1. Eleventh lecture

2. II-internal radiation hazards A-Modes of entry Internal radiation exposure results from the deposition of radioactive material within the body through: Inhalation. Ingestion. Self innoculation. Skin absorption.

3. Inhalation For materials capable of being airborne, inhalation is one of the principal potential modes of entry into the body. The absorption, retention, and elimination of material taken in via the lungs depends on: -the particle size of the inhaled material. -the solubility of the material. -the respiration rate.

4. ingestion Ingestion of radionuclides can cause a significant internal radiation hazard in the gastrointestinal tract. radionuclides can enter the body by absorption of ingested material. The percentage of ingested material absorbed by bloodstream depends on its:- i- Chemical properties ii- physical properties

5. Skin absorption Radioactive material can enter the bloodstream by absorption through:- i- the unbroken skin. ii-through abrasions. iii-cuts. iv-and other openings in the skin. Certain solvents may greatly enhance absorption through skin.

6. Self-innoculation Operation involving:- i-hypodermic needles, ii-Pasteur pipettes, iii-or other sharp instruments may lead to interior deposition of radioactive material via self-innoculation

7. II-Internal radiation hazards B-prevention of exposure: Internally deposited radioactive material produces continuous exposure until it decays or is removed from the body by metabolic processes. Therefore, the factors of time, distance and shielding can’t applied. Prevention Internal of exposure is based on the principles of: containment. cleanliness.

8. containment Is the first line of defense against internal radiation hazards. It means preventing contamination as well as controlling the spread of contamination should it occurs. It can be accomplished by using appropriate equipment correctly and by developing proper operating techniques.

9. containment It consists of three basic elements: i-control of the radioactive material at the source to prevent release into the worker‘s environment. ii-Reduction of the consequences of accidental release of radioactive material into the environment. iii-Protection of the worker from contact with the material in the event he is in contaminated environment.

10. cleanliness Proper operating techniques must be supplemented by cleanliness and good housekeeping to minimize the spread of contamination. It involves: i- regular monitoring of equipment, personnel, and operating techniques. ii- regular checking of working surfaces, floors and all other surfaces.