Effects of fast neutrons on rabbits. II. Comparison of pathologic effects of fractionated neutron and photon exposures of the lung and spinal cord

Journal Article · Fri Jun 01 04:00:00 EDT 1979 · Int. J. Radiat. Oncol., Biol. Phys.; (United States)

DOI:https://doi.org/10.1016/0360-3016(79)90063-4· OSTI ID:5570436

Bradley, E W ^[1]; Zook, B C; Casarett, G W; Mossman, K L; Rogers, C C

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1. George Washington Univ. Medical Center, Washington, DC

Young adult rabbits were irradiated at high intensity twice weekly for 6 weeks to the cervical and thoracic spinal cord region (> 50% of lungs included in field); they were irradiated with photons (4 MeV) to 4 cumulative doses (from 4800 to 19,200 rad) or fast neutrons (15 MeV) to 4 cumulative doses (from 1680 to 6720 rad), with photon doses 2.86 times as large (assumed relative biological effectiveness) as corresponding neutron doses. The rabbits were observed especially for pulmonary and neurologic signs; when they became paralyzed or moribund, they were sacrificed for histopathologic study. Paraplegia occurred only after 6720 rad of photons or after neutron doses of 2520 rad or greater. Only in these rabbits were spinal cord lesions observed; they varied from occasional swollen axons to extensive necrosis and myelin loss, and were much more severe in the white than in the gray matter. Malignant bone tumors were found only in the irradiated field in 2 of the 3 rabbits receiving 2520 rad of neutrons. Radiation-induced lung changes were found in all irradiated rabbits, with the character of the lesions not depending upon dose but dependent on time after irradiation. Signs of severe respiratory diseases were seldom observed until just before death.

• OSTI ID: 5570436
• Journal Information: Int. J. Radiat. Oncol., Biol. Phys.; (United States), Journal Name: Int. J. Radiat. Oncol., Biol. Phys.; (United States) Vol. 5:6; ISSN IOBPD
• 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
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BODY
CARCINOGENESIS
CENTRAL NERVOUS SYSTEM
COMPARATIVE EVALUATIONS
DISEASES
DOSE RATES
DOSE-RESPONSE RELATIONSHIPS
EDEMA
ELEMENTARY PARTICLES
EXTERNAL IRRADIATION
FAST NEUTRONS
FERMIONS
FIBROSIS
FRACTIONATED IRRADIATION
HADRONS
IRRADIATION
LUNGS
MAMMALS
MASSLESS PARTICLES
MEDICINE
NECROSIS
NEOPLASMS
NERVOUS SYSTEM
NEUTRON THERAPY
NEUTRONS
NUCLEAR MEDICINE
NUCLEONS
ORGANS
PARTIAL BODY IRRADIATION
PATHOGENESIS
PATHOLOGICAL CHANGES
PHOTONS
RABBITS
RADIATION EFFECTS
RADIOINDUCTION
RADIOLOGY
RADIOTHERAPY
RESPIRATORY SYSTEM
SIDE EFFECTS
SPINAL CORD
SYMPTOMS
THERAPY
TIME DEPENDENCE
VERTEBRATES