Upper limit of magnetic effect on α/ß ratio.
Phys Med Biol
; 60(17): N325-34, 2015 Sep 07.
Article
en En
| MEDLINE
| ID: mdl-26301729
ABSTRACT
Magnetic resonance imaging (MRI) is being integrated into radiotherapy delivery for MRI-guided radiotherapy. The purpose of this work is to investigate theoretically the upper limit of any potential magnetic effect on the α/ß ratio, an important radiobiological parameter in radiation therapy. Based on the theory of dual radiation action, the α/ß ratio can be expressed by an integral of the product of two microdosimetry quantities (x) and t(x), where (x) is the probability that two energy transfers, a distance x apart, results in a lesion, and t(x) is the proximity function, which is the energy-weighted pointpair distribution of distances between energy transfer points in a track. The quantity t(x) depends on the applied magnetic field. An analytical approach has been used to derive a formula that can be used to calculate the α/ß ratio in an extremely strong magnetic field, which gives the upper limit of the potential changes of the α/ß ratio due to the presence of a magnetic field. For V79 Chinese hamster cells the upper limit of the increase of the α/ß ratio with a magnetic field has been found to be 2.90 times for Pd-103, 2.97 times for I-125 and 2.3 times for Co-60 sources.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Partículas beta
/
Imagen por Resonancia Magnética
/
Partículas alfa
/
Campos Magnéticos
Límite:
Animals
Idioma:
En
Revista:
Phys Med Biol
Año:
2015
Tipo del documento:
Article
País de afiliación:
Canadá