ORAU TEAM

Dose Reconstruction

Project for NIOSH

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

Page 1 of 29

Document Title:

Oak Ridge National Laboratory – 

Occupational Medical Dose

Document Number: ORAUT-TKBS-0012-3 

Revision: 02

Effective Date: 10/01/2007

Type of Document TBD

Supersedes: Revision 01

Subject Expert(s): Robert E. Burns, Jr.

Site Expert(s): Kenneth Fleming

Approval: Signature on File Approval Date: 09/27/2007

Robert E. Burns, Jr., Document Owner

Concurrence: Signature on File Concurrence Date: 09/12/2007

John M. Byrne, Task 3 Manager

Concurrence: Signature on File Concurrence Date: 09/12/2007

Edward F. Maher, Task 5 Manager

Concurrence: Signature on File Concurrence Date: 09/27/2007

Kate Kimpan, Project Director

Approval: Brant A. Ulsh Signature on File for Approval Date: 10/01/2007

James W. Neton, Associate Director for Science

 New Total Rewrite Revision Page Change

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

REVISION AND DISCARD / DESTROY ALL COPIES OF THE PRIOR REV ISION.
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 2 of 29

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION 

NUMBER DESCRIPTION

04/20/2004 00 New technical basis document addressing occupational medical 

dose for the Oak Ridge National Laboratory. First approved issue. 

Initiated by Robert E. Burns, Jr.

10/29/2004 01 Revised to remove 25% timing error correction from ESE and organ 

dose values from PA chest exams between 1964 and 1990. 

Approved issue of Revision 01. Initiated by Robert E. Burns, Jr.

07/21/2006 01 PC-1 Approved page change revision initiated to incorporate recent 

direction from NIOSH to include details for the definition of a DOE 

facility on page 5 in Section 3.1. Adds Purpose and Scope sections 

on page 6. Revised to delete the uterus as a surrogate organ to the 

ovaries on page 15 in Section 3.5 and on page 24 in Table 3-7 in 

Section 3.4. Makes corrections in Table 3-5 on pages 20 and 21 and 

in Table 3-6 on pages 22 and 23 in Section 3.6. Incorporates NIOSH 

formal review comments. No sections were deleted. This revision 

results in a reduction in assigned dose and no PER is required. 

Initiated by Robert E. Burns, Jr. Approval: 

Robert E. Burns, Jr., TBD Team Leader

Signature on File ________________07/11/2006

John M. Byrne, Task 3 Manager

Signature on File ________________07/11/2006

Edw ard F. Maher, Task 5 Manager

Signature on File ___________________07/11/2006

Kate Kimpan, Project Director

Signature on File ________________07/20/2006

James W. Neton, Associate Director for Science

Signature on File ________________07/21/2006

10/01/2007 02 Approved Revision 02 initiated to include Attribution and Annotation

section. Incorporates formal internal review comments most of which 

were editorial and pertained to more than the added Attributions and 

Annotations section. Table 3-6 had the factor of two removed that 

was applied to the organ dose values for the ovaries, testes, and 

uterus. Incorporates formal NIOSH review comments. Training 

required: As determined by the Task Manager. Initiated by Robert 

E. Burns.
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 3 of 29

TABLE OF CONTENTS

SECTION TITLE

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

PAGE

4

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

3.1.1 Purpose .....................................................................................................................7

3.1.2 Scope ........................................................................................................................7

3.2 Technical Factors Affecting X-Ray Dose ................................................................................7

3.2.1 Peak Applied Voltage and Filtration ............................................................................7

3.2.2 Current and Exposure Time........................................................................................9

3.2.3 Distance...................................................................................................................10

3.2.4 Waveform and Collimation Characteristics................................................................10

3.2.5 Screens, Grids, and Other Factors Potentially Affecting Worker Dose........................11

3.3 X-Ray Doses to ORNL Workers, 1943 to Present................................................................. 12

3.4 Uncertainty Analysis for ORNL Radiography Doses..............................................................17

3.5 Attributions and Annotations ................................................................................................25

References.....................................................................................................................................27

Glossary .........................................................................................................................................29

LIST OF TABLES

TABLE TITLE

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

PAGE

12

3-2 X-ray operating parameters, dates of use, and frequency of examinations 

(provided by ORNL).............................................................................................................13

3-3 Assumptions made to operating parameters provided by ORNL and 

where default parameters were used....................................................................................17

3-4 Values used to calculate organ dose....................................................................................18

3-5 DCFs (Average absorbed dose per unit entrance air kerma) for selected 

X-ray projections, organs, and beam qualities ......................................................................20

3-6 Organ dose estimates for ORNL chest and lumbar spine radiographs to 

be used as IREP inputs .......................................................................................................22

3-7 Surrogate and associated organs.........................................................................................24
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ACRONYMS AND ABBREVIATIONS

Al aluminum

AP anterior-posterior

cGy centigray

cm centimeter

DCF dose conversion factor

DOE U.S. Department of Energy

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

ESE entrance skin exposure

Gy gray

HVL half-value layer

ICRP International Commission on Radiological Protection

ICRU International Commission on Radiological Units and Measurements

IREP Interactive RadioEpidemiological Program

kVp applied kilovoltage, kilovolts-peak

LAT lateral

mA milliampere

mAs milliampere-second

mGy milligray

mm millimeter

mrad millirad

NBS National Bureau of Standards

NCRP National Council on Radiation Protection and Measurements

NIOSH National Institute for Occupational Safety and Health

ORAU Oak Ridge Associated Universities

ORNL Oak Ridge National Laboratory

ORR Oak Ridge Reservation

PA posterior-anterior

PFG photofluorography

POC probability of causation

R roentgen

RMS root mean square

RT radiology technician

SID source-to-image distance

SRDB Ref ID Site Research Database Reference Identification (number)

SSD source-to-skin distance
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 5 of 29

U.S.C. United States Code

X-10 The Oak Ridge National Laboratory site

Y-12 Y-12 National Nuclear Security Complex

§ section or sections
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 6 of 29

3.1 INTRODUCTION

Technical basis documents and site profile documents are not official determinations made by the 

National Institute for Occupational Safety and Health (NIOSH) but are rather general working 

documents that provide historic background information and guidance to assist in the preparation of 

dose reconstructions for 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 staff 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 [DOE] facility” as defined in the Energy Employees 

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

EEOICPA defines a DOE facility as “any building, structure, or premise, including the grounds upon 

which such building, structure, or premise is located ... in which operations are, or have been, 

conducted by, or on behalf of, the Department of Energy (except for buildings, structures, premises, 

grounds, or operations ... pertaining to the Naval Nuclear Propulsion Program)” [42 U.S.C. 

§ 7384l(12)]. Accordingly, except for the exclusion for the Naval Nuclear Propulsion Program noted 

above, any facility that performs or performed DOE operations of any nature whatsoever is a DOE 

facility encompassed by EEOICPA.

For employees of DOE or its contractors with cancer, the DOE facility definition only determines

eligibility for a dose reconstruction, which is a prerequisite to a compensation decision (except for 

members of the Special Exposure Cohort). The compensation decision for cancer claimants is based 

on a section of the statute entitled “Exposure in the Performance of Duty.” That provision [42 U.S.C. 

§ 7384n(b)] says that an individual with cancer “shall be determined to have sustained that cancer in 

the performance of duty for purposes of the compensation program if, and only if, the cancer ... was 

at least as likely as not related to employment at the facility [where the employee worked], as 

determined in accordance with the POC [probability of causation1

As noted above, the statute includes a definition of a DOE facility that excludes “buildings, structures, 

premises, grounds, or operations covered by Executive Order No. 12344, dated February 1, 1982 

(42 U.S.C. 7158 note), pertaining to the Naval Nuclear Propulsion Program” [42 U.S.C. § 7384l(12)]. 

While this definition contains an exclusion with respect to the Naval Nuclear Propulsion Program, the 

section of EEOICPA that deals with the compensation decision for covered employees with cancer 

[i.e., 42 U.S.C. § 7384n(b), entitled “Exposure in the Performance of Duty”] does not contain such an 

exclusion. Therefore, the statute requires NIOSH to include all occupationally derived radiation 

exposures at covered facilities in its dose reconstructions for employees at DOE facilities, including 

radiation exposures related to the Naval Nuclear Propulsion Program. As a result, all internal and 

external dosimetry monitoring results are considered valid for use in dose reconstruction. No efforts 

are made to determine the eligibility of any fraction of total measured exposure for inclusion in dose 

reconstruction. NIOSH, however, does not consider the following exposures to be occupationally 

derived:

] guidelines established under 

subsection (c) ...” [42 U.S.C. § 7384n(b)]. Neither the statute nor the probability of causation

guidelines (nor the dose reconstruction regulation) define “performance of duty” for DOE employees 

with a covered cancer or restrict the “duty” to nuclear weapons work.

• Radiation from naturally occurring radon present in conventional structures

• Radiation from diagnostic X-rays received in the treatment of work-related injuries

 

1 The U.S. Department of Labor is ultimately responsible under the EEOICPA for determining the POC. 
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 7 of 29

3.1.1

Medical X-ray procedures required as preplacement, annual, and termination examinations were and 

are still a contributor to the occupational radiation exposure of workers at the Oak Ridge National 

Laboratory (ORNL) as defined under EEOICPA. Unlike occupational exposures incurred during 

normal work processes, individual medical X-ray exposures were not monitored, necessitating the use 

of the information provided in this document in the reconstruction of dose from these exposures.

Purpose

3.1.2

This document describes the technical aspects of dose reconstruction from medical X-rays 

administered prior to employment (preplacement) and periodically thereafter (typically annual and 

termination) for screening purposes and as a condition of employment at ORNL. Photofluorographic 

(PFG) techniques were used from 1943 through October 3, 1947, to conduct preplacement chest 

examinations for potential ORNL workers. 

Scope

Attributions and annotations, indicated by bracketed callouts and used to identify the source, 

justification, or clarification of the associated information, are presented in Section 3.7.

3.2 TECHNICAL FACTORS AFFECTING X-RAY DOSE

A number of factors affect doses to workers from X-ray procedures. For a standard medical 

radiographic unit with a tungsten target (anode) and focal spot of 1-2 mm, these factors include 

• The peak applied voltage on the X-ray tube (kVp)

• The tube current (mA)

• The time of exposure

• The distance from the X-ray source to the skin or organ of concern

• The waveform of the X-ray generator

• The thickness and type of metal used for filtration (beam hardening)

• The use of collimation or diaphragms to minimize the beam area

• The characteristics of the tube housing

• The type and speed of the film

• Film development procedures

• The use of screens or grids

• The physical size and thickness of the worker

While this list of factors looks formidable, in the absence of direct measurements of the beam itself, 

which might not be available, worker dose can be estimated with a reasonable degree of accuracy 

with knowledge of only the three basic machine parameters (peak applied voltage, tube current, and 

time of exposure) and assumptions about filtration, collimation, and waveform characteristics as 

necessary. The implications of these factors to worker dose are discussed below.

3.2.1

The energy of the X-ray beam, sometimes referred to as beam quality, is determined by the peak 

applied voltage (kVp) and the filtration. X-rays produced in a typical medical X-ray tube are 

bremsstrahlung radiation (a continuous distribution or spectrum of energies ranging from zero up to 

the voltage applied to the tube). This refers to the electronic potential that exists between the anode 

and cathode of the tube. For a typical unfiltered X-ray spectrum, the average photon energy is about 

one-third of the peak energy, or applied voltage. Hence, most X-rays produced by a given voltage are 

Peak Applied Voltage and Filtration
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much lower in energy than the applied voltage of the beam, and are attenuated by the filtration that 

exists in the tube (inherent filtration), any additional filtration used to harden the beam, and the torso 

or other portions of the body through which the primary X-ray beam is focused. These X-rays never 

reach the film and are of little value in radiography, but can contribute significantly to worker dose. To 

reduce the worker dose, filtration in the form of a specified thickness of absorbing material (typically 

aluminum) is placed in the beam after it exits the port. This absorbs a large fraction of the lowerenergy X-rays that are of little or no value in making the radiograph while allowing most of the more 

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

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

correspondingly higher average energy than it had before it was filtered, although the photon fluence 

rate entering the target area is much reduced. Such a beam is said to have been hardened. A 

corollary to this filtration technique is to use a higher applied voltage and to filter the beam relatively 

heavily to prevent most of the low-energy, radiographically useless photons from reaching the worker.

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

half value layer (HVL) in aluminum or other metals such as copper or tin. Unfortunately, this 

parameter is seldom available. Even if it is known, it is of limited value, in part because it does not 

specify the maximum energy of the beam. In addition, it might not reflect the true beam quality, as the 

HVL measurement might be biased depending on how it was performed (i.e., if mathematical 

unfolding techniques were not applied to correct for the effect of the absorbers used in the 

measurement). What is commonly, although not always, available is the kVp of the machine and the 

external filtration that might be added for hardening the beam. All X-ray tubes have so-called inherent 

filtration, which includes glass in the walls, oil that surrounds the tube for cooling, and the window or 

port of the tube head. This window, the thinnest part of the tube housing in medical radiographic

units, is typically equivalent to 0.5 mm Al in attenuation and, hence, provides little beam hardening. 

The inherent filtration asserted by the ORNL medical department staff for the original X-ray machine 

installed in October 1947 (Picker Model R-2) was 0.04 mm Al. Given the disparity between this value 

and what is typical, a beam quality with an HVL of 1.5 mm Al was assumed for the assessment of 

worker exposures from this unit [1]. The total filtration given for this device was found to be 

documented (Lincoln and Gupton 1957, 1958) as 1 mm Al and was used to estimate the entrance 

skin exposure2

Although the benefits of filtration with respect to improved radiographic images were known and 

understood very early on, radiographs were initially made with no added filtration. Recommendations 

made in 1937 by the International Committee for Radiological Units and Measurements (ICRU), albeit 

not specific for thickness, specified aluminum filters for X-rays of 20 to 120 kVp, which incorporated 

the diagnostic X-ray energy range available at that time (ICRU 1937). Typical external filtration in the 

1940s ranged from none to 1 mm Al. This was in line with 1936 recommendations of the U.S. 

Advisory Committee on X-Ray and Radium Protection, which later became the National Council on 

Radiation Protection and Measurements (NCRP), which called for 0.5 mm of Al equivalent for 

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

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

(NBS1949); this thickness was used during World War II in 100-mA units in larger military hospitals. 

Recommended thicknesses were later increased; in 1955, the NCRP recommendation for diagnostic 

(ESE) values for lumbar spine X-ray examinations for the machine used between 1947 

and 1963. The documented skin dose in these same reports was low (21 mrad) for the PA chest Xray examination as compared to skin dose from other chest X-rays given during that timeframe. The 

skin exposure for that timeframe was estimated using operating parameters [2].

 

2 Throughout this document, italics are used to differentiate exposure in the special sense from exposure in the general 

sense. Thus exposure refers to exposure in the special sense. Many publications, including NCRP (1985) and ICRU 

(1998), discuss exposure in both the general and special sense. The definition and application of the quantity exposure and 

its concomitant unit the roentgen have undergone important modifications over the years, as documented in the literature.
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 9 of 29

X-ray units called for 2-mm total Al filtration for new machines (NBS 1955). This increased in 1968 to 

2.5 mm for medical diagnostic units operating above 70 kVp (NCRP 1968). For machines already in 

operation, these recommended filter thicknesses might not have been used for some time after the 

date of the recommendation.

The relationship of beam intensity3

I = Ioe-0.4t (3-1)

to applied voltage and filtration is complex and to some extent 

machine-specific and, therefore, is best determined empirically. In the absence of empirical data for a 

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

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

the 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 Al filtration 

will effect a reduction of about 40% in the ESE (Trout, Kelley, and Cathey 1952; Taylor 1957). Thus, 

the approximate intensity reduction afforded by any thickness of Al filtration can be determined by the 

following exponential equation:

or

ln (I/Io) = -0.4t (3-1)

where t is the thickness of Al 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, which 

is consistent with the guidance in External Dose Reconstruction Implementation Guideline (NIOSH 

2006), can be applied to determine the effect of filtration on beam intensity.

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

using Kramer’s rule, but such calculations are difficult, complex, and time-consuming, even with highspeed computers, and are at best approximations. However, many empirical studies of beam 

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 and Love 1951; Trout, Kelley, and Cathey 1952; Kathren 1965; BRH 

1970). In the absence of specific measurements or empirical data, this function, which is consistent 

with the guidance in NIOSH (2006), can be applied to determine the effect of applied voltage on beam 

intensity.

3.2.2

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

tube current and exposure time. Thus, all factors being equal (e.g., kVp, filtration, film speed, 

development, and screen combination), radiation exposure is directly proportional to the product of 

the tube current and exposure time, 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 voltage, the number of X-ray photons produced, and therefore the 

exposure, will, at least in theory, 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. Thus, in the 

absence of measurements or other data or information to the contrary, it is reasonable and consistent 

with long-standing radiographic practice (Sante 1946) to assume linearity of exposure with tube 

current for a given kVp and filtration.

Current and Exposure Time

 

3 As used herein, 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. 
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 10 of 29

Exposure time refers to the period 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 proportionally increased to 

obtain the desired exposure in terms of mAs. However, earlier medical radiographic units had 

mechanical timers with accuracies that were not as good as those of the electronic timers used on 

later units. It was noted in two surveys conducted at ORNL (Ohnesorge 1979 and Halliburton 1985) 

that the timer for the Westinghouse Riviera instrument was incorrect by between 20 to 25%. Gross 

systematic errors in timer accuracy, however, are typically unlikely in most units 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 perhaps ±20% in the exposure, 

are more subtle. 

Photofluorography of the chest, which resulted in much greater worker doses than a standard 

radiographic procedure, appears to have been used by Oak Ridge Hospital from the inception of 

activities at ORNL (ca. early 1943) until the ORNL Medical Department began using its own 

conventional radiographic X-ray machine in early October 1947. It was stated by the Radiology 

Technician who began working at ORNL in September 1947 that no PFG exams of the chest were 

performed at the ORNL site during physical examinations and none were observed during the site 

visit (Tuck 2003). Although PFG examinations were used as an inexpensive method of conducting 

tuberculosis screenings for large populations, they caused much higher exposures than conventional 

radiographic chest X-ray examinations due to the need for increased exposure time to fluoresce the 

image screen. It appears that stereoscopic PFG views (with 2 exposures) using smaller film (4 × 

10 in.) were used to conduct preplacement examinations for all ORNL workers from 1943 through 

September 1947 [3]. It also appears that if the initial examination indicated the need for a follow-up, 

these were performed via a conventional posterior-anterior (PA) view onto 14- × 17-in. film [4]. (A 

fluoroscopy X-ray unit was acquired at some time early in the history of the ORNL site, but was used 

for a short period of time and only for conducting upper gastrointestinal examinations.)

3.2.3

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)

Distance

4

3.2.4

of 72 in. (source refers to the focal spot of the tube and image to the plane of the film). 

Lumbar spine projections were performed at a SID of 39 in. (see Table 3-3). The distance to the 

worker who was between the source and the film cassette, which is sometimes expressed in terms of 

the source-to-skin distance (SSD), was somewhat smaller and, therefore, the ESE to the worker was 

somewhat greater than the exposure at the plane of the film. PA Chest and Anterior Posterior (AP) 

Lumbar spine thicknesses were assumed to be 26 cm while the thickness of the Lateral Chest and 

Lateral Lumbar Spine was 34 cm. It further was assumed that a distance of 5 cm existed between the 

film and the closest surface of the body to the film. These measurements are reasonable and were 

used to estimate the ESEs for the various X-ray examinations for ORNL employees) [5].

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

are of four types: half-wave rectified, which were present in the earliest X-ray equipment; full-wave 

rectified; constant potential (as defined in NCRP Report 33); and high-frequency generators. A halfwave 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 

Waveform and Collimation Characteristics

 

4 Also know n as film-to-focus distance (FFD).
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 11 of 29

second, each with duration of 1/120 second. Thus, 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 the full-wave rectified type. 

Constant potential machines, as defined in NCRP Report 33, and high-frequency generators produce 

a more or less steady (i.e., unpulsed) output of X-rays and have somewhat greater beam intensity – 

approximately 10% more – than full-wave rectified machines operating at the same kVp and mA. (It 

was assumed that single phase units were used until 1990 when a high-frequency generator unit was 

procured for ORNL.) [6]

Collimation refers to the size of beam. The early philosophy 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 radiation exposure concerns, beams were collimated such that the smallest beam 

consistent with the area of interest was used, thereby limiting the area of the worker 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 made by reference to the radiograph; a 

well-collimated beam will leave a small unexposed area at the edges of the radiograph, while a poorly 

collimated beam will produce a radiograph that is exposed over all of its area. Discussions with the 

radiology technician who worked at ORNL from 1947 until recently indicated that the X-ray beams 

used at ORNL were well-collimated (Tuck 2003) and a paper (Lincoln and Gupton 1958) indicates that 

a 20 cm cone was used in the mid-1950s at ORNL to reduce secondary photons and therefore 

collimated the primary beam. Nonetheless, results given in a table (Lincoln and Gupton 1958) 

indicate that the dose conversion factors (DCFs) given in ICRP 34 for a well-collimated beam may not 

apply. Therefore DCFs for poorly collimated beams found in ORAUT-OTIB-0006, Table 4.0-1 

(ORAUT 2005), were used until a newer X-ray unit was procured in 1963. Another document from the 

same author (Lincoln and Gupton 1957) stated that “Gonad doses determined from these phantom 

measurements are probably exaggerated, as the phantom is somewhat smaller than the average 

adult.”

3.2.5

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

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

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

voltage, time, and current are known along with the amount of primary beam filtration. For 

completeness, this document mentions these factors, which are tube housing, type and speed of film, 

development procedure, screens, and grids.

Screens, Grids, and Other Factors Potentially Affecting Worker Dose

X-ray tubes used for medical radiography are typically enclosed in protective lead tube housings and 

the primary beam is emitted through a port or window in the side of the housing. Although some 

reduction of worker dose is achieved, largely through elimination of scattered radiation and improved 

collimation, the primary purpose of the diagnostic tube housing is the protection of the operator, 

unexposed X-ray film, and nearby individuals other than the worker. This issue is moot, however, 

because virtually all X-ray tubes, and certainly those used at ORNL since its inception, had protective 

tube housings.

The amount of exposure needed for a suitable radiograph is in some measure a function of film speed 

and development. Fine-grain emulsions produce a superior radiographic image but require additional 

exposure in comparison to fast films. In addition, underdevelopment of films requires additional 

exposure to achieve satisfactory radiographic quality. Intensifying screens are used in the cassette to 

augment the radiographic effect and thereby increase film speed and reduce worker dose. Grids, 

specifically the Potter-Bucky diaphragm (colloquially known as a Bucky), are sometimes utilized for 

thick-section radiography, but rarely for chest radiography except with large workers. In any case, the 
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 12 of 29

above (i.e., kVp, mA, exposure time, and filtration) are all factored into the technique used and, except 

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

reconstruction.

3.3 X-RAY DOSES TO ORNL WORKERS, 1943 TO PRESENT 

The effects of various technical factors and how they affect X-ray beam intensity are summarized in 

Table 3-1.

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

Distance d Approximately inverse square relations (1/d2)

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

The current ORNL Medical Department provided a description of radiographic procedures that have 

been used to conduct X-ray examinations for workers at the ORNL site (ORNL 2002, see Table 3-2). 

Before October 3, 1947, all radiology examinations were performed at Oak Ridge Hospital in Oak 

Ridge, Tennessee. A review of several individual records in the ORNL Medical Records vault seems 

to confirm that many early preplacement medical examinations were conducted at Oak Ridge Hospital 

from 1943 through 1947. The vault contains 4- × 10-in., stereoscopic PFG images; a sampling of 

~15% of these images indicated beginning and end dates of March 1944 and September 1945, 

respectively, for the examinations. The ESE and organ dose values in Tables 3-4 and 3-6, 

respectively, for PFG examinations are based on the assumption that stereo imaging was always 

employed for such examinations; that is, each procedure consisted of two exposures for each 

individual [7]. If it is determined that a PFG conducted for a given individual consisted of only one 4- × 

5-in. view, the values in these tables should be divided by 2. Although 14- × 17-in. radiographic PA 

chest images were in individual medical X-ray files from 1943 through 1947, the use of stereo PFG for 

preplacement examinations during that period cannot be discounted. Such examinations should be 

assumed, therefore, for each individual who began employment during that period unless there is 

evidence to the contrary [8]. Almost exclusively, individual medical files noted that retake, routine 

annual, and termination X-ray films taken from 1943 through 1947 were 14- × 17-in. radiographic PA 

chest images. [However, during the review of radiographic images archived by the ORNL medical 
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 13 of 29

Table 3-2. X-ray operating parameters, dates of use, and frequency of examinations (provided by ORNL). Dates X-ray equipment Location Exam/Projections Techniques People involved Age dependence

Prior to October 3, 

1947

Not accurately known, but 

possibly a Westinghouse 

Fluorodex 60-120 kVp

Oak Ridge 

Hospital

Stereo PFG (2 views)

for preplacement 

exams

PA chest X-ray for 

other exams

Not accurately known Employees and 

preplacement

October 3, 1947 

to end of 1963

Picker 200-mA Control & 

Generator- Model R-2 

ORNL Chest X-ray, one film, 

PA projection

Filter=0.04 mm Al

76 kVp, 200 mA @ 1/20 sec., 

183 cm. distance, w/ 20-cm cone

Employees and 

Preplacement

April 6, 1950, to 

September 23, 

1953

Picker 200-mA Control & 

Generator- Model R-2 

ORNL Lumbar spine series, 

4 films: AP, AP spot, 

Lateral, and Lateral 

spot

AP & AP spot

Filter=0.04 mm Al, 80 kVp, 40 

mA, 4 sec @ 99 cm. distance, w/ 

20-cm cone

Craft workers

LAT & LAT spot

Filter=0.04 mm Al, 86 kVp, 40 

mA, 8 sec @ 99 cm distance, w/ 

20-cm cone

End of 1963 to 

1976

Westinghouse Riviera 300 

mA, 125 kVp

ORNL Chest X-ray, one film, 

PA projection

Filter 1.5 mm Al, 107 kVp, 300 

mA, 0.01 sec, @ 183 cm 

distance

Preplacement

1976 to November 

1990

Westinghouse Riviera 300 

mA, 125 kVp

ORNL Chest X-ray, one film, 

PA projection

Filter 1.5 mm Al, 107 kVp, 300 

mA, 0.01 sec, @ 183 cm 

distance

Preplacement;

employees in 

respirator/asbestos 

programs (every 3 

years)

November 1990 to 

April 18, 1996

Bennett High Frequency 

Quartz 600 Series

ORNL Chest X-ray, one film, 

PA projection

Filter 2.0 mm Al, 110 kVp, 300 

mA, 3.2 mAs, @ 183 cm distance

Preplacement; 

respirator/asbestos 

program employees

<40 years old, every 3 

years; 40-49 years old, 

every 2 years; >49 

years old, every year

April 18, 1996 to 

2002

Bennett High Frequency 

Quartz 600 Series

ORNL Chest X-ray, two 

films, PA and lateral 

projections

PA

Filter 2.0 mm Al, 110 kVp, 300 

mA, 3.2 mAs, @ 183 cm distance

Preplacement; 

respirator/asbestos 

program employees

<40 years old, every 3 

years; 40-49 years old, 

every 2 years; >49 

Lateral years old, every year

Filter 2.0 mm Al, 125 kVp, 300 

mA, 8.0 mAs, @ 183 cm distance

2002 Bennett High Frequency 

Quartz 600 Series

ORNL Chest X-ray, two 

films, PA and lateral 

projections

PA

Filter 2.0 mm Al, 110 kVp, 300 

mA, 3.2 mAs, @ 183 cm distance

Asbestos program 

employees

Annually for workers 45 

and over 

Lateral

Filter 2.0 mm Al, 125 kVp, 300 

mA, 8.0 mAs, @ 183 cm distance
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 14 of 29

department, two stereo PFG films that were taken approximately 1 year apart were located for an 

individual. The initial PFG was followed approximately 2 weeks later with a 14- × 17-in. radiographic 

PA chest image due to problems in viewing the initial film. The medical record indicated that an 

annual chest X-ray was taken approximately 1 year after the initial PFG. This annual chest X-ray was 

a PFG examination.]

The use of PFG imaging was common during that period because it was less expensive than the 

conventional (e.g., larger) X-ray films and could quickly be used as a means of screening large 

numbers of individuals for tuberculosis, which was a public health concern at the time. Follow-up 

examinations with conventional-sized films (e.g., 14- × 17-in.) were taken as needed to either confirm 

original results or to get clearer images. 

There is an indication from documentation at Y-12 that some medical examinations were performed in 

Knoxville, Tennessee, but it is not known at what frequency these were performed or if medical X-rays 

for employment purposes for ORNL workers were ever taken in Knoxville. All X-ray films reviewed in 

the ORNL Medical Records vault were inscribed either “OR Hospital” or “Oak Ridge National Lab.” 

Nonetheless, the assumption of a 0.2-R exposure for a PA chest radiograph (ORAUT 2005) at a 

Knoxville hospital would be favorable to claimants, and the absorbed dose values in Table 3-6 can be 

used to estimate organ doses for other hospitals in the 1940s that might have performed PA chest Xray examinations [9]. (The United States Army Center for Health Protection and Preventative 

Medicine was contacted, but no historic information regarding type of equipment used, procedures, or 

equipment operating parameters was obtained nor was information that Oak Ridge Hospital even 

existed as an Army hospital.) Oak Ridge Hospital became Methodist Hospital of Oak Ridge in 1959. 

Historical records transferred from Oak Ridge Hospital to ORNL appear to have either been 

incorporated in individual medical files or remain in the X-ray pouches. Based on the gaps in time for 

the PFGs noted above, it is not clear if all medical and X-ray records were transferred from Oak Ridge 

Hospital to ORNL Medical. It is possible that records were sent to the Oak Ridge Reservation (ORR) 

site at which the employee was active at the time and were not transferred with them when they 

transferred to other ORR sites.

Information provided by the ORNL medical department indicated that from October 3, 1947, to the 

present, all medical X-rays for screening conducted in the ORNL Medical area used conventional, 

radiographic (non-PFG) equipment. A fluoroscopic unit was used at ORNL at one point for 

conducting upper gastrointestinal (GI) series examinations, but was never used for examinations that 

would be considered occupational exposure under EEOICPA. 

After ORNL stopped performing upper GI examinations (believed to be in the early 1950s), and at the 

request of K. Z. Morgan (director of ORNL’s health physics department), the radiology technician (RT) 

constructed a shield from the rubberized-lead, fluoroscopy apron that male workers could use to 

shield their gonads during routine employment screenings (Tuck 2003). (The RT added that K. Z. 

Morgan was adamant about radiation protection in medical procedures.) The RT stated that workers 

would hold the shield at approximately waist level for a PA chest exam or place it across their thighs 

for AP (or similar) exposures. It was the RT’s assertion that only male workers would use the shield, 

as it would interfere with the region of interest if females used it to shield the ovaries. The RT would 

check the shield for leaks by exposing an X-ray cassette with the shield in front of it. Use of the shield 

was discontinued (the RT could not recall when) in favor of better collimation of the X-ray beam. 

Table 3-2 lists radiographic examinations that would be considered occupational medical exposures 

as defined under EEOICPA for workers at ORNL after October 3, 1947, identifying the equipment and 

operating parameters used during the different periods. Two items in the description provided by the 

ORNL Medical Department that appear to be inconsistent for equipment in use at the time are the 
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 15 of 29

inherent (and total) filtration of the initial Picker unit and the exposure time used with the 

Westinghouse Riviera unit. Typical inherent filtration for an X-ray tube at the time was approximately 

0.5 mm Al (TM 1944), with additional filtration added to harden the beam. The reported exposure 

time of 0.01 second with a tube current of 300 mA gives a 3-mAs intensity, which is believed to be low 

for chest X-rays. Rather than using the given 0.01-sec exposure time, it is assumed that the exposure 

time was 0.1 second, making exposures for PA chest films 30 mAs when using the Picker X-ray unit. 

The radiographic examinations performed at ORNL are listed below:

• Chest: PA and lateral

• Lumbar spine series: AP, AP Spot, lateral, and lateral spot

Accordingly, only doses from these exams, in addition to the PFG exams conducted at the Oak Ridge 

Hospital from 1943 to 1947, were evaluated to support dose reconstructions at the ORNL site. Table 

3-2 lists the three radiographic machines that have been used at ORNL and the applied voltage, tube 

current, exposure time, and SID used for examinations. Medical records for individuals who worked 

at ORNL in the early years indicated that radiographic chest examinations made during the 

preplacement, routine annual, and termination physicals were the norm until the 1970s, when

individuals were able to waive annual chest X-ray examinations. [Information in the individual’s 

medical files and X-ray log books available in the ORNL Medical Records vault should enable a dose 

reconstructor to estimate the number of occupational medical X-ray examinations from October 3, 

1947 for a given individual. Information for workers who worked at the site from 1943 to October 3, 

1947, was present in many of the medical files that were reviewed. This information may be provided 

by the ORNL Medical staff for use by the dose reconstructor to determine number of examinations.]

The lumbar spine series of examinations was reserved for preplacement X-ray examinations for craft 

employees (pipefitters, carpenters, etc.) to determine if they had pre-existing back problems prior to 

hiring. The information provided by the ORNL medical department indicated that the Lumbar Spine 

series of examinations, which took place from April 6, 1950, to September 23, 1953, would have been 

conducted along with a PA chest examination. Although the spot X-ray examinations would have 

used conic or cylindrical shields to reduce the size of the field and, therefore, would have significantly 

reduced exposures to organs outside the field of view, the ESEs within the field would have been 

unlikely to change. For dose reconstruction purposes, it is assumed that two AP and two lateral 

lumbar spine examinations would have been conducted on preplacement individuals during this 

period and this is favorable to claimants. 

A review of the claim files from ORNL indicates that records often state that standard chest X-rays 

were taken in the AP direction. This is believed to be an error, as chest X-rays are almost always 

done (at least on ambulatory workers) PA. The assumption for this project, therefore, is that chest Xrays were performed PA, and not AP like some of the records state. 

Field surveys performed at the Oak Ridge Hospital in 1956 indicated that the skin exposure for a 

single exposure PA Chest PFG was 1.4 R (Gupton, Tuck and Lincoln 1956). This value was doubled 

to 2.8 R to account for a stereo (two exposure) procedure. The 2.8 R ESE value was used for the 

calculation of organ dose from PFG examinations used in preplacement screenings performed prior to 

October 3, 1947. Organ dose values provided for PFG exams should be divided by 2 if it is known 

that only a single PFG exposure was made. For retake, annual, or termination chest X-ray exams 

users should assume that standard 14- × 17-in. PA films were made unless otherwise noted in the 

medical records. Organ doses have been provided in Table 3-6 for both stereo PFG exams and 

standard PA chest exams for the period prior to October 3, 1947. 
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 16 of 29

A potential problem common to all X-ray examination procedures relates to the conversion of 

exposure represented by ESE to absorbed organ dose, and to changes in the definition of dose and 

other dose quantities. Over the 50 or so years since the beginning of ORNL operations, the quantity 

known today as exposure has undergone several important conceptual changes, as has the 

application of the unit of exposure, the roentgen (R), which in itself is obsolete. Thus, there is much 

confusion about the definition of exposure and its associated unit. At one time, the Roentgen was 

used to quantify the dose from electromagnetic radiation in air and, when this proved confusing and 

inexact, was defined as exposure dose to distinguish it from the term absorbed dose, which was 

applicable to any type of radiation.

Additional confusion was engendered by changes in the values of the conversion coefficients used to 

convert exposure to absorbed dose. At various times an exposure of 1 R was equated to a soft tissue 

dose of 0.83, 0.877, or 0.93 rad. Thus, an exposure to air of 1 R would result in an absorbed dose of 

somewhat less than 1 rad (= 1 cGy = 10 mGy). However, it was customary in radiation protection 

practice and regulation to use the units R and rad interchangeably. This resulted in an inherent 

overestimate of reported dose or dose equivalent since dosimeters were typically calibrated against a 

field measured in R. 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. Thus, to avoid any risk of dose 

underestimation, 1 R of exposure was taken to be equal to1 rad of absorbed dose and to 1 rad (10 

mGy) of kerma. 

The ESE values for each X-ray generating device and radiographic examinations used at ORNL are 

listed in Table 3-4. If site-specific measured ESE data were not obtained from the literature, ESEs

were estimated based on knowledge of the operating parameters of the X-ray tube, assumed worker 

thickness, assumed distance between worker and film, and technique used. Both Lincoln and Gupton 

documents (1957, 1958) provided measured ESE values for lumbar spine examinations conducted in 

the mid-1950s. These values were used to estimate organ doses given in Table 3-6 over the 

applicable time period. In addition, measured exposures to the testes, ovaries, and skin were used 

from this document when available. Identification and operating parameters for X-ray equipment at 

Oak Ridge Hospital in use from 1943 through October 3, 1947 were not located. However, a 1956 

survey of the Hospital’s PFG unit indicated an exposure to the skin of 1.4 R (Gupton, Tuck and 

Lincoln 1956). This value was doubled to 2.8 R to account for two PFG exposures, i.e. a stereo 

procedure. An ESE value of 0.2 R (ORAUT 2005) was used to calculate organ dose values for 

radiographic PA chest examinations performed at Oak Ridge Hospital or elsewhere during this period 

(i.e., prior to October, 1947) [10]. 

Conversions from ESEs to organ doses were done using DCFs from Tables A2 through A9 of ICRP 

Publication 34, “Protection of the Patient in Diagnostic Radiology” (ICRP 1982), where the photon 

beams were well-collimated. However, early X-ray units typically did not provide adequate collimation 

to reduce organ exposures outside the primary beam. Thus, for chest X-ray procedures performed 

prior to 1963, DCF values from Table 4.0-1 of ORAUT-OTIB-0006 (ORAUT 2005) were used to 

estimate organ doses. [Where DCF values were not provided in Table 4.0-1 (i.e., for HVLs equivalent 

to 1.5 and 2.5 mm of Al), guidance was provided by the Oak Ridge Associated Universities (ORAU) 

Team Medical X-ray Lead to estimate and verify the values used in Table 3-5 of this report.] The DCF

tables from ICRP Publication 34 provide average absorbed organ doses for specific 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 Interactive RadioEpidemiological Program (IREP) code. For organs included in IREP 

that are not specifically identified in ICRP 34, the DCFs selected were those for organs identified in 
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 17 of 29

ICRP 34 that were anatomically the closest, as specified in (ORAUT 2005). Thus, the factor for lung 

is used for other organs in the thoracic cavity (i.e., the thymus, esophagus, stomach, and liver/gall 

bladder). Because an appreciable fraction of the skeleton, in particular the trabecular bone, which 

has a large surface-to-volume ratio, is in the trunk, the DCF for lung is used to compute dose to the 

bone surfaces. For organs in the abdomen (i.e., urinary bladder and colon/rectum) the DCF for the 

ovaries is used. These surrogate organs are summarized in Table 3-7. Because, as discussed 

above, 1 R was taken to be 10 mGy (1 cGy) of kerma, conversion could easily be made if the beam 

quality was known. Measured beam quality data were not consistently found for the ORNL site and, 

therefore, data that were located were not used. The applied voltage and filtration were provided in 

the site description (and modified as noted in Table 3-3), and an estimate of beam quality was made 

from these data. Because absorbed organ dose increases as a function of HVL for a given amount of 

filtration and exposure (mAs), the upper limit on the likely beam quality was calculated and rounded 

up to match the closest value in the tables in ICRP 34 or ORAUT (2005). 

The assumed operating parameters used to calculate ESE and organ dose are listed in column 2 of 

Table 3-3. Several items were either not obtained or not clear and assumptions were necessary to be 

able to calculate organ doses. The examination type, frequency, ESEs, and HVLs used to calculate 

organ doses are listed in Table 3-4. The DCFs from ICRP 34 (1982) and ORAUT (2005) used to 

calculate organ doses are listed in Table 3-5. The calculated organ doses are listed in Table 3-6. 

ICRP 34 does not give DCFs for several organs that are inputs to IREP, so other organs were used 

as surrogates based on their positions in the body. The surrogates and associated organs are listed 

in Table 3-7. Table A6 in ICRP 34 states that DCFs were "Not computed but small compared with 

projections listed above" referring to dose to female breasts from lumbar spine exams. Therefore, the 

DCFs for the female breast from the Upper GI projections were used to estimate organ dose to the 

female breast from the lumbar spine projections, which should be favorable to claimants given the 

statement in ICRP 34. 

Table 3-3. Assumptions made to operating parameters provided by ORNL and where default 

parameters were used. 

ORNL-provided operating parameter Assumed operating parameter

PFGs were taken at Oak Ridge Hospital for a period 

prior to 1947.

All employees were assumed to have received 

preplacement stereo PFG for employment purposes 

between 1943 and October 3, 1947.

Skin exposure for the Oak Ridge Hospital was given in 

a survey conducted by ORNL Medical Staff of PFG unit 

of 1.4 R.

ESE from stereo PFG = 2.8 rem (assume 2 exposure 

views) from the Oak Ridge Hospital survey forms.

14” × 17” radiographs of chest were noted for most site 

personnel for all retakes, routine annual, and 

termination examinations unless waived.

All retakes, routine annual, and termination examinations 

had PA chest X-ray examination unless medical records 

indicate differently.

ESE from early 14” × 17” radiographs conducted at 

Oak Ridge Hospital not known.

ESE for 14” × 17” radiographs not performed at ORNL = 

0.2 rem (default)

Inherent filtration on Picker R-2 Unit = 0.04 mm Al. Review of Lincoln and Gupton (1957, 1958) indicates that 

a filtration value of 1 mm Al was used with the Picker R-2 

unit.

Total filtration for Picker R-2 unit not given. HVL = 1.5 mm Al for organ dose calculations. 

Operating parameters for Picker were 76 kVp/10 mAs 

(PA chest), 80 kVp/160 mAs (AP lumbar spine), and 86 

kVp/320 (LAT lumbar spine).

Operating parameters for Picker are 76 kVp/10 mAs (PA 

chest), 80 kVp/160 mAs (AP lumbar spine), and 86 

kVp/320 (LAT lumbar spine).

SIDs for all chest, PFG chest, and lumbar spine 

examinations were 72, 48, and 39 in., respectively.

SIDs for all chest, PFG chest, and lumbar spine 

examinations were 183, 122, and 99 cm, respectively.

Lumbar spine exams conducted on craft individuals 

from 4/6/50 to 9/23/53.

Lumbar spine exams conducted on craft individuals from 

4/6/50 to 9/23/53.
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 18 of 29

ORNL-provided operating parameter Assumed operating parameter

PA and LAT chest thicknesses and distance from body 

to imaging surface not given.

Assume PA and LAT chest thicknesses of 26 and 34 cm, 

respectively; AP and LAT LS thicknesses of 26 and 34 cm, 

respectively; and distance from body to imaging surface of 

5 cm.

Exposure time for Westinghouse Riviera was given as 

0.01 sec.

Review of equipment in use indicates that 3 mAs probably 

would have been low for that period and, therefore, 

exposure time was assumed to be 0.1 sec giving 30 mAs.

Operating parameters for Westinghouse Riviera were 

107 kVp/3 mAs (PA chest).

Operating parameters for Westinghouse Riviera were 107 

kVp/30 mAs (PA chest).

Operating parameters for Bennett are 110 kVp/3.2 mAs 

(PA chest) and 125 kVp/8 mAs (LAT chest).

Operating parameters for Bennett are 110 kVp/3.2 mAs 

(PA chest) and 125 kVp/8 mAs (LAT chest).

Filtration values were given of 3.0, 0.04, 1.5, and 2.0 

mm Al, respectively for Oak Ridge Hospital, Picker, 

Westinghouse, and Bennett units. HVL values were 

not given by ORNL.

Assume that HVL values for Oak Ridge Hospital, Picker, 

Westinghouse, and Bennett units are 2.5, 1.5 (2.0 for 

Lumbar Spine exams), 3.0, and 3.5 mm Al, respectively.

Though cone in place, measurements of organ doses 

indicate that the collimation of X-ray beam was bad for 

the Oak Ridge Hospital and Picker units.

Use DCFs for poorly collimated beams for organ dose 

estimates for the Oak Ridge Hospital and Picker units. 

Collimation of the beam for the Westinghouse and Bennett 

units is assumed to be good and ICRP 34 standard DCFs

used.

Waveform information not given for any unit. Picker R-2 and Westinghouse Riviera were single-phase 

units; Bennett unit was high-frequency.

Preplacement examinations indicated. Preplacement, retakes, routine annual, and termination Xray examinations given.

Respirator and asbestos workers had different X-ray 

examination frequencies from approximately 1976 to 

present.

Assumed frequencies for respirator and asbestos workers 

listed in Table 3-2.

Table 3-4. Values used to calculate organ dose. 

Years included Examination Workers affected ESE (rem) HVL (mm Al)

Before 1947 Stereo PFGa Preplacement 2.8E+00 2.5

Before 1947 Chest PA PFG retake, annual, and termination 2.0E-01 2.5

1947–1963 Chest PA Preplacement, annual, and termination 5.6E-02b 1.5

1950–1953 LS APc Preplacement for craft workers 4.0E+00 2.0

1950–1953 LS LATd Preplacement for craft workers 1.0E+01 2.0

1964–1990 Chest PA Preplacement, others as needed e 1.3E-01 3.0

1990–2002 Chest PA Preplacement, others as needede 2.2E-02 3.5

1996–2002 Chest LAT Preplacement, others as needede 6.2E-02 3.5

a. The ESE for the Stereo PFG represents both exposures. Values in Table 3-6 also indicate organ doses from both 

exposures.

b. Though Lincoln and Gupton (1958) indicate a measured ESE of 2.1E-02 rem, this value is low compared to expected 

exposures betw een 1947 and 1963. The ESE provided in this Table w as estimated using the equipment’s operating 

parameters. This value is approximately a factor of 2.7 greater than that measured and is favorable to claimants. 

c. The ESE for the LS A P represents both the A P and spot A P exposures (i.e., 2 exposures). Values in Table 3-6 also 

indicate organ doses from both exposures.

d. The ESE for the LS LA T represents both the LA T and spot LA T exposures (i.e., 2 exposures). Values in Table 3-6 also 

indicate organ doses from both exposures.

e. Asbestos w orkers and others involved in respiratory protection programs examined periodically (see Table 3-2).

3.4 UNCERTAINTY ANALYSIS FOR ORNL RADIOGRAPHY DOSES

Occupational medical X-ray exposures (e.g., ESEs) at ORNL were derived from measured values 

and/or equipment operating factors. Several factors can introduce uncertainties or affect the X-ray 

machine output intensity and dose to the worker. These include: 

1. Variation in applied voltage
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 19 of 29

2. Variation in tube current

3. Variation in exposure time

4. Distance from the worker to the source of the X-rays (SSD)
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 20 of 29

Table 3-5. DCFs (average absorbed dose per unit entrance air kerma) for selected X-ray projections, organs, and beam qualities.

a

Organ View b

Source-image 

distance (cm)

Image 

receptor size 

(cm)

Dose conversion 

factor (mGy per 

Gy air kerma) for 

HVL = 1.5 mm Al

Dose conversion 

factor (mGy per 

Gy air kerma) for 

HVL = 2.0 mm Al 

Dose conversion 

factor (mGy per 

Gy air kerma) for 

HVL = 2.5 mm Al 

Dose conversion 

factor (mGy per 

Gy air kerma) for 

HVL = 3.0 mm Al 

Dose conversion 

factor (mGy per 

Gy air kerma) for 

HVL = 3.5 mm Al

Thyroid

Chest PA 183 35.6 × 43.2 120 (c) -- 174c 46 62

Chest LAT. 183 35.6 × 43.2 -- -- -- -- 151

Stereo PFG 122 10.2 × 25.4 -- -- 174c -- --

LS AP 99 35.6 × 43.2 -- 0.2 -- -- --

LS LAT. 99 35.6 × 43.2 -- 0.01 -- -- --

Eye/Brain

Chest PA 183 35.6 × 43.2 11 -- 32c 46 62

Chest LAT. 183 35.6 × 43.2 -- -- -- -- 151

Stereo PFG 122 10.2 × 25.4 -- -- 32c -- --

LS AP 99 35.6 × 43.2 -- 0.2 -- -- --

LS LAT. 99 35.6 × 43.2 -- 0.01 -- -- --

Ovaries

Chest PA 183 35.6 × 43.2 N/A -- N/A 1.8 3.2

Chest LAT. 183 35.6 × 43.2 -- -- -- -- 1.6

Stereo PFG 122 10.2 × 25.4 -- -- N/A -- --

LS AP 99 35.6 × 43.2 -- N/A -- -- --

LS LAT. 99 35.6 × 43.2 -- N/A -- -- --

Testes

Chest PA 183 35.6 × 43.2 N/A -- N/A 0.01 0.01

Chest LAT. 183 35.6 × 43.2 -- -- -- -- 0.1

Stereo PFG 122 10.2 × 25.4 -- -- N/A -- --

LS AP 99 35.6 × 43.2 -- N/A -- -- --

LS LAT. 99 35.6 × 43.2 -- N/A -- -- --

Lungs (male)

Chest PA 183 35.6 × 43.2 243 -- 419 496 565

Chest LAT. 183 35.6 × 43.2 -- -- -- -- 276

Stereo PFG 122 10.2 × 25.4 -- -- 419 -- --

LS AP 99 35.6 × 43.2 -- 62 -- -- --

LS LAT. 99 35.6 × 43.2 -- 10 -- -- --

Lungs (female)

Chest PA 183 35.6 × 43.2 250 -- 451 535 610

Chest LAT. 183 35.6 × 43.2 -- -- -- -- 310

Stereo PFG 122 10.2 × 25.4 -- -- 451 -- --

LS AP 99 35.6 × 43.2 -- 62 -- -- --

LS LAT. 99 35.6 × 43.2 -- 10 -- -- --

Breast

Chest PA 183 35.6 × 43.2 18 -- 49 69 91

Chest LAT. 183 35.6 × 43.2 -- -- -- -- 316

Stereo PFG 122 10.2 × 25.4 -- -- 49 -- --

LS AP 99 35.6 × 43.2 -- 18 (d) -- -- --

LS LAT. 99 35.6 × 43.2 -- 9.5 (d) -- -- --

Uterus (embryo)

Chest PA 183 35.6 × 43.2 N/A -- N/A 2.3 3

Chest LAT. 183 35.6 × 43.2 -- -- -- -- 1.4

Stereo PFG 122 10.2 × 25.4 -- -- N/A -- --

LS AP 99 35.6 × 43.2 -- 217 -- -- --

LS LAT. 99 35.6 × 43.2 -- 20 -- -- --
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 21 of 29

Organ View b

Source-image 

distance (cm)

Image 

receptor size 

(cm)

Dose conversion 

factor (mGy per 

Gy air kerma) for 

HVL = 1.5 mm Al

Dose conversion 

factor (mGy per 

Gy air kerma) for 

HVL = 2.0 mm Al 

Dose conversion 

factor (mGy per 

Gy air kerma) for 

HVL = 2.5 mm Al 

Dose conversion 

factor (mGy per 

Gy air kerma) for 

HVL = 3.0 mm Al 

Dose conversion 

factor (mGy per 

Gy air kerma) for 

HVL = 3.5 mm Al

Bone marrow (male)

Chest PA 183 35.6 × 43.2 49 -- 92 117 146

Chest LAT. 183 35.6 × 43.2 -- -- -- -- 61

Stereo PFG 122 10.2 × 25.4 -- -- 92 -- --

LS AP 99 35.6 × 43.2 -- 24 -- -- --

LS LAT. 99 35.6 × 43.2 -- 15 -- -- --

Bone marrow (female)

Chest PA 183 35.6 × 43.2 43 -- 86 112 141

Chest LAT. 183 35.6 × 43.2 -- -- -- -- 48

Stereo PFG 122 10.2 × 25.4 -- -- 86 -- --

LS AP 99 35.6 × 43.2 -- 24 -- -- --

LS LAT. 99 35.6 × 43.2 -- 15 -- -- --

Skin (e)

Chest PA 183 35.6 × 43.2 1.28 -- 1.36 1.39 1.41

Chest LAT. 183 35.6 × 43.2 -- -- -- -- 1.41

Stereo PFG 122 10.2 × 25.4 -- -- 1.36 -- --

LS AP 99 35.6 × 43.2 -- 1.32 -- -- --

LS LAT. 99 35.6 × 43.2 -- 1.32 -- -- --

a. Dose conversion factors (DCFs) for HVLs of 1.5, 2.0, 3.0, and 3.5 mm Al are from Tables A.2 through A.9 of ICRP 34, assuming good collimation of the beam, unless otherwise 

noted. The DCFs for the 2.5 mm HVL were obtained from Table 4.0-1 of ORAUT-OTIB-0006 because data indicate that the collimation may have been questionable. “N/A” 

means dose values represent measurements rather than DCF. 

b. LS = lumbar spine.

c. Value per OTIB-0006, rev. 3 PC-1 (ORAUT 2005) assuming poor collimation of the beam. 

d. Dose conversion factors for breast for lumbar spine examination not given in ICRP 34. Values for the respective upper gastrointestinal exams (i.e., AP and LAT) were used 

instead. 

e. Values are dimensionless backscatter factors from Table B.8 of NCRP 102 (1989). Values for HVLs = 2.5 and 3.5 were obtained via linear interpolation. 
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 22 of 29

Table 3-6. Organ dose estimates for ORNL chest and lumbar spine radiographs to be used as IREP inputs.

a

Organ View

Organ dose (rem) 

prior to 1947

Organ dose (rem) 

1947–1963

Organ dose (rem) 

1950–1953 (b)

Organ dose (rem) 

1964–1990

Organ dose (rem) 

1990–present

Organ dose (rem) 

1996–present

Thyroid Chest PA 3.48E-02 6.72E-03 -- 5.98E-03 1.36E-03 1.36E-03

Chest LAT. -- -- -- -- -- 9.36E-03

Stereo PFG 4.87E-01 (d) -- -- -- -- --

LS A P -- -- 8.00E-04 (d) -- -- --

LS LA T. -- -- 1.00E-04 (d) -- -- --

Eye/Brain Chest PA 6.40E-03 6.16E-04 -- 5.98E-03 1.36E-03 1.36E-03

Chest LAT. -- -- -- -- -- 9.36E-03

Stereo PFG 8.96E-02 (d) -- -- -- -- --

LS A P -- -- 8.00E-04 (d) -- -- --

LS LA T. -- -- 1.00E-04 (d) -- -- --

Ovaries Chest PA 2.5E-02 (c) 5E-03 (f) -- 2.34E-04 7.04E-05 7.04E-05

Chest LAT. -- -- -- -- -- 9.92E-05

Stereo PFG 2.5E-02 (c) (g) -- -- -- -- --

LS A P -- -- 1.12E+00 (d) (f) -- -- --

LS LA T. -- -- 1.52E+00 (d) (f) -- -- --

Testes Chest PA 5.0E-03 (c) 2E-03 (f) -- 1.30E-06 2.20E-07 2.20E-07

Chest LAT. -- -- -- -- -- 6.20E-06

Stereo PFG 5.0E-03 (c) (g) -- -- -- -- --

LS A P -- -- 5.40E-02 (d) (f) -- -- --

LS LA T. -- -- 1.12E-01 (d) (f) -- -- --

Lungs (male) Chest PA 8.38E-02 1.36E-02 -- 6.45E-02 1.24E-02 1.24E-02

Chest LAT. -- -- -- -- -- 1.71E-02

Stereo PFG 1.17E+00 (d) -- -- -- -- --

LS A P -- -- 2.48E-01 (d) -- -- --

LS LA T. -- -- 1.00E-01 (d) -- -- --

Lungs (female) Chest PA 9.02E-02 1.40E-02 -- 6.96E-02 1.34E-02 1.34E-02

Chest LAT. -- -- -- -- -- 1.92E-02

Stereo PFG 1.26E+00 (d) -- -- -- -- --

LS A P -- -- 2.48E-01 (d) -- -- --

LS LA T. -- -- 1.00E-01 (d) -- -- --

Breast Chest PA 9.80E-03 1.01E-03 -- 8.97E-03 2.00E-03 2.00E-03

Chest LAT. -- -- -- -- -- 1.96E-02

Stereo PFG 1.37E-01 (d) -- -- -- -- --

LS A P -- -- 7.20E-02 (d) -- -- --

LS LA T. -- -- 9.50E-02 (d) -- -- --

Uterus (embryo) Chest PA 2.5E-02 (c) 5E-03 (f) -- 2.99E-04 6.60E-05 6.60E-05

Chest LAT. -- -- -- -- -- 8.68E-05

Stereo PFG 2.5E-02 (c) (g) -- -- -- -- --

LS A P -- -- 8.68E-01 (d) -- -- --

LS LA T. -- -- 2.00E-01 (d) -- -- --

Bone marrow (male) Chest PA 1.84E-02 2.74E-03 -- 1.52E-02 3.21E-03 3.21E-03
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 23 of 29

Organ View

Organ dose (rem) 

prior to 1947

Organ dose (rem) 

1947–1963

Organ dose (rem) 

1950–1953 (b)

Organ dose (rem) 

1964–1990

Organ dose (rem) 

1990–present

Organ dose (rem) 

1996–present

Chest LAT. -- -- -- -- -- 3.78E-03

Stereo PFG 2.58E-01 (d) -- -- -- -- --

LS A P -- -- 9.60E-02 (d) -- -- --

LS LA T. -- -- 1.50E-01 (d) -- -- --

Bone marrow (female) Chest PA 1.72E-02 2.41E-03 -- 1.46E-02 3.10E-03 3.10E-03

Chest LAT. -- -- -- -- -- 2.98E-03

Stereo PFG 2.41E-01 (d) -- -- -- -- --

LS A P -- -- 9.60E-02 (d) -- -- --

LS LA T. -- -- 1.50E-01 (d) -- -- --

Skin (d) Chest PA 2.72E-01 7.17E-02 -- 1.81E-01 3.10E-02 3.10E-02

Chest LAT. -- -- -- -- -- 8.74E-02

Stereo PFG 3.81E+00 (d) -- -- -- -- --

LS A P -- -- 5.28E+00 (d) -- -- --

LS LA T. -- -- 1.32E+01 (d) -- -- --

a. The exposures for various date ranges should be matched to the X-ray examinations listed in Table 3-2. 

b. Applies only to preplacement exams for craft workers between 1950 and 1953. In these cases dose from the lumbar exams should be included with that from a PA chest exam 

for the period 1947 – 1963.

c. Default value from OTIB-0006, Rev. 3 PC-1 (ORAUT 2005).

d. Value is doubled to account for two exposures.

e. Skin dose values include backscatter factors from Table B.8 of NCRP 102 (1989).

f. Organ dose values for the testes and ovaries for lumbar spine views for 1950 – 1953 are measurements reported in Tables III and IV of Lincoln and Gupton (1957).

g. The value is not doubled because this organ should not have been in the primary beam. The value from OTIB-0006 is expected to be favorable to the claimant without the need 

to double it.
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 24 of 29

Table 3-7. Surrogate and associated organs. 

Surrogate Associated organs

Lung Thymus, esophagus, stomach, liver, gall bladder, 

spleen, remainder, and bone surface

Ovaries Urinary/bladder and colon & rectum

The influence of such other factors as use of screens, grids, reciprocity failure, film speed, and 

development, while potentially variable, would not affect the beam output intensity.

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

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

focal spot loading occurs, as might be the case if the power rating of the machine is exceeded. It is 

unlikely that power ratings were ever exceeded because such an event would be difficult to achieve in 

practice and could result in damage to the X-ray tube. However, even with the use of constant 

voltage transformers to control line voltages, slight variations might occur in line voltage input or other 

internal voltage of the machine. In general, for a given applied voltage setting, variation in kVp falls 

within ±5% (Seibert, Barnes, and Gould 1991). As noted above, beam intensity is approximately 

proportional to the 1.7 power of the applied voltage; this translates to an uncertainty of approximately 

±8.6% with respect to output beam intensity in the 80 to 100 kVp. For conservatism, this is rounded 

up to ±9%.

Similarly slight variations in tube current are normal. As a tube ages, or heats from use, current can 

change and typically will drop. With all other factors 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 are 

readily detectable 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 such temporary measures were ever necessary or applied at 

ORNL. For a given kVp setting, the output of the beam is a function of the tube current, which in turn 

is measured by a milliammeter, which measures average tube current. The measurement is subject 

to uncertainties. There might be minor changes in output as the tube heats from normal use. 

Because these variations are typically small, the estimated uncertainty in beam output attributable to 

current variation is ±5% [11]. 

Another parameter that has the potential to affect dose from a radiographic procedure, perhaps 

significantly, relates to the time of exposure. A full-wave-rectified machine produces 120 pulses per 

second of X-rays. In an exposure time of 1/20 of a second, 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. Accuracy improved significantly with the 

introduction of electronic timers. Nonetheless, the uncertainty in beam output attributable to timers 

was assumed to have an upper limit of ±25%. 

The final factor likely to affect worker dose relates to the distance of the worker from the source of the 

X-rays, which is a determinant of the ESE. For a given individual, the SSD will be determined largely 

by the body thickness of the worker and the accuracy of the positioning. For a typical worker, the 

estimated variation in SSD is no more than a few centimeters, with an upper limit of perhaps 7.5 cm. 

Using the inverse square of the distance, this indicates an uncertainty of ±10% from this source [12].

The combined uncertainty from the five potential sources described above was estimated by 

assuming that the uncertainties are random and computing the root mean square (RMS) value. The 
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 25 of 29

RMS value is simply the square root of the sum of the squares and computes as ±28.8%. Rounding 

this value up to ±30% would seem convenient and favorable to the claimant [13]. 

3.5 ATTRIBUTIONS AND ANNOTATIONS

Where appropriate in this document, bracketed callouts have been inserted to indicate information, 

conclusions, and recommendations provided to assist in the process of worker dose reconstruction. 

These callouts are listed here in the Attributions and Annotations section, with information to identify 

the source and justification for each associated item. Conventional References, which are provided in 

the next section of this document, link data, quotations, and other information to documents available 

for review on the Project’s Site Research Database.

Kenny Fleming served as the initial Subject Expert for this document. Mr. Fleming was previously 

employed at ORNL and his work involved management, direction, or implementation of radiation 

protection and/or health physics program policies, procedures, or practices in relation to atomic 

weapons activities at the site. This revision and earlier revisions have been overseen by a Document 

Owner who is fully responsible for the content, including all findings and conclusions. In all cases 

where such information or previous studies or writings are included or relied on by Mr. Fleming, those

materials are fully attributed to the source. 

[1] Burns, Robert E. Shonka Research Associates. Senior Health Physicist. April 2007. 

The 0.04 mm Al total beam filtration asserted by the ORNL Medical Department appears to be 

in error because the cited total filtration is less than typical inherent filtration. A typical beam 

quality with an HVL of 1.5 mm Al was therefore assumed.

[2] Thomas, Elyse M. Oak Ridge Associated Universities. Principal Dosimetrist. April 2007. 

Given the low asserted value, the ESE was estimated using operating parameters.

[3] Burns, Robert E. Shonka Research Associates. Senior Health Physicist. April 2007. 

This conclusion was drawn from an examination of worker medical records at ORNL. 

[4] Burns, Robert E. Shonka Research Associates. Senior Health Physicist. April 2007. 

This conclusion was drawn from an examination of worker medical records at ORNL.

[5] Thomas, Elyse M. Oak Ridge Associated Universities. Principal Dosimetrist. April 2007. 

These dimensions reflect central tendencies for these variables. 

[6] Burns, Robert E. Shonka Research Associates. Senior Health Physicist. April 2007. 

It is unlikely that the previous units were constant potential.

[7] Burns, Robert E. Shonka Research Associates. Senior Health Physicist. April 2007. 

The assumption of two exposures per examination was made to ensure results that are 

favorable to the claimant.

[8] Burns, Robert E. Shonka Research Associates. Senior Health Physicist. April 2007. 

This assumption was selected to ensure results that are favorable to the claimant.

[9] Burns, Robert E. Shonka Research Associates. Senior Health Physicist. April 2007. 

The 0.2-rem ESE value from OTIB-0006 (ORAUT 2005) and Table 3-4 should be favorable to 

the claimant for any PA chest examinations before 1947; therefore, the values in Table 3-6 are 
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 26 of 29

favorable for PA chest examinations performed in Knoxville or elsewhere. The 0.2 rem ESE 

value is derived from general medical literature of that time. 

[10] Burns, Robert E. Shonka Research Associates. Senior Health Physicist. April 2007. 

The 0.2-rem ESE value from OTIB-0006 (ORAUT 2005) is derived from general medical 

literature of that time. Organ dose values computed using this value should be favorable to 

the claimant for any PA chest examinations performed prior to October, 1947. 

[11] Burns, Robert E. Shonka Research Associates. Senior Health Physicist. April 2007. 

An uncertainty of ±5% should encompass any real variability in tube current.

[12] Burns, Robert E. Shonka Research Associates. Senior Health Physicist. April 2007. 

The assumption of a 7.5-cm SSD variation, which is at the upper end of any variation that 

would be expected to occur with the use of prudent technique, was selected to ensure

favorability to the claimant. 

[13] Burns, Robert E. Shonka Research Associates. Senior Health Physicist. April 2007. 

Selection of the RMS value of uncertainty reflects accepted practice.
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 27 of 29

REFERENCES

BRH (Bureau of Radiological Health), 1970, Radiological Health Handbook, Revised Edition, U.S. 

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

Halliburton, R. E., 1985, “X-10 Medical X-ray Compliance Survey results,” September 10, 1985.

Handloser, J. S., and R. A. Love, 1951, “Radiation Doses from Diagnostic X-Ray Studies,” Radiology, 

volume 57, pp. 252–254. [SRDB Ref ID: 13354]

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

Diagnostic Radiology, Publication 34, Pergamon Press, Oxford, England.

ICRU (International Commission on Radiation Units and Measurements), 1937, “Recommendations of 

the International Committee for Radiological Units,” Fifth International Congress of Radiology, 

Radiology, volume 29, p. 634.

ICRU (International Commission on Radiation Units and Measurements), 1998, Fundamental 

Quantities and Units for Ionizing Radiation, Report 60, Bethesda, Maryland.

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

UCRL-14151, University of California, Livermore, California. [SRDB Ref ID: 26819]

Lincoln, T. A., and E. D. Gupton, 1957, "Radiation Doses in Diagnostic X-Ray Procedures,” 

Radiology, volume 71, pp. 208–215. [SRDB Ref ID: 11099]

Lincoln, T. A. and E. D. Gupton, 1958, “Radiation Dose to Gonads from Diagnostic X-Ray Exposure,” 

The Journal of the American Medical Association, volume 166, pp. 233–239, January 18.

NBS (National Bureau of Standards), 1936, X-Ray Protection, Handbook 20, U.S. Department of 

Commerce, Washington, D.C. 

NBS (National Bureau of Standards), 1949, Medical X-Ray Protection up to Two Million Volts, 

Handbook 41, U.S. Department of Commerce, Washington, D.C., March 30.

NBS (National Bureau of Standards), 1955, X-Ray Protection, Handbook 60, U.S. Department of 

Commerce, Washington, D.C.

NCRP (National Council on Radiation Protection and Measurements), 1968, Medical X-Ray and 

Gamma-Ray Protection for Energies Up To 10 MeV: Equipment Design and Use: 

Recommendations of the National Council on Radiation Protection and Measurements, Report 

33, Washington, D.C.

NCRP (National Council on Radiation Protection and Measurements), 1985, SI Units in Radiation 

Protection and Measurement, Report 82, Bethesda, Maryland.

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 102, Bethesda, Maryland.
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NIOSH (National Institute for Occupational Safety and Health), 2006, External Dose Reconstruction 

Implementation Guideline, OCAS-IG-001, Rev. 2, Office of Compensation Analysis and 

Support, Cincinnati, Ohio, August 25.

Ohnesorge, W. F., “Exposures Received from Typical Diagnostic X-Ray Examinations at ORNL and 

Safety Review of the Medical X-Ray Facility,” March 12, 1979.

ORAUT (Oak Ridge Associated Universities Team), 2005, Dose Reconstruction from Occupationally 

Related Diagnostic X-Ray Procedures, ORAUT-OTIB-0006, Rev. 03 PC-1, Cincinnati, OH, 

December 21. 

ORNL (Oak Ridge National Laboratories), 2002, ORNL Historical X-Ray Practices and Protocols, Oak 

Ridge, Tennessee. [SRDB Ref ID: 10114]

Sante, L. R., 1946, Manual of Roentgenological Technique, 13th Revised Edition, Edwards Brothers, 

Ann Arbor, Michigan.

Seibert, J. A., G. T. Barnes, and R. G. Gould, editors, 1991, Specification, Acceptance Testing and 

Quality Control of Diagnostic X-Ray Imaging Equipment, Medical Physics Monograph No. 20, 

American Association of Physicists in Medicine, American Institute of Physics, New York, New 

York. [SRDB Ref ID: 465]

Taylor, L. S., 1957, “Practical Suggestions for Reducing Radiation Exposure in Diagnostic 

Examinations,” American Journal of Roentgenology, Radium Therapy, and Nuclear Medicine, 

volume 78, number 6, pp. 983–987. [SRDB Ref ID: 13353]

TM (Technical Manual), 1944, Military Roentgenology, TM 8-280, December 30.

Trout, E. D., J. P. Kelley, and G. A. Cathey, 1952, “The Use of Filters to Control Radiation Exposure 

to the Patient in Diagnostic Roentgenology,” American Journal of Roentgenology, Radium 

Therapy, and Nuclear Medicine, volume 67, number 6, pp. 946–963. [SRDB Ref ID: 13358]

Tuck, T. L., 2003, personal conversation, September 2003.
Document No. ORAUT-TKBS-0012-3 Revision No. 02 Effective Date: 10/01/2007 Page 29 of 29

GLOSSARY

beam quality

The beam quality is used to describe the “hardness” of the X-ray beam. Hardness is 

increased by inserting filtration (typically aluminum) between the X-ray source and subject. 

Hardening the beam removes low-energy photons, thereby reducing the patient’s skin 

exposure, while preserving the higher-energy photons needed for imaging. 

collimation

Was used to focus and minimize the secondary and scattered photons that may irradiate other 

organs that are not important for diagnosis. A 20-cm cone was used early at ORNL to reduce 

this scatter. 

photofluorography (PFG)

A chest X-ray examination given at the Oak Ridge Hospital prior to X-ray equipment being 

acquired and used at ORNL. The PFG films seen at ORNL were 4” × 10” films showing two 

chest films that could be reviewed by a radiologist to see 3-D views of an individual’s chest. 

The films were not X-ray films but were captured by taking two pictures with a camera of an 

image-intensifying screen.

termination examination

A medical examination provided upon an employee’s release from ORNL.