The Nowadays the use of modified compartmental model in order to estimate the transmission of tracer to the cells or cancerous tissues is focused extensively. The modified compartmental model includes two compartments, one to predict the mass transfer from vessels and a compartment to describe metabolism occurring inside the tissue. In the modified compartmental model, the kinetic rate constants can be obtained by estimating the parameters between the compartments. The accurate calculation (estimation) of rate factors over the region under study has an important role in coinciding the time activity curve obtained by compartmental modeling and the curve resulted from experimental data which is the main tool to distinguish the cancerous and normal tissues. Today most of doctors us the standard uptake value to study the amount of tracer uptake in cancer suspicious regions in order to have a more accurate recognition of cancerous and normal tissues. In this paper the Patlak graphical analysis method and standard uptake value (SUV) method are used to predict the tracer uptake into the tissue. A comparison between the uptake parameter resulted from the two mentioned methods with the uptake parameter obtained by modified compartmental model in a rat shows the accuracy of the Patlak method in distinguishing the cancerous tissues from the normal ones.