Asunto(s)
Oxígeno , Rabdomiosarcoma/radioterapia , Animales , Argón , Carbono , Línea Celular , Supervivencia Celular/efectos de la radiación , Relación Dosis-Respuesta en la Radiación , Técnicas In Vitro , Iones , Neón , Aceleradores de Partículas , Radioterapia de Alta Energía , Ratas , Efectividad Biológica RelativaAsunto(s)
Carbono , Neón , Rabdomiosarcoma/radioterapia , Animales , Supervivencia Celular , Relación Dosis-Respuesta en la Radiación , Trasplante de Neoplasias , Oxígeno , Radioterapia de Alta Energía , Ratas , Efectividad Biológica Relativa , Sarcoma Experimental/radioterapia , Trasplante HomólogoAsunto(s)
Radioterapia de Alta Energía , Rabdomiosarcoma/radioterapia , Animales , Relación Dosis-Respuesta en la Radiación , Femenino , Helio , Iones , Neón , Trasplante de Neoplasias , Neoplasias Experimentales/radioterapia , Aceleradores de Partículas , Ratas , Ratas Endogámicas , Efectividad Biológica Relativa , Factores de TiempoRESUMEN
Spinal cords of rats were exposed to either single doses of helium ions ranging from 500 to 3500 rads, or to fractionated doses of helium ions ranging from 1300 to 6530 rads using 10 equal fractions given over 22 days. Both plateau and spread-out Bragg peak regions of ionization were used. For single doses there was no difference betweenplateau or spread-out Bragg peak ionization regions for production of paralysis; thetolerance dose for production of paralysis was about 1900 rads. For the fractionation experiment, there was also no difference between plateau or spread-out Bragg peak ionization regions for production of paralysis; the tolerance dose was between 5220 and 6530rads. Comparison of dose levels producing about 10% partial paralysis indicates that about 500 rads of dose is recovered between fractions. In both single dose and fractionated experiments, latency between onset of paralysis was between 20 to 24 weeks.
Asunto(s)
Helio , Efectos de la Radiación , Médula Espinal/efectos de la radiación , Animales , Peso Corporal/efectos de la radiación , Relación Dosis-Respuesta en la Radiación , Masculino , Radioterapia de Alta Energía/instrumentación , Ratas , Tiempo de Reacción , Factores de TiempoRESUMEN
The response of a model brain tumor system in the rat to single doses of x irradiation has been studied. Solid tumors were exposed in situ, removed, dissociated into single cells, and grown in tissue culture. The fraciton of surviving clonogenic cells wasdetermined as a function of x-ray dose level for tumors irradiated in anesthetized, air-breathing rats, and for tumors irradiated in rats killed 5 minutes prior to irradiation bynitrogen gas asphyxiation. The parameters of the survival curve for tumors irradiatedin air-breathing rats were: DO= 295 rads; DQ= 350 rads; and n= 3.0. Similarly, thesurvival parameters for tumors irradiated in nitrogen gas asphyxiated rats were: DO=625 rads; DQ=675 rads; and n= 3.0. The survival curve of these tumor cells when assayed in in vitro tissue culture only has parameters of: DO= 225 rads; DQ= 350 rads; andn= 4.7. Data form the in vivo to in vivo tumor cell survival curves suggest that there is no significant hypoxic fraction in this brain tumor.