PRINCIPLES OF TRACER METHODOLOGY 



Radioisotope In vivo study 



Testing of pulmonary resuscitative procedures 



Rate of disappearance from muscle 



Function of lymphatic system 



Effect of tourniquets 



Rates of mixing 



Blood flow through chambers of the heart 



Absorption from ointments 



Dissolving of coated capsules 



I'^' Thyroid function in normal and disease conditions 



Localization of metastases 



Localization of diiodofluorescein in brain tumors 

 Effects of antithyroid compounds 

 Absorption of insulin 

 Breakdown of fat molecules in humans 

 Diagnosis of metastatic cancer 



P^* Accumulation in foot after intravenous injection 



Liver accumulation of chromic phosphate 

 Effect of inhibitors on uptake by mussels 

 Uptake by tissue culture 

 Selective uptake in pathological skin areas 

 Selective uptake in breast, brain, and testis tumors 

 Rate of movement in plants 



K" Accumulation in hands after ingestion 



Uptake by tissue culture 

 Pattern of uptake by plants 



Br*2 Accumulation in hands after ingestion 



Uptake by abscesses 



Sr*' Bone accumulation 



Au"^ In connection with therapeutic use 



Kr*" Hand, leg, thigh, and knee measurements after inhalation; effects of 



temperature and various drugs 



C»» CO distribution 



Zn^^ Distribution pattern in humans 



GROSS RATES OF MOVEMENT 



The next logical extension of the studies mentioned above would 

 involve measurement of the rate of movement to provide information on 

 the dynamics of transfer of biological material. In animals considerable 

 attention has been given to estimation of the velocity of blood flow 

 through various tissues and organs. The circulation time, or rate of cir- 



