Page 193 - 2014 Printable Abstract Book
P. 193
compared to the data. For the nuclear interactions of primary GCR through Mars atmosphere and
Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation (QMSFRG) is used. For
describing the daily column depth of atmosphere, daily atmospheric pressure measurements at Gale
Crater by the MSL Rover Environmental Monitoring Station (REMS) are implemented into transport
calculations. Particle flux at RAD after traversing varying depths of atmosphere depends on the slant
angles, and the model accounts for shielding of the RAD “E” dosimetry detector by the rest of the
instrument. Detailed comparisons between model predictions and spectral data of various particle types
provide the validation of radiation transport models, and thus increase the accuracy of the predictions of
future radiation environments on Mars. These contributions lend support to the understanding of
radiation health risks to astronauts for the planning of various mission scenarios.
1
(PS3-07) Update of harderian gland tumorigenesis: low dose- and LET-response. Polly Y. Chang, PhD ;
1
2
1
2
Kathleen A. Bjornstad, BS ; James P. Bakke, BS ; Chris J. Rosen, BS ; Nicholas Du, BS ; David G. Fairchild,
DVM ; and Eleanor A. Blakely, PhD SRI International, Menlo Park, CA and Lawrence Berkeley National
1
1
2
2
Laboratory, Berkeley, CA
The goal of our project is to reduce the uncertainties in the Relative Biological Effect (RBE) and
Linear Energy Transfer (LET) relationship for particle radiation carcinogenesis risk for manned travel into
deep space by improving our understanding of the high-LET-dependent dose-response curve at low
particle doses (< 50 cGy), and by filling in the gaps in knowledge in the LET range between 25 and 193
keV/µm not covered by the historical Harderian Gland (HG) tumor prevalence data in the same strain of
animals that were used in studies of Fry et al. [1983], and Alpen et al. [1993].
Female CB6F1 (C57Bl/6J x BALB/CJ) mice were purpose bred and irradiated at 100 - 120 days old with low
(≤ 32 cGy) doses of 260 MeV/u Silicon ions (LET ~70 keV/µm), or with low (≤ 26 cGy) doses of 1 GeV/u
Titanium ions (LET ~100 keV/µm) at Brookhaven National Laboratory’s NASA Space Radiation Laboratory.
An adequate number of animals was included in each group to reach an 80% power. Animals were
monitored daily and weighed weekly until necropsy 16-months post treatment. Our results show that: (1)
the spontaneous HG tumor frequency in our study is consistent with the prior published frequency; (2)
the dose-dependent increase in HG tumor incidence after low doses of Si- or Ti-doses are nested, as
predicted, in between the incidences for 193 keV/µm (600 MeV/u Iron ions), and above the 25 keV/µm
(670 MeV/u Neon ions); (3) the histology of the HG tumors arising after either Si- or Ti-ion exposures
revealed primarily benign papillary adenomas; (4) Si-induced lung tumor incidence revealed a non-linear
dose- dependent increase, while preliminary Ti-ion results suggest that there are no statistically significant
increases in lung tumor incidence with increasing dose compared to the unirradiated controls; and (5)
histological evaluations of both Si- and Ti-ion induced lung tumors revealed benign bronchio-alveolar
adenomas were prevalent, with small percentages of bronchio-alveolar adenocarcinoma,
histiocytic/reticulum cell carcinoma and lymphoma in the higher Si doses. However, the percent of
animals with adenocarcinoma are higher after higher doses of Ti-ions.
These data indicate novel dose-, LET- and tissue-dependent differences in particle radiation
tumorigenesis. Acknowledgement: Supported by NASA Grant # NNJ11HA941.
191 | P a g e
Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation (QMSFRG) is used. For
describing the daily column depth of atmosphere, daily atmospheric pressure measurements at Gale
Crater by the MSL Rover Environmental Monitoring Station (REMS) are implemented into transport
calculations. Particle flux at RAD after traversing varying depths of atmosphere depends on the slant
angles, and the model accounts for shielding of the RAD “E” dosimetry detector by the rest of the
instrument. Detailed comparisons between model predictions and spectral data of various particle types
provide the validation of radiation transport models, and thus increase the accuracy of the predictions of
future radiation environments on Mars. These contributions lend support to the understanding of
radiation health risks to astronauts for the planning of various mission scenarios.
1
(PS3-07) Update of harderian gland tumorigenesis: low dose- and LET-response. Polly Y. Chang, PhD ;
1
2
1
2
Kathleen A. Bjornstad, BS ; James P. Bakke, BS ; Chris J. Rosen, BS ; Nicholas Du, BS ; David G. Fairchild,
DVM ; and Eleanor A. Blakely, PhD SRI International, Menlo Park, CA and Lawrence Berkeley National
1
1
2
2
Laboratory, Berkeley, CA
The goal of our project is to reduce the uncertainties in the Relative Biological Effect (RBE) and
Linear Energy Transfer (LET) relationship for particle radiation carcinogenesis risk for manned travel into
deep space by improving our understanding of the high-LET-dependent dose-response curve at low
particle doses (< 50 cGy), and by filling in the gaps in knowledge in the LET range between 25 and 193
keV/µm not covered by the historical Harderian Gland (HG) tumor prevalence data in the same strain of
animals that were used in studies of Fry et al. [1983], and Alpen et al. [1993].
Female CB6F1 (C57Bl/6J x BALB/CJ) mice were purpose bred and irradiated at 100 - 120 days old with low
(≤ 32 cGy) doses of 260 MeV/u Silicon ions (LET ~70 keV/µm), or with low (≤ 26 cGy) doses of 1 GeV/u
Titanium ions (LET ~100 keV/µm) at Brookhaven National Laboratory’s NASA Space Radiation Laboratory.
An adequate number of animals was included in each group to reach an 80% power. Animals were
monitored daily and weighed weekly until necropsy 16-months post treatment. Our results show that: (1)
the spontaneous HG tumor frequency in our study is consistent with the prior published frequency; (2)
the dose-dependent increase in HG tumor incidence after low doses of Si- or Ti-doses are nested, as
predicted, in between the incidences for 193 keV/µm (600 MeV/u Iron ions), and above the 25 keV/µm
(670 MeV/u Neon ions); (3) the histology of the HG tumors arising after either Si- or Ti-ion exposures
revealed primarily benign papillary adenomas; (4) Si-induced lung tumor incidence revealed a non-linear
dose- dependent increase, while preliminary Ti-ion results suggest that there are no statistically significant
increases in lung tumor incidence with increasing dose compared to the unirradiated controls; and (5)
histological evaluations of both Si- and Ti-ion induced lung tumors revealed benign bronchio-alveolar
adenomas were prevalent, with small percentages of bronchio-alveolar adenocarcinoma,
histiocytic/reticulum cell carcinoma and lymphoma in the higher Si doses. However, the percent of
animals with adenocarcinoma are higher after higher doses of Ti-ions.
These data indicate novel dose-, LET- and tissue-dependent differences in particle radiation
tumorigenesis. Acknowledgement: Supported by NASA Grant # NNJ11HA941.
191 | P a g e
