡉࢧ ࡿࠋࢫ࢟ࣕࣥ⏝ࡢ᳨ฟჾࣅࣝࢻࢵࣉ࢟ࣕࢵࣉࢆ ࢬࡢᙳ㡪ࢆ⪃៖ࡍࡿࡓࡵࠊࢹ࣮ࢱ㞟ࡢ๓ࢫ࢟ ╔ࡋࠊ㟁ィᚲせ࡞ㄪᩚࢆ⾜࠸ࠊ20 × 20 cm2 ࡢ ࣮࣒ࣕࣥࡢືࡁࢆ☜ㄆࡍࡿࡁ࡛࠶ࡿࠋ ↷ᑕ㔝࡛ࠊ㸫20 ࡽ 20 cm ࡲ࡛✵୰࡛ࢫ࢟ࣕࣥࢆ⾜ ࠺ࠋࢫ࢟ࣕࢼࡼࡗ࡚ࡣࠊࣜࣇࣞࣥࢫ⥺㔞ィࡽ III.C.2. ㏿ᗘ⨨ࡢ⢭ᗘ ᳨ฟჾࡢಙྕࡢᙉᗘࠊឤᗘࠊ㟁ィࡢ㞟㛫ࠊ ಙྕࡀ࡞࠸ሙྜࠊࢫ࢟ࣕࣥࡀṆࡍࡿࡓࡵࢻࣛࣛ ࣥࢆ⾜࠼࡞࠸ࢱࣉࡶ࠶ࡿࠋ ⨨⢭ᗘࡼࡗ࡚ࡣ᳨ฟჾࡢ⛣ື㏿ᗘࢫ࢟ࣕࢽ ᐃࢆ⧞ࡾ㏉ࡋ⾜࠸ࠊ᳨ฟჾࡀࢡࣟࢫ࣊୰ᚰ ࣥࢢࢩࢫࢸ࣒ࡀᑐᛂ࡛ࡁ࡞࠸ሙྜࡀ࠶ࡿࠋࡇࢀࡽࢆ 㐩ࡋࡓࡽ↷ᑕࢆ୰᩿ࡍࡿࠋࢫ࢟ࣕࣥࢹ࣮ࢱࢆಖᏑࡋ ☜ㄆࡍࡿࡓࡵࠊ᭱㧗㏿ᗘ᭱ప㏿ᗘ࠾࠸࡚ࠊ20 ࡚ࠊࢫ࢟ࣕࢼࡢࢯࣇࢺ࢙࢘ࡸࢫࣉࣞࢵࢻࢩ࣮ࢺࢆ cm ࡢ↷ᑕ㔝࡛ 40 cm ࡢ⠊ᅖࢆࢫ࢟ࣕࣥࡋࠊࡘࡢ ⏝ࡋ࡚ࠊḟࡢ㡯┠ࢆゎᯒࠊ᳨ウࢆ⾜࠺ࠋ ࣉࣟࣇࣝࢆẚ㍑ࡍࡁ࡛࠶ࡿࠋࡶࡋ┦ᑐⓗ࡞ᙧ x ࣀࢬ㸸ࣉࣟࣇࣝࡢᖹᆠ࡞㒊ศࡢᶆ‽೫ᕪ ≧ࡣ୍⮴ࡋ࡚࠸࡚ࠊ⨨ࡀࢩࣇࢺࡋ࡚࠸ࢀࡤࠊࢫ࢟ ࢆồࡵࡿࠋࡇࢀࡣ↷ᑕࡢࣀࢬࡢᶆ‽೫ᕪࢆ ࣕࣥ㏿ᗘ㝈⏺ࡀ࠶ࡿࡇࡀ☜ㄆ࡛ࡁࡿࠋ ♧ࡋ࡚࠸ࡿࠋ x III.C.3. ࣄࢫࢸࣜࢩࢫ ືಀᩘ㸧ࡢィ⟬ࢆ⾜࠺ࠋࡇࡢ್ࡣ SN ẚ㏆࠸ ࢫ࢟ࣕࢼࡢ⨨ࡢ࢚ࣥࢥ࣮ࢹࣥࢢ࠾࠸࡚ࣄ ࢫࢸࣜࢩࢫࡀ㉳ࡁ࡚࠸࡞࠸☜ㄆࡍࡁ࡛࠶ࡿࠋࣄ SN ẚ㸸ྠࡌ㡿ᇦ࡛ࠊᶆ‽೫ᕪᖹᆒ್ࡢẚ㸦ኚ ್࡞ࡿࠋ x ᐃᩘ㸸↷ᑕࢆṆࡵࡓⅬࡽ᳨ฟჾࡢಙྕࡀ ࢫࢸࣜࢩࢫ⌧㇟ࡣ୍⯡ⓗᪧᆺࡢࢫ࢟ࣕࢽࣥࢢࢩ ࡞ࡃ࡞ࡿࡲ࡛ࡢ㛫ࢆ ᐃࡍࡿࠋࡇࢀࡣࠊ᳨ฟ ࢫࢸ࣒࡛ၥ㢟࡞ࡾࠊࡇࡢ⌧㇟ࡣྠࡌ↷ᑕ㔝࡛ࠊ୰ ჾṧࡿ㟁Ⲵࡶྵࡵࡓࠊᐃᩘࡶࡋࡃࡣᛂ⟅ ⛬ᗘࡢࢫࣆ࣮ࢻ࡛ ࡋ࡚ࢫ࢟ࣕࣥࢆ⾜࠺ࡇ࡛ 㛫㛵ಀࡋ࡚࠸ࡿࠋ ☜ㄆ࡛ࡁࡿࠋࡶࡋࠊࡘࡢࣉࣟࣇࣝࡀ୍ x ₃ࢀ㟁ὶ㸸↷ᑕࢆ⾜ࡗ࡚࠸࡞࠸ࡁࡢ್ࡀⴠࡕ ⮴ࡋ࡚࠸࡞࠸ሙྜࠊࢫ࢟ࣕࣥࡢືసࣄࢫࢸࣜࢩࢫ ╔࠸࡚ᖹᆠ࡞ࡗࡓ㡿ᇦࡢࠊᖹᆒ್ᶆ‽೫ᕪ ࡀ㉳ࡁ࡚࠸ࡿࡇ࡞ࡿࠋࡇࡢࡼ࠺࡞⌧㇟ࡀⓎ⏕ࡋ ࢆồࡵࡿࠋ ࡓሙྜࡣ〇㐀ᴗ⪅ಟ⌮ࢆ౫㢗ࡋࠊࢫ࢟ࣕࢽࣥࢢ x ᐃ⏝ࡍࡁ࡛ࡣ࡞࠸ࠋ 㟁ィ࢜ࣇࢭࢵࢺ㸸ࡶࡋࠊ㟁ィࢤࣥࡢ⮬ ືㄪᩚᶵ⬟ࡀ࡞࠸ࡢ࡛࠶ࢀࡤࠊ↷ᑕࢆ⾜ࡗ࡚࠸ ࡞࠸㒊ศࡢᶆ‽೫ᕪࠊᖹᆠ↷ᑕࡉࢀ࡚࠸ࡿ III.C.4. ⭉㣗㸦ࡉࡧ㸧 㒊ศࡢᶆ‽೫ᕪࡣࡰྠ➼࡞ࡿࡁ࡛࠶ࡿࠋ Ỉࡢῧຍ≀ࡸಖᏑ᪉ἲ࡞ࡘ࠸࡚ࡣᴗ⪅ࡢ ↷ᑕࡋ࡚࠸࡞࠸ሙྜࡢ್ࡢᖹᆒ್ࡣ㟁ィࡢ࢜ ᥦᚑ࠺ࡁ࡛࠶ࡿࠋ㛗ᮇࢃࡓࡾ⏝ࡋ࡞࠸ሙ ࣇࢭࢵࢺ࡛ࠊྠࡌࢤࣥ࠾ࡅࡿ ᐃ࡛ࡣࡍ ྜࠊ≉᪥ࢆࡲࡓࡄࡼ࠺࡞ሙྜࡣࠊࢫ࢟ࣕࣥᶵᵓࢆ ࡚ࡢࢹ࣮ࢱࡽῶ⟬ࡍࡁ࡛࠶ࡿࠋ Ỉᾐࡋ࡚࠾ࡃࡁ࡛ࡣ࡞࠸ࠋ x 㸦ಙྕࡀ㸧㈇ ᴟᛶ㸸ࡶࡋ㟁ィࡀ 2 ᴟ࡛࠶ࢀࡤࠊ ࡢ್ࢆࡿࡇࡶ࠶ࡾࠊᖹᆒ್ࡀ㈇࡞ࡿࡇ III.D. ᐃ๓ࡢヨ㦂 ࡶ࠶ࡿࠋ 㸦࢜ࣇࢭࢵࢺࢆᕪࡋᘬࡃሙྜ࡞㸧㈇ III.D.1. ࢻࣛࣛࣥ ࡢᖹᆒ್ࢆῶ⟬ࡍࡿሙྜࡣࠊ⤖ᯝࡋ࡚ṇࡢ್ ᪂ࡋ࠸ࢫ࢟ࣕࢼࢆ⏝ࡋ࡚ࣅ࣮࣒ࢹ࣮ࢱࢆ ᐃ ࢆຍ⟬ࡍࡿࡇ࡞ࡿࡢ࡛ࠊṇ㈇ࡢ➢ྕࡣṧࡋ 35 医学物理 第 33 巻 第 1 号 x III. スキャニングシステムのセットアップ ࡚࠾ࡃࡁ࡛࠶ࡿࠋ ࡀ᭷ព࡛࠶ࡿࠊࣉࣟࣇࣝࡢࢸ࣮ࣝ㒊ศࡢ ᐃ ↓ຠ࡞್㸸↷ᑕࢆ⾜ࡗ࡚࠸࡞࠸ࡢ್㸦ࣂࢵࢡ ್ࢆẚ㍑ࡍࡿࡇ࡛☜ㄆࡋ࡞ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋ ࢢࣛ࢘ࣥࢻ㸧ࡀᖖ 0 ࡛ኚືࡀ࡞࠸ሙྜࠊࢹ࣮ ࢱࡀᙉไⓗ 0 ⿵ṇࡉࢀ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿࠋ ࡇࢀࡼࡾࠊ༙ᙳ㒊ศࡸࢸ࣮ࣝࡢ㒊ศ ᐃㄗ III.D.5. ࢚ࢿࣝࢠ࣮ᛂ⟅ᛶࡢヨ㦂 ࢲ࣮࢜ࢻ᳨ฟჾ࡛ PDD ࢆ ᐃࡍࡿሙྜࠊ࢚ࢿ ࣝࢠ࣮ᛂ⟅ࡣ 6 MV ࡢගᏊ⥺ࡢ↷ᑕ㔝㸦40 × 40 ᕪࡀ㉳ࡁࡿྍ⬟ᛶࡀ࠶ࡿࠋ cm2㸧࠾ࡅࡿࡁ࡞య✚ࡢ㟁㞳⟽࡛ ᐃࡋࡓ PDD III.D.2. ࢛࣮࢘ࢱࣛࣥ ẚ㍑ࡍࡿࡇ࡛ࠊホ౯ࡍࡿࡇࡀ࡛ࡁࡿࠋdmax ௨ ᳨ฟჾࢣ࣮ࣈࣝࡀᾐỈࡋࡓ≧ែ࡛ࠊࢣ࣮ࣈࣝࡢ 㝆ࡢ῝ࡉࡢ PDD ࠾࠸࡚ࠊ㟁㞳⟽⥺㔞ィẚࢲ ࢪࣕࢣࢵࢺࡢடࡸ₃㟁ࡀ㉳ࡁ࡚࠸ࡿሙྜࠊ ᐃᶵ ࣮࢜ࢻ᳨ฟჾࡢ⥺㔞᭤⥺ࡢῶᙅࡍࡿഴࡁࡀᑠࡉ ჾࡢᅇ㊰ࡢࣃ࣓࣮ࣛࢱࡀኚࡋࠊ ᐃ⤖ᯝࡶኚࡍ ࠸ሙྜࠊࡇࢀࡣ࢚ࢿࣝࢠ࣮ᛂ⟅ࡢ㐪࠸ࢆ♧ࡋ࡚࠸ࡿࠋ ࡿྍ⬟ᛶࡀ࠶ࡿࠋࡶࡋࢥࢿࢡࢱࡀ㜵ᾐᆺ࡛࡞࠸ࡢ࡛ ࡇࡇ࡛⏝ࡍࡿࡁ࠸ࢧࢬࡢ㟁㞳⟽⥺㔞ィ㸦࠼ ࠶ࢀࡤࠊỈỿࡵ࡚ࡣ࡞ࡽ࡞࠸ࠋࢫ࢟ࣕࢽࣥࢢࢱࣥ ࡤ 0.6 cm3㸧ࡣࠊࡢࡍ࡚ࡢヨ㦂ྜ᱁ࡋ࡚࠾ࡾࠊ ࢡỈࢆ㈓ࡵࠊ᳨ฟჾࢣ࣮ࣈࣝࢆỈỿࡵࡓᚋࠊ ࢫࢸ࣒ࡢ₃ࢀ㟁ὶࡢᙳ㡪࡞ࢆཷࡅ࡞࠸ࡇࡀ๓ ☜ㄆࢆ⾜࠺ࡲ࡛ 30 ศࡑࢀ௨ୖ⤒ࡗ࡚ࡽ⾜࠺ ᥦ࡛࠶ࡿࠋ ࡢࡀ᭱㐺࡛࠶ࡿࠋࢻࣛࣛࣥྠࡌࢸࢫࢺࢆ⧞ࡾ㏉ ࡋࠊࡑࢀࡽࡢࣃ࣓࣮ࣛࢱࡀࡰ୍⮴ࡋ࡚࠸ࡿࡇࢆ III.E. ࢹ࣮ࢱྲྀᚓ ☜ㄆࡍࡿࠋࣀࢬࡢᶆ‽೫ᕪࡀቑຍࡋࡓሙྜࠊࢫ࢟ ࢹ࣮ࢱ㞟ࡣΰࢆ㑊ࡅࡿࡓࡵࠊ⣔⤫❧࡚࡚⾜ ࣕࣥྍ⬟࡞᭱῝࡛ࡢ ᐃࡀᗘᚲせ࡞ࡿࠋࡇࡢ ࠺ࡁ࡛࠶ࡿࠋከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࠾࠸ ᐃ್ࡢ SN ẚࡣ᭱ࡶపࡃ࡞ࡿࡣࡎ࡛࠶ࡿࡀࠊࡇࡢ ࡚ࢹ࣮ࢱ㞟ࡢᡭ㡰ࢆᩚ࠼ࡿࡇࡣࠊࡢࡕࡢࢹ࣮ࢱ SN ẚࡣ᪤▱ࡢࢩࢫࢸ࣒ࡢឤᗘࡑࢀ௨ୖ࡛࠶ࡿ ゎᯒࡢຠ⋡ࢆᖜྥୖࡉࡏࡿࠋࡲࡓࠊࢹ࣮ࢱࡢ୍ ࡁ࡛࠶ࡿࠋ ㈏ᛶṇ☜ࡉࢆྥୖࡉࡏࡿࡓࡵࠊྠࡌࢭࢵࢺࢵ ࣉ࡛ྲྀᚓ࡛ࡁࡿࢹ࣮ࢱࡣྠ㞟ࡍࡿࡁ࡛࠶ III.D.3. 㣬ヨ㦂 ࡿࠋTable I ࡢࡼ࠺࡞ࢫࣉࣞࢵࢻࢩ࣮ࢺࢆ⏝࠸࡚ ᐃ ୖグࡢࢻࣛࣛࣥྠࡌᡭ㡰࡛ࠊ⥺㔞⋡ࢆ᭱ 2 ୰⛬ᗘタᐃࡋ࡚ 20 × 20 cm ࡢ↷ᑕ㔝ࡢ ᐃࢆ⾜ 㡯┠ࢆᩚ⌮ࡍࡿࡇ࡛ࠊࢹ࣮ࢱ㞟ࢆࡍࡤࡸࡃฎ⌮ ࡛ࡁࡿࠋ ࠸ࠊࣉࣟࣇࣝࡢẚ㍑ࢆ⾜࠺ࠋ III.E.1. ࢫ࢟ࣕࣥࣃ࣓࣮ࣛࢱࡢࣉࣟࢺࢥࣝ III.D.4. 㟁㞳య✚እຠᯝ ࢹ࣮ࢱ㞟ࡣࠊ⏝ࡍࡿࢯࣇࢺ࢙࢘౫Ꮡࡍ ࢫ࢟ࣕࣥ⏝ࡢ㟁㞳⟽⥺㔞ィࡢ㟁㞳య✚ࡣ㠀ᖖ ࡿᗄࡘࡢせ⣲ࡀ࠶ࡿࠋࢹ࣮ࢱࡢ㉁ࡣࠊࢫ࢟ࣕࣥ㏿ ᑠࡉ࠸ࡓࡵࠊࢣ࣮ࣈࣝࡸࢥࢿࢡࢱ࡞ࡢ㟁㞳య✚௨ ᗘࠊ㐜ᘏ㛫ࠊࢧࣥࣉࣜࣥࢢ㛫౫Ꮡࡍࡿࡓࡵࠊ እࡢ㒊ศ㸦Extracameral volume㸧ᩓ⥺ࡸ୍ḟ⥺ ࢯࣇࢺ࢙࢘ࡢ≉ᚩࢆά⏝ࡋ࡚᭱㐺࡞ࢹ࣮ࢱ㞟 ࡀ↷ᑕࡉࢀࡿࠊ㟁㞳ࡀ㉳ࡁ࡚ ᐃಙྕᙳ㡪ࢆཬ ࢆࡍࡁ࡛࠶ࡿࠋSec. I B 4 ࡛㏙ࡓࡼ࠺ࠊࣅ࣮࣒ ࡰࡍ㸦㟁㞳య✚እຠᯝ㸸Extracameral effect㸧 83,84,89 ࠋ ࢥ࣑ࢵࢩࣙࢽࣥࢢࡣከࡃࡢ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⤊ᚋ᳨ฟჾࢆ࣐࢘ࣥࢺࡽእࡋ࡚㟁 ࣥ㛫ࡣῶࡿࡀࠊప࢚ࢿࣝࢠ࣮㟁Ꮚ⥺࡛ࡣࢫ࢟ࣕࣥ ィࡢ㏆ࡃ࠾ࡁࠊ᭱⥺㔞⋡࡛↷ᑕࡋࡓሙྜ↷ᑕ ㏿ᗘࢆୖࡆ࡚ࢧࣥࣉࣜࣥࢢ㛫ࢆῶࡽࡍ᭱㐺࡞ ࢆ⾜ࢃ࡞࠸ሙྜࡢ᳨ฟჾࡢᛂ⟅ࢆグ㘓ࡍࡿࠋ᳨ฟჾ ࢹ࣮ࢱࡣᚓࡽࢀ࡞࠸ࠋࡇࢀࡽࡢヲ⣽ࡣྛࢭࢡࢩࣙࣥ ࡢᛂࡀኚࡋࡓሙྜࠊࡑࢀࡣ Extracameral volume ࡛㏙ࡿࠋ ࡼࡿᙳ㡪࡛࠶ࡿࠋࡇࢀࡣࠊ᳨ฟయ✚ࡀ Extracameral volume ẚᑠࡉ࠸ࡓࡵࡔ⪃࠼ࡽࢀࡿࠋࡇࡢຠᯝ 36 III.E.2. ࢫ࢟ࣕࣥ㏿ᗘ Jpn. J. Med. Phys. Vol. 33 No. 1 (2013) III. スキャニングシステムのセットアップ ࢫ࢟ࣕࣥ㏿ᗘࢆ㏿ࡃࡍࡿࣀࢬࡣቑຍࡋࠊࡲࡓࠊ ࣮࣒ࡢືࡁࡼࡾἼࡀ❧ࡘࡇ࡛ ᐃ್ࡶἼᡴ ࡘࠋࡇࢀࡣࠊప࢚ࢿࣝࢠ࣮㟁Ꮚ⥺࠾࠸࡚ dmax ௨ୖ ࡢ῝ࡉࡢࣉࣟࣇࣝࢆ ᐃࡍࡿ㝿ࡁ࡞ᙳ㡪 ࢆཬࡰࡍࠋ࣮࣒ࡀ㏿ࡃືࡁࡍࡂࡿỈ㠃ࡀἼ❧ࡕ ୖୗࡍࡿࡓࡵࠊ 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ࡢ ᐃࡶ㔜 ࡞ᙳ㡪ࢆ࠼ࡿࠋ㟁㞳య✚ࡀᑠࡉ࡞㟁㞳⟽ࡢሙྜࡣ ಙྕࡀᑠࡉ࠸ࡓࡵࠊࢫ࢟ࣕࣥ㏿ᗘࢆ㐜ࡃࡍࡿࡇ࡛ FIG. 9. Impact of scanning speed on the quality of electron profile. ಙྕ㔞ࢆቑࡸࡋࠊ⤫ィⓗኚືࢆῶࡽࡍᚲせࡀ࠶ࡿࠋ III.E.3. 㐜ᘏ㛫 㐜ᘏ㛫ࡣ㞄ࡾྜ࠺ ᐃⅬ㛫ࢆ⛣ືࡍࡿ㛫 ࢆᣦࡍࠋ㛗࠸㐜ᘏ㛫ࢆࡿࡇ࡛ ᐃ㛫ࡣ㛗ࡃ III.F. ࢹ࣮ࢱࣇࣝ III.F.1. ࢹ࣮ࢱࣇࣝࡢᵓᡂ ࢹ࣮ࢱ᳨⣴ࢆ⡆౽ࡍࡿࡓࡵࠊගᏊ⥺ࡢࢹ࣮ࢱ ࡞ࡿࡀࠊప࢚ࢿࣝࢠ࣮㟁Ꮚ⥺ࡢ ᐃࡢࡼ࠺ᑠࡉ࡞ 㟁Ꮚ⥺ࡢࢹ࣮ࢱࡣ␗࡞ࡿྡ๓ࡢࣇ࢛ࣝࢲศࡅ ࡉࡊἼࡢᙳ㡪ࢆࡁࡃཷࡅࡿሙྜࡣࠊࡑࢀࡽࡢᙳ ࡚ಖᏑࡍࡁ࡛࠶ࡿࠋࡉࡽࠊගᏊ⥺ࡢࣇ࢛ࣝࢲࡢ 㡪ࡢపῶ᭷ຠ࡛࠶ࡿࠋ ୰࡛ࡶ࣮࢜ࣉࣥࡸ࢙࢘ࢵࢪ࡞ࡢྡ๓ࡢࣇ࢛ࣝࢲ ࢆసࡿࡇ࡛ࠊ⣽ศࡍࡿࡇࡀ࡛ࡁࡿࠋඃࢀࡓࣇ III.E.4. ࢧࣥࣉࣜࣥࢢ㛫ಙྕ ࢧࣥࣉࣜࣥࢢ㛫ࡣࠊ᳨ฟჾࡀࢹ࣮ࢱ㞟ࡢࡓ ࡵṆࡋ࡚࠸ࡿ㛫ࢆᣦࡍࠋࢧࣥࣉࣜࣥࢢ㛫ࡣࠊ ࣝࡢᵓᡂࢆ⤌ࡳୖࡆࡿࡇ࡛ࠊከࡃࡢࢹ࣮ࢱࡢ ୰ࡽ≉ᐃࡢࢹ࣮ࢱࢆ᥈ࡋฟࡍసᴗ㛫ࢆᖜ ᢚ࠼ࡿࡇࡀ࡛ࡁࡿࠋ 㟁ィࡢࢤࣥࡸ᳨ฟჾࡢࢧࢬ㸦ಙྕࡢ㔞㸧ࡼ ࡗ࡚ㄪᩚࡍࡿࡁ࡛࠶ࡿࠋࡲࡓࠊࢹ࣮ࢱ㞟ࢆ⾜࠺ III.F.2. ࣇࣝࡢྡ๓ ๓ࠊ ᐃࢆ⾜࠺᭱῝ᗘࡢ༙ᙳ㡿ᇦ࡚ಙྕࡢ㔞 ࢹ࣮ࢱࢆ㞟ࡍࡿ㝿ࠊࡢࡕࡢࢹ࣮ࢱ᳨⣴ࢆ⡆౽ ࢆ☜ㄆࡋࠊ㐺ษ࡞ࢧࣥࣉࣜࣥࢢ㛫ࢆỴᐃࡍࡁ࡛ ࡍࡿࡓࡵࠊࣇࣝྡࡢỴᐃἲࢆ☜❧ࡋ࡚࠾ࡃ ࠶ࡿࠋࡲࡓࠊࡾᙜ࡚ࡽࢀࡓࢥ࣑ࢵࢩࣙࢽࣥࢢ㛫 ࡁ࡛࠶ࡿࠋከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡛ࡣࠊ⮬ ࢆ㉸࠼࡞࠸ࡼ࠺࡞ࢧࣥࣉࣜࣥࢢ㛫ࢆタᐃࡍࡿࡇ ືⓗࣇࣝࡢྡ๓ࡀࡾᙜ࡚ࡽࢀࡿ 8 ᩥᏐ௨ ࡶᚲせ࡛࠶ࡿࠋ ෆࡲ࡛㝈ᐃࡉࢀ࡚࠾ࡾࠊࡇࢀࡽࡣྡ๓ࡢỴᐃἲࢆ 」㞧ࡍࡿࠋࡶࡋࣇࣝྡࡢᩥᏐᩘࡀ 8 ᩥᏐ௨ෆ III.E.5. 㧗࿘Ἴࣀࢬࡢᖸ΅ 㝈ᐃࡉࢀ࡚ࡋࡲ࠺ሙྜࠊΰࡋ࡞࠸ࡼ࠺࡞ྡ๓ࢆ ᐃࢩࢫࢸ࣒యࡢఏᑟᛶ㐽ⶸయ㸦㟁㞳⟽ࡸࢲ ࡘࡅࡿࡇࡸࠊ㔜」ࡋ࡞࠸ྡ๓ࢆࡅࡿࡓࡵࡢᕤኵ ࣮࢜ࢻࡢࢩ࢙ࣝࠊࢣ࣮ࣈࣝࡢࢩ࣮ࣝࢻࠊࢥࢿࢡࢱ ࡀᚲせ࡞ࡿࠋࣇࣝྡࡢỴᐃἲࡢࡋ࡚ࠊ࢚ ࢲࣉࢱࠊ㟁ィࡢࢥࢿࢡࢱࠊ㟁ィࡢ⟂య㸧ࡀṇᖖ ࢿࣝࢠ࣮࣭࣮࢜ࣉࣥࡲࡓࡣ࢙࢘ࢵࢪ࣭ࢫ࢟ࣕࣥ᪉ἲ ࡛࠶ࢀࡤࠊ᳨ฟჾࡢಙྕᑐࡋ࡚㧗࿘Ἴࡼࡿᖸ΅ ࡢࡼ࠺༊ศࡅࡍࡿ㸦㸸6P15WDD㸧 ࠋࡓ࠼ ࡣ࡞࠸ࠋ༢⣧࡞ఏᑟᛶ㐽ⶸయࡢࢸࢫࢺࡣࠊ⇱ࡋࡓ Windows ࡢࣇࣝྡไ㝈ࡢࡳ࡛࠶ࡗࡓࡋ࡚ࡶࠊ 㒊ᒇࡢ୰࡛ࣇࣟ㠐ࢆࡘࡅ࡚ᘬࡁࡎࡾ࡞ࡀࡽṌ ࠕ6 MV open depth dose setࠖࡸࠕ18 MV 15 deg wedge ࡃࠊ ᐃࢩࢫࢸ࣒ࡢୖ࡛ᡭࢆࡿ࡞ࡢ⾜Ⅽࢆ⾜࠸ࠊ 10×10 profilesࠖࡢࡼ࠺ࠊࡢࡕ᳨⣴ࡍࡿ㝿ΰ 㟼㟁ẼࢆⓎ⏕ࡉࡏࡿࡇ࡛⾜࠺ࡇࡀ࡛ࡁࡿࠋࡉࡽ ࡋ࡞࠸ࡼ࠺࡞ࣇࣝྡࡢỴᐃἲࢆ᥇⏝ࡍࡁ࡛ ࠊ㒊ရゐࢀࡓሙྜࡢ ᐃᛂ⟅ࡢኚࢆ☜ㄆࡍࡿ ࠶ࡿࠋ࠸ࡃࡘࡢᪧᘧࡢࢩࢫࢸ࣒࡛ࡣࠊࣇࣝࡣ ࡇ࡛ࠊ᥋⥆ࡢၥ㢟ࢆ᫂ࡽࡍࡿࡇࡀ࡛ࡁࡿࠋ ࢩࣥࢢࣝࣇࣝࡋ࡚ෆ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࠺࡞ሙྜ࡛ࡣࠊࡢࡕ᳨⣴ࡸゎᯒᙺ TPS࡛ࡣSSDࢆ 90 cmࡋ࡚ࢥ࣑ࢵࢩࣙࢽࣥࢢࢆ⾜ ❧ࡘࡼ࠺ࠊಶࠎࡢࢫ࢟ࣕࣥࢹ࣮ࢱࢆಖᏑࡍࡿ㝿 ࠺ࠋࡋࡋࠊTPS࣋ࣥࢲ࣮ࡣ័⩦ⓗSSD=100 cmࢆ ヲ⣽࡞ࢥ࣓ࣥࢺࢆグධࡍࡿࡁ࡛࠶ࡿࠋ ᣦᐃࡍࡿሙྜࡀ࠶ࡿࠋࡉࡽࠊ⌧ᅾࡢ୍㒊ࡢ⥺㔞ᰯ ṇࣉࣟࢺࢥࣝヂ⪅ὀ 3࡛ࡣࠊSSD=100 cmࡢPDDࡀᚲせ IV. ගᏊ⥺ࡢࣅ࣮࣒ࢹ࣮ࢱ ࡛࠶ࡿࠋࡼࡗ࡚ࠊࣅ࣮࣒ࢥ࣑ࢵࢩࣙࢽࣥࢢࡢ 1 ࡘ IV.A. ගᏊ⥺ࢫ࢟ࣕࣥࢹ࣮ࢱ ᐃ ࡋ࡚ࠊᵝࠎ࡞SSD࡛⥺㔞ࢆ☜ㄆࡍࡿࡁ࡛࠶ࡿࠋ ᚲせ࡞ࡿ ᐃ㡯┠ࡣࠊ⥺㔞ィ⟬ࢩࢫࢸ࣒㸦TPSࠊ ௨ୗࠊSSD ࡀኚࡋࡓሙྜ῝㒊⥺㔞ᙳ㡪ࡍ MU ィ⟬ࢩࢫࢸ࣒ࠊ࡞㸧౫Ꮡࡍࡿࠋࡲࡓ≉Ṧ࡞ ࡿᅉᏊࢆ♧ࡍࠋගᏊ⥺ࡢ῝㒊⥺㔞ࡣ SSD ࡢኚࡼ ⒪ἲ࡛ࡣ⒪ィ⏬ࢩࢫࢸ࣒ࡢṇ☜ࡉࢆ☜ㄆࡍࡿ ࡗ࡚ྛᡂศࡀ␗࡞ࡿኚࢆ♧ࡍࡓࡵࠊ༢⣧࡞㊥㞳⿵ 2 ࡓࡵࡢ㏣ຍࢹ࣮ࢱࢆ ᐃࡍࡿᚲせࡀ࠶ࡿ ࠋࡇࢀࡽ ṇ࡛ࡣ༑ศ࡛࠶ࡿࠋࡇࡢࡓࡵࠊᣦᐃࡉࢀࡓ SSD ࡛ ࡚ࡢࢹ࣮ࢱࡣࢫ࢟ࣕࣥ ᐃ㠀ࢫ࢟ࣕࣥ ᐃ㸦࣏ ࡢ ᐃࢆᚲࡎᐇࡋࠊ␗࡞ࡿ SSD ࡛ᚓࡓࢹ࣮ࢱࡣᩚ ࣥࢺ⥺㔞 ᐃ㸧ࡼࡾྲྀᚓࡉࢀࡿࠋࢫ࢟ࣕࣥ ᐃ ྜᛶࢆ☜ㄆࡍࡿࡓࡵࡢ QA ࡋ࡚⨨ࡅࡿࡁ࡛ ࡣࠊ↷ᑕ᮲௳㸦㸸↷ᑕ㔝ࢧࢬࠊSSDࠊ⿵ຓჾල ࠶ࡿࠋ㸸 ࡢ᭷↓ࠊ➼㸧ࢆᅛᐃࡋࡓ≧ែ࡛␗࡞ࡿ⨨ࡢ⥺㔞ࢆ 㐃⥆ⓗ ᐃࡍࡿ᪉ἲ࡛࠶ࡾࠊ῝ࡉ᪉ྥࡸ㍈እ᪉ྥ x ΰධ㟁Ꮚ㸦Electron contamination㸧 㸸⾲㠃⥺㔞 ࡢ⥺㔞ኚࢆ ᐃࡍࡿࠋ୍᪉࡛ࠊ㠀ࢫ࢟ࣕࣥ ᐃࡣ ࣅࣝࢻࢵࣉ㡿ᇦ࡛ࡣΰධ㟁Ꮚࡀ」㞧 ↷ᑕ᮲௳ࢆᵝࠎኚࡉࡏ࡚⥺㔞ࡢኚࢆ ᐃࡍ ᙳ㡪ࡍࡿࠋΰධ㟁Ꮚࡣ↷ᑕ㔝ࢧࢬࠊගᏊ࢚ ࡿ᪉ἲ࡛ࠊ㏻ᖖࡣ⥺㔞ࢆࣀ࣮࣐ࣛࢬࡍࡿᇶ‽῝࡛ ࢿࣝࢠ࣮ࠊSSDࠊࣅ࣮࣒ಟ㣭ჾලࠊࣅ࣮࣒ゅ ᐃࡍࡿࠋTable I ♧ࡋࡓࢫࣉࣞࢵࢻࢩ࣮ࢺࡣከ㔞 ᗘ࡞ࢆྵࡴᵝࠎ࡞ᅉᏊᙳ㡪ࡉࢀࡿ 90-101ࠋ ࡢࢹ࣮ࢱࡢయ⣔ⓗ࡞⟶⌮᭷⏝࡛࠶ࡿࠋࡇࡢࡁࠊ ࡇࡢኚࡣ〇㐀ᴗ⪅ࡼࡿ㐺ṇ࡞ᢏ⾡ࡼ ྠࣇࣝྡ࡞ࡶ୍ᣓࡋ࡚⟶⌮ࡍࡿᚲせࡀ ࡾྍ⬟࡞㝈ࡾపῶࡉࢀ࡚࠸ࡿࡀࠊ㏻ᖖࠊྛ ࠶ࡿࠋ SSD ࠾ࡅࡿΰධ㟁Ꮚࡢኚࡣ⿵ṇ࡛ࡁ࡞ ࠸ 102, 103ࠋΰධ㟁Ꮚࡢ┦ᑐⓗ࡞㔞ࡣ✵Ẽᒙࡢ IV.A.1. ῝㒊⥺㔞 㛗ࡉ㸦ҸSSD㸧࡛ኚࡋࠊ㛗࠸ SSD ࡛ࡣ࣊ࢵ PDD ࡣ୍ᐃࡢ SSD㸦㏻ᖖࡢࣜࢽࢵࢡ࡛ࡣ⥺※ᅇ ࢻᩓ㟁Ꮚࡢ✵୰ᩓࡀቑࡍࡿࡓࡵΰධ ㌿㍈㛫㊥㞳࡛࠶ࡿ 100 cm㸧࡛ ᐃࡍࡿࠋཷࡅධࢀヨ 㦂࠾ࡅࡿ PDD ᐃ࡛ࡣ≉ᐃࡢ ᐃᶵჾ㸦࠼ࡤࠊ 㟁Ꮚࡣῶᑡࡍࡿࠋ x ୍ḟ⥺㔞㸦Primary dose㸧 㸸୍ḟ⥺㔞ࡣ␗࡞ࡿ ᕤሙฟⲴࡢࣅ࣮࣒ࣃ࣓࣮ࣛࢱ୍⮴ࡉࡏࡿࡓࡵࠊ SSD ᑐࡋ࡚㊥㞳ࡢ㏫๎ࢆ㐺⏝ࡍࡿࡇ ࣜࢽࢵࢡࡢタ⨨⪅ࡀ⏝࠸ࡿ Wellhofer Buddelschif ࡛⿵ṇྍ⬟࡛࠶ࡿࠋࡓࡔࡋࠊഃ᪉㟁Ꮚᖹ⾮ ࡸ PTW ࢩࢫࢸ࣒࡞㸧ࡀ⏝࠸ࡽࢀࡿࠋࡋࡋࠊࡇ ࡀᡂ❧ࡋ࡞࠸ᑠ↷ᑕ㔝࡛ࡣ῝ࡉࡼࡾ↷ᑕ ࢀࡽࡢࢹ࣮ࢱࡣࣅ࣮࣒ࣔࢹࣜࣥࢢࡸࢥ࣑ࢵࢩࣙࢽ 㔝ࢧࢬࡀኚࡋࠊᖹ⾮ࣞ࣋ࣝࡀኚࡍࡿࡓ ࣥࢢ࡛⏝࠸࡚ࡣ࡞ࡽ࡞࠸ࠋࡇࡢࠊࢫ࢟ࣕࣥ㏿ᗘࠊ ࡵ⿵ṇࡣᅔ㞴࡛࠶ࡿࠋ ࢫࢸࢵࣉࠊࢤࣥ࡞ὀពࡀᚲせ࡛࠶ࡿ㸦III ❶ཧ x ᩓ⥺㔞㸦Scatter dose㸧㸸↷ᑕ㔝࡛ࡣࣇ ↷㸧 ࠋࡲࡓࠊ῝㒊⥺㔞ࡢ ᐃ࡛ࡣỈ㠃ࡢἼ❧ࡕࢆ᭱ ࣥࢺ࣒ෆ࡛⏕ࡌࡿᩓ⥺ࡀቑࡍࡿࡓࡵ㊥ ᑠࡍࡿࡓࡵࠊࢱࣥࢡࡢᗏࡽ ᐃࢆ㛤ጞࡍࡿ࡞ 㞳ࡢ㏫ࡢᙳ㡪ࡀᙅࡲࡿࠋࡇࡢᩓ⥺ࡣ␗ ࢫ࢟ࣕࣥ᪉ྥࢆ⪃៖ࡍࡿᚲせࡀ࠶ࡿࠋ ࡞ࡿ SSD ࡛ྲྀᚓࡉࢀࡿ㸦ΰධ㟁Ꮚࡢ฿㐩῝ ᗘ௨㝆ࡢ㸧PDD ࡀᕪ␗ࢆ⏕ࡌࡿ࡞ཎᅉ࡛ IV.A.1.a. ᶆ‽ⓗ࡞ SSD 㠀ᶆ‽ⓗ࡞ SSD ྛ✀ࡢࢫࢣ࣮ࣜࣥࢢᡭᢏ࡛⏕ࡌࡿㄗᕪࢆ᭱ᑠ ࠶ࡿࠋ x ࡍࡿࡓࡵࠊࢹ࣮ࢱࡣ⮫ᗋ࡛ࡢࢭࢵࢺࢵࣉ᮲௳㏆ ࣊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ࣇࣛࢵࢺࢽࣥࢢࣇࣝࢱ㸧ࡽ Ṧ࡞⒪ἲ࡛ࡣࠊ῝㒊⥺㔞ࠊTPR ࡲࡓࡣ TMRࠊ⥺ ࡢ㏫ᚑ࠺ࠋ࣊ࢵࢻᩓගᏊࡢᐇຠ⥺※ 㔞ࣉࣟࣇࣝࡣࠊAAPM ࡢ࣏࣮ࣞࢺグ㏙ࡉࢀ࡚ ⨨ࡣࣇࣛࢵࢺࢽࣥࢢࣇࣝࢱ㏆࠶ࡿ ࠸ࡿࡼ࠺ࡑࢀࡒࢀᘏ㛗ࡋࡓ㊥㞳࡛ྲྀᚓࡍࡿᚲせ ࡓࡵࠊ㏫ࡢᙳ㡪ࡣࢱ࣮ࢤࢵࢺࡽࡢ┤᥋ ࡀ࠶ࡿ 23,24ࠋࡋࡋࠊỈᵴࡢࢧࢬࡀ㝈ᐃࡉࢀࡿࡓ ගᏊ࣊ࢵࢻᩓගᏊ࡛␗࡞ࡿࠋࡉࡽࠊ ࡵࡇࢀࡽࡢࢹ࣮ࢱ㞟ࡣᅔ㞴࡛࠶ࡿࠋࡉࡽࠊࡇࢀ PDD㸦┤᥋ගᏊ࣊ࢵࢻᩓගᏊࡢΰྜ㸧 ࡽࡢࢹ࣮ࢱࡣ༑ศ࡞ࢧࢬࡢࣇࣥࢺ࣒ࢆ⏝࠸ࡓ ഃ᪉ࡢ⥺㔞ࣉࣟࣇࣝ㸦ᐇຠ⥺※⨨ࡀࣇ ࣏ࣥࢺ⥺㔞 ᐃࡼࡗ᳨࡚ドࡍࡿᚲせࡀ࠶ࡿࠋ ࣥࢺ࣒㏆࡙ࡃࡓࡵࠊ࣊ࢵࢻᩓගᏊࡣ┤ x x ᥋ගᏊࡼࡾእഃᗈࡀࡿ㸧࡛␗࡞ࡿᙳ㡪ࢆࡶ IV.A.2. ⤌⧊᭱⥺㔞ẚ࣭⤌⧊ࣇࣥࢺ࣒⥺㔞ẚ ࡓࡽࡍࠋ 㸦TMR/TPR㸧 ࢚ࢿࣝࢠ࣮㸦Energy㸧㸸⾲㠃࡛ྠࡌ↷ᑕ㔝ࢧ TMR ࡢ ᐃࡣከ࡞㛫ࢆせࡍࡿࠋỈࣇࣥࢺ ࢬ࡛࠶ࡗ࡚ࡶࠊSSD ࡀ␗࡞ࡿሙྜࡣ␗࡞ࡿ ࣒ࡼࡗ࡚ࡣࠊ᪤▱ࡢỈ㔞ࢆ࣏ࣥࣉ࡛Ữࡳࡔࡍࡇ ᐇຠ࢚ࢿࣝࢠ࣮ࢫ࣌ࢡࢺࣝࢆ♧ࡍࠋࡇࢀࡣᩓ ࡼࡗ࡚ TMR/TPR ࢆ ᐃࡍࡿࢩࢫࢸ࣒ࢆ᭷ࡍࡿࡀࠊ ⥺ࡢᡂศࡀ␗࡞ࡿࡓࡵ࡛ࠊ㍈እ࠾ࡅࡿ⥺ ࡑࢀࡒࢀ࣏ࣥࢺ⥺㔞 ᐃࡼࡾṇ☜ࡉࢆ᳨ドࡍ ㉁ࡢ㌾ࡣ㍈እゅᗘ౫Ꮡࡍࡿࠋ ࡿᚲせࡀ࠶ࡿࠋ᭱ࡶ⡆༢࡞ TMR/TPR ࡢྲྀᚓἲࡣࠊ ༙ᙳ㸦Penumbra㸧㸸㟁㞳⟽ࡀࢧࢬࡼࡗ࡚ ῝㒊⥺㔞 ᐃࡽኚࡋ࡚సᡂࡍࡿ᪉ἲ࡛࠶ࡿࠋከ ᭷ពࡢᗈࡀࡾ㛵ᩘࢆᣢࡘࡓࡵࠊ㟁㞳⟽ࢆ⏝࠸ ࡃࡢࢯࣇࢺ࢙࡛࢘ࡣ BJR Supplement 25104 ♧ࡉ ࡚ ᐃࡋࡓ࠶ࡿ SSD ࡢ༙ᙳࡽࡢ SSD ࡢ ࢀࡓ Khan ࡽ 88 ࡢᡭἲࢆ᥇⏝ࡋࡓኚࣉࣟࢢ࣒ࣛࡀ ༙ᙳࢆỴᐃࡍࡿࡇࡣᅔ㞴࡛࠶ࡿࠋᑠᆺࡢ᳨ ⤌ࡳ㎸ࡲࢀ࡚࠸ࡿࠋ῝ࡉ d ↷ᑕ㔝 rd ࡢ TMR ࡣࠊ ฟჾࡀ⏝࡛ࡁ࡞࠸ሙྜࠊࣉࣟࣇࣝࡣࢹ PDD ࡽḟᘧ࡛⟬ฟ࡛ࡁࡿࠋ ࢥ࣮ࣥ࣎ࣜࣗࢩࣙࣥ㸦㏫␚ࡳ㎸ࡳ✚ศ㸧࡛ᚓ ࡿࡇࡀ࡛ࡁࡿ㸦Sec. IV A ཧ↷㸧ࠋ TMRd , rd 㸦ᑠ↷ᑕ㔝ࢆ㝖ࡃ㸧⡆༢࡞ QA ࡛ࡣࠊഹ࡞ SSD PDDc, d r , SSD SSD d 2 S p r , c d max . 100 SSD d max 2 S p r , c d (2) ࡢ㐪࠸ᑐࡋ࡚㏫๎ࡼࡿ⿵ṇࡀྍ⬟࡛࠶ࡿࠋ ࡓࡔࡋࠊࡑࢀ௨እ࡛ࡣ␗࡞ࡿ SSD ࡛ᚓࡓࢹ࣮ࢱࢆ⿵ ṇࡋ࡚⏝࠸ࡿࡇࡣ᥎ዡࡉࢀ࡞࠸ࠋ IV.A.1.b. ␗࡞ࡿ SSD ࠾ࡅࡿ PDD ࡢኚ PDD ࡣࠊSSD ୍ᐃࡢ⒪ࡸࡑࡢࡢ῝㒊⥺㔞ࢹ࣮ ࢱ㸦࠼ࡤ TMR/TPR㸧ࢆỴᐃࡍࡿࡓࡵ⏝࠸ࡽࢀ ࡿࠋ័⩦ⓗ PDD ࡣ SSD=100 cm ࡛ホ౯ࡉࢀࡿࡀࠊ SSD=90 cm ࡞࡛ࡶ ᐃࡉࢀࡿࡇࡀ࠶ࡿࠋ▷࠸ SSD ࡛ࡣ↷ᑕ㔝ࡢ ᐃ࡛༑ศ࡞ࣇࣥࢺ࣒ࢧ ࢬࢆᐜ᫆‽ഛ࡛ࡁࡿࠋPDD ࡣ↷ᑕ㔝㸦s㸧῝ࡉ 㸦d㸧ຍ࠼ SSD ࡢ㛵ᩘ࡛࠶ࡿࠋ␗࡞ࡿ SSD ࡛ ᐃ ࡉࢀࡓ 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ࡸ⓶㟁 ኚࡢጇᙜᛶࢆ☜ㄆࡍࡿࡓࡵࠊᘧ(2)࡛ᚓࡓ TMR ࡣ↷ᑕ㔝ࠊᑠ↷ᑕ㔝࠾ࡼࡧ῝㒊࡛ᚲࡎ᳨ドࡋ࡞ࡅ ࢀࡤ࡞ࡽ࡞࠸ࠋࡲࡓࠊࡇࢀࡽࡢ⾲ࡢసᡂࡣ PDD ࡢ⿵㛫ࡀᚲせ࡛࠶ࡿࡓࡵࠊᑠ↷ᑕ㔝ࡢ TMR ࡛ࡣࡉ ࡽᑠ↷ᑕ㔝ࡢ PDD ࡀᚲせ࡛࠶ࡿࠋ࣋ࣥࢲ࣮ࡀᥦ ౪ࡍࡿࢯࣇࢺ࢙࢘ࢆ⏝࠸࡚ PDD ࡽ TMR ኚ ࡍࡿሙྜࠊᑠ↷ᑕ㔝῝㒊࡛ࡣእᤄࡼࡿㄗᕪࡀ⏕ ࡌ࡚࠸࡞࠸ࡇࢆᚲࡎ☜ㄆࡍࡿᚲせࡀ࠶ࡿࠋ࣏ࣥ ࢺ⥺㔞 ᐃࡼࡾࡇࢀࡽࡢጇᙜᛶࢆ☜ㄆࡍࡿࡇ ࢆ᥎ዡࡍࡿࠋ IV.A.3. ⾲㠃⥺㔞ࣅࣝࢻࢵࣉ㡿ᇦ ⾲㠃⥺㔞ࡣ⨨౫Ꮡࡋࠊ↷ᑕ㔝ࢧࢬࠊ⥺※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. ࣜࢽࢵࢡࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ࡛ࡣ⾲㠃⥺㔞ࡢ ᐃࡀྵࡲࢀࡿࠋࣅࣝࢻࢵࣉ㡿ᇦྠᵝࠊ⾲㠃㏆ ࡣᛴᓧ࡞⥺㔞໙㓄࡛࠶ࡿࡓࡵ᳨ฟჾࡢ㑅ᢥ⣽ᚰ ࡢὀពࡀᚲせ࡛࠶ࡿ 115-118ࠋFig. 10 ࡣ␗࡞ࡿ᳨ฟჾ ࡛ ᐃࡋࡓࣅࣝࢻࢵࣉ㡿ᇦ⾲㠃⥺㔞ࢆ♧ࡍࠋ㏻ ᖖࠊࣅ࣮࣒᪉ྥࡢ᳨ฟჾ᭷ឤ㒊ࡢࡁࡉࡣྍ⬟࡞㝈 ࡾᑠࡉࡃࡍࡿࠋ⾲㠃⥺㔞ࡢ ᐃ࡛ࡣ㉮ᰝᘧࡢ ᐃჾ ࢆ⏝ࡋ࡞࠸ࡇࢆᙉࡃ᥎ዡࡍࡿࠋ FIG. 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. ⾲㠃⥺㔞ࡢ ᐃ࡛ࡣእᤄ㟁㞳⟽ࡀ᭱㐺࡛࠶ࡿࠋࡋ ࡋࠊධᡭᅔ㞴࡛࠶ࡾࠊ㠀ᖖ ᐃ㛫ࡀࡿၥ 㢟ࡀ࠶ࡿࠋࡼࡗ࡚ࠊࡑࡢ௦⏝ࡋ࡚ᖹ⾜ᖹᯈᙧ㟁㞳 ᑠ↷ᑕ㔝⥺㔞໙㓄ࡀᛴᓧ࡞㡿ᇦ࠾ࡅࡿ⥺㔞 ⟽ࡀ⾲㠃⥺㔞ࣅࣝࢻࢵࣉ㡿ᇦࡢ⥺㔞 ᐃ୍࡛ ࣉࣟࣇࣝ㸦㸻㍈እ⥺㔞ẚ㸧ࡢ ᐃ࡛ࡣࠊ᳨ฟჾ ⯡ⓗ⏝࠸ࡽࢀ࡚࠸ࡿࡀࠊᖹ⾜ᖹᯈᙧ㟁㞳⟽ࡣࣅࣝ ࡢタ⨨᪉ྥࡀᴟࡵ࡚㔜せ࡛࠶ࡿࠋFig. 11 ♧ࡍࡼ࠺ ࢻࢵࣉ㡿ᇦࠊ≉⾲㠃㏆ഐ࡛⥺㔞ࢆ㐣ホ౯ࡍࡿ ࠊẚ㍑ⓗࡁ࠸↷ᑕ㔝࠾ࡅࡿ⥺㔞ࣉࣟࣇࣝ 90, 119 ᐃ࡛ࡣࠊ㐺ษ࡞᳨ฟჾࡑࡢタ⨨᪉ྥࡀ㑅ᢥࡉࢀ ࠋࡇࢀࡣእᤄ㟁㞳⟽ẚ㍑ࡋ࡚㟁ᴟ㛫㝸ࡀࡁ ࠸ࡇࠊ࣮࢞ࢻࣜࣥࢢࡀᑠࡉ࠸ࡇ㉳ᅉࡍࡿࠋ ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋFig. 11 ࡣࣉࣟࣇࣝ ᐃ࠾ ࡼࡗ࡚ࠊᑠࡉ࠸㟁ᴟ㛫㝸ᖜࡢᗈ࠸࣮࢞ࢻࣜࣥࢢࢆ ࡅࡿయ✚ᖹᆒຠᯝࢆ♧ࡋࠊࢫ࢟ࣕࣥ᪉ྥ࡛᭷ឤ㒊ࡀ ഛ࠼ࡓ㟁㞳⟽ࢆ⏝࠸ࡿࡇ࡛ࡇࡢṇ☜ࡉࡣపῶ ⷧ࠸㸦✵㛫ศゎ⬟ࡀ㧗࠸㸧᳨ฟჾࡀࣉࣟࣇࣝ ࡛ࡁࡿࠋࡉࡽࠊ㟁㞳⟽ࡢᴟᛶຠᯝࡣṇ㈇ࡢᴟᛶ࡛ 90 ᚓࡽࢀࡓㄞࡳ್ࢆᖹᆒࡍࡿࡇ࡛⿵ṇྍ⬟࡛࠶ࡿ ࠋ ᐃ㐺ࡋ࡚࠸ࡿࠋ ㏻ᖖࠊࢥ࣑ࢵࢩࣙࢽࣥࢢ࡛ࡣ in-plane㸦gun-target ⷧᒙ TLDࠊ᭷ឤయ✚ࡢᑠࡉ࠸ࢲ࣮࢜ࢻ᳨ฟჾࠊ ᪉ྥ㸧 cross-plane㸦left-right ᪉ྥ㸧ࡢ⥺㔞ࣉࣟࣇ MOSFETࠊࣛࢪ࢜ࢡ࣑ࣟࢵࢡࣇ࣒ࣝࡼࡿ⾲㠃⥺ ࣝࡀᚲせ࡛࠶ࡿࠋin-plane cross-plane ࢆ௵ព 㔞ࡢ ᐃࡶሗ࿌ࡉࢀ࡚࠸ࡿ 117,120,121 ࠋ 㑅ᢥ࡛ࡁࡿሙྜࠊcross-plane ࣉࣟࣇࣝࢆྲྀᚓ ࡍࡁ࡛࠶ࡿࠋࡇࢀࡣࠊ୍㒊ࡢ⨨࡛ࡣຍ㏿㟁Ꮚࢆ IV.A.4. ࣅ࣮࣒ࣉࣟࣇࣝ ㄪᩚࡍࡿ gun-target ᪉ྥ࡛ࠊ㠀ᑐ⛠ᛶࡸᖹᆠᛶࡀḞ IV.A.4.a. ࣉࣟࣇࣝ㸦༙ᙳ㒊㍈እ⥺㔞ẚ㸧 ዴࡍࡿྍ⬟ᛶࡀ࠶ࡿࡓࡵ࡛࠶ࡿࠋcross-plane ࡢࣉࣟ 40 IV. 光子線のビームデータ Jpn. J. Med. Phys. Vol. 33 No. 1 (2013) ࣇࣝࡣᏳᐃࡋ࡚࠾ࡾࠊࢹ࣮ࢱ㞟࡛ࡣࡇࡢ㉮ᰝ ࣇࣝࡶ ᐃࡍࡿࠋ⥺㔞໙㓄ࡀᛴᓧ࡞㡿ᇦ࡛ࡣࡼ ᪉ྥࢆ㑅ᢥࡍࡿᚲせࡀ࠶ࡿࠋ ࡾᑠࡉ࠸㛫㝸࡛ ᐃࡍࡿᚲせࡀ࠶ࡿࠋ≀⌮࢙࢘ࢵࢪ ⥺㔞ࣉࣟࣇࣝࡣࠊࢥ࣑ࢵࢩࣙࢽࣥࢢᮇ㛫 ࡛ࡣ໙㓄᪉ྥ㠀໙㓄᪉ྥ࡛ࣅ࣮࣒ࡢῶᙅࡀ⏕ࡌ TPS ࡢධຊࡸࡑࡢࡢᡭィ⟬ࠊᕷ㈍ࡢࢯࣇࢺ࢙࢘ ࡿࠋ↷ᑕ㔝ࡢ㎶⦕࡛ࡣ࢙࢘ࢵࢪᩳධᑕࡍࡿࡇ ࢆ⏝࠸ࡓ MU ィ⟬⏝ྲྀᚓࡍࡿࠋ ᐃ᮲௳ࡣ TPS ࡼࡾࠊ㍈እ࡛࠶ࡿῶᙅࡀࡁ࠸ࡇὀពࡀ ౫Ꮡࡍࡿࡀࠊከࡃࡢ TPS ࡛ࡣ࣮࢜ࣉ࢙ࣥ࢘ࢵࢪ ᚲせ࡛ࠊࡇࢀࢆホ౯ࡍࡿࡓࡵࠊ㠀໙㓄᪉ྥ࡛ࡶࢹ࣮ ↷ᑕ㔝ࡘ࠸࡚༙ᙳ㒊㍈እ⥺㔞ẚࢆࣔࢹࣝࡍ ࢱࢆྲྀᚓࡍࡿ 123, 124ࠋ ࡿࡓࡵࠊᑠ↷ᑕ㔝ࡽ᭱↷ᑕ㔝ࡢ⥺㔞ࣉࣟࣇ ࣝࢆᚲせࡍࡿࠋࢹ࣮ࢱ㛫㝸ࡣ༙ᙳ㒊࡛ᑡ࡞ࡃࡶ 1 mmࠊࡑࡢࡣ 2 mm ࢆ㉸࠼࡞࠸㛫㝸ࡀᮃࡲࡋ࠸ࠋ IV.A.4.d. ࢯࣇࢺ㸦࢚ࣞࢡࢺࣟࢽࢵࢡ㸧࢙࢘ࢵࢪ ࢯࣇࢺࡲࡓࡣ࢚ࣞࢡࢺࣟࢽࢵࢡ࢙࢘ࢵࢪ㸦ࢲࢼ ࣉࣟࣇࣝࢹ࣮ࢱࡽ㍈እ⥺㔞ẚࡢ⾲ࢆసᡂࡍ ࣑ࢵࢡ࢙࢘ࢵࢪࠊࣂ࣮ࢳ࢙ࣕࣝ࢘ࢵࢪ㸧ࡢ⥺㔞ࣉࣟ ࡿ㝿ࡣ୰ᚰ㍈ࡢ್࡛つ᱁ࡋࠊࢯࢭࣥࢱ㠃࡛ࡢ ࣇࣝࢆ ᐃࡍࡿࡓࡵࡣࠊ୍⯡ⓗ࡞ࢫ࢟ࣕࢽࣥ ㍈እ㊥㞳⦰ᑻࢆྜࢃࡏࡿᚲせࡀ࠶ࡿࠋከࡃࡢࢫ࢟ ࢢࢩࢫࢸ࣒ࡣ␗࡞ࡿ ᐃᶵჾࡀᚲせ࡛࠶ࡿࠋࢯࣇ ࣕࢽࣥࢢࢩࢫࢸ࣒ᒓࡍࡿࢯࣇࢺ࢙࢘ࡣࡇࡢ ࢺ࢙࢘ࢵࢪࡣࣅ࣮࣒↷ᑕࢥ࣓࣮ࣜࢱࢆ㛤㛢㥑 ᶵ⬟ࢆഛ࠼࡚࠸ࡿࠋ ືࡍࡿࠋࡇࡢሙྜࡢ࢙࢘ࢵࢪࣉࣟࣇࣝࡣ༢୍ࡢ ⥺㔞ࣉࣟࣇࣝࡢ ᐃᩘࡣ TPS ౫Ꮡࡋࠊᐃࡵ 㟁㞳⟽ࢆ⏝ࡍࡿᶆ‽ࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡛ ࡽࢀࡓ↷ᑕ㔝῝ࡉ࡛ྲྀᚓࡍࡿࠋࣅ࣮࣒ࡢᇶᮏⓗ࡞ ࡣ ᐃ࡛ࡁ࡞࠸ࠋྛ ᐃⅬ࡛ᩓ⥺ࡢᙳ㡪ࢆ⪃៖ ᙧ≧ࡣ῝ࡉࡲࡓࡣ↷ᑕ㔝࡛ࡁࡃኚࡋ࡞࠸ࡓࡵࠊ ࡋࡓ ᐃࢆ⾜࠺ࡓࡵࠊࣇ࣒ࣝࡸࠊࢫ࢟ࣕࢽࣥࢢࢩ ࣉࣟࣇࣝࡣ㐣ྲྀᚓࡍࡿᚲせࡣ࡞࠸ࠋ㏻ᖖࠊ ࢫࢸ࣒ࡢ㥑ື㒊࣐࢘ࣥࢺ࡛ࡁࡿ㸯ḟඖ᳨ฟჾ㸦ิ 2 2 6 × 6 cm ࡲ࡛ࡣ 1 cm 㛫㝸ࡢ↷ᑕ㔝ࠊ10 × 10 cm ௨ ᆺ᳨ฟჾࠊ⣲Ꮚࡣ㟁㞳⟽ࡲࡓࡣࢲ࣮࢜ࢻ㸧44, 45, 59 ୖ࡛ࡣ 5 cm 㛫㝸ࡢ↷ᑕ㔝࡛ྲྀᚓࡍࢀࡤ༑ศ࡛࠶ࡿࠋ ࡀ⏝࠸ࡽࢀࡿࠋࡋࡋࠊከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ ࡲࡓ῝ࡉࡘ࠸࡚ࡣ 5-7 ✀㢮ࡢ῝ࡉ࡛ྲྀᚓࡋࠊdmax ࣒࡛ࡣࡇࡢ࣐࢘ࣥࢺ࢜ࣉࢩࣙࣥ࡞⤌ࡳྜࢃࡏ࡚ ࢆྵࡴ 5 cm 㛫㝸࡛༑ศ࡛࠶ࡿࠋࡲࡓࠊ୍㒊ࡢ TPS ⏝࡛ࡁࡿ᳨ฟჾไ㝈ࡀ࠶ࡾࠊࡲࡓタࡼࡗ࡚ ࡛ࡣ in-plane cross-plane ຍ࠼ᑐゅ⥺ୖ ࡣ㈝⏝ࡶၥ㢟࡞ࡿࠋࡑࡢࡢ㑅ᢥ⫥ࡋ࡚ Profiler 㸦diagonal-plane㸧ࡢࣉࣟࣇࣝࡀᚲせ࡛࠶ࡿࠋ 㸦Sun Nuclear, Melbourne, FL㸧ࡢࡼ࠺࡞ࢲ࣮࢜ࢻ ࣞࠊࡰỈ➼౯ࡉࢀࡿᅛయࣇࣥࢺ࣒ࢆ⏝ IV.A.4.b. ࢫࢱ࣮ࣃࢱ࣮ࣥ ࠸࡚ᑡ࡞ࡃࡶ 20 cm ࡲ࡛ࡢ␗࡞ࡿ῝ࡉ࡛ ᐃࡍࡿ ୍㒊ࡢ TPS ࣝࢦࣜࢬ࣒࡛ࡣࢥ࣓࣮ࣜࢱᅇ㌿㍈ ᪉ἲࡀ࠶ࡿࠋࢲ࣮࢜ࢻࣞࡣỈ୰ࢫ࢟ࣕࣥⰋ ᆶ┤࡞㠃ࡢ࠸ࡃࡘࡢゅᗘ࡛⥺㔞ࣉࣟࣇࣝ ዲ࡞୍⮴ࢆ♧ࡋ࡚࠾ࡾ 45ࠊTPS ࡢࢹ࣮ࢱ㌿㏦ࡀྍ ࡀᚲせ࡞ሙྜࡀ࠶ࡿࠋࡇࡢ⥺㔞ࣉࣟࣇࣝࡣ୍⯡ ⬟࡛࠶ࡿሙྜࡀከ࠸ࠋࡓࡔࡋࠊࢲ࣮࢜ࢻࣞࡣ ⓗ 10r㛫㝸ࠊ᭱↷ᑕ㔝ࡢ dmax ࡲࡓࡣỈ୰῝ࡉ ᐃྍ⬟࡞᭱↷ᑕ㔝ࡀ㝈ࡽࢀ࡚࠸ࡿࠋࡑࡢࡢ㑅 10 cm ࡛ྲྀᚓࡉࢀࠊࢫࢱ࣮ࣃࢱ࣮ࣥ㸦star-pattern㸧 ᢥ⫥ࡋ࡚ࡣࠊࣇ࣒ࣝࢆᅛయࣇࣥࢺ࣒ᤄධࡋࠊ ࡤࢀࡿࠋ୍㒊ࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣ≉ᐃࡢゅ ⏬ീゎᯒࢯࣇࢺ࡛⥺㔞ࣉࣟࣇࣝࢆྲྀᚓࡍࡿ᪉ ᗘ࡛ࢫࢱ࣮ࣃࢱ࣮ࣥࢆྲྀᚓࡍࡿࢯࣇࢺ࢙࢘ࡀෆ ἲࡀ࠶ࡿࠋࣇ࣒ࣝࢆ⏝࠸ࡓ⥺㔞 ᐃ࡛ࡣ⃰ᗘ-⥺㔞 ⶶࡉࢀ࡚࠸ࡿࠋࢯࣇࢺ࢙࢘ࡀ⏝࡛ࡁ࡞࠸ሙྜࡣࠊ ᛂ⟅᭤⥺ࢆసᡂࡋ࡚ᰯṇࢆ⾜࠺ᚲせࡀ࠶ࡾࠊࡲࡓ⮬ ⨨ࡢ࢝࢘ࢳᅇ㌿ྎ࡛Ỉᵴࢆᅇ㌿ࡍࡿࡇ࡛ྲྀᚓ ື⌧ീᶵࡢ QA ࡶᚲ㡲࡛࠶ࡿࠋࣇ࣒ࣝࢆ⏝࠸ࡓ⥺ ࡍࡿࠋࢫࢱ࣮ࣃࢱ࣮ࣥࡣࣇࣛࢵࢺࢽࣥࢢࣇࣝࢱࡢ 㔞 ᐃࡢၥ㢟Ⅼࡣ≉ᛶ᭤⥺ࡢ⥺㉁౫Ꮡᛶ 21 ࣇࣝ ≉ᛶ㸦ᙧ≧ሗ㸧ࢆỴᐃࡍࡿࡓࡵࡢࡶࡢ࡛࠶ࡿࡢ࡛ࠊ ࣒ࢧࢬࡼࡿ ᐃ⠊ᅖࡢไ㝈࡛࠶ࡿࠋ ࢥ࣓࣮ࣜࢱࢆᅇ㌿ࡋ࡚ྲྀᚓࡋ࡚ࡣ࡞ࡽ࡞࠸ 122 ࠋ IV.B. MLC ࢹ࣮ࢱ IV.A.4.c. ≀⌮㸦ࣁ࣮ࢻ㸧࢙࢘ࢵࢪ Table I(a)♧ࡍࡼ࠺ࠊ࢙࢘ࢵࢪ᪉ྥࡢ⥺㔞ࣉࣟ ㏆ᖺࠊMLC ࡣࣜࢽࢵࢡᶆ‽ᦚ㍕ࡉࢀ࡚࠾ࡾࠊ ⏝㏵ྜࢃࡏ࡚ᵝࠎ࡞ࢧࢬ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 ࡞ࡃࡶᡭィ⟬ࡼࡿ⥺㔞ィ⟬࡛ࡣ௨ୗࡢࢹ࣮ࢱ 㐀ᴗ⪅ᑐࡍࡿሗ࿌ᇶ࡙࠸࡚ࠊ⨨ࡢࢡࢭࣉࢱ ࢆ㞟ࡍࡿᚲせࡀ࠶ࡿࠋ ࣥࢫࢸࢫࢺ᳨࡛ドࡉࢀ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ 125-145 ࠋ㏻ ᖖࠊMLC ࡢྲྀᚓࡍࡁࢥ࣑ࢵࢩࣙࢽࣥࢢࢹ࣮ࢱࡣ IV.C.1. ᩓಀᩘ ⮫ᗋ⏝౫Ꮡࡍࡿࡀࠊࡑࢀ௨ୖ TPS ౫Ꮡࡍࡿࠋ ⒪⨨ࡢฟຊಀᩘࡣࠊᇶ‽࡞ࡿỈ୰῝ࡉࡢ↷ MLC ࡢタィࢥ࣑ࢵࢩࣙࢽࣥࢢ㛵ࡍࡿヲ⣽ࡣ ᑕ㔝㸦10 × 10 cm2㸧ᑐࡍࡿ௵ពࡢ↷ᑕ㔝ࡢ⥺㔞ẚ AAPM Report 72 145 IPEM Report 94 16 ࡛ᥦ౪ࡉࢀ ࡋ࡚ᐃ⩏ࡉࢀࡿࠋᩓಀᩘ㸦Total scatter factor, ࡚࠸ࡿࠋࡋࡋࠊୗグࡢࣃ࣓࣮ࣛࢱࡣྛගᏊ࢚ࢿࣝ Scp㸧ࡣྠࡌ MU タᐃ್㸦M㸧࠾࠸࡚࠶ࡿ↷ᑕ㔝 ࢠ࣮ࠊ㔜ຊࡢᙳ㡪ࢆ᳨ドࡍࡿࡓࡵࠊᑡ࡞ࡃࡶ 4 ᇶ‽↷ᑕ㔝ࡢ⥺㔞ẚࡋ࡚ᐃ⩏ࡉࢀࡿࠋ୧⪅ࡣ༑ศ ࡘࡢ࢞ࣥࢺࣜゅᗘ㸦0°ࠊ90°ࠊ180°ࠊ270°㸧࡛ᐃ㔞 ࡁ࠸Ỉࣇࣥࢺ࣒୰࡛ᇶ‽῝タ⨨ࡋࡓ⥺㔞 ࡉࢀ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ 146, 147 ࠋ ィ࡛ ᐃࡍࡿࠋ S cp ( s ) x ග↷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 ຠᯝ x ༙ᙳ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⥺㔞࡛࠶ࡾࠊM ࡣ MU タᐃ್࡛࠶ࡿࠋྛ↷ᑕ㔝࡛ഃ᪉ྥࡢࣅࣝࢻ ࢵࣉࢆ☜❧ࡉࡏࡿࡓࡵࠊࡁ࠸ࢧࢬࡢỈࣇࣥࢺ ຍ࠼࡚ࠊ⥺㔞 ᐃ࡛㔜せ࡞ࡿ⨨ࡢṇ☜ࡉࡣࣇ 147, 149 ࣒ࢆ⏝ࡍࡿࠋ῝ࡉ᪉ྥࡣᚋ᪉ᩓࢆ⪃៖ࡋࠊ᭱῝ ࠋMLC ࡢඛ➃ ࡢ ᐃⅬࡽᑡ࡞ࡃࡶ 10 cm ࡣࣇࣥࢺ࣒ࡀᚲせ ࡀ‴᭤ࡋ࡚࠸ࡿሙྜ㸦ࣛ࢘ࣥࢻ࢚ࣥࢻ MLC㸧ࡣࠊ ࡛࠶ࡿࠋࡲࡓࠊᩓಀᩘࡣ ᐃ῝࡛ኚࡋࠊ࠼ 50%➼⥺㔞⥺ࡀ MLC ඛ➃୍⮴ࡋ࡞࠸ࡇࢆ⪃៖ ࡤ῝ࡉ 10 cm dmax ࡛ࡣࡃ␗࡞ࡿࡇὀពࡍࡿ ࡋ࡚ MLC ⨨ࡢ࢜ࣇࢭࢵࢺ㊥㞳ࢆỴᐃࡍࡿᚲせࡀ ᚲせࡀ࠶ࡿࠋ ᐃ๓ᚲせ࡞ࢹ࣮ࢱࢆ☜ㄆࡋ࡚࠾ࡃ ࣒ࣝࡲࡓࡣ EPID ࡛Ỵᐃࡍࡿ ࠶ࡿ 141 ࠋ༙ᙳ㒊ࢆ㝖ࡃୖグࡢࣃ࣓࣮ࣛࢱࡣ࡚ࣇ ࡇࡀ㔜せ࡛࠶ࡿࠋ ࣒ࣝࢆ⏝࠸ࡓ⥺㔞 ᐃࡼࡗ࡚ྲྀᚓࡋ࡞ࡅࢀࡤ࡞ ࡽ࡞࠸ࠋMLC 㛫㝽 㸦inter-leaf㸧 MLC ୰㸦intra-leaf㸧 IV.C.1.a. ᐃ ࡢ₃ὤ⥺㔞ࡣ㧗࠸ゎീᗘࢆࡶࡘࣇ࣒ࣝ EPID ࡛ Table I ♧ࡉࢀࡿࡼ࠺ࠊฟຊಀᩘࡣᇶ‽Ⅼ㸦ࠊ ᐃ࡛ࡁࡿࠋࣂࢵࢡࢵࣉ⏝ࡢ jaw ࢆక࠺ MLC ࡛ 10 cm ࡲࡓࡣ dmax㸧ࠊSSD ࡲࡓࡣ SAD=100 cm ࠾࠸ ࡣࠊjaw ࢆ᱁⣡ࡋࡓ≧ែ࡛ྲྀᚓࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋ ࡚ྛ↷ᑕ㔝ࢧࢬ࡛ ᐃࡍࡿࠋ⌮ⓗࡣࠊࣔࢽࢱ ගᏛ⃰ᗘ⥺㔞ࡢ㛵ಀࢆᚓࡿࡓࡵࠊࣜࣇࣞࣥࢫࣇ 㟁㞳⟽ࡢᰯṇྠࡌ᪉ἲ㸦SSD ἲࡲࡓࡣ SAD ἲ㸧 ࣒ࣝࡣᇶ‽῝࡛↷ᑕࡍࡁ࡛࠶ࡿࠋࡑࡢࡢ jaw ࡛ฟຊಀᩘࡢ ᐃࢆ⾜࠺ࡇࡀᮃࡲࡋ࠸ࠋIMRT ࡛ ࢆ㛤ࡋ MLC ࡢࡳ㛢ࡋࠊ࡚ࡢ MLC ࡀྵࡲࢀࡿ ࡣࠊᑠ↷ᑕ㔝ࡢฟຊಀᩘࡀᚲせ࡛࠶ࡿࡓࡵᑠᆺ㟁㞳 ࡁ࠸ࢧࢬࡢࣇ࣒ࣝࢆ⏝࠸࡚↷ᑕࡍࡿࠋMLC ⟽ࢆ⏝࠸ࡿࠋ㟁㞳⟽ࡢయ✚ᖹᆒຠᯝࢆ㑊ࡅࡿࡓࡵࠊ ↷ᑕ㔝ࢧࢬẚ㍑ࡋ࡚ࣇ࣒ࣝࡀᑠࡉ࠸ࡁࡣ 㟁㞳⟽ࢧࢬࡣ᭱ᑠ↷ᑕ㔝ẚ㍑ࡋ࡚ᑡ࡞ࡃࡶ ▷࠸ SSD ࡛ ᐃࡍࡿࠋࡇࢀࡣᇶ‽↷ᑕࡢ 10~20 ಸᚲ 㸦┤ᚄࡲࡓࡣ㛗ࡉࡢ㸧ྛഃ㠃࡛ 0.5 cm ࡣᑠࡉࡃ࡞ࡅ せ࡞ࡿ MU ࢆపῶࡍࡿࡇࡶᙺ❧ࡘࠋMLC 㛫 ࢀࡤ࡞ࡽ࡞࠸ࠋࡇࢀࡽᑠᆺ㟁㞳⟽࡛ᚓࡓࢹ࣮ࢱࡣẚ 㝽 MLC ୰ࡢ₃ὤ⥺㔞ࢆྲྀᚓࡍࡿࡓࡵࠊࣇ࣒ࣝ ㍑ⓗࡁ࠸↷ᑕ㔝࡛ࡁ࠸ࢧࢬࡢ㟁㞳⟽࡛ ᐃ ࡣ⌧ീᚋࢫ࢟ࣕࣥࡋࠊගᏛ⃰ᗘࢆ⥺㔞ኚࡍࡿ ࡋࡓࢹ࣮ࢱẚ㍑ࡋࠊ↷ᑕ㔝ᑐࡍࡿ Scp ᭤⥺ࡀⰋ ᚲせࡀ࠶ࡿࠋࡉࡽࠊྲྀᚓࡋࡓ MLC ₃ὤ⥺㔞ࡣ࣓ ዲ୍⮴ࡋࠊࢫ࣒࣮ࢬࡘ࡞ࡀࡿࡇࢆ☜ㄆࡍࡿࡇ ࣮࣮࢝ࡈᩥ⊩್ẚ㍑ࡍࡿᚲせࡀ࠶ࡿ 150 ࠋ ࡀᮃࡲࡋ࠸ࠋࡇࡢሙྜࠊᑠᆺ㟁㞳⟽ࡣᇶ‽࡞ࡿ ↷ᑕ㔝 10 × 10 cm2 ࡛㢧ⴭࢫࢸ࣒ຠᯝࡸࢣ࣮ࣈࣝ IV.C. ගᏊ⥺࣏ࣥࢺ⥺㔞ࢹ࣮ࢱ ྛ TPS ࡛ᚲせ࡞ࢹ࣮ࢱࡣᵝࠎ࡛࠶ࡿࠋࡋࡋࠊᑡ 42 ↷ᑕࡢᙳ㡪ࢆ♧ࡍྍ⬟ᛶࡀ࠶ࡿࠋࡲࡓࠊ3 × 3 cm2 ௨ ୗ࡛ࡣ㟁㞳⟽ࡢㄞࡳ್య✚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ࣉࣟࣇࣝ౫Ꮡࡋ ࡚ 5-10%⛬ᗘప࠸್ࢆ♧ࡍሙྜࡀ࠶ࡿ 151-153 ࠋ ࣥࢺ࣒࡛⏕ࡌࡓᩓ⥺ࡼࡿ⾪✺࣮࣐࢝ࡣྵࡲ࡞ ࠸ࡇὀពࡀᚲせ࡛࠶ࡿࠋ ᐇ㦂ⓗࠊSc ࡣΰධ㟁Ꮚࢆ㝖ࡍࡿ༑ศ࡞ཌࡉࡢ IV.C.1.b. ࣔࣥࢸ࢝ࣝࣟἲࡼࡿࣉ࣮ࣟࢳ ࣑ࢽࣇࣥࢺ࣒ࢆ⏝࠸࡚ࠊ㟁㞳⟽࡛ ᐃࡋࡓ㟁Ⲵࡢ ࣔࣥࢸ࢝ࣝࣟἲࡣᨺᑕ⥺⒪㛵ࡍࡿ≀⌮ⓗ࡞ ẚࡽồࡵࡿ 32ࠋ࣑ࢽࣇࣥࢺ࣒ࡢഃ᪉ྥࡢࢧࢬ ࣉࣟࢭࢫࢆṇ☜ࣔࢹࣝࡍࡿࡇࡀ࡛ࡁࠊࢇ࡞ ࡣ᳨ฟჾ⨨࡛ഃ᪉㟁Ꮚᖹ⾮ࡀᡂ❧ࡋࠊྠഃ᪉ 」㞧࡞ࢪ࣓࢜ࢺ࡛ࣜ࠶ࡗ࡚ࡶຠᯝⓗ࡛࠶ࡿࡇ ࡽࡢΰධ㟁Ꮚࢆྲྀࡾ㝖ࡃࢧࢬࡍࡁ࡛࠶ࡿࠋ ࡀド᫂ࡉࢀ࡚࠸ࡿ 154-156 ࠋཎ⌮ⓗࡣࠊPhase-space ࡲࡓࠊ࣑ࢽࣇࣥࢺ࣒ࡢ⤌ᡂࡣៅ㔜㑅ᢥࡋ࡞ࡅࢀ ࢹ࣮ࢱ㸦⢏Ꮚሗࢹ࣮ࢱ㸧ࢆ⏝ࡋࠊ㐺ษ࡞࣋ࣥࢳ ࡤ࡞ࡽࡎࠊc cref 㛫ࡢࢫ࣌ࢡࢺࣝࡢ㐪࠸ࡼࡗ࡚≀ ࣐࣮ࢡࢸࢫࢺࢆ⾜࠺ࡇࡼࡗ࡚ࢇ࡚ࡢ ㉁౫Ꮡࡋࡓ᭷ព࡞Ỉ୰࣮࣐࢝ẚࡢᕪࢆ⏕ࡌࡉࡏ ≧ἣ࡛ṇ☜࡞⥺㔞ィ⟬ࡀྍ⬟࡛࠶ࡿࠋヲ⣽࡞ຍ㏿ჾ ࡞࠸ࡇࡀ㔜せ࡛࠶ࡿࠋࡋࡋࠊ⥺㉁ࡀᇶ‽᮲௳ ࣊ࢵࢻࢪ࣓࢜ࢺࣜࢆ⏝࠸ࡓࢩ࣑࣮ࣗࣞࢩࣙࣥࡼ ࡽ␗࡞ࡿ᮲௳ୗ㸦ࠊ≀⌮࢙࢘ࢵࢪࡢ⏝㸧࡛ࡣࠊ ࡗ࡚ࠊࣔࣥࢸ࢝ࣝࣟἲࡣຍ㏿ჾ࣊ࢵࢻ㒊ࡢྛᵓᡂせ Sc ࡣ࢚ࢿࣝࢠ࣮ࣇ࢚ࣝࣥࢫẚࡢホ౯್࡛࠶ࡾࠊ⾪✺ ⣲࡛⏕ࡌࡿ⢏Ꮚሗࢆṇ☜Ỵᐃ࡛ࡁࡿࡓࡵࠊࣅ࣮ ࣮࣐࢝ ᐃ῝ࡲ࡛ࡢῶᙅࡼࡗ࡚ኚࡍࡿࡇ ࣒ࡢ≉ᛶࢆ᫂ࡽࡍࡿࡇࡀྍ⬟࡛࠶ࡿ 157, 159 ࠋ ὀពࡀᚲせ࡛࠶ࡿࠋ ≉ࠊࣔࣥࢸ࢝ࣝࣟィ⟬ࡣࠊ(1) ┦ᑐᩓಀᩘࢆỴ ័⩦ⓗࠊSc ࡣࣅࣝࢻࢵࣉ࢟ࣕࢵࣉࢆࡅࡓ㟁 ᐃࡍࡿࡇࠊ(2) ᩓಀᩘࡢྛᵓᡂᡂศࢆศᯒࡍࡿ 㞳⟽ࢆ⏝࠸࡚ ᐃࡍࡿሙྜࡀ࠶ࡿࠋࡇࡇ࡛ࠊࣅࣝࢻ ࡇࠊ(3) ᩓಀᩘࡢ ᐃࡢࡓࡵࡢ᪂ࡋ࠸ᡭἲࢆ⪃ ࢵࣉ࢟ࣕࢵࣉࡢ㑅ᢥࡣ㠀ᖖ㔜せ࡛ࠊ࢟ࣕࢵࣉཌ ࡍࡿࡇࠊ࡛⏝࠸ࡽࢀ࡚ࡁࡓ 10, 11, 13 ࠋ࠼ࡤࠊࣔ ࡣ㐣ᑠ࡛࠶ࡿࡼࡾࡣ㐣࡛࠶ࡿ᪉ࡀⰋ࠸ࠋ࢟ࣕࢵࣉ ࣥࢸ࢝ࣝࣟィ⟬ࡣᑠ↷ᑕ㔝࡛ࢥ࣓࣮ࣜࢱ㸦jaw ࡢཌࡉࡀ༑ศ࡞ሙྜࠊ㟁㞳⟽ࡢᛂ⟅ࡣගᏊ࢟ࣕ MLC ࡞㸧ࡽࡢᩓ⥺ࡢᐤࡀ㢧ⴭ࡛࠶ࡿࡇ ࢵࣉࡢ┦స⏝࡛⏕ࡌࡓ㟁Ꮚࡢࡳ࡛ࡣ࡞ࡃࠊࣅ࣮࣒ ࢆ♧ࡋ࡚࠸ࡿ 160-162 ࠋࣔࣥࢸ࢝ࣝࣟἲࡣ ᐃࡢ᳨ド ࡸᑠ↷ᑕ㔝ࡢࢹ࣮ࢱసᡂ࡛⏝࠸ࡽࢀ࡚࠸ࡿ 164 13, 153, 163, ࠋ ୰ࡢΰධ㟁Ꮚࡶྵࡴࡓࡵㄗᕪࡢཎᅉ࡞ࡿࠋTG-74 ࢆཧ↷ࡋࠊ㐺ษ࡞ࢧࢬࡢࣅࣝࢻࢵࣉ࢟ࣕࢵࣉࢆ 㑅ᢥࡍࡿᚲせࡀ࠶ࡿࠋ࢟ࣕࢵࣉࡢཌࡉࡀ༑ศ࡞ሙ ྜࡣ↷ᑕ㔝ࢧࢬᑐࡍࡿ✵୰ฟຊಀᩘ㸦Sc㸧ࡀⴭ IV.C.2. ✵୰ฟຊಀᩘ ࡋࡃኚࡍࡿࡓࡵࠊࡑࡢ⤖ᯝࡋ࡚ࣇࣥࢺ࣒ᩓ Sc ࡣ✵୰ฟຊಀᩘ㸦in-air output factor 165 㸧ࠊࢥ࣓ࣜ ಀᩘ㸦Sp㸧ࡣ↷ᑕ㔝ᑐࡋ࡚ᖹᆠ࡞ࡿࠋᑠ↷ᑕ㔝 ࣮ࢱᩓಀᩘ㸦collimator-scatter factor 㸧ࠊ࣊ࢵࢻᩓ 㸦 4 × 4 cm2㸧࡛ྠࡌ࣑ࢽࣇࣥࢺ࣒ࢆ⏝࠸ࡿሙྜ ಀᩘ㸦head scatter factor166, 167㸧ࡶ࠸ࢃࢀࡿࠋᚋ 2 ࡣ㊥㞳ࢆ㞳ࡋ࡚ ᐃ࡛ࡁࡿࠋࡇࡢሙྜࠊ␗࡞ࡿ SSD ⪅ࡣฟຊಀᩘࡢ 1 せ⣲࡛࠶ࡿࡇࡀᙉㄪࡉࢀࡿሙྜ ࡛ྲྀᚓࡋࡓ 2 ࡘࡢ Sc ࢆ⤫ྜ࡛ࡁࡿࡼ࠺ࠊᘏ㛗㊥㞳 ⏝࠸ࡿࠋTG-74㸦Ref. 20㸧࡛ࡣ✵୰ฟຊಀᩘ Sc ࡢ ࡛ࡶ 10 × 10 cm2 ࡢฟຊಀᩘࢆ ᐃࡍࡿࡇࡀ㔜せ ヲ⣽ࡀ♧ࡉࢀ࡚࠾ࡾࠊ௵ពࡢ↷ᑕ㔝ᇶ‽↷ᑕ㔝ࡢࠊ ࡛࠶ࡿࠋTG-74 ࡛ࡣ࡚ࡢ Sc ࢆྠࡌ SSD ࡛ ᐃࡍ ༢ MU タᐃ್࠶ࡓࡾࡢ✵Ẽ୰࠾ࡅࡿỈࡢ୍ḟ⾪ ࡿࡓࡵࠊ㧗ཎᏊ␒ྕࡢ࣑ࢽࣇࣥࢺ࣒ࡢ⏝ࢆ᥎ዡ ✺࣮࣐࢝; Kp ࡢẚࡋ࡚ᐃ⩏ࡉࢀࡿࠋ ࡋ࡚࠸ࡿࠋ ᐃྍ⬟࡞᭱ᑠ↷ᑕ㔝ࡣࠊ࣑ࢽࣇࣥࢺ 88 Sc K p c; z ref M K p cref ; z ref M ࣒ࡢእ࿘ࡽᑡ࡞ࡃࡶ 1 cm ࡢ⠊ᅖࡀ↷ᑕࡉࢀࡿ , (4) ࡇࡇ࡛ c ࡣ௵ពࡢࢥ࣓࣮ࣜࢱࢭࢵࢺࠊcref ࡣᇶ‽ࡢࢥ 2 ࣓࣮ࣜࢱࢭࢵࢺࢆ♧ࡋࠊ㏻ᖖࡣ 10 × 10 cm ࡛࠶ࡿࠋ ᮲௳࡛࠶ࡿࠋ IV.C.3. ࣇࣥࢺ࣒ᩓಀᩘ ࣇࣥࢺ࣒ᩓಀᩘ㸦Sp㸧ࡣࣇࣥࢺ࣒୰ࡢᇶ‽ ࡉࡽࠊzref ࡣᇶ‽ࡢ⥺※-᳨ฟჾ㛫㊥㞳࡛࠶ࡾࠊ㏻ ῝ dref ࠾ࡅࡿ↷ᑕ㔝ࢧࢬ s ᇶ‽↷ᑕ㔝 sref ࡢ ᖖࡣ 100 cm ࡛࠶ࡿࠋࡲࡓࠊ୍ḟ⾪✺࣮࣐࢝ࡣ⒪ ᩓಀᩘẚࡋ࡚ᐃ⩏ࡉࢀࡿࠋ ࣊ࢵࢻ࡛⏕ࡌࡓ࡚ࡢᩓ⥺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⏝࡛ࡁࡿሙ ྜࠊࢹ࣮ࢱࡢ᳨ドࡀᚲせ࡛࠶ࡿࠋࡇࢀࡣ↷ᑕ㔝῝ ࡇࡇ࡛ SF ࡣࠊྠࡌ↷ᑕ㔝ࢧࢬ῝ࡉ࡛ࠊྠࡌ ࡉࡘ࠸࡚ᩘⅬ࡛☜ㄆࡍࢀࡤⰋࡃࠊCheng ࡽ 175 ࡣ ⨨࠾ࡅࡿࠊ୍ḟ⥺ࡢ⥺㔞㸦Dp㸧ᑐࡍࡿỈ୰ࡢ lower upper ࡢ࢙࢘ࢵࢪಀᩘࡣࡰ୍⮴ࡍࡿࡇ ⥺㔞㸦D㸧ࡢẚ࡛࠶ࡿࠋࡲࡓࠊࣇࣥࢺ࣒ᩓಀᩘ 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 ࢆ ࡓࡣ㠀≀⌮࢙࢘ࢵࢪࡤࢀࠊၟᶆ࡛ࡣࢲࢼ࣑ࢵ ⏝࠸࡚ྲྀᚓࡍࡿࠋ୍ḟ⥺ࡢ྾⥺㔞⾪✺࣮࣐࢝ࡢ ࢡ࢙࢘ࢵࢪࡲࡓࡣࣂ࣮ࢳ࢙ࣕࣝ࢘ࢵࢪࡋ࡚▱ࡽ ẚ ȕp ࢆ⏝࠸࡚ࠊ୍ḟ⥺㔞୍ḟỈ⾪✺࣮࣐࢝ࡢ㛵ಀ ࢀ࡚࠸ࡿࠋࡇࢀࡽࡣ〇㐀ᴗ⪅ࡼࡗ࡚ືసࡀ␗࡞ࡿࠋ ࢆ⾲ࡏࡿ㸦Dp=ȕpKp㸧ࠋᘧ(6)ࡣࠊ୍ḟ⥺ࡢ⥺㔞-࣮࢝ Varian ♫ࡣ࢚ࣥࣁࣥࢫࢻࢲࢼ࣑ࢵࢡ࢙࢘ࢵࢪ ࣐ẚࡀ↷ᑕ㔝ࢧࢬ౫Ꮡࡋ࡞࠸ሙྜ 㸦Enhanced dynamic wedge; EDW㸧ࠊSiemens ♫ࡣࣂ 㹙ȕp(s)=ȕp(sref) 㹛ࠊཝᐦᡂ❧ࡍࡿࠋ ࣮ࢳ࢙ࣕࣝ࢘ࢵࢪ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⏕ࡌࡉࡏࠊ᪉ࡢ Y-jaw ࡣ㟼Ṇࡉࡏ࡚࠸ IV.C.4.a. ≀⌮࢙࢘ࢵࢪ ࡿࠋEDW VW ࡢ࡞㐪࠸ࡣࠊEDW ࡣ jaw ࡢ⛣ື ㏻ᖖࠊ࢙࢘ࢵࢪಀᩘࡣ࢙࢘ࢵࢪゅᗘࠊ῝ࡉࠊගᏊ ࢚ࢿࣝࢠ࣮࠾ࡼࡧ↷ᑕ㔝ࢧࢬ౫Ꮡࡍࡿ 168-173 ࠋ ≀⌮࢙࢘ࢵࢪࡢಀᩘࡣᇶ‽῝㸦10 cm ࡲࡓࡣ dmax㸧ࠊ SSD=100 cm ࠾࠸࡚␗࡞ࡿ↷ᑕ㔝࡛ ᐃࡍࡿࠋຍ ㏿ᗘ⥺㔞⋡ࡀኚࡍࡿࡢᑐࡋࠊVW ࡣ jaw ࡢ⛣ ື㏿ᗘࡀ୍ᐃ࡛ゎᯒ㛵ᩘᚑࡗ࡚⥺㔞⋡ࢆኚࡉ ࡏࡿⅬ࡛࠶ࡿࠋ ࢯࣇࢺ࢙࢘ࢵࢪࡢ࢙࢘ࢵࢪಀᩘࡣ≀⌮࢙࢘ࢵࢪ ㏿ჾࡢ୰ࡣ↷ᑕ㔝࡛࢙࢘ࢵࢪಀᩘࡀ↷ᑕ㔝 ࡢಀᩘࡣࡃ␗࡞ࡿࠋEDW ࡢ࢙࢘ࢵࢪಀᩘࡣ࢜ ᙉࡃᙳ㡪ࡉࢀࡿࡶࡢࡀ࠶ࡾࠊࡑࡢሙྜᗈ⠊ᅖࡢ↷ᑕ ࣮ࣉࣥ↷ᑕ㔝ࡢ୰ᚰ࡛῝ࡉ 10 cm ࡘ࠸࡚ᐃ⩏ࡉࢀࠊ 170, 171, 174 ࠋ ↷ᑕ㔝ࢧࢬ࢙࢘ࢵࢪゅᗘ౫Ꮡࡋࠊ≀⌮࢙࢘ࢵ ࢇࡢ TPS ࡛ࡣࠊࡑࢀࡒࢀࡢ↷ᑕ㔝ࡘ࠸࡚࢙࢘ࢵ ࢪẚ㍑ࡋ࡚ 10%-30%㧗࠸ᩘ್ࢆ♧ࡍࠋ⥺㉁ࡀኚ ࢪಀᩘࢆỴᐃࡍࡿࡇࡀ࡛ࡁࡿࠋ ࡋ࡞࠸ࡓࡵ EDW ࡢ࢙࢘ࢵࢪಀᩘࡣ῝ࡉᙳ㡪ࡉࢀ 㔝⠊ᅖᑐࡋ࡚ ᐃࡍࡿࡁ࡛࠶ࡿ ᳨ฟჾࢆࣅ࣮࣒୰ᚰṇ☜タ⨨ࡍࡿࡇࡀ㔜 ࡞࠸ࡇࡀሗ࿌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ᗘࢇ౫Ꮡࡏࡎࠊ1.0% ± 2%ࡢ⠊ᅖࡢ್ ᗘ㸦90° 270°࡞㸧࡛ㄞࡳ್ࡢ୍⮴ࢆ☜ㄆࡍࡿࠋ ࢆ♧ࡍࠋ࢙࢘ࢵࢪಀᩘࡣࠊ␗࡞ࡿ↷ᑕ㔝ࢧࢬࡘ ᳨ฟჾࡀࣅ࣮࣒୰ᚰ㓄⨨ࡉࢀ࡚࠸ࡿࡇࢆ☜ㄆ ࠸࡚ SSD/SAD=100 cm ࡛࣋ࣥࢲ࣮ࡼࡗ࡚ᣦᐃࡉ ࡋࡓᚋࠊ୍᪉ࡢ࢙࢘ࢵࢪ᪉ྥ 180 ᗘᑐᤄධࡋ ࢀࡓᇶ‽῝㸦10 cm ࡲࡓࡣ dmax㸧࡛ ᐃࡍࡿࠋࡉࡽ ࡓ࢙࢘ࢵࢪ᪉ྥ࡛ ᐃࡍࡿࠋ࢙࢘ࢵࢪಀᩘࡣ୍ᐃࡢ ࠊ࢙࢘ࢵࢪಀᩘࡣᅛᐃ jaw ࡢ⨨ࡼࡾ㥑ື jaw ࡢ ࢥ࣓࣮ࣜࢱゅᗘ࡛ᚓࡓ 2 ࡘࡢ࢙࢘ࢵࢪ᪉ྥࡢㄞࡳ್ ࢧࢬ౫Ꮡࡍࡿࡓࡵࠊ㛗᪉ᙧ↷ᑕ㔝ࡢ࢙࢘ࢵࢪಀ ࡢᖹᆒࢆ࣮࢜ࣉࣥ↷ᑕ㔝ࡢㄞࡳ್࡛㝖ࡋ࡚ᚓࡿࠋ࢘ ᩘࢆ㏣ຍࡋ࡚ ᐃࡍࡁ࡛࠶ࡿࠋࡋ࡚ࠊVarian ࢙ࢵࢪಀᩘࡣྲྀᚓࡍࡿ῝ࡉࡼࡗ࡚㢧ⴭ␗࡞ࡿ ♫ࡢ EDW ࡢ 10 × 20 cm2 ࡢ࢙࢘ࢵࢪಀᩘࡣ 10 × 10 ሙྜࡀ࠶ࡿࠋᇶᮏⓗࠊ࢙࢘ࢵࢪಀᩘࡢ ᐃ῝ࡣ TPS cm2 ࡢ࢙࢘ࢵࢪಀᩘ㠀ᖖ㏆࠸್ࢆ♧ࡋࠊࡇࢀࡣ ࡼࡗ࡚ᣦᐃࡉࢀ࡚࠸ࡿࠋࡋࡋࠊᡭィ⟬⏝࣮࢜ ≀⌮࢙࢘ࢵࢪ࡛ࡣ⏕ࡌ࡞࠸⌧㇟࡛࠶ࡿࠋ ࣉࣥ↷ᑕ㔝࢙࢘ࢵࢪ↷ᑕ㔝ࡢ PDD ⾲ࡸ TMR ⾲ࢆ ูࠎ⏝࠸ࡿሙྜࠊࣅ࣮࣒ࣁ࣮ࢻࢽࣥࢢ⿵ṇࢆ 2 㔜 ⾜ࢃ࡞࠸ࡓࡵ࢙࢘ࢵࢪಀᩘࡣ dmax ࡛ྲྀᚓࡍࡿ᪉ࡀ 㐺ษ࡛࠶ࡿࠋVarian ♫ࡢ lower upper ࢙࢘ࢵࢪ࡞ 44 IV.C.4.c. ࣘࢽࣂ࣮ࢧ࢙ࣝ࢘ࢵࢪ Elekta ♫ࡢࣜࢽࢵࢡ࡛ࡣࠊ␗࡞ࡿ࢙࢘ࢵࢪゅᗘ ࢆ⏕ᡂࡍࡿࡓࡵࠊ࣮࢜ࣉࣥ↷ᑕ㔝ෆⶶᘧࡢ 60° ≀ V. 電子線 Jpn. J. Med. Phys. Vol. 33 No. 1 (2013) ⌮࢙࢘ࢵࢪ↷ᑕ㔝ࢆࢯࣇࢺ࢙࢘ࡼࡿไᚚ࡛ྜ ࡁ࡛࠶ࡿࠋฟຊಀᩘࡣ᳨ฟჾࡢタ⨨⢭ᗘᙉࡃᙳ ᡂࡍࡿᡭἲࢆ᥇⏝ࡋ࡚࠸ࡿࠋ࢙࢘ࢵࢪࡣ࣮ࣔࢱ㥑ື 㡪ࡉࢀࡿࡓࡵࠊタ⨨⨨ࡢ᳨ドࡣ㔜せ࡛࠶ࡿ 151,202ࠋ ࡛↷ᑕ㔝ෆฟࡋධࢀࡉࢀࡿࠋࡇࡢࢱࣉࡢ࢙࢘ࢵ ࡇࢀࡣ xy ୧᪉ྥ࡛ࢫ࢟ࣕࣥࡋࠊ್᭱ࢆ♧ࡍࡇ ࢪࢩࢫࢸ࣒ࡣෆ㒊࢙࢘ࢵࢪࡲࡓࡣࣘࢽࣂ࣮ࢧࣝ࢘ ࢆ☜ㄆࡍࡿ᪉ἲ࡛⾜࠺ࠋ㏆ᖺࠊࡼࡾ⢭ᗘࡢ㧗࠸᪉ἲ ࢙ࢵࢪࡋ࡚▱ࡽࢀ࡚࠸ࡿࠋ࢙࢘ࢵࢪಀᩘࡣ TPS ࡛ ࡀ Li ࡽ 203 ࡼࡗ࡚ᥦࡉࢀ࡚࠸ࡿࠋᑠ↷ᑕ㔝࡛ࡣ ᚲせ࡞ࡿᵝࠎ࡞↷ᑕ㔝ࢧࢬ῝ࡉ࡛ྲྀᚓࡍࡿ ↷ᑕ㔝ࢧࢬࡢഹ࡞ㄗᕪࡼࡗ࡚㢧ⴭฟຊࡀ ᚲせࡀ࠶ࡾࠊከࡃࡢᩥ⊩࡛♧ࡉࢀ࡚࠸ࡿ 181-184 ࠋ ኚࡍࡿࡓࡵࠊᐇ㝿ࡢ↷ᑕ㔝ࢧࢬࡶ᳨ドࡍࡿᚲせ ࡀ࠶ࡿࠋࡋࡋࠊഃ᪉㟁Ꮚᖹ⾮ࡀᡂ❧ࡋ࡞࠸᮲௳࡛ IV.C.5. ࢺࣞಀᩘ ࡣṇ☜࡞↷ᑕ㔝ࢧࢬࡀᚓࡽࢀ࡞࠸ሙྜࡀ࠶ࡿࠋ≉ ࣈࣟࢵࢡࢺࣞࠊMLCࠊjaw ࡢ㏱㐣ಀᩘࡣỈ୰ࡢ ࠊ㟁Ꮚᖹ⾮ᡂ❧᮲௳ẚ㍑ࡋ್࡚᭱ࡀ㐣ᑠホ౯ ᇶ‽῝㸦10 cm ࡲࡓࡣ dmax㸧࡛ ᐃࡉࢀࠊ࣮࢜ࣉࣥ ࡉࢀࡓሙྜࠊ್༙㸦half-maximum㸧ࡀప⥺㔞ࣞ࣋ࣝ ↷ᑕ㔝ᑐࡍࡿࣈࣟࢵࢡࢺࣞࠊMLC ࠾ࡼࡧ jaw ┤ ࡼࡾࢩࣇࢺࡍࡿ㸦ࡘࡲࡾࠊ⥺㔞ࣉࣟࣇࣝࡢእ ୗ࡛ࡢㄞࡳ್ࡢẚ࡛ᐃ⩏ࡉࢀࡿࠋMLC ࡸ jaw ࡢ㏱㐣 ഃࢩࣇࢺࡍࡿ㸧ࡇࡼࡗ࡚↷ᑕ㔝ࢧࢬࢆ㐣 ࡣ㠀ᖖᑠࡉ࠸ࡓࡵࠊ㟁ィ/᳨ฟჾࢩࢫࢸ࣒ࡢ┤⥺ ホ౯ࡍࡿࡇࡀ࠶ࡾࠊὀពࢆせࡍࡿࠋࡲࡓࠊග↷ᑕ ࣞࣥࢪྵࡲࢀࠊ⤫ィⓗ☜ࡉࢆ㝖࡛ࡁࡿࡼ࠺ 㔝ࢥ࣓࣮ࣜࢱ⛣ື⨨ࢆࡑࢀࡒࢀㄪᩚࡍࡿࡇ MU ್ࡣ༑ศࡁࡃタᐃࡍࡿᚲせࡀ࠶ࡿࠋࢺࣞ ࡛ࠊ↷ᑕ㔝➃ࡢ⨨ࢆ⟶⌮ࡍࡿᚲせࡀ࠶ࡿࠋ ㏱㐣ಀᩘࡣỈࣇࣥࢺ࣒࡞ࡋ࡛ࡶ ᐃࡍࡿࡇࡀ V. 㟁Ꮚ⥺ ࡛ࡁࡿࠋ V.A. 㟁Ꮚ⥺ࢫ࢟ࣕࣥࢹ࣮ࢱ ᐃ IV.C.6. ᑠ↷ᑕ㔝࡛ࡢ⪃៖ V.A.1. ῝㒊⥺㔞 ୍⯡ⓗ࡞ᨺᑕ⥺⒪࡛⏝࠸ࡽࢀࡿ↷ᑕ㔝ࡣ 4 × 4 2 2 Followill ࡽࡼࡗ࡚♧ࡉࢀ࡚࠸ࡿࡼ࠺ࠊ㟁Ꮚ⥺ cm ࡽ 40 × 40 cm ࡛࠶ࡿࠋࡋࡋࠊIMRTࠊSRSࠊ ࡢ῝㒊⥺㔞≉ᛶࡣࠊタࡸ⨨ẖࡁࡃ␗࡞ࡿ 204ࠋ CyberKnifeࠊGamma Knife ࡞㧗⢭ᗘ࡛≉Ṧ࡞ᨺᑕ ࡼࡗ࡚ࢥ࣑ࢵࢩࣙࢽࣥࢢ࡛ࡣࠊ⨨ẖࣅ࣮࣒ࢹ࣮ ⥺⒪࡛ࡣᩘ mm ࡢᴟ➃ᑠࡉ࠸↷ᑕ㔝ࢆ⏝ࡍࡿࠋ ࢱࢆ ᐃࡍࡿࡇࡀ᥎ዡࡉࢀࡿࠋ㟁Ꮚ⥺ࡢࣅ࣮࣒ࢹ ᑠ↷ᑕ㔝ࡢ⥺㔞 ᐃ㛵ࡍࡿၥ㢟Ⅼࡢヲ⣽࡞ࣜࢫ ࣮ࢱ ᐃࡣࠊࢲ࣮࢜ࢻ᳨ฟჾࠊᖹ⾜ᖹᯈᙧ㟁㞳 ࢺᑗ᮶ࡢືྥࡣ Das ࡽ 152 ࡼࡗ࡚㆟ㄽࡉࢀ࡚࠸ ⟽ࠊᣦ㢌ᙧ㟁㞳⟽ࡸࣇ࣒ࣝ࡞ࡀ⏝࠸ࡽࢀࡿࠋ ࡿࠋ≉ࠊഃ᪉㟁Ꮚᖹ⾮ࡢḞዴ ࢧࢬ 186 ࠊ༙ᙳ㒊᳨ฟჾ 152 ࠊ࢚ࢿࣝࢠ࣮ࢫ࣌ࢡࢺࣝࡢኚక࠺⥺㔞 ᐃ㛵ಀࡍࡿࣃ࣓࣮ࣛࢱࡸ㜼Ṇ⬟ẚࡢኚ 187-189 163, ࡞ࠊᑠ↷ᑕ㔝ࡢ⥺㔞 ᐃࡣከࡃࡢ▱㆑ࢆᚲせ Ⰻ㉁࡞PDDࢆྲྀᚓࡍࡿࡣࠊṇ☜࡞ 0 mm῝ࡢỴ ᐃࡀ㔜せ࡛࠶ࡿࠋᣦ㢌ᙧ㟁㞳⟽ࡢᐇຠ୰ᚰࡣࠊᗄఱ Ꮫⓗ୰ᚰࡽ 0.5rcyl⥺※ഃ࡛࠶ࡿ 56, 145 ヂ⪅ὀ 4 ࠋ 6 MeV࡞ࡢప࢚ࢿࣝࢠ࣮㟁Ꮚ⥺ࡢ῝㒊㟁㞳㔞᭤⥺ ࡍࡿࠋᑠ↷ᑕ㔝ࡢ⥺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 ࠸PDI᭤⥺ࡣࠊ〇㐀ᴗ⪅ࢃࡽࡎ 6 MeV࡛ࡣᖹ ࠋ ᑠᆺ᳨ฟჾ࠾࠸࡚ࡶࠊ࢚ࢿࣝࢠ࣮ࠊ⥺㔞࠾ࡼࡧ ᆒ 1.1 s 0.2 cmࡢ᭱῝㸦dmax㸧࡞ࡿࡣࡎ࡛࠶ࡿࠋ ⥺㔞⋡౫Ꮡᛶࡀᑠࡉ࠸᳨ฟჾࡀᮃࡲࡋ࠸ࠋ࣐ࢡࣟ ࡇࡢ㟁㞳㔞ࡼࡿdmaxࡀ 0.2 cm௨ୖ␗࡞ࡿࠊ0 mm 3 ᆺ㟁㞳⟽㸦⣙ 0.01 cm 㸧ࡣᑠ↷ᑕ㔝ࡢ⥺㔞 ᐃ᭷ ῝ࡢタᐃࡀㄗࡗ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿࡓࡵࠊ㟁㞳⟽ ຠ࡛࠶ࡿࡀࠊಙྕᑐࡍࡿࣀࢬࡢẚ⋡ࡀቑࡍࡿ Ỉ㠃ࡢタ⨨ࢆ☜ㄆࡍࡿᚲせࡀ࠶ࡿࠋ ࡓࡵホ౯ࡀᚲせ࡛࠶ࡿࠋࡉࡽࠊSauer ࡽ ࡸ PDI ᭤⥺ࡣ࢚ࢿࣝࢠ࣮ࡢࣜࣇࣞࣥࢫ࡞ࡿࢥ ࡀ♧ࡍࡼ࠺ࠊࡇࢀࡽࡢ᳨ฟჾ࡛ࡣ ࣮ࣥ㸦10 × 10 cm2 ࡸ 15 × 15 cm2㸧࡛ࠊᐇ⏝㣕⛬㸦Rp㸧 ᨐಀᩘࡘ࠸࡚⪃៖ࡍࡿᚲせࡀ࠶ࡿࠋ↷ᑕ㔝୰ᚰ + 10 cm ࡢ῝ࡉࡲ࡛ 0.1 cm 㛫㝸࡛ ᐃࡍࡿࡁ࡛࠶ Francescon ࡽ 153 164 ࡛ࡢࢫ࢟ࣕࣥ ᐃ࡛ࠊ᳨ฟჾ┤ᚄࡢ⠊ᅖ࡛⥺㔞ࡀ 1%௨ୖኚࡍࡿሙྜࡣࠊࡼࡾᑠࡉ࠸᳨ฟჾኚ᭦ࡍ ヂ⪅ὀ4 rcyl 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 ࡀࣜࣇࣞࣥࢫࡢࢥ࣮ࣥࡋ࡚ ⏝ࡉࢀࡿࠋࣜࣇࣞࣥࢫ࡞ࡿࢥ࣮ࣥࢆ⏝ࡋࡓ ࢚ࢿࣝࢠ࣮ࡢ PDI ᭤⥺ࡽࠊࣉࣟࣇࣝࢫ࢟ࣕ ࣥࢆࡍࡿ῝ᗘ dmax, d90, d80, d70, d60, d50, d40, d30, d20, ࠾ ࡼࡧ Rp ࡀỴᐃࡉࢀࡿࠋཝᐦゝ࠼ࡤࠊRp ࡣࣅ࣮࣒ ࢆ⿵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ࡣࢃࡎ࡛࠶ࡿࠋ 㟁㞳⟽ࡼࡿỈ୰࡛ࡢ PDI ᭤⥺ࡣࠊ㐺ษ࡞ኚ⿵ ṇಀᩘỈ㸭✵Ẽࡢᖹᆒไ㝈㉁㔞⾪✺㜼Ṇ⬟ẚࢆ FIG. 12. Effect of water ripple on low energy electron beam depth ⏝ࡋ࡚ࠊ῝㒊⥺㔞᭤⥺ኚࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋ dose. ࡰ࡚ࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࠊ㟁㞳㔞ࢆ⥺㔞 ኚࡍࡿࡓࡵࡢࣉࣟࢢ࣒ࣛࡀᐇࡉࢀ࡚࠸ࡿࠋࡇ ࢀࡽࢆ⏝ࡍࡿሙྜࡣࠊࣜࣇࣞࣥࢫࢹ࣮ࢱࢆᇶࠊ ືᨺᑕ⥺ᡂศࡢホ౯ࡣṇ☜࡛ࡣ࡞࠸ヂ⪅ὀ 6ࠋ ྛ῝ࡉ࡛ኚ⢭ᗘࢆ᳨ドࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ 22,56,88,205 V.A.2. ࣉࣟࣇࣝ 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ࣉࣟࣇࣝࢆᚲ ࡕࡼࡿPDD᭤⥺ࡢᙳ㡪ࢆ♧ࡍࠋࡇࡢࡼ࠺࡞ሙྜ せࡍࡿࠋࡓࡔࡋࠊ⥺㔞ࣉࣟࣇࣝࢆྲྀᚓࡋ࡞ࡅ ࡣࠊࢫ࢟ࣕࣥࣃ࣓࣮ࣛࢱࡢタᐃࡀᚲせ࡛࠶ࡿࠋ㟁 ࢀࡤ࡞ࡽ࡞࠸῝ࡉࡣࠊTPS ࡢᵝࡼࡗ࡚␗࡞ࡿࠋ Ꮚ⥺ࡢࢫ࡛࢟ࣕࣥ⌮ⓗ࡞ ᐃჾࡣࠊ✵㛫ศゎ⬟ࡢ ≉ప࢚ࢿࣝࢠ࣮㟁Ꮚ⥺࡛ࡣࠊdmax ࡼࡾ῝࠸⨨࡛ 㧗࠸ᑠᆺࡢ㟁Ꮚ⥺⏝ࢲ࣮࢜ࢻ᳨ฟჾ࡛࠶ࡿࠋࡑࡢ ࡢࣉࣟࣇࣝࡢ ᐃὀពࡀᚲせ࡞ࡿࠋࣉࣟࣇ ⌮⏤ࡣࠊ(1) 㟁㞳㔞ࡽ⥺㔞ኚࡍࡿᚲせࡀ↓࠸ ヂ ࣝᙧ≧ࡀ㢧ⴭ㠀ᑐ⛠࡛࠶ࢀࡤࠊࢫ࢟ࣕࢽࣥࢢ ⪅ὀ 5 ࠋ(2) ᐃⅬࡢኚࢆ⾜࠺ᚲせࡀ↓࠸ࠋࡓࡔࡋࠊ ࢱࣥࢡࡸࢫ࣮࣒࢟ࣕࣥࡢỈᖹࠊ࢞ࣥࢺࣜゅᗘ࡞ 㜵Ỉࢥ࣮ࢸࣥࢢ㸦㏻ᖖ~0.2 mm㸧ࡀࡉࢀ࡚࠸ࡿ ࡢ☜ㄆࡀᚲせ࡛࠶ࡿࠋప࢚ࢿࣝࢠ࣮㟁Ꮚ⥺ࡢ῝࠸ ࢲ࣮࢜ࢻ᳨ฟჾࡣᙜ࡚ࡣࡲࡽ࡞࠸ྍ⬟ᛶࡀ࠶ ⨨࡛ࡢ⥺㔞ࣉࣟࣇࣝࡣࠊ࡛ࡇࡰࡇࡋࡓᙧ≧ ࡿࠋ ࡞ࡿࡇࡀ࠶ࡿࠋ㟁ィࡢࢤࣥࠊࣜࣇࣞࣥࢫ ࠸ࡃࡘࡢ TPS ࡛ࡣࠊไືᨺᑕ⥺ᡂศࡢሗࡀ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࠸ࡃࡘࡢせᅉࢆ᳨ウࡍࡁ࡛࠶ ⏕ࡍࡿࠋࡑࢀࡒࢀࡢᙳ㡪ࢆ㝖ཤࡍࡿࡇ࡛ࠊไືᨺ ࡿࠋ⮫ᗋ࣮ࣔࢻ᳨࡛ドࡍࡿᚲせࡀ࠶ࡿࡀࠊࣜࢽࢵ ᑕ⥺ࡢྜࢆṇ☜ྲྀᚓ࡛ࡁࡿ᪉ἲࢆ Zhu ࡽࡀሗ࿌ ࢡࡼࡗ࡚ࡣࠊࢧ࣮࣎ไᚚࢆ࢜ࣇࡍࡿࡇࡼࡗ ࡋ࡚࠸ࡿ 206 ࠋ 㟁Ꮚ⥺⏝ࢲ࣮࢜ࢻ᳨ฟჾ࡛࢝ࢵࢺ࢘ࢺ↷ᑕ ࡚ࣉࣟࣇࣝࢆᨵၿࡍࡿࡇࡀ࡛ࡁࡿࡶࡢࡀ࠶ ࡿࠋࡲࡓࠊ≉ᐃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡛ࡣࠊࣉࣟ 㔝ࡼࡿ PDD ࢆ ᐃࡍࡿሙྜࠊࢲ࣮࢜ࢻගᏊ ࣇࣝࡣ⮬ືࢤࣥタᐃࣂࢵࢡࢢࣛ࢘ࣥࢻࢆ ⥺ࡢ┦స⏝࢚ࢿࣝࢠ࣮౫Ꮡᛶࡀ࠶ࡿࡓࡵࠊไ ㄪᩚࡍࡿࡇࡼࡗ࡚ᨵၿࡉࢀࡿྍ⬟ᛶࡶ࠶ࡿࠋ Fig. 9 ࠊ㟁Ꮚ⥺ࣉࣟࣇࣝࡢࢫ࢟ࣕࣥ㏿ᗘࡼ ヂ⪅ὀ5 Ỉ㸭ࢩࣜࢥࣥࡢᖹᆒไ㝈㉁㔞⾪✺㜼Ṇ⬟ẚࡀࠊ ⏝ࡍࡿ࢚ࢿࣝࢠ࣮ࢃࡓࡾࡁࡃኚࡋ࡞࠸ࡓ ࡵࠋ 46 ヂ⪅ὀ6 ṇ☜࡞ไືᨺᑕ⥺ᡂศࢆྲྀᚓࡍࡿࡓࡵࡣࠊ 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࡞ࣉࣟࣇࣝࢹ࣮ࢱࢆྲྀᚓࡍ SSD ᩚᙧ࡞࢝ࢵࢺ࢘ࢺࡢ⥺㔞/MU ࢆண ࡍ ࡿࡓࡵࡣࠊࢫ࢟ࣕࣥ㏿ᗘࡢపῶࡸࢧࣥࣉࣜࣥࢢ ࡿࡓࡵࠊࢡ࣮ࣛࢡࢯࣥἲ㢮ఝࡋࡓᡪᙧ✚ศἲࢆ 㛫ࡢᘏ㛗ࡀᚲせ࡞ࡿࠋ ⏝ࡍࡿࡇࡀሗ࿌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ᩓࡉࢀࡿࡓࡵࠊཝ ௵ពࡢࢥ࣮ࣥࡢฟຊಀᩘࡣࠊᇶ‽ࢧࢬࡢࢥ࣮ࣥ 2 2 ᐦ࡞㊥㞳ࡢ㏫๎ᚑࢃ࡞࠸ࠋ≉ࠊࢥ࣓࣮ࣜࢱ 㸦㏻ᖖࡣ 10 × 10 cm ࡲࡓࡣ 15 × 15 cm 㸧ࡢ᭱῝ ࢥ࣮ࣥࡽࡢᩓ㟁Ꮚ⥺ࡣࠊ༢୍ࡢ⥺※ࡋ࡚ࡢ ྾⥺㔞㸦Ddmax㸧ᑐࡍࡿ௵ពࡢࢥ࣮ࣥࡢ Ddmax ࡢ ≉ᛶᚑࢃ࡞࠸ 210ࠋࡇࡢ≉ᛶࢆᢕᥱࡍࡿࡓࡵࠊ㏫ ẚ࡛࠶ࡿࠋ25 × 25 cm2 ࡢࢥ࣮ࣥಀᩘࡣࠊ30 × 30 cm2 ๎ࡀ㐺⏝࡛ࡁࡿࡼ࠺࡞௬ⓗ࡞⥺※⨨ࢆỴ ௨ୖࡢỈࣇࣥࢺ࣒ᅛయࣇࣥࢺ࣒࡛ ᐃࡍ ᐃࡍࡿ᪉ἲࡀ࠶ࡿ 56ࠋ ࡁ࡛࠶ࡿࠋྠ୍ࡢ〇㐀ᴗ⪅ࡼࡿྠࡌࣔࢹࣝࡢ⒪ ࣂ࣮ࢳࣕࣝࢯ࣮ࢫ㸦௬⥺※㸧ࢆ᥎ᐃࡍࡿ᪉ἲ ⨨㸦࠼ࡤ 2 ྎࡢ 21EX㸧࡛࠶ࡗ࡚ࡶࠊࢥ࣮ࣥಀ ࡋ࡚ࢠࣕࢵࣉἲVTFἲ 205, 211 ࡀᥦࡉࢀ࡚࠸ࡿࠋ ᩘࡣ␗࡞ࡿࡇࡀ࠶ࡿࡀࠊࡑࡢᕪࡣࡁࡃࡣ࡞࠸ Khan ࡼࡿࢠࣕࢵࣉἲࡶࡋࡃࡣᐇຠ SSD ἲࡣࠊྛ 㸦2%⛬ᗘ㸧ࡔࢁ࠺ࠋྠ୍ࣔࢹࣝࡢ␗࡞ࡿ⨨ࡢࢥ࣮ ㊥㞳࠾ࡅࡿ㟁Ꮚ⥺⥺㔞ࢆ㏫๎ࡼࡗ࡚ィ⟬ ࣥಀᩘࢆὶ⏝ࡍࡿሙྜࡣࠊ࠶ࡽࡌࡵ࡚ࡢ࢚ࢿࣝ ࡇࡢᡭἲࡣẚ㍑ⓗ༢⣧࡛ࠊ ࡍࡿࡓࡵࡢᡭἲ࡛࠶ࡿ 88ࠋ ࢠ࣮ࢥ࣮࡛ࣥࢥ࣮ࣥಀᩘࢆ ᐃࡋ࡚ࠊ☜ㄆࡍࡿࡇ ⨨ࠊ↷ᑕ㔝ࢧࢬࠊ࢚ࢿࣝࢠ࣮౫Ꮡࡍࡿᐇຠ ࢆ᥎ዡࡍࡿࠋ SSD ࡢỴᐃࡀᚲせ࡞ࡿࠋ㟁Ꮚ⥺ࢥ࣮ࣥỈ㠃ࡢࢠ ࣕࢵࣉࢆኚࡉࡏ࡞ࡀࡽ dmax ࡛ ᐃࢆ⾜࠸ࠊࢠࣕࢵ V.B.2. ࢝ࢵࢺ࢘ࢺಀᩘ ࣉᑐࡍࡿ I0/I ࡢᖹ᪉᰿ࢆࣉࣟࢵࢺࡍࡿࠊࡑࡢഴ ࢝ࢵࢺ࢘ࢺಀᩘࡣࠊྛࢥ࣮࡛ࣥࡢ࢝ࢵࢺ࢘ࢺ ࡢ᭷↓ࡼࡿࠊࡑࢀࡒࢀࡢdmax࡛ࡢ⥺㔞ẚ࡛࠶ࡿ ヂ⪅ ࡁࡼࡗ࡚ᐇຠ SSD ࡀỴᐃࡉࢀࡿࠋICRU-35 van Battum ࡽࡼࡗ࡚㏙ࡽࢀ࡚࠸ࡿ Sigma-theta-F ὀ7 㸦VTF㸧ࡣࠊ᭱⤊ⓗ࡞↷ᑕ㔝㝈ᐃჾࡢ࠶ࡿᖹ㠃࡛ࡢࠊ ẖࡢ⾲ࢆ‽ഛࡍࡿⰋ࠸ࠋ࢝ࢵࢺ࢘ࢺࡢᙧ≧ࡣ㛗 ࢞࢘ࢫศᕸࡋ࡚ぢ✚ࡽࢀࡓゅᗘศᕸࡢᖹᆒ ᪉ᙧࠊࠊᴃࡸṇ᪉ᙧ࡞ࡀ࠶ࡿࠋ࢝ࢵࢺ࢘ࢺ ್ࡢᖹ᪉᰿㸦root-mean-square㸧࡛࠶ࡿ 205, 211ࠋࡇࡢ ಀᩘࡣࠊ㏻ᖖࡑࢀࡽࡢ➼౯ṇ᪉ᙧ࡛⾲ࡋ࡚ࡲࡵ ᪉ἲࡣࠊ᭱ࢧࢬࡢࢥ࣮ࣥࢆ⏝࠸࡚ࠊ␗࡞ࡿ ࡽࢀࡿࠋ㟁Ꮚ⥺ࡢ➼౯ṇ᪉ᙧฟຊ⥺㔞ࡢ⟬ฟࡣࠊ ࢯࢭࣥࢱ᳨ฟჾ㛫㊥㞳࡛ࠊࣇ࣒ࣝࡸ 217 ࢲ࣮࢜ ࡢᩥ⊩࡛ヲ⣽㏙ࡽࢀ࡚࠸ࡿ 22,56,205,207ࠋ ࢻ 34 ࡛ ᐃࡉࢀࡓ✵୰࡛ࡢ༙ᙳ㒊ศ㸦20-80%㸧ࡢࣉ 1 × 2 cm2ࠊ2 × 2 cm2 ࡞ࡢ㠀ᖖᑠࡉ࠸࢝ࢵࢺ ࣟࣇࣝࢆᚲせࡍࡿࠋ ࠋ㢖⦾⏝࠸ࡿ࢝ࢵࢺ࢘ࢺಀᩘࡣࠊ࢚ࢿࣝࢠ࣮ ࢘ࢺࡢ dmax ࡣࠊࡁ࡞࢝ࢵࢺ࢘ࢺ␗࡞ࡿࡇࡀ ࠶ࡿࡓࡵࠊྛ࢝ࢵࢺ࢘ࢺ࡛ ᐃࡼࡾỴᐃࡍࡿᚲ V.B.4. ࣔࣥࢸ࣮࢝ࣝࣟ࣋ࢫࡢ⥺㔞ィ⟬ࡢࡓࡵࡢࢹ せࡀ࠶ࡿࠋࡇࡢሙྜࠊ㟁㞳⟽ࡢ㑅ᢥタ⨨⨨⢭ᗘ ࣮ࢱ ࡀࠊ㠀ᖖ㔜せ࡞ࡿࠋ ࣔࣥࢸ࢝ࣝࣟࢩ࣑࣮ࣗࣞࢩࣙࣥࡼࡿ㟁Ꮚ⥺ࣅ SSD㸻110 cm ࡢࡼ࠺㊥㞳ࢆᘏ㛗ࡋࡓ࢝ࢵࢺ ࣮࣒ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ㛵ࡍࡿ◊✲ࡀᗈࡃ⾜ࢃ ࢘ࢺಀᩘࡣࠊ(1) ᐃࢆ⾜࠺ࠊࡲࡓࡣࠊ(2) ࢥ࣑ࢵࢩ ࢀ࡚࠸ࡿ 13, 157, 210, 218-221ࠋࡑࢀࡽࡣࠊࣔࣥࢸ࢝ࣝࣟἲ ࣙࢽࣥࢢࡉࢀࡓ 100 cm SSD ࡛ࡢ࢝ࢵࢺ࢘ࢺಀᩘ ࡼࡗ࡚ࣅ࣮࣒ࢹ࣮ࢱࢆసᡂ࡛ࡁࡿྍ⬟ᛶࢆ᫂ࡽ ࡽࠊ௬ SSD ࢆ⏝࠸ࡿࠊࡢ 2 ࡘࡢ᪉ἲ࡛⟬ฟ࡛ࡁ ࡋࡓࠋPhase-space ࢹ࣮ࢱ㸦ྛ⢏Ꮚࡢ㟁Ⲵࠊ⨨ࠊ ࡿࠋ2 ࡘࡢ᪉ἲ㸦 ᐃ௬ SSD ࡼࡿ⟬ฟ㸧㛫ࡢ ᪉ྥࠊ࢚ࢿࣝࢠ࣮ࣄࢫࢺ࣭ࣜࢱࢢࡢࢹ࣮ࢱ㸧ࡣࠊ ┦㐪ࡣ 2%௨ෆ࡛࠶ࡿࠋs2%ࡢ⥺㔞⢭ᗘ࡛ᵝࠎ࡞ ࣔࣥࢸ࣮࢝ࣝࣟ࣋ࢫࡢ⒪ィ⏬ᚲせࡉࢀࡿࠋࣔ ࣥࢸ࢝ࣝࣟィ⟬ࡢጇᙜᛶࢆ᳨ドࡍࡿࡓࡵࠊࣔࣥࢸ࢝ ヂ⪅ὀ7 ࢝ࢵࢺ࢘ࢺࡣ㟁Ꮚ⥺ࢥ࣮ࣥࡢඛ➃㒊タ ⨨ࡍࡿࣈࣟࢵࢡࢆᣦࡍࠋ ࣝࣟࢩ࣑࣮ࣗࣞࢩࣙࣥ ᐃࢆ⤌ࡳྜࢃࡏࡿᚲ せࡀ࠶ࡿࠋᚑ᮶ࡢ ᐃࢹ࣮ࢱ㸦࠼ࡤࠊPDDࠊࣉࣟ 47 医学物理 第 33 巻 第 1 号 VI. ビームデータの加工 ࣇࣝࠊฟຊಀᩘࠊ⤯ᑐ⥺㔞㸧ຍ࠼࡚ࠊࣔࣥࢸ ࣮࢝ࣝࣟ࣋ࢫࡢࢩࢫࢸ࣒ࡢࡓࡵࡢࢥ࣑ࢵࢩࣙ ࢽࣥࢢሗࡀᚲせ࡞ࡇࡀ࠶ࡿ 9, 13, 220-226ࠋ 㟁Ꮚ⥺ࡢࢥ࣑ࢵࢩࣙࢽࣥࢢ࡛ࠊࣔࣥࢸ࢝ࣝࣟィ⟬ ࡼࡗ࡚ᚓࡓ࢚ࢿࣝࢠ࣮ࢫ࣌ࢡࢺࣝ⥺㔞ィ⟬ࢆ ᐇドࡍࡿࡓࡵࡢࢹ࣮ࢱࡀᚲせ࡞ࡿࡇࡀ࠶ࡿࠋࡑ ࢀࡒࢀࡢࣔࣥࢸ࣭࢝ࣝࣟࣝࢦࣜࢬ࣒ࠊ࠼ࡤ࣎ࢡ ࢭ࣭ࣝࣔࣥࢸ࢝ࣝࣟ 222 ࡲࡓࡣ࣐ࢡࣟࣔࣥࢸ࢝ࣝࣟ 223, 224 ࡛ࠊࢥ࣑ࢵࢩࣙࢽࣥࢢᚲせ࡞ࢹ࣮ࢱࢭࢵࢺ ࡀ␗࡞ࡿࡇࡀ࠶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࠾ࡼࡧࣀࣥࢫ࢟ࣕࣥࡢࣅ࣮࣒ࢹ࣮ࢱྲྀ ᚓᚋࠊTPS ࢹ࣮ࢱࢆⓏ㘓ࡍࡿ๓ຍᕤࡀᚲせ࡞ࡇ ࡀ࠶ࡿࠋከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒࡛ࡣࠊࣉࣟ ࣇࣝࡢࢭࣥࢱࣜࣥࢢࠊࢫ࣒࣮ࢪࣥࢢࡸᑐ⛠࡞ ࠊከᩘࡢࢶ࣮ࣝࡀ⏝࡛ࡁࡿࠋຍᕤࡢ⛬ᗘࡣࠊࢫ ࢟ࣕࢼࡢࢱࣉ㸦ࢲ࣮࢜ࢻࡸ㐃⥆ⓗ࡞⥺㔞⋡࣮ࣔ ࢻ࡛ࡢࢫ࢟ࣕࣥ㸧 ࠊࢭࢵࢺࢵࣉ⢭ᗘ࠾ࡼࡧ⨨⮬ యࡢ≉ᛶ࡞౫Ꮡࡍࡿࠋ VI.B. ࢫ࣒࣮ࢪࣥࢢ࣭࣑࣮ࣛࣜࣥࢢ࠾ࡼࡧࢧ࣐ࣛ ࢪࣥࢢ ࡍ࡚ࡢ ᐃࢹ࣮ࢱࡣࠊࢩࢫࢸ࣒౫Ꮡࡋࡓࣀ ࢬࢆྵࡴࠋࢫ࣒࣮ࢪࣥࢢࣇࣝࢱࣜࣥࢢ᧯సࡣࠊ ࣀࢬࢆ㝖ཤࡋࠊ┿ࡢࢹ࣮ࢱࢆྲྀࡾฟࡍࡇᙺ❧ ࡘࠋࡇࢀࡣపᇦ㏻㐣ࣇࣝࢱ࡛ࡶ࠶ࡾࠊ㠀㐃⥆ⓗࠊ 㗦ᩄࠊᲲ≧࡞ࡢ㧗࿘Ἴᡂศࢆ㝖ཤࡍࡿࠋࢫ࣒࣮ࢪ ࣥࢢἲࡣࠊ᭱ᑠࠊ୰ኸ್ࠊ⟬⾡ᖹᆒࠊᗄఱᖹ ᆒࠊ⛣ືᖹᆒࠊ3 ḟࢫࣉࣛࣥࠊᣦᩘ㛵ᩘࠊໟ⤡⥺ࠊ ࢞࢘ࢩࣥࠊࣇ࣮࢚ࣜኚࠊ࣋ࢪ࢙ἲ࡞ࠊከᩘࡢ ᡭἲࡀ࠶ࡿ 227 - 229ࠋࡋࡋ࡞ࡀࡽࠊࡍ࡚ࡢᡭ㡰ࡀࠊ ‶㊊࡛ࡁࡿ⤖ᯝࢆ࠼ࡿ࠸࠺ࢃࡅ࡛ࡣ࡞࠸ࠋࡢ ᡭ㡰ࡀࠊ ᐃࡋࡓ᭤⥺ࡢᮏ㉁ⓗ࡞ᙧ≧ࢆᦆ࡞ࢃࡎࠊ ࣀࢬࢆపῶ࡛ࡁࡿࢆุ᩿ࡍࡿࡓࡵࠊ␗࡞ࡿࢫ࣒ ࣮ࢪࣥࢢ᧯సࢆヨࡉ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋࡍ࡞ࢃࡕࠊ 60°࢙࢘ࢵࢪࡢ⥺㔞ࣉࣟࣇ࡛ࣝࠊᲲ≧ࡢࣀࢬ ࢆ㝖ཤࡍࡿࡼ࠺࡞ሙྜ࡛࠶ࡿࠋ㐣ᗘࡢࢫ࣒࣮ࢪࣥࢢ ࡀᚲせ࡞ሙྜࡣࠊࢫ࢟ࣕࣥ㏿ᗘࡢపୗࡸࢧࣥࣉࣜࣥ ࢢ㛫㝸ࡢᘏ㛗࡞ࢆ⾜࠸ࠊࢹ࣮ࢱࢆᨵၿࡉࡏࡿࡇ ࡀᚲせ࡞ࡿࠋ 48 ࢭࣥࢱࣜࣥࢢ࣭ࢶ࣮ࣝࡣࠊ࣮࢜ࣉࣥ↷ᑕ㔝࡛ࡣ㐺 ษᶵ⬟ࡍࡿࠋࡋࡋ࡞ࡀࡽࠊࢭࣥࢱࣜࣥࢢࡢ㔞 ࡀ㐣࡛࠶ࡿ㸦࠼ࡤ 0.05 cm ࢆ㉸࠼ࡿ㸧ሙྜࡣࠊ ࢫ࢟ࣕࣥࢭࢵࢺࢵࣉࡢࣅ࣮࣒୰ᚰࡢᨵၿࢆ᳨ウ ࡍࡿᚲせࡀ࠶ࡿࠋ࠼ࡤࠊࢭࣥࢱࣜࣥࢢ࣭ࢶ࣮ࣝࡣ ࢙࢘ࢵࢪࢆ⏝࠸ࡓ↷ᑕ㔝ࡣᶵ⬟ࡋ࡞࠸ࡓࡵࠊ⨨ ㄗᕪࢆ⏕ࡌࡿྍ⬟ᛶࡀ࠶ࡿࠋ ࣉࣟࣇࣝࡢᑐ⛠ࢆ⾜࠺͆make symmetrical͇ ࡸ͆mirror͇ࢶ࣮ࣝࡣࠊ࣮࢜ࣉࣥ↷ᑕ㔝࡛ࡣ᭷⏝࡛ ࠶ࢁ࠺ࠋࡋࡋ࡞ࡀࡽࠊ㝖ཤࡍࡁ㠀ᑐ⛠ࡢ㔞ࡀ㐣 ࡞ሙྜ㸦࣮࢜ࣉࣥ↷ᑕ㔝ࡢࢫ࡛࢟ࣕࣥ 0.5%ࢆ㉸࠼ ࡿ㠀ᑐ⛠ᛶ࡞㸧ࠊ3 ḟඖỈࣇࣥࢺ࣒ࡀỈᖹタ⨨ࡉ ࢀ࡚࠸ࡿࠊࡲࡓࣅ࣮࣒ࡢᑐ⛠ᛶ࡞ࢆ☜ㄆࡍࡁ ࡛࠶ࡿࠋࡇࢀࡣ࢙࢘ࢵࢪ↷ᑕ㔝ࡽ࣮࢜ࣉࣥ↷ᑕ㔝 ࡢ㠀ᑐ⛠ࢆ㝖ཤࡍࡿ᪉ἲࡣ↓࠸ࡓࡵ࡛࠶ࡿࠋ ᐃࢹ ࣮ࢱ㔜࡞ຍᕤ㸦ࡍ࡞ࢃࡕࠊࢭࣥࢱࣜࣥࢢࠊࢫ࣒ ࣮ࢪࣥࢢࠊ㠀ᑐ⛠ࢆಟṇࡍࡿ࣑࣮ࣛࣜࣥࢢ㸧ࢆᚲせ ࡍࡿሙྜࡣࠊࢹ࣮ࢱࡢྲྀᚓࢆ᳨ウࡍࡁ࡛࠶ࡿࠋ Ⰻዲ࡞ ᐃࢹ࣮ࢱࢭࢵࢺࡣࠊ᭱ప㝈ࡢຍᕤ࡛༑ศ࡛ ࠶ࡿࠋ VI.B.1. ᩘᏛ㛵ᩘࣇࣝࢱ ࡓ࠸࡚࠸ࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣࠊࢫ࣒࣮ࢪࣥ ࢢࠊ࣑࣮ࣛࣜࣥࢢ࠾ࡼࡧࢧ࣐ࣛࢪࣥࢢ⏝ࡍࡿ 㛵ᩘࣇࣝࢱࡢヲ⣽࡞ㄝ᫂᭩ࡀ⏝ពࡉࢀ࡚࠸ࡿࠋ ࢩࢫࢸ࣒ࡢሗࡣࠊ〇㐀ᴗ⪅ࡢㄝ᫂᭩ࢆཧ↷ࡋ࡚ᚓ ࡿᚲせࡀ࠶ࡿࠋࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ᒓࡍࡿ㏻ VII. まとめと勧告 Jpn. J. Med. Phys. Vol. 33 No. 1 (2013) ᖖࡢࢯࣇࢺ࢙࢘ࡣࠊ⛣ືᖹᆒࠊ3 ḟࢫࣉࣛࣥࠊ ෆᤄᶵ⬟ࣇ࣮࢚ࣜኚ࡞ࡀ⏝࡛ࡁࡿࠋ࠶ࡽ (1) ⨨ࡢ✀㢮ࠊTPS ≉᭷࡞ᚲせ᮲௳ࠊ᧯సୖࡢ ࡌࡵᇶ‽࡞ࡿ↷ᑕ㔝ࢹ࣮ࢱẚ㍑ࡋ࡚ࠊࡇࢀࡽࡢ ၥ㢟Ⅼࠊ⨨ࡢ᧯స≧ែࣅ࣮࣒࢚ࢿࣝࢠ࣮ ᶵ⬟ࡢ᭷ຠᛶࢆ☜ㄆࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸ࠋ ࡼࡿࢹ࣮ࢱྲྀᚓࡢ⠊ᅖࢆつᐃࡍࡿࠋ (2) ᘧ(1)ࡢ௬ᐃᇶ࡙࠸࡚ࠊ⨨ࡢࢥ࣑ࢵࢩࣙࢽࣥ VI.B.2. ࢫ࣒࣮ࢪࣥࢢ࠾ࡅࡿࡺࡀࡳ ከࡃࡢࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣࠊ ᐃࢹ࣮ࢱࢆࢫ ࢢࡢࡓࡵᚲせ࡞㛫ࢆᴫ⟬ࡍࡿࠋ (3) ឤᗘࡀ㧗ࡃࠊయ✚ࡀᑠࡉࡃࠊࣀࢬࡀᑠࡉࡃࠊ ࣒࣮ࢪࣥࢢࡍࡿࡓࡵᵝࠎ࡞ࣇࣝࢱࡀ⏝ពࡉࢀ ࡘ⥺㔞⋡౫Ꮡᛶ࠾ࡼࡧ࢚ࢿࣝࢠ࣮౫Ꮡᛶࡢ ࡚࠸ࡿࠋࡶࡗࡶࡼࡃ⏝ࡉࢀࡿࡶࡢࡣࠊ3 ḟࢫࣉ ᑠࡉ࠸㐺ษ࡞᳨ฟჾࢆ⏝࠸ࡿࠋ ࣛࣥἲ࡛࠶ࡿࠋࡓࡔࡋ࢜ࣜࢪࢼࣝࢹ࣮ࢱࢆࢫ࣒࣮ ࢪࣥࢢࡍࡿࡇ࡛ࠊࢹ࣮ࢱࢆṍࡵ࡚ࡋࡲ࠺ࡇࡀ࠶ (4) య✚ࡢᑠࡉ࠸㟁㞳⟽⥺㔞ィࡣࠊගᏊ⥺ࡢ┦ᑐ⥺ 㔞 ᐃᮃࡲࡋ࠸ࠋ ࡿࠋ≉ࠊ༙ᙳ㒊ࡸ࢙࢘ࢵࢪࣉࣟࣇࣝࡢࡼ࠺࡞ (5) 㟁Ꮚ⥺⏝ࢲ࣮࢜ࢻ᳨ฟჾࡣࠊ㟁Ꮚ⥺ࡢ┦ᑐ⥺ ⥺㔞໙㓄ࡢࡁ࡞㡿ᇦ࡛㢧ⴭ࡞ࡿࠋFig. 13 ࠊࢫ 㔞ࡢ ᐃᮃࡲࡋ࠸ࠋࡓࡔࡋࠊไືᨺᑕ⥺ᑐ ࣒࣮ࢪࣥࢢࢆ⧞ࡾ㏉ࡋࡓࡇࡼࡿࣉࣟࣇࣝ ࡍࡿᛂ⟅ࡀ␗࡞ࡿࡀ࠶ࡿࡓࡵࠊไືᨺᑕ⥺ᡂ ࡢኚᙧࢆ♧ࡍࠋ ศࡣ㟁㞳⟽⥺㔞ィ࡛ ᐃࡍࡿࠋ ࢫ࣒࣮ࢪࣥࢢࡀఱᅇࡲ࡛チᐜࡉࢀࡿࡘ࠸࡚ (6) ᐃࢆ㛤ጞࡍࡿ๓ࠊࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡢ ࡢ࣮ࣝࣝࡸሗ࿌ࡣ࡞࠸ࠋ୍⯡ⓗࡣࢹ࣮ࢱࢆṍࡵࡎ ࣛ࣋ࣜࣥࢢ㸦x ࡸ y ࡞㍈ྡࡢタᐃ㸧タ⨨ ࠊ༢⣧ࢫ࣒࣮ࢪࣥࢢ࡛ࡁࡿࡼ࠺࡞࢜ࣜࢪࢼࣝࢹ ⨨ࢆ☜ㄆࡍࡿࠋ ࣮ࢱࢆྲྀᚓࡍࡿᚲせࡀ࠶ࡿࠋ1㹼2 ᅇࡢࢫ࣒࣮ࢪࣥࢢ (7) ࢫ࢟ࣕࢽࣥࢢࢩࢫࢸ࣒ࡣࠊ㐺ษ࡞㏿ᗘࠊ㐜ᘏ ࡣチᐜࡉࢀࡿࡔࢁ࠺ࠋᚋホ౯ࡢࡓࡵ࢜ࣜࢪࢼࣝ 㛫࠾ࡼࡧࢧࣥࣉࣜࣥࢢ㛫ࢆタᐃࡍࡿࠋ ࡢࢹ࣮ࢱࢆ↓ຍᕤࡢ≧ែ࡛ಖᏑࡍࡿࡇࢆᙉࡃ᥎ ዡࡍࡿࠋ (8) PDD ࡢࢫ࢟ࣕࣥࡣࠊ⾲㠃Ѝ῝㒊ࡼࡾ῝㒊Ѝ⾲㠃 ࡢ᪉ྥ࡛ྲྀᚓࡍࡿࠋ (9) ࢹ࣮ࢱࡢྲྀᚓせࡍࡿ㛫⢭ᗘࢆ⪃៖ࡋ࡚ࠊ VI.C. ࣀࣥࢫ࢟ࣕࣥࢹ࣮ࢱࡢຍᕤ 㐺ษ࡞ ᐃ㛫㝸ࢆタᐃࡍࡿࠋ ࣀࣥࢫ࢟ࣕࣥࢹ࣮ࢱࡘ࠸࡚ࡣࠊࣅ࣮࣒ࣃ࣓࣮ࣛ (10) ᳨ฟჾ㐺ษ࡞༳ຍ㟁ᅽᴟᛶࢆタᐃࡍࡿࠋ ࢱࡢ᫂☜࡞࢚࣮ࣛ㸦እࢀ್㸧ࢆᙉㄪ࡛ࡁࡿࡓࡵࠊࢢ (11) ↷ᑕ㔝ධࡿࢣ࣮ࣈࣝࡢ㛗ࡉࡣࠊྍ⬟࡞㝈ࡾ▷ ࣛࣇࢆ່ࡵࡿࠋ࠼ࡤࠊ↷ᑕ㔝ࢧࢬᑐࡍࡿ Scࠊ Sp ࡢࣉࣟࢵࢺࡣࠊᑠࡉ࠸↷ᑕ㔝࡛ᛴ⃭ኚࡋࠊ୍ ࡃࡍࡿࠋ (12) ࢹ࣮ࢱ ᐃࡢ✵㛫ศゎ⬟ࡀ᭱㧗࡞ࡿࡼ࠺ࠊ ᪉ࡁ࡞↷ᑕ㔝࡛ࡣࠊ⦆ࡸ࡞࣮࢝ࣈࢆ♧ࡉ࡞ࡅࢀ ᳨ฟჾࡢ▷㍈ࢆ ᐃ᪉ྥ୍⮴ࡉࡏࡿࠋ ࡤ࡞ࡽ࡞࠸ࠋ᫂ࡽ࣮࢝ࣈἢࢃ࡞࠸ ᐃⅬࡣࠊ (13) TPS ࡢᇶ‽᮲௳࡛ࡁࡿࡔࡅ㏆࠸ṇつࡢⅬ ィ⟬㛫㐪࠸ࢆ☜ㄆࡍࡁ࡛࠶ࡿࠋࡲࡓᚲせᛂࡌ ᡭ㡰ࢆ⏝࠸ࡿ㸦ࠊගᏊ⥺ࡣࠊ⾲㠃࡛ࡣΰධ ࡚ࠊࢹ࣮ࢱࡢ⢭ᗘࢆྥୖࡉࡏࡿࡓࡵ ᐃࡋ࡞ࡅࢀ 㟁Ꮚࡼࡿㄗᕪࢆᅇ㑊ࡍࡿࡓࡵࠊdmax ࡛ṇつ ࡤ࡞ࡽ࡞࠸ࠋ ࡋ࡞࠸࡞㸧ࠋ (14) ࡍ࡚ࡢ ᐃࢹ࣮ࢱࠊ⡆₩࡞࣏࣮ࣞࢺࢆ᭩ࡃࠋ VII. ࡲࡵ່࿌ (15) ࣏࣮ࣞࢺ ᐃࢹ࣮ࢱࢆ☜ㄆࡍࡿࠋ༑ศ࡞⤒ VII.A. ່࿌ 㦂ࢆ᭷ࡍࡿㄆᐃ་Ꮫ≀⌮ኈࡀ ᐃࢹ࣮ࢱࡢ⊂ ࡢ࣏࣮ࣞࢺྠᵝࠊࡇࡢᩥ❶ࡶᇳ➹ࡢ᭱᪂≧ ❧᳨ドࢆ⾜࠸ࠊ࣏࣮ࣞࢺࢆసᡂࡍࡿࠋ ἣࢆᫎࡋࡓࡶࡢ࡛࠶ࡿࠋᚋࡢ⒪⨨ࠊ⒪ィ ⏬ࠊ ᐃᢏ⾡ࡢⓎᒎࡼࡾࠊࡇࡢ࣏࣮ࣞࢺ࡛ࡢ᥎ዡ (16) ࡍ࡚ࡢ㟁Ꮚࢹ࣮ࢱࠊゎᯒࢹ࣮ࢱ࠾ࡼࡧࢫࣉࣞ ࢵࢻࢩ࣮ࢺࡢࣂࢵࢡࢵࣉࢆྲྀࡿࠋ ࡀ≧ἣྜࢃ࡞ࡃ࡞ࡿࡇࡶ⪃࠼ࡽࢀࡿࡓࡵࠊㄞ⪅ (17) ࣋ࣥࢲ࣮ࡽᥦ౪ࡉࢀࡓࢹ࣮ࢱࡣࠊཧ↷⏝ࡋ ࡣᖖ᭱᪂ࡢᢏ⾡ࢆᢕᥱࡋࠊࡇࡢ࣏࣮ࣞࢺࡣ୍⯡ⓗ ࡚ࡢࡳ⏝ࡍࡁ࡛࠶ࡿࠋࢥ࣑ࢵࢩࣙࢽࣥࢢࢹ ࡞ᡭ㡰᭩ࡋ࡚ά⏝ࡍࡁ࡛࠶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. ὀព (1) 〇㐀ᴗ⪅ࡀᥦ౪ࡋࡓࢹ࣮ࢱ౫Ꮡࡋ࡚ࡣ࠸ࡅ ࢙ࢵࢪ↷ᑕ㔝ࡢ㍈እ⥺㔞ࡢ⾲ (11) 㟁Ꮚ⥺ࢥ࣮ࣥࡢฟຊ⥺㔞ẚᐇຠ⥺※㊥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 ࣉࣟࣇࣝࡽ⟬ (2) ཷࡅධࢀヨ㦂ࡢࢹ࣮ࢱࡣࠊࢥ࣑ࢵࢩࣙࢽࣥࢢࢹ ฟࡋࡓࠊᇶ‽↷ᑕ㔝࡛ࡢ➼⥺㔞᭤⥺ࠋ ࣮ࢱࡢ௦⏝ࡣ࡞ࡽ࡞࠸ࠋཷࡅධࢀヨ㦂ࡢࢹ࣮ (14) ࡍ࡚ࡢࢫ࢟ࣕࣥࢹ࣮ࢱࡢ༳ๅ≀ ࢱࡣཧ↷ࡢࡳࢆ┠ⓗࡋ࡚࠾ࡾࠊ㝈ᐃⓗ࡞ᩓ (15) タෆࡸ␗࡞ࡿタ࡛ࡢ㢮ఝ⨨ࡢࢹ࣮ࢱ ᮲௳ୗ࡛ ᐃࡉࢀ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿࠋ ࡢẚ㍑ࠋࡴࡸࡳࢹ࣮ࢱࢆ⏝ࡋ࡚ࡣ࡞ࡽ࡞࠸ (3) ᳨ฟჾࡢ㍈᪉ྥ㸦ࢫ࢟ࣕࣥ᪉ྥ᳨ฟჾࡢ㛗㍈ ࡀࠊ࣋ࣥࢲ࣮ࡀᥦ౪ࡋࡓ͆golden͇ࢹ࣮ࢱẚ ࢆ୍⮴ࡉࡏࡿࡼ࠺࡞タ⨨㸧࡛ࢫ࢟ࣕࣥࡋ࡚ࡣ ࠸ࡅ࡞࠸ࠋ ㍑ࡍࡿࡇࡣၥ㢟࡞࠸ࠋ (16) ࣋ࣥࢲ࣮ࡀᥦ౪ࡋࡓࢹ࣮ࢱࡢẚ㍑⤖ᯝࠋࡓࡔ (4) ࢫ࣒࣮ࢪࣥࢢࡲࡓࡣᩘᏛⓗࣇࣝࢱࢆከ⏝ࡋ ࡋᥦ౪ࡉࢀࡓࢹ࣮ࢱࡣࠊཧ↷⏝ࡋ࡚ࡢࡳ⏝ ࡚ࠊࢹ࣮ࢱࢆ㐣ᗘຍᕤࡋ࡞࠸ࠋ ࡋࠊࢥ࣑ࢵࢩࣙࢽࣥࢢࢹ࣮ࢱࡢ௦⏝ࡣ࡞ࡽ࡞ (5) ᐃࢹ࣮ࢱࡣ༑ศὀពࢆᡶ࠺ࠋ௨㝆ࡢࢫ࢟ ࣕࣥࢆᐇࡍࡿ๓ࡲ࡛ࠊࡍ࡚ࡢලྜࡢၥ ࠸ࠋ (17) ࡍ࡚ࡢ㟁Ꮚࢹ࣮ࢱࠊゎᯒࡉࢀࡓࢹ࣮ࢱࢫࣉ 㢟Ⅼࢆㄪᰝࡋ࡚ᢕᥱࡍࡿᚲせࡀ࠶ࡿࠋ (6) ᑡ࡞ࡃࡶ୍᪥୍ᗘࡣࠊỈࣇࣥࢺ࣒ࡢỈᖹ ࣞࢵࢻࢩ࣮ࢺࡢࣂࢵࢡࢵࣉࢆྲྀࡿࠋ (18) ࣅ࣮࣒ࢹ࣮ࢱࡢྲྀᚓ᪉ἲࡑࡢ᮲௳ࡢヲ⣽ࢆࠊ ࢆ☜ㄆࡍࡿࠋ VII.C. ࢥ࣑ࢵࢩࣙࢽࣥࢢ࣏࣮ࣞࢺ ሗ࿌᭩ࡋ࡚ṧࡍࠋ ㅰ㎡ ࣏࣮ࣞࢺࡢ⦅㞟ᣦࢆᇳࡗ࡚㡬࠸ࡓ Sun ࢥ࣑ࢵࢩࣙࢽࣥࢢ⤖ᯝࡢ࣏࣮ࣞࢺࡣࠊᑗ᮶ⓗ᳨ ドࡍࡿࡇࡀ࡛ࡁࠊッゴࡢ㝿ㄝ᫂㈐௵ࢆᯝࡓࡏࡿ Nuclear ♫ࡢ James Pinkerton Ặࠊཌࡃឤㅰࢆ⏦ࡋ ࡼ࠺ࠊ᫂☜ࡘලయⓗグ㏙ࡋࠊࡉࡽ⨫ྡ᪥ ୖࡆࡲࡍࠋࡇࡢ࣏࣮ࣞࢺࢆᰯ㜀ࡋࡓ Ying Xiao Ặࠊ ࡶグ㍕ࡍࡿࡇࢆ᥎ዡࡍࡿࠋ David Followill Ặࠊ Per Halvorsen Ặࠊ Douglas Frye ௨ୗࡣࠊࢥ࣑ࢵࢩࣙࢽࣥࢢ࣏࣮ࣞࢺグ㍕ࡋ࡞ࡅࢀ Ặࠊ࠾ࡼࡧ⒪≀⌮ጤဨ㸦TPC㸧ࡢࡢከࡃࡢጤ ࡤ࡞ࡽ࡞࠸㡯┠ࡢ࡛࠶ࡿࠋ ဨឤㅰ⮴ࡋࡲࡍࠋ (1) ṇᘧ࡞ࢥ࣑ࢵࢩࣙࢽࣥࢢ࣏࣮ࣞࢺࡣࠊ௨ୗࡢ㡯 ┠ࢆ᫂☜ᴫㄝࡍࡿࠋ 㸦 ᐃィ⏬ࡢ⠊ᅖ㸦┠ⓗ㸧ࠊ ᐃ㡯┠ࠊ᪉ἲࠊ⏝ࡋࡓ⨨ࠊ⤖ᯝ࠾ࡼࡧ㐺 ษ࡞ὀពࡀࡉࢀࡓṇ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῝ࡉ౫Ꮡࡍࡿ࢙࢘ࢵࢪಀᩘࡢ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⪃ᩥ⊩ 1 TG-40, “Comprehensive QA for radiation oncology: Report of AAPM Radiation Therapy Committee Task Group 40,” Med. 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Metcalfe, “Comparison of effective source-surface distances for electron beams derived from measurements made under different scatter conditions,” Australas. 55 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ࡀࢇ࣭ឤᰁࢭࣥࢱ࣮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ኳᇽᏛᏛ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ᮾᏛᏛ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ᏛᏛ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: [email protected] 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: [email protected] 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 the Japan Society of Medical Physics to translate the following AAPM publication into Japanese and post on their website: Das, I., et al. “Accelerator beam data commissioning equipment and procedures: Report of 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 57
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