ORAU Team

NIOSH Dose Reconstruction Project

Technical Basis Document for the Fernald Environmental 

Management Project – Occupational Medical Dose

Document Number:

ORAUT-TKBS-0017-3 

Effective Date:02/11/2004

Revision No.:00

Controlled Copy No.: ______

Page 1 of 26

Subject Expert: Melton H. Chew

Document Owner

Approval: Signature on File Date: 02/13/2004

Terry A. Kuykendall, TBD Team Leader

Approval: Signature on File Date: 02/18/2004

Judson L. Kenoyer, Task 3 Manager

Concurrence: Signature on File Date: 02/18/2004 Richard E. Toohey, Project Director

Approval: _Signature on File ____________Date: 02/19/2004 James W. Neton, OCAS Health Science Administrator

Supersedes:

None

TABLE OF CONTENTS

Section

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

Page

3

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

3.0 Occupational Medical Dose ........................................................................................................5

3.1 Introduction................................................................................................................................. 6

3.1.1 Applied Kilovoltage and Filtration .......................................................................................6

3.1.2 Current and Exposure Time ...............................................................................................8

3.1.3 Distance .............................................................................................................................8

3.1.4 Collimation and Waveform Characteristics ......................................................................... 9

3.1.5 Screens, Grids, and Other Factors with the Potential to Affect Work Dose......................... 9

3.1.6 Assumptions for Dose Conversion ................................................................................... 10

3.2 Examination Frequencies.......................................................................................................... 11

3.3 Equipment and Techniques ...................................................................................................... 11

3.4 Organ Dose Calculations .......................................................................................................... 15

3.5 Uncertainty................................................................................................................................16

References ........................................................................................................................................24

Glossary ............................................................................................................................................26
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LIST OF TABLES

Table

3-1 Relationship of beam intensity and various technical factors....................................................

Page

8

3-2 Frequency of occupational chest X-rays at FEMP.................................................................. 11

3-3 Description of FEMP X-ray equipment ................................................................................... 12

3-4 1961 survey of X-ray units...................................................................................................... 12

3-5 X-ray conditions and power used ........................................................................................... 13

3-6 Calculated and measured results of entrance skin exposure and comparison 

with proposed guides ............................................................................................................. 13

3-7 X-ray techniques (issue date 7/23/87).................................................................................... 14

3-8 Measured entrance skin exposures........................................................................................ 14

3-9 Analogues for IREP organs not in ICRP 34............................................................................ 15

3-10 Summary of beam parameters for 14" × 17" PA chest radiography........................................ 18

3-11 Average absorbed chest X-ray dose (mGy) for selected organs for 1 Gy 

entrance kerma (air kerma without backscatter) for a beam quality of 2.5 mm 

aluminum (HVL).....................................................................................................................19

3-12 Average absorbed chest X-ray dose (mGy) for selected organs for 1 Gy 

entrance kerma (air kerma without backscatter) for a beam quality of 3.0 mm 

of aluminum (HVL) ................................................................................................................. 19

3-13 Organ dose estimates for FEMP chest radiographs from 10/1951 to 1/1977.......................... 20

3-14 Organ dose estimates for FEMP chest radiographs from 2/1977 to 2/1988............................ 20

3-15 Organ dose estimates for FEMP chest radiographs from 3/1988 to 1/1991............................ 21

3-16 Organ dose estimates for FMPC chest radiographs from 2/1991 to 4/1993 ........................... 21

3-17 Organ dose estimates for FMPC chest radiographs from 5/1993 to 3/1995 ........................... 22

3-18 Organ dose estimates for FMPC chest radiographs from 4/1995 to 6/1999 ........................... 22

3-19 Organ dose estimates for FMPC chest radiographs from 7/1999 to present........................... 23
Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 3 of 26

RECORD OF ISSUE/REVISIONS

ISSUE 

AUTHORIZATION 

DATE

EFFECTIVE 

DATE

REV. 

NO. DESCRIPTION

Draft 10/31/2003 00-A New Technical Basis Document for the Fernald 

Environmental Management Project – 

Occupational Medical Dose. Initiated by Terry 

Kuykendall.

Draft 12/23/2003 00-B Incorporates NIOSH and internal review 

comments. Initiated by Terry Kuykendall.

Draft 01/27/2004 00-C Incorporates additional NIOSH review comments. 

Initiated by Terry Kuykendall.

Draft 02/11/2004 00-D Corrects Lung dose (male) value in Table 3-17, 

per NIOSH request. Initiated by Terry Kuykendall.

02/11/2004 02/11/2004 00 First approved issue. Initiated by Terry 

Kuykendall.
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ACRONYMS AND ABBREVIATIONS

AEC automatic exposure control 

Al aluminum

AP anterior-posterior

DHHS State of Ohio Department of Human and Health Services

DOE U.S. Department of Energy

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

ESE entrance skin exposure

FEMP Fernald Environmental Management Project

FERMCO Fernald Environmental Restoration Management Corporation

FMPC Feed Material Production Center

Gy gray 

HVL half value layer

ICRP International Commission on Radiological Protection

ICRU International Committee for Radiological Units

IREP Interactive RadioEpidemiological Program

kVp kilovolt peak

LAT lateral

mA milliampere

mAs milliampere-sec

NBS National Bureau of Standards

NCRP National Council on Radiation Protection

NIOSH National Institute for Occupational Safety and Health

OD optical density

PA posterior-anterior

RMS root-mean-square

SID source-to-image distance

SOP Standard Operating Procedure

SSD source-to-skin distance

TBD technical basis document
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3.0

This section provides the technical basis for estimation of Fernald site worker radiological dose from 

exposure to occupational medical radiation sources.

OCCUPATIONAL MEDICAL DOSE

The following criteria are applicable for the National Institute for Occupational Safety and Health 

(NIOSH) dose reconstruction program and this Technical Basis Document (TBD):

Only exposure to X-rays that were performed as a condition of employment is included; X-rays that 

resulted from injuries or medical testing are not included.

Medical exposures are assigned or assumed based on the actual or calculated frequency of chest Xrays required for employment.

There is no difference between the exposures experienced by unmonitored versus monitored workers 

since dosimeters normally worn by workers were not worn during diagnostic medical X-ray 

examinations. All exposures are external based on the assumption that internal radioisotopes were 

not administered for diagnostic purposes (with the exception that some radioisotopes might have 

been used at specific sites for stress testing as part of working conditions).

Specific organ doses to be attributed for posterior-anterior (PA) chest X-rays should be calculated on 

the basis of the dose conversion factors found in International Commission on Radiological Protection 

(ICRP) Publication 34 (ICRP 1982).

Organ doses from lateral chest radiography should be estimated at 2.5 times greater than those from 

the corresponding PA doses, based primarily on the greater mAs exposure per radiograph and the 

somewhat smaller source-to-skin distance (SSD). If technique factors can be identified for Type I 

equipment, organ doses for Type I equipment may be calculated by multiplying the organ dose 

estimates for Type II equipment by 2.5. This approach is reasonable when compared to other U.S. 

Department of Energy (DOE) sites (e.g., Hanford) where more information on X-ray equipment from 

the early period is available.

For organs not listed in ICRP (ICRP 1982) but specified in the Interactive RadioEpidemiological 

Program (IREP) code, doses should be determined by analogy with anatomical location. Using this 

logic, IREP code organs in the thoracic cavity that are not mentioned in ICRP (ibid) can be assigned 

the same dose as the lungs; doses to organs in the head and neck can be assigned the same dose 

as the thyroid. Head and neck organ (i.e., eye and brain) dose estimates should be somewhat 

greater than doses actually incurred (and therefore are claimant-favorable) because of geometry 

considerations and, at least in the case of the brain, because of attenuation by the bony cranium. To 

ensure claimant-favorability in view of the variations in organ dose described in ICRP (ibid, p. 51), 

apply the dose values for females, which are slightly higher than those for males.

For both PA and lateral views, a standard source-to-image distance (SID) of 72 inches (183 cm) may 

be assumed unless specifically noted otherwise.

If not specified, assume that all X-ray machines were single-phase and that there was no air gap 

between the patient and the film.

If there is an indication that mobile X-ray units were used, this could result in higher doses. This would 

imply that this type of unit (which could have been a photofluorographic machine) might have 

delivered higher exposures.
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3.1 INTRODUCTION

The Fernald Environmental Management Project (FEMP, formerly known as the Feed Material 

Production Center, or FMPC) required pre-employment examinations and offered annual physical 

examinations as part of its occupational health and safety program. These medical examinations 

typically included diagnostic chest X-rays. Doses from these examinations depended not only on the 

characteristics of the X-ray machine and the procedure used, but also on the frequency of the 

examinations. The Energy Employees Occupational Illness Compensation Program Act of 2000 

(EEOICPA) recognized that diagnostic medical X-rays administered in conjunction with routine or 

special physical examinations required for employment are a valid source of occupational exposure. 

This document describes the technical factors for and aspects of dose reconstruction from medical 

X-rays.

A number of factors determine doses to workers from diagnostic X-ray examinations. For a relatively 

standard medical radiographic (i.e., diagnostic) unit with a tungsten target (anode) and a focal spot of 

1 to 2 mm, these factors involve the basic machine settings used for the exposure, which include the 

applied kilovoltage of the beam (kVp), beam current (mA), time of exposure, distance, waveform, 

amount and kind of filtration used, collimation or use of diaphragms, tube housing characteristics, type 

and speed of the film, development procedure, screens, grids, and the size of the worker. 

3.1.1

The energy of the X-ray beam is determined by the applied kilovoltage and the filtration, and is 

sometimes referred to as beam quality. X-rays produced in a typical medical X-ray tube are 

bremsstrahlung photons and, as such, are represented by a distribution or spectrum of energies 

ranging from zero to the applied kilovoltage (which refers to the potential between the anode and 

cathode of the tube). For a typical unfiltered X-ray spectrum, the average energy is approximately 

one-third of the peak energy, or applied kilovoltage. Therefore, most X-rays produced are much lower 

in energy than the applied kilovoltage of the beam, and are attenuated by the torso or other portion of 

the body being radiographed and never reach the film. These X-rays add very little to the radiography 

process, but contribute significantly to worker dose.

Applied Kilovoltage and Filtration

To reduce the dose to the worker, filtration in the form of a specified thickness of absorbing material is 

added in front of the X-ray beam. This has the net effect of absorbing a large fraction of the lower 

energy X-rays that are of little or no value in producing the radiograph while allowing most of the more 

energetic and radiographically useful X-ray photons to pass. In this manner the dose to the worker is 

reduced significantly and radiographic quality can be enhanced. A filtered X-ray spectrum has a 

correspondingly higher average energy than an unfiltered spectrum, although the photon fluence rate 

is significantly reduced. Such a beam is typically referenced as having been hardened. A variation of 

this filtration technique is to use a higher applied kilovoltage and to filter the beam (relatively) heavily 

to eliminate most of the low-energy photons, which are of little radiographic value, from reaching the 

worker.

Beam energy is specified in terms of quality, or hardness, which in turn can be expressed in terms of 

the half value layer (HVL) in aluminum. Unfortunately, available documentation rarely presents this 

parameter. Even if the HVL is known, it might be of limited value in part because it does not specify 

the maximum energy of the beam or its true quality. This is because as the HVL measurement is 

made, the absorbers act as filters and the beam is further hardened. Therefore, the first HVL is 

always smaller than the second, which in turn is smaller than the third, and so forth. What are 

commonly (although not always) available are the kVp of the machine and the external or added 

filtration. All X-ray tubes have “inherent” filtration, which is attributed to the window or port of the tube. 
Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 7 of 26

In medical diagnostic X-ray units, the window is thin (typically equivalent to 0.5 mm of aluminum in 

attenuation) and therefore provides little beam hardening.

Although the benefits of filtration for improved radiographic images were known and understood as 

early as March 1896 (within months of the discovery of X-rays), diagnostic radiographs were initially 

constructed with no added filtration. In 1937 the International Committee for Radiological Units 

(ICRU) recommended (although not specifically for thickness) aluminum filters for X-rays of 20 to 

120 kVp, which includes the diagnostic X-ray energy range (ICRU 1937). Typical external filtration in 

the 1940s ranged from none to 1 mm of aluminum. This practice was in accordance with the 1936 

recommendations of the U.S. Advisory Committee on X-Ray and Radium Protection (which became 

the National Council on Radiation Protection, or NCRP) that called for 0.5 mm of aluminum equivalent 

for radiographic installations and 1 mm of aluminum for fluoroscopy (NBS 1936). In 1949 the NCRP 

recommended 1 mm of aluminum filtration for radiography of thick parts of the body such as the chest 

(NBS1949). This filtration thickness was used in 100-mA units in large military hospitals during World 

War II, and presumably was applied to similar units at some DOE sites. In later applications the 

recommended filtration thicknesses were increased; in 1955, the NCRP guidance on diagnostic X-ray 

units recommended 2 mm of total aluminum filtration for new machines (NBS 1955). This increased 

in 1968 to 2.5 mm for medical diagnostic units operating above 70 kVp (NCRP 1968). Based on 

documentation of early measurements (November 20, 1961), FEMP used 2.5 mm of aluminum for the 

original X-ray unit since the start of operations. 

The relationship of beam intensity1

The approximate intensity reduction afforded by any thickness of aluminum filtration can be 

determined by the following exponential equation:

to applied kVp and filtration is complex and to some extent 

machine-specific and, therefore, is best determined empirically. However, in the absence of empirical 

data for a specific machine, there are adequate contemporary empirical and theoretical data on which 

to estimate machine output within a reasonable degree of uncertainty. Additional filtration reduces the 

entrance skin exposure (ESE), generally in an exponential manner. For a typical single-phase, half-, 

full-, or self-rectified machine operating in the diagnostic range of 80 to 100 kVp, each additional 

millimeter of aluminum filtration will effect a reduction of approximately 40% in the ESE (Trout, Kelley, 

and Cathey 1952; Taylor 1957). 

I = Ioe-0.5t (3–1)

or

ln (I/Io) = -0.5 t (3–2)

where t is the thickness of aluminum in millimeters, and I and Io are the beam intensities with and 

without the filter, respectively. In the absence of specific measurements or empirical data, this 

correction can be applied to determine the effect of filtration on beam intensity, and is consistent with 

the guidance in External Dose Reconstruction Implementation Guideline (NIOSH 2002).

Table 3-1 indicates the relationship of X-ray beam intensity and various technical factors.

Similarly, increasing the kVp will increase the beam intensity or exposure rate. This relationship can 

be calculated, but such calculations are difficult, complex, and time-consuming (even with the use of 

computer programs), and are at best approximations. However, many empirical studies of beam 

 

1. As used here, the term beam intensity refers to the output of the machine in terms of exposure in the special sense per 

mAs. Exposure in the special sense is referenced to ionization in air and, as such, is not a dose quantity.
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Table 3-1. Relationship of beam intensity and various technical factors. 

Parameter Units Relationship with intensity

Applied voltage kVp Intensity proportional to 1.7 power of kVp

Tube current mA Linear

Exposure time s Linear

Filtration mm Al Intensity decreases by ~40% for each additional mm Al

Worker size

(chest thickness) 

25-27 mm

> 27 mm

Dose increased by factor of 1.5

Dose increased by factor of 2

Distance d Approximately inverse square relations (1/d2)

Uncertainty + 30 % Assume all errors are positive, + 30% should be used

intensity as a function of kVp provide ample credible evidence to show that, for a given amount of 

filtration, increasing the applied kVp will increase the beam intensity according to the 1.7 power of the 

applied kilovoltage (Handloser 1951; Trout, Kelley, and Cathey 1952; Kathren 1965; BRH 1970). In 

the absence of specific measurements or empirical data, this function can be applied to determine the 

effect of applied kilovoltage on beam intensity, and is fully consistent with the NIOSH guidance 

(NIOSH 2002).

3.1.2

Diagnostic X-ray exposures typically are specified in terms of milliampere-seconds (mAs; the product 

of X-ray tube current and exposure time). All factors being equal (e.g., kVp, filtration, film, 

development and screen combination), radiation exposure is proportional to the number of mAs. The 

current in an X-ray tube refers to the number of electrons accelerated across the evacuated volume of 

the tube, flowing from the cathode to the anode. For a given applied kilovoltage, the number of X-ray 

photons produced and therefore the exposure (at least in theory) will be directly proportional to the 

X-ray tube current. This is and has been true for most medical radiography units over their design 

tube current range. Data from beam measurements conducted with medical radiographic X-ray units 

at FEMP are indicative of this linearity.

Current and Exposure Time

Exposure time refers to the time the beam was on or the machine was producing X-rays and is, for all 

practical purposes, linear with exposure. To avoid or minimize image blurring from the beating heart, 

exposure time for chest radiography was minimized, and the current was increased proportionally to 

obtain the desired exposure in terms of mAs. From a dose reconstruction standpoint, earlier medical 

radiographic units had mechanical timers that were not as accurate as the electronic timers on later 

units. Gross bias errors in timer accuracy are unlikely because they would result in over- or 

underexposure of the radiograph and therefore would be quickly detected and corrected. Small 

random errors, which might produce uncertainties of as much as ±20% in the exposure, are more 

subtle. However, measurement data from the FEMP medical X-ray units give no indication or 

suggestion that the time or exposure parameters might be subject to a significant degree of error. 

3.1.3

X-ray beam intensity is a function of distance from the target, approximating the inverse square at 

large distances from the tube. Radiographic chest films were taken at a standard source to image 

distance (SID) of 72 inches; source refers to the focal spot of the tube and image to the plane of the 

film. The distance to the worker, who was between the source and the film cassette, sometimes 

expressed in terms of the SSD, was smaller. Therefore, the ESE to the worker was somewhat 

greater than the exposure at the plane of the film. In addition, patient attenuation would further 

reduce or attenuate the number of photons reaching the film. To compensate for the increased 

attenuation provided by a larger worker, X-ray technicians would sometimes increase the beam 

Distance
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settings or, if the machine was so equipped, might use a high-speed Bucky diaphragm, probably with 

a somewhat higher kVp. Based on this information, it might be appropriate for an individual dose 

reconstruction to increase the ESE for a large or stout worker.

3.1.4

Among other factors that could affect worker dose are collimation and waveform. X-ray waveforms 

are of three types: half-wave rectified, which is rare; full-wave rectified, which is typical of medical 

radiographic units (and characteristic of units used at some DOE sites); and constant potential. A 

half-wave rectified machine produces 60 half-sinusoidal-shaped pulses of X-rays per second, each 

with duration of 1/120 of a second. A full-wave rectified machine produces 120 half-sinusoidal pulses 

per second, each with duration of 1/120 of a second. Therefore, for a given setting of kVp and mA, 

the intensity of the beam from a half-wave rectified machine is half that of the beam from a full-wave 

rectified unit. A constant potential machine produces a more or less steady (i.e., unpulsed) output of 

X-rays and has greater beam intensity (approximately 10% greater) compared to a full-wave rectified 

machine operating at the same kVp and mA. For FEMP, waveform is of no significance for 

determination of worker exposure because actual output measurement data are available.

Collimation and Waveform Characteristics

Collimation refers to the size of beam. The early philosophy for radiography was to use a fairly large 

aperture with limited collimation to ensure that the entire area of interest was included in the 

radiograph. Later, because of health protection concerns, beams were collimated such that the 

smallest beam consistent with the area of interest was used, thereby limiting the area of the patient 

exposed and, in the case of chest radiography, minimizing dose to organs such as gonads, thyroid, 

and gastrointestinal tract. A practical check of collimation can be conducted by examination of the 

radiograph. 

On November 26, 2003, a telecommunications discussion was conducted with the current FEMP 

records manager, Mr. Brian Devir, who (as a request of the TBD investigation) selectively examined 

radiographs from chest X-rays taken from 1952 to 1980. He confirmed that a clearly distinct darkened 

area existed at the lower edge of each radiograph, which is specifically indicative of the use of 

collimation. Also noted was that all of the radiographs examined from the years 1952 to 1980 

exhibited the same unexposed area at the edges. A well-collimated beam would have left a small, 

unexposed area or penumbra effect at the edges of the radiograph, while a poorly collimated beam 

would have produced a radiograph that was exposed over the entire area. Based on the discussions 

with Mr. Devir and the correlated evaluation of the radiograph files, it is possible to reach the 

conclusion that the X-ray beams used at FEMP were collimated from the beginning of the medical Xray processes at the site, and should be treated as such when estimating the contribution of an 

individual due to medical X-ray exposure.

3.1.5

A number of other factors affect the X-ray exposure required to obtain a proper radiograph and the 

attendant dose to the worker. Knowledge of these factors is unnecessary for dose reconstruction 

purposes if actual beam measurements are available, or if the primary machine characteristics of 

applied voltage, time, current, and amount of primary beam filtration are known. However, these 

other factors, which include housing, type and speed of film, development procedure, screens, and 

grids, can be used as additional confirmation of the applicability of the reconstructed dose.

Screens, Grids, and Other Factors with the Potential to Affect Work Dose

X-ray tubes used for diagnostic radiography are typically enclosed in protective lead-shielded tube 

housings. The primary beam is transmitted through a port or window in the side of the housing. 

Although some reduction of dose to the worker is achieved, primarily through elimination of scattered 
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radiation and improved collimation, the main purpose of the tube housing is protection of the operator, 

unexposed X-ray film, and nearby individuals other than the worker. This issue should not be 

considered a factor for dose reconstruction because virtually all X-ray tubes used during the period of 

DOE operations (including the tubes assumed to be in use at DOE sites) were designed with 

protective tube housings.

The amount of exposure required for an acceptable diagnostic radiograph is to a certain degree a 

function of film speed and development. Fine grain emulsions produce a superior radiographic image 

but require additional exposure in comparison to fast films. Additional exposure might be required to 

achieve satisfactory radiographic quality and to avoid underdevelopment of films. Intensifying screens 

can be used in the cassette to intensify the radiographic effect, thereby increasing film speed and 

reducing worker dose. Grids, specifically the Potter-Bucky diaphragm (colloquially known as a Bucky) 

are sometimes used for thick section radiography, but rarely for chest radiography (except for large 

workers). These additional parameters are factored into the technique (i.e., kVp, mA) used and, 

except in rare instances and a virtually complete absence of other data, are not important in dose 

reconstruction.

3.1.6

A degree of confusion might have been engendered at many DOE sites and at various periods by the 

use of a variety of conversion coefficients to calculate exposure to absorbed dose. At various times 

an exposure of 1 R has been equated to a soft tissue dose of 0.83, 0.877, or 0.93 rad. Using these 

values, an exposure to air of 1 R would result in an absorbed dose of less than 1 rad (1 cGy = 10 

mGy). However, regulations applicable to DOE sites have defined 1 R as equal to a dose of 1 rad 

(10 mGy). Using this value would produce an overestimate in the reported dose or dose equivalent 

because dosimeters were typically calibrated against a field measured in R, which was numerically 

equated as absorbed dose in rad (Kathren and Petersen 1989). Further complicating the conversion 

of ESE in terms of exposure to absorbed dose is the contemporary trend to refer to X-ray intensity in 

terms of the quantity kerma, which is measured in the same units as absorbed dose. Typically, the 

numerical value of kerma is slightly lower than the corresponding value of absorbed dose. Therefore, 

to ensure conservatism and compliance with NIOSH requirements (NIOSH 2002), and to avoid risk 

dose underestimation, 1 R of exposure was accepted as equal to1 rad of absorbed dose and to 1 rad 

(10 mGy) of kerma.

Assumptions for Dose Conversion

Conversion of exposure expressed as ESE has been conducted in accordance with published 

conversion coefficients in Tables A2 through A9 of ICRP 34 (ICRP 1982). These tables provide 

average absorbed organ doses for selected medical radiography procedures related to an entrance 

air kerma (without backscatter) of 1 Gy for various beam qualities expressed in terms of HVL of 

aluminum. However, the tables do not include all organs identified in the IREP code. For organs 

included in the IREP but not specifically identified in ICRP 34, application of the dose conversion 

coefficient for the anatomically analogous organ that is identified in ICRP 34 is a reasonable and 

simple first-order approach that generally would be claimant-favorable (or at least neutral). Using this 

approach, the factor for lungs would be applied to all other organs in the thoracic cavity (i.e., thymus, 

esophagus, liver, gall bladder and stomach). Because an appreciable fraction of the skeleton, in 

particular the trabecular bone, which has a large surface-to-volume ratio, and the sternum, which is a 

primary location of red marrow in the adult, is in the trunk, the factor for lung would be applied to bone 

surfaces. The dose conversion factor for the ovary would be used for organs in the abdomen (i.e., 

urinary bladder and colon). For the eye, the analogous organ is the thyroid. 

Based on the preceding discussion, a value of 1 R was equated to 10 mGy of kerma. Conversion is 

simple if the beam quality is known. Unfortunately, measured beam quality data were not identified in 
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the site documentation. However, the kVp and filtration are known and beam quality can be 

estimated from these data. Because exposure (mAs) as absorbed organ dose increases as a 

function of HVL for a given amount of filtration, the upper limit on the likely beam quality has been 

calculated and rounded upward (for conservatism) to match the closest value in the tables in ICRP 34. 

Determination of dose requires consideration of two correlated factors: the HVL, which represents a 

function of peak tube potential; and added filtration, which is a function of the thickness of a filter 

added for beam hardening. The conservative value of HVL as a function of peak tube potential was 

used based on Table A16 in ICRP 34. For the period of October 1951 to February 1977, the beam 

quality as HVL and the value for added filtration both were expressed as 2.5 mm of aluminum (based 

on assumptions from measurements taken in November 1961). Starting in March 1977 until the 

present the reported added filtration is 3.0 mm of aluminum. From the period of March 1977 to 

February 1988, an HVL of 3.0 mm of aluminum was used for all organ dose estimates; this value was 

changed to 3.5 mm for the period of March 1988 until June 1999, and was changed to 4.0 mm from 

July 1999 until the present. Organ dose was determined by using the closest values in the tables A2 

to A9 in ICRP 34.

3.2 EXAMINATION FREQUENCIES

The frequency of medical examinations varied over the years of FEMP operation. There is no 

evidence that occupational X-rays might have occurred more frequently than on the schedule 

indicated in Table 3-2. This table lists the frequencies of chest X-rays for different age groups over 

ranges of years and identifies the correlated groups of workers. 

Table 3-2. Frequency of occupational chest X-rays at FEMP. 

Period Frequency Comment

1952–1981 Annually All employees

Annually Construction asbestos workers

1981–2002 Annually Employees over 45 years old

Every 2 years (offered) Employees under 45 years old

In a review of claimant files, it was noted that approximately 15% of the claims reported a re-take of 

the chest X-ray. 

It also was noted in reviewing claimant files that lumbar spine X-rays were taken primarily for 

construction worker and laborers. In a telephone communication with Mr. Louis C. Bogar, the former 

Vice President of ES&H for FEMP, on October 28, 2003, he clearly stated that lumbar spine X-rays 

and any X-rays other than chest were not taken as occupational or pre-employment requirements.

Several telephone communications were conducted with Ms. Betty Smith, a former registered nurse 

who worked at FEMP from1953 until 1993, and with Ms. Diane Jacobowski, a former X-ray 

technologist who worked at FEMP from 1986 to 2002, confirmed that no photofluorographic X-rays 

were performed at any time at FEMP.

3.3 EQUIPMENT AND TECHNIQUES

Although medical practices at FEMP are assumed to have followed the standards of radiology 

practice during the 1940s and later for minimizing worker dose, there has been the potential for 

significant dose from occupational medical X-ray examinations. The magnitude of this type of dose 

depends on the type of equipment, the technique factors, and the number of radiographic 
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examinations. Many FEMP medical records include notations on both the date and the purpose of Xray examinations.

X-ray organ dose estimates for occupational X-rays administered at FEMP are calculated for Type I 

equipment (used from 1951 through 1983), Type II equipment (used from 1983 to March 1988), and 

Type III equipment (used from March 1983 to 2002). Table 3-3 summarizes the X-ray equipment 

used at FEMP.

Table 3-3. Description of FEMP X-ray equipment. 

Technique Period Equipment

Type I 1951–1977 Keleket X-ray unit, 2.5-mm Al equivalent filtration, no grid, manual/hand processing, 

manual collimator.

Type II 1977-19882 Bennett X-ray Corp. Model 300 Vet-7, manual/hand processing.

Type III 1988–2002 General Electric Company Model 46-2611-85G1, manual/hand processing.

Because no technique factors were clearly identified at FEMP for Type I equipment from the 

beginning of operations to February 24, 1977, organ doses based on assumed technique factors were 

developed by comparing X-ray techniques from the period (i.e., 1951 to 1977) with due consideration 

to claimant favorability. Accordingly, an operating kVp of 90 was assumed, which is somewhat higher 

(and therefore claimant-favorable) than the kVp values typically used at the time. External filtration 

was reported to be 2.5 mm of aluminum. The SSD was assumed to be 152 cm, based on a SID of 

183 cm less a chest thickness of 26 cm and an addition of 5 cm to account for cassette thickness.

A survey was conducted in 1961 of diagnostic X-ray units and the associated radiation levels at 

various kVps and mAs. The purpose of this survey was to determine what radiation exposures would 

be recorded on the film badge during medical procedures at various kVps if the badge was 

inadvertently left on the individual or accidentally exposed to X-rays during medical procedures. 

Measurements were taken with a Victoreen condenser R-meter and compared to average output of 

diagnostic equipment from National Bureau of Standards (NBS) Handbook 76 (NBS 1961). If no 

measurements were provided, a dose was calculated using an average decrease of 22% estimated 

from other actual measurements. Table 3-4 lists the results of this survey as an aid for dose 

reconstruction of early (pre-1977) exposures. 

Table 3-4. 1961 survey of X-ray units.*

kVp mAs

Distance 

(inches)

Average

exposure (R)

Measured 

exposure

% Decrease 

from avg.

Calculated 

dose (22%)

30 50 34 0.10 0.085 15 ---

50 150 36 0.30 0.225 25 ---

50 200 24 0.80 0.60 25 ---

50 300 18 1.60 1.40 12 ---

50 350 18 2.80 2.20 21 ---

70 20 36 0.10 0.072 28 ---

70 60 36 0.30 0.225 25 ---

70 180 36 0.90 0.720 20 ---

70 300 36 1.50 1.200 20 ---

70 250 24 2.75 2.000 27 ---

90 50 72 0.10 --- 0.078

90 150 72 0.30 --- 0.234

90 100 36 0.90 --- 0.702

90 75 24 1.43 --- 1.112

90 150 24 2.85 --- 2.220

*Brown 2002, section labeled (A) --1961 Keleket X-ray, Unit Survey of X-ray Unit.

 

2. There is no data on the actual dates that the Bennett X-ray unit was in operation; therefore, the measured data from 

February 1977 was applied from the period of 1977 to 1988.
Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 13 of 26

A conservative exposure time for the period before February 24, 1977, can be estimated in the order 

of 20 mAs. There is no indication that FEMP used voltages higher than 90 kVp for PA chest X-rays 

during this period. ESE for the period before 1977 was calculated based on average exposure level of 

100 mR/hr for 50 mAs at 183 cm and adjusted to 20mAs at 152cm. The calculations conservatively 

estimate the ESE to be 58.0 mR.

A series of measurements were performed on February 24, 1977, to determine the ESE that would be 

received during a medical X-ray of various body parts based on the X-ray techniques used at FEMP. 

Table 3-5 lists the conditions for these calculations. 

Table 3-5. X-ray conditions and power used.*

Location

Body part

thickness (cm)

Filter

(mm Al)

Distance 

(inches) kVp mAs

Chest (PA) 23 3.0 72 74 6.7

Skull (lateral) 15 3.0 40 78 60

Cervical spine (AP) 13 3.0 40 70 40

Thoracic spine (AP) 23 3.0 40 81 100

Lumbar spine (AP) 23 3.0 40 70 150

Foot (DP) 8 3.0 40 44 100

Abdomen (AP) 23 3.0 40 76 60

* Brown 2002, section labeled (B) Entrance Skin Exposure From Medical X-rays.

The measurements were performed to assure management that exposures for all X-rays of interest 

were less than the proposed ESE Guides published in the Federal Register (Vol. 42, No 17, January 

26, 1977, p. 4884). Table 3-6 presents the results of these measurements.

Table 3-6. Calculated and measured results of entrance skin 

exposure and comparison with proposed guides.*

Location mR/mAs

Entrance skin 

exposure (mR)

Proposed 

exposure guide

Chest (PA) 1.7 11.4 30

Skull (lateral) 4.65 279 300

Cervical spine (AP) 3.68 147 250

Thoracic spine (AP) 5.08 508 900

Lumbar spine (AP) 3.67 551 1,000

Foot (DP) 1.08 108 270

Abdomen (AP) 4.38 263 750

*Brown 2002, section labeled (B) Entrance Skin Exposure From Medical X-rays. 

Using the reported information from the series of measurements performed in February 1977, a value 

of 10 mAs of exposure time for an extra large man is used in the conservative estimate of the ESE. 

Therefore, the estimate of the ESE from the period of March 1977 to February 1988 is 1.7 mR/mAs 

times 10 mAs to determine an ESE of 17.0 mR.

In July 1987, Standard Operating Procedure (SOP) ESH-P-12-004, “Preparation and Activation of a 

Diagnostic X-ray,” was issued (Brown 2002). A summary of the techniques cited in this report is 

provided in Table 3-7. An implemented policy stated that chest X-rays were mandatory for 

preemployment physicals and were available annually thereafter. Other X-ray(s) were performed as 

required by a physician. Female candidates were required to read and sign a pregnancy form that 

was included in her personnel/employment file. An individual wishing to exercise the option to not 

accept the chest X-ray offered as part of the annual physical was required to read and sign an X-ray

refusal form.
Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 14 of 26

Table 3-7. X-ray techniques (issue date 7/23/87).*

Location Milliamp (mA) Time (sec) kVp mAs Subject

Chest PA-100 1/30 80-84 3 Avg. woman

PA-100 1/15 80-84 6 Lg. woman

LAT-100 1/15 90-100 6 Avg. woman

PA-100 1/20 80 5 Avg. man

PA-100 1/15 90 6 Lg. man

PA-100 1/10 85-90 10 X-lg. man

LAT-100 1/10 100-115 10 Avg. man

*Brown 2002, section labeled (F) “Preparation and Activation of a Diagnostic X-ray.” 

In March of 1988 FEMP purchased a new General Electric X-ray system. The calculated entrance 

skin exposure for this unit was approximately 12.2 mR. The ESE was calculated with the technique 

factor of 100kVp, 5.0 mAs, (160 mA and 0.033 second); this represents the technique typically set by 

the technologist. 

Beginning January 30, 1991, the State of Ohio Department of Health and Human Services (DHHS) 

conducted diagnostic X-ray assurance surveys that included an evaluation of the chest projection 

technique/exposure. A LuCal chest phantom was used for all of the exposure measurements. The 

measured results of the entrance skin exposure for subsequent years are listed in Table 3-8.

Table 3-8. Measured entrance skin exposures. *

Year kVp mAs SID, in. Entrance skin exposure

1991 100 5.0 72 12.2 mR (AEC)**

1993 100 5.0 72 15.3 mR (AEC)

1995 110 8 72 28.0 mR (Manual)

1997 126 8 72 17.5 mR (AEC)

1997 110 8 72 32.2 mR (Manual)

2000 126 6.4 72 30.2 mR (Manual)

*Brown 2002, section labeled Exposure Survey Results – Bi-ennial FDA 

inspections

**Calculated by DHHS on January 22, 1991

The use of different film screen systems and automatic exposure control (AEC) versus manual 

operation can cause a significant difference in entrance skin exposure. Measurements performed 

during the early years, as noted in Table 3-8, used AEC. Occupational medical X-rays on workers 

might have used manual settings. For the values in this TBD section, the higher value reported was 

applied to estimate organ doses.

A 1995 survey by the DHHS noted a significant increase in the entrance skin exposure over the 1993 

survey (i.e., from 15.3 mR to 28.0 mR). The FEMP response was that since the 1993 inspection (and 

following a risk/benefit analysis) FEMP had switched (for approximately 1 year) to the Kodak InSight 

Thoracic Imaging System. This system was designed to improve overall clinical performance related 

to chest examinations. It enabled FEMP to obtain significantly more usable information during a 

single session in comparison to the former “conventional” imaging system. The new system required 

changes in equipment settings (i.e., the technique) to accommodate and allow for the best diagnostic 

utilization of the technically superior film. The “increased” measured ESE of 28 mR using the new 

technology was still below the recommended Federal ESE guideline of 30 mR for routine chest 

radiography.

A 1997 DHHS survey found that the measured ESE was 32.2 mR. The technique used was a manual 

mode at 110 kVp and 8 mAs. The survey noted that the film optical density (OD) was outside the 
Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 15 of 26

defined range. DHHS recommended that FEMP contact the service representative for the X-ray 

system and the Kodak film representative to discuss methods to lower patient ESE, and change 

exposure techniques from a manual to a phototimed process. FEMP made the recommended 

changes to improve the OD, and in a return inspection DHHS measured the ESE to be 19.2 mR. The 

technique used was 4 mAs at 126 kVp. For the assessment of organ doses during this period, the 

higher ESE of 32.2mR was used.

In a July 1, 1999 survey, DHHS determined that the (apparently) continued manual techniques at 

FEMP yielded an ESE for PA chest X-ray of 30.2 mR at 6.4 mAs and 126 kVp. The same test using 

the AEC at 126 kVp found the ESE to be 16.4 mR for a film density of 1.24. In the AEC mode, the 

optical density was well outside the recommended range. DHHS recommended continuing the use of 

the manual mode.

In an April 13, 2000, DHHS survey, the ESE for PA chest X-ray was 30.2 mR. The manual technique, 

126 kVp and 6.4 mAs, was used for this survey. DHHS did not recommend any changes.

Table 3-10 at the end of this TBD section summarizes the X-ray beam parameters for 14- x 17-in PA 

chest radiography examinations. 

3.4 ORGAN DOSE CALCULATIONS

Tables 3-11 and 3-12 at the end of this TBD section list specific organ doses to be attributed for PA 

chest X-rays calculated on the basis of the dose conversion factors provided in ICRP 34.

Organ doses from lateral chest radiography have been estimated at 2.5 times greater than those from 

corresponding PA doses, based primarily on the greater mAs exposure per radiograph and the 

somewhat smaller SSD. For organs not listed in the ICRP reference (ICRP 1982) but specified in the 

IREP code, doses were determined by analogy with anatomical location, as listed in Table 3-9. 

Table 3-9. Analogues for IREP organs not in ICRP 34. 

Anatomical 

location

ICRP 34

reference organ IREP organ analogues

Thorax Lung Thymus; esophagus; stomach; bone surface; 

liver/gall bladder; remaining organs

Abdomen Ovaries Urinary system/bladder; colon/rectum

Head and neck Thyroid Eye/brain

Based on this approach, IREP code organs in the thoracic cavity but not mentioned in ICRP 34 were 

assigned the same dose as the lungs; doses to the organs in the head and neck should be assigned 

the same dose as the thyroid. The head and neck organ dose estimates (i.e., eye/brain) should be 

slightly greater than doses actually incurred (and therefore claimant-favorable) because of geometry 

considerations and, at least in the case of the brain, because of attenuation by the bony cranium. 

Skin doses were determined by multiplying the ESE by the backscattering factor (1.4 HLVs for 4.0 

mm of aluminum) from NCRP data (NCRP 1985, Table B-8).

Tables 3-13 through 3-19 at the end of this TBD section summarize organ dose data for FEMP 

occupational medical exposures.
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3.5 UNCERTAINTY

Error, defined as deviation from the correct, true, or conventionally accepted value of a quantity, and 

uncertainty, defined in terms of the potential range of a stated, measured, assumed, or otherwise 

determined value of a quantity, provide an indication of the confidence of the dose estimates. Error 

implies knowledge of the correct or actual; therefore, the more appropriate term is uncertainty, which 

is expressed in terms of a confidence level, e.g., 99% (i.e., the correct or true value, although not 

actually known, has a 99% probability of falling within the range cited), and includes both precision or 

reproducibility of the measurement and accuracy, or how close the measurement or estimate of dose 

approaches the actual or correct value.

Although in theory a large number of factors can introduce uncertainties or affect the X-ray machine 

output intensity and dose to the patient, in practice only four factors can reasonably have a significant 

impact on dose uncertainty: variation in applied kilovoltage, variation in beam current, variation in 

exposure time, and distance from the patient to the source of the X-rays (SSD). The influence of 

other factors such as the use of screens, grids, reciprocity failure, film speed, and development, while 

potentially variable, would not affect the beam output intensity.

For a given set of machine settings and parameters, X-ray output theoretically should be constant and 

unvarying. However, this is not true in practice, although output is essentially constant unless focal 

spot loading occurs, as when the power rating of the machine is exceeded. It is unlikely that power 

ratings were ever exceeded; this would have been difficult to achieve in practice and would have 

resulted in damage to the X-ray tube. However, even with the use of “constant voltage” transformers

to control line voltages, slight variations could have occurred in line voltage input or other internal 

voltages, which in turn could have altered the kVp of the output beam. In general, for a given kVp 

setting, variation in kVp falls within ±5% of the machine setting. Because beam intensity is 

approximately proportional to the 1.7 power of the kilovoltage, this translates to an uncertainty of 

approximately ±8.7% for output beam intensity in the 100- to 120-kVp range used for diagnostic 

radiographs at FEMP. For conservatism, this is rounded up to ±9%.

Similar, slight variations in tube current are normal; as a tube ages, or heats from use, tube current 

can change and typically will drop. Therefore, with all other factors remaining constant, beam 

intensity will be reduced in direct proportion to the change in tube current. Typically, the reduction in 

beam output from current variation is not more than a few percent under normal operating conditions. 

Large decreases in beam output will be readily detected and result in maintenance on the machine to 

restore the output or, as a temporary measure, an increase in the current or kVp to provide the 

necessary intensity for proper radiography. There is no evidence to suggest that these measures 

were ever necessary or applied at FEMP. For a given kVp setting, the output of the beam is a 

function of tube current, which in turn is measured by a milliammeter on the machine. The 

measurement is subject to uncertainties, and there might be minor changes in output as the tube 

heats from normal use. Because these variations are typically small, uncertainty in beam output 

attributable to current variation has been estimated at ±5%.

Another parameter that can affect the dose, perhaps significantly, from a diagnostic radiograph relates 

to the time of exposure. This can be understood by noting that a full-wave rectified machine produces 

120 pulses per second of X-rays. For an exposure time of 1/20 of a second, only six pulses would 

result. A small error in the timer that resulted in a change of only ±1 pulse would affect the output by 

±17%; for an exposure time of 1/30 of a second, the change in output corresponding to a deviation of 

±1 pulse is ±25%. Early mechanical timers were notoriously inaccurate, and timer accuracy improved 

significantly with the introduction of electronic timers. However, for conservatism, uncertainty in beam 

output attributable to timers will be assumed to have an upper limit of +25%.
Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 17 of 26

The final factor that is likely to affect worker dose relates to distance from the source of the X-rays, 

which is a determinant of the entrance skin exposure. For a given individual, the SSD will be 

determined largely by the thickness of the patient, and the accuracy of the positioning. For a typical 

patient, this variation in SSD is estimated at no more than a few centimeters, with an upper limit of 

perhaps 7.5 cm. Using inverse square calculations, this indicates an uncertainty of ±10% from this 

source.

There are two approaches to determine the combined uncertainty from the four potential sources of 

uncertainty discussed above. The first, and most conservative in that it gives the greatest range, 

would be to assume that the uncertainties are additive, which would give an uncertainty range of up to 

9 + 5 + 25 + 10 = 49. However, a more reasonable approach would be to assume that the 

uncertainties are in fact random, and to compute the statistical root mean square (RMS) value. The 

RMS value is simply the square root of the sum of the squares, and computes as ±28.7%. Therefore, 

for an individual ESE or derived organ dose, an uncertainty of ±30% at the 1 sigma level can be 

assumed. For further conservatism it might be appropriate to assume that errors are all positive, and 

only +30% should be used.

One annual X-ray procedure for each full or partial year of employment is assumed. However, if the 

dose reconstructor determines that more frequent procedures occurred or might have occurred, the 

annual organ doses can be increased accordingly.
Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 18 of 26

Table 3-10. Summary of beam parameters for 14" × 17 " PA chest radiography.

Date measured 4/2000 7/1999 5/1997 3/1995 4/1993 1/1991 2/1977 11/1961

Procedure Chest PA 

14"×17"

Chest PA 

14"×17"

Chest PA 14"×17" Chest PA 14"×17" Chest PA 14"×17" Chest PA 

14"×17"

Chest PA 

14"×17"

Chest PA

14"×17"

Machine type GE Model 46 GE Model 46 GE Model 46 GE Model 46 GE Model 46 GE Model 46 Bennett 300 Keleket

Machine settings kVp: 126 126 110 110 100 100 90 90

mA 200 200 100 100 100 100 100 150

Exposure time 1/30 sec 1/30 sec 1/30 sec 1/20 sec 1/20 sec 1/20 sec 1/10 sec 1/15 sec

mAs 6,4 6.4 8 ( m ) 8 5 5 10 20

Added filter 3.0 mm 3.0 mm 3.0 mm 3.0 mm 3.0 mm 3.0 mm 3.0 mm 2.5 mm

HVL (filtration used for 

calculations)

4.0 mm 4.0 mm 3.5 mm 3.5 mm 3.5 mm 3.5 mm 3.0 mm 2.5 mm

Skin to image distance 183 cm 183 cm 183 cm 183 cm 183 cm 183 cm 183 cm 183 cm

Entrance skin exposure 30.2 mR 30.2 mR 32.2 mR 28 mR 15.3 mR 12.2 mR 17.0 mR 58.0 mR

(assumed)

mR/mAs 4.7 4.7 4.0 3.5 3.1 2.4 1.7 1.6

Date range 7/99-present 4/95-6/99 5/93-3/95 2/91-4/93 3/88-1/91 3/77-2/88* 10/51-2/77

Reference source DHHS FERMCO** DHHS DHHS DHHS DHHS NLO***, FMPC FMPC

* There is no data on the actual dates that the Bennett X-ray unit was in operation; therefore, the measured data from 02/77 was applied from the period of 03/77 to 02/88.

** Fernald Environmental Restoration Management Corp, or FERMCO.

*** National Lead of Ohio, Inc.
Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 19 of 26

Table 3-11. Average absorbed chest X-ray dose (mGy) for selected organs for 1 Gy 

entrance kerma (air kerma without backscatter) for a beam quality of 2.5 mm of aluminum 

(HVL).

a

Organ View

Source-image 

distance (cm)

Image receptor 

size (cm)

Dose conversion factor 

(mGy per Gy air kerma; 

beam quality 2.5 mm 

aluminum HVL)

Thyroid PA 183 35.6 × 43.2 32

Lat. 183 35.6 × 43.2 115

Ovaries PA 183 35.6 × 43.2 1

Lat. 183 35.6 × 43.2 0.6

Testes PA 183 35.6 × 43.2 0.01

Lat. 183 35.6 × 43.2 0.1

Lungs (male) PA 183 35.6 × 43.2 419

Lat. 183 35.6 × 43.2 193

Lungs (female) PA 183 35.6 × 43.2 451

Lat. 183 35.6 × 43.2 220

Breast PA 183 35.6 × 43.2 49

Lat. 183 35.6 × 43.2 255

Uterus PA 183 35.6 × 43.2 1.3

Lat. 183 35.6 × 43.2 0.6

Bone marrow (male) PA 183 35.6 × 43.2 92

Lat. 183 35.6 × 43.2 37

Bone marrow (female) PA 183 35.6 × 43.2 86

Lat. 183 35.6 × 43.2 29

Total body (male) PA 183 35.6 × 43.2 131

Lat.b 183 35.6 × 43.2 64

Total body (female) PA 183 35.6 × 43.2 118

Lat. 183 35.6 × 43.2 60

a. Dose conversion factors from Tables A.2 through A.9 from ICRP (1982).

Table 3-12. Average absorbed chest X-ray dose (mGy) for selected organs for 1 Gy 

entrance kerma (air kerma without backscatter) for a beam quality of 3.0 mm of 

aluminum (HVL).

a

Organ View

Source-image 

distance (cm)

Image receptor 

size (cm)

Dose conversion factor 

(mGy per Gy air kerma; 

beam quality 3.0 mm 

aluminum HVL)

Thyroid PA 183 35.6 × 43.2 46

Lat. 183 35.6 × 43.2 133

Ovaries PA 183 35.6 × 43.2 1.8

Lat. 183 35.6 × 43.2 0.9

Testes PA 183 35.6 × 43.2 0.01

Lat. 183 35.6 × 43.2 0.1

Lungs (male) PA 183 35.6 × 43.2 496

Lat. 183 35.6 × 43.2 236

Lungs (female) PA 183 35.6 × 43.2 535

Lat. 183 35.6 × 43.2 267

Breast PA 183 35.6 × 43.2 69

Lat. 183 35.6 × 43.2 287

Uterus PA 183 35.6 × 43.2 2.3

Lat. 183 35.6 × 43.2 0.9

Bone marrow (male) PA 183 35.6 × 43.2 117

Lat. 183 35.6 × 43.2 48

Bone marrow (female) PA 183 35.6 × 43.2 112

Lat. 183 35.6 × 43.2 38

Total body (male) PA 183 35.6 × 43.2 153

Lat. 183 35.6 × 43.2 83

Total body (female) PA 183 35.6 × 43.2 145

Lat. 183 35.6 × 43.2 77

a. Dose conversion factors from Tables A.2 through A.9 from ICRP (1982).
Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 20 of 26

Table 3-13. Organ dose estimates for FEMP chest radiographs 

from 10/1951 to 1/1977. 

Organ View Organ dose (mGy) Organ dose (rem)

Thyroid PA 1.86E-02 1.86E-03

Lat. 6.68E-02 6.68E-03

Ovaries PA 5.80E-04 5.80E-05

Lat. 3.48E-04 3.48E-05

Testes PA 5.80E-06 5.80E-07

Lat. 2.90E-05 2.90E-06

Lungs (male) PA 2.44E-01 2.44E-02

Lat. 1.12E-01 1.12E-02

Lungs (female) PA 2.60E-01 2.60E-02

Lat. 1.28E-01 1.28E-02

Breast PA 2.86E-02 2.86E-03

Lat. 1.31E-01 1.31E-02

Uterus PA 7.56E-04 7.56E-05

Lat. 3.48E-04 3.48E-05

Bone marrow (male) PA 5.34E-02 5.34E-03

Lat. 2.14E-02 2.14E-03

Bone marrow (female) PA 4.98E-02 4.98E-03

Lat. 1.68E-02 1.68E-03

Total body (male) PA 7.56E-02 7.56E-03

Lat. 3.72E-02 3.72E-03

Total body (female) PA 6.84E-02 6.84E-03

Lat. 3.48E-02 3.48E-03

Skin 8.14E-01 8.14E-02

Table 3-14. Organ dose estimates for FEMP chest radiographs 

from 2/1977 to 2/1988. 

Organ View Organ dose (mGy) Organ dose (rem)

Thyroid PA 7.80E-03 7.80E-04

Lat. 2.25E-02 2.25E-03

Ovaries PA 3.04E-04 3.04E-05

Lat. 1.52E-04 1.52E-05

Testes PA 1.69E-06 1.69E-07

Lat. 1.69E-05 1.69E-06

Lungs (male) PA 8.40E-02 8.40E-03

Lat. 4.00E-02 4.00E-03

Lungs (female) PA 9.05E-02 9.05E-03

Lat. 4.51E-02 4.51E-03

Breast PA 1.17E-02 1.17E-03

Lat. 4.86E-02 4.86E-03

Uterus PA 3.90E-04 3.90E-05

Lat. 1.52E-04 1.52E-05

Bone marrow (male) PA 1.98E-02 1.98E-03

Lat. 8.13E-03 8.13E-04

Bone marrow (female) PA 1.89E-02 1.89E-03

Lat. 6.44E-03 6.44E-04

Total body (male) PA 2.59E-02 2.59E-03

Lat. 1.40E-02 1.40E-03

Total body (female) PA 2.37E-02 2.37E-03

Lat. 1.30E-02 1.30E-03

Skin 2.37E-01 2.37E-02
Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 21 of 26

Table 3-15. Organ dose estimates for FEMP chest radiographs from 

3/1988 to 1/1991. 

Organ View Organ dose (mGy) Organ dose (rem)

Thyroid PA 7.57E-03 7.57E-04

Lat. 1.85E-02 1.85E-03

Ovaries PA 3.92E-04 3.92E-05

Lat. 1.96E-04 1.96E-05

Testes PA 1.22E-05 1.22E-06

Lat. 1.22E-04 1.22E-05

Lungs (male) PA 6.87E-02 6.90E-03

Lat. 3.37E-02 3.37E-03

Lungs (female) PA 7.44E-02 7.44E-03

Lat. 3.78E-02 3.78E-03

Breast PA 1.11E-02 1.11E-03

Lat. 3.85E-02 3.85E-03

Uterus PA 3.65E-04 3.65E-05

Lat. 1.72E-04 1.72E-05

Bone marrow (male) PA 1.79E-02 1.79E-03

Lat. 7.43E-03 7.43E-04

Bone marrow (female) PA 1.71E-02 1.71E-03

Lat. 5.85E-03 5.85E-04

Total body (male) PA 2.12E-02 2.12E-03

Lat. 1.14E-02 1.14E-03

Total body (female) PA 1.96E-02 1.96E-03

Lat. 1.09E-02 1.09E-03

Skin 1.71E-01 1.71E-02

Table 3-16. Organ dose estimates for FMPC chest radiographs from 

2/1991 to 4/1993. 

Organ View Organ dose (mGy) Organ dose (rem)

Thyroid PA 9.50E-03 9.50E-04

Lat. 2.31E-02 2.31E-03

Ovaries PA 4.90E-04 4.90E-05

Lat. 2.44E-04 2.44E-05

Testes PA 1.53E-06 1.53E-07

Lat. 1.53E-05 1.53E-06

Lungs (male) PA 8.65E-02 8.65E-03

Lat. 4.24E-02 4.24E-03

Lungs (female) PA 9.33E-02 9.33E-03

Lat. 4.73E-02 4.73E-03

Breast PA 1.40E-02 1.40E-03

Lat. 4.83E-02 4.83E-03

Uterus PA 4.58E-04 4.58E-05

Lat. 2.14E-04 2.14E-05

Bone marrow (male) PA 2.24E-02 2.24E-03

Lat. 9.33E-03 9.33E-04

Bone marrow (female) PA 2.15E-02 2.15E-03

Lat. 7.33E-03 7.33E-04

Total body (male) PA 2.71E-02 2.71E-03

Lat. 1.44E-02 1.44E-03

Total body (female) PA 2.46E-02 2.46E-03

Lat. 1.36E-02 1.36E-03

Skin 2.14E-01 2.14E-02
Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 22 of 26

Table 3-17. Organ dose estimates for FMPC chest radiographs from 

5/1993 to 3/1995. 

Organ View Organ dose (mGy) Organ dose (rem)

Thyroid PA 1.74E-02 1.74E-03

Lat. 4.24E-02 4.24E-03

Ovaries PA 8.95E-04 8.95E-05

Lat. 4.47E-04 4.47E-05

Testes PA 2.80E-06 2.80E-07

Lat. 2.80E-05 2.80E-06

Lungs (male) PA 1.58E-01 1.58E-02

Lat. 7.75E-02 7.75E-03

Lungs (female) PA 1.71E-01 1.71E-02

Lat. 6.44E-02 6.44E-03

Breast PA 2.56E-02 2.56E-03

Lat. 8.84E-02 8.84E-03

Uterus PA 8.39E-04 8.39E-05

Lat. 3.92E-04 3.92E-05

Bone marrow (male) PA 4.10E-02 4.10E-03

Lat. 1.71E-03 1.71E-04

Bone marrow (female) PA 3.94E-02 3.94E-03

Lat. 1.35E-02 1.35E-03

Total body (male) PA 4.88E-02 4.88E-03

Lat. 2.62E-02 2.62E-03

Total body (female) PA 4.51E-02 4.51E-03

Skin 3.92E-01 3.92E-02

Table 3-18. Organ dose estimates for FMPC chest radiographs from 

4/1995 to 6/1999. 

Organ View Organ dose (mGy) Organ dose (rem)

Thyroid PA 2.00E-02 2.00E-03

Lat. 4.82E-02 4.82E-03

Ovaries PA 1.03E-03 1.03E-04

Lat. 5.14E-04 5.14E-05

Testes PA 3.22E-06 3.22E-07

Lat. 3.22E-05 3.22E-06

Lungs (male) PA 1.82E-01 1.82E-02

Lat. 8.90E-02 8.90E-03

Lungs (female) PA 1.96E-01 1.96E-02

Lat. 9.95E-02 9.95E-03

Breast PA 2.94E-02 2.94E-03

Lat. 1.02E-01 1.02E-02

Uterus PA 9.63E-04 9.63E-05

Lat. 4.51E-04 4.51E-05

Bone marrow (male) PA 4.71E-02 4.71E-03

Lat. 1.97E-02 1.97E-03

Bone marrow (female) PA 4.54E-02 4.54E-03

Lat. 1.54E-02 1.54E-03

Total body (male) PA 5.60E-02 5.60E-03

Lat. 3.02E-02 3.02E-03

Total body (female) PA 5.18E-02 5.18E-03

Lat. 2.87E-02 2.87E-03

Skin 4.51E-01 4.51E-02
Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 23 of 26

Table 3-19. Organ dose estimates for FMPC chest radiographs from 

7/1999 to present. 

Organ View Organ dose (mGy) Organ dose (rem)

Thyroid PA 2.48E-02 2.48E-03

Lat. 5.23E-02 5.23E-03

Ovaries PA 1.65E-03 1.65E-04

Lat. 7.95E-04 7.95E-05

Testes PA 3.20E-06 3.20E-07

Lat. 3.20E-05 3.20E-06

Lungs (male) PA 2.02E-01 2.02E-02

Lat. 9.53E-02 9.53E-03

Lungs (female) PA 2.15E-01 2.15E-02

Lat. 1.12E-01 1.12E-02

Breast PA 3.71E-02 3.71E-03

Lat. 1.10E-01 1.10E-02

Uterus PA 1.66E-03 1.66E-04

Lat. 6.69E-04 6.69E-05

Bone marrow (male) PA 5.68E-02 5.68E-03

Lat. 2.43E-02 2.43E-03

Bone marrow (female) PA 5.50E-02 5.50E-03

Lat. 1.89E-02 1.89E-03

Total body (male) PA 6.10E-02 6.10E-03

Lat. 3.39E-02 3.39E-03

Total body (female) PA 5.68E-03 5.68E-03

Lat. 3.16E-02 3.16E-03

Skin 4.23E-01 4.23E-02
Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 24 of 26

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Department of Health, Education and Welfare, Rockville, Maryland, p. 159.

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Handloser, J. S., 1951, “Radiation Doses from Diagnostic X-ray Studies,” Radiology 57:252-254.

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

Diagnostic Radiology, Annals of the ICRP, ICRP Publication 34, 9(2/3):1-82.

ICRU (Fifth International Congress on Radiology), 1937, “Recommendations of the International 

Committee for Radiological Units,” Radiology 29:634.

Kathren, R. L., 1965, “Spectral and Output Measurements of a Wide Beam K-Fluorescence Radiator," 

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Effective Date: 02/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0017-3 Page 26 of 26

GLOSSARY

dosimeter

A device used to measure the quantity of radiation received. A holder with radiation-absorbing 

elements (filters) and an insert with radiation-sensitive elements packaged to provide a record 

of absorbed dose or dose equivalent received by an individual. 

dosimetry

The science of assessing absorbed dose, dose equivalent, effective dose equivalent, etc., from 

external and/or internal sources of radiation. 

exposure

As used in the technical sense, exposure refers to a measure expressed in roentgens (R) of 

the ionization produced by photon radiation (i.e., X-rays) in air. 

Gray (Gy)

The special name for the SI unit of absorbed dose. (1 Gy = 1 Jkg-1).

optical density 

The quantitative measurement of photographic blackening; the optical density is defined as D 

= Log10 (Io/I).

photon - X ray

Electromagnetic radiation of energies between 10 keV and 100 keV whose source can be an 

X-ray machine or radionuclide.

rad

The unit of absorbed dose. 

radiation

Alpha, beta, neutron, and photon radiation. 

rem

The rem is a unit of dose equivalent, which is equal to the product of the number of rad 

absorbed and the "quality factor."

Roentgen (R or r)

A unit of exposure to gamma or X-ray radiation. It is defined precisely as the quantity of 

gamma or X-ray radiation that will produce a total charge of 2.58 x 10-4 coulomb in 1 kg of dry 

air STP. An exposure of 1 R is approximately equivalent to an absorbed dose of 1 rad in soft 

tissue for higher (~>100 keV) energy photons.

shielding

Any material or obstruction that absorbs (or attenuates) radiation and thus tends to protect 

personnel or materials from radiation.

X-ray

Ionizing electromagnetic radiation of external nuclear origin or a radiograph.