RADIATION HAZARDS&PROTECTION DR SAMY I ALAGHA A.PROFESSOR OF RADIOLOGY ALAZHAR GAZA UNIVERCITY

EFFECT OF RADIATION 1-DIRECT EFFECT: The energy of x-ray photons is directly transferred to biological macromolecules 2-INDIRECT EFFECT: The energy of x-ray photons is absorbed by water in a biological system

RADIOLYSIS OF WATER H2O + X-RAY >>>>>H+ + OH- (Free radical) H + O2(In tissues)>>>HO2(Hydroperoxyl radical) HO2 + H >>>>H2O2(Hydrogen peroxide)

RADIATION UNITS 1-Roentgen (R) Unit of X-ray exposure 2-Rad Unit of absorbed dose 3-Rem Unit of biological damaging effect

RADIATION UNITS Traditional units S I UNITSConversions ExposureRoentgenCoulomb/kg (c/kg) 1C/kg=3876 R ABSORBED DOSE RadGray(Gy)1Gy=100Rad Biological effect RemSievert(Sv)1sv=100Rem RADIOACTIV ITY Curie(Ci)Bequerel(Bq)1bq=2,7x Ci

Radiation Effect on oral tissue A-Short term effect Depend on sensitivity of cells B-Long term effect Fine vessels>>swelling>>>>degeneration&necrosis >>>progressive fibrosis>>>narrowing&oblitration of vascular lumen

EFFECT OF RADIATION ON ORAL TISSUE 1-ORAL MUCOUS MEMBRANE AFTER 2 WS OF RADIATION>>Mucositis(redness) Later >>>white/yellow pseudomembrane>>>severe discomfort&difficut food intake  Good oral hygiene as socondry infection(candida)  Healing after 2 months  On long term>>>atrophy of MM

EFFECT OF RADIATION ON ORAL TISSUE 2-TASTE BUDS  Radiotherapy>>>degeneration of taste buds>>> Loss of taste(in 2 nd or 3 rd week}  Recovery 2-4 months after radiotherapy

EFFECT OF RADIATION ON ORAL TISSUE 3-SALIVARY GLANDS  Within few ws of radiotherapy>>>loss of salivary secretion>>>dry mouth(xerostomia)>>tender mouth&difficult swallowing  After 6-12 months >>improvement due to compunsatory hypertrophy.  Xerostomia for more than 1y>>no recovery

EFFECT OF RADIATION ON ORAL TISSUE 4-TEETH  Adult teeth are resistant to radiation effect  Pulpal tissues undego fibro-atrophy  Radiotherapy in children>>>retarted growth  Radiotherapy before calcification>>destroy tooth bud  Radiotherapy after calcification>>>malformation of teeth

EFFECT OF RADIATION ON ORAL TISSUE 5-RADIATION CARIES This is due to less saliva and decrease PH &increase viscosity of saliva This is treated by topical 1%sodium fluoride gel

EFFECT OF RADIATION ON ORAL TISSUE 6-BONE  Radiation induced fine vasculitis>>>bone infection &necrosis especially after teeth extraction  Osteo-radionecrosis occurs more in mandible than maxilla  In oseo-radionecrosis >>defined border between necrotic and normal bone without subperiosteal new bone formation  Post radiotherapy teeth extraction should be avoided

X-RAY PROTECTION THIS IS DONE BY 1-Safe equipment 2-Proper technique 3-Professional judgement

SAFE EQUIPMENT 1-Filtration 2-Collimation 3-Timer 4-Cones:opened ended &closed ended 5-Film speed 6-Leaded apron&thyroid collars 7-Film hold device

PROPER TECHNIQUE 1-Proper film placement 2-Proper x-ray adjustment 3-Proper processing

PROFESSIONAL JUDGMENT

OPERATOR PROTECTION 1-Protection from 1ry radiation 2-Protection from 2ry radiation 3-Protection from leakage radiation

ENVIRONS PROTECTION  They include secretaries and cleaners  Maximum permissible dose (M.P.D)=0.5rem/y  Protection is achieved by: 1-Shields 2-radiation survey&monitoring 3-1ry beam direction&patient position

END