Radiopharmacy Flashcards
What do isotopes have?
same number of protons
but different number of neutrons
at what form does isotope wants to be in?
in the most stable form
What results in radioactivity?
the rearrangement within the nuclue
What are the types of radiation?
alpha particles, beta particles, gamma rays, x-rays
Which radiation is used for diagnosis?
gamma radiation
- imaging, non-imaging
What makes gamma radiation a good diagnostic tool
it has a very good fast penetration
Which radiation is used for therapy?
beta radiation (esp for brain/thyroid cancer)
What are the examples of radiopharmaceuticals?
Technetium 99m- based
others
for PET scan
What is technetium 99m?
it decays by isomeric transition
with physical half life of short, 6 hours
They are readily available from a generator
Is technetium 99m chemically versatile?
yes
so it is easy to stick it with many chemicals like ligands
What is the use of technetium-99m?
TC-radiopharmacetual ‘cold’ kits
The kit allows them to make radioactive ligands
What does the kit include?
inert gas, reducing agent, stabiliser, ligand
What are the kits used for?
We have many kits for different purposes
eg. bone/brain/heart/liver imaging, kidney function/structure, hepatobiliary imaging, lymph node imaging, RBC/WBC labelling
What beta emitters are used in what treatments?
iodine - thyroid (also gamma)
What are positron emitters?
18F, 11C, 15O
unusual isotope for carbon, oxygen
What is PET used for?
imaging cellular and molecular events (proliferation, oxygen metabolism, tumour receptor density, bone remodelling)
What do you need for PET?
close access to CYCLOTRON
it accelerates charged particles for collision to make radioactive isotopes
15O, 13N, 11C, 18F
What are the tracers in PET?
FDG = glucose
FLT = thymidine (nucleic acid)
18F
What is FDG used for?
targets GLUT tumour marker (increased glucose transporter)
What is FLT used for?
Targets DNA synthesis, thymidine kinase
Visualisation of cells undergoing DNA replication
What is 18F used for?
Targets hydroxyapatite crystals
(fluorine is for bones)
Visualisation of bone reaction to tumours
Increase in FDG in which part of the body may indicate cancer?
head, neck
liver, kidney, urinary tract, bladder, heart and brain always have glucose
Increase in FLT in which part of the body may indicate cancer?
Brain, heart
What is the new technique for screening?
PET + MRI (both structural and functional)
AA tracer for PET –>AMT (identify which cells are making proteins)
What are the Radiopharmaceutical quality controls
Radionuclidic/radiochemical/chemical.biological purity, radioactivity administered (accuracy of dose calibrator units)
Drug ineractions
TPN
decreases gall bladder activity
Aluminium (e.g antacids)
Safety - limiting exposure
ALARA, dose monitoring, spill kits, limit expose