ORAU TEAM

Dose Reconstruction

Project for NIOSH

Oak Ridge Associated Universities I Dade Moeller & Associates I MJW Corporation

Page 1 of 14

Document Title:

Weldon Spring Plant – Occupational 

Medical Dose

Document Number: ORAUT-TKBS-0028-3

Revision: 00

Effective Date: 06/24/2005

Type of Document: TBD

Supersedes: None

Subject Experts: Theresa Lopez and Joseph Furman

Document Owner

Approval: Signature on File Approval Date: 06/20/2005

Robert Meyer, TBD Team Leader

Approval: Signature on File Approval Date: 06/20/2005

Judson L. Kenoyer, Task 3 Manager

Concurrence: Signature on File Concurrence Date: 06/20/2005

Richard E. Toohey, Project Director

Approval: Signature on File Approval Date: 06/24/2005

James W. Neton, Associate Director for Science

 New Total Rewrite Revision Page Change

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

PLEASE DISCARD / DESTROY ALL COPIES OF THE PRIOR REVISION.
Document No. ORAUT-TKBS-0028-3 Revision No. 00 Effective Date: 06/24/2005 Page 2 of 14

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION

NUMBER DESCRIPTION

03/24/2005 00-A New technical basis document for the Weldon Spring Plant –

Occupational Medical Dose. Initiated by Robert Meyer.

04/27/2005 00-B New technical basis document for the Weldon Spring Plant –

Occupational Medical Dose. Initiated by Robert Meyer.

06/13/2005 00-C Revised in response to OCAS comments. Initiated by Robert Meyer.

06/17/2005 00-D Revised in response to an additional OCAS comment. Initiated by 

Robert Meyer.

06/24/2005 00 First approved issue. Training is not required. Initiated by Robert 

Meyer.
Document No. ORAUT-TKBS-0028-3 Revision No. 00 Effective Date: 06/24/2005 Page 3 of 14

TABLE OF CONTENTS

Section

Publication Record ..............................................................................................................................

Page

2

Acronyms and Abbreviations ...............................................................................................................5

3.1 Occupational Medical Dose ........................................................................................................6

3.1.1 Introduction ........................................................................................................................6

3.1.2 Examination Frequency......................................................................................................7

3.1.3 Equipment and Techniques................................................................................................7

3.1.4 Organ Dose Estimates .......................................................................................................8

3.1.4.1 Parameters and Estimation Method........................................................................... 8

3.1.4.2 Organ Dose Estimates for WSP Workers ................................................................ 10

3.1.5 Uncertainties ....................................................................................................................10

References ........................................................................................................................................14
Document No. ORAUT-TKBS-0028-3 Revision No. 00 Effective Date: 06/24/2005 Page 4 of 14

LIST OF TABLES

Table

3-1 Default entrance kerma by procedure and time period (ORAU 2005).................................

Page

8

3-2 Modified ICRP dose conversion factors; absorbed dose (1 mGy) for organs at various Al 

HVL for chest radiography (ORAU 2005)(a)....................................................................... 10

3-3 Analogs for IREP organs not specified in ICRP (1982)..................................................... 10

3-4 Organ dose estimates for chest x-rays (rem) as presented in ORAU 2005....................... 11

LIST OF FIGURES

Figure

3-1 Kerma in air at 1 meter from X-ray source as a function of total filtration for 

various values of tube potential ..........................................................................................

Page

9
Document No. ORAUT-TKBS-0028-3 Revision No. 00 Effective Date: 06/24/2005 Page 5 of 14

ACRONYMS AND ABBREVIATIONS

CFR Code of Federal Regulations

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

HVL half value layer

ICRP International Commission on Radiological Protection

IREP Interactive RadioEpidemiological Program

kerma initial kinetic energy of charged particles liberated by uncharged ionizing radiation per 

unit mass 

LAT lateral

NCRP National Council on Radiation Protection and Measurements

NIOSH National Institute for Occupational Safety and Health

PA posterior-anterior

SID source-to-image distance

SSD source-to-skin distance

TBD technical basis document

U.S.C. United States Code

WSP Weldon Spring Plant
Document No. ORAUT-TKBS-0028-3 Revision No. 00 Effective Date: 06/24/2005 Page 6 of 14

3.1 OCCUPATIONAL MEDICAL DOSE

As part of the requirements for employment at the Weldon Springs Plant (WSP) from 1955 through 

1966 (the WSP operational period) and from 1986 through the present, all employees received 

periodic physical examinations. These could include annual radiographic examinations of the chest,

as directly and indirectly referenced in site-related reports (Mason 1955; Quigley and Mason 1963) 

and periodic chest x-ray examinations for remediation workers exposed to asbestos or using 

respirators (Lopez 2004). The National Institute of Occupational Safety and Health (NIOSH), in its 

role to reconstruct occupational dose under the Energy Employees Occupational Illness 

Compensation Program Act of 2000 (EEOICPA), 42 U.S.C. §§ 7384-7385, has classified diagnostic 

medical x-rays administered in conjunction with routine or special physical examinations required for 

employment as occupational exposures (NIOSH 2002). This technical basis document (TBD)

discusses medical exposures required as a condition of employment; it does not include diagnostic 

and therapeutic procedures because they were not required for employment. In addition, this TBD

provides dose estimates for workers who might have been present between 1966 and 1985, including

security personnel who might have received x-ray examinations as a requirement of employment. It 

also provides estimates for post-1985 remediation personnel.

TBDs and Site Profile documents are general working documents that provide guidance concerning 

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). These documents 

may be used to assist NIOSH in the completion of the individual work required for each dose 

reconstruction.

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 facility” as defined in the EEOICPA (42 U.S.C. § 7384l 

(5) and (12)).

The following subsections of this TBD describe the methodology used to estimate absorbed dose 

from x-ray exposure for WSP workers. In the absence of available data, assumptions are claimantfavorable. Section 3.1.1 provides introductory text. Section 3.1.2 describes x-ray examination 

frequency at WSP. Section 3.1.3 provides information on equipment and techniques used at WSP, 

including assumptions necessitated by lack of protocol, measurement, or records data. Section 3.1.4 

provides organ dose estimates by calendar year and type of x-ray. Section 3.1.5 documents 

uncertainties.

3.1.1

As described in Protection of the Patient in Diagnostic Radiology (ICRP 1982), the amount of energy 

absorbed in the body and its distribution in specific organs can be determined by measurement or 

calculation. Absorbed dose in tissue, measured in units of gray (Gy), is equal to the energy absorbed 

per unit mass at a point in the human body. The current international system of units expresses this 

quantity in air kerma. 

Introduction

The radiation dose received in a given examination varies widely throughout the body. Doses are 

highly dependent on the technical factors employed, characteristics of the equipment, collimation of 

the beam, and number of films taken. The general equation for total annual occupational medical 

dose provided by NIOSH (2002) guidelines is:

Dom = ΣnDi (3–1)
Document No. ORAUT-TKBS-0028-3 Revision No. 00 Effective Date: 06/24/2005 Page 7 of 14

where

Dom = occupational medical dose

n = number of exams in a calendar year

Di = dose from the x-ray procedure

The NIOSH guidelines state that medical records should contain the dates, types, and number of xray examinations, and that if there is no known information about the energy spectra, values should 

conservatively be assumed to be in the 30- to 250-kV photon range (a claimant-favorable 

assumption). The guidance states that the uncertainty distribution about each x-ray procedure is 

assumed to follow a normal distribution, with Dom being the mean dose.

3.1.2

The frequency and type of x-ray examinations are referenced in reports for WSP workers from 1955 

through 1966 (Thornton and Johnson 1965, Mallinckrodt 1965). Neither a protocol for the frequency 

of chest x-ray examinations as a function of job category nor a reference to any other type of x-ray

examination has been located. However, the references clearly indicate that chest x-ray

examinations were performed annually from 1955 through 1966, and medical records indicate that 

both posterior-anterior (PA) and lateral (LAT) views were taken. Therefore, the analysis for this TBD 

assumed annual PA and LAT chest x-ray examinations for all employees, and considered no other 

view. A review of pre-1970 files indicates that, approximately 30% of the time, workers received two

sets of chest x-rays in a period of 9 months or less (excluding x-rays for termination of employment);

the files do not provide reasons for this. The analysis assumed that the same frequency of chest xray examinations would have been used for security personnel present from 1966 through 1985. 

Examination Frequency

For the post-1985 remediation period, some workers might have received chest x-ray examinations;

such examinations might not have been mandatory on an annual basis. Specifically, respirator users 

or asbestos workers were probably required to have chest x-rays for the first medical examination, 

after which x-ray examinations occurred every 2 or 5 years depending on the work performed; this 

analysis assumed that PA and LAT chest x-rays were performed at each examination (Lopez 2004).

3.1.3

The analysis assumed that WSP radiological practices followed standards of medical practice to

minimize dose to the patient; however, the type of equipment, technique factors, and machine 

calibrations are not known. According to Thornton and Johnson (1965), a medical x-ray unit was 

present on the site; a report dated January 1966 indicates that it was used regularly and that x-rays 

were read by an offsite radiologist. Quigley and Mason (1955) indicate that chest x-ray examinations 

occurred at Barnes Hospital Laboratories, presumably prior to the installation of onsite equipment. To 

date, there has been no indication in either the available protocol or in worker medical files that 

photofluorography was ever used at WSP. 

Equipment and Techniques

This TBD provides organ dose estimates from occupational x-ray examinations administered at WSP

from 1955 through 1966 (pre-1970), 1970 to 1985, and post-1985 using default dose estimates from 

Technical Information Bulletin [TIB]: Dose Reconstruction from Occupationally Related Diagnostic Xray Procedures (ORAU 2005). For the years before 1970, the default values assume minimal beam 

collimation and a half-value layer (HVL) of 2.5 mm Al. For 1970 to 1985, the default values assume 

that the beams were collimated and the HVL was 2.5 mm Al. For post-1985, the default values

assume collimation and an HVL of 4.0 mm Al.
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For all periods, the analysis assumed that PA and LAT chest x-rays occurred at hire, at each annual 

physical examination, and at termination of employment, as evidenced by available protocols. 

Records of machine settings are not available so this TBD uses default estimates for LAT and PA 

chest x-rays from ORAU (2005). 

Efforts will continue to locate related WSP information. Until more accurate records are located, these 

assumptions provide the only available estimates.

3.1.4

This section discusses organ dose estimates. Section 3.1.4.1 describes the methodology used to 

estimate these doses, and Section 3.1.4.2 discusses results.

Organ Dose Estimates

3.1.4.1 Parameters and Estimation Method

Measured air kerma data should be the basis or organ estimates, if available. If these data are not 

available, air kerma rates can be estimated from Figure 3-1. Since this information has not yet been 

found for WSP, organ dose estimates are based on the values in ORAU 2005. Default entrance 

kerma for PA and LAT chest x-rays from ORAU 2005 are presented in Table 3-1. DCFs are listed in 

Table 3-2.

Table 3-1. Default entrance kerma by procedure and time period (ORAU 2005)

Period Entrance kerma, cGy, PA chest Entrance kerma, cGy, LAT chest

Pre-1970 0.2 0.5

1970-1985 0.1 0.25

Post-1985 0.05 0.13
Document No. ORAUT-TKBS-0028-3 Revision No. 00 Effective Date: 06/24/2005 Page 9 of 14

 

 

 

Figure 3-1. Kerma in air at 1 meter from X-ray 

source as a function of total filtration for various 

values of tube potential (from ICRP 1982).

The ICRP tables used to estimate absorbed dose (ICRP 1982) do not include all the organs included

in the Interactive RadioEpidemiological Program (IREP) computer program. For organs in IREP but 

not identified in the ICRP tables, the dose conversion coefficient that is anatomically closest to the 

IREP-specified organs can be used to estimate dose. For example, the factor for lung can be applied 

to all other organs in the thoracic cavity, such as the esophagus and bone surface. For abdominal 

organs (bladder, colon), use the dose coefficient for ovaries. Such dose assignment will be 

conservative because the analog organ is more shielded than the reference organ. Table 3-3 lists

analogs for IREP organs, as originally presented in ORAU 2005.
Document No. ORAUT-TKBS-0028-3 Revision No. 00 Effective Date: 06/24/2005 Page 10 of 14

Table 3-2. Modified ICRP dose conversion factors; absorbed dose (1 

mGy) for organs at various Al HVL for chest radiography (ORAU 

2005)(a)

.

Organ

Dose conversion factors

Pre-1970 

(2.5-mm Al 

HVL)

1970-1985

(2.5-mm Al 

HVL)

Post-1985

(4.0-mm Al 

HVL)

LAT PA LAT PA LAT PA

Thyroid 137 174 (b) 115 32 164 78

Eye/brain 137 32 115 32 164 78

Ovaries N/A N/A 0.6 1 2.5 5.2

Liver/gall bladder/

spleen

220 451 220 451 351 674

Urinary bladder N/A N/A 0.6 1 2.5 5.2

Colon/rectum N/A N/A 0.6 1 2.5 5.2

Testes N/A N/A 0.1 0.01 0.1 0.01

Lungs (male) 193 419 193 419 313 628

Lungs (female) 220 451 220 451 351 674

Thymus 220 451 220 451 351 674

Esophagus 220 451 220 451 351 674

Stomach 220 451 220 451 351 674

Bone surfaces 220 451 220 451 351 674

Remainder 220 451 220 451 351 674

Female breast 255 49 255 49 343 116

Uterus N/A N/A 0.6 1.3 2.1 5.2

Bone marrow (male) 37 92 37 92 76 178

Bone marrow (female) 29 86 29 86 59 172

Skin (c ) N/A N/A N/A N/A N/A N/A

(a) Organ doses are presented in Table 4 for all organs. (b) Per ORAU 2005, DCF for AP c-spine corrected for depth by 0.2 (c) Calculated using backscatter factor of 1.35 from NCRP Report 103, Table B-3 (ORAU 

2005); see Table 4

Table 3-3. Analogs for IREP organs not specified in ICRP (1982).

Anatomical 

location

ICRP #34 

reference organ IREP organ analogues (a)

Thoracic cavity Lung Thymus, esophagus, stomach, bone surface, liver/

gall bladder, remainder organs

Abdominal cavity Ovaries Uterus, urinary bladder, colon/rectum

Head and neck Thyroid Eye/brain

(a) ORAU 2005

3.1.4.2 Organ Dose Estimates for WSP Workers

Table 3-4 lists default organ dose estimates from LAT and PA chest x-ray examinations for each 

period (pre-1970, 1970 to 1985, and post-1985). The estimates for exposure from chest x-rays for 

these periods are taken from default values as presented in Table 5 of ORAU 2005 while site-specific 

information is being obtained. 

3.1.5

As stated in ORAU (2003 and 2005), error is defined as deviation from the correct, true, or 

conventionally accepted value of a quantity, and uncertainty is defined in terms of the potential range 

Uncertainties
Document No. ORAUT-TKBS-0028-3 Revision No. 00 Effective Date: 06/24/2005 Page 11 of 14

of a stated, measured, or assumed or otherwise determined value of a quantity. Error and uncertainty 

provide an indication of confidence in the dose estimates. Uncertainty, expressed in terms of a 

confidence level, is a more appropriate term than error, which implies that the actual value is known. 

Uncertainty, stated as a probability of falling within a stated range, includes precision and 

reproducibility of the measurement as well as accuracy (that is, how close the estimate comes to the 

actual value).

Table 3-4. Organ dose estimates for chest x-rays (rem) as presented in ORAU 2005.

[Period: Pre-1970]

Organ

Estimated dosea,b,c

HVL = 2.5 mm Al 

(uncollimated)

LAT (rem) PA (rem)

Thyroid 6.85E-02 3.48E-02

Eye/brain 6.85E-02 6.4E-03

Ovaries 1.3E-02d 2.5E-02d

Liver/gall 

bladder/spleen

1.10E-01 9.02E-02

Urinary bladder 1.3E-02d 2.5E-02d

Colon/rectum 1.3E-02d 2.5E-02d

Testes 2.5E-03d 5.00E-03d

Lungs (male) 9.65E-02 8.38E-02

Lungs (female) 1.1E-01 9.02E-02

Thymus 1.1E-01 9.02E-02

Esophagus 1.1E-01 9.02E-02

Stomach 1.1E-01 9.02E-02

Bone surfaces 1.1E-01 9.02E-02

Remainder 1.1E-01 9.02E-02

Female breast 1.28E-01 9.8E-03

Uterus 1.3E-02d 2.5E-02d

Bone marrow 

(male)

1.85E-02 1.84E-02

Bone marrow 

(female)

1.45E-02 1.72E-02

Skine 6.75E-01 2.7E-01

[Period: 1975-1985]

Organ

Estimated dosea,b,c

HVL = 2.5 mm Al 

(collimated)

LAT (rem) PA (rem)

Thyroid 2.88E-02 3.20E-03

Eye/brain 2.88E-02 3.20E-03

Ovaries 1.50E-04 1.00E-04

Liver/gall 

bladder/spleen

5.5E-02 4.5E-02

Urinary bladder 1.50E-04 1.00E-04

Colon/rectum 1.50E-04 1.00E-04

Testes 2.5E-05 1.00E-06

Lungs (male) 4.83E-02 4.19E-02

Lungs (female) 5.50E-02 4.51E-02

Thymus 5.50E-02 4.51E-02

Esophagus 5.50E-02 4.51E-02

Organ

Estimated dosea,b,c

HVL = 2.5 mm Al 

(collimated)

LAT (rem) PA (rem)

Stomach 5.50E-02 4.51E-02

Bone surfaces 5.50E-02 4.51E-02

Remainder 5.50E-02 4.51E-02

Female breast 6.38E-02 4.90E-03

Uterus 1.50E-04d 1.30E-04d

Bone marrow (male) 9.25E-03 9.20E-03

Bone marrow 

(female)

7.25E-03 8.60E-03

Skinf 3.38E-01 1.35E-01
Document No. ORAUT-TKBS-0028-3 Revision No. 00 Effective Date: 06/24/2005 Page 12 of 14

Table 3.4 (Continued). Organ dose estimates for chest xrays (rem).

[Period: post - 1985]

Organ

Estimated dose

HVL = 4.0 mm Al (collimated)

LAT (rem) PA (rem)

Thyroid 2.13E-02 3.90E-03

Eye/brain 2.13E-02 3.90E-03

Ovaries 3.25E-04 2.60E-04

Liver/gall bladder/spleen 4.56E-02 3.37E-02

Urinary bladder 3.25E-04 2.60E-04

Colon/rectum 3.25E-04 2.60E-04

Testes 1.30E-05 5.00E-07

Lungs (male) 4.07E-02 3.14E-02

Lungs (female) 4.56E-02 3.37E-02

Thymus 4.56E-02 3.37E-02

Esophagus 4.56E-02 3.37E-02

Stomach 4.56E-02 3.37E-02

Bone surfaces 4.56E-02 3.37E-02

Remainder 4.56E-02 3.37E-02

Female breast 4.46E-02 5.80E-03

Uterus 2.73E-04 2.60E-04

Bone marrow (male) 9.88E-03 8.90E-03

Bone marrow (female) 7.67E-03 8.60E-03

Skinf 1.82E-01 7.00E-02

a. SID 183 cm.

b. Image receptor size 35.6 cm by 43.2 cm.

c. Modified from Webster and Merrill (1957), as presented in ORAU 

(2005).

d. Modified from Webster and Merrill (1957) as presented in ORAU 

(2005)

e. Calculated in ORAU (2005) using backscatter factor of 1.35 from 

NCRP (1989, Table B-3).

f. Calculated in ORAU (2005) using backscatter factor of 1.40 from 

NCRP (1989, Table B-3).

Although many factors can introduce uncertainty and error into x-ray exposures, five factors contribute 

the most uncertainty to the dose estimate: measurement error, variation in applied kilovoltage, 

variation in beam current, variation in exposure time, and SSD. Film speed, the use of screens, or the 

use of grids would not affect the beam output intensity. The lack of historical records for these 

measurements for most years at WSP introduces a large uncertainty into the dose estimates that 

cannot be readily quantified, although there is no apparent reason to believe that practices at the 

Plant or its medical subcontractors were different from those at other facilities or from recommended 

standards of the medical community at the time. Therefore, the use of default estimates and reliance 

on information from other DOE sites when site-specific information was unavailable is likely to 

approximate x-ray performance at WSP closely. The following estimates of uncertainty associated 

with x-ray exposure are from ORAU (2005), which this TBD analysis relied on for default information 

in the absence of site-specific records.

ORAU (2005) reports that x-ray doses are derived largely from actual measurements of x-ray machine 

output with R-meters or similar ionization chamber devices. Reportedly, these typically had an 

uncertainty of +2% for photon energies below 400 keV, if properly calibrated and used. Although 

more current machinery could have a smaller uncertainty, +2% is assumed to be conservative.
Document No. ORAUT-TKBS-0028-3 Revision No. 00 Effective Date: 06/24/2005 Page 13 of 14

Variation in applied voltage generally falls within +5% of the machine setting. Beam intensity is 

approximately proportional to the 1.7 power of the kilovoltage, resulting in an uncertainty of 

approximately +9% in relation to beam intensity for voltages in the 110- to 120-kVp range. Variations 

in tube current are normal and generally small. As the tube current drops, beam intensity falls in 

direct proportion. Large decreases in beam output would be readily detectable and would indicate the 

need for machine maintenance or, as a temporary measure, an increase in the current or voltage to 

provide the necessary intensity for proper radiography. ORAU (2005) estimates the variation in tube 

current to be approximately + 5% for this parameter.

Exposure time can significantly affect the dose received from radiography (exposure times are a 

fraction of second). Even a small variation in exposure time due to timer error can significantly 

change beam output. Because early x-ray machine timers are known to have been inaccurate, ORAU 

(2003 and 2005) assume uncertainty in beam output due to timers to be +25%. 

SSD can contribute to variability because the entrance skin exposure is determined by this distance. 

Variations result from accuracy of positioning as well as patient size (thickness). As expressed in 

ORAU (2003 and 2005), this is generally thought to vary by no more than a few centimeters, with an 

upper limit of 7.5 cm (+10%). 

A potentially large source of uncertainty for WSP is the number and type of x-rays taken. As noted 

above, reports indicate the performance of only an annual chest x-ray examination, but no official 

protocol has been found that would rule out the possibility of other x-ray views or more frequent chest 

examinations. At this time, dose reconstructors should assume an annual chest x-ray for 1958 

through 1964.

Consistent with ORAU (2003 and 2005), the TBD analysis calculated the statistical root mean square 

to estimate total uncertainty. The root mean square is the square root of the sum of the squares of 

the individual uncertainty values, and equals 28.9%. An estimate of 30% uncertainty is larger than the 

default NIOSH guidance standard deviation recommendation of 20% (NIOSH 2002). Therefore, dose 

reconstructors should multiply all final estimates by 1.3 to account for uncertainty, conservatively 

assuming that all variables acted to increase dose.
Document No. ORAUT-TKBS-0028-3 Revision No. 00 Effective Date: 06/24/2005 Page 14 of 14

REFERENCES

ICRP (International Commission on Radiological Protection), 1982, Protection of the Patient in 

Diagnostic Radiology, Publication 34, Pergamon Press, New York, New York.

Lopez, T., 2004, “Regarding x-ray protocol for remediation workers at Weldon Spring,” Memorandum 

to file, MFG Inc., Fort Collins, Colorado, September 1.

Mallinckrodt (Mallinckrodt Chemicals Works Uranium Division), 1965, Summary of Health Protection 

Practices (revised 1965), Health/Safety Department.

Mason, M.G., 1955, Mallinckrodt Chemical Works Health Program, Policies, Status, and Summary,

February 21.

NCRP (National Council on Radiation Protection and Measurements), 1989, Medical X-ray, Electron 

Beam, and Gamma-Ray Protection for Energies Up to 50 MeV (Equipment Design, 

Performance, and Use), Report No. 102, Bethesda, Maryland.

NIOSH (National Institute for Occupational Safety and Health) 2002, External Dose Reconstruction 

Implementation Guidelines, Revision 1, OCAS-IG-001, Office of Compensation Analysis and 

Support, Cincinnati, Ohio.

ORAU (Oak Ridge Associated Universities), 2003, Technical Basis Document for the Savannah River 

Site, ORAUT-TKBS-0003, Oak Ridge, Tennessee.

ORAU (Oak Ridge Associated Universities), 2005, Technical Information Bulletin: Dose

Reconstruction from Occupationally Related Diagnostic X-ray Procedures, ORAUT-OTIB0006, Rev. 03, Oak Ridge, Tennessee. April 19.

ORAU Quigley, J. A., and M. G. Mason, 1963, Epidemiological Study of Uranium Workers –

Feasibility NLO S-512, MCW 25141-M, Report of Work Completed through the Contract 

Period. 

Thornton, W. T., and W. A. Johnson, 1965, Review of Mallinckrodt Chemical Works, October.

Webster, E. W., and O. E. Merrill, 1957, “Measurements of Gonadal Dose in Radiographic 

Examinations,” New England Journal of Medicine, 257:811-819.