MEDRADSC 2X03 Lecture Notes - Lecture 10: Hypoplasia, Denudation, Total Body Irradiation
12 Mar 2017
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Document Summary
Effect on tissues because: cell death is different from the effect due to cell mutation with clonogenic capacity. If number of dead cells is very small: no visible effect. If sufficiently large number of cells are affected result is loss of tissue function: ***dose-dependent magnitude of effect on tissue**, threshold dose exists. Increase the likelihood it happens, increase severity: has practical dose threshold, below threshold: no visible effect, above threshold, probability of effect increases rapidly with dose, severity of effect increases with dose (cataractogenesis) Stochastic effect: has no threshold dose, probability of effect increases with dose, severity of effect is not dose-related, carcinogenesis, hereditary effects. Latent period: time gap between irradiation and time of expression of biological effect, solid tumours have very long latent period (10-60 years) Effects on tissue systems and organs: other than for carcinogenesis and hereditary effects, tissue and organ response is deterministic, severity of response increases with dose.
