인체 영향과 방사선
• 인체는 여러가지 원자로 구성되어 있으며
방사선이 인체를 투과할때 인체를 구성하
는 원자에 에너지를 부여하고 에너지가 부
여된 원자는 전리와 여기등 물리적인 작용
• 전리와 여기작용은 세포핵에 있는 DNA로
구성된 염색체를 절단하거나 돌연변이등
의 이상을 일으키며 방사선장애의 근원
• X ray, 무선통신에 사용되는 microwave,
컴퓨터나 가전제품의 전자파(radiowave),
투열요법의 고열(diathermy)에서도 나옴.
• 파장이 길고 적은량의 에너지 조직내 이온
화하지 못하므로 해로운 영향이 없다.
• R(roentgen)- amount of ionization
produced by a beam of x-ray or gamma
rays in air.
• Exposure level- detection such as
• The amount of radiation energy
absorbed by irradiated tissue
• - radiation dose- specified in rads or
• 1 rad: 100ergs of energy absorbed per
gram of tissue
• 1 gray: 1 joule of energy per killogram
• = 100 rads.
• Depends -1, the number of ergs per gram
• 2, linear energy transfer of
radiation( density of ionization produced
• Alpha and neutron: 10-20 times more
ionization than X,gamma or beta
• == 각각다른 ㅡmultiplied by a radiation
• -new measurement-equivalent dose.
• Rem( roentgen-equivalent-man) or sieverts.
• X-ray,gamma, beta- factor -1
• = equivalent: roentgen,rads and rem
• Radiation dose-expressed in millirads instead
• Gray and sieverts –numerically equivalent:
1Sv= 100 rems =1Gy=100rad
• Nuclear medicine: quite low-mrem,mSv
Radiation dose to the patient
• Whole body- not receive a uniform
radiation throughout body
• Ex> Tc0-99mMAG3 5mci- red marrow:
9mrem, bladder-as high as 850mrem
• 장기별-sensitive or resistant
• Effective radiation dose
• Diagnostic nuclear : 100-100mrem(1-
10mSv)- 평균- 330mrem(3mSv)
• 비교: background radiation: 300mrem/yr
Back ground radiation
• Due to indoor raon etc
• Another source- human body itself
• Travel : 0.5mrem/hr
• US background radiation- about
선 량 한 도 :
직업상 피폭 일반인 피폭
유효선량한도 1 mSv/1년
(연간 50 mSv를 넘지 않는 한도)
피 부 150 mSv/1년 15 mSv/1년
500 mSv/1년 50 mSv/1년
증 상 비 고
0.25 Sv 거의 증상이 없음
0.5 Sv 임파구 일시적 감소
1 Sv 구토, 구역질, 전신권태, 임파구 현저한 감소
방사선피폭 결과 2일간 술취한 증상을 방사
1.5 Sv 방사선 숙취 50%
2 Sv 장기 백혈구 감소
사망률 50%를 반치사선량이라 부르고
4 Sv 사망 30일 이내에 50%
6 Sv 사망 14일 이내에 90%
7 Sv 사망 100% 100%는 치사선량임
Genetic effect of low dose
• Hiroshima/nagasaki descents
• - hazard 평가
• -no increase in incidence of prenatal
or neonatal death or malformation
• Complete data:not yet available
• : 종사자: 5rem/yr( 50mSv/yr)
• 10-15 rem(0.1-0.15Sv) to a fetus
• - increased incidence of fetal
malformation,death or persistent
damage of genetic material
• Fetal dose –nuclear medicine-
• Susceptible to congenital defect-1st T:
• frequent voiding등으로 최소화
Potentially pregnant women
• Ask when she had last mens period
• - postponed
• If patient dose not think she is pregnant,
• Fetal risk can be minimized by limiting
the radiation exposure to the first 10
days of mens cycle before ovulation
and potential conception.
• 확정적 영향(deterministic effects)
확정적 영향은 세포사에 따라 일어나며 피폭선량이 클
수록 많은 세포를 잃어버리게 되며 기관이나 조직의 기
능에 한층 중한 장해가 일어나는 영향이다. 임상적으로
병적상태라고 진단하는 데는 일정한 최소선량(문턱값)이
필요하다. 따라서 임상적으로 인정할 수 있는 장해의 발
생확률은 문턱값 이하의 선량에서는 영이 된다. 문턱값
을 넘으면 선량의 증가에 따라 장해의 중독도가 증가하
며, 또, 장해의 발생확률(빈도)도 급격히 증가해서 100%
의 환자에 장해가 발생하게 된다(그림-1). 또 방사선 치
료의 문턱값은 5년이내에 1-5%의 환자에게 장해를 일으
키는 선량으로 하고 있다.
• 확률적 영향(stochastic effects)
확률적 영향은 세포사보다 오히려 증식 가능한 하나의
손상 세포로부터 생겨나 선량이 증가하면 손상세포의 빈
도도 증가해서 결과로서 발암이나 자손에게 전해지는 유
전장해의 빈도를 높이는 것과 같은 영향이다. 손상 세포
가 임상적으로 발암 증상을 나타내기까지엔 다단계 과정
을 거쳐 10 억개 이상의 세포로 증식할 필요가 있다. 또
손상 생식세포도 자손의 유전장해로 되기엔 다단계의 수
정 선택과정을 거쳐 140조개의 세포로 증식할 필요가 있
다. 따라서 선량이 지나치게 크면 세포사 때문에 확률적
영향은 감소한다. 증식 가능한 손상세포는 선량이 낮더
라도 생겨날 수 있기 때문에 확률적 영향에는 문턱값 선
량이 없다고 가정할 수 있다. 또 선량의 증가에 따라 영
향의 정도는 변하지 않으며 영향의 발생확률만 증가한다.
• Ann ICRP. 2000;30(1):iii-viii, 1-43.
• Pregnancy and medical radiation.
• International Commission on Radiological Protection.
• Thousands of pregnant patients and radiation workers are exposed to ionising radiation each year. Lack of
knowledge is responsible for great anxiety and probably unnecessary termination of pregnancies. For many
patients, the exposure is appropriate, while for others the exposure may be inappropriate, placing the
unborn child at increased risk. Prenatal doses from most properly done diagnostic procedures present no
measurably increased risk of prenatal death, malformation, or impairment of mental development over the
background incidence of these entities. Higher doses, such as those involved in therapeutic procedures,
can result in significant fetal harm. The pregnant patient or worker has a right to know the magnitude and
type of potential radiation effects that might result from in utero exposure. Almost always, if a diagnostic
radiology examination is medically indicated, the risk to the mother of not doing the procedure is greater
than is the risk of potential harm to the fetus. Most nuclear medicine procedures do not cause large fetal
doses. However, some radiopharmaceuticals that are used in nuclear medicine can pose significant fetal
risks. It is important to ascertain whether a female patient is pregnant prior to radiotherapy. In pregnant
patients, cancers that are remote from the pelvis usually can be heated with radiotherapy. This however
requires careful planning. Cancers in the pelvis cannot be adequately treated during pregnancy without
severe or lethal consequences for the fetus. The basis for the control of the occupational exposure of
women who are not pregnant is the same as that for men. However, if a woman is, or may be, pregnant,
additional controls have to be considered to protect the unborn child. In many countries, radiation
exposure of pregnant females in biomedical research is not specifically prohibited. However, their
involvement in such research is very rare and should be discouraged. Termination of pregnancy is an
individual decision affected by many factors. Fetal doses below 100 mGy should not be considered a
reason for terminating a pregnancy. At fetal doses above this level, informed decisions should be made
based upon individual circumstances.
• Teratology. 1991 Feb;43(2):109-12.
• Exposure to ionizing radiation during pregnancy: perception of teratogenic risk
• Bentur Y, Horlatsch N, Koren G.
• Motherisk Program, Hospital for Sick Children, Toronto, Ontario, Canada.
• We quantified the perception of teratogenic risk in women attending the
Motherisk program for counseling about diagnostic radiation in pregnancy (n =
50) and compared it with a control group of women exposed to nonteratogenic
drugs and chemicals (n = 48). Before receiving known information about the
specific exposure, women exposed to radiation assigned themselves a
significantly higher teratogenic risk compared with the control group (25.5 +/-
4.3% versus 15.7 +/- 3.0% for major malformations, P less than 0.01). The
post-consultation perception of teratogenic risk did not differ
between the two groups. Special consideration and attention
should be given when counseling pregnant women exposed to
low-dose ionizing radiation, as their misperception of teratogenic
risk may lead them to unnecessary termination of their pregnancy.
Stochastic effect- as low as
• Hell J Nucl Med. 2007 Jan-Apr;10(1):48-55.
• [Fetus radiation doses from nuclear medicine and radiology diagnostic procedures. Potential risks and radiation protection
• [Article in Greek, Modern]
• Markou P.
• Health Care Unit Management, 9 Melenikou Str., 582 00 Edessa, Macedonia, Greece. email@example.com
• Although in pregnancy it is strongly recommended to avoid diagnostic nuclear medicine and radiology procedures, in cases of
clinical necessity or when pregnancy is not known to the physician, these diagnostic procedures are to be applied. In such
cases, counseling based on accurate information and comprehensive discussion about the risks of radiation exposure to the
fetus should follow. In this article, estimations of the absorbed radiation doses due to nuclear medicine and radiology diagnostic
procedures during the pregnancy and their possible risk effects to the fetus are examined and then discussed. Stochastic and
detrimental effects are evaluated with respect to other risk factors and related to the fetus absorbed radiation dose and to the
post-conception age. The possible termination of a pregnancy, due to radiation exposure is discussed. Special radiation
protection instructions are given for radiation exposures in cases of possible, confirmed or unknown pregnancies.
• It is concluded that nuclear medicine and radiology diagnostic
procedures, if not repeated during the pregnancy, are rarely an
indication for the termination of pregnancy, because the dose received
by the fetus is expected to be less than 100 mSv, which indicates the
threshold dose for having deterministic effects. Therefore, the risk for
the fetus due to these diagnostic procedures is low. However, stochastic
effects are still possible but will be minimized if the radiation absorbed
dose to the fetus is kept as low as possible.
Not teratogenic – diagnostic
• J Obstet Gynaecol Can. 2006 Jan;28(1):43-8.
• Diagnostic radiation in pregnancy: perception versus true risks.
• [Article in English, French]
• Cohen-Kerem R, Nulman I, Abramow-Newerly M, Medina D,
Maze R, Brent RL, Koren G.
• Motherisk Program, Division of Clinical Pharmacology and
Toxicology, Department of Pediatrics, the Hospital for Sick
Children, Toronto, Ontario.
• Significant numbers of therapeutic abortions are performed for
radiation-exposed pregnant women because of concerns about
the teratogenic risk. However, available data suggest that
current diagnostic radiation procedures are not teratogenic.
PET:7 +low dose CT:3
full dose CT:2-20mSv
• Radiat Prot Dosimetry. 2010 Feb 18. [Epub ahead of print]
• RADIATION EXPOSURE OF PATIENTS AND PERSONNEL FROM A PET/CT PROCEDURE WITH 18F-FDG.
• Leide-Svegborn S.
• Medical Radiation Physics, Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden.
• The positron emission tomography (PET)/computed tomography (CT) camera is a combination of a PET
camera and a CT. The image from the PET camera is based on the detection of radiation that is emitted
from a radioactive tracer, which has been given to the patient as an intravenous injection. The radiation
that is emitted from the radioactive tracer is more energetic than any other radiation used in medical
diagnostic procedures and this requires special radiation protection routines. The CT image is based on the
detection of radiation produced from an X-ray tube and transmitted through the patient. The radiation
exposure of the personnel during the CT procedure is generally very low. Regarding radiation exposure of
the patient, it is important to notice whether a CT scan has been performed prior to the PET/CT in order to
avoid any unnecessary irradiation. The total effective dose to the patient from a PET/CT procedure is
approximately 10 mSv. The major part comes from internal irradiation due to radiopharmaceuticals within
the patients (e.g. (18)F-FDG: approximately 6-7 mSv), and a minor part is due to the CT scan (low-dose
CT scan: approximately 2-4 mSv). If a full diagnostic CT investigation is performed, the effective dose may
be considerably higher. If the patient is pregnant, a PET/CT procedure should be avoided or postponed,
unless it is vital for the patient. An interruption in breastfeeding is not necessary after a PET/CT procedure
of the nursing mother. Close contact between the patient and a small child should however be avoided for
a couple of hours after the administration of the radiopharmaceutical. The radiation dose to the personnel
arises mainly due to handling of the radiopharmaceuticals (syringe withdrawal, injection, waste handling,
etc.) and from close contact to the patient. This radiation dose can be limited by using the inverse-square
law, i.e. by using the fact that the absorbed dose decreases substantially with increasing distance between
the radiation source and the personnel.
• No reason for termination of a
pregnancy at fetal whole body dose
Fetal effect from low-level