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Biological Effects of Radiation. nonionizing radiation : bumps e – to higher energy levels or heats molecules; . less dangerous. ionizing radiation : knocks e – out of molecules; . more dangerous. a , b , g , x-rays, high-frequency UV. -- e.g., .
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Biological Effects of Radiation nonionizing radiation: bumps e– to higher energy levels or heats molecules; less dangerous ionizing radiation: knocks e– out of molecules; more dangerous a, b, g, x-rays, high-frequency UV -- e.g.,
H2O+ + H2O H3O+ + OH : : ( O–H) . -- sequence of action in living tissue (1) creates H2O+ (2) neutral free-radical w/unpaired e– The free-radical initiates a number of chemical rxns. that disrupt cell function. -- the tissues most damaged by radiation are the ones with cells that rapidly reproduce: bone marrow, lymph nodes -- low doses over a long time can induce cancer, which is… the uncontrolled reproduction of cells.
“radiation absorbed dose” “roentgen equivalent – man” Units for Radiation Doses 1 bequerel (Bq) = 1 disintegration/sec 1 Curie (Ci) = 3.7 x 1010 disintegrations/sec 1 gray (Gy) = absorbing 1 J/kg of tissue 1 rad = absorbing 1 x 10–2 J/kg of tissue Since the various types of radiation damage tissue with various degrees of efficiency, each type has its own relative biological effectiveness (RBE). photon or b RBE = 1 rem = RBE x rad n0 RBE = 10 a RBE = 20
radon formed this, too, is an a-emitter radon emits a radiation -- estimated to be responsible for ____ of U.S. lung cancer deaths 10% Radon -- an a-emitter from the decay of radium in rocks and soil -- very dense; seeps into basements and is readily inhaled a a Ra-226 Rn-222 Po-218