Page 422 - 2014 Printable Abstract Book
P. 422
(PS7-75) Organ dose conversion coefficients for children exposed to external photon radiation beams.
Lienard Chang and Choonsik Lee, PhD; National Cancer Institute, Rockville, MD
In the event of a radiological accident or attack, it is important to estimate the organ doses that
those who are exposed receive. Under normal circumstances, it is difficult to measure organ dose directly
in the field and therefore an organ dose conversion coefficient (ODCC) is needed to convert measurable
values such as air kerma and fluence to organ dose. Previous works on these coefficients have been
conducted mainly for adults (ICRP Publications 74 and 116) with a focus on radiation protection workers.
There is a large gap in the literature for pediatric values. In this study, with use of Monte Carlo N-Particle
eXtended (MCNPX) code, we calculated a comprehensive list of organ dose conversion coefficients
(mGy/mGy) to convert air-kerma to organ dose for ICRP-adopted National Cancer Institute/University of
Florida pediatric reference phantoms. These phantoms are most realistic and flexible, created using
voxels, as opposed to the earliest generation of stylized phantoms. Consistent with ICRP 116 for adult
data, our calculations consisted of ten (10) phantoms (newborn, 1-year, 5-year, 10-year, 15-year old male
and female), 28 organs over 33 energies between 0.01 and 20 MeV in six (6) irradiation geometries
relevant to a child who might be exposed to a radiological accident or attack: anterior-posterior (AP),
posterior-anterior (PA), right-lateral (RLAT), left-lateral (LLAT), rotational (ROT), and isotropic (ISO).
10,000,000 particles histories were incorporated and ran on an 8-core server over the course of one
month for the AP, PA, and lateral directions while 100,000,000 particles histories were run for the ROT
and ISO directions to achieve acceptable statistical errors in organ doses. Additionally, organ dose
conversion coefficients to the red bone marrow over 36 skeletal sites were calculated, as well as overall
effective dose. Along with tabulation of these values, age-dependent as well as irradiation geometry-
dependent graphs were created. Future works includes expanding particle types, such as neutrons.
(PS7-76) A survey of radioisotope procedures and radiation safety practices from 1945 to 2009 in U.S.
2
1
2
2
radiologic technologists. Miriam E. Van Dyke ; Vladimir Drozdovitch ; Michele Doody ; Steve Simon ;
2
2
1
Martha Linet ; and Cari Kitahara , Emory University, Atlanta, GA and National Cancer Institute, Rockville,
2
MD
Background: Ionizing radiation (IR) is a known carcinogen and is linked to increased risks of various
cancers, including leukemia, thyroid, skin, and breast. However, there is limited information on the long-
term health effects of chronic low-dose IR exposures of particular concern to certain occupational groups.
The field of nuclear medicine, for example, has rapidly expanded over the past few decades, but changes
in the radioisotope procedures performed, radionuclides used, and radiation safety practices employed
have not been well-characterized. Methods: The United States Radiologic Technologists (USRT) Study is a
nationwide, prospective cohort study with detailed health and occupational information on more than
110,000 radiologic technologists (RTs). In a fourth cohort questionnaire mailed to 94,000 known living
technologists during 2013-2014, 9,398 RTs who reported working with diagnostic and/or therapeutic
radioisotope procedures at least once a month for a year or more were asked to complete a follow-up
work history questionnaire detailing the frequency and types of radioisotope procedures they performed
during 1945-2009, and the radiation safety and protection practices they employed. A sample was also
asked to provide information on the specific radionuclides they used when performing these procedures
over time. Demographics and cancer and other disease risk factor data were gathered in previously-
Lienard Chang and Choonsik Lee, PhD; National Cancer Institute, Rockville, MD
In the event of a radiological accident or attack, it is important to estimate the organ doses that
those who are exposed receive. Under normal circumstances, it is difficult to measure organ dose directly
in the field and therefore an organ dose conversion coefficient (ODCC) is needed to convert measurable
values such as air kerma and fluence to organ dose. Previous works on these coefficients have been
conducted mainly for adults (ICRP Publications 74 and 116) with a focus on radiation protection workers.
There is a large gap in the literature for pediatric values. In this study, with use of Monte Carlo N-Particle
eXtended (MCNPX) code, we calculated a comprehensive list of organ dose conversion coefficients
(mGy/mGy) to convert air-kerma to organ dose for ICRP-adopted National Cancer Institute/University of
Florida pediatric reference phantoms. These phantoms are most realistic and flexible, created using
voxels, as opposed to the earliest generation of stylized phantoms. Consistent with ICRP 116 for adult
data, our calculations consisted of ten (10) phantoms (newborn, 1-year, 5-year, 10-year, 15-year old male
and female), 28 organs over 33 energies between 0.01 and 20 MeV in six (6) irradiation geometries
relevant to a child who might be exposed to a radiological accident or attack: anterior-posterior (AP),
posterior-anterior (PA), right-lateral (RLAT), left-lateral (LLAT), rotational (ROT), and isotropic (ISO).
10,000,000 particles histories were incorporated and ran on an 8-core server over the course of one
month for the AP, PA, and lateral directions while 100,000,000 particles histories were run for the ROT
and ISO directions to achieve acceptable statistical errors in organ doses. Additionally, organ dose
conversion coefficients to the red bone marrow over 36 skeletal sites were calculated, as well as overall
effective dose. Along with tabulation of these values, age-dependent as well as irradiation geometry-
dependent graphs were created. Future works includes expanding particle types, such as neutrons.
(PS7-76) A survey of radioisotope procedures and radiation safety practices from 1945 to 2009 in U.S.
2
1
2
2
radiologic technologists. Miriam E. Van Dyke ; Vladimir Drozdovitch ; Michele Doody ; Steve Simon ;
2
2
1
Martha Linet ; and Cari Kitahara , Emory University, Atlanta, GA and National Cancer Institute, Rockville,
2
MD
Background: Ionizing radiation (IR) is a known carcinogen and is linked to increased risks of various
cancers, including leukemia, thyroid, skin, and breast. However, there is limited information on the long-
term health effects of chronic low-dose IR exposures of particular concern to certain occupational groups.
The field of nuclear medicine, for example, has rapidly expanded over the past few decades, but changes
in the radioisotope procedures performed, radionuclides used, and radiation safety practices employed
have not been well-characterized. Methods: The United States Radiologic Technologists (USRT) Study is a
nationwide, prospective cohort study with detailed health and occupational information on more than
110,000 radiologic technologists (RTs). In a fourth cohort questionnaire mailed to 94,000 known living
technologists during 2013-2014, 9,398 RTs who reported working with diagnostic and/or therapeutic
radioisotope procedures at least once a month for a year or more were asked to complete a follow-up
work history questionnaire detailing the frequency and types of radioisotope procedures they performed
during 1945-2009, and the radiation safety and protection practices they employed. A sample was also
asked to provide information on the specific radionuclides they used when performing these procedures
over time. Demographics and cancer and other disease risk factor data were gathered in previously-
