Relative Biological Effectiveness of Energetic Heavy Ions for Intestinal Tumorigenesis Shows Male Preponderance and Radiation Type and Energy Dependence in APC(1638N/+) Mice.
Int J Radiat Oncol Biol Phys
; 95(1): 131-138, 2016 May 01.
Article
em En
| MEDLINE
| ID: mdl-26725728
ABSTRACT
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(1638N/+) mice (n=20 mice per group) were whole-body exposed to sham-radiation, γ rays, (12)C, (28)Si, or (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 (28)Si, followed by (56)Fe and (12)C radiation, and tumorigenesis showed a male preponderance, especially after (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 (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.
Texto completo:
1
Coleções:
01-internacional
Temas:
Geral
/
Prevencao_e_fatores_de_risco
/
Agentes_cancerigenos
/
Tipos_de_cancer
/
Outros_tipos
Base de dados:
MEDLINE
Assunto principal:
Eficiência Biológica Relativa
/
Radioterapia com Íons Pesados
/
Raios gama
/
Neoplasias Intestinais
/
Neoplasias Induzidas por Radiação
Tipo de estudo:
Etiology_studies
/
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Int J Radiat Oncol Biol Phys
Ano de publicação:
2016
Tipo de documento:
Article