VPT 421: Veterinary Toxicology (2+0)

IRRADIATION-SENSITIVITY, HALF LIFE, EXPOSURE, ABSORPTION

Tissue Sensitivity to irradiation

• Very high - White blood cells (bone marrow), intestinal epithelium, reproductive cells
• High - Optic lens epithelium, esophageal epithelium, mucous membranes
• Medium - Glial cells of brain, lung, kidney, liver, thyroid, pancreatic epithelium
• Low - Mature red blood cells, muscle cells, mature bone and cartilage

Half – life

• Rate of decay of radioisotope
• This can range from very short to billions of years
• Half life of carbon is about 5730 years

Reducing exposure to radiation can be achieved by

• Time - Reduce the spent near the source of radiation.
• Distance - Increase the distance from the source of radiation.
• Shielding - Place shielding material between you and the source of radiation.

Absorption of Radiation

• Absorption of radiation is the prime consideration in radiation toxicology.
• Radiation can reach all tissues of the body directly from an external source, but the capacity to penetrate body tissues varies with the type of radiation.
• Radiation may be emitted as particles or as high-energy electromagnetic waves such as X-rays or gamma radiation.
• α-particles released by radionuclides are dangerous if they are taken into the body by inhalation (breathing in) and/or ingestion (eating and drinking).
• The adverse health effects caused by radon, an α -emitter, are explained by α -particles that are absorbed in the lung, thus becoming an internal radiation source.
• Indoor radon exposure can lead to lung cancer.
• Exposure from radon in drinking water is also of toxicological importance
• The depth to which ß-particles can penetrate the body depends upon their energy.
• When ß -emitters are taken into the body they irradiate internal tissues and become a more serious hazard.

Treatemnt

• There is no specific treatment. Treatment is only symptomatic.