Pharmaceutical and Radiopharmaceutical Agents- Domain 3

Mo99/Tc99m generator

• most widely used generator in nuclear medicine, providing the short-lived 99mTc for various diagnostic and therapeutic procedures. 

• The parent 99Mo decays to 99mTc, which has a half-life of 6 hours, making it ideal for many imaging procedures. 

• The 99Mo is adsorbed on an alumina column, and the 99mTc is eluated (extracted) using saline solution. 

• Two types of commercial generators are available: wet and dry systems. 

Sr82/Rb82 generator

used for cardiac imaging

Ge68/Ga68 generator

used for PET imaging

transient equilibrium (generators)

occurs when the half-life of the parent (T1) is not much longer than that of the daughter (T2) (e.g., decay of 99Mo to 99mTc)

secular equilibrium (generators)

• Occurs when the daughter's half-life is significantly shorter than the parent's, meaning the parent's decay is essentially negligible during the daughter's buildup. 

• The daughter's activity will increase and eventually reach an equilibrium where it's approximately equal to the parent's activity. 

• In secular equilibrium, the daughter's activity decays at the same rate as the parent, essentially mirroring the parent's activity. 

generator yield

The amount of radioactive daughter material (like Tc-99m) that can be eluted (or "milked") from a radionuclide generator at a given time.

theoretical yield formula

Actual Yield (%) = (Activity eluted ÷ Theoretical maximum activity) × 100

eluate

the solution collected after the elution process, which is the act of extracting a daughter radioisotope from a parent-daughter radionuclide generator

99Mo/99mTc (99Mo breakthrough and Al +3 content)

0.15 uCi Mo99 per 1 mCi Tc99m, and <10ug/mL Al +3 content (strip turns pink)

82Sr/82Rb (measured activity & levels of 82Sr& 85Sr)

0.02 mCi Sr82 per 1 mCi Rb82 , & 0.2 mCi Sr85 per 1 mCi Rb82 limit

dose calibrator operation

an ionization chamber that measures the activity of a radioactive sample

DMSA

85% for qc

light sensitive, keep refrigerated before kit prep

clear

HMPAO

80% for qc

methylene blue added for stabilizer (4 hrs), refrigerate before kit prep, without stabilizer only good for 30 min

yellow- diluted pee color

Pertecnetate

95% for qc

oxidation state is +7

clear

Sulfur Colloid

92% for qc

boil for 5 min, particles must be 0.0-1 um

gelatin is used to stabilize, should not see particles

clear

Sestamibi

90% for qc

boiled for 20-25 min, cool for 1-3 min

clear

Myoview

90% for qc

add saline before Tc, refrigerate prior to kit prep

clear

PYP

90% for qc

refrigerate prior to prep

clear

ECD, Neurolite

90% for qc

use within 6 hours

clear

MAA

90% for qc

particles no larger than 4 squares under microscope, 10-90 um, refrigerate

turbid/white/opaque/foamy

Choletec

90% for qc

18 hr shelf life

clear to slightly opaque, may foam up

MDP/HDP

90% for qc

add absorbic acid to prevent oxidation, shake kits

clear

MAG3

90% for qc

boiled for 15-25 min, went, Sep-Pak used for qc, light sensitive

clear

Ceretec for WBC

80% for qc

do not add cobalt stabilizer, solution is stable for 30 min

clear

DTPA

90% for qc

Antioxidants added to prevent oxidation (ascorbic acid)

clear