Hanford Whole Body Counter 1984 Activities

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HANFORD WHOLE BODY COUNTER 1984 ACTIVITIES This report describes the routine whole body counting measurement pro - gram for Hanford project personnel during 1984 and includes special studies and development work performed in conjunction with the whole body counting first report described the major facilities and equipment atthe whole body occurred. These reports are intended as summaries and are only distributed t o DOE-RL and the Hanford contractors. ROUTINE COUNTING PROGRAM Starting in 1978, similar annual reports have been written ; the Subsequent reports have described additions or changes that have Figure1 shows the --i nvivo measurements made a t the‘whole body counting The whole body counting section of which i s 10 percent higher than i n 1983. each bar, which includes all types o f measurements except lung counts, totaled 8176, which was about 12 percent higher than in 1983. for 1984 totaled 1768, which is only4percent higher than i n 1983 but lower personnel for each Hanford contractor, DOE, and private industries, which include Exxon Nuclear, U. S. Ecology, Pacific Nuclear and Allied Nuclear. This private work, which i s performed for private industry only to the extent that it does not impact on the service to DOE contractors,contrib - utes about $30K per year towards the support ofthe whole body counting ser - vices, thereby reducing the cost to DOE contractors.Figure2 shows the trends and usage ofthe whole body counting facilities over the past six years. The usage by Rockwell Hanford Operations (RHO) and U n i t e d Nuclear have remained atthe same level or decreased. @ n ly slightly higher than i n 1983 but RHO usage increased 20 percent i n 1984. The total number o f measurements for 1984 was 9944, Table 1 shows the number and type of measurements made on The usage by UNC i n 1984 was

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TABLE 1. --In Vivo Measurements Made in 1984 Counts Thyroid Wound In the 1984 routine counting program, 109 workers showed positive amounts o f gamma-emitting radionuclides. Thirty-three resu than 10 nCi and 76 were below this level but greater than 2 tion, there were 6 cases where workers had received medical radionuclides of 13lI or 2°1”202T1. There were 47 positive lung counts for 239Pu and 241Am, but most o f these were from previously known internal IN VIVO MEASUREMENT INCIDENT CASES Sixty-two Hanford DOE contractor employees were measured as a result of radioactive contamination incidents during 1984. ber of employees measured who were involved in incident cases to that of Table 2 compares the num-

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TABLE 2 . Number o f Employees Measured as a Result o f Ccntamination Incidents The types o f measurements made and the magnitude o f the internal contamination for the 1984 incidents is shown in Table 3'. TABLE 3. 1984 Incident Cases ( a ) Minimum detectabl e amount

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FACILITIES AND EOUIPMENT No major facility or piece of equipment was installed during 1984 a t the whole body counting facilities. and the six detector intrinsic germanium lung counting system which were installed in late 1983 were assessed i n 1984. The preview counter has pro - vid eda great reduction in the time needed t o process whole body counts and the germanium lung counting system has provided a very significant increase insensitivity for measuring low energy photon emitters such as 241Am, major equipment t o be added i n 1985 are described below: The usefulness ofthe Preview counter Some minor changes in facilities and plans for Wound Countinq Facilities at the Emergency Decontamination Center - A tai ned in operating condition at the Emergency Decontamination Center so that the measurement ofthe Pu content in wounds and the radioactivity removal procedures can be performed atthe same time in the same location. This procedure is a great improvement over the old procedure of transporting the person back and forth between counting and tissue excision facilities. Computer System Study - A computer system study ofthe whole body counter operations was completed i n FY 1984 by the Bat tell e Computer and Information Service Section. The conclusion of this study was that the existing Data General Nova computer with its RDOS operating system i s inadequate t o meet current and future needs. The study recommended the acquisition of a Dig i - tal Equipment Corporation VAX/730 or equivalent.This machine i s substanti ally more powerful than the Nova 4 . is a multiuser system rather than a two-user system. The recommended config u ration has 456 megabytes o f mass storage rather than the present 20 megabytes and has a substantially more powerful operating system than the presently used RDOS operating system. chased and developed software will be implemented as soon as possible. It has eight - times as much memory and This computer system will be pur - New Shielded Room - A new shielded room i s needed t o meet current and future demands for whole body counting services. The approval for construction, conceptual design and cost estimate, and functional design criteria were all

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FACILITIES AND EQUIPMENT (contd) ,completed i n 1984. The construction is scheduled for completion by October World War I1battleship steel stockpiled at the Nevada Test Sit e31, 1985. was transported to the 747A Building in November, 1984 for use inthe construction of the room. Second Set of Intrinsic Germanium Lung Detectors - Half of the detectors for the second lung counter were ordered i n 1984 t o be delivered in August 1984. The vendor i s having technical difficulties in the manufacturing and they were not delivered as ofthe end o f 1984. With the urgent need for the new computer the purchase ofthe remaining detectors to complete the second lung counter has been delayed until FY 1986 due to lack of capital equipment shielded room and then the measurement time for lung counts will be increased t o 33 minutes from the 16.7 minute counting time currently used. This will further increase the sensitivity for measuring low-energy photon emitters. Upon arrival,the second lung counter will be installed in the new A New Spectrum Analysis Procedure - A new method of analyzing high - resolution gamma-ray spectra to improve the reliability of the results from lung measurements has been developed and was briefly described in the 1983 report on the whole body counter activities. The new method involves applying avar i - ance stabilizing transformation channel by channel tothe spectrum resulting i n data with unit variance. transformed data by performing a nonlinear smoothing operation using a movwill be in units of standard deviations, thus simplifying the identification exceed 2.58 standard deviations is considered notto be significantly greater A background spectrum i s produced from the The difference between the transformed and background spectra Any data channel of the net transformed spectrum that does not This new method has been used for analysis of lung measurements for approximately six months and has proven t o be quite reliable,butis undergoing further testing before being fully adopted into the routine program.

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The data transformation and smoothing operations are rapidly performed by computer and easily verified by the operator, when necessary, using situation where analysis of high resolution spectra i s required. This method is applicable to virtually any New Operating Procedure For In Vivo Measurement Of High Energy Gamma-Rays - The following procedure was developed in the latter part of 1984 for implementation beginning January 2, 1985: body that are less than 2 nCi will not be reported. or greater, but less than 10 nCi, it will be determined and reported a s either a total body burden o r a lung burden, depending on' the distribution in the body. of the counts obtained in each of the 5 detectors in the Preview counter. If 50 percent of more of the activity is determined to be in the lung the quantity will be determined as a lung burden from the Preview counter measurement. If the quantity in the lung is less than 50 percent then it i s calculated as a total body burden from the Preview counter data. If the amount in the body is 10 nCi or more, the person is then measured with a scanning type counter to determine the exact distribution of the activity and the quantity in each organ or body part wil be determined. This new procedure will eliminate a large amount of time effort and record keeping that has been formerly spent on rather low leve s of radioactivity. If the amount is 2 nCi The distribution in the body will be determined using a ratio RESEARCH AND DEVELOPMENT ACTIVITIES Lung Calibration Studies In Females - The whole been participating in a study of the effects of measurements of 239Pu in females. In this study inhaling small quantities of Nb-92m at Harwell. body counter operation has chest wall thickness on lung female volunteers have been They are then measured at A similar study was con-several different laboratories around the world. ducted in males during the past few years and was reported in the 1982 whole body counter activities report. Five of the planned ten female studies were completed in 1983 and showed that the uptake of the Nb-92m tagged aerosol in

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RESEARCH AND DEVELOPMENT ACTIVITIES(contd) the lung is significantly lower in females,than in the male subjects. remaining five female studies has been delayed for about a year to study this difference in uptake and the reasons for it. The reason may be that females have smaller air passages leading to the lung. The studies on the remaining five females are scheduled to start in February o f 1985. These studies are important since an increasing number o f females are being employed as radiation workers. High Resolution Spectra Summing Of Radiation Worker Groups - With the excel - lent resolution of the intrinsic germanium planar detectors,radioactivity inthe summed spectra of a group o f workers can, i n some cases, be detected at levels lower than can be detected in their individual spectra. A s an example, the spectra of 29 people working with uranium, dhose.uranium content in the lungs was below the detect i or : limit for an individual routine count, were summed by t h e computer. clearly showed a 186 keV gamma-ray peak such that the average content in the lungs of the workers could be determined. was 0.02 nCi and the minimum detectable amount (MDA) for the combined counting time of 29 counts i s 0.01 nCi atthe 99 percent confidence level. The MDA for a single lung count i s 0.09 nCi. further application in radiation protection ' onthe Hanford project and i n studying groups o f uranium mine and mill workers. tion in monitoring trends in ALARA programs. The resulting spectrum in Figure3 The average amount in the lung This summing technique could have It may also have app lica - Phantom Measurements For Testing Of The Draft ANSI Standard N13.30 - The title of this Standard i s "Performance Criteria for Radiobioassay" and the testing involves both --i nvivo and --i n vitro measurement facilities.Ina p i 1o t study conducted during 1984 phantoms containing unknown amounts o f and 1311in the thyroid were circulated to many whole body counting fac il - i ties in the United States. evaluated in the three categories of minimum significant photon activity, bias and precision. ranged from 33 t o 93 percent. We are pleased to report that the Bat tell e Each measurement by the various facilities was The failure rates among the participating laboratories

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RESEARCH AND DEVELOPMENT ACTIVITIES (contd) whole body counter facilities made measurements on all the above radionuclides in all the phantom configurations and all of our results passed all of the tests. In the measurement of “+4Ce we were the only laboratory to successfully make an accurate measurement with the required sensitivity. This was.possible because of the availability of the 6-detector intrinsic germanium lung counting system and other state-of.-the-art equipment. study was conducted by Darrell Fisher and A1 Robinson o f the Radiological Calibration Studies Usinq Total Body Donations t o the U . S. Transuranium Registry - The opportunity to study whole bodies and make use of tissues f r o m persons having measurable burdens of transuranic radionuclides has significantly improved the accuracy with which skeletal burdens of 2 4 1 A m and 239Pu can be determined in living radiation workers by --in vivo counting (see Whole Body Counter Activity reports for 1979, 1981, and 1983). More bodies became available for study in 1984 and our calibration accuracy will continue to improve as more cases with different body sizes become available. In past studies the lungs and other internal organs had been removed before the bodies were made available for whole body counting studies and, therefore, only skeletal calibration studies were possible. Starting in 1985 we will be able to do studies on lung and liver calibrations. This will be possible because of a program started by the Registry where those people signed up for total body donations will receive a lung and liver count each year while they are still living. their death, will allow lung and liver calibrations t o be determined from the analysis of these organs after death. will be made available for study before the lungs and internal organs are of phantoms from bones from half of the analyzed skeletons, will be dcne with research funds and not from the routine whole body counter funding. These measurements, made within a year of Also the bodies of those who die The major portion of these studies, which include the construction

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Workers, Health Physics 47, pp. 632-634 (1984). PAPERS PRESENTED AT MEETINGS to Identify and Quant it ate Photopeaks i n Spectra Obtained From Whole Body Counter Examinations Employing High Resolution Detectors " , Annual Meeting of the Health Physics Society, New Orleans, June 3-8, 1984. Dogs, and Humans Exposed t o Radon Daughters and Uranium Ore Dust", Annual Meeting of the Health Physics Society, New Orleans, June.3-8, 1984. --I n Vivo Measurement o f Transuranic Nuclides", American Nuclear Society Meeting, New Orleans, June 3-8, 1984. on the Bio kinetics and Analysis of E afi in Man", Richland, Washington, Analysis of High Resolution Gama Spectra", Thirtieth Annual conference on Bioassay, Analytical, and Environmental Radiochemistry, Cincinnati, Ohio, -I n Vivo Measurement o f Uranium and Transuranic tio X Symposium on the Assessment o f Radioact Paris, France, November 19-23, 1984. anar Germanium Detectors f o r ve Contamination i n Man, " Calibration of Whole Body Counters for Transuranic Radionbcl ides by Using Symposium on the Assessment o f Radioactive Contamination i n Man, Paris,

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WHOLE BODY COUNTING STAFF H. E. Palmer Staff Scientist and Technical Leader B.W. Perkins Electronics Technician (assigned from Craft Development Engineer, Routine Operations