ORAU Team

Dose Reconstruction Project for NIOSH

Technical Basis Document for the Idaho National Engineering 

and Environmental Laboratory (INEEL) - Occupational Medical 

Dose

 

Document Number:

ORAUT-TKBS-0007-3 

Effective Date: 01/15/2004

Revision No.: 00

Controlled Copy No.: _______

Page 1 of 11

Subject Expert: Norman Rohrig

Document Owner

Approval: _Signature on File____________ Date: 01/15/2004

Norman Rohrig, Team Leader

Approval: __Signature on File___________ Date: 01/15/2004

Judson L. Kenoyer, Task 3 Manager

Concurrence: _Signature on File________ Date: 01/15/2004

Richard E. Toohey, Project Director

Approval: __Signature on File___________ Date: 01/16/2004

James W. Neton, OCAS Health Science Administrator

Supersedes:

None

TABLE OF CONTENTS

Record of Issue/Revisions ...................................................................................................................2

Acronyms and Abbreviations ...............................................................................................................3

3.1 Introduction................................................................................................................................. 4

3.2 Examination Frequencies............................................................................................................4

3.3 Equipment and Techniques ........................................................................................................5

3.4 Organ Doses...............................................................................................................................6

3.5 Uncertainty..................................................................................................................................6

References ..........................................................................................................................................8

Glossary ..............................................................................................................................................9

ATTACHMENT 3A OCCUPATIONAL MEDICAL DOSE ................................................................. 10
Effective Date: 01/15/2004 Revision No. 00 Document No. ORAUT-TKBS-0007-3 Page 2 of 11

Record of Issue/Revisions

ISSUE

AUTHORIZATION

DATE

EFFECTIVE 

DATE

REV.

NO.

DESCRIPTION

Draft 08/31/2003 00-A New Technical Basis Document for the Idaho 

National Engineering and Environmental Laboratory 

(INEEL) - Occupational Medical Dose. Initiated by 

Norman Rohrig.

Draft 09/23/2003 00-B Incorporates changes in response to NIOSH and 

ORAU comments. Initiated by Norman Rohrig.

Draft 11/12/2003 00-C Incorporates additional changes in response to 

NIOSH and ORAU comments. Initiated by Norman 

Rohrig.

Draft 11/26/2003 00-D Incorporates changes in response to DOL

comments. Initiated by Norman Rohrig.

1/15/2004 01/15/2004 00 First approved issue. Initiated by Norman Rohrig.
Effective Date: 01/15/2004 Revision No. 00 Document No. ORAUT-TKBS-0007-3 Page 3 of 11

ACRONYMS AND ABBREVIATIONS

AEC U.S. Atomic Energy Commission

AP Anterior-Posterior

cm centimeter

EEOICPA Energy Employees Occupational Illness Compensation Program Act

ICRP International Commission on Radiological Protection

INEEL Idaho National Engineering and Environmental Laboratory

IREP Interactive RadioEpidemiological Program

KERMA Kinetic Energy Released to Matter

kg kilogram 

kV kilovolt

kVp kilovolt peak

lat lateral

lb pound

mA milliampere

mm millimeter

mrad millirad

msec millisecond

PA Posterior-Anterior 
Effective Date: 01/15/2004 Revision No. 00 Document No. ORAUT-TKBS-0007-3 Page 4 of 11

3.1 INTRODUCTION

This section discusses the occupational medical dose workers received during employment at INEEL 

(Idaho National Engineering and Environmental Laboratory). The site required preemployment and 

periodic physical examinations as part of its occupational health and safety program. At first, the 

Atomic Energy Commission (AEC) provided these medical examinations for all contractors and AEC 

personnel. Later, the service became the responsibility of the site prime contractor. 

The examinations typically included diagnostic chest X-rays. The dose from these procedures 

depended not only on the characteristics of the X-ray machine and the procedure used, but also on 

the frequency of examinations. This section discusses the various X-ray techniques and equipment 

used over the years at the INEEL. Attachment 3A contains tables for use by dose reconstructors in 

determining a worker’s occupational medical dose. The primary source of information on medical 

X-rays is a report by Collings and Creighton (2002) prepared at National Institute for Occupational 

Safety and Health EEOICPA request.

3.2 EXAMINATION FREQUENCIES

Collings and Creighton (2002) reported that from 1954 to 1970 chest X-rays were performed on new 

hires and on radiation workers at ages 25, 30, 34, 37, and 40, every 2 years from ages 40 to 62, and

then every year. They also reported that all employees went on this schedule in 1970. A somewhat 

contradictory schedule is reported in the 1960 Annual Report (AEC 1961) as noted in the following 

table:

Age

Radiation area employees

Badged

Nonradiation employees

Nonbadged

18-24 4 years At age 30

25-39 3 years 5 years

40-49 2 years 3 years

50-59 1 year 2 years

Over 60 1 year 1 year

This schedule is corroborated by a John Sommers memorandum (Sommers 1961). We assume that 

the 1960 schedule applies to dose reconstruction for all workers in the 1954 to 1970 period because it 

involved more examinations and is thus claimant-favorable.

The Appendix to AEC Manual Chapter 0528 (AEC 1969) specified the following:

• A chest X-ray would be part of a medical examination.

• Workers under 40 would receive an exam at a frequency influenced by several factors.

• Workers over 40 would receive an exam at least every 2 years (approximately annually when 

indicated).

The schedule in the table is consistent with that requirement except for ages 40 to 49. The 1971 

Annual Report (AEC 1972) states the schedule for examinations is “at time of hire, at ages 25, 30, 34, 

37, and 40, every two years until age 62 and then annually.” This is identical to that reported by 

Collings and Creighton (2002) and is assumed to apply from 1970 to 1976. 
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Beginning in 1976, physicals occurred every 2 years for workers under age 45 and every year for 

those over age 45 (Collings and Creighton 2002). On February 1, 1978, routine chest X-rays were 

eliminated on periodic physicals except for high-risk (as determined by the physician) individuals, in 

which case they were performed every 4 years. Records from the exposures are reported in each 

worker’s medical file. 

3.3 EQUIPMENT AND TECHNIQUES

The standard distance from source to image was 72 inches (183 cm).

To the best of our knowledge, none of the INEEL exams used fluoroscopic techniques (Creighton 

2003; Spickard 2003). In the 1971 Annual Report, a medical van is identified as taking 22% of the 

4,426 X-ray examinations. Also mentioned is the Idaho Falls Navy dispensary for doing X-ray 

examinations. Both of these facilities performed standard chest X-rays (Spickard 2003) and did not 

do photoflouroscopy. A key word search of the INEEL records system using the words collimation, 

fluoroscopic, Health and Safety, Health and Safety Services, Medical X-ray, photofluorography, and 

x-ray resulted in nothing indicating use of fluoroscopic techniques (Vivian and Rockhold 2003).

From 1954 to February 1990, X-ray examinations were performed with a single-phase General 

Electric Model DXD350 machine. The voltage was 90 kVp, the current was 300 mA, and the duration 

of the exposure was 1/15 sec (67 msec). Added filtration of 2 mm aluminum was used, and a 10:1 

grid was used to reduce scatter radiation (Collings and Creighton 2002). Tube window thickness is 

assumed to be about 0.5 mm. Based on Table A16 of Protection of the Patient in Diagnostic 

Radiology (International Commission on Radiological Protection Publication 34; ICRP 1982), the 

half-value layer at 90 kVp and 2.5 mm total aluminum filtration is 2.58 mm Al.

From February 1990 to the present, X-rays have been performed with a three-phase Gendex Model 

110-0030G2. The voltage was 100 kVp, the current was 300 mA, and the duration was 32 msec. 

Added filtration of 2 mm aluminum was used, and a 10:1 grid was used to reduce scatter radiation

(Collings and Creighton 2002). Tube window thickness is assumed to be about 0.5 mm. Based on 

Table A17 of ICRP (1982), the half-value layer at 100 kVp and 2.5 mm total aluminum filtration is 3.3

mm Al.

Practices before 1954 are unclear. Offsite facilities might have been contracted to perform the 

examinations. The default value for entrance kerma of 200 mrad (Kathren 2003) is assumed for that 

period. 

From 1954 to 1970, the chest X-ray consisted of a single posterior-anterior (PA; back to front) image. 

From 1970 to 1978, the procedure consisted of both PA and lateral views. From 1978 to 1990, the

lateral view was dropped and only a PA view was made. For the latest period from 1990 to the 

present, there was both PA and lateral views. For lateral views, the exposure time was about 1.25 

times that of the PA view. In Collings and Creighton (2002), the terms PA and AP (anterior-posterior, 

front to back) appear somewhat interchangeably. Creighton attributed this presumed interchangeable 

usage to a typographical error. The August 21, 1975, Energy Research and Development 

Administration requirement for occupational medical programs (replaced in 1982) specified the 

minimum requirements for chest X-rays and specified a PA view at least once every 5 years, as well 

as when transferring to a job with cardiorespiratory system stress (ERDA 1975).

Collimation and control of scatter for the INEEL facilities generally followed the state of the medical art

as it improved. However, in absence of particular information about collimation, we will use the dose 

conversion factors in Table 4.0-1 of Kathren (2003) for the pre-1970 time frame. 
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3.4 ORGAN DOSES 

The entrance air kerma for 100 mA sec can be determined from Table B3 of National Council on 

Radiation Protection and Measurements Report No. 102 (NCRP 1989) and the beam voltage, 

distance, and total filtration. Tables A2 to A9 of ICRP (1982) list Monte Carlo calculation results of the 

ratio of organ doses to air kerma, for a 70-kg (154-lb) male or female, for the thyroid, ovaries, testes, 

lungs, female breast, uterus (embryo), active bone marrow, and total body under different exposure 

conditions. For organs where there is a difference for males and females, the larger value is used to 

be claimant favorable. A linear interpolation, applicable to the pre-1990 and post-1990 years, was 

used between the dose ratios for half-value layers of 2.5, 3.0 and 3.5 mm Al to the values of 2.58 and 

3.3 mm Al. The skin entrance surface was assumed to be 30 cm from the film for the PA view and 40 

cm from the film for the lateral view. These distances account for body thickness and any other space 

between the person and the film. The dose to the skin is the product of the entrance skin exposure 

and a backscatter factor taken from NCRP 102 Table B-8.

The organ dose from a PA image is the product of the two table values, an inverse square correction, 

and the product of exposure current and time. Table 3A-1 lists these values. For lateral images, a 

similar calculation was performed and added to the PA result. 

Under the Energy Employees Occupational Illness Compensation Program Act (EEOICPA) of 2000 

(Public Law 106-398), cancers in several other organs are compensable, as listed in the Interactive 

RadioEpidemiological Program (IREP). The ratio of doses for two organs is affected by the relative 

atomic numbers of the tissue (bone dose is higher than dose in nearby muscle), the relative positions 

of the organ and the X-ray beam, and the depth in the body. Attachment 3A lists these other organs 

and the organs from ICRP (1982), which were used to estimate the dose. Table 3A-1 features these 

organs in the third row.

3.5 UNCERTAINTY

Uncertainties in the occupational medical dose result from uncertainties in the current, voltage, and 

time for the exposures. The organ doses are also influenced by the size of the person. For IREP 

organs where an analog organ is used from the ICRP (1982) organs, the IREP organs are generally 

deeper in the body so the dose will be lower than the analog organ. No estimate is made of this onesided uncertainty because it cannot lead to a larger dose.

The uncertainties assigned in the Savannah River Site Technical Basis Document (ORAU 2003) are 

generically valid for X-ray programs. The uncertainty at one sigma due to voltage was 9 percent, that 

due to current was 5 percent, and that due to time was 25 percent. The uncertainty for voltage 

assumes a 5% voltage uncertainty and since the output has a V1.7 dependence results in a 9 %

uncertainty. Output is directly proportional to current which is assumed to have a 5 % uncertainty. 

The usually unfiltered voltage output from the voltage rectifier cause a pulsed character to the x-ray 

output at 120 Hz (twice the supply frequency). For the short exposure times this results in only a few 

pulses and thus a fairly large uncertainty due to time.

All Monte Carlo calculations have an uncertainty determined by the length of the run and the number 

of events scored for each calculation. For the organ dose calculations from ICRP 34, this uncertainty 

was not stated. Based on judgment, it is assumed to be 5% at 1 sigma which would require at least 

400 counts in each scoring unit. 

The error due to patient thickness has two causes: (1) an increase for a larger person being closer to 

the source and (2) a decrease due to additional attenuation in the body. The Monte Carlo calculations 
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in ICRP (1982) assumed 70-kg (154-lb) male and female geometries. The 10% uncertainty assigned 

in the Savannah River Site Technical Basis Document was due to the first cause; but, because the 

effects counteract, that value is appropriate for the combined effect. This should be taken as 1 sigma 

on a normal distribution. These sources of uncertainty added in quadrature result in a combined 

uncertainty of ±30 % at 1 sigma or 84% confidence.
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REFERENCES

AEC (U.S. Atomic Energy Commission), 1961, Annual Report of the Health and Safety Division,

Report No. IDO-12019, Idaho Operations Office (IDO), 1960, Idaho Falls, Idaho

AEC (U.S. Atomic Energy Commission), 1969, AEC Manual Chapter 0528, Appendix, Occupational 

Health Program, December 5, 1969.

AEC (U.S. Atomic Energy Commission), 1972, 1971 Annual Report of the Health Services Laboratory,

Report No. IDO-12076, Idaho Operations Office (IDO), Idaho Falls, Idaho

Collings, L. H. and Creighton, P., 2002, Idaho National Engineering and Environmental Laboratory 

(INEEL) History of the Occupational Medical Program (OMP) X-Ray Process, April 8, 2002.

Creighton, P. N., 2003, “Transmittal of Medical X-ray Information for the INEEL,” letter to L. Johnson 

(Intrepid Technology and Resources), Idaho National Engineering and Environmental 

Laboratory, Idaho Falls, ID, June 24, 2003.

ERDA (Energy Research and Development Administration), 1975, ERDA Manual Appendix 0528-A, 

Contractor Occupational Medical Program Handbook, August 21, 1975.

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

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

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.

Kathren, R. L. (2003),Technical Information Bulletin: Dose Reconstruction from Occupationally 

Related Diagnostic X-Ray Projections, ORAU-OTIB-0006, Rev.00 of 11/14/2003.

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

Site to be Used for EEOICPA Dose Reconstructions. ORAU Team Dose Reconstruction 

Project for National Institute for Occupational Safety and Health, Rev. 0, Oak Ridge, 

Tennessee, July 15, 2003.

Public Law 106-398, Energy Employees Occupational Illness Compensation Program Act of 2000

(42 U.S.C. Section 7384 et seq.) 

Sommers, J. F., 1961, memorandum, “Routine Blood Sampling Program at the MTR-ETR,” 

Som-165-61A-M, December 15, 1961. 

Spickard, J. (Physician and Medical Director at INEEL 1960-1988), Phone conversation of 11/12/03 

with Norman Rohrig.

Vivian, K. A.(DOE-ID) and Rockhold, L. E. (BBWI) 2003, Transmittal of Medical Documents from the 

INEEL, Letter of November 18, 2003 to Norman Rohrig (Intrepid).
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GLOSSARY

Atomic Energy Commission

Original agency established for nuclear weapons and power production; a predecessor 

to the U.S. Department of Energy.

Anterior-Posterior

Irradiation geometry in which the radiation passes from the front of a person to the 

back.

Lateral 

Irradiation geometry in which the radiation passes from one side of a person to the 

other.

Posterior-Anterior 

Irradiation geometry in which the radiation passes from the back of a person to the 

front.

rad

The unit for absorbed dose, 1 rad = 100 erg gm-1

X-ray 

Ionizing electromagnetic radiation of external nuclear origin or an image generated by 

exposing a detector (e.g., film) to x-rays.
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ATTACHMENT 3A OCCUPATIONAL MEDICAL DOSE

The following are analogs for IREP organs not included in ICRP (1982):

Anatomical 

Location

ICRP (1982) Reference Organ IREP Organ Analogs

Head Thyroid Eye

Brain

Thorax Lung Thymus

Esophagus

Bone surface 

Stomach

Liver/Gall Bladder

Abdomen Ovaries Urinary Bladder

Colon

Uterus

INEEL conducted initial and periodic X-ray examinations as part of the medical examinations. The 

skin entrance air KERMA values in mrad are shown below.

Air kerma (mrad) PA Lat

Pre 1954 200 200

1954 to 1990 52 74

1990 to present 53 76

Table 3A-1 lists the frequencies and doses. Table row 2 lists the organs identified in ICRP (1982) and 

table row 3 lists the organs identified in IREP that are not listed in ICRP (1982). The uncertainties at 

the 84% confidence limit (1 sigma) are ±30 %. 
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Table 3A-1. Organ doses from occupational medical exposures at the INEEL.

ORGAN DOSES (mrad) from INEEL Chest X-Ray

ICRP 34 Organs Thyroid Testes Lungs Breast

Ovary

Embryo

Bone 

Marrow 

Other Organs

Eye 

Brain

Thymus 

Esophagus 

Stomach

Bone Surface

Liver

Gall Bladder

Uterus 

Bladder 

Colon Skin

Time 

Period Frequency Geometry

Before 

1954 

No information PA 69 1.8 93 10 34 19 272

Assume annual

1954 to 

1969

New hires PA 18 0.5 24 2.7 8 5 70

Radworkers

Every 4 yr 18-24

 Triennial 25-39

 Biennial 40 - 49

Annual over 50

Non radworkers

Every 5 yr 30-39

Triennial 40-49 

Biennial 50-59

Annual over 60

1970 to 

1976

 

New hires PA, 

Lat

10 0.008 41 22 0.1 8 171

25, 30, 34, 

37, 40

Biennial 40 to 62

Annual >62

1976 to 

1978

New hires PA,

Lat 

Biennial <45

Annual >45

1978 to 

1990 

New hires PA 1.8 0.001 24 2.7 0.1 5.0 70

4 years High risk 

1990 to only PA, 

Lat

14 0.008 53 27 0.3 11 180

present