Biological Effects of Ionising Radiation

Radio Sensitivity Radio Sensitive Tissues Radio Resistant Tissues

Radio Sensitive Tissues Reproductive cells of the ovary and the Testis Blood forming Tissues in bone marrow, spleen, lymph nodes Epithelium of the Skin Epithelium of the Intestinal Tract

Radio Resistant Tissues Bone Liver Kidney Muscle Nerves

Effects of Radiation Primary Effects occur when the initial interaction is with atoms in cells like those in DNA molecules. Secondary Effects occur with the formation of free radicals which are very reactive and can chemically attack molecules such as DNA.

Radiation Effects Stochastic Effects Non-Stochastic Effects

Stochastic Effects The probability of the effect increases with the dose. No established threshold. Examples: Cancer, Genetic Mutations

Non-Stochastic Effects (Deterministic) The severity of the effect increases with the dose. Generally a threshold exists. Below the threshold, no effects occur. Effects often result from the collective injury of many cells. Examples: Cataracts, Skin Burns, Lowering of Blood Cell Counts

Effects of Acute Radiation Exposure On the Blood On Digestion On the Central Nervous System

On the Blood Dose level between 200 and 1000 rad Damages red blood cell forming organs - loss of breath, tiredness Affects white blood cell production - reduced ability to fight infection Lowered platelet count - hemorrhaging and slower healing process Death by infection and hemorrhaging

On Digestion Dose level between 1000 and 5000 rad Stops new epithelial cells and absorption Nausea and vomiting Dehydration from diarrhea and low water absorption Electrolyte imbalance Death by Circulatory collapse from loss of fluids

Central Nervous System Dose Level greater than 5000 rad Convulsions Tremors Lethargy Death by respiratory/brain failure