Age Modifies the Effect of 2-MeV Fast Neutrons on Rat Mammary Carcinogenesis.
Radiat Res
; 188(4): 419-425, 2017 10.
Article
en En
| MEDLINE
| ID: mdl-28809605
The relative biological effectiveness (RBE) of neutrons depends on their physical nature (e.g., energy) and the biological context (e.g., end points, materials). From the perspective of radiological protection, age is an important biological context that influences radiation-related cancer risk, but very few studies have addressed its potential impact on neutron effects. We therefore investigated the influence of age on the effect of accelerator-generated fast neutrons (mean energy, â¼2 MeV) in an animal model of breast carcinogenesis. Female Sprague-Dawley rats at 1, 3 and 7 weeks of age were irradiated with fast neutrons at absorbed doses of 0.0485-0.97 Gy. All animals were kept under specific pathogen-free conditions and screened weekly for mammary tumors by palpation until they were 90 weeks old. Tumors were diagnosed based on histology. Mathematical modeling was used to analyze mammary cancer incidence, collectively using data from this study and a previously reported experiment on 137Cs gamma rays. The results indicate that neutron irradiation elevated the risk of palpable mammary carcinoma with a linear dose response, the slope of which depended on age at time of irradiation. The RBE of neutron radiation was 7.5 ± 3.4, 9.3 ± 3.5 and 26.1 ± 8.9 (mean ± SE) for animals exposed at 1, 3 and 7 weeks of age, respectively. Our results indicate that age of the animal is an important factor influencing the effect of fast neutrons on breast cancer risk.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Envejecimiento
/
Neutrones Rápidos
/
Neoplasias Mamarias Experimentales
Tipo de estudio:
Etiology_studies
/
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Radiat Res
Año:
2017
Tipo del documento:
Article
País de afiliación:
Japón
Pais de publicación:
Estados Unidos