Radiopharmacy Flashcards
In order to prescribe radoopharmaceuticals doctors must have what?
RSAC approval - not all dr’s can prescribe radioactive medicines
Alpha decay
ejects a doubly charged helium nucleus He2+
Beta decay
Excess neutrons gain stability by converting neutron to a proton and negatron (nuclear or beta particle)
Gamma decay
No particles emitted only gamma photons
Compare nuclear medicine and X-rays
Nuclear medicines - isotopes are emitted from the inside of the patient. Isotopes show function and show change as it happens
X-rays pass through the product, and show structure only. Only show changes post event . DO NOT show function
What is a gamma camera?
Detects gamma radiation. Consists of a collimator - absorbs scatter to give a clearer image by blocking waves that are coming off at angles.
Sodium iodide crystal produces a light response. This equivalent energy is then detected and measured.
What is the most widely used radionuclide?
99M Technetium
Discuss the properties of Tc99m
140 Kev energy
6 hour half life - completely gone within 2 days
Easily detected using a gamma camera
Easy to manufacture and readily available
Low energy range
Decays to stable isotope
Combines with a wide range of targeting tracers (due to its many oxidation states giving it different properties)
What are the key differences between aseptic services and radiopharmacy?
No prescription needed for radionuclide
Aseptic technique - operator safety is important. Doubling the distance will decrease the exposure by a square root.
Legislation
- H&S radiation protection
- environmental radioactive substances act (cannot vent externally w/o filtering first)
- transport –> radioactive materials road transport act.
Purchasing and contracts - when ordering need to specify exactly when you want it for so can account for the half life and decay.
What quality control is used in radiopharmacy?
Radiochemical purity
Chromatography
What radionuclide is used in a kidney scan?
DMSA - dinercaotisuccinic acid
Passes through glomerulus but reabsorbed in distal tubules
Function and renal outline
Renal scarring - can give the impression that the kidney is still functioning well
Used extensively in paediatric nephrology
What is the difference between a V and a Q lung scan?
V = ventilation
- aerosol used
- inhaled krypton 81 gas
- compare image with perfusion
Perfusion
- inject MAA (macroaggregates alubumin)
- cold spots if no perfusion
What is pertechnetate (TcO4) used for?
Thyroid imaging
and
Stomach - meckels diverticulum
How can colloids be used?
Particle size denotes usage Liver colloids - not used now replaced by CT scan Bone marrow and lymphatics Standard lymphoscintigraphy Sentinel lode localisation
