SOURCES, EFFECTS
AND RISKSOF IONIZING RADIATION
United Nations Scientific Committee on the Effectsof Atomic Radiation
1988 Report to the General Assembly, with annexes

UNITED NATIONSNew York, 1988

NOTE
The report of the Committee without its annexes appears as Official Records of theGeneral Assembly, Forty-third Session, Supplement No. 45 (A/43/45).
The designations employed and the presentation of material in this publication d o
not imply the expression of any opinion whatsoever on the part of the Secretariat of theUnited Nations concerning the legal status of any country, territory, city or area. or of its
authorities, or concerning the delimitation of its frontiers o r boundaries.

UNITED NATIONS PUBLICATION
Sales No. E.88.IX.7
ISBN 92-1- 142143-8
09000PANNEX C
Exposures from medical uses of radiation

CONTENTS
Poroprophs

1. DIAGNOSTIC hlEDlCAL X-RAY
EXAhflNATlONS ...............

14-138Frequency and trends ..........

14-41

A.

B.

Age and sex distribution of patientsC'.

Impact of specialized types of
examinations .................

48-56

D.

Exposure and absorbed dose.. ...

57-90

E.

Causes of dose variation and possibilities for dose reduction. .....

91-102

F.

42-47

1

Paragraphs

11. DIAGNOSTIC USE O F RADIOPHARMACEUTICALS.. ......... 139-154
A. Frequency and trends .......... 139- 144
B. Age and sex distribution of patients
145
C.
D.

E.

hleasures of risk .............. 103-122

G. World-wide estimates of doses fromdiagnostic x-ray examinations ...

123-126

H. Occupational exposure from diagnostic radiography. ...........

127- 131

I.

I

Future trends in diagnostic radiography ...................... 132-138

Introduction
1. T h e Committee has previously reviewed d a t a o n
exposures from medical uses of radiation in its
Reports of 1958 [Ul], 1962 [U2], 1972 [U3], 1977 [U4]a n d 1982 [U5]. Medical radiation may be incurredf r o m (a) diagnostic a n d interventional x-ray examinations; (b) diagnostic nuclear medicine examinations;a n d (c) radiation therapy f r o m either external o rinternal sources. In many countries. diagnostic medical
examinations contribute t h e largest proportion of the

Impact of new technologies .....
Ahsorbed dose ................
Occupational exposure from diagnostic nuclear medicine. .......

146

111. THERAPEUTIC USES O F RADIA-TION ...........................
A. Frequency and trends ..........
B. Absorbed dose ................
C. Occupational exposure from radiation therapy ..................

IV. SUMhlARY .....................
Tables ...............................
References ............................

269
30 1

collective effective dose equivalent from m a n - m a d esources received by the population.

2. T h e a i m of this Annex is t o assess the magnitude o fradiation exposures delivered world-wide in t h e courseof medical practice. Once this has been achieved,(a) sources of radiation exposure may b e c o m p a r e d ;(b) areas of concern can be identified; (c) possible
detriment estimated: a n d (d) efforts channelled f o r an
o p t i m u m global radiation dose reduction (if indicated).
T h u s f a r . the Committee has estimated that t h ecollective effective dose equivalent for the world fromdiagnostic medical radiation is about 400 man Sv per
million population (i.e., about 0.4 per caput).

female breast). For calculation of possible subsequentcancer induction. age at exposure was recognized to
be important, but little data existed on this parameter.

3. For diagnostic and interventional uses of radiation,
there is a possibility of dose reduction, although one
must be careful not to decrease at the same time theassociated benefits. Medical radiation differs from otherradiation sources in several ways. The first is that. withthe exception of medical occupational radiation exposure, those receiving the doses delivered in the courseof medical procedures are those who are expected tobenefit directly from such procedures. The second
difference is that the dose to patients during radiography is usually received over a short time and mostoften involves only a limited portion of the body. A third
difference from other sources is that the exposed
population is highly selected, insofar as many of the
exposed individuals are suffering from some form of
illness and insofar as their age distribution is quite
different from the age distribution of the population atlarge.

7. Although it is of interest for the Committee's
purposes to compare the risk from medical radiation
with risks from other sources of man-made radiation
or from n a t ~ ~ r backgroundalradiation, such comparison has always posed a difficult problem. The effectsof radiation depend upon the energy of the radiation,
instantaneous dose rate. the time over which the total
dose is received, and the part of the body exposed. In
this respect, diagnostic examinations are markedly
different from radiotherapy procedures, in which
substantially higher doses are given to a much smallergroup of patients, in whom non-stochastic effects arepresent in the short tern]. The Committee has alivays
felt that the potential stochastic risks to patients fromdiagnostic medical radiation and nuclear medicine
should not be summed or compounded with the risks
from radiotherapy. The reasons for this arc that therisk coefficient for a given effect may vary with themagnitude of the absorbed dose and the dose rate. In
addition, the radiation risk coefficient for cancer
patients is unknown and their lifespan and age
distribution are likely to be different from otherpopulations. Radiation therapy is therefore assessed inthis Annex only in terms of average absorbed doses inorgans. It would be of interest to evaluate the absorbed
doses to tissues outside the target volume in patients
who have undergone radiation therapy for estimationof possible later stochastic effects. L'nfortunately, theCommittee has been unable to obtain data on thenumber and exact treatment regimes that have beenutilized.

One of the limitations of the previous Reports of theCommittee, as well as of this Annex. is that good data on
frequency of examinations and absorbed dose frommedical examinations and occupational sources areavailable predominantly from developed countries,
which account for less than 25% of the world's
population. Fragmentary data on examination rates
and numbers of machines and little or no data on
absorbed doses are available for another 25% of the
population, and no data are available at all for 50% of
the world's population.
4.

5. The present availability of radiodiagnosis is very
uneven throughout the world: one x-ray machine isshared by fewer than 2.000 people in some countries
and by 100.000-600,000 people in other countries.
The frequency of procedures is also very uneven(15-20 procedures annually per 1.000 population insome countries and about 1.000 procedures annuallyper 1.000 population in others) [RI]. At present, there
are approximately 5 lo9 people in the world and someauthors indicate that more than three quarters of theworld's population have no chance of receiving any
radiological examination, regardless of what disease
they may have. In many developing countries, betlveen
30% and 70% of x-ray machines are out of order[M32, P2]. The lack of good data from areas that
account for approximately three quarters of theworld's population has led the Committee to adopt an
extrapolation procedure for estimating world-\vide
medical use of radiation.
In the UNSCEAR 1958 Report [Ul], the Committee was predominantly interested in exposures thatmight have hereditary effects, so it calculated agenetically significant dose (GSD). It became evident
during the 1958 analysis that a major portion of dose
was contributed by relatively few types of examinations. By 1977, and even more by 1982, the Committee
became interested in estimating the mean doses toother tissues, particularly those tissues regarded as
more susceptible to the induction of stochastic effects(e.g., the thyroid, active bone marrow, the lung and the
6.

8. In 1977, the International Commission on Radiological Protection (ICRP) introduced a quantity called
the "effective dose equivalent", defined as the sum of
all the organ dose equivalents weighted for the relatitle
radiation risk. 'The effective dose rouivalent as definedfor purposes of radiation protection [I?] should nor.
in principle, be used to estimate the detriment in
population groups with sex or age distributions thatdiffer significantly from those of the working population, and i t was not the original intention of the ICRP
that the effective dose equivalent concept should be
extended to patients. However, in the absence of good
age distribution data on exposed patients, the Committee utilized the effec1ii.e dose equivalent concept in
the UNSCEAR 1982 Keport [U5] as the best available
estimate of medical esposure for the purpose ofconi~arisonwith other sources of radiation rxDosure.
This .4nnex examines the age distribution of populations undergoing different radiological examinations
and points more specifically to the limitations to theuse or collective effective dose equivalent for estin~ating detriment. A more detailed discussion of thisproblem is presented in section I.F.
9. In addition to examining the population structure
itself, the Committee felt that it was important toexamine trends in the utilization of various procedures
used for a gi\en diagnostic objective as well as trends
in types of equipment. Over the past decade there
have been many technological adiances that may beaffecting medical exposure: old techniques are being
replaced by new ones; additional examinations arebeing performed; and procedures are being carried out
with different types of equipment, leading to increases
or decreases in the mean absorbed doses in organs in
the course of examinations. This Annex examines trends
where sequential data are available. Although it is clearthat trends vary markedly from country to country, it
appears that, globally, the extent to which medical
radiation is utilized is increasing. The World HealthOrganization published a report [W19] containing
recommendations intended to alert the medical andgovernmental communities t o the fact that, particularly
in industrialized countries. many clinically unproductive radiological examinations are being performed. In
contrast. there is probably substantial under-utilization in developing countries.

medical practices are computed to evaluate the contribution that medical practice makes to man's total
radiation exposure. Since these data may also be used
to determine whether special population groups arebeing highly exposed, they may be of epidemiologicalinterest. There remain some difficulties. however, incomparison of absorbed doses. because the techniquespresented in the radiologic physics literature sometimes measure exposure rather than absorbed doses.
The determination of interest is the average absorbed
dose in an organ. There is considerable \variability
from study t o study in modelling, computational
techniques and assumptions utilized. Because organ
doses vary markedly from one procedure to another.
it is useful to examine this variation within a given
country as well as from country to country, in searchof the underlying causes.

10. In a n attempt to estimate the global use of
medical radiation, the Committee has made use of thegood correlations that exist between population per xray machine and population per physician (Figure I).
A good correlation has been found between thenumber of x-ray examinations per unit of populationa n d the number of physicians per population [M27].
Four levels of health care have been defined, based
upon the number of population per physician in agiven country in 1982. In countries with the highest
level of health care (level I), more than one physician
is available per 1,000 population. In countries of thenext category (level 11). one physician is available per
1.000-3,000 population. In countries with lower levels of
health care, one physician serves 3,000-10,000 people(level 111) and more than 10,000 people (level IV). By
estimating the average number of medical radiation
examinations in countries of the various health carelevels and reported doses from representative countries, the doses to the world population can be
determined. This approach is used in evaluating thedoses from x-ray examinations, from diagnostic use ofradiopharmaceuticals, as well as therapeutic uses ofradiation.

12. While absorbed dose data exist for many radiographic and nuclear medicine procedures, this Annex
suggests that previous estimates of absorbed dose to
the world's population may be somewhat low. The
two most important reasons for this suspicion are thewidespread use of fluoroscopy in developing countries
and the large number of malfunctioning machines
producing high absorbed doses (neither factor was
widely appreciated in the past) [B16, Dl]. For
example, in the People's Republic of China, mostradiographic examinations are performed with fluoroscopy machines that d o not have image intensification
systems [S32, 241, resulting in higher dose equivalents
per examination than in some other countries.

I I . This Annex also reviews doses to particularorgans from various types of medical examinations.
The individual and collective organ doses from various

13. Finally, this Annex examines expected changes in
the magnitude of medical exposure through the year
3000. The Committee recognizes that there is expected
to be (a) a significant increase in total population of
the world; (b) a marked aging of the population in
many, mostly developed countries, with increased
proportions of the population over the ages of 60 a n d80; (c) an increase in the proportion of the world's
population residing in cities; and, finally, (d) a shift inthe spectrum of diseases [04]. All of these factors are
expected to play a significant role in the future use,
availability and need for medical radiation.

I.

DIAGNOSTIC MEDICAL X-RAY
EXAlClINATIONSA.

FREQUENCY AND TRENDS

14. In the UNSCEAR 1977 Report [U4], data o n thefrequency of diagnostic x-ray examinations wereavailable for only three countries: Japan, Sweden andthe United States of America. The UNSCEAR 1982
Report [U5] reviewed the annual frequency of these
examinations in several countries; however, it wasdifficult to discern world-wide trends since mostcountries had not conducted sequential surveys.
100

1000
lo000
POPULATION PER PHYSIC IAN

Figure I. Correlation between population per physician andpopulation per x-ray machine in various countries.
[M27,U6, U7. U8]

15. Information is now available from some othercountries. The annual frequency of procedures perperson varies significantly between countries [C7]. In
many developing countries. radiology is used about

30 times less often per caput than in industrializedcountries. The consumption of radiographic film perunit population is a poor parameter for assessing the
global medical radiation exposure of the population
because in many countries there is a preponderance ofmass miniature radiography or fluoroscopy and theserequire higher values of dose. In its attempt to assess
data, the Committee has therefore concentrated on
numbers and types of machines as well as o n thenumber of procedures.
16. Informatior. on the annual frequency of diagnostic x-ray examinations in 13 countries of level I
health care and one country of level I1 health care iscollected in Table 1. The total frequencies in thesecountries range from 450 to 1,300 examinations per
1,000 population, with an average of 800 examinations
annually per 1.000 population for level I countries.
The number of diagnostic x-ray examinations isincreasing. according to the results of sequential
surveys in several countries.
17. From 1976 to 1980, the number of radiologicalexaminations performed in hospitals in Canada increased by approximately 2.7 million. Most types of
examinations increased in number. The examinations
that decreased in frequency over that time period were
those of the abdomen, breast and bronchus and thoserelated to obstetrics and gynaecology [Cl]. When the
total examinations were considered for 1980- 198 1. there
was an annual rate of approximately 1.000 medical x-ray
examinations per 1,000 population (Table 1). Additional data have been reported from the province ofManitoba [M3], where the number of examinations
reported per 1,000 population was 860 in 1974 and
840 in 1979.
18. In France in 1957, approximately 6.2 nlillion
radiographic examinations were performed. As of
1981. this number had risen to 35 million (835examinations per 1.000 population). The number ofvarious types of diagnostic radiologic examinations
performed in France in 1982 is given in Table 1 [B9].
Le Gales et al. [L8] report that in France in 1980
approximately 9.8 million chest screening examinations were performed. About 60% of these were
photofluorographic, 30% fluoroscopic, and the rest
radiographic. In addition to screening for tuberculosis.
there is also a well-defined radiologic screening
programme in France for detection of congenital hip
dysplasia. Bouvet et al. [B18] have reported that
3.4 million radiographies of the hip and pelvis \\ereperformed in 1982. Of these, 725,000 were carried out
on children of less than one year of age. The annual
birth rate in France is about 720,000.
19. In Italy in 1983, 744 medical x-ray examinations
were carried out per 1,000 population [PI]. Indovina
et al. [I91 indicate that mass screening in Italy resulted
in 4.3 million chest photofluorographies in 1974 and
3.0 million in 1980.
20. The frequency of diagnostic x-ray examinationsin Japan is made grea:er by the mass chest x-ray
examination campaigns and by an emphasis on
examinations of the abdomen and the gastro-intestinal

tract (Table 1). Kumanloto [K32] reported thar in
1980. 26.6 million (242 per 1,000 population) mass
chest x-ray examinations were performed. This number is considerably loirrer than the 33 million photofluorographic examinations performed in 1975 [HJ].
21. In the Netherlands in 1980, approximately
8.7 million examinations were perfornied [B6].
Approximately 40%, of examinations were of thechest; half of these were mass miniature radiography.
The total annual frequency was 648 per 1.000 population (Table 1).

27. A detailed report on the annual frequency andtype of examinations performed in Sorivay in 1980
and 1983 has been published [S3. S4]. The total
annual frequency for 1980 \vas 641 per 1.000 populaLion (Table I ).
23. According to estimates by Kudritsk et al. [K19.
K201, the n ~ ~ m b eofr x-ray procedures in the Russian
Soviet Federative Socialist Republic (RSFSR) during
1970-1980 increased from 138.5 to 185.8 million andtheir annual frequency from 1.065 to 1,339 per 1.000
population. During that decade, the mean annual
increase in the frequency of x-ray esaminations
remained constant at 2.3-2.4%. Somewhat lower
annual frequency rates have been reported for the
USSR by Vorobyev et al. [V7] and Nikitin [N9]. They
indicated that between 1963 and 1981. the number of
x-ray examinations increased by 21%. The ratio ofphotofluorographic t o radiographic and fluoroscopic
examinations increased substantially (Table 2). T h eannual frequency of various types of chest x-ray
examinations was reported per 1.000 population as
follows: photofluorography. 526; radiography, I 18;
and fl~~oroscopy,
149 [V7]. Similar figures have beenreported by both Neamiro et al. [N6] and Sikitin [hi91(Table 1). About one half of all x-ray examinations in
the USSR are chest photofluorography performed forprophylactic purposes.
24. An estimation of the annual frequency and typeof examinations performed in S p a ~ nin 1986 has been
made by Vano et a1 [V3]. The total annual frcquenc!
was 490 per 1.000 population (Table 1). The increment
bet\seen 1985 and 1986 was 2.5';;.
5 . Wall et ai. [W6] have indicated that the frequent!
of diagnostic examination5 in the United Kingdom in
1983 was 488 per 1.000 population (Table 1 ). This is no1
significantly different fronl the value of330 reported in
the UNSCEAR 1977 Report [US]. The annual increasein frequency for most types of examinations u.as
2-3qc.

76. Gro\+th of diagnostic radiological procedures in
the IJnitcd States appears to hatre been fairly rapid.
There has been a general increase in almost all typesof general radiographic examinations since 1964. The
rate of hospital-based examinations per 1.000 population was 370 in 1964. 400 in 1970 and 570 in 1980,\vhicIi is similar to the hospital x-ray examination rateof 650 per 1.000 estimated for Canada. The totalfrequency of medical x-ray examinations in the UnitedStates is 790 per 1.000 population [M28]. The increasein frequency of examinations in Canada and theUnited States is probably due to a number o i factors.
including. among others, a change in the age distribution of the population. The number of medical
diagnostic machincs per 1.000 population increased
from 0.5-7 in 1969 to 0.61 in 1981.
27. Zhang et al. [Z4] and Zhang [ZS] conducted 3.
survey of radiological services in Shangdong Province.
China. for the years 1976-1980, and this information
has also been included in Table I . The authors
reported that during this time the annual frequency of
examinations in rural areas increased by 77% (from146 to 259 examinations per 1.000 population), whilein urban areas the frequency was significantly higher
but had increased much less as a percentage of thetotal (from 577 examinations per 1,000 population in1976 to 7 10 in 1980, corresponding to a 23% increase).
Chest fluoroscopy accounted for more than 70% of all
examinations performed. chest radiography for only
2%. skeletal radiography for 6%. and special examinations for 4%. The authors also indicated that the
majority of chest fluoroscopy was for screening
purposes. Similar urban rates have been reported by
Sun et al. [S32], who indicated that the total annual
frequency of radiographic procedures in Beijing was
761 per 1,000 population, with chest fluoroscopy
accounting for 65% of all procedures. Approximately
90% of all x-ray equipment in China in 1980 was
fluoroscopic (i-e. about 70.000 fluoroscopic units).
Somewhat lower utilization rates (about 120 per 1.000
population) have been reported by Zhang [Z7] for theZhoukou region of Hunan Province, although the
distribution of types of examinations is similar to thatreported by other authors.
28. A discussion of diagnostic radiologic proceduresin the Islamic Republic of Iran in 1980 [S19] indicatesthat the estimated overall rate of diagnostic x-ray
procedures was 180 per 1.000 population. The authors
also suggested that the frequency of x-ray examinations in urban areas was higher than in rural areas andsmall towns. \virh the urban population receiving
approximately twice the national average.
29. Data regarding the number and frequency o i
x-ray examinations available from Turkey for 1977
[Y I] indicate that the annual frequency was about 80
examinations per 1.000 population.
30. The number of diagnostic radiological examinations performed in various Central and South Americancountries is difficult to ascertain, but some trends canbe indicated by the growth in the number of machines(Table 3). There has been an increase in the number ofradiodiagnostic machines in Argentina and Chile.
while in Costa Rica, Ecuador and klesico, the numberof units per 1.000 population has not increased.
31. By applying the estrapolation procedure described in paragraph 10, the number of diagnostic
x-ray examinations and machines on a world-widebasis may be estimated. The basic data used to makethese estimates for various levels of health care areshown in Table 4. From these values. the averageannual examination rate per 1.000 population and the

population per x-ray machine for each level of healthcare are derived from the data in Table 4 and areshown in Table 5. To the extent that populations.
numbers of x-ray machines and examinations haveincreased in direct proportion to one another since thesurveys took place, it uill be approximately valid toestimare current levels of practice from present world
population. The number of annual x-ray examinations
world-wide is thus estimated to be approximately
1.400 million. and the number of diagnostic medical
x-ray units. approximately 440,000. The number ofniedical x-ray examinations for the four levels of
health care are listed in Table 6. As might be expected,
the one quarter of the world's population i n countriesof health care level I receives three quarters of theexaminations. The average number of examinations
performed per year and per x-ray machine ranges
from 3.000 to 5,500 for all levels of health care.
32. Table 7 indicates that. of the diagnostic x-ray
examinations performed in some Latin Americancountries, chest examinations account for 22-50% andexaminations of the extremities for 72-36% of thetotal. This is fairly consistent with the data in Table 1.
ughich showed that in level 1 countries 32% of all
examinations were of the chest and 19% examinationsof the estremities. The Committee has reviewed
a\.ail;rble data over the past decade on the percentageof the total of diagnostic s-ray examinations accounted
for by each type of examination. This is shown in
Table 8 for three levels of health care. The maindifference appears to be that examinarions of theabdomen and digestive tract represent 16% of thetotal in level 1 countries but decrease to 13% in level I1
countries and to 6 5 in level 111 countries. At the sametime. there is an increase in the percentage of chest
examinations from level I countries to level 111
countries. I t is of interest that examinations of thehead and neck and urogenital examinations accountfor a fairly uniforni percentage regardless of the levelof health care.

33. As might be expected, the urban population
receives more x-ray examinations than the rural
population (Table 9). Similar findings have also beenreported by Cockshott [C7], who terms this the"capital city syndrome" even though the data are forurban areas in general and not just capital cities. In
effect. a segment of the population often receives a
disproportionately high number of examinations. This
disproportion is also evidenced by the data available
from China [S31, 241 and the Islamic Republic of Iran[S 191. Urban populations may receive two to 10 times
as many examinations per caput as rural populations.
34. Information on the historical trend in the annual
frequency of diagnostic examinations in various countries is summarized in Table 10. With the exception ofChina and Turkey, the countries are level of healthcare I. For these level I countries the annual growthrate for examinations from 1955 through 1983 ranged
from 0% to 10%. with an average of 3% over the
decade 1970-1980.
35. Dental radiography is the most common type of
diagnostic x-ray examination. In the UNSCEAR 1977

and 1982 Reports, the Committee reported data on
the annual frequency of these examinations in several
countries, but no data were available on trends. At
present, data indicating trends are available fromthree countries.

dental examination rate of 517 per 1,000 population.
No increase in intra-oral examinations had occurredby 1985; however, there was a small increase inpantomographic examinations, to I I million examinations.

36. The use of dental radiology in the United
Kingdom has been reported by Wall and Kendall[W3]. It is apparent from these data that there was amarked increase in the use of dental radiology from1963 t o the end of 1981 (Figure 11). The frequency ofdental x rays more than doubled between 1970 and
1983. In 1983, there were 9 million dental x-ray
examinations (I65 per 1.000 population). In 1981 mostwere intra-oral (6.7 million). but 150,000 were extraoral and 910,000 were pantomographic. The average
number of films per examination in 1981 was 1.8.

39. According to the UNSCEAR 1977 Report [U5],the number of single dental exposures per 1,000
population in Sweden in 1974 was 1,500. Preliminary
data from Sweden obtained for 1984-1985 [V2] indicatethat about 1.800 dental films were obtained per 1.000
population. In the United States. there has also been asubstantial increase in the frequency of dental x-ray
examinations per 1.000 population [MIO], although theincrease was not as rapid as in the United Kingdom[W3]. The number of dental x-ray examinations in
the United States increased from 67 n~illionin 1970 to
105 million in 1982. Exposures increased from 280
million to 380 million during the same period.
Between 1970 and 1982 in the United States theaverage annual compounded growth rate for examinations was 4.2%. The number of exposures (films)
increased at an average annual compounded growthrate of 3.4%. The number of exposures per patient
declined somewhat as pantomographic procedures
gradually replaced full-mouth series. In 1970, approximately 6% of all dental x-ray examinations were
pantonlographic, and this number had risen to 18%
by 1982. In 1982, the annual dental radiographic
examination rate was 456 per 1,000 population. Dental
x-ray machines increased from 98,000 in 1966 to
201,000 in 1981 [MIO].

YEAR

Figure II. Growth in the u s e of dental radiography in the
United Kingdom s i n c e 1963.
[W31

37. In Fra.nce in 1984, 27.5 million intra-oral films
and 1.76 million pantomographic films were taken[Bl I]. Between 600 and 1.200 examinations annually
were performed per machine.
38. In Japan, a survey carried out in 1976 [K9]indicated that the annual number of oral radiographic
films per caput in Hiroshima and Nagasaki ranged
from 0.8 t o 1.0. Exposure frequencies were approximately 1.5 times greater among the non-exposed
individuals than among the atomic bomb survivors.
According to Maruyama et al. [MI 11, who estimatedthe use of dental radiography in Japan in 1980. theannual number of exposures for intra-oral radiography
was 90 million (769 exposures per 1,000 population),with an average of 1.7 exposures per examination (435examinations per 1.000 population). Pantomographic
examinations were estimated to be 9.6 million (82 per
1.000 population). This represents a total annual

40. I t appears that there has been relatively rapid
growth in the number of dental x-ray examinations incountries of health care level I, ranging between 50 and
100% in the years 1970- 1980. While there has been someincrease in intra-oral dental x-ray examinations, thelargest increase has occurred in pantomographic
examinations. There has been growth not only in thenumber of examinations, but also in the number ofdental x-ray machines.
41. By applying the extrapolation procedure described in paragraph 10, the total number of dental
examinations performed world-wide for the various
levels of health care can be estimated. The basic datarequired were taken from published information andhave been collected in Table 11. Very limited data area~pailable for level I11 countries and no data are
available for level IV countries. The estimated total
number of procedures for each level of health careis shown in Table 12. Acccrding to this estimate.
340 million dental radiographic procedures are conducted annually.
B.

AGE AND SEX DISTRIBUTION
OF PATIENTS

32. Knowledge of the age and sex distribution of
those receiving examinations is important for evaluating the applicability of the collective effective dose
equivalent as a measure of detriment for medicat
radiation, as well as for assessing the geneticallysignificant dose.

43. Table 13 shows the percentage of the populationof various countries, grouped by age and sex, receiving
various examinations. Comparison for various examinations reveals some interesting differences between
countries.
4 . It'hile only 31% of [he p o p ~ ~ l a t i oofn the UnitedStates is 35 years o r older. these indiv~dualsreceive
51% of all the examinations: also, the 1 IF of the
population older than 65 receive 15% of ali theexaminations. In the Islamic Republic of Iran, uhere
only 16% of the population is over the age of 45,
aimost 5 0 5 of' all examinations are performed on
individuals under the age of 30 [S19]. In China. 44%
of chest examinations are performed on persons under:hc age of 30, whereas in Koru-ay, the United
Kingdom and the United States the comparable figure
i 10'7. Ifi general. the less developed a country. thejdunger the mean age of the popularion and the!,ounger the population exposed in diagnostic radiology.

In the course of three surveys carried out in the
L'SSR, Kudritsky et al. [K19. K t 0 1 analysed the
distribution of s-ray examinations and-ident~fiedsome
senera! regularities for various age groups in the
popuiatlon. The lowest frequency. observed in children
under 1.;. \vas 20-50% of the mean value for the entire
population. The frequency of x-ray examinations
increased gradually ~ i t ape.
h reaching a masiniun; forpcrbons between 10 and 59 years. for ~ v h o r ni i was 1.5
to t~ v times higher than the a\erage frequent:. . in thegroup aged 60 and above. the frequent! of x-ray
examinations \vas again somewhat iou~er. reachingle\,els ?i)%beiou the average.
45.

16. In most of the countries of health care ievel 1. the
x-ray examinations are almost equally divided bet~vesn
males and females, thc main i.sceptions being niamrnograms. cholscystograms and barium enemas. For thesessaniinations there is in most countries a clear kniale
predominance. In the Islamic Republic of iran. 63cl
ili all examinations are performed on males.
.-lithough age and ses differences of populations
receiving x-ray rxaniinations are presented in this,'..nncs. there has been nu attempt t o introduce any::.gc--cic3cndcnt correction factor in caicu1ati~:n of thecl Cec:i\ r dose cquivaicnt commitment. X prepo:.luerancc~ ! dand i l l persons in a population should~hcorer~call!reduce its risk o i long-term sffect5
compared to a population of woriters. On the otherk a n a , screening s-ra! examinations involving ~ n i l d r e nuould. by a similar comparison. substantialiy i.."crease
the innger term risk to a popuiation. At prese2i there
i. ,:er> little inlomiation 21-ailable on !he impact of:.?opIas~ic and non-neopixtic cilseases c?n rr?dlation;;sk coei'ficisn!~or upon reduction in l ~ f ~ s p a n .
4-.

'

1':

C. i.LiP.ACT 'jF SPECIALIZED TY T E S
OF ES.-\AIlXAT!OSS
48.

In the LNSCEAR 1977 and 1982 Rcpo;ts, theCommittee suggested that the increasing use of newer
techniques might decrease the radiological exposure of

the population. It was uncertain whether imaging
modalities that d o not utilize ionizing radiation (suchas ultrasound) would replace existing radiologic procedures o r simply add to the total number ofprocedures. Since 1982, magnetic resonance imaging
has also become available; in this technique. images
are generated by the induction of radiowaves in amagnetic field, and n o ionizing radiation is utilized.
At present. the main use of magnetic resonanceappears to be for brain and spinal cord imaging. but
no numerical data exist on the frequency o r availabilityof this technique.
19. Hinz et al. [H 141 and Schwarz et al. [ S 5 , S6, S7]
have examined the replacement of specific radiographic
examinations by sonography. Their reports cover the>ears 1977- 1982. The authors specifically considered
procedures related to the stomach, abdomen, gallbladder, pancreas a n d urinary system. In those areas,
there was a decrease of about 5070 in radiographic
examinations (Figure 111) and an increase of about
150% in sonographic examinations (Figure IV). Decreases of 10%. 2% and 46% were found in contrast
examinations of the small bowel, colon a n d gallbladder, respectively.
50. Pelvic imaging procedures were specifically considered. with the expectation that radiological examinations of the pelvis might have decreased as pelvic
ultrasound examinations increased. The data are ofliniited value. however, because most surveys include
x-ray exaniinations of the hip and pelvis in the same
category. While ultrasound might be expected to havesubstantially reduced the number of oral cholangior a m s , in the United States, at least, the marked
Increase in frequency of biliary ultrasound certainly
had not decreased their number, although it may havereached a plateau as from 1980. There has been a substantial increase in radionuclide hepatobiliary imaging.
\\ hile percutaneous cholangiography and intravenous
cholangiography have markedly declined [E6].

5i. .I\lthoueh there was a marked increase in echocardiography afid nuclear medicine cardiac studies in
the United States between 1972 and 1980 (Table 14).
the number of ini~asivecardiac contrast procedures
Iras substantially increased rather than decreased. Itiiia; be concluded that in developed countries ultrasl?und has repiaced some radiographic procedures inimaging o i the gallbladder. the kidneys and the foetus.

57. Data are available concerning the use of computerized tomography in several countries. In Japan,
11.4 million procedures (123 per 1,000 population)
were performed in 1979 [NlO, Nll]. Of the total,
about 7557r were computerized tomographic scans of
the head and :he remainder were computerized tomographic body scans. Over 00% were performed on
patients 35 years o r elder. Some related data are alsoavailable from the United States [E6]. Prior to !970
computrrized tomography and ultrasound procedures
tvere hardly used at ail. Table 15 shows that theedof the head
increase 111 c o ~ n p ~ ~ t e r i ztomography
coincides with a substanrial reduction in the numberof radionuclide brain scans being performed a n d

[Stcmach
Gailbladder
ERCP

KidneysFigure Ill. Changes as a function of time (1977-1982) i n the number of x-ray examinations of variousorgans in a University clinic in the Federal Republic of Germany. (ERCP = encoscopic retrograde cholangio
pancreatographyj.
[HI 41f7 (;eilbiadd~r
Pancreas
Kidneys
Total

Figure IV.

Changes as a functlon o l time (1977-1982) i n the number of sonographic examinations of various organs
In a University clinic in the Federal Republlc of Germany.
[HI41

that, during the same period, pneumo-encephalograms
became extremely rare.
53. Evens et al. [E3, E4, E5. E6] and Hughes [H31]examined trends in the use of computerized tomography in the United States during 1981-1983. Total
scans increased from 2.337.000 in 1981 to 4.303.000 in
1983. Cranial scans accounted for 75% of suchprocedures in 1981 but decreased to 63% in 1983.
During the same period. computerized tomographyscans of the spine increased from 3% to 1 0 5 andother body scans increased from 22% to 27%. However.
the rate of increase in the use of computerized
tomography slowed markedly with the percentage
increase over the previous year being 53% from 1981
to 1982 and 2 1 % from 1982 to 1983.
54. Imaging procedures of the abdomen are difficult toevaluate since many computerized tomographic examinations of the abdomen and ultrasound examinations
are done for retroperitoneal pathology. The increasinguse of abdominal ultrasound and computerized tomography may have decreased the number of ordinary
x-ray examinations of the abdomen being performedin the United States between 1980 and 1983 [E6].
Whether this is a real finding or sinlply due todifferent reporting of the two surveys is unknown.
Computerized tomography has decreased the need forsome arteriograms [BZ, K7, WIZ], but in general there
has been a net increase in examinations utilizing
relatively iarge amounts of ionizing radiation. Anotherinteresting question is whether computerized tomography of the lumbar spine has partially replaced
myelography. In the United States the frequency of
myelography examinations has continued to increase inspite of increasing computerized tomographic examinations of the spine.
55. Another particularly important trend is that of
mammography. Table 16 indicates the significant
increase of mammography examinations per 1.000
female population. At present. the rate in the UnitedStates is slightly greater than 10 per 1,000 females
annually.
56. In the past decade there has been a rapid
expansion of both digital and interventional technologies. Digital technology in this context refers to
the recording of transmitted photons on an image
intensifier or other such receptor rather than on film.
This process allows computer manipulation of theimages. This technology has found widespread use invascular radiology, but it can also be used in otherexaminations. Interventional technology refers to anumber of techniques in which radiology is used to
guide the radiologist or other physician in a semisurgical diagnostic or therapeutic procedure. Examples
of such procedures are placement of drainage catheters.
needle biopsy of various lesions, catheter placement
for infusion of pharmaceuticals, and balloon catheter
placement for occlusion or dilatation of blood vessels.
Most of these procedures require lengthy periods offluoroscopy and may result in high absorbed doses tothe patient as well as to the operator. Data on thefrequency of such procedures are not available at this
time.

D.

EXPOSURE AND ABSORBED DOSE

57. The distribution of exposure or absorbed dose ina patient as a result of a diagnostic x-ray examination
depends upon (a) the amount of incident radiation;(b) the location and direction of the incident beam;and (c) the quality and attenuation of the radiation in
the body. The amount of incident radiation depends
upon exposure at skin entrance and the size of theradiation field. Exposure for an examination is sometimes reported free-in-air (i.e., without the bodypresent) and sometimes as skin surface exposure (i.e..
with the body there). Alternatively, the absorbed dosein soft t~ssueat the surface may be reported. The ratioof the exposure on the body to exposure free-in-air for
examinations t h a ~contribute significantly to the radiation dose is approximately 1.2 to 1.4. Some authors
have reported results in terms of energy deposited in
the total body or in a given organ rather than in termsof average energy absorbed per unit mass. It would be
worthwhile to unify methods of expression of patient
exposure and dosimetry.
58. While the average absorbed dose in a given
organ of the body depends on all the factors listed
above, some consolidations are possible when considering relative distribution of absorbed dose in the
body. If the physical characteristics of the beam (tube
potential, tube current. radiation field size. locationand filtration) are the same for a series of esposures,the relative absorbed dose distribution is independentof the amount of incident radiation. Approaimate but
adequate constancy is also obtained for a small rangeof patient sizes for a particular type of exarnination.
While the exposure at the body surface of adults for agiven type of examination may range over a factor ofup to 40 (Figure V) [U9]. the relative absorbed dose isusually considered to be adequately constant so thatthe effective dose equivalent for a given type andprojection of an examination is proportional to the
exposure or absorbed dose of the incident radiation. I tshould be noted, however, that relative absorbed dose
distributions change so that a different numerical
proportionality is obtained for children and infants
than for adults.
59. In the UNSCEAR 1977 Report [U3], typical skindoses in the primary beam for various examinations
were given. More recently, data on trends andvariability of exposures in the United States havebecome available from the Nationwide Evaluation of
X-ray Trends (NEXT) programme [U9]. In this programme, exposure is measured for five projections using
specified geometry and measured free-in-air. Histograms for composite data for the years 1973-1980,
shown in Figure V,indicate a rather wide distribution ofsuch exposures. Very similar data for 1975-1985 areavailable from the NEXT programme in Canada [C2]
Italy [I I]. With the advent of rare-earth screens andfaster film-screen combinations, one might expect thatthe mean exposure at skin entrance would be decreasing.
However, data from the United States suggest that as of
1983. in spite of technological advances, there has been
little reduction in average exposure [U9]. Therefore, one
is led to conclude that world wide, skin doses have not

30- CERVICAL SPIIIE , A/P

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Number o f surveys: 865

Number o f surveys: 1177

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200

400

600

800

o

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EXPOSURE AT SKIN ENTRANCE (mR)307

THORP.CIC SPINE, A/P

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Nunber o f surveys: 288

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EXPOSURE AT SKIN ENTRANCE

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Humber o f surveys: 310

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EXPOSURE AT SKIN ENTRANCE

3 2

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1500

EXPOSURE AT SKIN EIITRANCE

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2000

(mR)

EXPOSURE AT SKIN ENTRANCE

301

ABDOWEN KUB. A/P

3C7

V)

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U
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P

(mR)

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LL

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N u d e r o f surveys: 484

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80

EXPOSURE AT SKIN ENTRANCERETROGRADE PYELOGW , A/P
Number o f surveys: 752

V)

Number o f surveys: 3655

W
Z

0

0

a

1

W

D-

0
EXPOSURE AT SKIN ENTRANCE
Figure V.

(mR)

EXFOSURE AT SKIN ENTRAIICE(mR)

EXPOSURE AT SKIN ENTRANCE

Exposure at skin entrance (ESE) for various examinations (mR).(Exposure determined as "free-in-air"):mean exposure value).
[u91

changed significantly from those identified in the
UNSCEAR 1977 Report.
60. F o r purposes of this Annex. in order to be able
to compare results from different studies. exposures
measured free-in-air have been converted to skin
exposure using a backscatter correction factor of 1.3.
The skin exposures were then converted to skin dose
equivalent utilizing an absorbed dose t o exposure
conversion factor of I rad per roentgen o r I centigray
per roentgen. Mean skin doses in the primary beamfor various diagnostic x-ray examinations have beenmeasured in Canada, Italy, Poland. United Kingdom
a n d the United States (Table 17). Skin doses were
measured by placing thermoluminescent dosimeters(TLDs) on the skin surface of 1,340 patients during
22 types of diagnostic radiographic examinations in(mRj(arrow refers to

Beijing. China [J4]. These results are not significantly
different from results in other countries. Mean skindoses for five common diagnostic examinations in the
United Kingdom have been reported by Harrison[H2]. These data indicate a n approximately tenfold
range in dose within one country. with almost all of
the distributions showing a long tail that extends into
the upper range of doses. Absorbed doses reported fora given examination also differ significantly between
countries.
61. In addition to actual measurements a n d surveys
made of doses received from radiological examinations. simpler methods have been described involving
the use of nomograms to estimate exposure o rabsorbed dose from machine parameters. Veitch et al.
[V6] investigated the use of nomograms for estimatingthe exposure to the skin of a patient from three-phaseequipment. Substantial work had been done years ago
on single-phase equipment [S22, M241. More recently,
Edmonds [El] described a simple and rapid method
for calculating patient skin doses based on peakvoltage, current, source skin distance a n d filtration. In
fact. the method provides a quick estimate of exposure.
although it may overestimate the dose for three-phase
x-ray equipment by a factor of nearly 4 [S12]. A
nomogram for estimating skin doses in x-ray diagnostic
examinations has also been published [Wl].
62. Absorbed doses in various organs are needed inorder to calculate the effective dose equivalent. The
organs of interest include the thyroid, bone marrow,the lungs, the female breast and the gonads. A Monte
Carlo computer technique and a mathematicallydescribable anthropomorphic phantom have beendeveloped and can be utilized to calculate tissue-air
ratios for selected organs v 4 , R8]. Drexler et al. [DS],Jones [J 101 and Kramer [K 163 calculated organ doses
for x-ray diagnosis utilizing Monte Carlo methods forboth male and female phantoms designed according to
ICRP reference persons. By utilizing these techniques,
one can derive mean absorbed doses in a number oforgans, normalized to unit exposure measured free-inair under different conditions of beam quality andfield size. These provide information for thyroid, bonemarrow, lung, female breast and gonads. Williams
et al. [ W l q constructed three-dimensional phantoms
using computer tomographic data from patients,
which allows very accurate calculations of absorbed
dose in organs.
63. Monte Carlo calculations of organ doses take
into account only the primary radiation and radiation
scattered within the patient. The scattered radiationa n d leakage radiation from the diagnostic source
assembly, as well as other stray radiation. is usually
not included. When theaorgan of interest is within theuseful beam. stray radiation is not likely to accountfor more than 1% of the organ dose. However, when
the organ of interest is at least several centimetres
outside the useful beam, neglecting the contribution
from the stray radiation may result in underestimatingorgan dose by as much as 25-5096 [B5]. T o accountfor this, international [I31 and national [D4] standards
required for equipment restrict the dose rate outside
the beam to 1 per hour and require efficient collimation.
64. It is much more difficult to calculate organ doses
when fluoroscopy is utilized. The reason for this isthat automatic brightness controls are often used for
fluoroscopic examinations, and the exposure rate andbeam quality change as the beam is moved. Thus.
even when exposure parameters are known andexposure times recorded, the confidence limits on theabsorbed doses from fluoroscopy are larger than thosefrom radiography. T o overcome this difficulty (at least
partially), area exposure product meters can be used
1141.
65. Fluoroscopic examinations also present otherunique problems due t o the continuous changes inbeam direction. length of examination time. field sizeand positioning in the course of examination. During
standard radiographic procedures, matters such as theincident exposure side of the patient are quite straightforward, but during fluoroscopic examinations theincident and exit sides of the patient are oftenchanging. The length of time that a fluoroscopic
procedure takes, and thus the resulting absorbed dose.
varies widely depending on the complexity of theexamination, the co-operation of the patient and theskill of the operator of the equipment. Harrison [HZ]
has reported total fluoroscopic screening times used in
the United Kingdom for a barium meal examination.
The average time was 146 seconds, but the range was
1-620 seconds. Rowley et al. [R9] have also reported
the median exposure times for various fluoroscopic
examinations in local areas of England. They report
the following: barium swallow, 180 seconds; barium
meal. 180 seconds; and barium enema. 150 seconds.
Little difference in time was noted in relation to thesex of the patient. however, males consistently received
higher absorbed doses due to larger body size. Longer
screening times of 337 seconds for a barium enema
and 240 seconds for a barium meal are reported by
Pandovani [PI] in Italy. Maccia et al. [MI. M2] havereported on the use of fluoroscopy in France: theirmean fluoroscopic times for various examinations areshown in Table 18. It is of interest that fluoroscopy isused to position or centre patients in 2550% of
examinations that are usually considered radiographic
examinations.
66. In general, fluoroscopic procedures result inmuch higher doses t o the individual patient than mostother types of standard radiographic examinations.
For this reason. the achievable dose reductions couldin principle be larger. Several authors investigated theeffect of variation in equipment design on patient
dose. Tole [T4] reported that fluoroscopic machineswith the tube placed over the table often give
substantially higher organ doses (particularly t o themale gonads) than machines with the tube under thetable. This occurs because for most fluoroscopic
examinations the patient is in the supine position o rfacing forward and the male gonads are relatively
anterior in location and closer t o the x-ray tube a s well
as being unshielded. Zeck and Young [Z3] pointed out
the very high radiation levels that can be associatedwith C-arm fluoroscopes. In general. the minimum
source-skin distance for a C-arm device is 30 cm.
Spacers are usually used to maintain this distance but
are sometimes removed and not replaced. If thepatient is then positioned close to the tube, theentrance skin exposure rates will be much higher thanusually calculated.
67. Fluoroscopy times accompanying coronary angi*
grams are usually about 10-20 minutes [A3]. Cascade
et al. [C5] have recently reported exposures andfluoroscopy times for the relatively new technique of
percutaneous transluminal coronary angioplasty. In
this technique. fluoroscopy is utilized to monitor the
progress of a balloon catheter introduced in order todilate one or more stenotic coronary arteries. When
only one stenosis was dilated, the fluoroscopy timewas 36 minutes and skin dose was 0.5 Sv. When twostenoses were dilated, the fluoroscopy time was
51 minutes and patient skin dose was 1.0 Sv. Similar
data have been reported by Faulkner [F2].
68. While technical parameters affecting absorbed
dose are relatively well known in some countries, thetechnical factors used for specific examinations areoften unknown. Large portions of the population
receive uncertain but possibly large doses. For example.
Hussain [H22] surveyed x-ray installations in Bangladesh and reported that the current and voltage
indicators on many machines did not work at all andthat over 40% of machines either had no collimator orthat i t was not functional. Thus the exposure at skinsurface, field size and location of the centre of the
field are generally not known. Under these conditions,calculations of absorbed doses to various organs or
determination of effective dose equivalent are virtually
impossible.
69. Similar conditions were described for India by
Bhargava [B16]. In a survey of diagnostic x-ray
installations. 20% of the machines produced excessive
exposure during fluoroscopy and showed excessive
leakage from the tube housing. In 20% of themachines neither cones nor collimators were used tocontrol the beam size. Das et al. [Dl], reporting on
exposure to the patient's skin for various examinationsin India, indicated that a fluoroscopic examination of
the chest results in a skin dose of approximately
120 mSv.
70. In Beijing. China, Sun [S32] has measured skin
exposure during 2,395 fluoroscopic chest examinations
at 44 hospitals, and he reports mean skin doses ofabout 10 mSv. Wu et al. [W23] have reported on skin
exposures in 370 patients who had various uppergastro-intestinal examinations in China. For most
examinations. the skin doses were 50-180 mSv. Weng
and Wu [W 1 I] measured skin exposures for 30 patientsin China having cardiac catheterization. The skin dosein the field was 100 mSv for the fluoroscopy alone andan additional 260 mSv for the radiographic portion.
All these measurements were made on the skin surface
utilizing thermoluminescent dosimeters. Because theuse of fluoroscopy is still widespread in developing
countries where data are scanty, the absorbed dose to
the population may be estimated only very roughly.
71. Absorbed dose from mass screening esaminations continues to be of interest to the Committee.
The average skin dose equivalent in the field for amass chest x-ray examination in Japan in 1980 was
1.5 mSv for adults and about 0.8 mSv for children[K22]. In many countries mass chest screening is often
performed with photofluorography. Bengtsson et al.
[B13] have indicated that the average dose to thebreast from such examinations is about 2.0 mSv.
almost as high as the absorbed dose from a mammogram. The effective dose equivalent for chest x-ray
mass screening in France has been reported to be
0.07 mSv for radiography, 0.32 mSv for photofluorography and 0.98mSv for fluoroscopy [LS]. The
collective effective dose equivalent for this practice inFrance in 1980 was about 4,500 man Sv. In Japan.
mass screening of the stomach is often performed

utilizing photofluorography. Maruyama et al. [h113]
have indicated that 4.1 million such examinations
were performed in Japan in 1980: this represents
about one examination per 30 people. The collective
effective dose equivalent from this practice wasestimated to be about 16.000 man Sv.
72. Knowledge of absorbed doses to the uterus,
embrvo and foetus is useful in situations where apregnant woman has been exposed to diagnostic
x rays. Glaze [G4] and Drexler [D5] described acomputer-assisted procedure for estimating both patient
exposure and foetal dose from radiographic examinations. The dose incurred in paediatric x-ray examinations is also of interest since a large portion of thechild's body is often included in the primary beam[N2]. Morris [M36] calculated doses in .Australia forpatients in the age group 2-4 years and for those under
the age of two. Similar Monte Carlo calculations arealso ;vailable to assess the doses from paediatric x-ray
examinations to the total body. bone marrow, thyroid,
lungs, ovaries and testes [G5]. For typical examinations in paediatric x-ray diagnosis. Williams et al.
[W16] and Zankl et al. [Z2] used a Monte Carlo code
to calculate the doses to a baby and child phantom
constructed from tomographic data.
73. Radiation doses to neonates requiring intensive
care were examined in the United Kingdom by
Robinson et al. [R5]. These babies are of particularconcern since they may receive larger numbers ofradiographs than adults. and the treatments often
include barium examinations and computerized tomography scans. The marrow dose from all examinations
was found to vary approximately inversely with birthweight. In addition, children with lower birth weightreceived more examinations (Table 19). Gustafsson et al.
[G8, G9] have examined the relationship between bodyweight and energy imparted for children of various ages
and body sizes. The energy imparted was less per
kilogram for the older and larger children. There was,however, substantial variation in energy absorbed forchildren of the same weight. This variation was
ascribed to technical factors, such as beam collimation.
Gustafsson also discussed the relationship of beam
direction to dose. Performing a chest radiograph in
the posterior/anterior projection causes relatively larger
dose to the bone marrow than when i t is done in theanterior/posterior projection. The latter projection,
however, delivers a larger dose to the breast andthyroid. Lcibovic et al. [L4] reported on paediatricangiocardiography procedures, which provide thehighest exposure per examination of any diagnostic
paediatric procedure. The authors noted that as muchas 25% of the exposure from such examinations wascontributed by manual test exposures to adjust thetechnique. The average dose rate to the skin in theposterior/anterior projection for cine filming was
0.7 mSv per second and in the lateral projection
2.1 mSv per second. Fluoroscopy exposure rates wereapproximately 5% of this.
74. Of special interest is the dose received by thebreast in mammography. Bates [B3] has reported onskin exposures in 27 screening centres in the UnitedStates. The results showed that a substantial reduction

in exposures and tissue dose was achieved during thecourse of this project. Rimondi [R3] has reported
doses from mammography in Italy. He indicated that.
even with the same type of x-ray apparatus and filmscreen combination, very different exposure values
were obtained, ranging over two orders of magnitude.
Skin doses in this survey ranged from 2 to 220 mSv.
The mid-plane doses were from 0.18 to 1 1.1 mSv.
75. Hammerstein [HI] and Stanton et al. [S26]reported doses measured in a breast phantom designed
to simulate a breast with a uniform mixture of equalamounts of adipose and glandular tissue. Similar
results have been reported by Panzer [P5] from astudy of 170 facilities in the Federal Republic of
Germany. Average glandular doses for non-screen
films ranged from 5 to 35 mSv with a median value of
16 mSv. and for screen-film systems from 0.8 to
19 mSv with a median value of 6.6 mSv. Zuur [Z12]reported similar dose values from 12 institutions in the
Netherlands, ranging from 1.0 to 8.8 mSv.
76. Sato [S2] carried out a survey o n the radiographic
technique and frequency of mammography in Japan. Of
the 75 institutions surveyed. 45 utilized intensifying
screens and film for mammography, 30 used a nonscreen system and 20 did not have any special apparatus
for mammography. There were approximately 2.9 exposures per examination, or 1.5 exposures per breast.
77. Gannon [GZ] reviewed the equipment performance at 28 mammography centres in the UnitedStates. In this study the actual peak voltage wasmeasured and compared to the dial reading on thexerox-mammography-type machines. In most cases
the desired peak voltage was between 36 and 50 kVp.
In only one case was the measured peak voltage thatwhich was actually desired; in some instances the peakvoltage differed by as much as 7 kV from that set on
the machine. Such differences significantly affectimage quality. The two-view (mediolateral and craniocaudal) mid-line (3 cm depth) dose measured in aphantom ranged from 2.5 to 1 1.6 mSv.
78. The use of grids in mammography has been
advocated to improve image quality and to reduce
scattered radiation incident on the image receptor.
Kirkpatrick [K I I] measured the effect of such grids onpatient dose. He showed that. although there was again in image quality, absorbed doses were approxim a ~ e l ythree times higher, unless there was a significant
change in exposure parameters. Whether the improvement in image quality was worth the increased dose was
not indicated, although the use of grids is usually
restricted to circumstances where the thickness of thecompressed breast exceeds 5 cm.
79. Measurement of absorbed dose from the newer
technologies has also been a matter of concern. In the
UNSCEAR 1982 Report, the large amount of literature
reviewed indicated that the dose to the skin from acomputerized tomography scan could be as high as
560 mSv, although in clinical practice the absorbed
doses were mostly around 60 mSv. The dose distribution within the body from computerized tomography
is markedlv different from that from conventional

radiography. In most radiography, the dose is highest
on the incident side and lowest on the exit point; inmost computerized tomography. the dose is lowest at
the centre of the body section studied. The effective
dose equivalent and absorbed dose from various computerized tomography procedures have been derived
by Stieve [S3 I].
80. The x-ray beam of a computerized tomography
unit is usually highly collimated. but the eye may be ino r near the primary beam on scans of the brain o rface. and the dose to the eye is of particular interestfor radiation protection purposes. Lund et al. [L6]
and Kronholz [K 181 indicated. for brain computerized
tomography, that although slice thickness and patient
position have some effect on the absorbed dose in thelens of the eye. the greatest doses are those received
when the scan is done with the gantry angled
downwards in relation to the orbito-meatal (from theouter corner of the eye to the external ear canal) line.
In this circumstance the eye is included in the primarybeam. This positioning factor caused the dose to thelens of the eye to increase by a factor of 2-4 compared
to standard orbito-meatal scans. Doses to the lens of
the eye from cranial computerized tomography are in
the range of the absorbed dose from other neuroradiological procedures. Isherwood et al. [I51 indicatedabsorbed doses to the lens as follows: orbital hypocycloidal tomography, I20 mSv; petrous bone tomography, 100 mSv; cerebral angiography. 50-100 mSv:
pneumo-encephalography, 20 mSv; and skull examination, 15 mSv. Panzer [P4] collected dose values
from 120 facilities in the Federal Republic of Germany.
Preliminary results show a large variation in the dosevalues (free-in-air) on the axis of rotation. from 10 to
200 mSv per slice. with a median value of 30 mSv. By
calculations using Monte Carlo methods. the dose
(free-in-air) can be converted into organ doses [D5].
81. The radiation doses to variorls organs for thetypes of computerized tomography scanners used inJapan have been published by Nishizawa et al. [NIO.
N 1 I] and are given in Table 20. While the exact values
depend upon the technique and the type of scanner,the values presented are in general consistent withthose reported by other authors [BI, C8, E7, E8, G3.
15, M20, M25, S 10. S 1 1 , S24, S35, W 121. McCrohan etal. [ M 161 surveyed 250 computerized tomographysystems in the United States to determine the radiationdose from a head scan. For the typical adult scan theabsorbed dose was 22-68 mSv; doses varied by afactor of two for the same manufacturer and model ofmachine. Beck et al. [B4] have devised a Monte Carlomodel for absorbed dose calculations in computerized
tomograph y.
82. There is a trade-off between image noise andradiation dose [TS]. All calculations used by thecomputer to construct the image are limited by thestatistical distribution of the detected photons. Several
attempts have been made to reduce the dose throughvarious technical modifications. Dose reduction canbe achieved by radiating and collecting data only
during a portion of the scan cycle. Oppenheim [ 0 5 ]found that artifacts caused the method to be of limited
usefulness. More recently, Stanton et al. [S27] devised

a method that collects data over the entire scan but
exposes the region of interest to a higher dose thanother anatomical structures within the scan volume.
This is accomplished through the use of a variable
thickness filter: dose peak reductions of up to 80% areclaimed for head scans. ,Moseley et al. [M37] discussed
various methods of reducing radiation dose in the
management of intracranial lesions that are clinicallyfollowed by use of computerized tomography, butthey did not report any quantitative dose reduction
factor. McCullough [.M23] suggested that the performance of each computerized tomography scanner
be specified and checked in order to ensure a typicallevel of performance and to provide a baseline value
for a programme of quality assurance. Parameters
tested usually include slice geometry, patient dosage,
artifactual behaviour and contrast detail performance.
83. Digital medical radiographic systems are now
becoming available in most developed countries. The
contrast resolution of such instrumentation is limited
primarily by quantum mottle. Rimkus et al. [R4]indicated that the number of meaningful levels of greythat are imaged will significantly affect the radiation
dose. For example. if 128 meaningful visual shades ofgrey o n an image require a dose of 17 mSv to thepatient, simply raising the level of contrast resolution
to 256 shades of grey will increase the dose by a factorof 5-10. However, since such contrast resolution israrely needed for diagnosis. this is an area where
unnecessary dose can be avoided.
84. The frequency of dental examinations was discussed in section I.A. Data on dental exposures areavailable from the Nationwide Evaluation of X-ray
Trends (NEXT) survey in Canada [C2]. For a dental
bite-wing posterior examination, a dose a t skin entrance
was recorded with a minimum of0.56 mSv, a maximumof 43 mSv and a mean of 4.7 mSv. For periapicalexaminations, the maximum was 2.6 mSv, the minimum was 0.57 mSv and the mean was 2.2 mSv(standard error 1.1 mSv). Results from 200 dental
facilities in the Federal Republic of Germany werereported by Panzer [P6]. Entrance doses for examinations of a molar tooth ranged from 2.5 to 45 mSv witha median value of 8.5 mSv. Comparison with earlier
results (1970) showed a remarkable decrease in entrance
doses.
85. In Japan [MI I], the annual per caput doses fordental radiography were estimated to be 0.09 Sv(genetically significant dose) and 13 Sv (mean bonemarrow dose). Iwai [I61 compared absorbed doses to
the gonads and to bone marrow for both intra-oral
and panoramic dental examinations and reported thetotal risk for intra-oral examinations to be lower thanthe dose for the less frequent panoramic examinations.
86. Radiation doses from dental x-ray examinations
were discussed in detail in the UNSCEAR 1982
Report [U5]. The radiation exposure for dental films
may be decreasing somewhat. The Nationwide Evaluation of X-ray Trends (NEXT) programme in the
United States [U9] indicated that the mean dose atskin entrance from dental bite-wing posterior films
was 9.1 mSv in 1973 and 4.3 mSv in 1981. There wasan increase in the dose from pantomographic examinations, from 0.3 mSv in 1973 to 0.8 mSv in 1981.
87. Weighted dose equivalents in the United Kingdom have been calculated by Wall et al. [W3]. These
values are 20 pSv for intra-oral examinations consistingof two films, 3 0 p S v for extra-oral examinations
consisting of two films and 80 pSv for one pantomographic film. They estimated the collective weighted
dose equivalent to the population of the United
Kingdom to be 212 man Sv. The mean dose equivalent
to various organs per dental examination is shown in
Table 2 1.
88. Pellerin et al. [PI01 reported on exposures inboth phantoms and patients for various types ofdental examinations in France. The intra-oral exposure
was the most commonly used and delivered a maximum
dose to the skin of about 15 mGy. The pantomographic view gives a picture of the entire dentition but
delivers a dose of approximately 10 mSv to three intracranial "hot spots". Tingey [T2] has re-emphasized theneed for quality control procedures to reduce theexposure factors and also to avert repeat examinations.
89. Dosimetry in panoramic examinations has also
been studied in the Soviet Union by Trunov et al. [T8]and Kirko [KlO] utilizing thermoluminescent dosimetry
and anthropomorphic phantoms. The radiation dose
was 15-20pSv per film for examinations of the upper
jaw and 25-30 pSv per film for examinations of the lower
jaw. The thyroid doses were 40-180pSv and gonadal
doses were 13- 150 pSv.
90. Hayami [HI21 recently devised a Monte Carlocomputer programme t o estimate exposure t o the head
and thyroid for panoramic intra-oral x-ray tube
radiography. With 55 kV (kilovolts) and 0.5 mAs(milliampere seconds), the energy imparted for a routine
examination was 2.1 m J to the head from eachexposureof the mandible and maxiila, about 8.5 p J to the thyroidfrom a mandibular radiograph and 1.7 p J to the thyroidfrom a maxillary radiograph.

E.

CAUSES O F DOSE VARIATION A N D
POSSIBILITIES FOR DOSE REDUCTION

9 1. Some possibilities for dose reduction are found by
examining the causes of variation in dose for a given
examination. Dose reduction cannot be taken as anultimate goal in medical radiation since the images
generated must have sufficient informational content to
be of diagnostic value. An underexposed radiographthat cannot be interpreted is of no value to the patienteven though the absorbed dose is low. Many aspects ofimage quality and its assurance were discussed at aseminar organized by the Commission of the European
Communities [C 101. The actual assessment of priorities
and analysis of cost versus benefit in this regard isbeyond the scope of this Annex. Such analyses would behighly dependent on the availability of operating
equipment a n d the knowledge of health care practitioners of a given country. There certainly are, however,some simple and low cost methods that can be used to
substantially reduce absorbed dose. Russell [RlO] haspresented one form of methodology that could be
utilized for such assessments.
92. Wall et al. [W3] have discussed a number of thefactors involved in dose reduction. There have been
many changes in diagnostic radiology techniques overthe past 20 years, many of which might be expected tohave had a significant effect on patient doses. The trend
towards faster films and the advent of highly sensitive
rare-earth screens should have resulted in lower
exposures per radiograph. However, the adoption of
rare-earth screens has been very slow; for example. only
five out of 21 hospitals surveyed in the United Kingdom[W4] used them at all, and then only for obstetricexamination or casualty work. High cost and poor
spatial resolution due to quantum mottle are the mostcommon reasons for their poor acceptance. Use of suchrare earth screens appears to be higher in Italy [Cl I].
The use of new materials (such as carbon fibre) for
construction of table tops, grids a n d film cassettes has
the potential to reduce patient dose by 30-50% [H191.
Dose reductions in pelvimetry have been marked in the
United Kingdom and the United Stares, as a result of
fewer examinations. feuer projections a n d the increased
use of ultrasound.
93. An appropriate combination of radiography andfluoroscopy can result in dose reduction, particularly
for examinations of the gastro-intestinal tract [S28].
Fluoroscopic screening times have not decreased [W4],and therefore the hoped for dose reduction owing to theincreasing use of image intensifiers has not materialized
in the United Kingdom. In some departments automaticbrightness controls are allowing examinations to be
conducted in ambient light rather than in a darkened
room. This increases the absorbed dose to the patient.
Maccia et al. [MI] have reported the percentage of thecollective effective dose equivalent in France that iscontributed by fluoroscopy (Table 22). It appears thatabout 5.000 man Sv are contributed by the use offluoroscopy to position patients prior to routine film
radiography.
94. The effect of gonadal shielding upon gonadal dose
has been discussed by Poretti [P 141. Such shielding isparticularly effective if the gonads are in the useful
beam. Although gonadal shields are relatively inexpensive and easy to use, their use is not widespread. Wallet al. [ ~ 4 have]reported that in the United Kingdom
gonadal shielding was used for males only 35% of thetinic for hip and upper femur examinations. 26% of thetime for lumbar spine examinations and 15% of the time
for pelvis examinations.
95. One area that has received some attention. withresultant dose reduction, concerns the tailoring of thesize and shape of the beam to the area of interest andto the film size [ C l I]. Many older medical x-ray
machines have a circular beam, while the film isgenerally rectangular. Johnson [J7] point out thatcollimation of the primary beam has been a n evolutionary process, whose stages are. at first. circularcones, then, variable rectangular collimators and,
finally. positive beam limitation. In general, rectangular collimators are almost as good as positive beam
limitation, but with circular cones there is almost

twice as much radiation given as needed (Figure VI).
The shift from circular to rectangular collimation forchest radiographs in the United States is shown in
Figure VII and the resultant reduction in the amountof x rays utilized is shown in Figure VIII. The
situation is somewhat different with fluoroscopy. In
this case the collimators are usually rectangular while
the image intensifier is circular. If the operator wishes
to use the whole of the circular image, there is about
25% additional and unnecessary radiation.
96. Use of lower voltage for a given study will
require higher entrance surface doses. Contento et al.
[Cl 11 have reported that in France softer x-ray spectra
are used for a given examination than in Great Britain
and Italy. The voltage and radiation output variationof s-ray machines have been studied by Henshaw[ H 131 and Pauly [P9]. They observed variations fromthe desired voltage. ranging from 5% to 20% or more
and averaging approximately 10%. Belletti et al. [B7]

WastedNeededCircularbeam
Figure VI.

Rectangularbeam

Positivebeam
limitation

Mean ratio of beam area to film area for chert
x rays in the Unlted Slates, 1977-1983.

1571

1-r

1964

Rectangularcircular

1968

1972

1976

1980

YEAR
Figure VII.

Trend in beam shape for chest x rays in the Unlted
States, 1964-1983.
(~71

possible exception of ultrasonography. none of theother techniques has had any impact on the use of
mammography.
Needed

1964

1968

1972

1976

1980

YEAR
Figure V111.

Mean ratio of beam area to film area in the UnitedStates, 1964-1983.

[J7l

analysed the causes of repeat films. One of the moresignificant results was again the discrepancy between
measured and selected peak voltage. Ten to 15 percent of the machines examined were found to have a
10'3 difference between the set and measured valuesof peak voltage. Of all films that were spoiled, over
50% had been under- or over-exposed. Most spoilage
was due to variations in the voltage produced byunstable generators, incorrect choice of either voltage
or current, or malfunctions in film processing.
97. Practical recommendations to improve radiation protection in clinical mammography have been
published [N3]. Breast compression is particularly
important, not only to improve contrast and diminish
motion unsharpness but also to reduce absorbed dose.
Firm conipression of the breast can reduce theabsorbed dose by 5 5 0 % while resulting in images of
equal clinical usefulness. From an analysis of datafrom some 60 mammography installations throughout
the United States [S17], i t was concluded that the
choice between xerographic and film-screen receptors
is the most critical factor affecting breast exposure,
followed by the choice of half-value layer and target
material. Film-screen receptors without grids result in
two to five times less absorbed dose than xcromammography. Panzer et al. [P5] have indicated thateven a distinct increase in image deteclor sensitivity byswitching to film-screen combinations did not always
correspond to a comparable decrease in dose to thepatient. Part of the reason for this may be that doses
to obtain optimal images for various film-screen
combinations for mammography vary by up to afactor of 2 [KIZ].

98. Breast phantoms have been utilized to assess
absorbed dose from various imaging systems. Computation of absorbed dose is of course dependent onbreast size, adiposity etc.. but for analysis of detriment
one needs to know the average size and composition of
the breast in the population of interest. At the present
time, research continues into alternative methods forbreast imaging, such as thermography, ultrasonography. computerized tomography, magnetic resonanceimaging and digital x-ray mammography. With the

99. The effect of patient size on dose variation
received in diagnostic radiology has been studied byMaillie [M4]. The thickness of the patient is more
important at low potential (voltage), and the averageabsorbed dose from radiographs taken on individualsof various thicknesses may differ by as much as afactor of 4 or 5. As the peak voltage is raised, thevariation due to body thickness is reduced to a factorof 2. Of course the thickness of the irradiated part is
not the only factor that influences the doses to variousorgans: for example, a taller person will have someorgans farther displaced from the useful x-ray beam
than a shorter person. Increasing radiation quality(voltage) reduces entrance skin dose but increases
absorbed dose to organs at depth. The percentage
reduction in effective dose equivalent is much lessthan the corresponding reduction in entrance skindose. This potential method of dose reduction should
be weighed against possible disadvantages such as
reduced image contrast.
100. Dosimetric methodology can be a significant
cause of reported absorbed dose variation. Padovani[PI] has recently shown some limitations of the Monte
Carlo methods when they are used to determine
absorbed doses to various organs as a result of
medical practice. Monte Carlo methods assume goodpractice (e.g.. excellent collimation). In his survey innorth-east Italy he found major differences between
the absorbed dose to organs calculated by Monte
Carlo methods and that measured by thermoluminescent dosimeters. Actual testicular doses for specificexaminations were higher, by factors of 4-50, thanMonte Carlo calculations would suggest. Similarfindings were reported for absorbed doses to thebreast and thyroid. These findings are probably due tothe organs being near the field of interest and poor
collimation being utilized.
101. Stieve et al. [S30] and others have repeatedlyemphasized that training in the use, calibration andquality assurance of x-ray equipment is an essential
part of any dose reduction programme. In many, if
not most, countries. over one half of x-ray examinations are performed by persons with little or no formal
training. Even in well-developed countries, many nonradiologist physicians perform x-ray examinations
though they have little or no formal training in uses ofs rais or of x-ray protection. Proper theoretical andpractical training of all persons involved in the
medical uses of radiation is one of the most importantways to achieve dose reduction [S30. V5]. Cohen [C9]attempted to generalize and assess the benefits ofquality assurance programmes. He estimated that in adeveloped country a quality assurance programme
would lead to a reduction of 50% in the per caput
whole-body dose equivalent from diagnostic radiology.
from approximately 1.0 mSv per year to 0.5 mSv per
year.
102. Some of the possible methods of dose reduction
and their quoted dose reduction factors are summarized

in Table 23. The largest dose reduction factors occur
as a result of switching from chest fluoroscopy andphotofluorography to chest radiography. with dose
reduction factors of about 20 and 5, respectively. Itshould be mentioned that economic and other factors
often dictate what equipment is available to be used.
Certainly, in the corr-ect clinical setting, chest fluoroscopy is preferable to no chest x-ray at all. The simplest
and least expensive methods that do work and that dooffer modest dose reductions are (a) installation ofcollimation on machines; (b) added beam filtration:(c) the use of gonadal and thyroidal shielding; and(d) proper film processing. The judicious use ofradiographic examinations and the elimination of
non-productive examinations, ~vhichare another areafor potential dose reduction. have been the topic ofseveral recent WHO reports [W 19, W221. Discussions
have centred on the efficacy of screening or preoperative chest x-rays, skull films after minimal headtrauma. pre-employment examinations of the lumbar
spine or the chest. and examinations of the genitourinary system and sinuses in children [G8, G9].
F.

tically significant dose surveys have been performed
and u.ert: summarized in both the UNSCEAR 1977
Report [U4] and the UNSCEAR 1982 Report [U5].
Since then. Sohrabpour et al. [S19] reported that in
the Islamic Republic of Iran the genetically significant
dose in 1980 was estimated to be 93 pSv. with themale and female contributions being 57% and 43%.
respectively. In the province of Manitoba. Canada. thegenetically significant dose was calcillated in 1979 by
MacEwan [M3] to be 760 rcSv.
104. Kumamoto [ K E ] indicated that the geneticallysignificant dose from mass chest x-ray examinations inJapan in 1980 was 0.17pSv. The genetically significant
dose due to computerized tomographic esaminationsin Japan in 1979 was estimated to be 1.1 pSv.
105. In France in 1981 the annual genetically significant dose was estimated to be 0.29 mSv [BIO]. This
represents a 64% increase from 1957. Table 24 also
shows that the genetically significant dose for females
is more than twice that of males (0.20 mSv versus
0.09 mSv). Examinations of the pelvis/hip and inrravenous urography contributed almost 60% of thegenetically significant dose. Fluoroscopy accounted
for only 105. ivhile x-ray examinations contributed
90%.

MEASURES O F RISK

103. The genetically significant dose (GSD) for a
population has been used as a measure of the genetic
detriment to be expected from a practice. It is definedas "the dose which. if given to every member of the
population. would produce the same genetic detrimentas the actual doses received by the various individuals."
In some countries, such as China, gonadal doses and
GSD may be greater than had been previously
estimated. Apparently fluoroscopy is used in someprovinces of China to check for the presence andlocation of intra-uterine contraceptive devices. Zheng
et al. [ZIO] have reported that mean skin doses forsuch examinations measured with TLDs was 8 mSv.
In other countries there are problems in determining
gonadal doses because of the lack of good data
regarding the presence of collimation. .As was mentioned earlier. in India and Bangladesh 20-40% of themachines have no functional collimation. Many gene-106. Figure IX indicates a very high gonadal dose inFrench children under one year, which is apparently due
to mandatory screening for hip dysplasia. The average
dose equivalent to the female and male gonads fromvarious examinations is shown in Tables 25 and 26,
respectively.
107. Genetically significant doses in various countries
are shown in Figure X and Table 27. It is clear fromthese data that the average gonadal dose (as well asskin dose) often varies between countries by a factorof 3 or more. Poretti [PI41 has reported on both
gonadal dose and genetically significant dose in
Switzerland, where the GSD rose from 0.19 mSv in1971 to 0.23 mSv in 1978. He also calculated the doseto the gonads with and without gonadal shielding foroFemales

Males
1.4

-

A

>

--

1.2-

1.0-

(> 60 years)

Wg 0.8 Y,0.6 -0.4 0.2 -00Figure IX.

I

I

I

5

15

25

I

I

35
45
AGE ( y e a r s )

I

I

I

55

65

75

Average annual dose equivalents to the gonads in France.
tBl01

500

-

110. Stochastic risk estimates of various types forJapan have been published by Hashizume [H3. H41.
Annual per caput bone marrow dose in Switzerland
was reported by Poretti [PI41 as 0.63 mSv in both
197 1 and 1978. The average active mean bone marrowdose to the United States population from radiologicalprocedures in 1980 was about 1.3 mSv if the methodof Shleien et al. [S9] is used for calculation. This
compares with 0.83 mSv in 1964 and 1.0 mSv in 1970.
Estimates of mean per caput marrow doses are very
dependent upon the modelling parameters utilized.
While the relative contribution by examination typedoes not change appreciably according to the method,
the numerical quantity obtained is significantly different[R8, S9].

2 400 -

>

W

0
'A
0

& 300

u

-

U
I=
Z

;
; ZOO I3

>
1
I

<

U

2

z

100 -

W

0

0Flgure X.

Annual genetically slgnllicant dose in various
counlrles.
[a101

four common examinations. Gonadal shielding reduced
gonadal doses by a factor of 2-10, depending upon theexamination and on the distance of the gonads fromthe area of interest being radiographed.

111. Beentjes et al. [B6] reported that the annual per
caput "somatic effective dose" in 1980 in the Netherlands from diagnostic radiology was about 0.5 mSv
and that the average somatic dose per examination
was approximately 0.8 mSv. The somatic effective
dose was defined as the uniform whole-body dose thatwould cause the same somatic risk as the actual nonuniform dose from the x-ray examinations.
112. A somatic dose index has also been proposed108. According to estimates made by Kudritsky etal. [K19, K20] for the Russian Soviet Federative
Socialist Republic. the trend is towards a gradualincrease in the mean per caput gonadal dose. During
1970-1980. this increased by nearly 50%. probably
owing to an increase in the number of special
examinations and in examinations of the digestiveorgans and the osteo-articular system. The value of thegenetically significant dose also changed. I t increased by
0.06 mSv during the decade, mainly as a consequenceof examinations involving radiation of the pelvic
region (Table 28).
109. The genetically significant dose includes only
absorbed dose that can be expected to affect theprogeny; it does not take into account the somaticeffects in the exposed population. Examples of thelimitations of the genetically significant dose concept
in practice have been given by Kaul et al. [K3]. In
cases of a simultaneous increase in both the rate of
examinations involving ionizing radiation in a given
population and the number of alternative procedures
applied in paediatric examinations in the same population, the genetically significant dose may lead to amisinterpretation of population exposure. Kaul et al.
[K4] have therefore recommended that when sources ofradiation exposure are being compared, the geneticallysignificant dose should be indicated with estimates ofsomatic radiation exposure. The authors also pointed
out significant limitations in the use of the geneticallysignificant dose, particularly in countries where theage distribution changes with time. Under suchcircumstances the genetically significant dose alone isan unreliable indicator of the state and trend of
medical radiation exposure; comparative evaluationsof mean radiation exposure in different populations
will also be of limited value. The latter point will
become more important over the next several decades,
when the world's population is expected to age
markedly.

[L7] that utilizes individual organ doses weighted
according to sex-dependent factors for the relative
radiation risk and not weighted for the gonads. Kaul
et al. [K4] compared the ICRP weighting factors andthe modifications occurring when the genetic risk isneglected: their conclusion is that excluding thegenetic risk has an effect less than the uncertainty
involved in the calculation of the absorbed dose to anorgan.
113. Calculations of effective dose equivalent fromdiagnostic procedures must include an analysis of thedose distribution within the body. The dose equivalent
in an organ. T. for a given radiographic examinationmust be obtained by the formula:where k is the type of view involved in the esamination. nk is the number of films for the view k; DT.i isthe average absorbed dose in the organ for view k.
and Q is the quality factor. Q is 1.0 for x rays used indiagnostic radiology.
114. The effective dose equivalent, Ht. for an
examination of type 1 is obtained from the following
equation:
HE.I = wTHT.I(7)
where w7 is the weighting factor for each organ given
in ICRP Publication 26 [12]. One rnain difficulty
encountered by most authors has been i n selection ofthe "remainder" organs as required by the ICRP
definition, which may change from one examination
to the next. The selections. however, are not consistent.
Some potential solutions to this problem have beensuggested by many groups, e.g.. Stavitsky et al. [S29].
In many published articles in which effective dose
equivalents have been reported, the methods forchoosing remainder organs are not given.

115. Calculations of the effective dose equivalent fordifferent types of examinations in Poland in 1976 andin Japan in 1979 were included in the UNSCEAR
1982 Report [U5]. Since that time, there has been one
additional publication from Poland [Jl], in which theeffective dose equivalent per adult in 1976 wasestimated to be about 1.7 mSv. Vano et al. [V4]reported an annual per caput dose equivalent of
0.8 mSv for Spain and a collective effective dose
equivalent of 32,500 man Sv.
116. Reported annual effective dose equivalents fordifferent examinations are shown in Table 29. Values
generally range from 0.1 to 10 mSv.
117. From diagnostic x-ray examinations of the
population in France in 1982, the collective effective
dose equivalent was 86,000 man Sv. or an annual per
caput effective dose equivalent of 1.6 mSv [BI]. In
France the examination with the largest percentage
contribution to the collective effective dose equivalentis intravenous urography, whereas in other countries,
such as Japan and the United States, barium enemas
a n d upper gastro-intestinal examinations play a larger
role. Even from one highly developed country toanother. the per caput effective dose equivalent mayvary by up ti a factor of 5. Some of these differences
are certainly due to the number of examinations andto technical differences (beam quality, collimationetc.). In addition, hourever, Benedittini et al. [BIO]
indicate that there have been significant differences in
the calculations of effective dose equivalents in specificorgans by various authors. Benedittini et al. [Bll]reported on the absorbed doses to patients fromdental radiology in France in 1984. The collective
effective dose equivalent was estimated as 2,000 man Sv
a n d the per caput effective dose equivalent as 0.037 mSv.
Although pantomographic examinations accounted
for only 6% of the total number of examinations, theirhigher absorbed dose caused them to contribute 29%of the collective effective dose equivalent. Nikitin et al.
[N8. N9] a n d Vorobyev et al. [V7] reported a percaput effective dose equivalent of about 1.5 mSv for
the USSR. In 1981 the collective effective dose
equivalent was estimated at about 400.000 man Sv.
118. I t should be noted parenthetically that it isunconlmon for a person to receive the "average" percaput effecti~ge dose equivalent calculated for thecountry in which he is living. Some authors havereported their findings as collective effective dose
equivalents. Once this quantity has been derived for agiven country, it can be divided by the population to
obtain the per caput effective dose equivalent. Although
in highly developed countries the frequency of diagnostic medical examinations may approach one
examination per person per year, it is unlikely that
more than 2 5 5 0 % of people will actually have one
examination in a given year. In less developed
countries (health care levels 11-IV), the situation iseven more extreme, with perhaps only 1 person in
1,000 actually receiving an examination in a given year.
Under such circumstances the person undergoing theexamination would receive 1,000 times the average percaput effective dose equivalent or genetically significant dose, while 999 persons would receive no dose.

119. The energy imparted during a radiographic
procedure has been suggested as an approach toestimating radiation risk. This method ignores thedifferent sensitivities of individual body organs andcalculates the energy imparted during a given procedure. It is attractive since it avoids the problem ofcalculating mean radiation doses to large organs [P8].
Bengtsson [B 121 and Shrimpton [S 13, S 141 havealready reported a reasonable correlation between themean energy imparted and radiological risk. Over arange of two orders of magnitude in dose, meanenergy imparted correlates with the quantity effective
dose equivalent within factors of 2 o r 3 [S14]. There isalso a reasonable correlation between the energy
imparted and the somatic effective dose. However,
Huda [H 151 has examined this approach with respect
to computerized tomography scanning and concluded
that it can lead t o large errors in patient risk
estimates.
120. Various other weighting factors can be utilized
in an attempt to represent the impact of medical
radiology in a more accurate fashion than can be donewith the effective dose equivalent. As a first approximation, one could take the effective dose equivalent
for the mean age of the population having a certain
examination, multiply this by the specific rate for thatexamination and by absorbed dose. A second approximation would use the total age-specific weighted dose
equivalent but would not use organ-specific risk
factors. A third approximation could take sex into
account as well by assuming a standard ratio of males tofemales having a specific examination. The greatest precision would be obtained by a fourth approximation
which would apply age-specific and sex-specific weighting factors for each organ. Such weighting factors would
be multiplied by the known dose to each organ foreach examination type as well as each examination
rate.
121. For a population of both sexes and a certain
age distribution. the ICRP risk coefficient is normallyutilized. T o calculate the expected number of deleterious
effects. n, after irradiation, Bengtsson et al. [B14] use
the formula(3)
n = RHEN = RS
where R is the risk coefficient, N is the number ofindividuals in the group and S is the collective
effective dose equivalent. If age and sex are to betaken into consideration, one can have groups i,-,.
Additionally for each organ or tissue T. the risk in agiven tissue per unit dose equivalent can be defined.
One can then apply a series of risk factors for eachtissue as a function of that tissue and age and sex of
the individual. This would be expressed as r , ~ .T h eprobability of deleterious health effects in a given
tissue would be expressed as the product of r i and~ HE
in that tissue. Thc probability of a deleterious effect inall tissues of a given individual in an age group would
be given by
nI = r r i T H T i(4)T

Similarly, the expected number of deleterious effects
for all persons in group i would be given aswhere r i is~ the risk coefficient in tissue T. HI, is thedose equivalent in tissue T and Ni is the number ofindividuals in group i. In a similar fashion. theexpected number of deleterious effects produced byexaminations of type J in the total population would
be given byn~ = f(6)

countries. As was pointed out earlier. Zhang [Z4]estimated that in China chest fluoroscopy accounts for
70% of all examinations performed and that !heassociated absorbed dose is at least 15 times higher thanthat for chest radiography. It must be remembered inthis connection that China accounts for approximately
20% of the world population.

This could also be written as125. Faced with these difficulties. the Committee has
decided to calculate upper and lower limits for theeffective dose equivalent and genetically significant
dose for medical diagnostic radiography ivorid-wide(Table 32). Calculations were performed by two
methods, Method 1 is based on the frequency ot'
examinations at various levels of de\~elopmrint.and it
assumes that the average doses for a given examination are comparable in countries of differing levels of
health care. This method leads to a lower limit ofapproximately 1.8 10" man Sv for the effective dose
equivalent and of 0.5 lob man Sv for the collective
genetically significant dose equivalent. Method 2
assumes that although examinations are less frequentin countries of health care levels 11. 111 and IV, theabsorbed doses are 10 to 20 times higher than in level I
countries primarily because of the extensive use offluoroscopy and poorly calibrated machines. Thismethod yields upper lirnits of 5 lo0 man Sv for thecollective effective dose equivalenr and 1.5 lob man Sv
for the genetically significant collecti\,e dose.

P~T~T~J~IJ

n , = S; R
where S; is the collective reference population dose for
examination J. rIT/R could also be termed "f factor"
rather than weighting factor.
122. This appears to be quite precise in theory
although. as was pointed out earlier. there are many
uncertainties in the exposure factors, the absorbed
dose t o various organs and, particularly. the rissuespecific risk factors in the presence of disease. The risk
factors used for this model were derived for continuous
exposure of a working population and not for
exposures received over a short time. Therefore, therisk derived is at best semi-quantitative. In a population with a very skewed age distribution, the use ofcollective effective dose equivzlents may lead to an
overestimation of detriment by a factor of between
1.5 and 3 [J8, M291. The applicability of the conceptsof effective dose equivalent and risk-weighted dose
equivalent quantities to medical radiation have been
examined by Drexler [D6], Ivanov [IS] and Kramer[K 141.

G. WORLD-WIDE ESTIMATES O F DOSESFROM DIAGNOSTIC X-RAY EXAMINATIONS
123. In spite of the difficulties mentioned in thepreceding secrion, an attempt is made here to derive
per caput and collective effective dose equivalentsfrom diagnostic x-ray examinations. The reported
annual per caput doses for countries having various
levels of health care are shown in Table 30. For healthcare level I countries. the effecrive dose equivalent andgenetically significant dose agree reasonably well. In
these countries the average per caput efr'ective dose
equivalent is approximately 1 n1Sv and the geneticallysignificant dose is approximately 0.3 mSv. An analysis
of diagnostic x-ray examination frequencies and contributions to absorbed doses in countries of healthcare level I is shown in Table 31. In previous
UNSCEAR Reports it was been assumed that in lessdeveloped countries the collective effective dose equivalent would be lower. perhaps by an order ofmagnitude, due to the lesser frequency of radiologicalexaminations. This would appear to be true according
to literature on genetically significant dose in countriesof health care levels I1 and 111. However, most ofthese reports have not included fluoroscopy.
124. If the frequency of examinations is one tenth ofthat reported for countries of health care level I, and if
fluoroscopy accounts for 30-70% of the total examinations. then the effective dose equivalent and geneticallysignificant dose for countries of health care levels 11,
TI1 and IV may in fact be comparable to those of level I

196. Data on the effective dose equivalent andgenetically significant dose from dental radiography
are uncvcn and come only from countries of level ofhealth care I. Since it appears that fltloroscopy is notwidely used for dental purposes, one might assume
that the per caput and collective doses for countries ofhealth care levels 11, 111 and IV are related predominantly to the frequency of examinations. The
genetically significant dose from dental radiography inlevel I countries appears to be about 1/10.000 of thatfrom medical diagnostic radiography. Estimations of
the per caput and ~vorldwide effective dose equivalentand gcnctically sipificant dose for dental radiography
are shown in Table 33. The annual collective eifective
dose equivalent world-wide from dental radiograph! isestimatsci to be about 17,000 man Sv with an annual
genetically significant dose of 0.04 jrSv.

H. OCCUPATIONAL EXPOSURE
FROM DIAGNOSTIC RADIOGRAPHY
127. In the UNSCEAR 1982 Report [U5],occupational exposure was considered in a separate .4nnex.
For this report. however, occupational exposures are
considered along with the associated sources o rpractices. Evaluation of occupational exposures frommedical radiation usage is complicared by the fact thatthe radiation usually comes from point sources close
10 the workers. Thus, the exposures are significantly
non-uniform over the body because of the inverse
square law as well as attenuation in the body. The
effective dose equivalent cannot be easily inferredfrom one personal dosimeter on an individual, andthis is especially true if the dosimeter is not in theprimar!, radiation fields striking the body. To makematters more complicated, the dos~metersare notalways worn in the same position. although generally
they are \(lorn at the waist or neck. Often the recorded
data do not indicate \itherher the uorkrr wore thedosimeter inside or outside a protective lead apron.
For these reasons i t is very difficult to utilize average
dose as measured by a dosimeter arid to correct i t toeffective dose equivalent. Other difficulties are thatminimum detectable levels vary as a function of
dosimeter type and that the administrative decisions
on whether to record the minimum detectable dose as
zero or some other value are often arbitrary. Suchdecisions can hzve a major impact on estimation of
the cullecti\~eocc~ipationaldose. since in occupational
exposure irom medical radiation, a large percentage ofworkers recei1.e doses at or near the n~inimum
detectable level [D7]. The best that can be said is that
fur rad~stion qualities used for diagnostic \-rayprocedures. the dosimeter usuall) measures a valuethat is 2-4 times higher than the effective dose
equivalent [Jl?. %139]. if a protective apron is notworn and i f the exposure is relatively uniform. I f a
protective apron is worn and the personal dosimeter isplaced on the outside (3s is practice in the UnitedStates). then reported doses could be as much as 10 to
20 times higher than the effective dose equii~alent.
128. A3 was discussed in the UNSCEAR 1982
Report [U5]. another ma-ior complicating factor isaccurate job classification of workers. While there is
not usuallv a problem in differentiating between
diagnostic radiologists and radiographers (technicians).
the rota1 number of workers in the field is sometimes
expanded to include nurses, porters. aides. dark-room
technicians etc.. which can lead to erroneous caiculations when determining mean annual ~ndividualdose.
hiany of these latter ivorkers are not usually monitored
since they usually receive very l o ~ vdoses. The number ofunfi~onitoredpersons w h o occasionally perform x-ray
euaminat~onsis unknown but is probably quite large.
even in developed countries. The exact umber ofmonitored workers engaged in performing diagnostic
x-rac exam~nations varies ividely from collntry tocountry. The range appears to be one monitored
worker per 150-750 examinations annuall) [ U J . U5,
w171.
129. Data on occu~ationai doses received frommedical x-ray diagno;is are given in Table 34. In
general. the average annual effective dose equivalents
range from 0.1 to 3 mSv annually above natural
background for radiologists and technologists. The
dose distribution among the population o i workers is
r~larkedly skewed. with a long tail of higher doses
received by very few individuals: The highest exposuresto radiologists, technologists and nurses occur during
fluoroscopic procedures. Ameil et al. [AZ, A31 andTryhus et al. [T7] have reviewed the literature on
absorbed dose to the radiologist during angiographic
examinations. Doses were reported as follows: eyes.
0.01-0.5 mSv; thyroid, 0.03-0.5 mSv; waist (inside leadapron). O.UZ mSv; and hands, 0.05-1 mSv. Absorbed
doses can be higher by a factor of 10 or more if theradiologist makes a manual injection (staying in theroom during filming) or if there is an over-the-table

x-ray tube. Gustafsson et al. [GI01 have es:imatedthat the effective dose equivalent to the radiologist
performing angiography is about 0.03 mSv per
examination.
130. It had been previously assumed by the Committee that lower estimates for occupational exposureswould be appropriate for countries that had a lower
frequency of exarninations. This may not be the case.
however. as is indicated by the recent data publishedby Wang [N1lO] and Zhang [Z9] for China, where
average annual occupational doses for diagnostic
medical workers are reported to be between 2.2 and4.3 mSv. This figure is two to 10 times higher than thecomparable figure in some countries of health carelevel I. There has. however. been remarkable progressin China (health care level 11) in reducing theoccupational doses over the past several decades.
Wrang [Wlo] reports that the average annual dose todiagnostic x-ray workers was 55.5 mSv before 1957.
8.7 mSv from 1957 to 1966 and 2.2 mSv from 1967 to
19d0. The reason the doses still remain higher than incountries of health care level I is probably the extreme
use of fluoroscopy and the lack of image intensification systems. The situation may be significantly worse
in countries of levels of health care 111 and IV.
Hussain [H22] reported on 31 1 x-ray installations in
Bangladesh (level IV) and found that a majority of theinstallations had no shielded control booth. leadaprons or gloves. As was mentioned previously,
almost one half of the machines had no functional
collimation. I n this Xnnex it will be conservatively
assumed that the collective effective dose equivalent
per million population is the same in countries ofvarious levels of health care.
131. Information on occupational doses incurred asa result of dental radiography is very limited: however.
the average annual doses are relatively IOU (Table 34),
ranging from 0.03- mSv to 0.4 mSv annually in countries of health care level I. Dental practlce generally
contributes less than 1 % to the collective effective
dose equivalent from all occupational sources.

I.

FUTURE TRENDS IN DIAGNOSTIC
RADIOGRAPHY

132. I t is instructive to postulate the future medical
uses of radiation and the extent of their applicationand to examine potential areas of concern over the
next 15 years. There is little doubt that, world-wide.
the frequency and total number of procedures involving
medical radiation will increase substantially [04. U6).
There are three main reasons for this. First. there is
the aging of the population, particularly in Europe.
The Federal Republic of Germany. Switzerland, Italy
and Greece are expected to have more than 20% of
their populations over the age of 60 by the year 2000.
The USSR and several other countries are expected toexperience the same phenomenon. but to a lesser
degree. As was indicated earlier, the older populationaccounts for a disproportionate number of medical
diagnostic and radionuclide exarninations as well asradiotherapy procedures.

133. The world's population is experiencing a marked
contraction in the percentage of population between
0 and 30 years and a marked expansion in thepercentage above the age of 30 [U6]. From 1950 to1980, changes in the age distributions varied among
the regions of the world. For example, the median ageof the populations of Europe and the Soviet Union
increased by about four years between 1950 and 1980
and that of Africa decreased by about 1.5 years. The
median age for other regions decreased by about 2
years until the early 1970s and then began increasing.
and i t is now at the same level as it was in 1950.
In contrast with past trends. the future is expected to
be characterized by an aging of populations in all
regions: the median age of the world population is
expected to increase from 22.6 years in 1980 to 26.1
years in the year 2000 and to 30.8 years in the year
2025. The oldest populations in 2025 will be in
Europe, East Asia. and Northern America. The
youngest populations will be in Africa and Latin
America. with median ages of 22.8 and 27.4 years,
respectively.
134. Second, the total number of examinations will
also undoubtedly increase simply as a result of population increase. The world's population was 2.5 billion
in 1950 and 4.4 billion in 1980; it is projected to be
6.1 billion in 2000 and 8.2 billion in 2025. Even if theannual per caput effective dose equivalent and genetically significant dose remained the same, the collective doses would increase by over 60%. from 1988 to
2025.
135. The population of the world had an annual
growth rate of 1.7% in 1985. Throughout the nineteenth century and the first half of the twentiethcentury its annual growth rate was 0.5-0.8%. In thelate 1960s, the world's population was growing at
about 2% annually, and projections are that thegrowth rate will fall to 1.5% by the year 2000 and to
1% by 2025. It is important to note that while the rateof growth is declining, the annual increment to the
tvorld's population is increasing. The annual increment to the world's population in 1950 was 46 million,
and in 1980 i t was about 75 million. The annual
increment is expected to peak at approximately
88 million near the end of the century and then decline
somewhat by 2025. .Although the global growth rate
appears to be on the decline. there is marked
difference between the more developed and lessdeveloped regions of the world. In the det7eloped
regions population is growing at an annual rate of
0.6%; in the less developed countries, it is growing at
approximately 2%. As a consequence, the proportionof the world's population living in the less developed
countries is expected to increase steadily.
136. Demographic trends also vary substantiallyfrom one part of the world to another. There is a
rapid growth of the population in Africa. which iscurrently increasing at 3% per year and is expected tocontinue to increase at this rate until the end of the
century. In 1950, the population of Africa accounted
for about 8.7% of the total. but in 2025 it is expectedto account for 19% of the total. Another rapidly
growing area is Latin America, which has a growthrate of'2.5'70 per year or higher. Latin America's shareof the total world population grew from 6.5% to 8.2%
between 1950 and 1980, and by 2025 its share is
expected to be 10.6%.
137. Third, the number and frequency of examinations will increase as a result of growing urbanization.
At present. 41% of the population is classed as urban;
in the year 2025, this percentage is expected to rise to65%. As already discussed, urban populations have amuch higher frequency of x-ray or radionuclide
examinations than rural populations, the difference
being an order of magnitude or more. If 50% of theulorld's population were urbanized by the year 2000. if
the population aged as predicted and if the total
population were 6 billion, the per caput doses andcollective doses could be 50-100!'i higher than atpresent.
138. There are some countering factors In theseprojections. As the population ages, the assumed
detriment would have less time to be expressed. andthe use of an age-weighted dose equivalent H-ould
assume more importance. In simpler terms, although
the number and frequency of examinations would
increase, an older population would have less time to
be at risk for the induction of stochastic effects.
Moreover, in addition to depending on age. thegenetically significant dose also depends on the
reproduction rate. The gross reproduction rate inmost developed countries is expected to remain fairly
steady in the period 1980-2000, but i t is decreasing indeveloping countries. This will be an additional factor
to take into account when calculating the geneticallysignificant dose. Overall. i t can be assumed that thegenetically significant dose will increase, but not as
rapidly as the per caput or collective effective dose
equivalent.

11. DIAGNOSTIC USE O FRADIOPHARMACEUTICALSA.

FREQUENCY A N D TRENDS

139. Since the UNSCEAR 1982 Report. the Committee has obtained information from various countries
on the number of in v ~ v odiagnostic nuclear medicine
examinations performed. This information is collected
in Table 35. The frequency of all nuclear medicine
examinations for countries of health care level I is in
the range of two to 49 examinations per 1,000 population and for China (level 11) it is 0.6 examinations
per 1.000 population. Only in vivo diagnostic nuclear
procedures are being considered in this chapter.
140. Malmstrom [M6, M7, M8, M9] reported statistics
concerning nuclear medicine examinations in Sweden
for the years 1979 through 1982. The total number
ranged between 125,000 and 130.000 examinations
annually (15 per 1,000 population).
141. The number of diagnostic nuclear medicine
studies in the United Kingdom in 1982 was reported
to be about 380,000. 84% of which were imaging

examinations. Bone scans were the most often performed procedure, although cardiac studies had increased 150-fold since 1973. Technetium-99m was theradionuclide used in 75% of the administrations, while
iodine-131 was used in only 5%.

between countries but also within countries. The
reasons for such variation are not known, but they
may include training of the staff and, possibly.
sensitivity of equipment.

142. The number of diagnostic nuclear medicine
procedures performed in the United Stares in different
years is shown in Table 36. This Table documents the
progressive increase in the frequency of diagnostic
nuclear medicine procedures, both in absolute terms
and per uni: population. There was a rather sharp
increase between 1970 and 1976, a plateau between
1976 and 1980 and another increase until 1982, with asharp rise in cardiovascular and hepatobiliary imaging
procedures. The only category in tvhich a decline isevident is radionuclide brain scans. Similar trends
have been reported in Denmark by Ennow [E2].
143. The percentage of each type of diagnostic
nuclear medicine procedure may differ substantiallyfrom country to country. Table 37 shows that while
thyroid imaging constitutes a large percentage ofprocedures in many Latin American countries, it
constitutes only 9% of diagnostic radionuclide procedures in the United States, a variation that was also
noticed and commented on in the UNSCEAR 1977
Rcport [U4]. A survey of radionuclide thyroid studies
in the United States was reported by Parker et al. [P7],
who identified substantial intra-country variation inmethodology and radionuclide use. Technetium-99m
pertechnetate was used for 54% of all thyroid scans
and iodine- 13 I was used for only 9% of them. The restof the thyroid scans were done with iodine-123. In
summary, administered activity for a given examination varies by as much as a factor of 4 not only

1

I

100

Figure XI.

500

144. The extrapolation procedure described in paragraph 10. which has been used to estimate world-wide
medical diagnostic x-ray activity. can also be used toestimate nuclear medicine activity. A broad correlation
exists between population per physician and annual
nuclear medicine examinations per 1,000 population.
There is also a strong relationship between population
per physician and the population per scanner or
gamma camera (Figure XI). The source terms andtrends utilized to obtain averages for various levels of
health care are shown in Tables 38 and 39. Estimatesof annual examinations per 1,000 population forvarious levels of health care are shown in Table 40.
It is estimated that there are approximately 24,000
gamma cameras or scanners world-wide and thatapproximately 24 million in vivo diagnostic radionuclide
examinations are performed annually (Table 4 1). The
number and type of nuclear medicine imaging devices
in the United Kingdom have been reported by Wall
[WS, W9]. The number of gamma cameras has
markedly increased since 1974, while the number ofrectilinear scanners has decreased.

B.

AGE AND SEX DISTRIBUTIONO F PATIENTS

145. For calculations of the genetically significant
dose and related quantities it is necessary to know orassume the age and sex distribution of patients
undergoing nuclear medicine procedures. Results of

I

I

I

lOC0
5000
10000
POPULA-IOIi PER PHYSICIAN

I

50000

I

100000

Correlatlon between population per physlclan and populatlon per
nuclear rnedlclne mechlne In various countriea.

[M281

surveys performed in Poland in 1981 [S25] and theUnited States in 1980 [UlO] are given in Table 42.
About one third of the procedures in the United States
are performed in persons over the age of 64 andapproximately 70% of the procedures are performedin persons over the age of 35. This is true for mostprocedures, with the exception of thyroid and renal
imaging procedures. In Poland the population receiving
nuclear medicine examinations of all types is muchyounger.
C.

IMPACT O F NEW TECHNOLOGIES

136. The impact of the new techniques has alreadybeen discussed briefly in section I.C. particularly the
impact o f computerized tomography on radionuclide
brain scans and the possible impact of cardiovascular
nuclear medicine procedures on invasive contrast
studies. In view of the relatively high absorbed dose to
the thyroid delivered in the course of examinations
with iodine-131, many countries have begun to utilize
either iodine-123 or technetium-99m pertechnetate.
Unfortunately, iodine-123 is both difficult to obtaina n d expensive. The number of thyroid imaging procedures was rather stable in the United States over theperiod 1978-1982. and the number of thyroid ultrasound procedures performed is so far relatively small
a n d does not appear to have significantly reduced thenumber of thyroid nuclear medicine procedures [M31].
Another area in which some replacement might be
expected is radionuclide liver scans, which could be
replaced by either hepatic ultrasound o r hepaticcomputerized tomography. No data are availzble on
the frequency of labelled monoclonal antibodies usedpredominantly for tumour detection.

D. ABSORBED DOSE
147. The range of administered activities for some
types of examinations in different countries is shownin Table 43. As with absorbed dose in diagnostic
radiology, the administered activity follows a skewed
distribution. There are some differences between
countries in the average activity used for certain
examinations. For example. in the United Statesadministered activity for a technetium-99m pertechnetate thyroid scan is about four times higher than inother developed countries. Kaul et ai. [K?] andJohansson et al. [J5] published data concerning thedosimetry of unsealed incorporated radionuclides anddiscussed the mathematical-physical and metabolic
dose models.
148. The effective dose equivalent in the USSR in
1980 from diagnostic radinnuclide examinations has
been reported by Knizhnikoi, et a!. [K13]. He has
indicated that the per capilt value is 0.04 mSv per
year. In the following years, in spite of the increasing
number of radionuclide examinations, the average
dose decreased to a per caput value of 0.03 mSv due
to expanded use of short-lived radionuclides [V7]. The
collective effective dose equivalent from all radionuclide
examinations was estimated t o be about 8,700 man Sv
for 1981 [V7]. Table 34 shows that the collective
effective dose equivalent for all diagnostic nuclear

medicine procedures in the United States in 1983 hasbeen estimated at 32,000 man Sv (0.14 mSv per c a p u t )[M30]. A more in-depth analysis of the effect of ageand sex-specific weighting factors has been performed
by Johansson 158, J9]. who concluded that detriment
was about 40% of that calculated from the effective
dose equivalent.
149. The annual per caput effective dose equivalent
for most developed countries ranges between 0.03 and0.14 mSv (Table 44). This is due mainly to the use ofiodine- 13 1 and technetium-99m. The percentagrs o lcollective effective dose equivalent attributable todifferent radionuclides are shown in Table 45. There
are large differences between countries.
150. Radiation dose estimates for orally administeredradionuclides used in upper gastro-intestinal diseaseh a t ~ ebeen calculated by Siegel et al. [Sl8]. Patient
exposure and radiation risk in Bulgarian diagnostic
nuclear medicine has been reported by Poppitz [P13].
One of the main sources of exposure in this particularcase was the iodine- 13 1 used in thyroid studies.
15 1 . As a result of the widespread use of radiopharmaceuticals labelled with iodine- 13 1 and technetium-99m there has been an increasing interest inassessing the radiation dose from breast milk following administration of such con~pounds to nursing
mothers. Many authors have discussed the subject[B 13, B 17, C4. 0 1. 0 2 . T6, V 1. iV241. The nature of
the radiopharmaceutical significantly affects breast
secretion, with technetium pertechnetate having as
much as 109'~of the activity in breast secretions [.All.
In almost all instances, the secretion rate in milk
24 hours after injection is insignificant. An important
exception to this arises in the case of iodine-125
fibrinogen. Ahlgren et al. [ A l l recommend that when
nursing mothers have received this radiopharmaceutical, breast feeding should be stopped for three
weeks.
152. The method of estimating average practlce incountries of various levels of health care can be used
to estimate the world-wide annual per caput doses andcollective dose from nuclear medicine. Repoited effective dose equivalents a n d genetically significant doses
for countries of health care level I are shoarn in Table 46
and are used as source terms. Since data are limited o rlacking altogether for countries of health care levels 11.
111 and IV, the values for those levels have been
estimated according to the frequent) of examinations.
This ma! result in a slight underestimate, however,
because it may be that longer-lived radionuclides arebeing uhed in less developed countries. For example.
technetium-99m has a short physical half-life, making
the dohe of the pharmaceutical lower than that of as~milar pharmaceutical labelled with iodine-131. At
the same time, the short half-life makes it impracticalto use technetium-99m in some less developed areas.
The annual per caput doses and collective effective
dose equivalent for health care levels I-IV are shownin Table 47. The annual collective effective dose
equivalent is estimated to be 74,000 man Sv; thegenetically significant collective dose is estimatedworld-wide to be approximately 15,000 man Sv.

E.

OCCUP.4TIONAL EXPOSURE FROMDIAGNOSTIC NUCLEAR MEDICINE

153. Over the past decade there has been rapid expansion in the use of nuclear medicine and particularly inthe use of the many technetium-99m labelled radiopharmaceuticals. Since these are administered predominantly by injection. there is a potential for
relatively high doses to rhc hands of the \vorkers.
Generally, Icad-shielded syringes are recomn~ended;ho\vever. they are nor always used. Direcr handling ofthin-walled plastic syringes can result in skin doses of
0.012-0.25 mSv per hour per MBq. Following injection, the patient represents another source of exposure
to the technolugist.
154. The limited data concerning occupational doses
incurred in the practice oi diagnostic nuclear medicinea r e presented in Table Jb. ,Mean annual individual
doses are 0.3-2.U mSv. Suclear medicine contributes
approximately 2% to the collective dose from all
occupational sources. The number of monitored workers in the field of nuclear medicine varies widelya m o n g countries. On the average, there are 100-300
examinations carried out annually for each monitored
worker in developed countries [U5, lV171. Certainly.
one nuclear medicine technologist can perform as
many as 1.000 in vivo studies annually; however, themonitored workers also include physicians. chemists,
physicists. pharmacists and, in some instances. clerks.

111.

THERAPEUTIC USES OF RADIATIONA.

FREQUENCY A N D T R E N D S

155. Data on the use of radiotherapy are often
confusing because of inlprecise definitions. With
teletherapy. a treatment course may extend over
several weeks and include many irradiations o r treatments. By contrast, brachytherapy and the use ofradiopharmaceuticals for therap) usually entail only
one o r two applications. For the purposes of thisAnnex. a teletherapy course o r a brachytherapy
application will be referred t o as a procedure. Someauthors refer only to the number of patients treated;
the use of their data may cause the frequency of radiotherapy t o be underestimated, since some patients are
re-treated for recurrent tumours. Additional confusion
arises in the matter of patient numbers, since somepatients may receive treatment for more than one
body area. Since the UNSCEAR 1982 Report [US],some data have become available on the number oftherapeutic radiology treatments in various countries.
Table 49 shows there was a slight annual increasein therapeutic radiology treatments in Canada from1978 to 1981. The annual frequency of treatments
is approx~mately 26 per 1,000 of population. The
estimated number of different types of cases treated byradiotherapy in some western hemisphere countries isshown in Table 50.
156. Hashizume et al. [H5, H6, H7] have reported
o n the status of external beam radiotherapy in Japan.

where 77.000 patients were treated in 1978 with
1.78 lob irradiations (treatlnents). The average numberof irradiations per treatment course was 21. with a naverage of 2.4 fields per patient. About 55% of thetreatments were done with cobalt-60 units. 38% withhigh-energy x rays, 6% with high-energy electrons a n d
1% ivith conventional x-ray units. More than 50% of
the patients were over the age of 45, about 4% were
under the age o f 14 years, and less than 1%)of patientswere treated for [ion-malignant disease. ~Marayuma
et al. [M 131 reported that in Japan in 1983 a total of
38,900 brachythcrapy procedures were performed.
36,300 (93%) of which were: in females.
157. In United States hospitals [ K 151 the number of
new patients per radiotherapy unit was about 300
annually from 1973 through 1979 and the number of
new patients per 1,000 population rose from 1.46 to
1.73 during the same period. Trends in equipment
have been discussed in both the UKSCEAR 1977
Report [UJ] a n d the UNSCEXR 1987 Report [U5].
Although orthovoltage uniu are still common in some
Latin American countries and in parts of Europe, hey
have been almost completely replaced in the UnitedStates by cobalt-60 units and high-energy accelerators.
Table 51 shows that in the United States from 1975 to
1980. there has been a n increasing use of high-energy
accelerators H hile the number of cobalt machines hasremained approximately stable.
158. By estimating average practice in countries atvarious levels of health care, i t is possible to obtain arough estimate of' radiation therapy acti\.ity world
wide. The known radiation therapy esperience by levelof health care is shown in Table 52. For mostcountries of health care level I, approximately 2,300
are perbrachytherapy and teletherapy
formed annually per million population. In mostcountries approximately 200 rich patients are treatedannuaily per machine. Using these source terms. it ispossible to estimate radiation therapy activity by levelof health care (Table 53). The estimated number ofprocedures and machines by level of health care iss h o w in Table 54. Bv this estimation method it
appears that there are approximately 5 million patientstreated by radiotherapy allnually and approximately
18.000 machines in use world-wide. The annual
genetically significant dose from radiation therapy incountries of health care level I is approximately
0.015 mSv (Table 55); estimates for countries of healthcare levels 11. I11 a r ~ dIV are also shown in the Table.
159. The future of radiotherapy is somewhat difficult
to predict. Certainly as the population ages, expands
and becomes more urban, both the need for a n d theavailability of radiation therapy will increase. In
addition, the spectrum of diseases will change withtime. One of the diseases in which there has alreadybeen such a change (and which often is treated withradiation therapy) is lung cancer. Since 1950. the lungcancer death rate has doubled, and in some instances
tripled, in many European countries [04].

160. At present, the Committee has no informationon the age distribution of the population receiving
radiotherapy in various countries nor does it have

information on the percentage of patients who may belong-term survivors. There are few new data since the
UNSCEAR 1982 Report on the uses of radiation
therapy for benign diseases. Probably the most common
use is administration of sodium iodide-131 for hyperthyroidism. The effective dose equivalent depends on
the percentage of iodine accumulated by the thyroid,
but in cases of hyperthyroidism the effective dose
equivalent usually exceeds 15 mSv per MBq [J4]. Wall
[W9] has indicated that in the United Kingdom in 1982.
treatments for thyrotoxicosis constituted 2.0% (7.600)
of all nuclear medicine procedures and had a mean
administered activity of 367 MBq and a range of 120 to
1.550 MBq. Similar experience has been reported from
Denmark in 1985 [E2]. Therapy with unsealed radionuclides represented 1.4% of all nuclear medicine
procedures. Therapy for thyrotoxicosis accounted for
88% of therapeutic procedures and thyroid cancer.
11%. The remaining 1% was for therapy with otherradionuclides (such as b9Sr for prostatic metastases
a n d I3'I metaiodobenzylguanidine, 32P andforother tumour types). The number of therapeutic
procedures for thyrotoxicosis in Denmark doubled
between 1977 and 1985 [E2]. Whether this is also
happening in other countries is unknown. In Sweden
between 1979 and 1982 about 3.300 therapeutic nuclear
medicine procedures were performed annually [M4,
M5, M6, M7]. This accounted for about 2.5% of all
nuclear medicine procedures. Due to the high absorbed
doses, particularly to the thyroid. where non-stochastic
effects predominate. therapeutic procedures are notusually included in assessment of annual collective
dose from nuclear medicine. Patients with either
thyrotoxicosis or thyroid carcinoma are predominantly
young and female and have long survivals comparedto other patients undergoing radiotherapy. Some
recent data from Sudan [S36] indicate that 10% of allradiotherapy treatments are for benign diseases, withthe majority of these (8.5% of the total) being forthyroid disease.
161. Extensive literature exists on endometrial
carcinomas occurring 10 o r more years after pelvic
irradiation for squamous cell carcinoma of the cervix
o r carcinoma of the ovary. and after radiationinduced menopause [CI3, F3, M5, R6. U4. US]. The
relative importance of such delayed effects depends
not only on the availability of radiotherapy in various
countries but also on the incidence of these tumours in
the various countries. Because the incidence rates ofcancers of various types vary from country to country.
the relative percentage of secondary tumour types andthe number of long-term survivors could also varyeven if radiotherapy were equally available.
162. As the prospects for long-~ermsurvival improve
following therapy and the possibility of secondary
radiogenic tumours increases, there has been renewedinterest in dose levels outside the useful radiotherapy
beam. This was briefly discussed in the UNSCEAR
1982 Report [U5]. In patients treated for Hodgkin's
disease, the relative risk of a second malignancy is
5.2 times that of the normal population. The mean
actuarial 15-year risk reported recently by Tucker [T9]
was 17.6%, of which 13.2% was due to solid tumours.
The risk of leukaemia, although elevated after radiation

therapy alone (relative risk I I compared to the normal
population), was much higher after either adjuvant
chemotherapy (relative risk 117) or chemotherapy
alone (relative risk 130). Such risks will continue t oconfound long-term follow-up studies to assess radiation risk in these patients.

B.

ABSORBED DOSE

163. The dose delivered outside the useful radiation
beam is determined mainly by scattered radiation in
the patient and to a lesser extent by radiation
scattered in air. For x-ray therapy units and linear
accelerators levels of leakage radiat~onthrough the
housing of the source contribute only 0. I-0.2% of thedose rate inside the useful beam. For neutron generators, however, the value may be 10 times as high [G6].
Results obtained by Kase et al. [KI] suggest that themachine collimators contribute 20-40Q of the dose t opatients outside the treatment field and that local
shielding of organs from scattered radiation generated
in the machine collimators could reduce the risk ofcarcinogenesis by as much as a factor of 2. Hudson
et al. [HI81 have also examined dose levels outside thebeam. with particular emphasis on the provision ofradiation therapy to a pregnant patient. They observedthat the shielding blocks themselves may contribute toscattered radiation and that this is most likely to occur
if the block is positioned immediately adjacent to themain beam. If the shielding block is moved away fromthe main beam, a dose reduction of some 30% is
possible. Williarns et al. [W14] and Petoussi et al.
[PI21 have published tables that include Monte Carlocalculations of dose to various organs for different
fields in radiotherapy. These results are extremely
useful since doses to organs and tissues outside theirradiated volumes are not often quoted in theliterature. Vasilev et al. [V4] have reported that when
patients are being treated for benign diseases, appropriate selection of x-ray potential can result in
improved precision of dose delivered as well as
reduction of dose to areas not being treated.
164. The annual genetically significant dose frombrachytherapy in Japan in 1983 is estimated to havebeen 13 mSv and the per caput mean bone marrow
dose, 0.31 mSv [M 131. The genetically significant dosefrom all radiotherapy in Japan in 1978 was 0.7 pSv andthe per caput bone marrow dose was 1.5 mSv. This
amounted to decreases of 93% and 26%, respectively.
compared to 197 1 [H6].
165. Of course. the fields o r body areas treated byradiotherapy vary widely from country to country. soa world-wide assessn~ent of risk from this practicewould require data not only on the number of patientsand treatments but also on the tissues o r fields
irradiated. As an example, cancer. of the lung andbreast are very common in the United States, although
overall, cancer is a less significant cause of death thanheart disease. In contrast, Olivares [ 0 3 ] pointed outthat cancer is the leading cause of death in Lima,
Peru, with stomach cancer being most common inmales a n d cancer of the cervix being most common infemales. While the Committee recognizes such major
regional differences. it feels that a complete discussionof them is beyond the scope of this Annex. For thisreason and others, discussed earlier. the Committee
has not attempted to calculate a n effective dose
equivalent from the practice of radiotherapy.
166. The optimization of radiotherapy is intimately
connected with the quality assurance and optimizationof cancer control programmes. Zaharia [Zl] has
indicated that in Latin America the most serious
obstacle t o cancer control is very late diagnosis andreferral for treatment. This is predominantly due tolack of awareness of the early signs and symptoms ofcancer. For example. in Peru. 92% of the patients
presenting for treatment of cancer were in stages I1
to IV. This is in contrast to Sweden. where more than
40% of the patients presenting were in stage I andmore than 80% were in stages I o r 11 [W20]. The
World Health Organization has examined most of the
aspects related to optimizing radiotherapy. I t indicatesthat the need for radiotherapy may not be uniform inall countries because the cancer sites in patientsreferred to radiotherapy institutes may have different
rates of occurrence. In most industrialized countries,
approximately one third of all cancer patients needradiotherapy either alone or combined with surgery.
Approximately one half need surgery either alone or
combined with other therapies. About one quarter ofall patients either d o not obtain, or are too advanced
for. specific therapy. In less developed countries. thedistribution of treatment needs will be different if
the distribution of cancer sites is different. For
example, when comparing North America with Latin
America, researchers have found that the death rates
from cancers of the breast (highest in North America),
cervix. uterus and larynx (higher in Central and SouthAmerica) often differ by a factor of 3 or more [P3].
167. The World Health Organization has also indicated that there is a difference in the age distributionof cancer patients from developed countries to developing countries, and the genetically significant dose
will vary accordingly. For example, the average age ofpatients diagnosed with cancer was 55.7 years for
Europeans. 45.9 years for Asians, and 35.9 years for
Africans. Of the age group 10-40 years, Africans
constituted 40%, Asians 31%, and Europeans only
12% [WZO].
168. The World Health Organization maintains aquality control and dose comparison programme forclinical dosimetry [W20]. In an IAEA/WHO doseintercomparison programme, radiotherapy institutes
received thermoiuminescent capsules by mail and wererequested to radiate them under varying circumstances.
Similar co-operative programmes exist in Ellrope and in
the United States. It is interesting t o note that, even inhighly industrialized countries, 15% of the institutions
made dosimetry errors of more than 10%. Such errors
may significantly affect the number of cases cured aswell as the complication rates of the radiation therapy.
Similar dosimetry intercomparison programmes havebeen reported on by Greene et al. [G7].

C. OCCUPATIONAL EXPOSURE
FROM RADIATION THERAPY
169. Occupational exposures during the practice ofradiotherapy come from several sources. In general.
with the use of external beam radiotherapy the rooms
are very well shielded and the attendant staff receive
little exposure. An exception to this is doses incurred
when using either neutron beams o r electron accelerators operating above 10 MeV. The neutrons cause theactivation of nearby materials, which then constitute asource of radioactivity and exposure to the staff evenafter the primary beam has been turned off. LaRiviere[Ll] and Hoffman [HI61 have examined this problem,
and it appears that 75% of the staff dose is due tophotoactivation products in the treatment head. The
remainder is due to other activation products in theroom: however, induced activity in the patient is not asignificant source. The exact occupational dose equivalent received by a worker in this manner is afunction of the workload. This is measured bypersonal dosimeters and appears to be 0.3-2.0 mSv.
annually. Tatcher et al. [TI] have examined patientstreated in a fast neutron therapy facility to determine
how much the (n, 2n) reaction and production ofcarbon-I l and oxygen- 15 in the patient added to thetechnologists' exposure. They concluded that patientswere the source of less than 10% of the occupational
exposure of the technologist.
170. A main source of occupational exposure fromradiotherapy is brachytherapy. This often involves theinsertion o r surgical implantation of radioactive wires.
needles or seeds. Pre-loaded surface applicators arealso sometimes used. There has been a trend towards
utilizing after-loading devices whenever possible t oreduce occupational exposure. This involves the prepositioning of an applicator or holder on o r in thepatient and then inserting the radioactive material a t alater time. The occupational dose received frombrachytherapy is also very dependent on whether thesource insertion is manual o r automated in somemanner. Once the sources have been inserted theradiation exposure of persons around the patient must
be considered. Since such exposure may be nonuniform. a comparison with doses incurred from othermore uniform sources may be difficult. Annual occupational absorbed doses from brachytherapy usually range
from 2 to 5 mSv [U4, U5].
171. Table 56 presents the limited data that areavailable concerning occupational doses from theentire practice of radiotherapy. Average annual individual exposures are 1-3 mSv. but, as pointed out.
they can be higher in those individuals intimately
involved with brachytherapy [H16]. The reported personal dosimeter values for radiation therapy workers
are undoubtedly closer approximations of the effective
dose equivalent than for diagnostic radiology workers.
This is because in radiation therapy the energy of theincident radiation is higher and because protective
aprons are not worn. The number of monitored
workers in radiotherapy is difficult to assess. At
present, data are available only from the UnitedStates, where it appears that there is one monitored
person for each 25-50 procedures annually.

1 . SUMMARY
172. The present state of knowledge regarding thefrequency of use of medical radiation and the associatedabsorbed dose is good for approximately 25% of theworld's pop~llation.Data are fragmentary for another
25% of the population, a r ~ dessentially no data exist
for 50% of the population. For this reason, theCommittee has de~eloped an estimation procedure
based on the good correlation that exists in mostcountries between population per physician and medical
uses of radiation.
173. The main sources of uncertainty in the effective
dose equivalent from medical diagnostic radiology are(a) the frequency of examinations and absorbed dose
per examination. especially in the case of fluoroscopy;and (b) poorly calibrated or malfunctioning equipment. The cffcctive dose equivalent from diagnostic
medical examinations is far greater than that fromdental or diagnostic nuclear medicine examinations.
174. The estimated world-wide per caput and collective effecti!re dose equivalent and genetically significznt
dose from medical radiation are shown in Table 57. I t
would appear that the per caput annual effective dose
equivalent is likely to be no lower than 0.4 mSv, but
may be as high as 1.0 mSv. Similarly, the annual
genetically significant dose ma) range from 0.1 to
0.3 mSv. The potential risk from medical radiation, if
calculated from the effective dose equivalent for
medical radiation. is probably an overestimate. This isparticularly true in countries where the older portionof the population receives most of the medical
irradiation.
175. The world-\vide collective effective dose equivalent from medical radiation is estimated to be
between 1.8 10' and 5 lo0 man Sv, and the geneticallysignificant collective dose to be between 0.5 106 and1.5 10"an
Sv. Between 90% and 95% of both thesevaiues are attributable to medical diagnostic radiology.
Dental radiography and nuclear medicine together
contribute only 510% of the collective dose. In
developed countries the contribution of diagnostic
medical radiation to the collective effective dose
equivalent is about 0.00 1 man Sv per examination.
176. There are many possibilities for dose reduction.
In developed countries it may be possible to reduce theper caput effective dose equivalent to half its present
value. In less developed countries the use of radiography rather than fluoroscopy, as well as thecalibration and maintenance of equipment, would
reduce the dose per examination. but the feasibility,
cost and magnitude of these measures are unknown.
One of the simplest and least expensive methods ofdose reduction is appropriate collimation of the beam
to conform only to the area of clinical interest. The
genetically significant dose can be substantially reduced
through the use of gonadal shielding, a practical, low-

cost method. In spite of such measures, the collective
effective dose equivalent may increase as x-ray examinations become more available in some countries. but
this increase may in fact be medically appropriate.
There have already been positive trends in dose
reduction (including decreasing absorbed dose per
examination as well as decreasing absorbed dose perpatient without jeopardizing the desired clinical objective). particularly in well developed countries.
177. Occupational exposure from medical practices
includes contributions from medical diagnostic radiology, dental radiography, nuclear medicine and radiation therapy. The sum of these for various countries isshown in Table 58. The average annual collective dose
equivalent from medical occupational exposure is about
I man Sv per million population. I n both Canada andthe United Kingdom, occupational exposure frommedical practice represents about 10%- of the collective dose equivalent from all occupational sources[U5]. In spite of the fact that the medical trses ofradiation are increasing in most countries, limited
trend data indicate that both annual individual doses
and collective occupational doses are decreasing by
10-20% per decade. In the United States. for example,
the number of occupationally exposed medical workers
rose as follows: 300,000 in 1960; 400,000 in 1970; and584.000 in 1980. During this time the annual collective
dose equivalent decreased from 580 to 410 man Sv(Table 58). For developed countries the averageoccupational exposure is about I pSv per examination.
The data also indicate that on average 150-750
examinations are carried out annually for each medical
radiation worker.
178, The frequency and total usage of medical
radiation is expected to increase over the next several
decades as a result of (a) a general aging of the world's
population; (b) an increase in the total number ofpeoplc; and (c) a trend toward urbanization in thedeveloping countries. By the year 2000, the collective
dose will probably increase by 50% and by the year
2025 it may more than double.
179. Consideration of the following points would
improve future assessments of exposures from the
medical uses of radiation:(a) collection of better data on the use of, andeffective dose equivalents from, both mass miniature radiography and fluoroscopy in developing
countries;(b) continuing analysis of the aging and urbanization of population groups and its effect upon useof medical radiation;(c) continued examination of the data for determining age- and sex-weighted dose equivalentvalues; and(dl collection of data on the number of patientstreated with radiotherapy and the proportion of
long-term survivors in various countries.

T a b l e

1

Annual f r p q u e n c y o f comnon d l d q n o s t l c x - r a y e x a r n l n a t l o n s p e r 1000 p o p u l a t t o n
Numbers I n p a r e n t h e s e s l n d l c a t e p e r c e n t

Exanlnation

Canada1980[cl1;hull and f a c e
Cervlcal rplne
0or:al r p l n r
1/ (111)
Uor:al lumbar S P .
Lurnbosacral ,pineCnes tRadlographlc
329.b (32.:)
Photofluorogr.
Fluoroscoptr
HdnnOgra$lhy
2 . 1 ( 0.3)
Abdomen
51 t r a c t andb a r l u n enemd
132.3 ( 1 3 . 0 )Chotecystographycrography
32.2(3.2)
hysterography
P e l v i s and h i p
Extremlttes
254.9 ( 2 5 . 1 )C o m u t e r tomograchy
Hedd
e.oay
Others151.3 ( 1 4 . 9 )l o t a l (medlcal)

i x d n i n a t ton

1016 ( 1 0 0 )

Japan
1986
I H ~ ~ I

Skcllandface
56.5(4.8)
Cervlcdlsplne
41.2(3.5)
0o::alsplrir10.8 ( 0 . 9 )9 o r s a l lumbar sp. 5 2 . 5 ( 4.5)
L ~ i m b o r a c r a l s p l n e 1 4 . 4 ( 1.2)
Chest
Radlographlc
445.0 ( 3 8 . 1 )Photofluorogr.
~luororcoplc
raLmogrdphy
I .( I)
Abdomen82.9 ( 7.1)
GI t r a c t andb a r l u n enemd
174.9 (14.9)
Cholecystography
1 0 . h ( 0.9)
Urography
13.0 ( 1.1)
Hysterogrdphy
1 0 1 )
Pelvlsandhtp
12.7(1.1)
lxtremitles
101.5 ( 8.7)
Computer tomography
tiead
God y
Otners
4 . 0 ( 1 )r o t a 1 (medical): I 7 2 ( 1 0 0 ) g/

Chlna
1980
[ZS]

f rance

1981-1982[ 8 9 . F1. N l ]0.4 ( 0 . 1
1 . 0 ( 0.3)
0.4 ( I)

Germany.
f e d e r a l Rep.
1918
[u5]

Italy

a/

1983
[PI]

8.9)
2.8)
2.2)
4.0)
1.l)

108.2 ( 1 2 . 4 )

3.5 ( 1 . 4 )

14.0
23.5
18.5
33.h
13.3

4.9

2 8 5 . 0 (34.1)

333.9 (39.6)

242.6 (32.6)
80.9 ( 1 0 . 8 )

4.8 ( 0.b)
2 9 . 6 ( 3.5)

21.9 ( 3.2)
4.1 ( 0.5)

6.1 ( 0 . 9 )22.; ( 3.0)

3 5 . 3 ( 4.2)
12.4 ( 1.6)
37.4(4.4)
3.4 ( 0.4)
62.2 ( 7.4)
182.6 ( 2 1 . 9 )67.8 ( 7.9)42.0(4.9)

46.3 ( 6 . 2 )12.6 ( 1.7)
12.6(1.7)

49.0 ( 5.2)
112.9 ( 2 0 . 2 )40.1 ( 5 . 4 )138.8 ( 1 8 . 6 )( 1.9)

1 8 8 . 1 (72.6)-

0.4 ( 0.1)
9 . 2 ( 3.6)
0.2 ( 0.1)
O.l(O.1)
1.5 ( 0.6)
5.9 ( 2.3)

(
(
(
(
(

35.7 ( 4.1)
21.3 ( 2.5)

19.4 ( 2.3)

259 ( 1 0 0 )

835 (ILIU)

Netherlands
1980
I86 I

Norway1980- 1983
153.54142.9(6.6)

b.3(1.0)c/36.4 ( 4 . 9 )--43.4 ( 1 6 . 1 )41.5 ( 5.6)
26.7 ( 3 . 6 )12.6 ( 1 . 1 )--

5.2 ( 0 . 7 )
5.2 ( 0.7)
14.1 ( 1 . 9 )863 ( 1 0 0 )

c/

744 ( 1 0 0 )Spa i n1986
[V~I

Sweden1979
IU~I

15(3.1)43.3(8.R)

9 1 (19.8)

9.6 ( 1.9)
11.8 ( 3 . 6 )
2.6 ( 0 . 5 )135.0 ( 2 0 . 8 )123.3 (19.2)(19.0)
84.4 ( 1 3 . 2 )10.9 ( 1.7)
5.2 ( 0.8)
8.4 ( I .
2.5 ( 0.4)
12.7 ( 2.0)
8 . 0 ( 1.2)

128 (2b.0)

176.8 ( 3 5 . 8 )

I 4 ( 2.9)45 ( 9.2)

6.4 ( 1 . 3 )11.7 ( 2.4)

19.1 ( 3.0)
1
( I
15.6 ( 2.4)
O.g(O.1)
33.6(5.2)
113.3 (26.7)

3 3 : l ( 5.2)
3.0 ( 0.1)
20.7 ( 3.2)

40 j 8.2)

46.4(7.2)
146.3 (22.8)

IS(3.1)25 ( 5.1)

32.6 ( 6.6)
11.8 ( 2 . 4 )22.8 ( 4.6)
0 . 6 ( 0.1)
36.40.4)
112.0 (22.1)

7 ( 1.4)18

1.4 ( 1 . 2 )
2.8 ( 0 . 4 )115(17.9)

91 (18.6)

641 ( 1 0 0 )

490 (lOO)c/

9 . b ( 1.5)

3 0 . 8 ( 4.8)

10.0 ( 1 . 6 )
0.6 ( 0.1)
21.0 ( 4.2)

)
)

)
)

I

(

2.8)

648 ( 1 0 0 )-

13 ( 2 . 6 )

1.2 ( 0.2)
0 . 7 ( 0.1)
8.0 ( 1.6)

494 ( 1 0 0 )r/

T a b l e 1. c o n t l n u e d~pRusslanFederation
1980

fxamlnatlon

S k u l l and f a c e
52.2
Cervlcal splne
11.5
Dorsal splne
6.9
D o r s a l lumbar sp. 17.4
Lumbosacral s p l n e
4.6
Chest
Radtographtc
118.0
P h o t o f l u o r o g r . 525.0
fluoroscopic
149.0
Mamnography
Abdomen
GI t r a c t andb a r l u m enema
181.0
Cholecystography
9.7
Urography
42.0
Hysterography
P e l v l s and h l p
10.0
txtremitles
123.2
Computer tomography
Head
Body
Others58.0

UnltedKlngdom &/
1983
[Hal

UnltedStates1981
1~281

Level I
countrles

39 ( 7.8)
13 ( 2.7)
6 ( 1.2)

36.1 ( 4.6)
22.4 ( 2.8)
7.9 ( 1.0)

24 ( 4.5)

56.8 ( 7.2)

50 (
20 (
13 (
25 (
25 (

163 (32.9)

282.0 ( 3 5 . 7 )S(0.9)
21 ( 4.2)

5.7(0.7)
34.8 ( 4.4)

20 ( 4.0)
6 ( 1.3)
8 ( 1.7)
122 ( 4.3)
67 (13.1)

55.1 ( 7.0)
15.0 ( 1.9)
18.5 ( 2.3)

4.0)
0.9)
0.5)
1.3)
( 0.4)((((( 9.0)(40.1)(11.4)(13.8)( 0.1)( 3.2)el(average)

b/

E/

d/

el

1
89 (20.3)

11.8 ( 1.5)
2 . 6 ( 0.3)
22.5 ( 2.8)

7 ( 1)
2 ( 1)
32 ( 4)488 ( 100)190 ( 100)

( 9.4)

4 ( 0.8)( 4.4)

Northeast I t a l y only.
Includes p e l v l s .
Does n o t I n c l u d e mass s c r e e n l n g .
Great B r l t a i n o n l y .
Excluding Chlna.
T a b l e

2

D l a q n o s t l c x - r a y e x a m l n a t l o n s I n t h e USSR
IV7l

Numberp e r 1000 p o p u l a t l o n
fxamlnatlon

Change- 50%

Fluoroscopy
Radiography
Photofluorography

439
111
183

220
235
503

+37%
+175%

Total

793

958

+2I%

T a b l e

3

O l a q n o s t l c x - r a y machlnes I n some w e s t e r n hemisphere c o u n t r l e s

1973 [ P l b ]1980 [ I 7 1

Country
Populatlon(thousands)

Unlts per1000
population

24290
10309
1896
6726
54300
209851

0.21
0.07
0.16
0.04
0.06
0.56

Unlts

Argent l n a
5170
Chlle
720
Costa R l c a a/ 300
Ecuador300
Mexlco3500
U n l t e d S t a t e s 117151

a_/

'

3)

240 ( 3 0 )
25 ( 3 )
2 ( 1)
7 ( 1)
55 ( 7)~a/3)

20.7 ( 7.6)
198.2 ( 2 5 . 1 )( 0.8)

1308 ( 1 0 0 )

2)
2)

70 ( 9 )
13 ( 2)24 ( 3 )
2 ( 1)
38 ( 5 )
150 ( 1 9 )-T o t a l (medical)

6)(thousands)

U n l t s per
1000
populatlon

27862
11104
2245
8354
71910
2211 58

0.36
0.12
0.06
0.04
0.05
0.60

Population

Unlts

10000
1320
124
345
3800
137000

Number o t u n l t s r e p o r t e d I n 1973 may l n c l u d e d e n t a l x - r a y u n l t s .

T a h l e

4Olagnostlc x-ray examlnatlons by level of health care

Level
of
healthcare

I

Country

Annualexamlnatlons
per 1000
populatton

Argent lna
Canadaf Inlandf rance
Germany. Fed. Rep.
Italy
Japan
Llbyan Arah Jamal.
Netherlands
NorwaySpa l nSwedenUn l ted K l ngdom
Unlted States
USSR

1016
958
835
863
744
1380

Chjle
Chlna
Colombla
Costa Rlca
Cuba
Oomlnlcan Republ lc
Equador
Islamlc Rep.of IrannexlcoNlcaraguaParaguay
Peru
TurkeyUruguay
Venezuela

111

IV

Populatlon
per x-raymachlne

2800
3200
2700
3290
8000

648
64 1
490
494
488
790
958

4400
5000
1800

Year

Reference

1978-1982
1980
1984
1981-1982
1978
1983
1986
1977
1980
1983
1986
1979
1983
1980
1981

[I71

1977
1977
1977
1977

[ c7 I[ell[ T3 1[89,nl,~ll][ u5 1

[ell]
[nla]
[C71
1861
153. 541
IV41[us][Wb, Cll]
Ln281
[v,]

166
259
21 1
270
139
20
36
180
70
57
80

Kenya
Indla
Llberla. Slngapore
Srl Lanka
Sudan
Thal land
Ethlopla
Ghana
Cdte d'lvolre
tilqerla

2240
2530000010000019000090000

T a b l e

5

Averaqe dlaqnostlc x-ray examlnatlons
b v level of health care

Level
of

healthcare

Annua 1
examlnatlonr
per 1000
populatlon

Population

per x-raymachlne[C71[c71[ C ~ I

T a b l e

6fstlmated world-wlde dtaqnostlc x-ray examlnatlons and machlnes ln 1981
Numbers In parenthese; lndlcate per cent ol total

Lcvrl
of
healthcare

Dlngnortlc
examlnal\or!r

Approxlmdte
rxnmInat Ions

(mllllons)

Olagnostlc
x-ray
machines(thousands)(mIlllon5)

mdchlneIV

1300 (26)1150 (35)lZ70 (24)
7 3 0 (15)330 (76)
8 8 (20)
1; ( 3)4 ( 1)

1000 ( IS)
160 (19)61 ( 4 )
22 ( 21

3000
3000
4000
5 500

total

SOOO(100)

44@(100)

1380 (100)

I
II
I I1

Populat ton

T a b l epr r7Olaqnostlc x-ray eramlnatlons In some Lattn Amerlcan counlrles In 1981
(per cent)f 171

Country

Nervoussy5tema/Ch\lc
Costa Rlca
Domlniran Republlc
icuadorE l Salvddor
M~xlcoS t . Lucla

a/

5
6
10
3
10

Chest

Neck

40

2

22
33
26

1
2
4
3
b

38
40

Olgestlve
Urotract
genltal

C

50

.
I

18
9
19
8
6
12
1

IxtremItles

5
8
5
5
6

30
36
30
35
26
28
72

5
5

A11 countries are of sedlth care level I 1

r a bi eM
Olaqnostlc x-ray exa~iFttlons by level o f h ~ a l t h care(per cent)Level o f health care---

Examlnd!lon

Head and neck
Chest
Abdomen and d lgest lve
tract and gallbladder
Urogenltal
txtremltles
Other
Sample slre(number of countrles)

33

9
36

8
50

18

13

h

4

6

19

4
73

18

21
9

(12)

(7)

8

a/

3'

(2)

10)

a/ Informatton for health care level IV not avalldble.

Other

IH
I

1Y
II
9
II

T a b l e

9Estlrnated percent of urban and rural populations
recelvlng dlaqnostlc x-ray examlnatlons
In some Latln Amerlcan countrles In 1981
1171
Country

Urban

Rural

Chlle
Costa Rlca
Oomlnlcan Republlc
El Salvador
HexicoSt. Lucla

15
5
15
9
20
6

2
2
10

T a b l e

1023Annual frequency of dlaqnostlc x-ray examlnatlons
per 1000 populat lon a_/

Country

1955-59

1964

1964-70

1974-76

1977-79

1980-83

Reference

CanadaChlna &/
FranceGermany, Fed.Rep.
Japan
Netherlands
NorwaySwedenTurkeyUnlted Klngdom
USSR
USSR e/Unlted Statesa/ Includes m s s screenlng and fluororcopy unless othervlse Indicated.

&/ Refers t o Shangdong Provlnce; frequency for 8elJlng (1983): 671 [Zll].

c/ Does not lnclude mass screenlng.
&/ Does not lnclude fluoroscopy.

e/ Russlan Federatlon.

T a b l e

11

Dental radlography. 1975-1987[BE. 811, C11, H20, UlO. Ul4. Pll. U4. US. W6]

Level
of
healthcareIF l lms per

Country

1000
populatlon

Procedures
per 1000
population

Populat lon
permachlnea_/Argentlna
FranceItaly
Japan
PolandSwedenUnlted Klngdom
Unlted States
Rounded average

I1 b/

Chile
Costa Rlca
EcuadorHexlco111

Srl Lanka

250

2500

0.8

a/ Oata provlded are dlfflcult t o evaluate for number of dentalb/m c h l n e s since standard radlographlc machlnes a r e often used.
Oata for health care level I1 countrles from 1171.

T a b l e

12Cstlmated mrld-ulde dental radloqra~hv. 1980

Level
of
healthcare

fllms per1000
populatlon

Procedures
per 1000
populatlon

Estimated
total
procedures(mllllons)

Populatlon
permachlne

340

Total

(440)

a/ Numbers In parentheses refer to estlmates for levels 1 1 - I V
based on dlagnortlc radlologlc actlvtty.
may be hlgh by an order of magnltude.

T a b l e

These estlmates

13

Age and sex dlstrlbutlon of Claqnostlc x-ray examlnatlons(per cent)NorwayExamlnatlon

Age and sex
1983[53. 541

Skull and face

UnltedKlngdom
1983
I Wb I

UnltedStates1980[UlOI

UnttedKlngdom1983[wbl

UnltedStates
1980
[Ulol

3.7
2.4
6.1
6.9
7.0
13.9
8.5
8.1
16.6
16.4
13.4
29.8
16.4
16.5
32.9
52.6
47.4
100.0

4. 6
3.4
8.0
7.4
7.5
14.9
6.7
8.1
14.8
14.6
14.4
29.0
15.6
17.7
33.3
49.9
51.1
100.0

< 15 male

femaleboth
15-29 male
femaleboth
30-44 male
femaleboth
45-64 male
femaleboth> 64 male
femaleboth
All ages male
femaleboth

Chlna
Examlnat lon

Chest

Age and sex< I5 male
femaleboth
15-29 male
femaleboth
30-44 male
femaleboth
45-64 male
femaleboth> 64 male
femaleboth
All ages male
femaleboth

NorwayPoland1980[24. 251

1983[S3. 541

1978
[NS]

10.4
6.5
16.9
14.1
13.3
27.4
12.4
12.4
24.8
14.1
9.9
24 .O
4.0
2.9
6.9
55.0
45.0
100.0

5.8
4.0
9.8
4.7
4.3
9.0
7.1
7.5
14.6
18.7
17.1
35.8
15.9
14.9
30.8
52.2
47.8
100.0

7.3
6.0
13.3
9.2
7.7
16.9
9.6
9.1
18.7

&I

26.0
25.1
51.1
52.1
47.9
100.0

a/ Chest fluoroscopy, whlch constitutes 95% of all chest examtnatlons ln Chtna.

Table 13, contlnued

Examlnat ton

NorwayPoland1983
IS3. 541

1978
[N51

Chlna

NorwayPoland

(24.

1980
251

1983
(53. S4]

1978
[N5]

2.1
0.9
3.0
13.7
9.2
22.9
15.8
9.9
25.7
21.7
15.8
37.5
6.7
4.2
10.9
60.0
40.0
100.0

3.2
2.4
5.6
8.4
5.4
13.8
10.2
8.6
18.8
18.8
16.2
35.0
12.2
14.4
26.6
52.8
47.2
100.0

0.9
0.7
1.6
9.8
7.5
17.3
14.0
12.4
26.4

54.0
46.0
100.0

NorwayPoland1983[53. 541

1978
[NSI

0.2
0.2
0.4
5.0
6.6
11.6
8.2
13.2
21 - 4
15.2
23.6
38.8
10.7
17.1
27.8
39.3
60.7
100.0

4.5
5.9
10.4
4.0
6.4
10.4
9.5
7.3
16.8

Age and sex

UnltedKlngdom
1983
IWbI

UnltedStater1980
lUl 01

UnltedKlngdom1983[u61

UnltedStates
1980
[UIOJ

0.9
0.4
1.3
6.6
4.9
11.5
13.4
12.5
25.9
18.2
15.0
23.2
9.8
18.3
28.1
48.9
51.1
100.0

1.4
1.5
2.9
6.0
9.2
15.2
8.4
11.9
20.3
14.3
18.7
33.0
11.3
17.2
28.6
41.5
58.5
100.0

UnltedKlngdom1983[wbl

UnltedStates
1980
[Ulo]

0.4
tO.1
0.4
3.5
5.8
9.3
4.9
11.3
16.2
14.8
17.7
32.0
15.2
26.9
32.1
38.8
61 - 2
100.0

1.1
1.1
2.2
3.5
6.9
10.4
5.5
10.8
16.3
13.6
21.2
34.0
14.1
22.2
36.3
37.8
62.2
100.0

< 15 male

Abdomenf ema 1 eboth
15-29 malefema 1eboth30-44 male
femaleboth
45-64 male
femaleboth> 64 malefe.mleboth
All ages male
femaleboth

Examlnation

Age and sex

Upper GI(barlum meal)< 15 male

femaleboth
15-29 male
femaleboth
30-44 male
Femaleboth
45-64 male
femaleboth> 64 male
femaleboth
A l l ages male
femaleboth

Examlnatlon

29.3
25.4
54.7

Age and sex--

Barium enem

< IS male
femaleboth
15-29 male
femaleboth
30-44 male
femaleboth
45-64 male
femaleboth> 64 male
femaleboth
All ages male
female
both

28.3
34.1
62.4
46.3
53.7
100.0

Table 13, c o n t l n u e d--

NorwayUnltedKlngdom
1983
IWbI

UnltedStates1980
IUlOl< 15 male

< 0.1

< 0.1

femaleboth
15-29 m a l efemaleboth
30-44 m a l efemaleboth
45-64 male
femaleboth> 64 m a l efemaleboth
A l l ages m a l efemale
both

0.2
0.2
2.8
7.0
9.8
7.2
05.9
23.1
13.8
27.0
40.8
8.3
17.8
26.1
32.1
67.9
100.0

1.1
1.1
1.5
9.1
10.6
8.2
10.0
18.2
11.8
33.2
45.0
8.5
12.6
21.1
30.0
70.0
100.0

0.3
0. 6
0.9
4.5
12. I
16.6
8.1
15.9
24.0
14.0
20.1
34.2
9. 6
14.7
24.3
36.6
63.4
100.0

UnltedKlngdom
1983[Wbl

UnltedStates
1980
[ulol

6. 5
3.9
10.4
8.1
8.5
16.6
9.9
5.3
15.2
24.2
7.7
31.9
19.1
6.8
25.9
67.8
32.2
100.0

1.8
2.7
4.5
7.1
9.7
16.8
9.0
11.6
20.6
15.6
15.5
31.1
15.0
12.0
27.0
48.5
51.5
100.0

UnltedKlngdom1983
1Wb 1

UnltedStates1980[UIo]Examlnatlon

Age and sex

Blllary tract

Examlnat t o n

Urogramc 15 m a l efemaleboth
15-29 male
femaleboth
30-44 m a l efemaleboth
45-64 male
femaleboth> 64 m a l efemaleboth
A l l ages m a l efemaleboth

Examlnat l o n

Lumboracra 1
splne

NorwayPoland1983
153. 541

1978
IN51

4.4
9.9
14.3
5.4
7.5
12.9
8.0
9.3
11.3
16.6
13.5
29.1
17.4
7.8
25.2
52.0
48.0
100.0

6.6
10.4
17.0
7.9
9.9
17.0
11.0
10.5
21.5

51.3
48.7
100.0

NorwayPoland1983
153. 541

1978
IN51

Age and sex

25.8
17.9
43.7

Age and sex< 15 m a l efemaleboth
15-29 m a l efemaleboth
30-44 m a l efemaleboth
45-64 m a l efemaleboth> 64 male
femaleboth
A l l ages m a l efemalebothTable 13, contlnued

Examlnatlon

Pelvls and hlp

NorwayPolandUnltedKlngdom
1983[Wb]

UnltedStates
1980
[Ulol

1983
[53. 541

1978
[N51

NorvayPoland1978[N5]

UnltedKlngdom
1983[Ha]

UnltedStates
1980
[ulo]

1983
[S3. 541

5.5
4.2
9.7
12.1
9.8
21.9
8.1
9.1
11.2
12.1
14.1
26.2
10.5
14.5
25.0

48.8
51.2
100.0

6.7
4.6
11.3
10.7
8.3
19.0
9.9
8.5
18.4
13.9
13.2
27.1
7.6
15.6
23.2
48.3
51 .7
100.0

Age and sex< 15 male
femaleboth
15-29 male
Femaleboth
30-44 male
femaleboth
45-64 male
femaleboth> 64 male
Femaleboth
All ages male
femaleboth

ixamlnatlon

All dlagnostlc
examlnatlons

Age and sex< 15 male
Femaleboth
15-29 male
femaleboth
30-44 male
Femaleboth
45-64 male
Femaleboth> 64 male
femaleboth
All ages male
femaleboth

Is1.Rep.
of Irzn
1980
[S19j
9.0
6.7
15.7
?I .6
10.7
32.3
16.0
11.0
27 .O
12.4
7.5
19.9

-

3.2

1.4
4.6
63.0
37.0
100.0

50.9
49.1
100.0

T a b l e

14

Cardlac lmaqlnq procedures ln the Unlted States(thousands)[Nl I

Examlnatlon
Anglography
Coronary and left
ventrlculography
Echocardlography
Radlonucllde
blood pool
Radlonucllde
lnfarct scan
Radlonucllde scan
perfuslon/lschemla
thalllum

1972

1973
200
200

0
11

2
0

25

T a b l e

15

Head x - r a y and r a d l o n u c l l d e e x a m t n a t l o n s I n t h e U n l t e d S t a t e s(thousands)
IE61

Examlnat \ o nHead CT
Sku1 1
Pneumoencephalogram
Arterlogram
Radlonuclldeb r a l n scan
Radlonuclldec l sternogram

1964

1970

2500

3600

1972

0

1973

1978

(10

1980

1600
3 700

48

2
31 5

121
1250

1546

12

T a b l e

867
16

16

namoaraphy examlnatlons I n t h e U n l t e d S t a t e s(thousands)
IN11

Number I n hospitals
Number I n s u r g e r i e s

53
13

199
47

1000
260

Total

66

246

1260

Per 1000 f e m a l e
populatlon

0.6

T a b l e

2.4

11

17

S k l n dose I n t h e p r l m a r y beam p e r f l l m a_/(mSv)

Examlnatlon(proJectlon)b/Canada

Italy

Poland[ c2 1[I11[Jl]

UnltedK lngdom[H2.S16]

UnltedStates[u9)

S k u l l (LAT)
Chest (P/A)
Radlographlc
Photofluorographlc
Abdomen (A/P)
Retrograde
pyelogram (A/P)
C e r v l c a l s p l n e (A/P)
Thorac l c s p l n e (A/P)
Lumbar s p l n e
(Alp)

a/
b/

Values e x p r e s s e d as medlan. numbers I n p a r e n t h e s e s r e f e r t o r a n g e whenavallable.
A/P and P/A and LAT r e f e r t o beam e n t r a n c e and e x l t on t h e body.
For
example, on a P/A c h e s t r a d l o g r a p h t h e beam l s l n c l d e n t upon t h e p o s t e r l o r
t h o r a x and e x l t s o n t h e a n t e r i o r t h o r a x .

T a b l e

18

Mean number o f r a d l o q r a ~ h sand f l u o r o s c o p v s c r e e n l n g t l m e
b y e x a m l n a t l o n l n France. 1982
[Ml I

Mean numberof fllms

Examlnatlon

Fluoroscopy
screenlngt \me( 5 ) a/Examlnatlons
lnvolvlng
fluoroscopy(XI

Cervlcal splne
Thoraclc s p l n e
Lumbar s p l n e
Sacro-lumbar s p l n e
Pelvls, h l p
AbdomenI V urography
Hysterography
Cholecystography
Skull
Barlum enema
8 a r l u m meal
Thorax
Cerebral anglography
Thoraclc a n g l o g r a p h y
Abdomlnal a n g l o g r a p h y
I n f e r l o r llmbs anglography
Phlebography
O b r t e t r l c a l abdomen
Pyelography
a_/ f o r s t a t l c e x a m l n a t l o n s . such as lumbar s p l n e .
c e r v l c a l splne.
abdomen e t c . . f l u o r o s c o p y 1s m o s t l y used f o r c e n t r l n g t h e p a t l e n t .

T a b l e

19

R a d l a t l o n doses t o neonates r e c e l v l n q d l a q n o s t l c e x a m t n a t l o n s
I n t h e U n l t e d Klnqdom( s a m p l e s l r e 85 I n f a n t s )[ RS I

Gestatlon(weeks)Meanblrthwelght(kg)

Meannumber o f
fllms
per lnfant

Meannumber o f
C T scansper l n f a n t

Meanmarrow
dose(mSv)

T a b l e

20

Orqan doses f r o m c a m u t e r i z e d tomoqraphy scans I n Japan[NlOI

Mean absorbed dose (mSv)
Organ

Ovary
TestesBone marrow
Bra lnSubllngual gland
Thyrold
BreastStomachLung
L lv e r
Upper l a r g e i n t e s t i n e
Lower l a r g e l n t e s t l n e
Rec t urn
Eye ( r l g h t )CranlalUpperabdomlnal

Lower
abdornlnal0.0043
0.004
1.41
25.0
1.45
9.60
0.15
0.04
0.18
0.04
0.006
0.006
0.005
28.0

0.18
0.11
1.74
0.06
0.45
0.54
14.8
7.60
6.80
5.80
0.26
0.26
0.16
0.15

9.50
0.175
2.60
0.06
0.04
0.043
0.21
0.43
1.13
0.38
12.0
12.0
9.20
0.03

T a b l e

21

Orqan doses f r o m d e n t a l radiography I n t h e U n l t e d Klngdom

IW3 I

Mean dose e q u l v a l e n t
per e x a m l n a t l o n (mSv)
Organ

GonadsBreastBone marrow
Lungs
Thyrold
Bone s u r f a c e
Braln
Sal l v a r y g l a n d s
Slnuses

Intraoral(2 fllms)

Extraoral( 2 fllrns)
0.001
0.005
0.02
0.001
0.01
0.10
0.03
0.10
0.05

Pantomo9raPhy( 1 fllrn)(0.005
0.01
0.05
0.01
0.01
0.20
0.50
1.1
0.20

T a b l e

27Collectlve effectlve dose eaulvalent from d l a ~ n o s t l c x-ray eramlnatlons
In France. 1987
[nzl

Collective
Examlnatlon

Cervlcal splne
Thoracic splne
Lumbar splne
Sacro-lumbar sptne
Pelvls. hlp
AbdomenI V urography
Hysterography
Cholecystography
Skull
Barlum enema
Barlum meal
Thorax
Cerebral anglography
Thoraclc anglography
Abdomlnal anglography
Inferlor llmbs anglography
Phlebography
Obstetrical abdomen
Pyelography-a/effectlve
dose
equlvalent(man Sv)

Accounted
for byfluoroscopy
(X)

1680
2100
8580
3400
5350
4120
20580
81 0
4860
4990
8210
7460
4110
1780
680
5590
280
940
930
370

1 8 a/
16.5 a/1 3 a/
7 a/
3 a/
6.5 a/
11.5 a/17
34.5
1 0 a/
21 - 531 - 5
3 a/
15
70.5
34
15
37
8 a_/
24

Examlnatlons In uhlch fluoroscopy 1s only used
for posltlonlng the patlent prlor t o fllm
radtography.

T a b l e

23

Procedures t o reduce c o l l e c t l v e dose e g u l v a l e n t
I n d l a g n o s t l c x-ray e x a m l n a t l o n s

E n t r a n c e dose
reductlon
ReferencefactorArea

ProcedureA l l types

Ellmlnatlon o f medlcallyunnecessary procedures
Introductlon of quallty
assurance programne ( g e n e r a l )Decrease I n r e j e c t e d f l l m s
t h r o u g h QA programne
I n c r e a s e o f peak k l l o v o l t a g e
Beam c o l l l m a t l o n
Use o f r a r e e a r t h screens

Radlography

Pelvlmetry
Fluoroscopy

O l g l t a l radlography
Computed ton~ography(head)
namnography

a/

1.2

[C9]

2.0

[CS]

1.1

[ G l , PI51

1.5
1.0-3.0
2-4

Increase o f f l l t r a t l o n
Rare e a r t h f l l t r a t l o n
Change From p h o t o f l u o r o g r a p h yt o chest radlography
Use o f c a r b o n f l b r e materials
Replacement o f CaUO4 screensw l t h spot f l l m technlque
E n t r a n c e exposure g u l d e l l n e s
Gonadal s h l e l d l n g
Use o f CT t o p o g r a n
Acoustlt slgnal relatedt o dose r a t e
Use o f 105 inn camera
R a d l o l o g l s t technique
Variable aperature l r l s
on TV camera
Change f r o m c h e s t f l u o r o s c o p yt o radlography
H l g h and l o w dose s u l t c h l n g
Decrease l n c o n t r a s t resolution
Use o f p u l s e d system
Gantry angulatlon t o exclude
eye f r o m p r l m a r y beam
I n t e n s l f y l n g screensO p t l m l compresslon
Flltratlon

1.7
2-4
4-10

[W13]
[ J 7 , U35]
[K21.N7.
S8, HZ][K21 .M34.W13][TlOJ[ J l , n38. N6]

2
4

[HI71
[K21 1

1.5
2-10
5-10
1.3

[LZ]

b/ [ P I 4 1
[S27]
[A41

4-5
2-10
3

[R9]
[R9]
[L31

20
1.5
2-3
2

[s32]
[L3]
[R4]
[ R4 1

2-4 c/
2-5
1.3-1.5
3[IS][N3. 5171
[N3]
[HI 1

a/ The r o l e o f p r o p e r t r a l n l n g I n r a d l a t l o n p r o t e c t l o n I s e x t r e m e l y I m p o r t a n t .
Oose r e d u c t l o n f a c t o r s
d l f f l c u l t t o quantify.
b/ To gonads.
C/ T O eye.

I n thlsr e g a r d may

T a b l ebelarge,

howeverthey

24

G e n e t l c a l l y s l q n l f l c a n t dose i n France I n 1982
(QSV)

Fluoroscopy

Radlography

Total

Age
(years)
Males

Total

Females

Hales

Females

Males

Females

Total

are

T a b l e

25

AveraQe dose e a u l v a l e n t I n t h e female gonads p e r e x a m l n a t l o n(mSv)

FranceExamlnatlon

n2 I

Germany
fed.Rep.
[HI51

Great
Brltalnin41

1sl.Rep.
of Iran
is191

(P11

Japan

PolandTurkey

USSR

[H41

[Jll

Swltzerl a n d a/
[PI41

[Yll

[V71

a/

Italy

Cervical spine
Oorsal s p l n e
Oorsolumbar s p l n e
Lumbosacral s p i n e
Pelvls, h l p
Abdomen. w i t h o u t
preparatlon
I V urography
Hysterography
Cholecystography
Skull
Earlurn enema
GI tract
ThoraxExamlnatlon

Cervlcal splne
Dorsal splne
Oorsolumbar s p l n e
Lumbosacral s p l n e
Pelvls. h l p
Abdomen, w l t h o u t
preparatlon
I V urography
Hysterography
Cholecystography
Skull
Barlum enema
GI t r a c t
Thorax

a/
b/

C/

i/

Per f l l m .
H l p and upper femur.
Pelvjs.
Includes fluoroscopy.

UnltedStatesIRE1

T a b l e

26

Average dose e a u l v a l e n t I n t h e male aonads p e r e x a m l n a t l o n(msv)

France31

Examlnatlon

Cervlcal splne
Dorsal splne
Oorsolumbar s p l n e
Lumbosacral s p i n e
Pelvls, h l p
Abdomen, w i t h o u t
preparatlon
1V u r o g r a p h yHysterography
Cholecystography
Sku1 1
Barlum enema
GI t r a c t
Thorax

0.02
0.15
0.60
0.86
1.48

Germany
Fed-Rep.
[HI51

d/

[Pll

0.05
0.1 b/
2.5

8.4

b/

1.28
1.02

0.06

Turkey

USSR

[YIl

[V71

0.93
0.02
3.70
0.95
0.04

Japan

Poland[ H4 I[Jll

Abdomen. w l t h o u t
preparatlon
I V urography
Hysterography
Cholecystography
Skul 1
Barlum enema
GI t r a c t
Thorax

C/

Italy

0.61
2.46

Cervlcal splne
Dorsal splne
Oorsolumbar s p l n e
Lumbosacral s p l n e
Pelvls, h l p

a/1sl.Rep.
of IranIS191
0.01

Examlnat l o n

b/

Great
Brltaln[W41

Per f l l m .
H l p and upper Femur.
Pelvls.
Includes fluoroscopy

Swltzerl a n d a/
[Pl41

UnltedStates[Re1

T a b l e

27Contrlbutlon to the annual fJenetlcal1~slqnlflcant dosefrom dlaqnostlc x-ray examlnatlons(per cent)France1sl.Rep.

Italy

Japan

1983
[PI]

1979
IHIII

o f Iran

Examlnatlon
1982[n1.n21

1980
[sisi

Skull
Cervlcal splne
Dorsal splne
Dorsal lumbar splne
Lurnbosacral splne
Pelvls and hlp
Abdomen
UrogramHysterography
Cholecystography
Upper GI (barlum)
Barlum enema
Chest
Other

0.5
0.5
2.5
5.0
2.4
28.5
6.2
29.8
0.7
1.8
5.4
6.4
1 .B
8.5

0.2
-

Annual genetlcallyslgnlflcant dose(mSv) a/0.30

TurkeyUnltedStates1977
1980[ Y I I [Nil

0.01
0.02

)
) 25.7

26.7
6.3
10.4
2.6
1.4
1.7
18.7
0.6
5.7

0.09

19.0
30.5
9.1
14.7

8.9
24.2
6.3
3.5
2.5

3.1
6.9
0.3
16.4

21.3
18.5
0.06
14.9

0.25

0.15

- .
5.1
9.1
5.1
33.1
19.5
1.9
10.3
6.1

22.5
13.7
10.4
12.5

-

9.8

5.5
28.0
6.7
0.7

0.05

0.22

a/ Addltlonalvalues of the annual genetlcally slgnlflcant dose:
Canada, 0.26 mSv (1979) [M3]; Sultzerland. 0.23 mSv (1978) [P14].

T a b l e

28

Mean qonadal and genetlcally slqnlflcant doseIn the Russlan Federatlon[K19. K20]

Year

Annua 1
per caput
gonadaldose(msv)

Genetlcallyslgnlflcant
dose
(mSv)

T a b l e

29

Mean e f f e c t l v e dose e p u l v a l e n t
f o r d l f f e r e n t dlagnostlc x-ray examlnatlons

Chlna

France

Italy

Japan

Spain

USSR

1981
[28]

1982
[M21

1983
[PI]

1986
[n14,M181

1986
[V41

1982
[Ngl

Skull
Cervlcal splne
Dorsal s p l n e
Dorsal lumbar s p l n e Lumbosacral s p l n e
7.2
Chest
Radlographlc
0.21
P h o t o f l u o r o s c o p l c 3.40
Abdomen
4.5
Upper G I
Radlographlc
Fluoroscopic
0arlum enema
Radlographlc
Fluoroscoplc
Cholecystography
4.3
Hysterography
UrogramP e l v l s and h l p
Extremitles
Computer tomography Dental f /

1.35
1.35
2.24

0.22
0.14
1.34

0.09
0.30

0.2

0.17 g/0.23 g/
3.55

4.73

2.51

0.60

0.28

0.18
0.25
1.92
9.27

0.05

0.16

0.29

1.5

lxamlnatlon

a/

2.56
6.73

-

7.21
4.78
10.42
1.59

) 1.0

1
)

-

-

1.2

)

-

1

2.0

)

8.97
9.96

)

UnltedStates
1980
[HI]

e/
4.42 e/

0.36
1.15
1.52
1.52
9.45

0.13
0.20

-

1-27
0.07

-

0.56

b/

2.44

) 10.2

-

-

0.55

7.07
3.20

0.70
0.25

1

7.0
2.3
0.1
5.0

3.55
14.40
1.97

4.6

2.51
1.45
0.01

1.6
0.6
0.1

1.9

a/ Dose does n o t l n c l u d e component f o r bone marrow.
b/ P/A p r o j e c t l o n o n l y .
C/

P/A and LAT p r o j e c t l o n .

d/ A/P p r o j e c t l o n o n l y .

g/ A/P and LA1 p r o j e c t l o n .
!/ Values o f mean e f f e c t l v e dose e q u l v a l e n t f o r d e n t a l x - r a y e x a m l n a t l o n s :Japan. 0.03 ( l n t r a - o r a l ) ; 0.04 ( e x t r a - o r a l ) ; USSR. 0.01 ( I n t r a - o r a l ) [W9];U n l t e d Klngdom. 0.02 ( l n t r a - o r a l ) ; 0.03 ( e x t r a - o r a l ) ; 0.08 (pantomographlc)[U4, S151.

T a b l e

30

Annual per caput doses from dlaqnostlc x-ray examlnatlons
bv level of health care
(mSv)

Level
of
healthcare
IAnnualper caput
effectlve
dose
equlvalentAnnualgenetlcallyslgnlf lcant
dose

Average

1 .O

0.3

Chlna
1983
1slam.Rep.
of Iran a/ 1980
Iraq a/Turkey a/
1977

0.4

0.09

[zlll

0.09
0.05
0.05

[s191

CountryYear

Reference

Canadaf Inlandf rance

Germany,
fed.Rep.
Italy
Japan
Netherlands
RomanlaPolandSpaln
SwedenSwltzerland
Un l ted
K 1 ngdom
UnltedStates
USSR

II

I11

Indla a/Thalland a/IV

No data

g/

Iu4 1

1972
1970

Ooes not Include fluoroscopy. If frequency of examlnatlons Is
1/10 of level I but fluoroscopy ls 30-70% of t h e total. then theeffectlve dose equlvalent and the genetlcally slgnlflcant dose
may be comparable to those of health care level I.

T a b l e

31

Olaqnostlc x-ray examlnatlon frequency
and contrlbutlon to per caput absorbed dose
In countrles of level of health care I

AnnualEffective
examlnatlons dose equivalent
per caput
per examlnatlon(msv)

Examlnatlon

Sku1 1
Cervlcal splne
Dorsal splne
Dorsal lumbar splne
Lumbosacral splne
Chest. radlographlc
Abdomen
Barlum meal and enema
Cholecystography
UrogramPelvls and h l p
Extremltles
Computer tomography
Other
Oental

0.050
0.020
0.013
0.013
0.025
0.240
0.55
0.070
0.013
0.024
0.038
0.157
0.010
0.096
0.250

0.15
0.30
1 .OO
1-00
1 .50
0.10
1 .OO
8.0
1.5
3.5
1.5
0.10
1 .O
1 .O
0.03

< 0.003 (<I)

0.008
0.007
0.013
0.013
0.038
0.024
0.055
0.560
0.057
0.084
0.020
0.016
0.010
0.096
0.008

Total (rounded)a_/Annualgeneticallyslgnlflcant
dose a/(mSv )

Annua 1
per caput
cffcctlve
dose equlvalent(mSv)< 0.003 (<I)
0.006 (2)0.006 (2)0.045 (IS)0.006 (2)0.024 (8)0.066 (22)0.006 (2)0.060 (20)0.006 (2)0.030 (10)< 0.003 ((1)

1 .O

0.3

Percentage glven In parentheses.

T a b l e

32

Estlmated effectlve dose equlvalent and genetlcally slqnlflcant dosefrom dlaqnostlc medical radlography world-wlde

Annua 1
Levelofhealthcare

Populatlon(ml 1 1 tons)

Annualper caput
Annualeffectlve
genetlcallyslgntflcant
dose
equivalent
dose
(~SV)
(mSv)

Total

collectlve

effectivedose
equlvalent(thousandsof man Sv)

1760

METHOD 2
I-IV

b/

5000

1 .O

0.3

5000

a/ Method 1 assumes that in levels 1 1 - I V dose 1s related to
the frequency and rate of examlnatlons.

b/ Method 2 assumes that increased dose from fluoroscopy Inlevels 11-IV countrles makes absorbed dose comparable tolevel I.

T a b l e

33

Estlmated annual dose from dental radloqraphy world-ulde

Level

Populatlon(mllllons)

Total

AnnualAnnualcollectlve
per caput
effectlve
effectivedose
doseequ\valent equlvalent(thousands(mSv)
of man Sv)

5000

Genetlcallyslgnlficant
dose
(uSv)

17.4

a/ Data from Poland and United Kingdom [H20. K5. J1. U4. US].
-T a b l e

34

Occupattonal exposures from dlaqnostlc x-ray examlnatlons(msv)

Average annual

dose equlvalent (mSv)

Category

MEDICAL
Radiologists
CanadaJapan
NorwaySultzerland
Unlted Klngdom
Unlted States
Technologlsts
CanadaJapan
Unlted Klngdom
Unlted States
NursesCanadaJapan
Unlted Klngdom
Alder, porters
CanadaUnlted Kingdom
Physlclsts
CanadaNoway
Unlted Klngdom
All medlcal workers
Japan
Poland a/
Un l ted Kt ngdom
DENTAL (all workers)
Austral la
Canadaf ranceSwltzerland
United Klngdom
Unlted States b/

a/

-b/

1966-1978.
Earller values: 1.1 (1960); 0.6 (1970) [K23].

Reference

T a b l e

35Frequency o f d l a q n o s t l c n u c l e a r m e d l c l n e e x a m l n a t l o n s( p e r 1000 p o p u l a t t o n )Numbers I n p a r e n t h e s e s l n d l c a t e p e r c e n t o f t o t a lAustral l a

Chlna

1980

1981
[z61

1981

14.1 ( 1 0 0 )Examlnatlon

[us]
Braln
Btllary
Llver/spleen
Bone
PulmonaryT h y r o l d a/
Renal
Tumour/abcess
Cardlovascular
Other

1.5
0.1
1.7
2.0
1.2
0.8
0.2

Total

8.0 (100)

0.6 (100)

Poland1981[s25l

U n l t e d Klngdom
1982[W8, W91

Examlnatlon

Denmark

[us1

1985
[E21

(18.4)( 1.7)(21.5)(24.4)(14.7)(10.5)( 1.9)

0.1 ( 1.7)
0.4 ( 5.2)

Unlted States
1982
[us I

14.3 (100)

b/

Braln
Blllary
Llver/spleen
Bone
PulmonaryT h y r o l d a_/
Renal
Tumaur/abcess
Cardlovascular
Other

Total

2.2

(100)

a/ T h y r o l d scans and u p t a k e s .
b/ A d d l t l o n a l r e p o r t e d v a l u e s
F l n l a n d (1982).

17.7 [T3];

6.0

(100)

32.6 (100)o f t o t a l frequency: Canada (1981).
France (1982). 8.7 [ 8 9 ] .

49.0

[Cl];

T a b l e

36

Annual number of dlaqnostlc nuclear medlclne examlnatlons
In the Unlted States(thousands)

Braln
Hepatoblllary
Llver
Bone
Resplratory
Thyroid (uptake
and scans)
Urlnary
TumourCardlovascular
Other
Total a/

726
(4)

3339
(16)

3510
(17)

4803
(22)

6406
(29)

6374
(29)

7405
(32)

a/ Flgures In parentheses refer t o number o f procedures per 1000 populatlon.
-

T a b l e

37

Type and percent of dlaonosttc nuclear medlclne examlnatlons
In some western hemlsphere countries. 1981-1982[I71

Country
BrazllColombla
EcuadorEl Salvador
HexIcoPeru
Unlted States

Thyrold

Hepat lc/
Blllary

50
20
60
40
30
50
9

10
25
15
30
25
15
22

Braln

Bone

15
10
10
20
10

10
20
5
10
15
25
24

11

T a b l e

Lungs

Other

5

10
15
10

10
20
16

10
18

38

Annual freouency o f dlaqnostlc nuclear medlclne examlnatlons(per 1000 populatlon)- - --Country

1970-1972

1973-1975

1977-1979

1980-1982

Reference- - -Austral laAustrlaBulgaria
Burma
CanadaChina
Cuba
Denmark
FinlandFranceJapan
PolandSwedenUnlted Klngdom
Unlted States b/
USSR
a/
b/

-

4

8
18
13

0.1

0.2
49
0.6

0.8
8

0.8
14
5

8

12

15

16

11

29

1985 value.
Earller value: 4 (1966).

14 a/
18
9
8
2
15
7
31
4

W8. US
WB
WB
US
C1
Z5
U5
US.WB.E2
73
89
MIS. H9
S25
US.W8
W8
M3 1
V7

T a b l e

39

N u c l e a r m e d l c l n e exarnlnatlons b v l e v e l o f h e a l t h c a r e

Level
of
health
care

I

II
b/
-

Annualexamlnatlons
p e r 1000
populatlon

Country

75 a/
57 a/
76 a/
20 a/
71 a/

A u s t r a l l a (1980) [US]Austrla(1971) [ W l ]B u l g a r l a (1980) [W7]Canada(1981) [C2]
Denmark(1987) [E?]
Flnland(1982) [ T 3 ] )France (1982-87) [B9. P11)
German Oern-Rep.
Sweden(1982) [W8.US]
U n l t e d Klngdom (1982) [W8]
U n l t e d S t a t e s (1982) [HZ51

8
18
13
49
14
18
9
8
IS
7
32

160 a/
122 a/
50 a/
160
31 a/

Rounded average

16

160

801 l v l aBrazllChlna
Colombla
Cuba
EcuadorMexlcoPhlllpplnes
Uruguay
Rounded average

111

-b /

800

Burma
Indla
Malaysta
Thalland [KIT]Rounded average

IV

b/

.

Populatlon
p e r scannero r camera(thousands)

2300

BangladeshIndones l a
Nlgerla [ f l ]Paklstana/ E s t l m a t e d f r o m t h e number o f exarnlnatlons.
b/assurnlng 1000
exarnlnatlons a n n u a l l y p e r machlne [W8. W9].
Except f o r r e f e r e n c e d e n t r l e s . t h e d a t a were o b t a l n e d
between 1918 and 1984 and p r o v l d e d t o UNSCfAR b y t h e IAEA.

T a b l e

40

E s t l m a t e d average n u c l e a r m e d l c l n e e x a m l n a t l o n s
l e v e l o f health care

Level
of
healthcare

Annualexarnlnatlons
per1000
populatlon

Populatlon
p e r scannero r camera(thousands)

a/ E s t l m a t e d from the number o f machines,
assurnlng 1000 examlnatlons
p e r machlne [W7].

annuallyT a b l e

41

Estimated world-ulde dlaqnostlc nuclear medlclne examlnatlons
and number of machlnes
Numbers ln parentheses lndlcate per cent of total(mllllons)

Camerasorscanners

Annua 1dlagnostlc
examlnatlons(mllllons)

5000 (100)23500 (100)23.5 (100)

Level
of
healthcare

Populatlon

Total

T a b l e

42

Age and sex dlstrlbutlon O f Datlents underqolnq
dlaqnostlc nuclear medlclne examlnatlons[S25. UlO]

8raln

ihyrold

CardiovascularPulmonary

Age and sex
PolandUnltedStatesPolandUnltedStatesPolandmale
4.9
female
4.4
both
9.3
15-29
male
10.3
female
8.1
both
18.4
male
11.1
30-44
female 11.4
both
22.5
45-64
male
21.0
female 15.5
both
36.5
> 64
male
7.1
female
6.2
both
13.3
Allagesmale
54.4
45.6
female
100.0
both

1.4
1.3
2.7
4.4
2.6
11.0
4.9
7.7
12.6
14.4
15.1
29.5
19.7
24.5
44.2
45.5
54.5
100.0

0.4
2.2
2.6
3.3
20.4
23.7
3.9
30.2
34.1
5.2
29.7
34.9
1.0
3.7
4.7
13.8
86.2
100.0

0.1
1.3
1.4
2.6
14.0
166
4.5
23.0
27.5
7.1
28.5
35.6
3.6
15.3
18.9
17.9
82.1
100.0

1.5
0.9
2.4
16.7
6.3
23.0
22.4
7.1
29.5
31.6
6.4
38.0
4.2
2.9
7.1
6 4
23.6
100.0

< 15

Llverhpleen

Rena 1

UnltedStatesPoland

-

7.3
1.6
8.9
22.4
5.4
27.8
13.3
11.9
25.2
6.3
6.4
22.7
11.0
4
15.4
70.1
29.9
100.0

1.5
0.8
2.3
8.1
4.3
12.4
33.3
20.4
53.7
16.2
1.4
31.6
59.1
40.9
100.0
Bone

UnttedStates

2.8
5.3
8.1
6.0
8.8
14.8
18.2
18.9
37.1
17.5
22.5
40.0
44.5
55.5
100.0

All examlnatlons

Age and sex
Poland< 15

malefemale
both
15-29
male
female
both
30-44
male
female
both
45-64
male
female
both
> 64
male
femaleboth
All ages male
female
both

2.3
2.4
4.7
6.4
6.9
13.3
9.5
10.5
20.0
22.4
21.5
43.9
8.8
9.3
18.1
49.5
50.5
100.0

Unlted Poland
States
0.1
0.1
3.4
3.1
6.5
5.4
5.7
11.1
18.8
21.7
40.5
19.5
22.3
41.8
47.2
52.8
100.0

4.0
5.6
9.6
11.2
9.4
20.6
11.5
12.9
24.4
17.7
17.4
35.1
4.3
6.0
10.3
48.5
51.5
100.0

Unlted Poland
States

UnltedStatesPolandUnltedStates

1.4
2.1
3.5
5.7
5.7
11.4
10.7
10.0
20.7
21.5
15.8
37.3
15.7
11.4
27.1
55.0
45.0
100.0

1.1
0.9
2.0
2.9
2.3
5.2
3.6
6.4
10.0
14.9
23.9
38.8
20.5
23.5
44.0
43.0
57.0
100.0

2.0
3.3
5.3
6.4
15.4
21.8
7.1
21.7
28.8
11.7
24.0
35.7
3.3
5.1
8.4
30.5
69.5
100.0

0.9
0.7
1.6
3.3
4.9
8.2
5.2
8.7
13.9
15.8
21.6
37.4
11.0
21.9
38.9
42.0
58.0
100.0

5.2
3.2
8.4
11.3
11.6
22.9
8.7
15.0
23.7
13.3
22.9
36.2
4.3
4.5
8.8
42.8
57.2
100.0

T a b l e

43

Averaqe actlvlty used for some comnon nuclear medlclne examlnatlons

Average activity (MBq)
OrganRadiopharmaceutical
Germany Poland
Fed. Rep.
[K2.K3] [S25]

SwedenUnltedKlngdom

a/

%I

In61

Lug]

-

Thyroldb/
Liver/

spleenRenal

Bone
CardlacLung
Brain

99m~c-pertechnetate
1231-lodlde1311-lodlde
99mTc-collold
1 9 8 ~ ~ - c loldol
131 1-Hlppuran
99m~c-OTPA
99~~-glucoheptonate~ ~ ~ T C - O ~ S A
99mTc-phosphate
99mTc-erythrocytes
20111-chlorlde
99mTc-mlcrospheres
99mTc - 0 7 PA
99mTc-pertechnetate
99mTc-glucoheptonatea/ Humbers In parentheses lndlcate ranges where data a r e available.
b/ Addltlonal values from the Unlted States are 237 (37-555), 0.8 (0.3-1.6),- 0.3 (0.04-0.4) for 99m~c-pertechnetate, lZ31-lodlde and 1 3 1 1 - l o d l d e ,respectlvely.
C/ Iodlne-123.

T a b l e

44

Annual collectlve effectlve dose eaulvalent
for In vlvo diaqnostlc nuclear medlclne examlnatlons(man Sv)

China

Finland

Polafid

Sweden

USSR

1982
[T3]

1981
(S251

1983
[J81

Annual collect 1 ve
effecttve dose
equlvalent (total)( m n Sv)
4700

430

2020

Annual per caput
effecttve dose
equlvalent
(m~v)

0.090

0.057

Examlnat ton

1981
[26]
Brain
Hepatobiltary
Llver/spleen
Bone
PulmonaryThyrold
Renal
Tumour/abcess
Cardlovascular
Other

a/

1981
(v71

UnltedKlngdom
1982[H201

UnltedStates
1982
[n30]

540

8700

950

32000

0.060

0.034

0.017

0.14

a/

I3
924
4
3740
1
12

0.005

Assumes that Shandong Provlnce Is representatlve.

T a b l e

45

Radtonucltde contrlbutlon to annual Collectl~e effectlve dose epujvalentsfrom dlaqnostlc nuclear medlclne(per cent)

Chlna

Flnland

PolandSweden1983
IJ81

UnltedKlngdom
1982[HZO]

UnltedStates
1982
[H30]

1981
[Zb)

1982
[T3]

1981
[SZS]

51
47
2

2

77

96
2

33
b2
5

89
4
7

b8

RadlonuclldeTechnetl um-99m
Iodlne-131
Other

23

I1
IS a/

--

a/

Two-thlrds of thls Is due to thalllum-201.

T a b l e

46

Annual per caput doses
from dlaqnostlc nuclear medlclne examlnatlons
(msv)

Level
of
healthcare

I

Per caput
CountryYear

dose
equlvalent
Australla
1980
0.02
Denmark
1985
0.05
Flnland
1982
0.09
Japan
1982
0.04
Sweden1983
0.06
Un\ted Klngdom 1982
0.01 1
Unlted States 1982
0.14
USSR
1981-1982 C.03-0.04
0.05 a/AverageIIeffective

Chlna

a/ Population

1981

0.005

Annualgeneticallyslgnlflcant
dose
equlvalent

Ref

0.004
0.003
0.19

0.01 b/I261

welghted average collectlve effectlve dose
equlvalent = 0.067 mSv.
b/ Assumes genetlcally slgnlflcant dose ls approximately 20% ofeffectlve dose equlvalent.
C/ N O data avallable.

T a b l e

47

Estlmated collectlve effectlve dose eaulvalentand genetlcally slgnlflcant dosefrom In vlvo dlaqnostlc nuclear medlclne

Level
of
healthcare

Populatlon

Annualper caput
effectivedose
equlvalentAnnualgenetlcallyslgnlflcant
dose(mllllons)

(msv)

(msv)

Total

Annualcollectlve
effectlve
dose
equivalent(thousandsof man Sv)

5000

74

T a b l e

48

Average annual lndlvldual occupatlonal doses
for nuclear medlclne technologlsts from dlaqnostlc nuclear medlclne

AustrlaCanadaFranceNorwayUnltedK 1 ngdom

Nuclear medlclne
technologlsts:
Average annual dose (mSv)
Collectlve dose (man Sv)

1978
[US]

1951-1983[S20.S21]

1979
[US]

1983
[W17]

1984
[HZ01

0.4
0.4

2.0

0.5
l .2

0.6
0.3

0.3-1.4

T a b l e-

49

Radlatlon therapy treatments In Canada a/
[Cl I

Year
Type oftreatment

Superflclal x ray
Deep x ray
CobaltRad 1 umOther

19 098
109 7023 3 3 355
2 202
103 913

12 0 2 820 925274 4 7 0
2 199
314 187

11 8 2 7
29 3 9 2
244 4221 289
375 2 7 0

Total

568 270

6 2 3 809

6 6 2 197

a/ For elght provlnces, uhlch comprise approximately
91.5% of t h e Canadlan populatlon.

T a b l e

50

Estimated a n n u a l number and t y p e o f cases t r e a t e d b y r a d l a t l o n t h e r a p y
l n some w e s t e r n hemisphere countries
[u71

New
cancercases
treatedCountryNewcancercases
treatedulthradlotherapy

Type o f c a s e t r e a t e d ( X )BreastGynaeLymph- c o l o g phoma
Ical

Other
cancers

Nonmallgnant

17 (Colombla)

and 10Dlgestlve

Columbla
Costa R l c a
EcuadorE l Salvador
MexicoPeru
Unlted States
Venezuela

A d d l t l o n a l v a l u e s : head and neck. 1 0 ( V e n e z u e l a ) ;( E c u a d o r ) ; l u n g s , 4 (Colornbla) and 1 0 ( U e x t c o ) .

T a b l e

sktn.

51

Number o f m e q a v o l t a g e radiotherapy u n l t s I n t h e U n l t e d S t a t e s
and a n n u a l number o f new o a t l e n t s p e r u n l t[KlS, R7]

Year

CobaltLlnearacceleratorsand b e t a t r o n sNewpatlents
per u n l t

T a b l e

52

Radlatlon therapy experlence by level of health c a r e

Annual procedures
per mllllon populatlon
Level
ofCountry
health
care

I

Year

Hachlnes
per mlll ton
populatlon&/

Reference

US1
nb, ni31

us I
031
Kl4. Rb]

8razllChlle
EcuadorMexlcoPeru
Venezuela- 2400

- 400

- 600

- 400

1981
1981
1981
1981
1981
1981

Average

I11

Unsealedradlonuclldes

Argent lna
Oenma r k
FranceGermany.
Fed.Rep.
Japan
SwedenUnlted Klngdom
Unlted States
Average

I1

Brachytherapy
and teletherapy

Burma
lndla
Srl Lanka
Sudan

1978
1976
1978
1985

b
125 Q/
350
7 0 b/-

2-

I00 b/

Average

0.4

a/ Data also lndlcate approximately 200 new patlents ( o r 2 5 0 total patlents)
per machlne annually. Hachlnes lnclude teletherapy, cobalt and accelerators.

b/ Estlmated based on 2 5 0 patlents annually per machlne.

T a b l e

53

lstlmated radlatlon therapy actlvitv bv level of health care[n2i]Annual procedures
per mllllnn populatlon
Levelofhealthcare

Brachytherapy
and teletherapy

a/ Cstlmates

Unrealedradlonuclldes

Hachlr~es
per mllllon
populat lona/based on percentage of brachytherapy and teletherapy procedures.
b/ Cstlmates based on regresslon from nuclear
medlclne actlvlty.

T a b l e

54

Estlmated uorldwlde radlatlon therapy procedures and machlnes
IMZ'llAnnual procedures orcourses of treatment
Levelofhealthcare

Populatlon(rnllllons)

Total

BrachyUnsealed
therapy
radloand teletherapy
therapy(thousands) (thousands)

5000

4300

T a b l e

Number ofmachlnes

18000

720

55

Estlmated qenetlcally slqnlflcant dosefrom radlatlon therapy

Level
of
healthcare

Populatlon(rnllllons)Annua 1
geneticallyslgnlflcant
dose
(msv)

-a/ Average of flve reported values [HIE, US].

T a b l e

56

Average annual lndlvldual occupational dose from radlatlon therapy(msv)

Australla

CanadaNorway

1978

1984
[C3]

1983
[Wll]

Category[us]

UnltedKlngdom
1981[HZ01

UnltedStates1975[US]

Beam therapy
Rrachytherapy
Radlotheraplsts
Anaesthetlsts
OR nurses
Ward Nurses
Laboratory staff
Mould room staff
Physlclsts
All workers
Collectlve dose (man Sv)

0.4

1.05

60

T a b l e

57

Estlmate of uorld-ulde collectlve effectlve dose equlvalentand genetlcally slgnlflcant collectlve dosefrom medlcal uses of radlatlon(thousands of man Sv)

Annualcollectlve
effectlve
dose
equlvalentAnnualgenetlcallyslgnlflcant
collectlve
dose

Olagnostlc medlcal
OentalDlagnostlc
nuclear rnedlclne
Radlatlon therapy

1800-5000
17500-1 500
0.14

74

15
27

Per caput (mSv)- 0.4-1 .O- 0.1-0.3

SourceT a b l e

58

Occupational exDosure from medlcal uses of radlatlon

Country

CanadaFranceGermany.
FederalRep.
Japan
NorwayUnltedKlngdom
Unlted States

Year

1974
1984
1974
1979
1984
1978
1983
1984
1960
1970
1980

Annualaveragedose

collective

Annual(m5.v)(man Sv)

0.3
1.3

10.5
7.2
29

dose

Collective
dose
per rnllllon
population(man Sv)

0.3
0.8

1.1
0.5
1.3
0.7
1.9
1.1

0.1

27
55
5.8
28
580
500
4 10

0.4
0.5
1.4
0.5
1 .8

Reference

U4
C3, W17
U4
U5
N12

n1 9
W17
HZ0
K23
K23
K23

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