Screen used for X-ray exposure prevention, is made of-

Ans. is 'a' i.e., Lead * In x-ray facilities, walls surrounding the room with the x-ray generator may contain lead sheets, or the plaster may contain barium sulfate. Operators view the target through a leaded glass screen, or if they must remain in the same room as the target, wear lead aprons.* Lead is the most common agent used in modern constructions (Room design) to offer radiation shielding.Other Important facts about x-ray radiography* Filament (cathode) and Target (anode) are made of Tungsten. However, In mammography the target (anode) is made of Molybdenum or rhodium.* Most of the modern x-ray tubes have rotating anode because rotating anode have better heat dissipiation. The x-ray tube uses all three forms of cooling i.e., radiation, conduction and convection. However, radiation is most important.* X-ray grid is the part of x-ray machine that ensures the clarity of image on x-ray film, absorbs scattered x-rays and filters out radiations.* Filter is the device which absorbs low energy photons and there by decreases the radiation exposure to the patient. Filter is usually made of aluminium or aluminium copper combination.* Window is the part of x-ray machine through which the x-ray beam is emitted towards the patient.* Collimators are used to restrict the size of the x-ray beam, i.e., restriction of field size and decreases scatter radiation.* Film focus distance (the distance from x-ray tube target, i.e., anode to the x-ray film) is 100 cms (40 inches) for routine radiography. While for chest x-ray it is 180 cm (72 inches or 6 feet) to reduce magnification as short distance increases the magnification of body part.