ORAU TEAM

Dose Reconstruction

Project for NIOSH

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

Page 1 of 23

Document Title:

Y-12 National Security Complex – Occupational 

Medical Dose

Document Number: ORAUT- TKBS-0014-3 

Revision: 01

Effective Date: 06/18/2007

Type of Document: TBD

Supersedes: Revision 00

Subject Expert(s): William E. Murray

Site Expert(s): N/A

Approval: Richard Merrill Signature on File for Approval Date: 06/04/2007

William E. Murray, Document Owner

Concurrence: Signature on File Concurrence Date: 05/30/2007

John M. Byrne, Task 3 Manager

Concurrence: Signature on File Concurrence Date: 05/29/2007

Edward F. Maher, Task 5 Manager

Concurrence: Signature on File Concurrence Date: 05/31/2007

Kate Kimpan, Project Director

Approval: Brant A. Ulsh Signature on File for Approval Date: 06/18/2007

James W. Neton, Associate Director for Science

 New Total Rewrite Revision Page Change

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

REVISION AND DISCARD / DESTROY ALL COPIES OF THE PRIOR REVISION.
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 2 of 23

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION 

NUMBER DESCRIPTION

12/15/2003 00 New technical basis document for the Y-12 National Security Site –

Occupational Medical Dose. First approved issue. Initiated by William 

E. Murray.

09/09/2004 00 PC-1 Deletes references to Kathren et al., to be published on pages 7, 11, 

17 and 18. This document has not been published. Adds references 

on pages 7, 11, 17 and 18 for ORAU (Oak Ridge Associated 

Universities) 2003, Technical Information Bulletin: Dose Reconstruction 

from Occupationally Related Diagnostic X-ray Procedures, ORAUTOTIB-0006 Rev 00, Oak Ridge, Tennessee. November 14, 2003. First 

approved page change revision. Initiated by William E. Murray. 

Approval:

Signature on File_________________________________ William E. Murray, TBD Team Leader09/08/2004

Signature on File_________________________________ Judson L. Kenoyer, Task 3 Manager08/27/2004

Signature on File_________________________________ Richard E. Toohey, Project Director08/30/2004

Signature on File_________________________________ James W. Neton, Associate Director for Science09/09/2004

10/11/2005 00 PC-2 Page change initiated to incorporate the definition of U.S.C. on page 4 

and details for the definition of a DOE facility on page 5. No sections 

were deleted. Second approved page change revision. Retraining is 

not required. Initiated by William E. Murray. Approval:

William E. Murray, TBD Team Leader

Signature on File_________________________________10/06/2005 

Judson L. Kenoyer, Task 3 Manager

Signature on File _____________ ________________10/04/2005 

Richard E. Toohey, Project Director

Signature on File____________ ________________10/04/2005 

James W. Neton, Associate Director for Science

Signature on File______________ ________________10/11/2005 
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 3 of 23

04/18/2006 00 PC-3 Page change initiated to revise text in Table 3-5 on page 10 in Section 

3.4 to remove reference that uterus is a surrogate for ovaries. No 

changes occurred as a result of formal internal review. No sections 

were deleted. Text on page 10 was revised in response to NIOSH 

formal review. Third approved page change revision. Retraining is not 

required. Initiated by William E. Murray. Approval:

William E. Murray, TBD Team Leader

Signature on File__________________ ______________04/17/2006 

John M. Byrne, Task 3 Manager

Judson L. Kenoyer Signature on File for ______________04/17/2006 

Edward F. Maher, Task 5 Manager

Signature on File _________________________________04/14/2006

Kate Kimpan, Project Director

Signature on File____________ __ ______________04/18/2006 

James W. Neton, Associate Director for Science

Signature on File______________ __ ______________04/18/2006 

06/18/2007 01 Approved revision initiated to add Attributions and Annotations section 

and additional references in response to review. Added a Purpose and 

Scope subsection to the Introduction (Section 3.1). Incorporates 

formal internal and NIOSH review comments. This revision results in 

no change to the assigned dose and no PER is required. Training 

required: As determined by the Task Manager. Initiated by William E. 

Murray.
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 4 of 23

TABLE OF CONTENTS

SECTION TITLE

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

PAGE

6

3.1 Introduction ..............................................................................................................................7

3.1.1 Purpose.....................................................................................................................8

3.1.2 Scope ........................................................................................................................8

3.2 Examination Frequencies.........................................................................................................8

3.3 Equipment And Techniques .....................................................................................................9

3.4 Organ Dose Calculations ....................................................................................................... 10

3.5 Uncertainty.............................................................................................................................12

3.6 Attributions And Annotations .................................................................................................. 14

References ........................................................................................................................................15

Glossary ............................................................................................................................................16

ATTACHMENT A, OCCUPATIONAL MEDICAL DOSE .....................................................................19

A.1 Y-12 Medical X-Ray Program................................................................................................. 20

A.2 Dose Reconstructor Instructions............................................................................................ 20

A.2.1 Assignment of Organ Doses from X-ray Procedures: Maximizing 

 Approach for Dose Reconstructions ....................................................................... 20

A.2.2 Assignment of Organ Doses from X-ray Procedures: Best 

 Estimate Approach for Dose Reconstructions......................................................... 20
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 5 of 23

LIST OF TABLES

TABLE TITLE

3-1 Frequency of occupational chest x-rays at Y-12.......................................................................

PAGE

9

3-2 Description of the X-ray equipment used at Y-12 ................................................................... 10

3-3 Technique factors used for each type of X-ray equipment...................................................... 10

3-4 Entrance kerma values for Y-12 chest x rays ......................................................................... 11

3-5 Analogues for Interactive RadioEpidemiological Program (IREP) organs 

not included in ICRP (1982) ................................................................................................... 12

A-1 Frequency of occupational chest x-rays at Y-12..................................................................... 20

A-2 Organ doses (rem) for a beam quality (HVL) of 2.5 mm Al and 80 kVp 

(1943-1947) ...........................................................................................................................22

A-3 Organ doses (rem) for a beam quality (HVL) of 2.5 mm Al and 80 kVp 

(1948-1968) assuming no collimation..................................................................................... 22

A-4 Organ doses (rem)a for a beam quality (HVL) of 2.5 mm Al and 80 kVp 

(1969-January 1982).............................................................................................................. 23

A-5 Organ doses (rem)a for a beam quality (HVL) of 3.5 mm Al and 110 kVp 

(January 1982-present).......................................................................................................... 23
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 6 of 23

 ACRONYMS AND ABBREVIATIONS

Al aluminum

C.F.R. Code of Federal Regulations

cGy centigray

DCF dose conversion factor

DOE U. S. Department of Energy

eq. equivalent

ESE entrance skin exposure

GE General Electric

Gy gray

HVL half value layer

ICRP International Commission on Radiological Protection

IREP Interactive Radio-Epidemiological Program

keV kiloelectronvolt

kVp kilovolts peak

mA milliampere

MeV megaelectronvolt

mGy milligray

mm millimeter

NCRP National Council on Radiation Protection and Measurements

ORAU Oak Ridge Associated Universities

ORAUT Oak Ridge Associated Universities Team

PA posterior/anterior

PFG photofluorographic

POC probability of causation

RMS root-mean-square

s second

SID source-to-image distance

SSD source-to-skin distance

TBD technical basis document

TEC Tennessee Eastman Corporation

U.S.C. United States Code

Y-12 Y-12 National Security Complex
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 7 of 23

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-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 8 of 23

The Y-12 Plant, now known as the Y-12 National Security Complex, required pre-placement and 

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

examinations typically included chest X-rays to screen for disease. The doses from these X-ray

procedures depended not only on the characteristics of the X-ray machine and the technical factors

used, but also on the frequency of the examination. This section is based primarily on information 

provided by the staff at the present Y-12 Medical X-ray Department (Wiley 2002).

For evaluating Probability of Causation (POC), the doses to be included in calculating the worker’s 

dose are those from X-rays that are required by the employer for screening and as a condition of 

employment, e.g., X-rays taken for pre-employment, pre-placement, or routine physical examinations

(42 C.F.R. pts. 81 and 82). These X-rays are referred to in this Technical Basis Document (TBD) as 

occupational X-rays. Doses from X-rays taken by either the employer or an off-site health care 

provider for on-the-job or off-the-job injuries or illnesses are not included in the worker’s dose 

calculation for POC (42 CFR 81 and 82). 

3.1.1

This TBD documents historical occupational medicine practices at the Y-12 Plant and provides 

information needed for the reconstruction of occupational medical doses for workers.

Purpose

3.1.2

This TBD contains supporting documentation to assist in the evaluation of occupational external X-ray

doses from employer-required chest X-rays of workers at the Y-12 Plant. The objective of this 

document is to provide supporting technical medical X-ray equipment data to reconstruct the 

occupational medical doses from these X-rays using assumptions that are favorable to the claimant.

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 3.6.

3.2 EXAMINATION FREQUENCIES

The frequency of exams differed significantly over the years. The frequency of chest X-rays is shown 

in Table 3-1 for different age groups and for specific groups of workers through the years based on 

information provided by Y-12 (Wiley 2002). 

However, occupational X-rays may have occurred more frequently than on the schedule indicated in 

Table 3-1 at least in the early years. Wolf specified more frequent physical examinations (including Xray) for various occupational groups (Wolf 1945). A recommended procedure for post-employment, 

routine medical examinations specified more frequent X-rays for the following occupational groups: 

• Food handlers and cafeteria workers – every 6-12 months

• Alpha (calutron) workers – twice per year

• Liquid phase workers exposed to uranium, phosgene, or carbon tetrachloride – three times per 

year [1]. 

Information on employer-required medical X-rays may be available in the energy employee’s file.
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 9 of 23

Table 3-1. Frequency of occupational posterior/anterior chest X-rays at Y-12 (Wiley 2002)a. 

Period Frequency Comment

1943 to

July 17, 1988

Pre-placement All employees

Annually All employees

At termination All employees

July 18, 1988 to

June 30, 1993

Pre-placement All employees

Time of entry into 

hazardous job

Asbestos and beryllium workers and other jobs with 

potential pulmonary pathogens

Annually Active and previous asbestos and beryllium workers

Every 10 years Employees under 30 years old

Every 5 years Employees aged 30-45 years old

Every 3 years Employees over 45 years old

At termination All employees

July 1, 1993 – 

March 1998

Pre-placement All employees

Time of entry into 

hazardous job

Asbestos and beryllium workers and other jobs with 

potential pulmonary pathogens

Annually Active and previous asbestos and beryllium workers

At termination All employees

March 1998 – 

Present

Pre-placement All employees

Time of entry into 

hazardous job

Asbestos and beryllium workers and other jobs with 

potential pulmonary pathogens

Annually Active asbestos workers

Every 3 years Previous asbestos workers; active and previous beryllium 

workers

At termination All employees

a. Workers in certain occupations may have received chest X-rays more frequently. This information may be in the 

energy employee’s file provided by DOE.

3.3 EQUIPMENT AND TECHNIQUES

The medical practices used at Y-12 are assumed to have followed the adoption of standards of 

radiology practice during the 1930s and 1940s to minimize dose to the patient (ORAUT 2005). 

However, there is the potential for significant dose from occupational medical X-ray examinations, 

depending on the type of equipment, the technique factors, the number of photofluorographic (PFG) 

examinations typical in the early years, and the number of radiographic examinations (Cardarelli et al. 

2002). 

According to information provided by the Y-12 Medical X-Ray Department, pre-employment chest Xrays were always taken with a conventional medical diagnostic X-ray machine (Wiley 2002). They 

found no evidence of PFG chest X-rays in the employee medical X-ray folders and all chest X-rays in 

these folders were 14”x17” films. However, in reviewing the medical X-ray folders of workers from the 

1940s, approximately 1400 4”x10” chest X-ray films were found in the medical X-ray folders of 

workers who were employed at Y-12 from 1943 to 1947 (Beck 2003) [1]. Originally these X-rays were 

thought to be copies of conventional X-rays that were taken elsewhere and sent to Y-12 when the 

person was hired there. In fact, these were PFG chest X-rays.

In February 1945, a General Electric (GE) stereoscopic photoroentgen unit is listed as an equipment 

item in the Y-12 Medical Department (Wolf 1945). Reexaminations and other chest films were done 

on conventional 14”x17” films. On October 12, 1945, the Tennessee Eastman Corporation (TEC) 

Medical Director sent a telegram to the GE X-Ray Corporation, requesting them to set up a 

Photoroentgen Unit 4x10 (Leggo 1945). In June 1946, TEC placed an order with the Oak Ridge 

Hospital for 6000 Eastman-Single Coated 4”x10” X-ray films for the period from August 1, 1946 to July 

31, 1947 (Graham 1946). Thus, it is clear that pre-employment chest X-rays were taken with a PFG 
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 10 of 23

unit from 1943 to 1947, as evidenced by the 4”x10” films found in the medical records and the 

purchasing records mentioned above. All chest X-rays done since then are conventional 14”x17” Xrays. 

No record has been located to determine what type of X-ray machine was in use at Y-12 from 1948 

until the GE-type machine mentioned above that was used in the early 1960s. This date may not be 

correct either. In a meeting with the X-ray technologist who provided the information for that report, 

the technologist said that more recent documentation indicated that the GE-type machine was 

installed in 1969, not in the early 1960s (Beck 2003). Thus, it is not possible at this time to state with 

certainty what X-ray machine was used from 1948 to 1968. From 1969 until January 1982, the X-ray

machine in use was similar to a GE Model DXD-350. This machine was replaced with a GE Model 

DSX-650II in February 1982 (Wiley 2002). 

A description of the X-ray equipment used at Y-12 is included in Table 3-2. The specific technique 

factors for these machines are shown in Table 3-3. Since no technique factors were identified by Y12 for Types I and II equipment, organ doses, based on assumed technique factors, were developed 

on the basis of X-ray techniques contemporary with the time period (1943-1968), with due 

consideration given to favorability to claimants (ORAUT 2005). 

Table 3-2. Description of the X-ray equipment used at Y-12 [2]. 

Machine Time period Equipment

Type I 1943 to 1947 Photofluorographic unit at Oak Ridge Hospital or Y-12 Clinic

Type II 1948 to 1968 Unknown

Type III 1969 to January 1982 Similar to General Electric Model DXD-350 (exact model unknown)a

Type IV February 1982 to present General Electric DSX 650 II a

a.) From Wiley 2002

Table 3-3. Technique factors used for each type of X-ray equipmenta. 

Machine Projection

Current

(milliampere 

[mA])

Voltage

(kilovolts peak [kVp]) 

Exposure time

(second [s]) 

Type I X-rays were done at Oak Ridge Hospital or Y-12. Techniques are unknown. 

No records have been located. 

Type II NAb NA NA NA

Type III PAc 200 80 1/20 b

Type IV PA 200 110 Photo-timed b

a.) From Wiley 2002.

b.) NA denotes not available.

c.) PA indicates a posterior/anterior projection; the average PA chest measures 26 cm.

3.4 ORGAN DOSE CALCULATIONS

Most Y-12 employees received occupationally-related X-rays annually for many years and at a lesser 

frequency in the later years. The frequency over time (1943-present) for various groups of workers is 

shown in Table 3-1. Only the PFG chests (from 1943-1947) and the posterior/anterior (PA) chest 

projections from 1969 to the present are documented. No evidence was found that other screening Xrays were performed.

No actual X-ray output measurements are available. The X-ray technique factors provided may not 

be reliable, especially for the Type II equipment. Thus, default values for entrance kerma will be used 

in the calculation of organ dose for use in dose reconstruction. Default values have been developed 

for the three of the most commonly used occupational medical X-ray procedures: PA, lateral; and
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 11 of 23

PFG chest films (ORAUT 2005). The default values are considered to be maxima developed from 

reviews of patient doses reported in the literature, machine characteristics, and knowledge of X-ray

procedures used during the time periods indicated. Sufficient conservatism was included in the 

determination of the default values to ensure with near certainty (>99% confidence) that the actual 

exposures from the specified procedures would not exceed the default values, thus ensuring 

favorability to claimants (ORAUT 2005). 

In determining the default factors in Table 3-4, it was assumed that minimum filtration was used, along 

with low kilovolt peak (kVp) techniques, slow film speeds with standard development procedures, and 

no additional collimation or use of cones (ORAUT 2005). The default entrance kerma values for the 

three procedures are given in Table 3-4 below.

Table 3-4. Entrance kerma values for Y-12 chest X-rays. 

Period

Entrance kerma (centigray [cGy])

a

Posterior/anterior Photofluorographic

Pre-1970 0.20 3.0

1970-1985 0.10

Post 1985 0.05

a. ORAUT 2005. 

A source-to-image distance (SID) of 72 inches (in) (183 centimeter [cm]) was standard for the time for 

the PA chest, and 42 in (106 cm) for the PFG chests (ORAUT 2005). The X-ray machines used at Y12 were most likely single-phase, and typically no air gap was used between the worker and the film

(ORAUT 2005). Before 1982, it is assumed that the X-ray equipment was operated at 80 kVp, had at 

least 1.5 millimeters (mm) aluminum (Al) total filtration (see Table 3.1 of National Council on Radiation 

Protection and Measurements [NCRP] [1989]), and that the half value layer (HVL) was approximately 

2.5 mm Al equivalent [eq.] (see Table B.2 of NCRP [1989]). These were typical machine parameters 

for chest X-rays performed in this time period (ORAUT 2005). 

After 1982, the X-ray equipment was operated at 110 kVp and had at least 2.5 mm Al total filtration. 

The HVL was approximately 3.5 mm Al eq. After 1982, the machine parameters were the same but 

the exposures were photo-timed (Wiley 2002). The default values for entrance kerma were also used 

for the PA chest X-rays after 1982 because the exposure time would not be known for a photo-timed

(automatic) exposure.

The following formula was used to calculate the organ doses in Tables A-2, 3, 4, and 5.

Organ dose (rem) = Entrance kerma (cGy) x Organ DCF (mGy/Gy) x 1.0 E-3 (rem-Gy/cGy-mGy)

where the entrance kerma is in centigray (cGy) and the organ DCF is in milligray (mGy)/gray (Gy). To 

obtain the organ dose in rem, the equation must be multiplied by 1.0 E-03 (rem-Gy/cGy-mGy). 

The appropriate entrance kerma is selected from Table 3-4 and the DCFs are taken from the 

International Commission on Radiological Protection (ICRP) Report No. 34 (ICRP 1982) and guidance 

in ORAUT (2005)). 

Specific organ doses for the PA chest X-rays and PFG chest films calculated on the basis of the dose 

conversion factors found in ICRP (1982) and guidance in ORAUT (2005) are given in Tables A-2, 3, 4, 

and 5. Doses for organs not listed in ICRP (1982) but specified in the Interactive RadioEpidemiological Program (IREP) code were determined by analogy with anatomical location as 

indicated in Table 3-5 below. This table applies only to 14” x 17” chest X-rays; it is not used for other 

types of X-rays or for chest PFG films.
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 12 of 23

It is assumed that the X-ray beam was poorly collimated for X-rays taken before about 1965 (ORAUT 

2003). Therefore, organs not normally in the primary beam for a PA chest were included in the 

primary beam by using ICRP (1982) organ dose conversion factors (DCFs) for procedures where 

those organs would normally be included in the primary beam or dose data from the literature was 

used. For example, assuming no collimation, the ovaries would be in the primary beam, and DCFs for 

the abdomen were used. Abdomen DCFs were used for ovaries, testes, uterus, and their analogues. 

The cervical spine DCF was used for the thyroid and its analogue (ORAUT 2005). 

Table 3-5. Analogues for IREP organs not included in 

ICRP (1982) for 14” x 17” chest X-rays only (ORAUT 

2005). 

Anatomical

location

ICRP 1982 

reference organ

IREP organ

analogues

Thorax Lung Thymus

Esophagus

Stomach

Liver/gall bladder

Bone surface

Remainder organs

Abdomen Ovaries Urinary bladder

Colon/rectum

Head and neck Thyroid Eye/brain

ICRP (1982) provides tables of average absorbed dose in milligray (mGy) in selected organs for 

selected X-ray projections at 1 gray (Gy) entrance kerma (i.e., air kerma without backscatter), for 

selected projections (including PA chest), and for selected beam qualities, (i.e., various HVLs). These 

tables provide the basic DCFs for converting entrance air kerma to organ dose. 

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, provides an indication of the confidence of the dose estimates. Error 

implies knowledge of what the correct or actual value is, which is, of course, not known. Hence a 

more appropriate term is uncertainty, which is expressed in terms of a confidence level, e.g. 99%. 

This means that the correct or true value, although not actually known, has a 99% probability of falling 

within the range cited. The uncertainty includes both the precision, i.e., how reproducible the 

measurement is, and the accuracy, i.e., how close the measurement or estimate of dose comes to the 

actual or correct value (ORAUT 2005). 

In theory a large number of variables can introduce uncertainties or affect the X-ray machine output 

intensity and dose to the worker. In practice only four variables can be reasonably considered to have 

an impact on dose uncertainty. These are variations in (1) applied kVp, (2) beam current, 

(3) exposure time, and (4) distance from the worker to the source of the X-rays (source-to-skin 

distance [SSD]) (ORAUT 2003). Other variables, such as the use of screens and grids, reciprocity 

failure, film speed and development, would not affect the beam output intensity (ORAUT 2005). 

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

and unvarying. Although this is not always true in practice, the output is essentially constant unless 

focal spot loading occurs when the power rating of the machine is exceeded. This is unlikely because 

it would be difficult to achieve in practice and would damage the X-ray tube. However, even with the 

use of constant voltage transformers to control line voltages, slight variations may occur in line voltage 
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 13 of 23

input or other internal voltages, which could alter the kVp of the output beam. For a given kVp setting, 

the variation in kVp falls within ±5% of the machine setting (Seibert et al. 1991). The beam intensity is 

approximately proportional to the 1.7 power of the kilovoltage (ORAUT 2005). This translates to an 

uncertainty of approximately ±8.6% for the output beam intensity in the 76-84 and 105-116 kVp 

ranges. For conservatism, this is rounded up to ±9% (ORAUT 2005). 

Similarly, slight variations in tube current are normal. As a tube ages or heats up from usage, the

tube current may change and typically it will drop. Hence, with all other factors remaining constant,

the beam output 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 (ORAUT 2005). Large decreases in beam output will be readily detected (ORAUT 2005). 

This will result in performing maintenance on the machine to restore the output, or, as a temporary 

stopgap measure, increasing the current or kVp to provide the necessary beam output for proper 

radiography. For a given kVp setting, the beam output is a function of the tube current. A 

milliammeter on the machine measures the average tube current. This measurement is subject to 

uncertainties (ORAUT 2005). In addition, there may be minor changes in output as the tube heats up 

from normal usage, but these variations are typically small. Hence the uncertainty in beam output 

attributable to current variation has been estimated at ±5% (ORAUT 2005). 

Another parameter that has potential to affect the dose, perhaps significantly, relates to the exposure

time. This can be readily 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 correspondingly 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, although timer accuracy 

improved significantly with the introduction of electronic timers. However, once again for 

conservatism, the uncertainty in the beam output attributable to timers will be assumed to have an 

upper limit of ±25% (ORAUT 2005). 

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 (ESE). For a given individual, the source-to-skin 

distance (SSD) will be determined largely by the thickness of the worker and the accuracy in 

positioning the worker. For a typical worker, this variation in SSD is estimated at no more than a few 

centimeters, with an upper limit of perhaps 7.5 cm. Using the inverse square law, this indicates an 

uncertainty of ±10 % from this source (ORAUT 2005). 

Two approaches can be used to determine the combined uncertainty from the above four potential 

sources of uncertainty. The first, and most conservative in that it gives the greatest range, would be 

to assume that the uncertainties are additive. This 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

(ORAUT 2005). The RMS value is simply the square root of the sum of the squares, and computes 

as ±28.7%. Thus, for any individual ESE or derived organ dose, an uncertainty of ±30 % at the 99% 

confidence level may be assumed. For further conservatism, it may be appropriate to assume that 

errors are all positive, and only the + 30% should be used (ORAUT 2005). 
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 14 of 23

3.6 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.

[1] Murray, William E. Oak Ridge Associated Universities. Health Physicist 4. March 7, 2007.

The basis for specifying more frequent X-rays for these workers is taken from a document 

entitled “Occupational Accidents and Diseases” (Y-12 Plant, no date, SRDB Ref. ID: 4685, p. 

9). Although this document is not dated, Sections 5 through 9 (pp. 11-17) are taken from a 

memorandum written by a physician in the United States Engineer Office in Oak Ridge, 

Tennessee, about the Y-12 X-Ray Department on February 23, 1945 (SRDB Ref ID 4691). It 

is favorable to the claimant to assume that workers in these occupational groups received 

employer-required medical X-ray examinations more frequently than other workers. This 

assumption applies to the time period from March 1943 through December 1947. 

[2] Murray, William E. Oak Ridge Associated Universities. Health Physicist 4. March 9, 2007.

Regarding Table 3.2, there are multiple references documenting the use of photofluorographic 

machines and photofluorographic (PFG) film [Ref ID 8626, 12326 (p. 13), Ref ID 4691 (p. 4)]. 

There is a copy of a telegram from the Medical Director at Y-12 to GE X-Ray Corp. in 

Nashville requesting the installation of the PFG unit. William (Jack) Beck confirmed that 

photofluorographic X-rays were taken only during the 1943-1947 period. Ref ID 8609 states 

there were three medical facilities that served Y-12. Two were on the Y-12 site. The other is 

the Oak Ridge Hospital, which was run by the U.S. Army Corps of Engineers (USACE). Preemployment PFG X-rays were taken at the Y-12 Medical Facility and the Oak Ridge Hospital. 

Regarding the discrepancy in the dates for the Type III X-ray equipment, it is stated in Ref ID 

8634 that Ms. Patsy Shelton found documentation indicating that the time periods in the 

information provided by Steve Wiley were incorrect. Ms. Shelton said the X-ray machine was 

installed in 1969, not in the early 1960s.

[3] Murray, William E. Oak Ridge Associated Universities. Health Physicist 4. March 7, 2007.

The basis for specifying more frequent X-rays for these workers is taken from a document 

entitled “Occupational Accidents and Diseases” (Y-12 Plant, no date, SRDB Ref. ID: 4685, p. 

9). Although this document is not dated, Sections 5 through 9 (pp. 11-17) are taken from a 

memorandum written by physician in the United States Engineer Office in Oak Ridge, 

Tennessee, about the Y-12 X-Ray Department on February 23, 1945 (SRDB Ref ID 4691). It 

is favorable to the claimant to assume that workers in these occupational groups received

employer-required medical X-ray examinations more frequently than other workers. This 

assumption applies to the time period from March 1943 through December 1947. 
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 15 of 23

REFERENCES

Beck W.L., 2003, “Beck’s Notes on Y-12 Plant Medical X-rays,” Personal Correspondence (e-mail), 

August 13, 2003. [SRDB Ref ID: 8634] 

Cardarelli, J.J., Spitz, H., Rice, C., Buncher, R., Elson, H., and Succop, P., 2002, “Significance of 

Radiation Exposure from Work-Related Chest X-Rays for Epidemiological Studies of Radiation 

Workers,” Amer. J. Ind. Med.,42:490-501. [SRDB Ref ID: 8159]

42 C.F.R. Parts 81 and 82, 2002, Guidelines for Determining the Probability of Causation and 

Methods for Radiation Dose Reconstruction Under the Employees Occupational Illness

Compensation Program Act of 2000; Final Rules, Department of Health and Human Services,

Federal Register, Vol. 67, No. 85, May 2, pp. 22296;22314. 

Graham, W.H., 1946, “X-Ray Film,” Letter to Dr. F.T. Rogers at Oak Ridge Hospital, June 26, 1946. 

[SRDB Ref ID: 12326, p. 25] 

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

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

Leggo, C., 1945, “Telegram to Mr. E.C. Evans,” October 12, 1945. [SRDB Ref ID: 12326, pp. 20-21]

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

Beam and Gamma-Ray Protection up to 50 MeV (Equipment Design, Performance and Use), 

NCRP Report No. 102, Bethesda, Maryland.

Neely, W.E., 1943, Letter to Major W.E. Kelly at U.S. Engineer Office, May 13, 1943. [SRDB Ref ID: 

8609]

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

Related Diagnostic X-Ray Procedures, ORAUT-OTIB-0006, Rev 03 PC-1, December 21. 

ORAUT (Oak Ridge Associated Universities Team), 2006, Occupational X-Ray Dose Reconstruction 

for DOE Sites, ORAUT-PROC-0061, Rev 01, Oak Ridge, Tennessee, July 21.

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

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

American Institute of Physics, New York.

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

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

Wiley, S.W., 2002, Letter to Mr. James Newton, April 10, 2002. [SRDB Ref ID: 8394] 

Wolf, B.S., 1945, “X-ray Department at Y-12, as of 23 February 1945,” Memorandum for the files, 

Army Service Forces, United States Engineer Office, Manhattan District, Oak Ridge, 

Tennessee, February 23, 1945. [SRDB Ref ID: 4691]

Y-12 Plant, various dates, X-ray Information at Tennessee Eastman Corporation (Y-12). [SRDB Ref 

ID: 12326] 

Y-12 Plant, no date, Occupational Accidents and Diseases. [SRDB Ref ID: 4685]
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 16 of 23

GLOSSARY

Calutron

An electromagnetic apparatus for separating isotopes according to their masses. 

Entrance kerma

See kerma. 

Entrance skin exposure (ESE)

The exposure at the point where the X-ray beam enters the skin.

Film speed

A measure of the sensitivity of the film to X-rays or light.

Filtration

Material in the useful beam which usually absorbs preferentially the less penetrating 

radiation. 

Focal spot

The apparent size of the radiation source region in a source assembly when viewed 

from the central axis of the useful radiation beam. 

Gray (Gy)

The special name for the SI unit of absorbed dose, kerma, and specific energy 

imparted equal to one (1) joule per kilogram (J/kg). (1 Gy = 1 J/kg = 100 rad) 

Grid

A series of lead strips used to improve the quality of radiographic images by removing 

scattered X-rays. 

Half value layer (HVL)

Thickness of a specified substance which, when introduced into the path of a given 

beam of radiation, reduces the kerma rate by one-half. (Usually specified in mm Al.)

Interactive RadioEpidemiological Program (IREP)

A computer software program that uses information on the dose-response relationship,

and specific factors such as a claimant’s radiation exposure, gender, age at diagnosis, 

and age at exposure to calculate the probability of causation for a given pattern and 

level of radiation exposure.

International Commission on Radiological Protection (ICRP)

An independent Registered Charity, established to advance for the public benefit the 

science of radiological protection, in particular by providing recommendations and 

guidance on all aspects of protection against ionising radiation.

Inverse square law

The relationship between the exposure rate from a point source of radiation and the 

distance from the source.
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 17 of 23

Kerma

The sum of the initial kinetic energies of all the charged ionizing particles liberated by 

uncharged ionizing particles per unit mass of a specified material. 

Kiloelectronvolt (keV)

The energy equal to that acquired by a particle with one electron charge in passing 

through a potential difference of 1000 volts. 

Milliammeter

An instrument for measuring electric current in milliamperes. 

National Council on Radiation Protection and Measurements (NCRP)

A nongovernmental, public service organization that formulates and disseminates 

information, guidance and recommendations on radiation protection and 

measurements. 

Organ dose

The dose to a given organ from an X-ray procedure.

Photofluorography

An obsolete radiographic technique in which the image produced on a fluorescent 

screen by X-rays was photographed. 

Photon

A quantum of electromagnetic radiation. 

Posterior/anterior (P/A)

An X-ray in which the X-ray beam passes from posterior to the anterior side of the 

patient.

Pre-placement X-ray

An X-ray, usually a chest X-ray, taken before a worker is hired or assigned to a 

specific job.

Probability of causation (POC)

The probability or likelihood that a cancer was caused by radiation exposure incurred 

by a covered employee in the performance of duty. 

Pulmonary

Relating to, functioning like, or associated with the lungs. 

Root-mean-square

The square root of the arithmetic mean of the squares of a set of numbers. 

Screens

A fluorescent material used in diagnostic radiology that absorbs the X-rays and 

converts it into light that exposes the X-ray film.

Source-to-image distance (SID)

The distance measured along the central ray from the center of the front of the surface 

of the source (focal spot) to the surface of the image detector. 
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 18 of 23

Source-to-skin distance (SSD)

The distance measured along the central ray from the center of the front of the surface 

of the source (focal spot) to the surface of the irradiated object or the patient. 

Technique factors

The variables, i.e., the peak voltage (kVp), current (mA), and time (s), that are used for 

taking an X-ray.

Termination X-ray

An X-ray, usually a chest X-ray that is taken when the employee is separated from the 

company.

Tube current

The current flowing from the cathode to the anode in an X-ray tube.

Variable

A quantity that may assume any one of a set of values.

X-ray

Electromagnetic radiation of the same nature as visible radiation but having an 

extremely short wavelength of less than 10-8 m; an image obtained by use of X-rays.

X-ray tube

An evacuated electronic tube in which X-rays are generated when electrons are 

accelerated by an applied voltage and strike an anode or target. 
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 19 of 23

ATTACHMENT A 

OCCUPATIONAL MEDICAL DOSE

Page 1 of 5 

TABLE OF CONTENTS

SECTION TITLE

A.1 Y-12 Medical X-Ray Program............................................................................................

PAGE

20

A.2 Dose Reconstructor Instructions....................................................................................... 20

 A.2.1 Assignment of Organ Doses from X-ray Procedures: Maximizing 

 Approach for Dose Reconstructions ..................................................................... 20

 A.2.2 Assignment of Organ Doses from X-ray Procedures: Best 

 Estimate Approach for Dose Reconstructions........................................................ 20

LIST OF TABLES

TABLE TITLE PAGE

A-1 Frequency of occupational chest x-rays at Y-12..................................................................... 20

A-2 Organ doses (rem) for a beam quality (HVL) of 2.5 mm Al and 80 kVp 

(1943-1947) ...........................................................................................................................22

A-3 Organ doses (rem) for a beam quality (HVL) of 2.5 mm Al and 80 kVp 

(1948-1968) assuming no collimation..................................................................................... 22

A-4 Organ doses (rem)a for a beam quality (HVL) of 2.5 mm Al and 80 kVp 

(1969-January 1982).............................................................................................................. 23

A-5 Organ doses (rem)a for a beam quality (HVL) of 3.5 mm Al and 110 kVp 

(January 1982-present).......................................................................................................... 23
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 20 of 23

A.1 Y-12 MEDICAL X-RAY PROGRAM

Y-12 conducted pre-placement and annual physical examinations as part of its occupational health 

program. These examinations typically included a chest X-ray. In general, the frequency of the 

examinations over the years and by age of the worker is shown in Table A-1 (Wiley 2002). For some 

workers, and occupations, chest X-rays could be more frequent. For example, food handlers and 

cafeteria workers were examined every 6-12 months; alpha (calutron) workers were examined twice 

per year; and liquid phase workers exposed to uranium, phosgene or carbon tetrachloride underwent 

three examinations per year [3]. 

Table A-1. Frequency of occupational posterior/anterior chest X-rays at Y-12 (Wiley 2002).a

 

Period Frequency Comment

1943 –

Present

Pre-placement All employees

At termination All employees

1943 –

July 18,1988

Annually All employees

July 18, 1988 –

Present

Time of entry into 

hazardous job

Asbestos and beryllium workers and other jobs with potential 

pulmonary pathogens

July 18, 1988 –

March 1998

Annually Active and previous asbestos and beryllium workers

July 18, 1988 –

June 30, 1993

Every 10 years Employees under 30 years old

Every 5 years Employees aged 30-45 years old

Every 3 years Employees over 45 years old

March 1998 –

Present

Annually Active asbestos workers

Every 3 years Previous asbestos workers; active and previous beryllium workers

a. Workers in certain occupations may have received chest X-rays more frequently. This information may be in the 

energy employee’s file provided by DOE.

A.2 DOSE RECONSTRUCTOR INSTRUCTIONS

The information given below summarizes instructions given to the dose reconstructors in determining 

organ doses from occupational medical X-ray procedures. For the purpose of evaluating POC, X-ray 

doses are always considered acute, and are considered to be photons with energies in the range from 

30 to 250 kiloelectronvolts (keV).

A.2.1 Assignment of Organ Doses from X-ray Procedures: Maximizing Approach for Dose 

The X-ray doses presented above are treated as a point estimate (constant) for the purpose of 

calculating POC (ORAUT 2006). 

Reconstructions

A.2.2 

 

Assignment of Organ Doses from X-ray Procedures: Best Estimate Approach for

For the dose calculation, a normal distribution is applied with a standard deviation of 30%. The value 

of the standard deviation is equal to the mean value times 30%. Thus, the dose reconstructor should 

multiply the organ doses listed in Tables A-2, 3, 4, and 5 by 1.3. The dose reconstructor may use a 

Dose Reconstructions

ATTACHMENT A

OCCUPATIONAL MEDICAL DOSE

Page 2 of 5 
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 21 of 23

frequency other than annual if the actual frequency is known and apply the guidance in A.2.1 above 

(ORAUT 2006). 

ATTACHMENT A

OCCUPATIONAL MEDICAL DOSE

Page 3 of 5 
Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 22 of 23

1 

Table A-2. Organ doses (rem)a for a beam 

quality (HVL) of 2.5 mm Al and 80 kVp (Type I 

machine; 1943-1947). 

Organ

Organ dose from 

photofluorographic 

chest X-ray (rem)

Entrance air kerma 3.00E+00b

Thyroid c 5.22E-01

Eye/brain 9.60E-02

Ovaries e 2.5 E-02 

Liver/gall bladder 1.35E+00

Urinary bladder e 2.5 E-02 

Colon/rectum e 2.5 E-02 

Testes e 5.0 E-03 

Lungs (male) 1.26E+00

Lungs (female) 1.35E+00

Thymus 1.35E+00

Esophagus 1.35E+00

Stomach 1.35E+00

Bone surface 1.35E+00

Remainder 1.35E+00

Breast 1.47E-01

Uterus e 2.5 E-02 

Bone marrow (male) 2.76E-01

Bone marrow (female) 2.58E-01

Skin d 4.05E+00

a. For organs listed in ICRP 34 (1982) and proximal 

organs for input to IREP.

b. ORAUT (2005). 

c. The DCF for the AP cervical spine was used, 

corrected by a 20% depth dose factor (NCRP (1989), 

Table B-8). 

d. Skin dose is entrance skin kerma, multiplied by a 

backscatter factor of 1.35 from NCRP 102, Table B8.

e. Modified from Webster.

Table A-3. Organ doses (rem) a for a beam 

quality (HVL) of 2.5 mm Al and 80 kVp (Type II 

machine; 1948-1968) assuming no collimation. 

Organ

Organ dose from 

posterior/anterior 

chest X-ray (rem)

Entrance air kerma 2.00E-01b

Thyroid c 3.48E-02

Eye/brain 6.40E-03

Ovaries e 2.50E-02

Liver/gall bladder 9.02E-02

Urinary bladder e 2.50E-02

Colon/rectum e 2.50E-02

Testes e 5.00E-03

Lungs (male) 8.38E-02

Lungs (female) 9.02E-02

Thymus 9.02E-02

Esophagus 9.02E-02

Stomach 9.02E-02

Bone surface 9.02E-02

Remainder 9.02E-02

Breast 9.80E-03

Uterus e 2.50E-02

Bone marrow (male) 1.84E-02

Bone marrow (female) 1.72E-02

Skin d 2.70E-01

a. For organs listed in ICRP (1982) and proximal 

organs for input to IREP.

b. ORAUT (2005). 

c. The DCF for the AP cervical spine was used, 

corrected by a 20% depth dose factor (NCRP (1989), 

Table B-8). 

d. Skin dose is entrance skin kerma, multiplied by a 

backscatter factor of 1.35 from NCRP (1989), Table 

B-8.

e. Modified from Webster.

ATTACHMENT A

OCCUPATIONAL MEDICAL DOSE

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Document No. ORAUT-TKBS-0014-3 Revision No. 01 Effective Date: 06/18/2007 Page 23 of 23

Table A-4. Organ doses (rem)a for a beam 

quality (HVL) of 2.5 mm Al and 80 kVp (1969-

January 1982). 

Organ

Organ dose from 

Posterior/anterior 

chest X-ray (rem)

Entrance air kerma 1.00E-01b

Thyroid 3.20E-03

Eye/brain 3.20E-03

Ovaries 1.00E-04

Liver/gall bladder 4.51E-02

Urinary bladder 1.00E-04

Colon/rectum 1.00E-04

Testes 1.00E-06

Lungs (male) 4.19E-02

Lungs (female) 4.51E-02

Thymus 4.51E-02

Esophagus 4.51E-02

Stomach 4.51E-02

Bone surface 4.51E-02

Remainder 4.51E-02

Breast 4.90E-03

Uterus 1.30E-04

Bone marrow (male) 9.20E-03

Bone marrow (female) 8.60E-03

Skin c 1.35E-01

a. For organs listed in ICRP (1982) and proximal 

organs for input to IREP.

b. ORAUT (2005). 

c. Skin dose is entrance skin kerma, multiplied by a 

backscatter factor of 1.35 from NCRP (1989), Table 

B-8.

Table A-5. Organ doses (rem)a for a beam 

quality (HVL) of 3.5 mm Al and 110 kVp 

(January 1982-present). 

Organ

Organ dose from 

posterior/anterior 

chest X-ray (rem)

Entrance air kerma 5.00E-02b

Thyroid 3.10E-03

Eye/brain 3.10E-03

Ovaries 1.60E-04

Liver/gall bladder 3.05E-02

Urinary bladder 1.60E-04

Colon/rectum 1.60E-04

Testes 5.00E-07

Lungs (male) 2.83E-02

Lungs (female) 3.05E-02

Thymus 3.05E-02

Esophagus 3.05E-02

Stomach 3.05E-02

Bone surface 3.05E-02

Remainder 3.05E-02

Breast 4.55E-03

Uterus 1.50E-04

Bone marrow (male) 7.30E-03

Bone marrow (female) 7.05E-03

Skin c 7.00E-02

a. For organs listed in ICRP (1982) and proximal 

organs for input to IREP.

b. ORAUT (2005). 

c. Skin dose is entrance skin kerma, multiplied by a 

backscatter factor of 1.4 from NCRP (1989), Table B8. 

ATTACHMENT A

OCCUPATIONAL MEDICAL DOSE

Page 5 of 5