issue ▁( lim iting ▁the ▁effect ▁on ▁nearby ▁health y ▁t issue ), ▁such ▁as ▁b ism uth - 2 1 3 ▁or ▁act in ium - 2 2 5 ▁l abeled ▁D OT AT OC ▁are ▁of ▁particular ▁interest . ▁ ▁D os imet ry ▁Th era pe ut ic ▁PR RT ▁treat ments ▁typically ▁involve ▁several ▁gig ab ec quer els ▁( GB q ) ▁of ▁activity . ▁Several ▁radi oph arma ce ut ical s ▁allow ▁simultane ous ▁imag ing ▁and ▁ther apy , ▁en abling ▁precise ▁dos imet ric ▁estimates ▁to ▁be ▁made . ▁For ▁example , ▁the ▁bre ms stra hl ung ▁emission ▁from ▁ 9 0 Y ▁and ▁g amma ▁em issions ▁from ▁ 1 7 7 Lu ▁can ▁be ▁detected ▁by ▁a ▁g amma ▁camera . ▁In ▁other ▁cases , ▁imag ing ▁can ▁be ▁performed ▁by ▁lab elling ▁a ▁suitable ▁rad ion uclide ▁to ▁the ▁same ▁pe pt ide ▁as ▁used ▁for ▁ther apy . ▁Rad ion u cl ides ▁that ▁can ▁be ▁used ▁for ▁imag ing ▁include ▁gal li um - 6 8 , ▁te ch net ium - 9 9 m ▁and ▁flu or ine - 1 8 . ▁ ▁Currently ▁used ▁pe pt ides ▁can ▁result ▁in ▁high ▁kid ney ▁dos es , ▁as ▁the ▁radi oph arma ce ut ical ▁is ▁retained ▁for ▁relatively ▁long ▁periods . ▁Ren al ▁protection ▁is ▁therefore ▁used ▁in ▁some ▁cases , ▁taking ▁the ▁form ▁of ▁alternative ▁subst ances ▁that ▁reduce ▁the ▁u pt ake ▁of ▁the