Exposure Routes Internal and External Exposure External exposure - PowerPoint PPT Presentation

Exposure Routes Internal and External Exposure External exposure Internal exposure Body surface From outer space contamination and the sun Inhalation Suspended Food and drink matters consumption Lungs From a radiation generator Radio‐ pharmaceuticals Wound Buildings Ground  Radiation coming from outside the body  Radiation emitted within the body Radioactive The body is equally exposed to radiation in both cases. materials

Exposure Routes Various Forms of Exposure External exposure • Whole‐body exposure • Local exposure (e.g. exposure by X‐ray examination or local body surface contamination) Radioactive materials Internal exposure • Whole‐body exposure • Local exposure (e.g. exposure from the thyroid taking in radioactive iodine)

Exposure Routes External Exposure and Skin Skin structure Outside Part highly sensitive β‐particle the body γ‐ray to radiation α‐particle γ‐rays β‐particles α‐particle Hair Within Stratum corneum the body Epidermis Basal cells About Affected part 0.2mm Dermis Subcutaneous structure

Exposure Routes Internal Exposure (i) Ingestion From the mouth (swallowing) Inhalation or ingestion Absorption through the digestive Radioactive materials Radioactive materials tract within the body decay within the body decay (ii) Inhalation as they emit radiation as they emit radiation Nose Incorporation from the respiratory within the body. within the body. airways Thyroid Mouth Absorption from the lungs and the surface of the airways From (iii) Percutaneous absorption Lungs the skin Absorption from the skin They may They may (iv) Wound contamination accumulate in some accumulate in some Contamination from a wound Wound specific organs. specific organs. They are gradually excreted Radioactive material in the urine and feces.

Internal Exposure and Radioactive Materials Exposure Routes The characteristics of radioactive materials that especially cause problems in internal exposure (i) α‐emitters > β‐emitters or γ‐emitters (ii) Materials that enter easily but are difficult to excrete (iii) Materials that are likely to accumulate in specific organs Radioactive materials