Comparison of Excretion Analysis with Whole-Body Counting for Assessment of Internal Radioactive Contaminants - Proceedings of the Symposium on the Assessment of Radioactive Body Burdens (Vol 1)

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OF RADIOACTIVITY IN MAN PROCEEDINGS O F THE SYMPOSIUM ON THE HELD BY THE INTERNATIONAL ATOMIC ENERGY AGENCY, INTERNATIONAL LABOUR ORGANISATION WORLD HEALTH ORGANIZATION In two volumes INTERNATIONAL ATOMIC ENERGY AGENCY

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This Symposium on the Assessment of Radioactive Body Burdens in Man was organized jointly by the International .Atomic Energy -4gency. the International Labour Organisation and the World Health Organization and was held in Heidelberg from 11 - 1 5 RIay 1964. It was attended by 181 participants from 28 countries and 6 international organizations. It was the objective of the Symposium to bring together experts from the various scientific disciplines of physics, chemistry, biology, medicine and mathematics, and to survey their experience in the assessment of radioactive body burdens in man and the resultant radiation doses. In most investigations of internal contamination the errors in the physical measurements are smaller than the errors associated with the interpretation of measurements. For this reason special emphasis was laid in this meeting on the interpretation of measured data. The 67 papers and the discussions which they stimulated a r e published in these Proceedings produced in two volumes. Volume I includes all Papers which deal with problems generally common to many 1SOtOpeS: &- vivo counting, bioassay techniques, sample counting and analysis of data. Volume II includes those papers concerned with radioisotopes of specific elements: caesium, radium, radon, strontium, tritium, thorium, uranium. plutonium and rare earth elements. These Proceedings should prove invaluable to all radiation protection services entrusted with the physical surveillance of internal radiation exposure of man. They should complement the studies of the International ’ Commission on Radiological Protection (ICRP)and assist the work of the Organizations that jointly organized the meeting. The three Organizations wish to express their appreciation to the Government of the Federal Republic of Germany for its generous invitation and to the scientists who contributed the valuable new information.

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CONTENTS OF VOL. I Formulation of relationships between the radiation exposure of tissues and the excretion rate of nuclides (SM-52/81) ................... 3 radioactivity in man: a historical and critical review (SM-52/58).. On the development of devices for the determination of total-body A two-crystal scanning-bed counter for accurate determination thorium in living persons (SM- 52/36) .......................... 67 A new technique for determining the distribution of radium and Shapes of scintillation spectra (SM-52/46)........................ Human beta bremsstrahlung detection by means of thin and thick sodium iodide crystals (SM-52/47)............................. in human lungs (SM-52/17).................................... An improved chest phantom for studies of plutonium and americium traces de plutonium dans les poumons (SM-52/26) ............... 131 Performance of an arrangement of several large- a r e a proportional counters for the assessment of Pua9 lung burdens (SM-52/56) .... 141 Fouveau compteur proportionnel destind a la detection in vivo de sapling and analysis for assessment of body burdens (SM-52/31)... 155 Authority for the determination of radionuclides in urine A survey of the methods used in the United Kingdom Atomic Energy Recent radiochemical procedures for bio-assay studies at Trombay Elizabeth Koshy, Urmila S. Waingankar and Vasanti S. Khailolkar

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Comparison of excretion analysis with whole-body counting for assessment of internal radioactive contaminants (SM-52/39) ...... 217 The role of faecal analysis in a bioassay programme (SM-52/10) .... 231 . Radiochemicd determination of plutonium for radiological purposes A procedure for the determination of alpha-emitting plutonium in activity in human tissues (SM-52/2) ............................ 291 A double-filter device to measure radon and thoron in the breath Total counting and spectroscopy in the assessment of alpha radioThe use of gamma-ray scintillation spectrometry in bioassay Interpretation of bioassay data (SM- 52/89) ........................ 329 Influence of aerosol properties and the respiratory pattern upon bone-seeking radionuclides and assessment of absorbed dose A critical survey of the analysis of microscopic distribution of some List of Chairmen of Sessions and Secretariat of the Symposium ..... 395

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COMPARISON OF EXCRETION ANALYSIS WITH INTERNAL RADIOACTIVE CONTAMINANTS HEALTH AND SAFETY DIVISION, UNITED STATES ATOMIC ENERGY COMMISSION, DAH0 FALLS, IDAHO, UNITED STATES OF AMERICA COMPAPJSON OF UCRETION ANALYSIS WITH WHOLE-BODY COUNTING FOR ASSESSMENT OF INTERNAL RADIOACTIVECONTAMINANTS. since the beginning of the atomic enugy era. rhe detection and derumination of internal conurnhation by radionuclides has dep ded primarily on h e routine examination of urfne. During the p u t three yean. the-0 wholebody counting programme canied out at the National Reactor Testing S t a w n has dunauuated clearly that UrlMlyrir h grooly hadequare as a gurual -morplroring technique h internal coourninants. ~hiny-onedifferent radicuuclldu have k e n encounrered 4molybdenum-&dum- 99 were excreted significaiXly in the &e. Tbe orbu nuclides W W & h r c d I)exclmlvely In rhc faeces u t . except for an occasiooll trace. the nuclide could not be derccud even fn a 1500-ml mine m p k . Th cmchnton seerm clear thu for inhalation of particulacu. rhe meubolic face will k mote dependent O(L physicll pr~percluof the parrick with which the nuclide & urociated th.n *with the chemical pm pur iu of the elmenr its&. The effective half- liva and modes of exctction am prcwted far many of the nuclldu urcounrercd. -In vivo whole-body councfng rwidr many of the pmblemr of excrcrioo analysis for gamma emlmn. and rhe conrinuing costs of working time lost while rhe subjecrs being couuted are away from rheir jobs. A new inmument Is described in which the heavy shielding normally associated wirh whole-body counten is ellmhated (0 aehieveporubillty and reasonahb costs that most hboratoria can afford. The pmtocype weighs h u t 640 pounds and can be mounted in a small van to permit moving the counter to different reactor r I € u tu Increase the coverage for rhe =me cost. yet. appmxlmately 0.01 p c of caesium-137 can be detected in a 1 5 m b counr. a level that Is more hm adequate for practical personnel protection. ET DE L'ANTHROPCGAMMAME. Depuis I'avtnement dc l'trc atomique. la dttection d e la coatrminadoa interne et la dttermination de la charge corporclle ont repod wentiellemeat sur l'examen rtgulier d u urina. nationale d'euai d u rCacteun. a clairement dtmootrt que I'analysc der urine Ctait loin de cnnstlruer une &!bode satisfaisante de contdle de la contamination interne. Sur lu 31 radionucltidu dlfftrcnu qui ont M k i . O n n'a mime pas pu en dtceler dans un Cchanrillon d'urine de 1500 cma. I1 semble donc clairemenr UI W K i r que le son mttabolique d'une subsrance parriculaire inhalte dtpendra davantage d u propKi6tds physiques de la puricule L laquelle est luocit! le nucltide que d u propritttr chirniques de I'titmenl hi-mdme. Lu auteurs indiquent la @ride rtelle et les m o d e d'cxcrttion d'un grad nombre d e radionucltides dlceltr. L'anduopgrmmamtrrie asupprime un grand nombm des probltmes inhCrenu au dmagc des tmetteurs gamma dam lu; excrttiom. Toutefois. I'anthropog~mrnamCtrie err une mtrhode gh t rale ment EoateUK. tlOt en raison du prix de l'appareil que des h z u k perduu par les sujerr suivis qui dolvent K rendre loin du lieu de leur navail. Lu auteurs dtcrtvent un aouvel apparel1 dans lequel on a supprimt le iourd blindage dont un anrhropogammamkrre est norrnalement rnuni. de manikre L le rendre pcrtadf et asscz bon rmrch.6 pour la plupur d u Iaboratoiru. Le prototype p h enviroa 320 kg et on peur Le fixer sur une petite Camionnettc. c c qui pennet de aanspter I'appareil dam plusieun centres de rtacteun, et aitui d ' a c c m ~ h

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le wm bnd u ~USOIUIU examink ram augmenccr ler dbpcnru. Acolellemcnr. ax pur ddceler. apdr une pCri0d.e de compuge de 10 min, envimn 0.01 uc de cesium 137. tcndementpluquc aufflrrnc pour IPURI en prarlquc la prorccrloo du pcnonoel. aapaxenms pann on to ron a ~ n~ an uc en or naan u Y o6paaou OT 0 6 ~ unor oncc.aezonannn Mow. OcynporpauYv ~ 3 ~ epcnw npawoaxrwmocrw nccro oprannaua eacno nora i a ~ onedocrafowoctb ann Ynornx pac c var pna acv v x paswowloronon. N ALU Al X6N DE LOS CONTAMINANTES RADUCTIVOS INTERNOS: COMPARAmN DE LOS WUL - TACOS DEL ANkISIS DE U S MCRECIONES Y DE LA ANTROPOGAMMAMETPfA. Dude el com fu w de k era de k energfa arbmfu. la deccc& y decuminacibn de la coucamlnrldn inruna provocada por lor rdioaScUoa se ha buado ptincipahnacc en a dlls i a priddiccn de orlna. En lor dlrimor ma aac6, el prograna de anoopagamm&me~x o que se daanoUa o la NaLtonal Rucror Turing Sutim ha demauado cluamentc que el millsfade orirra d f i u mucbo de set cficaz como c6cnIca de vigilancia radioldgica general de lor conuminantu inremor. Efectivamen?c. la anclopogarnmameu'fa ha dernonrado la pruencla en el cuerpo hurnrno de 32 radfondclfdor diferentu de loa cualu solamente e l yodo-131-133. el cuio-134-137. e l rnercurlo-197-203 y el mollbdcw-cecnecio-99 se exerecan en cantidad rignlfiudva UL la o r b . Loa ndclida r url ntu $e elfminan de modo tan exclualvo p r Ida hecer que. salvo algh vetriglo ocasioml. no podrfa ducllbrlne N pruencla n i aun en una m u u v a de orha de 1500 ml. Sc Impcue. puu. la concluai6n de que. en lo que t u p e c u a la lnhalacfdn de macmpudculu. el cuno de meubolltmo dependeri rnL de lu propiedadu ffsicu de la parrlcula con que uti rclaciondo el ndclido que de lu propiedader qUrmicu del elemento en it. Lor autora pruenun 101 pcrrodar efececdvoa y lor medm de ucrccidn para muchos de lor ndclldor hallador. Con la muopogammameafa. se cvita gran parre de lor pmblernu que planrea el annllLL de lu excrecionu en la dcterminaci6n de ernhru gamma. Sin embargo. lor antmpogarnmhmcmr son generllmente oneroaor. tanto si se coluidero el precb original del equipo como lor cams conupondienror a1 ricmpo d e nabajo perdldo micntras l a ~ jero rm mtida al teaento pumaneccn Lcpr de sua PUUM. Lm autore ducriben un nuevo inrwmento en el c u d . a fin de faciliur m auuportc y reduck el prccio a lo que puede pagar rumablemenre la mayorfa de la laboratorior. re ha elhlnado el puado blindaje que normalmate requiem lor lompogammdrnetms. E l prototipo de estc nueva aparato p e a aproximadamenre 640 Libras y puedemonrarsc robce un pequello vehfculo que permite traIIipoRul0 a diferentu lugares en e l reactor p r a romentrr l u aplicacioncr sin inctementar el c a m . El aparato permite. no obstante. detectar con un recuenco de 1 0 min 0.01 gc de crrio-137. ut0 el. un valor mdr que suficiente para asegurar ptScticarnente l a proteccidn del

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COMPARISON EXCRETION ANALYSIS WITH WHOLE-BODY COUNTING 219 Since the beginning ofthe atomic energy era, detection and determination of internal contamination from radioactive nuclides has been accomplished almost universally by examination of urine. Although the possibility of inhalation or ingestion of insoluble particulates with subsequent elimination through the gastrointestinal ( G I ) tract has been widely recognized, most workers have assumed that enough of the active materid will always be either soluble or solubilized in the body and subsequently eLiminated in the urine t o permit urinalysis to be used reliably for the routine detection of internal contamination. Even in the soluble form, many elements a r e still eliminated predominantly by way of the GI tract. The increased use of in vivo wholebody counters in recent years for the detection of gamma-emitting nuclides in human subjects has demonstrated conclusively that analysis of urine is not adequate as a general technique f o r the detection of internal contaminants. The point of emphasis is not only that the radionuclides will not be present h the urine, but also that such a high percentage of the radioactive contaminants to be encountered are likely'to be in the form of insoluble particulates, especially around operating reactors. This paper presents the experience gained in over three years of whole-body counting at the National Reactor Testing Station (NRTS) in the United States which encompasses perhaps the largest concentration of operating reactors of different types t o be found anywhere in the western world. Thirty-one different radionuclides have been identified in h u m a n subjects from approximately 4000 whole-body examinations of nearly 2000 individuals. Where possible, the effective half-lives and modes of elimination of the various nuclides have been determined. Finally, a portable and relatively inexpensive counter has been developed so that most laboratories can take advantage of the sensitivity and freedom from many of the problems associated with excretion analysis that can be obtained by direct in vivo counting of human subjects. The whole-body counter employs a shield of pre-atomic era, armour plate steel, 11 in thick. The shield is in the form of a cylinder, 54 indiam., 94 in in length, and 5.5 in thick, with an additional flat piece 5.5 in thick added to the top, bottom and both sides. Both ends of the cylinder areclosed with a double layer of the 5.5-in plate with the plates on one 2nd beinghinged to form an 11-t door. The inside of the cylinder is lined with 1/4 in of lead. The detector consists of a 4-in thick by 8-in diam. thallium-activated sodium iodide crystal optically coupled to three matched multiplier phototubes. To minimize backscatter, the assembly is mounted near the centre of the counting shield but can be programmed to scan the subject in two directions. The output of the detector is fed into a 400-channel transistorized pulse-height analyser, and the resulting spectra can be either printed Out digitally by an I B M typewriter, plotted graphically on an X-Y recorder, or punched out on paper tape. Actually, all three methods a r e used: the graph f o r visual examination, the digital printout (which is printed on the same piece of graph paper containing the plot) for easy filing for a permanent record, and the paper tape for analysis. The punch tape is read directly

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C.W. SILL et al. into a high-speed electronic computer for data reduction. To make the counting rate as independent a s possible of the distribution of the radionuclide w i t h i n the body, the subject reclines in a chair that positions the body on a 50-cm a r c around the detector with the legs below the knee remaining horizontal for comfort. The head is also tilted backward slightly to decrease the shielding of the thyroid gland by the chin. T w o new counters with cubical shields approximately 9 ft on each inside dimension a r e presently nearing completion to replace the one described Experience has shown that it is generally not necessary for the subjects to take a shower before being counted for routine surveillance. This minimizes the time lost by each individual from his normal work. The subject is required to change from street clothes to a disposable paper examination gown to prevent possible contamination of the counter. The disposable paper gowns a r e more convenient to keep on hand in quantity and less expensive to use than cotton coveralls. The analysis usually shows nothing abnormal i n the spectrum so …