Range of high LET effects from /sup 125/I decays
Track structure techniques are applied to calculate energy depositions in cylindrical targets 20 A in diameter (simulating the DNA duplex) containing, or near, /sup 125/I decays. Two problems are examined: (1) The possible effects of incorporated versus nonincorporated /sup 125/I are evaluated; (2) the extent of the radiological damage along the DNA is described and discussed for individual decays taking place in the DNA. The results of three different calculations are presented: (1) The distribution of the total energy deposited in the target per decay: Here it is shown that the /sup 125/I decays deposit considerably more energy than 5-MeV alpha particles when the decay occurs on the central axis of the cylinder. When the decay occurs at 40 A from the axis, the energy depositions are small and infrequent, showing that the iodine decay must occur within this distance to produce a high LET-like effect. (2) The distribution of average energy depositions around a curved cylinder simulating the DNA duplex encircling the nucleosome: There is a rapid decrease in the energy deposited in elements (of size resembling a base pair) away from the location of the decay. At approximately 17 A (approximately 5 bp) from the decay the mean energy deposited in an element is reduced by a factor of 10. (3) The energy deposited in individual elements of the cylinder is presented for single decays: The smooth decrease in average energy depositions with distance from the decay ((2) above) is not reflected in individual decays.
- Research Organization:
- MRC Radiobiology Unit, Chilton, England
- OSTI ID:
- 5006242
- Journal Information:
- Radiat. Res.; (United States), Vol. 2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
IODINE 125
LET
RADIOBIOLOGY
DECAY
DNA
BETA DECAY RADIOISOTOPES
BIOLOGY
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ENERGY TRANSFER
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
NUCLEI
NUCLEIC ACIDS
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
RADIOISOTOPES
560111* - Radiation Effects on Biochemicals- In Vitro- (-1987)