Page 1 of 14

DOE Review Release 09/21/2017

Extremity Doses for Mound Exposures to 

Plutonium-238

ORAUT-OTIB-0087 Rev. 00

Effective Date: 09/18/2017

Supersedes: None

Subject Expert(s): Mark R. Fishburn, Matthew H. Smith

Document Owner 

Approval: Signature on File

Mark R. Fishburn, Document Owner

Approval Date: 09/13/2017

Concurrence: Signature on File

John M. Byrne, Objective 1 Manager

Concurrence Date: 09/12/2017

Concurrence: Signature on File

Ali Simpkins, Objective 3 Representative

Concurrence Date: 09/14/2017

Concurrence: Vickie S. Short Signature on File for

Kate Kimpan, Project Director

Concurrence Date: 09/12/2017

Approval: Signature on File

James W. Neton, Associate Director for Science

Approval Date: 09/18/2017

FOR DOCUMENTS MARKED AS A TOTAL REWRITE, REVISION, OR PAGE CHANGE, REPLACE THE PRIOR 

REVISION AND DISCARD / DESTROY ALL COPIES OF THE PRIOR REVISION.

New Total Rewrite Revision Page Change
Document No. ORAUT-OTIB-0087 Revision No. 00 Effective Date: 09/18/2017 Page 2 of 14

 

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION

NUMBER DESCRIPTION

09/18/2017 00 New document initiated to calculate extremity to whole-body ratios 

for work performed at Mound for work with Pu-238. Incorporates 

formal internal and NIOSH review comments. Training required: As 

determined by the Objective Manager. Initiated by Matthew H. 

Smith.
Document No. ORAUT-OTIB-0087 Revision No. 00 Effective Date: 09/18/2017 Page 3 of 14

TABLE OF CONTENTS

SECTION TITLE PAGE

Acronyms and Abbreviations ............................................................................................................... 4

1.0 Introduction .............................................................................................................................. 5

1.1 Purpose........................................................................................................................ 5

1.2 Scope........................................................................................................................... 5

2.0 Background.............................................................................................................................. 5

3.0 General Approach.................................................................................................................... 5

3.1 Radioactive Profile........................................................................................................ 6

4.0 Applications and Limitations..................................................................................................... 6

5.0 Extremity Dose Ratio Development.......................................................................................... 6

5.1 Wrist-to-Whole Body Dose Ratios ................................................................................ 6

5.2 Finger-to-Wrist Ratios................................................................................................. 12

6.0 Summary ............................................................................................................................... 12

References ........................................................................................................................................ 14

LIST OF TABLES

TABLE TITLE PAGE

3-1 Gamma components from 238Pu............................................................................................... 6

5-1 Wrist-to-WB dose ratios ........................................................................................................... 8

5-2 Finger-to-wrist gamma dose ratios ......................................................................................... 12

LIST OF FIGURES

FIGURE TITLE PAGE

3-1 Neutron energy spectrum for 238PuO2 RTG .............................................................................. 7

5-1 Fit comparison for gamma ratio.............................................................................................. 11

5-2 Fit comparison for neutron ratio.............................................................................................. 11
Document No. ORAUT-OTIB-0087 Revision No. 00 Effective Date: 09/18/2017 Page 4 of 14

 

ACRONYMS AND ABBREVIATIONS 

AIC Akaike information criterion

DOE U.S. Department of Energy

keV kiloelectron-volt, 1,000 electron-volts

mrem millirem

NIOSH National Institute for Occupational Safety and Health

NTA nuclear track emulsion, type A

ORAU Oak Ridge Associated Universities

RTG radioisotope thermoelectric generator

SRDB Ref ID Site Research Database Reference Identification (number)

TIB technical information bulletin

TLD thermoluminescent dosimeter

WB whole body

U.S.C. United States Code

§ section or sections
Document No. ORAUT-OTIB-0087 Revision No. 00 Effective Date: 09/18/2017 Page 5 of 14

 

1.0 INTRODUCTION

Technical information bulletins (TIBs) are not official determinations made by the National Institute for 

Occupational Safety and Health (NIOSH) but are rather general working documents that provide 

historical background information and guidance to assist in the preparation of dose reconstructions at 

particular sites or categories of sites. They will be revised in the event additional relevant information 

is obtained about the affected site(s). TIBs may be used to assist NIOSH staff in the completion of 

individual dose reconstructions.

In this document, the word “facility” is used as a general term for an area, building, or group of 

buildings that served a specific purpose at a site. It does not necessarily connote an “atomic weapons 

employer facility” or a “Department of Energy (DOE) facility” as defined in the Energy Employees 

Occupational Illness Compensation Program Act of 2000 [42 U.S.C. § 7384l(5) and (12)].

1.1 PURPOSE

This TIB provides information about and comparison of whole-body (WB), wrist, and finger doses. 

This information may be used to determine ratios to assist in the determination of extremity doses. If 

worker extremity dosimeter results are available, those results should be used either as the dose to 

assign or as values from which a ratio can be calculated to better determine the dose to the cancer 

site, whichever is more appropriate.

1.2 SCOPE

The information in this TIB may be used to determine dose to assign to extremities while working with 

or around 238Pu at Mound, or other sites where exposure to 238Pu occurred, when WB dose or finger 

ring dose is available.

2.0 BACKGROUND

Some workers assigned to Mound had only WB dosimetry assigned to them. However, the work they 

performed might have included working “hands-on” with 238Pu, and it would be expected that the dose 

to the extremities would be elevated in comparison with the WB dose. For these workers an 

approach may be needed to assign dose to the extremities. Further, if finger ring dose is available, 

the wrist-to-finger ratios could be used to determine the dose to other parts of the hand.

3.0 GENERAL APPROACH

Information in Mound reports Wrist and Fingertip Dose Measurements for Plutonium-238 Processing 

Operations (Bigler 1973) and Extremity Monitoring Study of Personnel in Plutonium Operations (Bigler

and Phillabaum 1973) was reviewed.

Mound initiated a study in September 1972 to determine the need for extremity monitoring for 

personnel involved in 238Pu operations at the site. Wrist badges suitable for determining both neutron 

exposure using nuclear track emulsion, type A (NTA) film and gamma exposure using LiF 

thermoluminescent dosimeters (TLDs) were selected. The workers who performed the operations 

were monitored for various lengths of time ranging from 2 to 22 weeks with a 2-week dosimeter 

exchange frequency.

A study was also performed in 1972 and 1973 with wrist and WB gamma and neutron doses during 

work in gloveboxes where the workers were wearing leaded rubber gloves. The monitoring approach 

for detecting the gamma and neutron dose used the same monitoring approach (i.e., LiF TLDs and 

NTA film, respectively) as the other study. This study also involved taping TLDs to the finger tips on 
Document No. ORAUT-OTIB-0087 Revision No. 00 Effective Date: 09/18/2017 Page 6 of 14

 

the second or third finger of each hand to be able to determine the gamma dose to the finger tips. 

The number of days the dosimetry was worn ranged from 3 to 10 days.

The information in these reports can be used to determine the ratios of left wrist to WB and right wrist 

to WB for gamma and neutron radiation. Ratios for left finger to left wrist and right finger to right wrist 

gamma ratios for a limited number of applications can also be developed.

3.1 RADIOACTIVE PROFILE

Plutonium-238 is primarily thought of as an alpha emitter, but there are other emitted radiations that 

can contribute to external dose (Table 3-1). Table 3-1 provides the gamma energies and the percent 

of time that they are emitted (e.g., 13% of the time a gamma is emitted with 17 keV of energy).

Table 3-1, Gamma components from 238Pu 

(Foster 1966).

Gamma component

(keV)

Absolute intensities

(%)a 

17 1.3 × 101

43 3.8 × 10-2

99 9.0 × 10-3

150 1.0 × 10-3

203 4.0 × 10-6

760 5.0 × 10-5

875 2.0 × 10-5

a. Values are absolute intensities because not all 

disintegrations are accompanied by gamma emission.

When combined into plutonium oxide (238PuO2) for the purpose of a radioisotope thermoelectric 

generator (RTG), a spectrum of neutron energies as presented in Figure 3-1 are generated.

4.0 APPLICATIONS AND LIMITATIONS

The data from Mound were for workers who were involved in various activities involving 238Pu in 1972 

and 1973. This TIB can be used to determine dose to assign to extremities while working with or 

around 238Pu at Mound, or other sites when exposures to 238Pu (or similar energy spectrum) occurred, 

when only WB dose is available. In addition, calculated finger-to-wrist ratios can be used to 

determine finger dose from wrist or WB dosimetry results. In addition, the finger-to-wrist ratios can be 

used to determine the dose to other parts of the hand if finger ring dose is available.

5.0 EXTREMITY DOSE RATIO DEVELOPMENT

5.1 WRIST-TO-WHOLE BODY DOSE RATIOS

Information from the 1972 and 1973 reports on extremity monitoring of individuals during a number of

238Pu operations is presented in Table 5-1. The calculated value and distribution was determined 

from the dataset after the data was fitted using the Akaike information criterion (AIC). AIC is used to 

estimate the quality of a model relative to other models. For a gamma ratio (wrist-to-WB) the values 

were calculated using a Weibull distribution (see Figure 5-1). The values were determined to be 

1.3295 (shape of curve), 1.9271 (scale), and 0.3436 (location). For a neutron ratio (wrist-to-WB) a 

lognormal distribution with a geometric mean of 1.5796 and geometric standard deviation of 2.5414 

was determined to be most appropriate (see Figure 5-2).
Document No. ORAUT-OTIB-0087 Revision No. 00 Effective Date: 09/18/2017 Page 7 of 14

 

Figure 3-1. Neutron energy spectrum for 238PuO2 RTG (Anderson 1985).
 

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Table 5-1. Wrist-to-WB dose ratios.a,b

Individual doses - Pu-238 fuel processing

Employee

Left 

wrist, 

gamma 

(mrem)

Right 

wrist, 

gamma 

(mrem)

WB 

(mrem)

Left

wrist-toWB 

gamma 

ratio

Right

wrist-toWB 

gamma 

ratio

Left 

wrist, 

neutron 

(mrem)

Right 

wrist, 

neutron 

(mrem)

WB, 

neutron 

(mrem)

Left

wrist-toWB 

neutron 

ratio

Right

wrist-toWB 

neutron 

ratio

1 1,272 1,602 783 1.62 2.05 623 352 650 0.96 0.54

2 2,467 3,344 1,097 2.25 3.05 1,974 1,806 1,360 1.45 1.33

3 2,311 2,380 908 2.55 2.62 1,803 1,761 1,099 1.64 1.60

4 144 184 76 1.89 2.42 92 210 94 0.98 2.23

5 86 189 40 2.15 4.73 80 200 50 1.60 4.00

6 156 199 55 2.84 3.62 120 170 60 2.00 2.83

Individual doses - 

Handle encapsulated and project Pu-238 sources outside of glovebox and move sources within plant

Employee

Left 

wrist, 

gamma 

(mrem)

Right 

wrist, 

gamma 

(mrem)

WB 

(mrem)

Left

wrist-toWB 

gamma 

ratio

Right

wrist-toWB 

gamma 

ratio

Left 

wrist, 

neutron 

(mrem)

Right 

wrist, 

neutron 

(mrem)

WB, 

neutron 

(mrem)

Left

wrist-toWB 

neutron 

ratio

Right

wrist-toWB 

neutron 

ratio

1 371 344 239 1.55 1.44 634 554 349 1.82 1.59

2 118 N/M 133 0.89 N/A 202 N/M 194 1.04 N/A

3 N/M 175 187 N/A 0.94 N/M 282 273 N/A 1.03

Individual doses - Analytical determination of Pu-238 fuel used in sources

Employee

Left 

wrist, 

gamma 

(mrem)

Right 

wrist, 

gamma 

(mrem)

WB 

(mrem)

Left

wrist-toWB 

gamma 

ratio

Right

wrist-toWB 

gamma 

ratio

Left 

wrist, 

neutron 

(mrem)

Right 

wrist, 

neutron 

(mrem)

WB, 

neutron 

(mrem)

Left

wrist-toWB 

neutron 

ratio

Right

wrist-toWB 

neutron 

ratio

1 556 N/M 399 1.39 N/A 3,736 N/M 1,616 2.31 N/A

2 N/M 575 495 N/A 1.16 N/M 2,835 2,030 N/A 1.40

3 660 611 590 1.12 1.04 1,340 1,008 1,033 1.30 0.98
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Individual doses - Audit of Pu-238 encapsulation process

Employee

Left 

wrist, 

gamma 

(mrem)

Right 

wrist, 

gamma 

(mrem)

WB 

(mrem)

Left

wrist-toWB 

gamma 

ratio

Right

wrist-toWB 

gamma 

ratio

Left 

wrist, 

neutron 

(mrem)

Right 

wrist, 

neutron 

(mrem)

WB, 

neutron 

(mrem)

Left

wrist-toWB 

neutron 

ratio

Right

wrist-toWB 

neutron 

ratio

1 175 225 344 0.51 0.65 327 578 1,214 0.27 0.48

2 28 46 27 1.04 1.70 50 166 54 0.93 3.07

Individual doses - Encapsulation and decontamination of Pu-238 sources

Employee

Left 

wrist, 

gamma 

(mrem)

Right 

wrist, 

gamma 

(mrem)

WB 

(mrem)

Left

wrist-toWB 

gamma 

ratio

Right

wrist-toWB 

gamma 

ratio

Left 

wrist, 

neutron 

(mrem)

Right 

wrist, 

neutron 

(mrem)

WB, 

neutron 

(mrem)

Left

wrist-toWB 

neutron 

ratio

Right

wrist-toWB 

neutron 

ratio

1 269 N/M 71 3.79 N/A 237 N/M 169 1.40 N/A

2 N/M 518 397 N/A 1.30 N/M 1,222 4,105 N/A 0.30

3 265 403 282 0.94 1.43 2,001 4,836 2,202 0.91 2.20

Individual doses - Metallurgical evaluations and studies involving encapsulation of Pu-238

Employee

Left 

wrist, 

gamma 

(mrem)

Right 

wrist, 

gamma 

(mrem)

WB 

(mrem)

Left

wrist-toWB 

gamma 

ratio

Right

wrist-toWB 

gamma 

ratio

Left 

wrist, 

neutron 

(mrem)

Right 

wrist, 

neutron 

(mrem)

WB, 

neutron 

(mrem)

Left

wrist-toWB 

neutron 

ratio

Right

wrist-toWB 

neutron 

ratio

1 N/M 269 147 N/A 1.83 N/M 1,800 407 N/A 4.42

2 408 350 459 0.89 0.76 779 539 1,079 0.72 0.50

3 851 N/M 171 4.98 N/A 3,821 N/M 178 21.49 N/A

4 N/M 940 310 N/A 3.03 N/M 2,049 527 N/A 3.89

Individual doses - Handling of Pu-238 neutron sources

Employee

Left 

wrist, 

gamma 

(mrem)

Right 

wrist, 

gamma 

(mrem)

WB 

(mrem)

Left

wrist-toWB 

gamma 

ratio

Right

wrist-toWB 

gamma 

ratio

Left 

wrist, 

neutron 

(mrem)

Right 

wrist, 

neutron 

(mrem)

WB, 

neutron 

(mrem)

Left

wrist-toWB 

neutron 

ratio

Right

wrist-toWB 

neutron 

ratio

1 176 77 211 0.83 0.36 720 417 1,437 0.50 0.29
 

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Individual doses - Vacuum hot press operation of Pu-238 discs

Employee

Left 

wrist, 

gamma 

(mrem)

Right 

wrist, 

gamma 

(mrem)

WB 

(mrem)

Left

wrist-toWB 

gamma 

ratio

Right

wrist-toWB 

gamma 

ratio

Left 

wrist, 

neutron 

(mrem)

Right 

wrist, 

neutron 

(mrem)

WB, 

neutron 

(mrem)

Left

wrist-toWB 

neutron 

ratio

Right

wrist-toWB 

neutron 

ratio

1 115 188 27 4.26 6.96 192 254 N/M N/A N/A

2 N/M 339 138 N/A 2.46 N/M 122 52 N/A 2.33

3 764 N/M 296 2.58 N/A 5,065 N/M 287 17.64 N/A

4 63 72 33 1.91 2.18 126 137 40 3.15 3.43

5 31 34 7 4.43 4.86 28 49 28 1.00 1.75

Individual doses - Radiography and leak testing of Pu-238 sources

Employee

Left

wrist, 

gamma 

(mrem)

Right 

wrist, 

gamma 

(mrem)

WB 

(mrem)

Left

wrist-toWB 

gamma 

ratio

Right

wrist-toWB 

gamma 

ratio

Left 

wrist, 

neutron 

(mrem)

Right 

wrist, 

neutron 

(mrem)

WB, 

neutron 

(mrem)

Left

wrist-toWB 

neutron 

ratio

Right

wrist-toWB 

neutron 

ratio

1 145 226 258 0.56 0.88 961 1,598 596 1.61 2.68

a. N/A = not applicable.

b. N/M = not measured.
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Figure 5-1. Fit comparison for gamma ratio.

5.0% 90.0% 5.0%

5.4% 90.1% 4.5%

0.56 4.86

0

1

2

3

4

5

6

7

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

Fit Comparison for Gamma Ratio

RiskWeibull(1.3295,1.9271,RiskShift(0.34356))

Input

Minimum 0.3649

Maximum 6.9630

Mean 2.1160

Std Dev 1.3580

Values 55

Weibull

Minimum 0.3436

Maximum +∞

Mean 2.1156

Std Dev 1.3460

Figure 5-2. Fit comparison for neutron ratio.
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5.2 FINGER-TO-WRIST RATIOS

Information from the 1973 report on individuals wearing finger and wrist dosimeters was used to 

develop finger-to-wrist ratios (Table 5-2). A calculated average and standard deviation was 

determined from the limited dataset. The average was calculated to be 3.18 and 2.76 (left finger to

left wrist and right finger to right wrist, respectively). The associated standard deviations were 

calculated to be 0.53 and 0.85 (left finger to left wrist and right finger to right wrist, respectively). 

Since the data is limited, a fit comparison could not be determined and a normal distribution is 

recommended as a default value.

Unless it is known that an involved worker is right or left-handed, the higher ratio should be used (i.e., 

3.18 with a standard deviation of 0.53).

Table 5-2. Finger-to-wrist gamma dose ratios.

Individual Doses - Pu-238 fuel processing

Employee

Left finger 

(mrem)

Left wrist

(mrem)

Right finger 

(mrem)

Right wrist 

(mrem)

Left fingerto-wrist 

ratio

Right 

finger-towrist ratio

1 351 86 641 189 4.08 3.39

2 482 156 369 199 3.09 1.85

Individual Doses - Vacuum hot press of Pu-238 discs

Employee

Left finger 

(mrem)

Left wrist

(mrem)

Right finger 

(mrem)

Right wrist 

(mrem)

Left fingerto-wrist 

ratio

Right 

finger-towrist ratio

1 226 63 241 72 3.59 3.35

2 96 31 70 34 3.10 2.06

Individual Doses - Pu-238 heat source encapsulation

Employee

Left finger 

(mrem)

Left wrist

(mrem)

Right finger 

(mrem)

Right wrist 

(mrem)

Left fingerto-wrist 

ratio

Right 

finger-towrist ratio

1 237 83 200 50 2.86 4.00

2 158 66 76 40 2.39 1.90

6.0 SUMMARY

When it has been determined that a worker was exposed to a 238Pu and an extremity dose is needed 

use the provided wrist-to-whole body dose ratio and associated distributions to calculate the extremity 

dose from the whole body dosimeter dose.

As mentioned earlier, the following distributions and parameters best fit the evaluated data:

• Gamma ratio (wrist-to-WB), Figure 5-1. Weibull distribution, shape of the curve being 1.3295, 

scale being 1.9271, and location being 0.3436. This distribution is multiplied by the whole body 

dose to determine the wrist dose. 

• Neutron ratio (wrist-to-WB), Figure 5-2. Lognormal distribution with a geometric mean of 

1.5796 and geometric standard deviation of 2.5414. This distribution is multiplied by the whole 

body dose to determine the wrist dose. 

• There were too few data points when evaluating the finger-to-wrist information to obtain a

meaningful fit to a distribution. Since a meaningful fit could not be determined, assign data 

using a normal distribution. The average was calculated to be 3.18 and 2.76 (left finger to left 

wrist and right finger to right wrist, respectively). Unless specific information is known about 
Document No. ORAUT-OTIB-0087 Revision No. 00 Effective Date: 09/18/2017 Page 13 of 14

 

the workers handedness (i.e., right-handed or left-handed) use the more favorable mean of 

3.18 and a standard deviation of 0.53. This value is applied to the appropriate wrist dose to 

determine the finger dose. 

Additionally, finger doses can be determined if needed using the calculated mean finger-to-wrist 

ratios. If only a whole body dose is available for an Energy Employee, but a finger dose is needed, 

calculate a wrist dose using the provided wrist-to-WB ratio. Use this calculated dose and the fingerto-wrist ratio to determine the dose to assign to the finger.
Document No. ORAUT-OTIB-0087 Revision No. 00 Effective Date: 09/18/2017 Page 14 of 14

REFERENCES

Anderson, M. E., 1985, Neutron Flux, Spectrum, and Dose Equivalent Measurements for a 4500-

W(th) 238PuO2 General Purpose Heat Source, MLM-3248, Monsanto Research Corporation, 

Mound, Miamisburg, Ohio, May 9. [SRDB Ref ID: 3171, p. 64]

Bigler, W. A., 1973, Extremity Monitoring Study of Personnel in Plutonium Operations, Monsanto 

Research Corporation, Mound Facility, Miamisburg, Ohio. [SRDB Ref ID: 3281, p. 177]

Bigler, W. A., and G. L. Phillabaum, 1973, Wrist and Fingertip Dose Measurements for Plutonium-238 

Processing Operations, Monsanto Research Corporation, Mound Facility, Miamisburg, Ohio. 

[SRDB Ref ID: 3281, p. 203]

Foster, K. W., 1966, Gamma Shielding Requirements for Plutonium-238 and Polonium-210 (Revised), 

MLM-1315, Monsanto Research Corporation, Mound Facility, Miamisburg, Ohio, January 21. 

[SRDB Ref ID: 46890]