Imaging in Inflammatory Disorders and Infection Flashcards
What are different kinds of molecular imaging?
Radionuclide imaging (CT/X ray)
Positron emission tomography (PET)
Magnetic resonance imaging (MRI)
Optical imaging
What is gamma radation?
Occurs due to radioactive decay of unstable isotopes
What is radiopharmaceuticals?
A combination of radioactive element and a pharmaceutical element
What are the properties of an ideal isotope?
Half-life similar to length of examination
Gamma emitter, rather than alpha or beta
Energy of gamma rays should be 50-300keV
Readily available at hospital site
Easily bound to pharmaceuitcal component
What are common radiopharmaceuticals?
Hydroxyl-diphosphonate (bone)
Dimercapto-succinic acid (kidney)
Hexamethyl-propine amine oxime (brain)
Macroaggregated albumin (lung)
What is hydroxyl-diphosphonate used to scan?
Bone
What is dimercapto-succinic acid used to scan?
Kidney
What is hexamethyl-propine amine oxime used to scan?
Brain
What is macroaggregated albumin used to scan?
Lung
What is a gamma camera used for?
To detect gamma rays and convert them into an image
What is the process of a gamma camera?
1) Nuclear energy is inside the nucleus of the radioactive element
2) Gamma electromagnetic energy (gamma ray is emitted from the patient)
3) Image crystal produces flashes of light
4) Converted into electrical energy to display an image
What does the image quality of a gamma camera depend on?
Radiation dose
Collimator
Metal objects
Proximity of area of interest to the camera
What is SPECT?
Single proton emission computed tomography
What is a SPECT scan?
A nuclear version of a CT scan where the camcer is roated around an area of interest
What does PET stand up for?
Positron emission tomography
What is a PET scan?
Uses nucleotide decay by positron emission
What does a proton breakdown into during a PET scan?
Proton breaks down into a neutron and a positron
How many detectors does a PET scan use?
2 detectors that capture the gamma ray at each side of the patient and are used to create an image
What are common PET radionuclides and their half lifes?
18F 110 minutes
11C 20 minutes
13N 10 minutes
15O 2 minutes
What is 18F?
Flurodeoxy glucose
What is the process of 18F (flurodeoxy glucose) uptake?
Up taken like glucose being broken down into similar chemicals, stopping at 18FDG-6-P (equivalent of glucose6-phosphate)
What is FDG taken up by?
Brain
Myocardium
Stomach
Liver
Spleen
Colon
Urinary tract
What is the main risk of using radiation?
It is ionising and can induce cancer
What is the benefit of using radiation?
The contributions to treatment and diagnosis of the patient
How does the equilvalent dose compare for different kinds of imaging?
They have different equivalent doses with different risks of developing cancer in your lifetime
