ef? Page 2 Dowdy «= Therapeutic Apnvileasi ott wil isotopes be derived from their present theraneuti important thoush this epplicsation is, w.ather does it seem ths greatest advantese of ra€iowisotopes will core from their use as a ree Search tocl in pushine tack the frontiers of ence, ‘Their particular application in biology is in Yurtherins the ssudy of cell vhysiologr, As eonceri.s reéiation, > it is the ersunt of redieticon absorbed b ionization which produces biclogical reeoctians. radiction energy is abe sorbed in the tissues by the process of losizgaticn, Tue exect steps in the pnysicoechemicsl chanves resulting from these fonizations are not Kknoeno Problems yst to be solvec in the use cf controll: d nvelecr enerey deel chances resulting from expceure wo nirime {2} on selective ealteratior of tissus ecasitiviiw co various avpes of radiation, (3) protesticn of tissue epainss ths ¢elevertous efvects of radie ation, (4) finding a theraocutic meecure bo sm liori.te Jamase cnd hasten reccvery once demege hes ensued from racetion.