▁chemical s ▁are ▁l abeled ▁with ▁these ▁radio active ▁atoms . ▁The ▁l abeled ▁comp ound , ▁called ▁a ▁radi ot rac er , ▁is ▁inject ed ▁into ▁the ▁blood stream ▁and ▁eventually ▁makes ▁its ▁way ▁to ▁the ▁brain ▁through ▁blood ▁circul ation . ▁ ▁Det ectors ▁in ▁the ▁P ET ▁sc anner ▁detect ▁the ▁radio activity ▁as ▁the ▁comp ound ▁charges ▁in ▁various ▁regions ▁of ▁the ▁brain . ▁ ▁A ▁computer ▁uses ▁the ▁data ▁gathered ▁by ▁the ▁detect ors ▁to ▁create ▁multi - dimensional ▁( norm ally ▁ 3 - dimensional ▁vol um et ric ▁or ▁ 4 - dimensional ▁time - v ary ing ) ▁images ▁that ▁show ▁the ▁distribution ▁of ▁the ▁radi ot rac er ▁in ▁the ▁brain . ▁Es pecially ▁useful ▁are ▁a ▁wide ▁array ▁of ▁lig ands ▁used ▁to ▁map ▁different ▁aspects ▁of ▁ne uro trans mit ter ▁activity , ▁with ▁by ▁far ▁the ▁most ▁commonly ▁used ▁P ET ▁trac er ▁being ▁a ▁l abeled ▁form ▁of ▁gl uc ose , ▁such ▁as ▁fl ude ox y gl uc ose ▁( 1 8 F ). ▁ ▁Adv antages ▁and ▁dis adv antages ▁▁ ▁The ▁greatest ▁benefit ▁of ▁P ET ▁sc anning ▁is ▁that ▁different ▁comp ounds ▁can ▁show ▁flow ▁and ▁o xygen , ▁and ▁gl uc ose ▁met abol ism ▁in ▁the ▁t issues ▁of ▁the ▁working ▁brain . ▁ ▁These ▁measurements ▁reflect ▁the ▁amount ▁of ▁brain ▁activity ▁in ▁the ▁various ▁regions ▁of ▁the ▁brain ▁and ▁allow ▁to ▁learn ▁more ▁about ▁how ▁the ▁brain ▁works . ▁ ▁P