mechanism of localization in nm

Question 1

capillary blockade

Answer 1

mechanical obstruction of capilarries or precapillary arterioles in the lung (tc-MAA)

Question 1

phagocytosis

Answer 1

removal of foreign matter by physical entrapment ( tc-sc in RES)

Question 2

active transport

Answer 2

cellular metabolism concentrates RP in organ or tissue (I-123 NaI for thyroid f(x) and imaging)

Question 3

simple diffusion

Answer 3

movement of RP from area of [higher] to area of [lower] (breakdown of BBB allowing water soluble RP to penetrate brain in area of affected tissue

Question 4

cell sequestration

Answer 4

removal of damaged or old RBC’s from the circulation by the spleen; uptake of WBC’s infection site (Cr-53 RBC taken up by spleen or In-111 WBC sites of infection)

Question 5

compartmental localization

Answer 5

introduction of RP into well defined body compartment where it remains for an extended period of time (tc-dtpa aerosol; xe-133)

Question 6

antigen-antibody complex formation

Answer 6

radiolabeled antibody binds to tumor associated antigens (using tumor specific labeled antibodies to detect cancer or stage therapy)