Theoretical and observational analysis of individual ionizing particle effects in biological tissue
The microstructural damage to living tissue caused by heavy ion radiation was studied. Preliminary tests on rat corneal tissue, rat cerebellar tissue grown in culture, and rat retinal tissue indicated that the best assay for heavy ion damage is the rat cornea. The corneal tissue of the living rat was exposed to beams of carbon at 474 MeV/amu, neon at 8.5 MeV/amu, argon at 8.5 MeV/amu, silicon at 530 MeV/amu, iron at 500 MeV/amu, and iron at 600 MeV/amu. X-rays were also used on corneas to compare with the heavy ion irradiated corneas. Scanning electron microscopy revealed lesions with circular symmetry on the external plasma membranes of corneal epithelium which were irradiated with heavy ions, but similar lesions were not observed on the plasma membranes of x-ray irradiated or non-irradiated control samples. These data verify the special way in which heavy ions interact with matter: each ion interacts coulombically with electrons all along its trajectory to generate a track. The dose from heavy ion radiation is not distributed homogeneously on a tissue microstructural scale but is concentrated along the individual particle track. Even along a single particle track the dose is discontinuous except at the Bragg peak when the LET is maximum. Micrographs of heavy-ion-irradiated corneas demonstrated two significant correlations with the heavy ion beam: (1) the number of plasma membrane lesions per unit area was correlated with the particle fluence, and (2) the diameter of the lesions were linearly related to the energy loss or LET of the individual particle. These observations corroborate what has already been suggested theoretically about heavy ion tracks and what has been shown experimentally. But the new data indicate that particle tracks occur in biological tissues as well, and that a single heavy ion is responsible for each membrane lesion. (ERB)
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6759783
- Report Number(s):
- LBL-11147; TRN: 81-002086
- Resource Relation:
- Other Information: Thesis
- Country of Publication:
- United States
- Language:
- English
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CORNEA
BIOLOGICAL RADIATION EFFECTS
ARGON 40 BEAMS
CARBON 12 BEAMS
COMPARATIVE EVALUATIONS
ELECTRON MICROSCOPY
EXPERIMENTAL DATA
IRON 56 BEAMS
LET
LOCAL IRRADIATION
MEV RANGE 01-10
MEV RANGE 100-1000
NEON 20 BEAMS
PARTICLE TRACKS
RATS
SILICON 28 BEAMS
SPATIAL DOSE DISTRIBUTIONS
X RADIATION
ANIMALS
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BIOLOGICAL EFFECTS
BODY
BODY AREAS
DATA
ELECTROMAGNETIC RADIATION
ENERGY RANGE
ENERGY TRANSFER
EYES
FACE
HEAD
INFORMATION
ION BEAMS
IONIZING RADIATIONS
IRRADIATION
MAMMALS
MEV RANGE
MICROSCOPY
NUMERICAL DATA
ORGANS
RADIATION DOSE DISTRIBUTIONS
RADIATION EFFECTS
RADIATIONS
RODENTS
SENSE ORGANS
VERTEBRATES
560152* - Radiation Effects on Animals- Animals