internal dosimetry of pure beta emitters other than tritium

7/26/2019 Internal Dosimetry of Pure Beta emitters other than Tritium

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Internal Dosimetry of Pure

Beta emitters other than

Tritium


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1...Introduction

2Whole-body counting system for measuring9

Sr via bremsstrahlung

3Strontium egistry

!"etabolic "odelling of Strontium

#$eneral %io&inetic "odel of Strontium

'(nalysis of strontium metabolism in humans on the basis of the )echa river data

*"aterials and methods

*.1.+,osed oulation follo-u

*.2.Whole-body measurements of 9/Sr

*.3.%iologica l elimination rates

*.!.9/Sr retention

*.#.esults

*.#.1.(ge eriod 1/ to 2/ years

*.#.2.(ge eriod 2/ to !/ years

*.#.3.(ge eriod over !/ years

0(45 +S+(6 4 I)+(7 54SI"+)8 WI) S)4)I" :%ased


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0.3.'.%ioassay for adiostrontium

0.3.*.+,creta %ioassay )echni=ues for 9/Sr

0.!.In >ivo "easurement of 9/Sr

0.#. ecommended ;eriodic %ioassay "onitoring ;rotocol

0.'.Secial "onitoring for Susected +,osures

0.*.(ssessment of Internal 5ose +=uivalent

0.0."anagement of Internal 6ontamination 6ases

0.9.)heraeutic (ctions

0.1/.7ong-)erm %ioassay ollo- "onitoring (fter an Inta&e

9( "45+7 4 )+ )(S+ 4 6(76I" (5 S)4)I" )4 )+

+)S

9.1."()+(7 "45+7S

9.2.+)(7 "45+7S

9.3."45+7 ;+5I6)I4S

9.!.)+ S)4)I" 64)+) 4 "( %4+S

9.#."aterials and "ethods


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11.#.4ther carbon comounds

Refrences

Appen!" 1 ----A#e-spec!f!c $r%nsfer r%$es (!n&erse %'s) for s$ron$!m ($%en from P*+!c%$!on 67

Appen!"----r-90 ose coeff!c!en$s (An%+'.e *' ICRP comp$er pro#r%m) !n %++ Poss!*+e c%ses

Appen!"/----C-1 ose coeff!c!en$s (An%+'.e *' ICRP comp$er pro#r%m) !n %++ Poss!*+e c%ses

Acknowledgement:

The author is thankful to all official of HPU unit (KGS 1&2) for valuable

suggestions and T! KGS and Kno"ledge #anage$ent% P!' H for suort

to carr* out this "ork+


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Internal Dosimetry of Pure Beta Emitter other than Tritium

nternal ,osi$etr* of Sr-./ (0eta e$itter of nerg* /+34#e5)

1...Introduction6 Strontiu$-./ is a 7bone seeker7 that e8hibits bioche$icalbehavior si$ilar to calciu$% the ne8t lighter grou 2 ele$ent+ 9fter entering theorganis$% $ost often b* ingestion "ith conta$inated food or "ater% about :/;


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./Sr is long-lived bone-seeking radionuclide "ith a long biological residence ti$ein the bod*+ The "orld list of data on strontiu$ in $an "as restricted to a fe"

e8eri$ental findings "ith a single intake% infor$ation on global fallout and the$easure$ents of dial ainters+ 9 large $ultitude of $easure$ents of 7Sr in hu$an bod*for the residents of the Techa river (Southern Urals% Dussia) conta$inated b* fission

roducts in 1.3.-1.4 has been ublished in oen literature onl* recentl* (KoEheurov%1..3F ,egteva et al+% 1..3)+ The necessit* of dose reconstruction fro$ long-livedradionuclides for the oulation living on the territories conta$inated as a result of

!hernob*l 9ccident calls the utilisation of the Urals e8erience to oti$ise the efforts+9n anal*sis of a uniCue and abundant Urals data set on strontiu$ in hu$ans resents alsoa great interest for general uroses of retrosective dosi$etr*+Poulation e8osure in the Urals occurred as a result of failures in thetechnological rocesses at the #a*ak lutoniu$ facilit* in the 1./Bs+ !onstructionof the #a*ak facilit* began in 1.3 and "as co$leted in 1.3


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2!hole"#ody counting system for measuring $%&r 'ia #remsstrahlung

Since 1.:3 the large scale investigations of the ./Sr content in the skeleton ofTecha riverside residents "ith the "hole bod* counting s*ste$ S!H-.+1 "erestarted+ 9 detailed descrition of S!H-.+1% of the $easure$ent rocedure andresults "ere given els"ere (KoEheurov% 1..3)+ The shielding for the "hole-bod*counter "as $ade of cast iron rings "ith a "all thickness of 2// $$+ The innersurface has linings of lead ($$)% cad$iu$ (1+ $$)% and coer (1 $$)+ ourPhos"ich detectors are used for $easuring+ The geo$etr* of $easure$ent is asfollo"s6 the detectors are fi8ed in the central vertical lane "ith a A/I inclinationto"ards the vertical+ The distance bet"een the a8es of each air of detectors is A c$at the base+ >n the bed fra$e% fabric is stretched "hich caves in under the "eight ofthe bod*in such a "a* that the $ediu$ lane of the bod* is at a distance of 2 c$fro$ the detectors+ ,uring the $easure$ent the robandBs bed is $oved throughthe detector arra*+ The scanning length is 2 $ "ith stos at the ends lasting 1/=

each of the "hole $easure$ent ti$e+ The $otion is controlled b* i$ulses fro$the anal*Eer real-ti$er+ The duration of the $easure$ents is 2/ $in+ The scanningdevice used in S!H-.+1 is discussed in (Jaitsev and KoEheurov% 1.:


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(&trontium )egistry

The $easure$ents of 7Sr in hu$ans for the residents of the Techa river "erestarted in 1.1+ The first findings "ere 7Sr concentrations in different bones receivedfro$ autosies (Table 1)+ Since 1.4/ the surface beta-activit* on the teeth has been$easuredF this "as $ade ossible "ith the detectors suitable to erfor$ such$easure$ents in the $outh of a erson (KoEheurov% 1..3)+ ro$ 1.42 through 1.:.dail* urinar* e8cretion "as esti$ated b* radioche$ical $ethods+ 9nd since 1.:3 theTecha river residents have also been e8a$ined for their bod* burdens "ith the "hole-

bod* counter (KoEheurov% 1..3)+ n arallel "ith "hole-bod* counting the$easure$ents of beta-count of forehead bone are carried out+ 9bout A/%///$easure$ents have been erfor$ed on $ore than 13%/// ersons fro$ theconta$inated+ 0oth $en and "o$en of all ages have been $easured+ This has given auniCue e8erience of the arrange$ent of individual $onitoring of ./Sr

Ta#le 1. Techa )i'er &trontium )egistry.

*easured 'alues +um#er of +um#er of su#,ects Period of

measurements measured o#ser'ation

&r"$- whole"#odycontent

2/0-- 1/2-- since 1$

Tooth #eta"count (-/2-- 10/(-- since 1$3-

4orehead #eta"count 2(/1-- 12/(-- since 1$3

&r"$- urinarye5cretion

2/$1- 1/03 1$32"1$$

&r"$- concentrationin #one

(0- 13- 1$01"1$(


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schedules of intake based on the $etabolic ara$eters of Deference #an to the sets ofdata+ Thus% checking of $odel fitness and ara$eter verification are carried out+

9s a starting oint for ara$eter fit the general vie" of so$e age-deendent functions "asidentified b* co$bining relativel* e8tensive infor$ation concerning thedevelo$ent of the hu$an bod* "ith the findings of e8eri$ents on different seciesof ani$als+ Then the available sets of hu$an data "ere deter$ined for the $ore reciseesti$ates using e$irical fitting techniCue+ 0esides the Techa river data% the infor$ationon strontiu$ in hu$an bone fro$ global fallout ('eggett et al+% 1.


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Table 2+ The co$arison of strontiu$ e8cretion rate esti$ates in late hase of

retention for hu$ans+

Stud* descrition #uller% 1.:/ ,egteva et al KoEheurov% 1..3

Sa$le

infor$ation - se8

- age% *r

- 7Sr bod*

burdens% k0C

. lu$iniEers

1 # L <

22 - 31

1+


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are of $aor interest to the reconstruction of dose to the red bone $arro" and bonesurfaces of the $e$bers of the Techa river cohort "hich could give a ossibilit* of

direct radiation risk assess$ents for long-ter$ chronic e8osure conditions+

06eneral Biokinetic *odel of &trontium6-

The alkaline earth ele$ent strontiu$ % radiu$ follo"s the $ove$ent of calciu$ inthe bod* but e8hibit different rates of transfer fro$ that of calciu$ due to

discri$ination b* biological $e$brane and bone $ineral+ ollo"ing are thei$ortant features of these $odels+ Skeletal activit* first deosits on bone surfaces+Deturn to las$a or $igrates to e8changeable bone volu$e "ithin a fe" da*s+So$e activit* leaves e8changeable bone volu$e is assu$ed to return to bonesurfaces+ De$ainder is assigned to non e8changeable bone volu$e+ Graduall*$oves to las$a b* bone resortion+Soft tissue is reresented b* A co$art$entsST/% ST1 and ST2+ or radiu$ and uraniu$% the liver is kineticall* distinct fro$other soft tissues+ 8cretion of Ureniu$ through kidne* and e8change of activit*

bet"een las$a and kidne* tissues is also considered+


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90r *o' *ren 2%&e *een performe s!nce 197 s!n# % 32o+e-*o' con$er,

%n $2ese 2%&e m%e !$ poss!*+e $o es$!m%$e %#e-spec!f!c +on#-$erm re$en$!on %n

eli$ination rates for $en and "o$en+ Degarding the retention that correlated "iththe resective $aturation ages% distinct se8 differences have been observed foradolescents% "hereas onl* ost$enoausal "o$en sho"ed a shar increase of theireli$ination rates+ There "ere no differences concerning the reroductive ages+ >ure8eri$ental findings have a clear h*siological interretation and can be used todevelo $etabolic $odels for bone-seeking radionuclides

The releases of liCuid "astes "ith 1/1: 0C of fission roducts fro$ the #a*aklutoniu$ roduction co$le8 (Southern Urals% Dussia) during the *ears 1.3. to1.4 resulted in a conta$ination of the Techa river and its floodlands+ or the 2n the basis ofthese results% it can be suggested that se8 differences in long-ter$ retention (ig+ 2)are redo$inantl* conditioned b* eli$ination rocesses (for those over / *earsold) and b* utake rocesses (for *ounger age grous "ithout se8-deendent

eli$ination varieties)+


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t is obvious that the differences in ./Sr retention result in different doses absorbedin target tissues+ This fact stresses the need to understand the h*siological basis of

the observed heno$ena and to take it into account in the develo$ent of ne"$etabolic $odels+ 9n* further anal*sis reCuires the consideration of three searateage eriods6 (i) fro$ 1/ to 2/ *ears old (intensive bone gro"th and for$ation)F (ii)fro$ 2/ to 3/ *ears old (stabiliEation of aosition and resortion rocesses)F and(iii) $ore than 3/ *ears old (the involution of the skeleton)

*.#.1.(ge eriod 1/ to 2/ years

9ll investigated ersons had assed this age eriod during the "hole-bod* counter$easure$ents% but the ./Sr retention for eole aged 3/;/ *ears reflected utake

rocesses that had occurred A/ *ears before in their teens+ Ph*siological rocessesin adolescence are connected "ith se8ual $aturation% and there are se8 differencesconcerning the gro"th and develo$ent of bo*s and girls% resectivel*+Girls+ The$a8i$u$ skeletal gro"th rate in length takes lace "ithin the 2 *ears u to$enarche+ The individual bone age has the closest connection "ith $enarchalage+0* analog*% it has been calculated the Oage relative to $enarche (9D#) foreach investigated "o$an as the difference bet"een the age at "hich $a8i$al ./Srintake occurred and the age of $enarche+ 9s seen fro$ ig+ 3a%"hich sho"s ./Srretention to be deendent on 9D#% the $a8i$u$ is observed shortl* before$enarche and then the value re$ains constant for al$ost 2/ *ears+ The analogous

deendence obtained for annual gro"th rate is resented in ig+ 3b+ Theco$arison of the t"o curves sho"s that a constant value of utake(corresonding to the level for an adult "o$an) is established instantaneousl* "ithth th t i ti t ft hi h l Th f th f


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*.#.2.(ge eriod 2/ to !/ years

This is the eriod of stabiliEation in $ineral bone turnover+9n eCuilibriu$ is

established bet"een aosition and resortion rocesses% and the bone $ass is ketconstant+ or this age eriod% there are no differences in bone turnover bet"een$en and "o$en+ The $ean eli$ination rate for this age grou is 2+42= M /+1=er *ear This value is ver* close to the aositionRresortion rate for co$act


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igure 4a resents the strontiu$ eli$ination rate for "o$en as a function of agebefore and after $enoause+The $ost drastic changes occurr during the last 2 *earsbefore $enoause "hen the eli$ination rate increased sharl* (2+-fold)+9ft d th li i ti t i t th l l f b t 4= f 1


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substantiation to introduce se8-deendentara$eters in the $odel+ n conclusion%the data resented indicate distinct se8 di$orhis$ in the retention of bone-

seeking radionuclides at the eriods of se8ual $aturation and involution+ Thisdi$orhis$ $a* result in different values of absorbed dose for $en and "o$enand should be taken into consideration "ith regard to the develo$ent andverification of $etabolic $odels+ or "o$en% the ages of $enarche and$enoause can serve as individual $arkers for redicting the $o$ents of changesin the ara$eters of $ineral $etabolis$+

D, DS9D!H > TD9' ,>S#TD TH

STD>TU# (0ased on !DP ublication) 6


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facilities+ This use of a ratio can be valid if the nature of facilit* conta$ination iskno"n+

hen Hanford reactors "ere oerating% the otential e8isted for DG co$uter code (Hedengren1.


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or $ost internal dosi$etr* uroses% ./Sr and ./ are the nuclides of concern+These nuclides are found in eCuilibriu$ in virtuall* all circu$stances under "hich

e8osure is likel*+ 9lthough strontiu$ searation oerations have been erfor$edin "hich ure ./Sr $ight be obtained% the raid ingro"th of the ./ deca* roductresults in the secular eCuilibriu$ condition being achieved "ithin about 2 "eeksafter searation+ Thus% even if an e8osure to ure ./Sr occurred involvingsignificant $etabolic utake and internal deosition% "ithin about 2 "eeks ofe8osure eCual Cuantities of both nuclides "ould be resent in the bod*+ Pure ./"as roduced and ackaged in the A2 0uilding during the 1../s (through 1...)+nviron$ental 'evels of ./Sr 6- ,ail* dietar* intake of ./Sr is esti$ated to rangefro$ /+1 to /+3 0CRd (San rancisco to e" ork) according to the United ationsScientific !o$$ittee on the ffects of 9to$ic Dadiation (US!9D 1.


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been used at Hanford+ aste $anage$ent ractices involving strontiu$ fluoride(Sr2) are of articular interest fro$ an internal dosi$etr* ersective% because

Sr2 "as not secificall* included in the !DP lung $odel descritions ofstrontiu$ co$ounds+ The "aste fractionation rocess searated and urified ./Srat 0-Plant% and then converted it into Sr2 o"der% "hich "as encasulated into"elded c*linders at S+ The c*linders re$ain stored in a "ater ool at S+The Sr2 o"der "as selected as the che$ical for$ because of its che$icalstabilit* and onl* $oderate solubilit* (i+e+% its relative insolubilit*)+ This relativeinsolubilit* and lack of secific discussion in the !DP lung $odel $ight be causefor considering Sr2 to be a class or $aterial+ Ho"ever% this is not thought to

be the case+ hile solubilit* studies for Sr2 in si$ulated lung fluid have not beenidentified% Sr2 is onl* $oderatel* soluble on a large scale% having a solubilit*

roduct of A+ X 1/-3 $gRl+ 9 different icture e$erges uon consideration of the$icroscoic scale% as $ight be encountered in hu$an intakes+ 0ecause of the ver*high secific activit* of ./Sr% dosi$etricall* significant Cuantities of Sr2 o"der

have e8tre$el* s$all $asses that co$e no "here near the solubilit* roduct andthus are ver* Cuickl* dissolved in a s$all volu$e of fluid as $ight be found in thelung or G tract+ Hence% ./Sr2 "ould be e8ected to e8hibit class , behavioruon intake+

.(.278take to Blood

The absortion coefficient (f1) used for the G tract absortion of readil*transortable (inhalation class ,) for$s of strontiu$ is /+A% "hich is consistent

ith th d ti f !DP bli ti A/ (1.:.) 4 (1.


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strontiu$ distribution have been develoed b* 'eggett% cker$an% and illia$s(1.


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Table A 6- ./Sr Urine 8cretion ractions


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Table 36 ./Sr ecal 8cretion ractions

.(.0.Internal Dosimetry 4actors for )adiostrontium 6The ./Sr co$$ittedeffective dose eCuivalent coefficients of greatest interest to Hanford internaldosi$etr* are for intakes of 1-Y$- and -Y$-9#9, articles+ 5alues for thesecoefficients% as calculated b* !,% are as follo"s6

Z !lass , inhalation -Y$-9#9, articles6 /+2: $re$Rn!i intakeZ !lass , inhalation 1-Y$-9#9, articles6 /+22 $re$Rn!i intake+!o$$itted dose coefficients for organs and tissues of significance to several

diff t i t k diti t b l t d i T bl ! itt d d ffi i t f


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./Sr at Hanford% the dose coefficients and derived levels are rovided forinfor$ation uroses+

Table 6 Hanford ./Sr ,ose !oefficients for Significant >rgans ($re$Rn!intakea% b)

.(.3.Bioassay for )adiostrontium

The general techniCues and alicabilit* of bioassa* for strontiu$% urine and fecalsa$le bioassa*% in vivo $easure$ent of ./Sr% bioassa* $onitoring rogra$caabilit*% a reco$$ended rogra$% and secial $onitoring needs are discussed inthe follo"ing sections+


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Table .6 ./Sr Urine 8cretion Deference 'evels for !lass nhalation of 1-Y$-

9#9, Particles


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Table 1/6 ./Sr Urine 8cretion Deference 'evels for !lass nhalation of -Y$-

9#9, Particles

The $ini$u$ detectable intakes and co$$itted effective dose eCuivalents


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f isotoe activit* relationshis are kno"n% in vivo "hole bod* counting can be aneffective indicator for the otential resence of strontiu$+ !esiu$-1A: is

freCuentl* used as the indicator% because its fission roduct *ield is co$arable tothat of ./Sr+ Ho"ever% this $ethod is not conclusive and caution $ust bee8ercised because there are rocesses at Hanford "here strontiu$ and cesiu$ haveundergone che$ical searation fro$ each other+ Use of 1A:!s as an indicator of./Sr is $ore full* described else"here+ Dadioche$istr* anal*ses for 1A:!s and./Sr in $edia reresentative of an intake $a* be used in lieu of sule$ental

bioassa* $easure$ents+ This $ethod is $ost aroriate "hen dealing "ithintakes of s$all dosi$etric conseCuence+t is generall* reco$$ended that in vivo $easure$ents be used onl* as indicators

of the otential for strontiu$ being resent% and that evaluations of an* strontiu$intake be based on urine sa$les+


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Table 12+ Hanford 0ioassa* Progra$ !aabilit* for ./Sr in Urine for !lass

nhalation (#,9 [ 1/ d$Rd)

Table 1A+ Hanford 0ioassa* Progra$ !aabilit* for ./Sr in Urine for

Transortable nection and Soluble ngestion ntakes (#,9 [ 1/ d$RdF f1 [ /+A)


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otential intake of $i8ed fission roducts+ 9 "orker scheduled onl* for a "holebod* e8a$ $a* not be recogniEed as having otential e8osure to radiostrontiu$+

f ga$$a-e$itting nuclides such as 1A:!s are also of otential concern% thei$act of $i8tures on otentiall* undetected effective dose eCuivalent $ust also beaddressed+ f other $eans (e+g+% in vivo $easure$ents) are used to $onitor forother nuclides% then annual or biennial urine sa$les should be sufficient to$onitor the ./Sr contribution to dose+

8.6.Special Monitoring for Suspected Exposuresf e8osure to ./Sr has occurred or is susected to have occurred% one or $ore

urine sa$les should be scheduled for investigation uroses+ 0ecause of the highsensitivit* of the urine sa$le anal*sis% even slight intakes of ./Sr resulting ins$all fractions of a $illire$ co$$itted effective dose eCuivalent can be detectedif ro$t sa$ling is erfor$ed+ This also er$its the use of less sensitiveanal*tical rocedures (i+e+% e8edite or e$ergenc* rocessing anal*ses) forreasonabl* accurate dose esti$ates+9s is aarent fro$ Table : and


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curve fitting or deter$ining e8cretion fractions at secific ti$es ost intake+ ,oses$a* be calculated using either an intake value and tabulated dose coefficients or b*

using !,+or Hanford sources% ./Sr and its ./ deca* roduct have generall*been the isotoes of greatest concern for strontiu$ dosi$etr*+ 9s noted in therevious sections%


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dosi$etr*+ or $ore significant intakes% getting t"o or $ore urine sa$les(reresenting actual or si$ulated 23-hour eriods) collected over several da*s or

"eeks follo"ing the intake is referred+ n general% less credence for dosi$etr* islaced on a sa$le taken "ithin the first coule of da*s after an intake co$ared"ith one taken several da*s or $ore after the intake


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background levels in the range of the $ini$u$ detection level for the anal*ticalrocedure+ Using the above $ethod% derived investigation levels "ere calculated

for various ti$es ost intake% and these "ere docu$ented b* letter to the HanfordDadiation Protection Historical iles as cited b* Sula et al+ (1..1)+ ith theissuance of Technical 0asis for nternal ,osi$etr* at Hanford (Sula et al+ 1., co$utercode (Wohnson and !arver 1., at Hanford in 1..2

$A *


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re$odelling and rec*cling fro$ bone and soft tissues to blood+ Trabecular andcortical bone are considered searatel* and bone volu$e is treated as e8changeable

and non-e8changeable co$art$ents+ To $odel the transfer of !a to the fetus% it"as \rst necessar* to deter$ine the content of all co$art$ents of the adult $odelat the beginning of regnanc*% assu$ed to be at age 2 *% as a result of dietar*intake and intestinal absortion fro$ birth+ 9lthough data revie"ed b* !DP sho"variable intakes during childhood% for si$licit* it "as assu$ed that the valuegiven for adults and teenage children of /+. g+d1 alied fro$ birth+ The values offractional absortion% f1% are as given b* !DP6 /+4 for infants in the \rst *ear oflife% /+3 fro$ one *ear to \fteen *ears of age% changing fro$ /+3 to /+A fro$ 1 to2 *+ ,uring regnanc*% intakes and absortion of !a have been sho"n to besigni\cantl* increased+ ntake of 1g+d1 "as assu$ed throughout regnanc*+ >n the

basis of hu$an data% absortion "as assu$ed to increase fro$ /+A at concetion to/+3 at the end of the \rst tri$ester (12 "eeks)% fro$ /+3 to /+4 at the end of thesecond tri$ester (2 "eeks) and re$ain at /+4 throughout the third tri$ester+

Several studies have sho"n a t"o to three fold increase in urinar* e8cretion of !ab* $id-regnanc*% re$aining elevated to ter$+ 0one turnover has been sho"n toincrease during late regnanc* although the e8tent of the increase is not kno"n andthe interretation of $easure$ents of $arkers for bone turnover is uncertain+ or$odeling uroses% urinar* e8cretion "as assu$ed to double over the \rsttri$ester and re$ain at this level until ter$+ 0one turnover "as assu$ed to beunchanged during the \rst tri$ester% to double over the second tri$ester and to

re$ain at this level throughout the third tri$ester+ n the absence of seci\cinfor$ation% all rates to% fro$ and bet"een bone co$art$ents "ere doubled+,esite the substantial changes in !a $etabolis$ during regnanc*% $aternal


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age% based on the data of Guihard-!osta and 'arroche+ Total dail* transfer of !a tothe fetus "as taken to be ten ti$es reCuire$ents on the basis of ri$ate studies in

"hich transfer to fetal blood and return to $aternal blood "ere co$ared+ Deturnto the $other "as taken to be


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#easure$ents of !a in hu$an fetal blood indicate that concentrations areconsistentl* greater than in$aternal blood+ 9 concentration of 1/ $g er 1// $l

"as assu$ed to al* throughout fetal gro"th% basing blood volu$e on therelationshi bet"een fetal bod* $ass and las$a $ass given b* 'uecke et al+Datesof transfer of !a bet"een bone co$art$ents and return to blood fro$ bonesurfaces "ere taken to be the sa$e as used in the !DP $odel for all age grousincluding infants+ Si$ilarl*% the rate of return fro$ soft tissues "as taken to be thesa$e as fro$ ST1 (inter$ediate turnover) in the !DP $odel+ Deturn of !a fro$non-e8changeable bone volu$e "as not considered because bone re$odelling isnot a feature of fetal skeletal develo$ent+ The rate of transfer to bone surfacesfro$ blood "as adusted for each "eek fro$ "eek < to A< to \t the kno"n skeletal!a content+ The rate of transfer to soft tissues "as set so that the !a content of thisco$art$ent "ould not e8ceed 1= of total fetal !a 9ni$al studies in "hich directco$arisons have been $ade and $easure$ents on hu$an tissues have sho"n thatSr is transferred to the fetus less ef\cientl* than !a+ 9n esti$ate of lacental

discri$ination in hu$ans of /+4 "as $ade b* 0r*ant and 'outit b* co$aringstable SrR!a ratios of bones fro$ adults andfro$ stillbirths and ne"born infants+ >n the basis of studies using rats% Ta*lor and0ligh suggested values for hu$ans of /+4 for Sr and /+3 for 0a and Da+ 9 value of/+4 "as used here+ Thus the rate of transfer to fetal blood fro$ $aternal blood "astaken to be /+4 ti$es that in the !a $odelF the rate of return to $aternal blood "asnot altered+ Utake rates for Sr fro$ fetal blood to bone surfaces and soft tissues

"ere those derived for !a+ 9ll other rates bet"een fetal co$art$ents "ere thoseused for Sr in !DP $odels for children+Detention of !a and Sr in the lacenta andtheir resence in a$niotic ]uid "ere not considered+ 9lthough li$ited data are


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Table 136 ntakes of !a either rior to concetion or during regnanc*


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!o$$itted doses to red bone $arro" in offsring "ere esti$ated to be greaterthan corresonding doses in adults b* factors of about nine for 3!a and about t"o

for ./Sr+ The distributions of !a and Sr bet"een fetus and $other redicted b* the$odel are generall* consistent "ith available ani$al data+ Thus% the t"o ele$entssho" si$ilar atterns of increasing transfer later in regnanc*+or e8a$le% for igs given 3!a at ti$es during the \rst% second or thirdtri$ester% fetal retention $easured : da*s later accounted for /+.=% 4= and 21= oftotal retention% resectivel*+ ,irect co$arisons of lacental transfer and fetalretention of !a and Sr in rats and $ice sho"ed discri$ination against Sr asdiscussed above+ or both ele$ents% retention b* the fetus after ad$inistration latein regnanc*% in all ani$al secies studied% corresonded to concentrations greaterthan in the $other+ or e8a$le% !6!# ratios of 3; can be esti$ated for igsand shee in the third tri$ester after ad$inistration : da*s reviousl*+ 5alues ofA; "ere reorted for Sr in rats and guinea igs at birth after ad$inistration 1;3da*s reviousl* in the rat and 2 "eeks reviousl* in the guinea ig+ Tolst*kh et al

reort $easure$ents of concentrations of ./Sr in 4 stillborn hu$an fetuses andtheir$others for "ho$ the eriod of $a8i$u$ conta$ination due to consu$tionof Techa river "ater occurred at different ti$es before regnanc*+ The skeletalconcentration (0C+g1 !a) ratios% fetus6$other% "ere /+/1;/+/A "hen intakes of./Sr "ere largel* during childhood (1 *) and /+1.;/+23 "hen $a8i$u$ intakes"ere during adulthood (2 *)+ !orresonding concentration ratios redicted b* the$odel "ere /+/:;/+/< for intakes during childhood and /+11;/+13 for intakes

during adulthood+ n co$aring observed and redicted ratios% it should be notedthat for the earl* intake grou studied b* Tolst*kh et al% intrauterine death of t"oof the fetuses occurred bet"een 4;< $onths after concetion and the third fetus


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$..T>E &T)


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Table14

9ll the sa$les "ere cleaned of fascia and $uscle% died in /+1 H!l%"ashed "ith distilled "ater% and ashed in a $uffle furnace for 12 hours at4//+ The "hite residue "as then ground to ass a 13/ $esh sieve and a

ortion "as $i8ed "ith secial sectroscoic grahite o"der and!uS/3^HE>% the internal standard $aterial% in the ratio of 1 art bone ash%2 arts grahite% and . arts !uS/3+HE/+ 9bout < $g+ of the $i8ture "erelaced in a latfor$ t*e electrode cut fro$ _ inch secial sectroscoic


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the !uS/3^HE>% and H!l "ere each e8a$ined for residual strontiu$ andin no case "as an* of this ele$ent detected under the conditions used in

this "ork+ The sectrograhic anal*sis of the !a!>a b* the addition $ethodsho"ed that it contained about /+//3 er cent strontiu$+ This "as taken intoconsideration in the standard sa$les "hen the !a!/A "as an addedconstituent+ Seven to ten deter$inations on each of si8 standard sa$lessho"ed that the standard deviation of the average of three deter$inations"as 1/ ercent of the a$ount resent for the range of strontiu$concentrations found in the sa$les e8a$ined in the resent "ork+ (To obtain

such accurac* all unkno"ns "ere anal*Eed in trilicate+)


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a$ounts of Sr are ingested+ 9lthough the foods consu$ed b* hu$ans duringthe 3/ to / *ears rior to 1.13 robabl* differed fro$ "hat "e toda*

"ould call an average diet% such differences are not reflected b* the Srcontent in the bones of the 1.13 individuals co$ared to the 1.3. series+9ttention is dra"n to the high Sr values for the bones of a $onth-oldh*drocehalic child (Table 14% Subect 4)+ Ho"ever% seculations as to

ossible correlation of the h*siological disorder and the see$ingl* abnor$allevel of bone strontiu$ are hardl* ustifiable on such $eager data+ ithinan* given individual% there aear to be no gross differences in the a$ount

of Sr deosition in the various bone tissues studied+ n contrast% Pecher hassho"n that the vertebrae of $ice inected intravenousl* "ith SrSg salts are$ore radioactive than other bon* structures% indicating $ore raid deositionin vertebral calcified tissue+ t $a* "ell be that "ith the assage of ti$e thenor$al d*na$ics of bone salt for$ation and dissolution bring about a $oreeven distribution of such $aterials throughout the skeletal s*ste$+ 9lthough

the observations sho" so$e Sr resent in all the bones e8a$ined% this isnot evidence that Sr is an essential co$onent of bone+1+ Sectrograhic anal*ses for strontiu$ "ere $ade on sa$les of arietal%vertebral% rib% and fe$ur bone ash fro$ t"ent*-si8 individuals var*ing in agefro$ fetus to : *ears+ n addition% si$ilar anal*ses "ere erfor$ed on

arietal% rib% and fe$ur sa$les obtained fro$ t"elve cadavers% all of "hichhad been in a state of reservation since 1.13+

2+ The Sr content of all fetal seci$ens la* in the range of /+/1 to /+/1.er cent (average% /+/14 er cent)+ The range for all other seci$ens% saveone% "as /+/14 to /+/33 er cent (average% /+/23 er cent)+


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10'%M()*+EME,TS %, TE %*%,ET%/ M*EL "*) ST)*,T%$M

%T ALL*A,/E "*) A2E A, 2E,E) %""E)E,/ES %, *,E

M%,E)AL META*L%SM

The develo$ent of $athe$atical $odels used to describe retention of internall*incororated radionuclides is $ainl* based on available $easure$ents ofradioactive isotoes in the hu$an bod*+ 9 uniCue data- base on ./Sr in hu$ans"as co$iled at the Urals Desearch !enter for Dadiation #edicine (UD!D#) as aresult of long-ter$ dosi$etric studies of Techa Diver residents e8ternall* andinternall* e8osed to signi\cant releases of liCuid radioactive "astes fro$ the#a*ak Production 9ssociation (#P9) into the Techa Diver in the earl* 1./s+ Thedatabase includes $easure$ents of radionuclide content in bones% teeth and in vivo"holebod* $easure$ents in a seciall* designed "hole-bod* counter (0!)conducted for $ore than 1%/// ersons over a 3 * eriod+ These data can serveas a useful tool for the stud* of features of strontiu$ $etabolis$ in hu$ans and

also for biokinetic $odelling+ ,ata on ./Sr "hole-bod* counts obtained for theTecha Diver residents in 1.:3;1.:4 "ere e$lo*ed to derive an age-deendentretention function of strontiu$ in bone+ n contrast to si$le retention functions forseci\c organs used in the ast% biokinetic $odels have no" been created todescribe the distribution of internall* incororated radionuclides in the hu$an

bod*+ 9n age-deendent biokinetic $odel for strontiu$ is given in the udated!DP Publication 4:+ Ho"ever% calculations of ./Sr bod* burdens $ade for the

Techa Diver residents using the !DP 4: $odel have been sho"n to beinconsistent "ith the results of ./Sr bod* burden 0! $easure$ents+ !DP 4:$odel results are sho"n to both over-redict and under-redict actual 0!


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1/.1.+S)I"()I4 4 "45+7 ;(("+)+S

The Techa biokinetic $odel (T0#) is a reresentation of the !DP biokinetic

$odel for strontiu$ and the !DP $odel for the gastrointestinal tract (GT) asingestion "as the $ain ath of strontiu$ intake for the Techa Diver oulation+Para$eters of the Techa biokinetic $odel "ere seci\call* evaluated for the TechaDiver oulation because calciu$ and strontiu$ $etabolis$ is in]uenced b*features of ubertal $aturation and ageing characteristics of the oulation studied+The $ost i$ortant ara$eters describing the behaviour of bone-seeking ele$entsin the skeleton are considered to be the follo"ing6 (1) age- and gender-deendent

calciu$ content of the skeleton% the calciu$ accretion rate during childhood andadolescence% and calciu$ loss in ageing ersonsF and (2) trabecular and cortical

bone re$odelling rates% deter$ining strontiu$ eli$ination+ t should be noted thatara$eters describing $ove$ent of a substance through the GT "ere not changede8cet the one describing gut utake fraction (f1 factor)+ The reli$inar* valuesfor these $aor $odel ara$eters "ere derived fro$ ublished data on calciu$

and strontiu$ $etabolis$ and fro$ studies of the Techa Diver oulation+ Table1< rovides a descrition of the $aor data sets used to derive values for seci\cT0# $odel ara$eters+ T0# $odel ara$eters "ere esti$ated b* \tting to the$aor data sets on ./Sr in hu$ans% including (1) 0! $easure$ents of ./Sr

bod* burdens for residents of #usl*u$ovo (a village located on the Techa Diver)esti$ated A/ and 3 * after the intake occurred and (2) radioche$ical$easure$ents of ./Sr concentration in bones conducted in 1.43 in the UK and the

US9 fro$ studies of global fallout9s a result%a universal set of ara$eters for$ales and fe$ales of all ages fro$ birth to


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ad$inistration (corrected for individual value of gut absortion) to a ho$ogeneousgrou of $ales+ The range of ages for the subects investigated "as 2/;A/ *% "ith

$ost ersons aged 21;22 *+ igure 12 sho"s good agree$ent bet"een thecalculated and $easured valuesThis art describes the develo$ent of an i$roved biokinetic $odel for strontiu$accounting for age and gender differences in strontiu$ $etabolis$+ The uniCuedata set of ./Sr bod* burdens for Techa Diver residents% data on global ./Sr inhu$an bones obtained in the UK and the US9% data on "hole-bod* $ineralcontent and data on bioche$ical $arkers of bone $etabolis$ "ere used to derive

the ara$eters for the T0#+ The T0# "as validated using different sets of dataon strontiu$ retention in hu$ans and "as sho"n to satisfactoril* describestrontiu$ retention for different kinds of intake+9lthough the T0# "as develoedfor the Techa Diver oulation% this $odel can be used to describe strontiu$retention in other oulations characterised b* si$ilar features of ubertal$aturation and ageing+ 9lso% the aroaches to derivation of age- and gender-

deendent $odel ara$eters develoed in this stud* can be used in $odel \tting todata on other oulations+ 9 detailed descrition of the T0# $odel develo$entand tabulated values of $odel ara$eters for $ales and fe$ales of %++ ages is

rovided in Shagina et al


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Table 1


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igure 126 !o$arison of !DP 4: and Techa biokinetic $odel (T0#) $odel redictions "ith e8eri$ental data on


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11+1+0iokinetic data for carbon (taken fro$ Publication 4)

>rganic carbon

,istribution(=)

0iological half-ti$e(da*s)

9ge 0od* tissue 0od* tissue

A$onths

1// TH !DPQS ,>S !>!TS >D

##0DS > TH PU0'!+ 1+ S>UD!S > U!DT9T TH

0>KT! #>,'S

3) ell T+P+ et al 9 #>,' >D TH TD9SD > !9'!U# 9, STD>TU#

T> TH TUS

) + 0+ Shagina#PD>5#TS TH 0>KT! #>,' >D STD>TU#

TH 9''>9! >D 9G 9, G,D ,D!S 0>

#D9' #T90>'S#

4) !DP@Publication@1/A-9nnals@of@the@!DP@A:(2-3)-ree@e8tract

:) Wa$es@#artin@radiation rotection


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Appendix: 1Age-specific transfer rates (inverse days) for strontium (taken from Publication 67)

Age

3 months 1 year 5 years 10 years 15 years Adult

ST0 to plasma 8.33E-01 1.83 2.00 1.47 8.67E-01 2.50

ST1 to plasma 1.16E-01 1.16E-01 1.16E-01 1.16E-01 1.16E-01 1.16E-01

ST2 to plasma 3.80E-04 3.80E-04 3.80E-04 3.80E-04 3.80E-04 3.80E-04

one sur!a"e to plasma 6.01E-01 6.01E-01 6.01E-01 6.01E-01 6.01E-01 5.78E-01

#one$"h% "ort&"al 'olume to plasma 8.22E-03 2.88E-03 1.53E-03 (.04E-04 5.21E-04 8.21E-05

#one$"h tra)e"ular 'olume to plasma 8.22E-03 2.88E-03 1.81E-03 1.32E-03 (.5(E-04 4.(3E-04

*lasma to ST0 2.50 5.50 6.00 4.40 2.60 7.50

*lasma to ST1 5.00E-01 1.10 1.20 8.80E-01 5.20E-01 1.50

*lasma to ST2 1.00E-03 2.20E-03 2.40E-03 1.80E-03 1.00E-03 3.00E-03

*lasma to "ort&"al )one sur!a"e (.00 5.40 4.67 6.28 8.00 1.67

E$"h% )one 'olume to )one sur!a"e 4.30E-03 4.30E-03 4.30E-03 4.30E-03 4.30E-03 4.30E-03

one sur!a"e to e$"h )one 'olume (.24E-02 (.24E-02 (.24E-02 (.24E-02 (.24E-02 1.16E-01

E$"h )one 'olume to none$"h 'olume 4.30E-03 4.30E-03 4.30E-03 4.30E-03 4.30E-03 4.30E-03

*lasma to tra)e"ular )one sur!a"e 2.25 1.35 1.33 2.12 3.10 2.08

*lasma to ur&nary )ladder "ontents 5.77E-01 1.27 1.38 1.02 6.00E-01 1.73

*lasma to +, 1.75E-01 3.85E-01 4.20E-01 3.08E-01 1.82E-01 5.25E-01

% e$"h e$"hangea)le/ none$"h none$"hangea)le

internal dosimetry of pure beta emitters other than tritium

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