Mechanistic models
Several models and theories are reviewed that incorporate the idea of radiation-induced lesions (repairable and/or irreparable) that can be related to molecular lesions in the DNA molecule. Usually the DNA double-strand or chromatin break is suggested as the critical lesion. In the models, the shoulder on the low-LET survival curve is hypothesized as being due to one (or more) of the following three mechanisms: (1) interaction'' of lesions produced by statistically independent particle tracks; (2) nonlinear (i.e., linear-quadratic) increase in the yield of initial lesions, and (3) saturation of repair processes at high dose. Comparisons are made between the various approaches. Several significant advances in model development are discussed; in particular, a description of the matrix formulation of the Markov versions of the RMR and LPL models is given. The more advanced theories have incorporated statistical fluctuations in various aspects of the energy-loss and lesion-formation process. An important direction is the inclusion of physical and chemical processes into the formulations by incorporating relevant track structure theory (Monte Carlo track simulations) and chemical reactions of radiation-induced radicals. At the biological end, identification of repair genes and how they operate as well as a better understanding of how DNA misjoinings lead to lethal chromosome aberrations are needed for appropriate inclusion into the theories. More effort is necessary to model the complex end point of radiation-induced carcinogenesis.
- Research Organization:
- Lawrence Berkeley Lab., CA (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 5679976
- Report Number(s):
- LBL-31683; CONF-9009267-5; ON: DE92008293
- Resource Relation:
- Conference: Physical and chemical mechanisms in molecular radiation biology conference, Woods Hole, MA (United States), 3-7 Sep 1990
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
DNA
DAMAGE
BIOLOGICAL MODELS
CARCINOGENESIS
CHEMICAL REACTIONS
GENETIC RADIATION EFFECTS
IONIZING RADIATIONS
MATHEMATICAL MODELS
MONTE CARLO METHOD
SURVIVAL CURVES
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
GENETIC EFFECTS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PATHOGENESIS
RADIATION EFFECTS
RADIATIONS
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture
550400 - Genetics