Journal List > Prog Med Phys > v.24(1) > 1098375

Cho, Huh, Kim, Choi, Kim, Cho, Cho, Min, Shin, Lee, Park, Kim, Choi, Kim, Ahn, Kim, and Han: Guideline for Imaging Dose on Image-Guided Radiation Therapy

Abstract

As image-guided radiation therapy (IGRT) has been commonly used for more accurate patient setup and monitoring tumor movement during radiation therapy, the necessity for management of imaging dose is increased. However, it has not been an interest issue to radiation therapy communities because the imaging dose is much lower than the therapeutic dose. However, since the cumulative dose from 4DCT and repeated imaging for daily setup verificationin would not be ignorable, appropriate dose management based on ALARA (As Low As Reasonably Achievable) principle is required. In this study, we aimed that (1) survey on imaging equipments and modalities used for IGRT, (2) estimation of IGRT imaging dose depending on treatment types and equipments, (3) collecting data of effective dose on treatment sites from each equipment and imaging protocol, and thus finally provide guideline for imaging dose reduction and optimization.

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Fig. 1.
CTDI 측정 팬텀, 10 cm 연필형 전리함 및 전리계21) 및 CTDI 의미 설명.
pmp-24-1f1.tif
Fig. 2.
두부 및 체부 CTDI 측정용 팬텀과 연필형 전리함 삽입 위치.
pmp-24-1f2.tif
Fig. 3.
CT검사 결과로 보고, 기록되는 CTDIvol 및 DLP 예.
pmp-24-1f3.tif
Fig. 4.
치료계획용 투시장치의 촬영조건에 대한 boxplot.
pmp-24-1f4.tif
Fig. 5.
치료계획용 CT의 촬영조건에 대한 boxplot. 관전압은 120 kVp로 모두 동일하였음.
pmp-24-1f5.tif
Fig. 6.
치료계획용 CT의 임상선량 현황 boxplot. CTDIvol (a) 및 DLP (b). 2009년 CT 엑스선검사에 환자선량 권고량 식약청 가이드라 인(K-DRL)과 비교하였음.
pmp-24-1f6.tif
Fig. 7.
치료계획용 CT촬영에 따른 유효선량. 일반 CT (a) 및 4DCT (b).
pmp-24-1f7.tif
Fig. 8.
영상유도 방사선치료의 장비별, 부위별 영상 선량.
pmp-24-1f8.tif
Fig. 9.
영상유도 방사선치료의 장비별, 부위별 유효선량.
pmp-24-1f9.tif
Fig. 10.
영상유도 방사선치료 시나리오 별 누적 유효선량.
pmp-24-1f10.tif
Table 1.
CT 엑스선검사에서의 환자선량 권고량과 외국 환자선량 권고량과의 비교(DLP).
  Korea-I, av (2008) Korea-E, av Korea-I, 3rd (2008) Korea-E, 3rd UK, 2003 Germany 2006 EU, 2000 IAEA 2006 ACR
Mean 3rd
Head 758.08 844.31 944.50 1,009.00 930 1,100 1,050 544 527
Abdomen 551.03 557.76 613.50 688.00 560 980 780 549 696

Korea-I, av: ImPACT scan으로 계산한 평균값, Korea-I, 3rd: ImPACT scan으로 계산한 제3사분위값, Korea-E, av: CT-EXPO로 계산한 평균값, Korea-E, 3rd: CT-EXPO로 계산한 제3사분위값.

Table 2.
국내 영상유도 방사선치료용 영상장비 보유 현황.
용도 구분(설치대수) 유형 구분 제조사별 장비 보유 현황
치료계획용 kV투시장치(41) Fluoroscopy Varian (25)/Nucletron (8)
  CBCT Siemens (4)/기타(4)
치료계획용 kV CT (68) Single scan (68) GE (28/24)/Philips (24/21)
  4DCT (53) Siemens (11/8)/기타(3/0)
치료확인용 kV 투시장치(73) Flat-panel 검출기 Cyberknife (9)/BrainLab Exactrac (8)
  Fluoroscopy Varian OBI (48)/Elekta XVI (6)/Siemens (2)
치료확인용 MV 투시장치(115) Flat-panel 검출기(EPID) Varian (90)/Siemens (15)/Elekta (10)
치료확인용 CT (17) kV CT Siemens CT-on-rails (1)
  MV CT Tomotherapy (16)
치료확인용 CBCT (57) kV cone-beam CT Varian OBI (48)/Elekta XVI (6)
  MV cone-beam CT Siemens MV CBCT (3)
Table 3.
치료 부위별, 장비별 영상유도 방사선 치료시행 현황.
영상유도방사선치료의 빈도(회) 두경부(H&N) 흉부(Lung) 복부/골반부(liver, prostate)
일반 IMRT/SBRT 일반 IMRT/SBRT T 일반 IMRT/SBRT
Simulator   필요시 필요시   필요시
CT (회/환자) Planning CT 1.3 1.3 1.2 1.3 1.2 1.1
  4DCT 1.3 1.2 1.3 1.2
2D EPID (회/주) Varian/Siemens 0.8 2.6 0.7 3.1 0.7 2.8
  /Elekta            
2D KV (회/주) Varian/Elekta 1.5 3.9 1.9 3.4 1.4 3.9
  Cyberknife 5 5 5
  ExacTrac 5
3D CBCT (회/주) Varian/Elekta 2.0 4.0 2.0 4.3 3.0 4.0
  Siemens (MV) 1 1 1 1 1 1
MVCT (회/주) Tomotherapy 0 5 0 5 0 5
Table 4.
치료계획용 투시장치의 부위별 임상 촬영조건 현황.
  Sites Avg. SD 25th percentiles 75th percentiles Min Max
kV HN 75.8 15.7 68.8 80.0 50.0 105.0
  Chest 78.5 17.2 71.5 92.5 50.0 95.0
  Pelvis 90.1 20.3 82.8 106.3 50.0 110.0
mAs HN 35.5 37.2 5.4 80.0 3.2 80.0
  Chest 28.5 34.1 4.0 51.3 3.2 80.0
  Pelivs 26.3 30.8 3.6 45.8 3.2 80.0
Table 5.
치료계획용 CT 임상 관전류 촬영조건 분포 현황.
Sites Avg. SD 25th percentiles 75th percentiles Min Max
HN 157.4 140.1 30.0 220.0 10.0 440.0
Chest 121.1 125.9 30.0 200.0 10.0 469.0
Pelvis 121.4 114.7 40.0 205.0 10.0 407.0
Table 6.
치료계획용 kV 투시장치의 임상 촬영 조건별 일반촬영 선량.
    Radiograph mode ESDa) Eff doseb)
    kVp mA ms mAs mGy mSv
Head AP 80 100 400 40 2.90 0.015
& neck LAT           0.019
Chest AP 80 100 400 40 2.90 0.589
  LAT           0.121
Pelvis AP 90 200 400 80 7.33 0.398
  LAT           0.0354

a) ESD: Entrance Skin Dose, (Focus-Skin Distance=85 cm).

b) calculated using OrgDose software

Table 7.
진단 방사선 검사에서의 성인 환자의 권고 선량(IAEA BSS No.115).
부위 조사방향 ESD/radiograph (mGy)
Head & neck PA 5
  LAT 3
Chest PA 0.4
  LAT 1.5
Abdomen/Pelvis AP 10
투시촬영 Normal 25 mGy/min
  High level 100 mGy/min (IVR)
Table 8.
치료계획용 kV 투시장치의 임상 촬영 조건별 투시촬영 선량율.
  Fluoroscopy mode (continuous) ESD/min Eff dose ratea) (mSv/min)
  kVp mA mA-min mGy/min (AP/LAT)
Head & neck 70 3 180 8.0 0.337 (0.148/0.189)
Chest 70 5 300 13.5 5.12 (3.87/1.25)
Pelvis 90 15 900 69.0 5.10 (4.68/0.417)

a )X-ray tube Output (free-in-air) 2.7 mGy/mA-min (70 kVp, 3 mA, 8.1 mGy/min, SCD=85 cm).

Table 9.
치료확인용 kV 투시장치(Varian OBI)의 임상 촬영 조건별 일반촬영 선량.
Site kV mA ms mAs ESD per image (mGy) Eff dose (mSv)
Head AP 100 200 40 8 1.16 0.0166
  & neck LAT 70 200 25 5 0.37 0.0043
Chest AP 75 200 25 5 0.50 0.226
  LAT 95 200 200 40 6.56 0.613
Pelvis AP 75 200 50 10 0.96 0.231
  LAT 105 200 400 80 17.32 0.48
Table 10.
치료확인용 kV 투시장치(Elekta XVI)의 임상 촬영 조건별 일반촬영 선량.
Site kV mA ms mAs ESD per image (mGy) Eff dose
Head AP 100 10 10 0.1 0.09 0.00134
  & neck LAT 100 10 10 0.1 0.08 0.00138
Chest AP 120 25 40 1 0.89 0.331
  LAT 120 25 40 1 0.85 0.0348
Pelvis AP 120 25 40 1 0.90 0.34
  LAT 120 32 40 1.28 1.04 0.0378
Table 11.
치료확인용 kV 투시장치(Cyberknife)의 임상 촬영 조건별 일반촬영 선량.
Site kV mA ms mAs ESD per image (mGy) ED (mSv) per image pair
Head 110 100 100 10 0.50 0.009
Chest 110 150 100 15 0.53 0.054
Prostate 120 150 100 15 0.64 0.07
Table 12.
Cyberknife 조건별 선량 참고문헌30) 비교치.
Anatomy kVp mAs ESD/image (mGy) A (cm2) F (mSv/mGy -cm2×10−5) ED (mSv) per image pair
Head 115 10 0.22 225 4.5 0.0045
Chest 120 11.5 0.28 225 20.5 0.0258
Pelvis 124 34.5 0.91 225 19.9 0.0815
Table 13.
치료확인용 kV 투시장치(Exactrac)의 임상 촬영 조건별 일반촬영 선량.
Site kV mA ms mAs s ESD per image (mGy) ED (mSv) per image pair
Head & neck 100 80 80 6.4 0.39 0.011
Chest 120 160 160 25.6 0.90 0.214
Abdomen 120 160 130 20.8 0.77 0.058
Table 14.
치료확인용 kV 투시장치 (Varian OBI, Elekta XVI)의 투시촬영 선량율.
    kV mA ms mAs Frame mGy/mAs-frame- mGy/min
Varian AP 74 50 50 2.5 90 0.02 4.5
  OBI                
Elekta AP 120 25 40 1 150 0.12 18
  XVI                
Table 15.
치료계획용 kV CT (GE Lightspeed)의 임상 촬영 조건별 CTDI 측정치.
    kVp mA Rot time (sec) CTDIw CTDIvol %difference
Head 2.5×4i 120 200 1 30 36.58 122%
Body 2.5×8i 120 200 1 13.2 14.8 112%
Table 16.
ED/DLP conversion factor.32)
  Head & neck Chest Pelvis
mSv/mGy-cm 0.0054 0.017 0.019
Table 17.
치료확인용 kV CBCT의 임상 촬영 조건별 CTDI 측정치.35)
Site Elekta synergya) Varian OBIa)
Head standard Chest Pelvis Head standard Chest Pelvis
kV Collimation S20 M20 M10      
kV filter F0 F1 F1 Full bowtie Half bowtie Half bowtie
kVp 100 120 120 100 110 125
mA 10 40 64 20 20 80
ms/projection 10 40 40 20 20 13
No of projections 361 643 643 360 655 655
Total mAs 36.1 1,028.8 1,646.1 145 262 680
Measured HVL (mm Al) 5.9 8.9 8.9 5.4 5.7 6.4
Acquisition angle 350∼190 cw 273∼269 cw 273∼269 cw 88∼292 cw/ccw 88∼92 cw/ccw 88∼92 cw/ccw
Acquisition time (s) 70 120 120 30 60 60
Axial field of view (cm) 27 41 41 25 45 45
Long field of view (cm) 26 26 12.5 18 16 16
CBDIw36) (mGy) 0.98 16.62 24.13 4.6 5.8 20.28
CBDIw (mGy)b) 0.94 21.45 22.87 4.8 5.91 20.12
Effective dose (mSv)b) 0.13 9.48 5.43 0.47 1.61 6.11
by ED/DLP conv29)            
Effective dose (mSv)20) 0.04 7.15 3.73 0.12 1.82 4.34

a) Software version 4.0 for XVI and software version 1.4 for OBI,

b) this study (XVI촬영조건이 다름, Chest/Pelvis F0 (bowtie removed) 모드에서 25 mA/40 ms로 측정).

Table 18.
치료확인용 MV 투시의 임상 촬영 조건별 선량 평가치.
  Head & neck Chest Pelvis
Avg dose (mGy) 28 25 30
Eff dose (mSv)a) 2.8 5.1 5.9
Conv factor (mSv/MU)37) 0.12 2.15 0.33
Eff dose (mSv) per 2MUb) 0.5 8.6 1.35

a) 치료빔 선량계산 프로그램인 Eclipse를 사용하여 장기별로 계 산된 선량에 ICRP-60 조직가중치를 적용하여 산출한 값임.

b) 참 고문헌

37) 에서 제시하고 있는 Monitor Unit 당 유효선량 변환인 자를 적용하여 산출한 값임. 본 연구의 유효선량 평가치와 5배 이상의 큰 차이를 보이고 있어 적용에 주의가 요구됨.

Table 19.
치료확인용 kV CBCT 부위별 선량 평가치.
Scan Mode Head scan Chest scan Pelvis scan
Organ Oral mucosa Parotid Lung Heart Bladder Rectum
Varian Dose (mGy) 3.27 7.23 10.38 9.61 27.01 24.91
CBCT ImPACTa) 3.36 2.94 5.8 4.87 20.28 20.28
  %difference 3% –59% –44% –49% –25% –19%
Dose (mGy) Elekta 0.43 1.05 25.8 24.82 16.52 15.56
ImPACTa) CBCT 0.77 0.8 19.3 14.65 19.56 19.56
  %difference 79% –24% –25% –41% 18% 26%

a) ImPACT 선량은 CTDI 팬텀기준으로 계산된 결과이며, 본 측정 에서 사용한 인체모형팬텀과 다름.

Table 20.
치료확인용 MVCT 부위별 선량 평가치.
Site Head & neck Chest Pelvis
Measured organs Oral mucosa Parotid Lung Heart Bladder Rectum
4.8 4.95 4.57 4.6 4.2 4.1
Average dose 4.88 4.59 4.15
  (mGy)a)            
DLP (25 cmscan-length) 121.88 114.63 103.75
ED/DLP conv. 0.0054 0.017 0.019
  factor32)            
  (mSv/mGy∗cm)            
Effective dose 0.66 1.95 1.97
  (mSv)            

a )참고문헌39)에서는 CTDI 측정용 팬텀을 이용하여 Coarse, Normal, Fine 모드별로 9.5, 14.7, 29.9 mGy로 평가함.

Table 21.
치료확인용 MV CBCT 부위별 선량 평가치.
Measured organs Head & neck Chest Pelvis
Oral mucosa Parotid Lung Heart Bladder Rectum
131.1 127.3 125 118.3 109.9 112.2
Average dose (mGy) 129.20 121.65 111.05
DLP (25 cm scan-length) 3,230.00 3,041.25 2,776.25
ED/DLP conv. factor32) (mSv/mGy∗cm) 0.0054 0.017 0.019
Effective dose (mSv) 17.44 51.70 52.75
Conv factor (mSv/MU)37) 0.12 2.15 0.33
Eff dose (mSv) per 15 MU 1.8 32.25 4.95
Measured dose (mGy)40) 47.9 67.4
Table 22.
영상유도 방사선치료에 있어 영상기법별, 부위별 기준선량 권고안.
  촬영조건 기준(mGy) 비고
일반촬영(ESD/radiograph: mGy) Head & neck PA 5  
    LAT 3  
  Chest PA 0.4  
    LAT 1.5 IAEA
  Abdomen/Pelvis AP 10 BSS-115
투시촬영(ESD/min: mGy/min) Normal   25 mGy/min  
  High level   100 mGy/min (IVR)  
치료계획용CT (CTDIvol: mGy) Head   60 식약청 방사선안전시리즈19
  Abdomen   20  
4DCT (CTDIvol: mGy) Abdomen   60 본 연구
kVCBCT Head   5 제조사 스캔모드 및 본연구
  Chest   15  
  Pelvis   25  
EPID (ESD: mGy)     50 10 mGy/MU
MVCT (CTDI: mGy)     30 제조사 스캔모드
MVCBCT (CTDI: mGy)     90 10 mGy/MU
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