RBE of cyclotron fast neutrons for a rat brain tumor

Journal Article · Sat Sep 01 04:00:00 EDT 1979 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3575182· OSTI ID:5867719

Geraci, J P; Spence, A M

The effects of cyclotron neutrons and /sup 60/Co-..gamma.. rays on an ethylnitrosourea-induced rat astrocytoma transplanted to an intracerebral site in rats have been examined. Unirradiated tumor-bearing animals succumbed from the mass effects of relentless tumor growth 21 days after implantation of 5 x 10/sup 4/ cells with a survival-time range of 5 days. Single-dose, whole-brain neutron or photon irradiation 1 week after transplantation delayed the onset of neurological signs and prolonged survival. This response was dose-dependent with both types of radiation. However, neutrons were clearly more effective per rad resulting in an RBE of 3.0 to 3.5 at a neutron dose per fraction of 200 rad. Results using two and five daily fractions indicate that fractionation did not appreciably change the length of survival of the RBE value from that seen with single-dose experiments. Irradiation of tumors 2 weeks after transplantation did not change the mean survival time or the RBE values from those observed for tumors irradiated 1 week after transplantation. Histologically, the effects of irradiation appeared to be localized to the tumor site or tumor-involved brain tissue. Irradiated brain tissue remote from the tumor appeared normal histologically. Comparison of these results with other reports of normal central nervous tissue responses to fractionated neutron radiation in the clinical dose range suggests that there may be no advantage in using neutrons for the treatment of brain tumors.

• Research Organization: Univ. of Washington, Seattle
• OSTI ID: 5867719
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 79:3; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

560152* -- Radiation Effects on Animals-- Animals
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BARYONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
COBALT 60
COBALT ISOTOPES
DISEASES
DOSE-RESPONSE RELATIONSHIPS
ELEMENTARY PARTICLES
EXPERIMENTAL NEOPLASMS
FAST NEUTRONS
FERMIONS
HADRONS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
MEDICINE
MINUTES LIVING RADIOISOTOPES
NEOPLASMS
NERVOUS SYSTEM
NEUTRONS
NITROSO COMPOUNDS
NUCLEAR MEDICINE
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
RADIOISOTOPES
RADIOLOGY
RADIOTHERAPY
RATS
RBE
RODENTS
SURVIVAL TIME
THERAPY
VERTEBRATES
YEARS LIVING RADIOISOTOPES