Guideline for Imaging Dose on Image-Guided Radiation Therapy

Byung Chul Cho; Hyun Do Huh; Jin Sung Kim; Jin Ho Choi; Seong Hoon Kim; Kwang Hwan Cho; Sam Ju Cho; Chul Kee Min; Dong Oh Shin; Sang Hoon Lee; Dong Wook Park; Kum Bae Kim; Sang Hyoun Choi; Hye Young Kim; Woo-sang Ahn; Tae Hyeong Kim; Su Cheol Han

doi:10.14316/pmp.2013.24.1.1

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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

Review Article

Progress in Medical Physics 2013;24(1):1-24.

Published online: 20 March 2013

DOI: https://doi.org/10.14316/pmp.2013.24.1.1

Guideline for Imaging Dose on Image-Guided Radiation Therapy

Byung Chul Cho^∗,, Hyun Do Huh^†, Jin Sung Kim^‡, Jin Ho Choi^§, Seong Hoon Kim^∥, Kwang Hwan Cho^¶, Sam Ju Cho^∗∗, Chul Kee Min^¶, Dong Oh Shin^††, Sang Hoon Lee^‡‡, Dong Wook Park^§§, Kum Bae Kim^∥∥, Sang Hyoun Choi^†, Hye Young Kim^†, Woo-sang Ahn^∗, Tae Hyeong Kim^∥∥, Su Cheol Han^∥∥

^∗Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea

^†Inha Univeristy Hospital, Incheon, Korea

^‡Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea

^§College of Medicine, Gachon University Gil Hospital, Incheon, Korea

^∥Hanyang University Hospital, Seoul, Korea

^¶ Soonchunhyang University Hospital, College of Medicine, Asan, Korea

^∗∗Department of Radiological Science, College of Health Science, Eulji University, Seongnam, Department of Radiation Oncology, Korea

^††College of Medicine, Kyung Hee University Medical Center, Suwon, Korea

^‡‡Cheil General Hospital & Women's Healthcare Center, Kwandong University College of Medicine, Seoul, Korea

^§§Inje University Hospital, Seoul, Korea

^∥∥Research Center for Radiotherapy, Korea Institute of Radiological & Medical Sciences, Seoul, Korea

책임저자：조병철, (138-736) 서울시 송파구 올림픽로43길 88울산대학교 의과대학 서울아산병원 방사선종양학과 Tel: 02)3010-4433, Fax: 02)3010-6950 E-mail: bccho@amc.seoul.kr

Received 26 December 2012 Accepted 4 March 2013

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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.

Keywords: Radiation therapy, Image-guided radiation therapy, Imaging dose, Effective dose

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Fig. 1.

CTDI 측정 팬텀, 10 cm 연필형 전리함 및 전리계²¹⁾ 및 CTDI 의미 설명.

Fig. 2.

두부 및 체부 CTDI 측정용 팬텀과 연필형 전리함 삽입 위치.

Fig. 3.

CT검사 결과로 보고, 기록되는 CTDIvol 및 DLP 예.

Fig. 4.

치료계획용 투시장치의 촬영조건에 대한 boxplot.

Fig. 5.

치료계획용 CT의 촬영조건에 대한 boxplot. 관전압은 120 kVp로 모두 동일하였음.

Fig. 6.

치료계획용 CT의 임상선량 현황 boxplot. CTDI_vol (a) 및 DLP (b). 2009년 CT 엑스선검사에 환자선량 권고량 식약청 가이드라 인(K-DRL)과 비교하였음.

Fig. 7.

치료계획용 CT촬영에 따른 유효선량. 일반 CT (a) 및 4DCT (b).

Fig. 8.

영상유도 방사선치료의 장비별, 부위별 영상 선량.

Fig. 9.

영상유도 방사선치료의 장비별, 부위별 유효선량.

Fig. 10.

영상유도 방사선치료 시나리오 별 누적 유효선량.

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
	Korea-I, av (2008)	Korea-E, av	Korea-I, 3rd (2008)	Korea-E, 3rd	UK, 2003	Germany 2006	EU, 2000	Mean	3rd	ACR
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)
영상유도방사선치료의 빈도(회)		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	25^th percentiles	75^th 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	25^th percentiles	75^th 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				ESD^a)	Eff dose^b)
		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 rate^a) (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 synergy^a)			Varian OBI^a)
Site	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 2MU^b)	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 ImPACT^a)	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
ImPACT^a) 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
Measured organs	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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