okok Flashcards
What is nuclear medicine?
Medical specialty involving the application of radioactive substances in the diagnosis and treatment of disease.
What governs the uptake of a radioactive tracer?
Physiology.
What does the contrast in nuclear medicine images depend on?
Relative uptake of tracer between the organ of interest and the background.
What type of information does nuclear medicine provide?
Information about the function of an organ.
What is the spatial resolution of nuclear medicine?
Relatively poor.
Is nuclear medicine a high dose procedure?
Yes.
What are radiopharmaceuticals composed of?
Radionuclide and pharmaceutical.
What role does a radiopharmaceutical play in the body?
Acts as a tracer for a particular physiologic or chemical process.
What is Technetium-99m used for?
Most commonly used radionuclide for diagnostic imaging.
What is the half-life of Technetium-99m?
6 hours.
What is Technetium-99m produced from?
Decay of Molybdenum-99 (99Mo).
What is the half-life of Molybdenum-99?
28 days.
How is Molybdenum-99 produced?
By neutron irradiation of Molybdenum-98 or extracted from fission products.
What is the purpose of the Technetium-99m generator?
To elute Technetium-99m from Molybdenum-99.
What is the elution process in the Technetium-99m generator?
Technetium-99m is eluted from alumina by passing sterile saline through it.
What is sodium pertechnetate (NaTcO4)?
The resulting eluate from the Technetium-99m generator.
What are common radiopharmaceuticals used in nuclear medicine?
- Bone scan
- Lung scan
- Myocardial perfusion imaging
- Kidney imaging.
What does a gamma camera do?
Detects gamma rays emitted from radiopharmaceuticals.
What is the function of the collimator in a gamma camera?
Controls the gamma rays reaching the scintillation detector.
How are gamma rays converted in gamma cameras?
Into flashes of light by the scintillation crystal.
What transforms light into electrical signals in gamma cameras?
An array of photomultiplier tubes (PMT).
What do the X and Y signals in gamma cameras represent?
The spatial location of the scintillation.
What does the Z signal in gamma cameras represent?
The energy deposited in the crystal by the gamma ray.
What is the most common type of collimator in gamma cameras?
Parallel hole collimator.
What determines the properties of a collimator?
The thickness and length of the lead septa separating the holes.
What is the compromise in collimator performance?
Between spatial resolution and sensitivity.
What is spatial resolution in collimators?
The ability to distinguish two small sources of radioactivity close to each other.
What is sensitivity in collimators?
A measure of gamma rays incident on the collimator that pass through to the detector.
What is the scintillation crystal made of?
Thin crystal of sodium iodide, doped with thallium (NaI(Tl)).
What happens when a photon interacts with the scintillation crystal?
It emits a photon of visible light by the process of scintillation.
What is the function of photomultiplier tubes (PMTs)?
Detect small amounts of light produced in scintillation.
What is the purpose of dynodes in PMTs?
To accelerate electrons and amplify the signal.
How does the distance from scintillation affect PMT output?
Closer tubes produce a larger amount of light.
What does the sum of pulse heights in PMTs represent?
The total amount of light produced.
What are CZT gamma cameras known for?
Improved energy resolution.
What is unique about pixelization in CZT cameras?
Each hole in the collimator aligns with a single corresponding detector pixel.
What is the benefit of registered collimation in CZT cameras?
Simplifies localization of events detected within a single tiny pixel.
What are novel camera designs in nuclear medicine?
Spectrum Dynamics with 12 CZT detectors in a 360° configuration.
