Appendix 1. Post - Chernobyl Thyroid Cancer in Ukraine

Transcription

1 Appendix 1 Post - Chenobyl Thyoid Cance in Ukaine

2 POST- CHERNOBYL THYROID CANCER IN UKRAINE. REPORT 1: Estimation of thyoid doses. 1 I. Likhtaov, 1 L. Kovgan, 1 S. Vavilov, 1 M. Chepuny, 2 A. Bouville, 2 N. Luckyanov, 3 P. Jacob, 4 P. Voillequé, 5 G. Voigt 1 Radiation Potection Institute ATS Ukaine,Melnikova 53, Kiev, Ukaine 2 DHHS, NIH, National Cance Institute, Division of Cance Epidemiology and Genetics, 6120 Executive Blvd., Bethesda, MD , USA 3 GSF-National Reseach Cente of Envionment and Health, Gemany 4 MJP Risk Assessment, Inc East Bayaud Avenue, Denve, Coloado 80230, USA 5 IAEA, P.O. Box 100, Wagame Stasse 5, A-1400 Vienna, Austia A1-1

3 Abstact. About 1.8 EBq of 131 I was eleased into the atmosphee duing the Chenobyl accident that occued in Ukaine on 26 Apil Moe than 10% of this activity was deposited on the teitoy of Ukaine. Beginning 4-5 yeas afte the accident, an unusually high incidence of thyoid cance among childen, believed to be caused in pat to exposue to 131 I, has been obseved in the most contaminated egions of Ukaine. A detailed estimation of the thyoid doses fom 131 I fo the Ukainian population has been caied out in the famewok of lage scale epidemiologic studies of childhood thyoid cance. Individual thyoid doses have been estimated fo the membes of a cohot study in the most contaminated aeas, while goup doses, boken down accoding to age, gende, and location of esidence at the time of the accident, have been estimated fo the entie county. Results aveaged ove lage population goups indicate that the entie teitoy of Ukaine can be subdivided into thee zones: (1) a zone of high thyoid doses (above 35 mgy) in Zhytomy, Kyiv, Rivne, Chenihiv, and Chekasy oblasts; (2) a zone of modeate thyoid doses (14-35 mgy) in Volyn, Vinnytsia, Khmel nyts k, Chenivsi, Kiovohad, Poltava, Sumy oblasts, Kyiv-city and the Autonomous Republic of Cimea; and (3) a zone of low thyoid doses (13 mgy and less) in the othe 12 oblasts of Ukaine and the city of Sevastopol. Data, models, and pocedues equied fo the estimation of individual doses and of goup doses ae descibed in the pape. An analysis of the distibution with time and location of the thyoid cance mobidity fo the esidents of Ukaine who wee aged 1 to 18 at the time of the accident also will be submitted fo publication in the nea futue. A1-2

4 Intoduction About 1.8 EBq of 131 I was eleased to the atmosphee duing the Chenobyl accident that occued in Ukaine on 26 Apil 1986 [1]. It is estimated that appoximately 11% of this activity was deposited on the teitoy of Ukaine [2, 3]. The consumption of fesh milk contaminated with 131 I was the main souce of thyoid iadiation fo pesons in contaminated aeas. Beginning 4-5 yeas afte the accident, an unusually high incidence of thyoid cance among childen and adolescents exposed to 131 I was obseved in the contaminated egions of Ukaine [4-10], Belaus [1,11-15], and Russia [16-18]. Othe adioactive isotopes of iodine (notably, 132 I, 133 I, and 135 I) and pecuso adionuclides ( 131m Te and 132 Te) wee also eleased and could contibute to the thyoid dose. Evaluations indicate that the thyoid doses poduced by these adionuclides wee a elatively small faction of the total thyoid dose fo most people [19, 20]. This pape is theefoe focused on the dose fom 131 I. The investigation of the high incidence of thyoid cance among populations that wee exposed to adioiodine afte the Chenobyl accident consists of two components: - Retospective assessment of the thyoid dose fo individuals and fo goups of people aggegated accoding to age, gende, and esidence fom the time of the accident until the end of June 1986; and - Assessment of the isk of thyoid cance caused by the thyoid s exposue to adiation. This assessment can be made in the famewok of thee types of epidemiologic study: cohot [21, 22], case-contol [12], and ecological [4, 23]. The pesent publication is devoted to a detailed estimation of the thyoid doses fom 131 I fo the Ukainian population, and suppots an associated ecological analysis of the obseved thyoid cance mobidity. The estimation of thyoid doses esulting fom the Chenobyl accident was initiated in May-June 1986 [24]. This estimation was based on the 131 I activities measued A1-3

5 in the thyoids of people. A vey simple model, which assumed a single intake of 131 I at the time of the accident, was used to deive the thyoid dose fom the measuement of thyoidal content. Although these estimates wee athe consevative, they helped to define egions with the highest thyoid doses. It was expected that populations of those egions would have the highest isk of developing adiation-induced thyoid cances. Since 1986, thee have been many evisions of the initial dose assessments with the aim of impoving thei ealism and eliability. Diffeent methodologies have been developed o impoved fo the estimation of the thyoid doses eceived by people whose thyoid adioactivity content was measued in May-June 1986 as well as those eceived by people without such measuements [15, 25-29]. This eseach was stimulated by seveal lage scale epidemiologic pojects that suveyed childhood thyoid cance in Ukaine [22, 30]. These pojects wee initiated cica Detailed ecological models of adioiodine tansfe along food chains [31] and special mesoscale models of atmospheic tansfe of adionuclides [2,3] wee developed and used at that time. Results of lage-scale inteviewing wee used to obtain infomation on the esidential histoy and dietay habits of the suveyed cohot membes. In the cuent thyoid dosimety system, thee ae thee levels of dosimety suppot fo diffeent types of epidemiological eseach. The fist level (individual thyoid doses fo cohot membes) is used in a classical cohot study [31]. The second and the thid levels ae used in ecological studies to estimate goup doses fo settlements, aions 1, o oblasts, taking into account the gende and age of the inhabitants. Data, models, and pocedues equied fo the estimation of individual doses (fist level) and of goup doses (second and thid levels) ae descibed in this pape. Dose estimates ae pesented fo people who wee aged 1 to 18 and who lived in any pat of Ukaine at the time of the accident. Infants who 1 Raion is an administative unit within an oblast. Usually thee ae 10 to 20 aions in an oblast. The aion is compaable to a county in the United Stattes, while the oblast is compaable to a state. A1-4

6 wee less than one yea old at the time of the accident ae not consideed in this pape. Although thee wee many measuements of thyoid activity pefomed in May-June 1986, few of these wee fo vey young childen. An analysis of the distibution with time and location of the thyoid cance mobidity fo the esidents of Ukaine who wee aged 1 to 18 at the time of the accident will be.submitted fo publication in the nea futue. The esults of that analysis will consist of an assessment of the age-dependent changes in the backgound thyoid cance mobidity fo the Ukainian population, and an assessment of the absolute and elative isks of the adiation-induced thyoid cance. Geneal equations. Mateials and methods The vaiation with time of the 131 I activity in the thyoid Q a, s ( t) (Bq) fo a subject of age a and gende s is defined by two main pocesses: (1) uptake of 131 I by the thyoid, which is descibed by a function ( ) (Bq. d -1 ) and (2) excetion of 131 I fom the U a, s t thyoid, which is assumed to be exponential. It is chaacteized by the effective constant of elimination of 131 I fom the thyoid, λ ef a (d -1 ), which is the sum of the biological biol a elimination constant, λ (d -1 ), and of the adioactive decay constant of 131 I, λ I, (d -1 ). Theefoe, the function Q a, s ( t) can be descibed as t ef λ Q ( t) = U t e a a s ( ), a, s 0 ( t τ ) dτ, (1) The absobed thyoid dose, D, (Gy), eceived until time Т afte the accident, is th a s α T α D ( T ) = Q dt A ( T ) a, s =, (2) a, s a, s M 0 M a a A1-5

7 whee α is enegy absobed in the thyoid due to the adioactive decay of a unit activity of 131 I duing one day (J/Bq. d); M a is the age-dependent thyoid mass, (kg), aveaged fo boys and gils; A a, s ( T ) is the time-integated activity of the 131 I content in the thyoid (duing the time peiod fom 0 to T) fo a subject of age-gende goup a-s (Bq d). Ecological model. Vaiation with time of the 131 I activity in the thyoid, Q a, s ( t) in eq. (1), can be estimated based on an ecological model that descibes the tanspot of 131 I though the envionment and in people. The model takes into account inhalation of contaminated ai, the pocesses of 131 I deposition on gound and vegetation, tansfe of 131 I into milk, consumption of contaminated foods by humans, and uptake and etention of 131 I in the thyoid. The output of the model is dynamics of 131 I activity in the thyoid duing the peiod of exposue. Most of the 131 I elease fom the Chenobyl eacto occued duing the fist few days afte 26 Apil 1986 and adioactive decay limited the peiod of concen about intakes of 131 I in the diet to about two months. Fundamental to the model ae measuements and estimates of the adionuclide depositions in locations of inteest afte the accident. The total depositions of 137 Cs have been measued in settlements thoughout Ukaine. The daily depositions of both 137 Cs and 131 I have been estimated using a mesoscale atmospheic tanspot model. A map of cumulative 131 I deposition on the teitoy of Ukaine is shown on Figue 1 [2,3]. Thee pathways of 131 I intake wee consideed in the ecological model: inhalation, ingestion of leafy vegetables and milk. The mathematical desciption of the model, as well as paamete values, ae given in Annex 1 Diect measuements of 131 I activity in the thyoid. Diect measuements of adioactivity in the thyoids of the inhabitants of affected teitoies wee pefomed between 20 and 40 days afte the accident. The esults of the A1-6

8 diect measuements on the subjects (indexed by k) ~ Q k, a, s (Bq), wee used to estimate the thyoid doses eceived by the individuals whose thyoid activities wee measued. The methodology of thyoid measuements used in Ukaine in Apil-June of 1986 (goups of population, teitoial distibution of the measuements, and desciptions of the measuing devices and thei calibation) has been pesented in detail in pevious publications [26-29]. The esults of the thyoid measuements wee coected to take into account the pesence of adiocesium in the human body. Values of the coection factos fo diffeent ages and diffeent times of measuements ae descibed in a sepaate publication. Thyoid dose estimation Definitions and pinciples The thyoid dose, D a, s ( T ) (Gy), estimated with help of function, Q a, s ( t) (Bq), fo a subject of age a and gende s who was in a settlement with a specified level of 131 I deposition is called the ecological thyoid dose. Thyoid dose, calculated taking into account esult of thyoid activity measuement ~ Q k, a, s (Bq) is called the instumentally individualized thyoid dose and denoted as D k, a, s ( T ) (Gy). The instumentally individualized thyoid dose based on infomation on the individual s diet and behavio is called the questionnaie-based instumentally individualized thyoid dose. The questionnaie-based instumentally individualized thyoid doses ae the most eliable estimates of thyoid doses eceived by individuals. Based on esult of the diect thyoid activity measuement ~ Q k, a, s (Bq), the individual scaling facto fo k-individual of age a and gende s, scale K k, can be estimated as: Q ~ scal k, a, s K k =, whee Q a, s ( tmeas ) is estimation of the thyoid activity at the time of Q ( t ) a, s meas A1-7

9 measuement, t meas based on ecological model. It is assumed that the dynamics of 131 I activity in the thyoid of individual k is linealy elated to the function ( ). The Q a, s t instumentally individualized thyoid dose D k, a, s ( T ) can theefoe be calculated as: D k, a, s ( T ) = scale K k D a, s ( T ) (3) Individual doses D k, a, s ( T ) ae used fo the estimation of the settlement-specific thyoid doses fo diffeent age-gende goups and (2) fo estimation of age-gende thyoid doses aggegated ove the settlement in a aion o oblast. Thee ae thee levels of thyoid dose estimation. Fist level of thyoid dose estimation The fist level of thyoid dose estimation is used fo the individuals with diect thyoid measuements; it also takes into account esults of the individual inteviews on diet and behavio (the questionnaie-based instumentally individualized thyoid dose) o efeence diet and behavio estimated fom othe souces (the instumentallyindividualized thyoid dose). Fo the majoity of the appoximately 130,000 Ukainians whose thyoid activities wee measued in 1986 instumentally individualized thyoid doses could be estimated. Results of inteviews of ual and uban inhabitants of Chenihiv oblast (9,500), Kyiv oblast (3,000) and Zhytomy oblast (2,300) on dietay habits and food consumption ates in May-June 1986 wee used fo the development of efeence age-gende dependent consumption ates (Table A1.2). This suvey was undetaken in as pat of the Thyoid Passpotisation of the affected Ukainian population and was funded by the Ministy of Chenobyl and Emegency Situation of Ukaine [32, 33]. The questionnaies wee developed by the Scientific Cente on Radiation Medicine of Ukaine, which managed the poject. A1-8

10 Soon afte the accident the inhabitants of the settlements of the zones neaest to the Chenobyl NPP wee evacuated to othe settlements located in Kyiv, Chenihiv, and Zhytomy oblasts. The thyoid doses of people who wee evacuated wee caused patly by the thyoid exposue at the place of evacuation and patly by the thyoid exposue at the place to which they wee elocated. Thyoid activity measuements wee pefomed fo ~9,500 inhabitants of 53 evacuated settlements. The infomation on the settlement of evacuation and on the settlement of elocation was taken fom the ecods of measuements, and then used in the calculation of the instumentally individualised thyoid doses fo the evacuees. Individual inteviews fo moe than 13,000 subjects who wee less than 18 yeas old at the time of the accident (o of paents of the subjects who wee less than 10-yea old) egading diet and post-accident elocations have been pefomed in the Ukaine- Ameican cohot thyoid study [21,22,31]. Diect measuements of thyoid activity wee pefomed fo all subjects of the cohot. Second level of thyoid dose estimation The settlement-specific doses in locations whee the diect thyoid measuements wee pefomed in May-June 1986 ae consideed in the second level of thyoid dosimety. The measuements wee made fo the inhabitants of 787 settlements of Kyiv, Chenihiv, and Zhytomy oblasts, whee contamination levels wee the highest. This numbe includes 53 settelements fom which people wee evacuated. In each of these 787 settlements, thee wee pesons whose thyoid activities wee not measued, and a method fo estimation of thyoid doses fo those people is needed. The pocedue is based on the elative timeintegated activities of 131 I in thyoids of diffeent age and gende goups. The elationships fo individuals whose thyoid activities wee measued ae used to estimate time-integated thyoid activities fo 36 age and gende goups (both males and females fo yealy age intevals fom 1 to 18) and then doses to the same goups in the settlements. A1-9

11 The lagest numbe of thyoid activity measuements was made fo childen of ages 12 to 14 (Figue 2). This age inteval, denoted by a ef, is called the efeence ageinteval. Thee wee 619 settlements whee thyoid measuements wee pefomed on childen in the efeence age-inteval. In addition, measuements in the efeence ageinteval wee pefomed in 49 settlements that wee evacuated soon afte the accident. The total numbe of measuements (ages 1 to 18) in these categoies wee ~74,000 and 8,000, espectively. Thyoid measuements in Ukaine in 1986 wee made with eight types of instuments. Results obtained using devices with gamma spectometic capability ae moe eliable than those obtained fom less sophisticated counting devices. Fo gamma spectometic measuements, a minimum of fou measuements pe settlement wee equied fo inclusion in the analysis. Fo non-spectometic instuments (e.g., SRP-68-01), only settlements with ten o moe measuements wee included in the analysis. The numbe of settlements and individual measuements fo which these citeia wee satisfied ae given in Table 1. Fo evey peson k of age a and gende s with a diect measuement in settlement j, the instumentally individualized time-integated activity of 131 I in the thyoid is denoted as: Ak, a, s, j (Bq d) and the elative time-integated 131 I activity in the thyoid, f a, s, j k, is defined as: f = k, a,s, j A Aˆ k,a, s, j aef,s, j whee Aˆ is the geometic mean of the time-integated a ef, s, j 131 I activity in the thyoids of membes of the same gende of the settlment j in the efeence age inteval: When we conside all togethe the settlements with diect thyoid measuements in the efeence age inteval, the geometic mean values f a,s (weighted ove the numbe of membes in the efeence age-goup of the settlement) fo each of 36 age-gende goups A1-10

12 wee calculated using the values f. Statistical compaisons of values of f k, a, s, j a,s fo diffeent subpopulations and diffeent locations wee made with the Mann-Whitney test [16,42]. Thee ae statistical diffeences between samples of ual and uban childen fo the majoity of age goups. Thee ae also diffeences between the entie samples of boys and gils fo almost all ages. In the thyoid dosimety of the second level, six tabulated functions f a,s have been used fo the age-gende aveage settlement specific thyoid dose estimations: two functions fo ual aeas, two functions fo uban aeas and two functions fo the evacuated population. In each case the functions wee diffeent fo males and fo females. The computed geometic mean values of f a,s and the associated geometic standad deviations (GSDs) fo diffeent age and gende goups ae given in Table 2. The tabulated values wee used to estimate time-integated thyoidal 131 I activities ~ A a, s, j fo each age-gende goup in evey settlement j whee diect thyoid measuements wee pefomed in 1986: ~ A a, s, j ~ = A f (4) a, s, j a, s ef whee ~ A, s, j a ef is the settlement-specific time-integated thyoidal 131 I activity fo gende s in the efeence age inteval of the settlement j. and of the time-integated thyoidal 131 I activity ~ A, s, j a ef A k a, s, j is deived fom the values of f a,s, fo the pesons of gende s fo which the diect measuements wee pefomed in the settlement j. The median thyoid doses D ~ a, s, j fo each of 36 age-gende goups in settlement j (whee diect measuements of childen wee pefomed) ae calculated as: A1-11

13 ~ D a, s, j = α M a ~ A a ef, s, j f a, s (5) Statistical popeties of the fist and second levels of thyoid dose estimations Analysis of distibutions of the measued thyoid activities, instumentally-individualized time-integated thyoid activities, A k a, s, j ~ ( Q k, a, s, j ) t and of the,, fo diffeent agegende goups in the same settlement, showed that accoding to Lilliiefots test [43], (70-100% fo diffeent age-gende goups) these distibutions ae lognomal fo most settlements. Compaison of aithmetic and geometic means fo the samples of measued thyoid activities, ~ ( Q k, a, s, j ) t, made on the same day t fo childen of the same age and gende in the same settlement j showed that this atio is athe stable fo all samples. It anges fom 1.35 to Ratios between aithmetic and geometic means fo instumentally-individualized time-integated thyoid activities A k a, s, j, fo people of the same gende, age, and settlement j aveaged ove all settlements anged fom 1.28 to 1.61 fo all age-gende goups. Compaison of esults obtained in the fist and second levels of thyoid dose estimation shows that fo all age-gende goups geometic means of the instumentallyindividualized time-integated thyoid activities A k a, s, j, ae vey close to the calculated values of ~ A a, s, j : the atios aveaged ove all age goups ae 1.06 and 1.08 fo boys and gils with standad deviation of about The atios of the aithmetic means of A k, a, s, j to ~ A a, s, j in the same sets ae substantially geate, with values aveaged ove all age goups of with standad deviation of Theefoe, goup assessments of the thyoid doses of the second level, ~ D a, s, j, obtained fo age-gende goup a-s of any settlement j, ae close to the geometic means of A1-12

14 the instumentally-individualized doses obtained fo the same age gende goup fom the same settlement. Assuming that distibutions of the estimated thyoid doses of the second level ae lognomal, the coesponding aithmetic means of those distibutions can easily be deived fom the geometic means and geometic standad deviations [44]. The thid level of thyoid dose estimation The thid level of thyoid dose estimation povides oblast-specific thyoid dose estimates fo the 36 age-gende goups. The pocedue of the oblast-level thyoid dose aggegation includes dose estimates fo settlements with and without diect thyoid measuements. The fist subsection deals with the thee oblasts whee thyoid measuements wee made in some settlements. Then the pocedue of dose estimation fo oblasts without thyoid activity measuements is pesented. Diect measuements of thyoid activity wee pefomed on childen, adolescents (aged 18 y) and adults in the 787 settlements of Kyiv, Zhytomy and Chenihiv oblasts (including Kyiv, Zhytomy and Chenihiv cities). The thyoid doses fo 36 age-gende goups in 748 of these 787 settlements wee estimated using the second level of thyoid dose estimation. Although many diect thyoid measuements wee pefomed in Kyiv, Zhytomy and Chenihiv oblasts, thee ae aions in these oblasts whee no measuements wee made The settlements in these oblasts (and in geneal in the whole teitoy of Ukaine) can be subdivided into thee goups: - Goup 1 includes settlements whee diect measuements wee pefomed in 1986; the second level of thyoid dose estimation was used fo the inhabitants of these settlements. Index j was used fo the identification of the settlements of goup 1. - Goup 2 includes settlements whee no diect thyoid measuements wee made, but that ae located in aions whee measuements wee made in othe A1-13

15 settlements. Index j * will be used fo the identification of the settlements of goup 2. - Goup 3 includes settlements that ae located in aions, o oblasts, whee no diect thyoid measuements wee made. Index j ** will be used fo the identification of the settlements of goup 3. Most of the settlements in Ukaine fall into Goup 3. Thyoid dose estimation fo the settlements of Goup 2. The estimation of the aveage time-integated thyoidal 131 I activities A a, s, j* (Bq d) fo settlements of Goup 2 ae based on dose estimates deived fom diect thyoid measuements in settlements in the same aion as the settlement of inteest. This was done using a aion scaling facto K scal s, aion which is the aveage value of the scaling factos fo the settlements j of Goup 1 K scal s, j. Scaling facto K scal s, j wee defined as atio of the time-integated thyoidal 131 ecol I activity estimated using the ecological model A, (Bq d), to the time-integated, thyoidal 131 I activity ~ A aef s, j a ef s, j, estimated based on esults of diect thyoid measuements using the function f a,s.values of K scal s, aion estimated fo each gende in 14 diffeent aions of Kyiv, Zhytomy, and Chenihiv oblasts ae given in Table 3. Total numbe of settlements in each aion and numbe of settlements that wee used fo the development of the scaling factos K scal s, aion also ae given in Table 3. The thyoid doses fo the 36 age-gende goups in the settlements j * of Goup 2, whee diect thyoid measuements wee not pefomed in 1986, D a, s, j*,ae estimated as: D a, s, j* A ecol a,s,j* ef = α f a, s (6) M a K scal s, aion A1-14

16 Thyoid dose estimation fo the settlements of Goup 3. Diect thyoid measuements wee not pefomed in 21 oblasts of Ukaine and the Republic of Cimea. These aeas include 25,803 settlements with about 12 million people aged 1-18 yeas old. All these settlements as well as the settlements of Kyiv, Zhytomy, and Chenihiv oblasts located in the aions whee thee wee no diect measuements belong to the settlements of Goup 3. Table 3 shows that thee ae athe substantial diffeences between the timeintegated thyoid 131 I activities fo the efeence age inteval calculated with the ecological model ( A ecol ) and those based upon thyoid measuements ( ~ a ef,s, j A,s, j ). A numbe of easons may cause such diffeences, including inaccuacies in the estimates of 131 I deposition densities, in the paametes of the ecological model and oveestimation of a ef consumption ates of milk and leafy vegetable due to pesonal o paental estiction. It is assumed that pesonal o paental estiction of dietay intake was coelated with the level of local deposition of adioactivity. Infomation on 137 Cs deposition was used in this analysis as these data ae easily available. The time-integated thyoidal 131 I activities A a,s,j** fo the settlements j ** wee calculated using the scaling facto K scal s, j * * detemined as: K scal s, j * * =B σ β Cs, j. Fo the estimation of the paametes B and β the coelation between values of scaling factos K scal s, j fo all settlements j of Goup 1 in Kyiv, Chenihiv and Zhytomy oblasts, and the measued cumulative density of 137 Cs deposition σ Cs, j (kbq m -2 ) fo these settlements was analyzed. Paametes B and β used K scal s, j * * estimated, by fitting, fo ual and uban boys and gils, ae given in Table 4. Fo the settlements with A1-15

17 low levels of 137 Cs deposition, σ β Cs, j, the calculated value K scal s, j * * was found to be lowe than 1 and, a value K scal s, j * * =1 fo these settlements was assumed. Thus the thyoid doses fo each of 36 age-gende goups in the settlements of Goup 3, D a, s, j**, is: D a, s, j** A ecol a,s,j* ef = α fa s M K scal, (7) a s, j ** Oblast-specific thyoid doses fo diffeent age-gende goups of Kyiv, Zhytomy and Chenihiv oblasts wee estimated as sum of population weighed doses aveaged ove the settlements of Goup 1 ( D ~ a, s, j ), Goup 2 ( D ) and goup 3 ( D a, s, j* a, s, j** ) 2. In the oblasts with no diect thyoid measuements in 1986 all settlements belong to Goup 3. Theefo the oblast-specific thyoid doses fo evey age gende goup in these oblasts wee estimated as the population weighted doses D aveaged ove all settlements of the a, s, j** oblasts. Main esults and discussion Fist level of thyoid dosimety: instumentally individualized thyoid doses About 130,000 instumentally individualized thyoid doses wee econstucted fo Ukainian people whose thyoid activities wee measued in These measuements wee made in Kyiv, Zhytomy, and Chenihiv oblasts, which wee the most contaminated afte the Chenobyl accident. The estimated instumentally individualized doses fo diffeent age and gende goups in Kyiv, Zhytomy, and Chenihiv oblasts ae given in Table 5. The doses ae given sepaately fo ual and uban populations, as well as fo 2 This is an appoximation as the sum of medians is not equal to the median of the sum, if the distibutions ae lognomal. This appoximation is consideed to be adequate fo the puposes of the pesent analysis A1-16

18 lage cities Kyiv, Zhytomy, and Chenihiv. At the end of the table ae dose distibutions fo the evacuees. Age distibutions fo individuals with unknown gende ae given sepaately, as ecods of many measuements do not include that infomation. Second level of thyoid dosimety: settlement- specific thyoid doses Age and gende settlement-specific thyoid doses wee estimated fo 748 settlements of Kyiv, Zhytomy, and Chenihiv oblast whee thyoid activity measuements wee pefomed in May-June Fo evey settlement 36 thyoid doses (18 ages fo two gendes) wee estimated using values of f a,s (Table 2) and esults of the thyoid measuements made in the settlement. The distibutions of the numbe of settlements accoding to the thyoid dose fo the efeence age inteval ( D ~ a ) ae shown on Table 6. Thid level of thyoid dosimety: oblast specific thyoid doses Oblast-specific thyoid dose estimates fo 36 age- and gende goups ae shown in Table 7 fo 24 oblasts, Kyiv-city, the Cimean Republic, and the city of Sevastopol. The estimated thyoid doses fo diffeent Ukainian oblasts ae between 3 mgy (Zakapattya oblast) and 84 mgy (Zhytomy oblast). The thyoid doses fo paticula age and gende goups in Zhytomy oblast ae in the ange mgy, fo Kyiv oblast the ange is mgy; fo Chenihiv oblast the ange is mgy. Two othe oblasts with uppe ange doses in excess of 100 mgy ae Rivne oblast ( mgy), and Chekasy oblast ( mgy). In all cases, the highest doses ae estimated fo childen who ae 1o 2 yeas old. Futue wok The appoaches used fo thee levels of thyoid dose estimation summaize the cuent status of etospective thyoid dosimety achieved in Ukaine up to the yea In the famewok of the Ukainian-Ameican cohot thyoid study [21,22,31] the questionnaie-based instumentally individualized appoach is used to estimate the ef, j A1-17

19 individual thyoid doses. The othe appoaches ae employed in the ecological epidemiologic analyses of thyoid cance incidence afte the Chenobyl accident. At this point, it is also appopiate to identify a numbe of aeas of dosimetic eseach needed fo educing the uncetainty associated with thyoid dose estimations. Thee ae: - Modification of some paametes of iodine metabolism depending on the level of stable iodine in the diet. This is most impotant fo the condition of iodine deficiency, which was pevalent in nothen Ukaine at the time of Chenobyl accident; - Claification of the age-dependent thyoid mass fo the childen and adolescents of Ukaine at the time of Chenobyl accident, as influenced by the level of dietay iodine.. - Moe pecise desciption of efeence diets, especially fo young childen at the time of the accident. This is because estictions of milk and leafy vegetable consumption most likely wee applied by paents to this subgoup of childen. - Evaluation of the uncetainties of the 131 I deposition estimates and of the paamete values s used in the ecological model. - Evaluation of the doses eceived by childen aged less than 1 yea at the time of the accident. - Evaluation of the uncetainties in the models used fo the thee levels of thyoid dose estimation. Acknowledgements. This wok was suppoted in pat by Contact #4240 fom the Geman Fedeal Ministy fo Envionment, Natue Pesevation and Reacto Safety (Subcontact fom GSF - Foschungszentum fu Umwelt und Gesundheit), in pat by the U.S.National Cance A1-18

20 Institute and the U.S. Depatment of Enegy, and in pat by the Radiation Potection Institute of ATN of Ukaine. A1-19

21 Refeences 1. United Nations Scientific Committee on the Effects of Atomic Radiation. Souces and effects of ionizing adiation. UNSCEAR 2000 Repot to the Geneal Assembly, with Scientific Annexes. Volume 1: Souces. New Yok, N. Taleko, Reconstuction of 131 I Radioactive Contamination of Ukaine caused by the Chenobyl Accident using Atmospheic Tanspot Modeling. Repot fo NCI, N. Taleko, Mesoscale modeling of adioactive contamination fomation in Ukaine caused by the Chenobyl accident. Submitted to J. Envion. Radioactivity. 4. P. Jacob, G. Goulko, W.F. Heideneich, I. Likhtaev, I. Kaio, N. Tonko, T. Bogdanova, J. Kenigsbeg, E. Bugolva, V. Dozdovitch, A. Golovneva, E. Demidchik and V. Beal, Thyoid cance isk to childen calculated. Natue. 392, pp (1998). 5. I.A. Likhtaev, B.G.Sobolev, I.A.Kaio, N.D.Tonko, T.I.Bogdanova, V.A.Oleinic, E.V.Epshtein and V.Beal, Thyoid cance in the Ukaine. Natue, 375 (1), 365 (1995). 6. N. Tonko, T. Bogdanova, I. Komissaenko, S. Rybakov, A. Kovalenko, O. Epshtein, V. Oliynik, V. Teeshchenko, I. Likhtaev and M. Chepunoy, The Post-Chenobyl incidence of Childhood thyoid cance in Ukaine. In: Radiation and Thyoid Cance. Poceedings of an Intenational Semina. EUR EN. pp (1999). 7. N.D. Tonko, T.I. Bogdanova, I.V. Komissaenko, O.V. Epstein, V.A. Oliynik, A.Ye. Kovalenko, I.A. Likhtaev, I.A. Kaio, S.B. Petes and V.A. LiVolsi, Thyoid cacinoma in childen and adolescents in Ukaine afte the Chenobyl accident: statistical data and clinicomophologic chaacteistics. Cance. 86 (1), (1999). A1-20

22 8. N.D. Tonko, I.A.Likhtaev, I.A.Kaio and V.I.Shpak, Summay of the 15 yea obsevation of thyoid cance among Ukainian childen afte the Chenobyl accident. Chenobyl: Message fo the 21 st Centuy (S.Yamashita, Y.Shibata, M.Hoshi and K.Fujimua Eds.). Excepta Medica. Intenational Congess Seies, Elsevie, pp Amstedam, B. Sobolev, I. Likhtaev, I. Kaio, N. Tonko, V. Oleynik and T. Bogdanova, Radiaton isk assessment of the thyoid cance in Ukainian childen exposed due to Chenobyl. The adiological consequences of the Chenobyl accident. Poceedings of the fist intenational confeence on Mach in Minsk, pp Minsk, Belaus, N. Tonko, T. Bogdanova, I. Komissaenko et al. Thyoid cance in childen and adolescents in Ukaine afte the Chenobyl accident ( ). Poceedings of the fist intenational confeence on Mach in Minsk, pp Minsk, Belaus, T. Abelin, J. Avekin, A. Okeanov and J. Bleue, Thyoid cance in Belaus: the epidemiological situation. The adiological consequences of the Chenobyl accident. Poceedings of the fist intenational confeence on Mach in Minsk, pp Minsk, Belaus, L.N. Astakhova, L.R. Anspaugh, G.W. Beebe et al, Chenobyl-Related Thyoid Cance in Childen of Belaus: A Case-Contol Study. Radiation Reseach, 150, (1998). 13. E.P. Demidchic, I.M. Dobyshevskaya, E.D. Chestvoy et al, Thyoid cance in childen in Belaus. The adiological consequences of the Chenobyl accident. Poceedings of the fist intenational confeence on Mach in Minsk, pp Minsk, Belaus, A1-21

23 14. J. Kenigsbeg, E. Buglova, H. Paetzke and W. Heideneich, Pespectives of development of thyoid cance in Belaus. Poceedings of the fist intenational confeence on Mach in Minsk, pp Minsk, Belaus, Medical consequences of the Chenobyl accident. Results of pilot pojects IPHECA and espective national pogams. The scientific epot. Intenational Pogamme on the Health Effects of the Chenobyl Accident (IPHECA). The wold oganization of Public health sevices. Geneva 1995 (G.N.Sushkevich and A.F. Tsyb Eds.). Geneva, A.F. Tsyb, E.M. Pashkov, V.V. Shakhtain et al, Thyoid cance in childen and adolescents of Byansk and Kaluga egions. Poceedings of the fist intenational confeence on Mach in Minsk, pp Minsk, Belaus, V. Ivanov, A. Gosky, V. Pitkevitch, A. Tsyb, E. Cadis, H. Stom, Risk of Radiogenic Thyoid Cance in Russia Following the Chenobyl Accident. In Radiation and Thyoid Cance. Poceedings of an Intenational Semina. EUR EN, pp (1999). 18. V.K. Ivanov, A.I. Goski, A.F. Tsyb, Dynamics of thyoid cance incidence in Russia following the Chenobyl accident. J. Radiol. Pot., 19(4), (1999). 19. M. Balonov, G. Kaidanovsky, I. Zvonova, A. Kovtun, A. Bouville, N. Luckyanov, P. Voillequé, Contibutions of shot-lived adioiodines to thyoid doses eceived by evacuees fom the Chenobyl aea estimated using ealy in-vivo measuements. Radiat. Pot. Dosim., 105(1-4), (2003) 20. Y. Gavilin, V. Khouch, S. Shinkaev, V. Dozdovitch, V. Minenko, E. Shemiakhina, A. Ulanovsky, A. Bouville, L. Anspaugh, P. Voillequé, N. Luckyanov, Individual thyoid dose estimation fo a case-contol study of Chenobyl-elated thyoid cance among childen of Belaus. Pat 1: 131 I, shot-lived adioiodines ( 132 I, 133 I, 135 I), and shot-lived adiotelluiums ( 131m Te and 132 Te). Health Physics, 86 (6): (2004). A1-22

24 21. M.D. Tonko, O.O. Bobylyova, T.I. Bogdanova, O.V. Epshtein, I.A. Likhtayov, V.V. Makov, V.A. Oliynyk, V.P. Teeshchenko, V.M. Shpak, Paul Voillequé et al, Thyoid gland and adiation (Ukainian-Ameican Thyoid Poject). The Fist Nagasaki Symposium of Intenational Consotium fo Medical Cae of Hibakusha and Radiation Life Sciences. Nagasaki, Japan, V.A. Stezhko, E.E. Buglova, L.I. Danilova, V.M. Dozd, N.A.Kysenko, N.R.Lesnikova, V.F. Minenko, V.A. Ostapenko, S.V. Petenko, L.B. Zablotska, and at al, A cohot study of thyoid cance and othe thyoid diseases following the Chenobyl accident: objectives, design and methods. Chenobyl Thyoid Diseases Study Goup of Belaus, Ukaine, and the USA. Radiation Reseach (In pess). 23. P. Jacob, Y. Kenigsbeg, I. Zvonova, G. Goulko, E. Buglova, W. Heideneich, A. Golovneva, A. Batilova, V. Dozdovitch, H. Paetzke et al, Childhood exposue due to the Chenobyl accident and thyoid cance isk in contaminated aea of Belaus and Russia. Bitish Jounal of Cance. 80 (9), (1999). 24. Medical aspects of accidence on Chenobyl NPP. Mateials of scientific confeence on May Zdoov ya, Kyiv, 1988 (In Russian). 25. I. Likhtaev, L. Kovgan, S. Vavilov, R. Gluvchinsky, Z. Boyko, L. Belaya, V. Repin, V. Bekovsky, N. Novak, G. Sotnikova, and at al. Radiation dosimety passpottization of the settlements located on the teitoies of Ukaine adioactively affected following the Chenobyl accident (including passpotization of thyoid doses). Methodology ecommendations. Kyiv, 1996 (in Russian). 26. I.A. Likhtaiov, N.K. Shandala, G.M. Gulko, I.A. Kaio and N.I. Chepunoy, Exposue doses to thyoid of the Ukainian population afte the Chenobyl accident. Health Phys. 64 (6), (1993). 27. I. Likhtaev G. Gulko, B. Sobolev, I. Kaio, N. Chepunoy, G. Pöhl and K. Henichs, Thyoid dose assessment fo the Chenigov egion (Ukaine): estimation based on 131 I A1-23

25 thyoid measuements and extapolation of the esults to disticts without monitoing. Radiat and Envion Biophys. 33, (1994). 28. I. Likhtaev, B. Sobolev, I. Kaio, L. Tabachny, P. Jacob, G. Pohl and G. Goulko, Results of lage scale thyoid dose econstuction in Ukaine. The adiological consequences of the Chenobyl accident. Poceedings of the fist intenational confeence on Mach in Minsk, pp Minsk, Belaus, I. Likhtaev, I. Kaio, V. Shpak, N. Taleko, Thyoid etospective dosimety poblems in Ukaine: achievements and delusions. Radiation and Thyoid Cance. Poceedings of an Intenational Semina. pp EUR EN, Chenobyl: A Decade, Kiev, Ukaine, Octobe Poceedings of the 5 th Chenobyl Sasakawa Medical Coopeation Symposium (S. Yamashita and Y.Shibata Eds.), ELSEVIER, p.613, I. Likhtaev, V. Minenko, V. Kouch, and A. Bouville, Uncetainties in the thyoid dose econstuction afte Chenobyl. Radiat. Pot. Dosim. 105, 1-4 (2003). 32. Ministy of Chenobyl. Complex dosimetic passpotization of Ukaine settlements. Contact with the Scientific Cente of Radiation Medicine. Kyiv, 1992 (in Russian). 33. Ministy of Chenobyl. Complex dosimetic passpotization of Ukaine settlements. Contact 5/5c-96 with the Scientific Cente of Radiation Medicine. Kyiv, 1996 (in Russian). 34. ICRP Publication 56. (Annals of the ICRP Vol. 20 No. 2). Age-Dependent Doses to Membes of the Public fom Intake of Radionuclides: Pat 1. A epot of Task Goup of Committee 2 of the Intenational Commission on Radiological Potection. Pegamon Pess, Oxfod, H. Mülle and G. Pöhl. Ecosys-87: A dynamic model fo assessing adiological consequences of nuclea accidents. Health Physics. 64(3), (1993). A1-24

26 36. R. M. Bakhudaov, K. I. Godeev, I. K. Dibobes, I. A. Likhtaev, U. Ya. Magulis, D. P. Osanov, O. A. Pavlovskiy, B.S. Piste, M. N. Savkin and V. P. Shamov, Methodological pinciples of calculation of extenal and intenal exposue of population, used while opeative decision making. In Medical aspects of the accident on Chenobyl NPP. Scientific confeence mateials, May 11-13, 1988, pp Zdoov ja, Kiev, 1988 (in Russian). 37. ICRP Publication 67. (Annals of the ICRP Vol. 23 No. 3/4). Age-Dependent Doses to Membes of the Public fom Intake of Radionuclides: Pat 2. Ingestion Dose Coefficients. Pegamon Pess, Oxfod, A. Bühl, P. Zöfel, SPSS Vesion 10. Einfühung in die modeme Datenanalyse unte Windows. Addison-Wesley, an inpint of Peason education Deutschland GmbH. München, W.J. Conove, Pactical Nonpaametic Statistics. New Yok, Wiley, A. M. Mood, F.A. Gaybill and D.C. Boes, Intoduction to the Theoy of Statistics. Thid Edition, McGaw-Hill, p.p , List of footnotes. Page 4. 1 Raion is an administative unit within an oblast. Usually thee ae 10 to 20 aions in an oblast. The aion is compaable to a county in the United Stattes, while the oblast is compaable to a state. Page This is an appoximation as the sum of medians is not equal to the median of the sum, if the distibutions ae lognomal. This appoximation is consideed to be adequate fo the puposes of the pesent analysis List of figue legends Figue 1. Estimated cumulative 131 I deposition on the teitoy of Ukaine [2, 3]. Figue 2. Distibution of the numbes of diect thyoid measuements made in Ukaine in 1986 fo childen and adolescents. A1-25

27 Table 1. Numbe of Ukainian settlements whee diect thyoid measuements wee made in 1986 and numbe of the measuements. M is male, F is female, and Unknown coesponds to "gende is not given in ecod", Evacuees, Non-evacuees efe to measuements of pesons fom settlements which wee o wee not evacuated (esettled) in May 1986, espectively. Type of population Numbe of settlements Numbe of thyoid measuements Unknow F M Total n 1. Total amount of measuements pefomed at the settlements 1. All measuements ,628 52,,001 18, , Evacuees 53 4,911 4, , Non-evacuees ,717 47,724 18, , Settlements whee 10 thyoid measuements wee made by SRP and/o 4 measuements wee made by othe devices a) 2.1. Evacuees 51 4,079 4,069-8, Non-evacuees: Rual&Uban ,788 37,559-75, Rual ,453 20,153-40, Uban 36 17,335 17,406-34, Settlements with thyoid measuements in the efeence age-inteval of yeas old a) 3.1.Evacuees 49 4,069 4,049-8, Non-evacuees: Rual&Uban ,899 36,807-73, Rual ,566 19,401-38, Uban 35 17,333 17,406-34,739 a) Pesons whose gende was unknown ae not included to the analysis A1-26

28 Table 2. Values of the elative age and gende time-integated thyoidal 131 I activity, f a,s, estimated fo the uban and ual population and evacuees of Kyiv, Chenihiv and Zhytomy oblasts. The efeence age goup is y. M is male, F is female, GM is geometic mean; GSD is geometic standad deviation. f a,s values Non-evacuated population Evacuated population age, Uban Rual Uban & Rual yeas F M F M F M GM GSD GM GSD GM GSD GM GSD GM GSD GM GSD A1-27

29 Table 3. Raion-specific scale facto K scal s, aion fo aions in Kyiv, Zhytomy and Chenihiv oblasts. M is male, F is female, STD is standad deviation. Zhytomy Oblast Raion Gende Total numbe in aion Koosten' Numbe of settlements Numbe of settlements with diect measuements Mean K scal s, aion STD F M Kyiv Chenihiv Luhyny Naodychi Ovuch Olevs'k Boodianka Vyshhood Ivankiv Kyievo-Sviatoshyn Makaiv Polis'ke Kozelet's Ripky Chenihiv F M F M F M F M F M F M F M F M F M F M F M F M F M A1-28

30 Table 4. Values of paametes of function appoximating scaling factos fo the settlements of goup 3, K scal s, j * * estimated fo the diffeent subpopulations in the settlements without diect thyoid measuements; K scal s, j * * β =B σ Cs,. M is male, F is female, B and β ae the paametes of the function. Subpopulation B GM GSD Mean STD β Rual Uban M F M F A1-29

31 Table 5. Distibution of the instumentally-individualized thyoid doses due to the Chenobyl accident in Chenihiv, Zhytomy and Kyiv oblasts ove the age-sex goups. Age goup Numbe of Male Female Unknown gende All Dose Numbe of Dose Numbe of Dose Numbe of Dose (yeas) measuem GM GSD measueme GM GSD measuem GM GSD measuem GM GSD Chenihiv oblast, ual settlements All Chenihiv oblast, towns All Chenihiv-city All Zhytomy oblast, ual settlements All Zhytomy oblast, towns All A1-30

32 Zhytomy-city All Kyiv oblast, ual settlements All Kyiv oblast, towns All Kyiv-city All Chenihiv, Zhytomy and Kyiv oblasts, all settlements All Evacuated inhabiatnces All A1-31

33 Table 6. Distibution of settlements whee diect thyoid measuements wee pefomed in 1986 accoding to aveage thyoid dose among childen aged 12 to 14 (efeence age inteval). Oblasts a) No of settlements No of childen aged 1 to 18 in 1986 Numbe of settlements with thyoid doses to the efeence age-inteval in the indicated dose-inteval < mgy mgy mgy mgy >2000 mgy mgy mgy mgy Kyiv Zhytomy Chenihiv a) These esults do not include estimates fo the efeence age-goup in the lagest cities of the oblasts. Thyoid doses to the efeence age-inteval in Kyiv-city, Chenihiv city, and Zhytomy city ae estimated to be 18.6 mgy, 48.6 mgy, and 12.2 mgy, espectively. A1-32

34 Table 7. Oblast-specific thyoid doses (mgy) fo diffeent age and gende goups in Ukaine. Oblast Population Sex Aveage Age in Dose, mgy Kyiv Chenihiv Zhytomy Kyiv city Chekasy Rivne Kheson F M F M F M F M F M F M F M A1-33

35 Oblast Population Sex Aveage Age in Dose, mgy Kiovohad Vinnytsia Sumy Poltava Dnipopetovs'k Khmel'nytsk Donets'k F M F M F M F M F M F M F M A1-34

36 Oblast Population Sex Aveage Age in Dose, mgy Chenivsi Volyn' Ivano- Fankivs k Mykolaiv Odesa L'viv Khakiv F M F M F M F M F M F M F M A1-35

37 Oblast Population Sex Aveage Age in Dose, mgy Luhans'k Zapoizhzhia Tenopil' Zakapattia Cimea Sevastopol' city F M F M F M F M F M F M A1-36

38 Figue.1. Estimated cumulative 131 I deposition on the teitoy of Ukaine [2, 3]. A1-37