Relative Biological Effectiveness of Energetic Heavy Ions for Intestinal Tumorigenesis Shows Male Preponderance and Radiation Type and Energy Dependence in APC{sup 1638N/+} Mice

Journal Article · Sun May 01 04:00:00 EDT 2016 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2015.10.057· OSTI ID:22648623

Suman, Shubhankar; Kumar, Santosh; Moon, Bo-Hyun; Strawn, Steve J.; Thakor, Hemang; Fan, Ziling ^[1]; Shay, Jerry W. ^[2]; Fornace, Albert J. ^[1]; Datta, Kamal ^[1]

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1. Department of Biochemistry and Molecular & Cellular Biology and Lombardi Comprehensive Cancer Center, Georgetown University, Washington, District of Columbia (United States)
2. Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas (United States)

Purpose: There are uncertainties associated with the prediction of colorectal cancer (CRC) risk from highly energetic heavy ion (HZE) radiation. We undertook a comprehensive assessment of intestinal and colonic tumorigenesis induced after exposure to high linear energy transfer (high-LET) HZE radiation spanning a range of doses and LET in a CRC mouse model and compared the results with the effects of low-LET γ radiation. Methods and Materials: Male and female APC{sup 1638N/+} mice (n=20 mice per group) were whole-body exposed to sham-radiation, γ rays, {sup 12}C, {sup 28}Si, or {sup 56}Fe radiation. For the >1 Gy HZE dose, we used γ-ray equitoxic doses calculated using relative biological effectiveness (RBE) determined previously. The mice were euthanized 150 days after irradiation, and intestinal and colon tumor frequency was scored. Results: The highest number of tumors was observed after {sup 28}Si, followed by {sup 56}Fe and {sup 12}C radiation, and tumorigenesis showed a male preponderance, especially after {sup 28}Si. Analysis showed greater tumorigenesis per unit of radiation (per cGy) at lower doses, suggesting either radiation-induced elimination of target cells or tumorigenesis reaching a saturation point at higher doses. Calculation of RBE for intestinal and colon tumorigenesis showed the highest value with {sup 28}Si, and lower doses showed greater RBE relative to higher doses. Conclusions: We have demonstrated that the RBE of heavy ion radiation-induced intestinal and colon tumorigenesis is related to ion energy, LET, gender, and peak RBE is observed at an LET of 69 keV/μm. Our study has implications for understanding risk to astronauts undertaking long duration space missions.

• OSTI ID: 22648623
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 1 Vol. 95; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CARBON 12
ENERGY DEPENDENCE
GAMMA RADIATION
GY RANGE 01-10
HEAVY IONS
IRON 56
KEV RANGE 10-100
LARGE INTESTINE
LET
MICE
NEOPLASMS
RADIATION HAZARDS
RADIOTHERAPY
RBE
SILICON 28