Weel 4: Diagnostic methods + techniques part 2 Flashcards
1
Q
Positron Emission Tomography (PET)
A
- A short half-life positron-emitting isotope attached to a biologically active molecule is injected into the patient, which is then monitored with a detector by coincidence as annihilation energies are released
2
Q
Examples of radiotracers for PET
A
- Most common are Carbon-11 and Fluorine-18
3
Q
PET/CT
A
- Currently, all commercial systems are now integrated with PET/CT scanners
- Gives improved accuracy in attenuation correction + image fusion of morphologies + functional death
- A major downside is the mismatch between data acquisiton times, with the image acquisiton being within seconds for CT multi-slices, but several minutes with PET
4
Q
Clinical applications of PET/CT
A
- Oncology
- Neurology
- Cardiology
5
Q
Magnetic Resonance Imaging (MRI)
A
- Provides a spatial map of the protons in H2O + lipid in different tissues
- Image intensity is dependent on the number of protons in any spatial location, as well as physical properties of the tissue ie viscosity, stiffness, protein content
- One of the few imaging modalities that don’t use ionising radiation of any sort
6
Q
MRI contrast agents
A
- 2 types:
+ Paramagnetic contrast agents
+ Supermagnetic contrast agents
7
Q
Paramagnetic contrast agents
A
Shortens T1 of the tissue in which they accumulate, increasing MRI signal on T1-weighted scans
8
Q
Supermagnetic contrast agents
A
Reduces the MRI signal in tissues in which they accumulate. Causes very fast T2 relacation. reduces the signal intensity from healthy tissue, with tumors remaining unaffected + as a relatively bright area
9
Q
Clinical applications of MRI
A
- Almost all parts of the body are imaged in the clinical setting:
+ Brain + spinal cord
+ Entire musculoskeletal system
+ MR immunography
+ Body imaging of liver, kidneys, urinary tract + prostate
+ Cardiological applications looking at heart disease
+ Muscoloskeletal applications
