Imaging Flashcards
What is an xray?
An electromagnetic packet of energy with a extremely short wavelength .
How short is the wavelength for xrays?
Between 0.1 and 10 nanometres
What is one of the main problems with xray generation?
Produces a lot of heat
What does the intensity of xrays depend on?
Tube current
Atomic number of target
Tube voltage
What are the three xray interactions with matter?
Absorption
Transmission
Scatter
Define attenuation.
The process by which radiation loses power as it travels through matter and interacts with it.
Name three factors which increase attenuation.
Increases with Z (atomic number)
Increases with density
Increases with thickness
What helps with the generation of an ultrasound?
Sound waves
List some of the features of an MRI machine
-Rotating x-ray tube
-Multiple beams
-Single axis of rotation
-Digital geometry processing….axial image
List some applications for CT
Trauma
Cancer staging and response to treatment
Guidance for procedures
Define ionising radiation.
A particle or wave with sufficient energy to ‘ionise’ a neutral atom or molecule, and leave them with either a positive or negative charge.
What is the unit used for describing the absorption of radiation by the human body?
Sievert
Name three ways to minimise exposure to raditiation.
- minimise time
- use shields
- distance yourself
MRI is useful for examining which two parts of the body v well?
Brain and spinal cord
Name some imaging
Plain radiographs
Barium studies
CT
MRI
PET
What is a barium xray?
A barium X-ray is a radiographic (X-ray) examination of the gastrointestinal (GI) tract.
What parts of the body is the barium swallow and meal for?
Oesophagus, stomach and duodenum
What part of the body is the barium follow through used for?
Small intestine
What part of the body is the barium enema used for?
The large bowel
Name the cross sectional imaging used for the diagnosis of cancer.
PET
CT
MRI
When is CT used in cancer imaging?
CT is used in the initial diagnosis staging of the disease
List some of the things that can be highlighted from a CT.
-Biopsy of the lesions
- Monitoring response to treatment
- Evaluation of residual mass after treatment
- Recognition of complications of treatment
- When there is concern for disease relapse
Explain the scientific basis of magnetic resonance imaging (MRI)
->it’s one of the learning outcomes I’M SORRY
Radiofrequency pulse displaces protons and images created by displaying time taken for protons to “relax” back to the original alignment.
What is MRI very good at showing?
The detail of bone soft tissue
Name some of the areas MRI is useful in imaging.
Brain, spine and musculoskeletal
abdomen and pelvis
cardiac imaging
List some disadvantages of MRI.
Brain, spine and musculoskeletal
abdomen and pelvis
cardiac imaging
Name the advantage for screening.
Diagnose disease at an earlier stage, before symptoms start meaning things like cancer is easier to treat and most likely to be curable
List some of the screening carried out by the NHS.
Breast
Bowel
Cervix
Name various principles The condition should be an important health
problem.
The condition should be an important health problem.
There should be a latent stage of the disease.
There should be a test or examination for the condition.
The test should be acceptable to the population There should be a treatment for the condition.
Facilities for diagnosis and treatment should be available.
What is the screening for breast cancer?
Mammography screening
Explain that imaging investigations can be expensive and should only be requested when appropriate.
Benefit to the individual and the population should outweigh the cost
What is molecular imaging?
Radionuclide imaging
Name the most frequenty used type of molecular imaging.
PET
Name the two elements of radiopharmaceuticals
Radioactive element
+
Pharmaceutical element
List some of the properties of an ideal isotope.
-Half-life similar to length of examination
-Gamma emitter, rather than a or b
-Energy of g rays should be 50-300 keV
-Radionuclide should be readily available at hospital site
-Easily bound to pharmaceutical component
-Radiopharmaceutical should be simple to prepare
-Radiopharmaceutical should be eliminated in similar half-time to duration of examination
What is a gamma camera used for?
Used to image gamma radiation–emitting radioisotopes.
What is SPECT usually used for?
brain and cardiac studies
What is SPECT?
CT version of nuclear medicine where gamma cameras rotate around area of interest
What type of imagining is PET?
Molecular imaging
Learning outcome says- Examples of inflammatory and infectious diseases
…so ig give some examples of inflammation?
- aortitis (inflammation of the aorta).
-ulcerative colitis (a long-term condition where the colon and rectum become inflamed)
Describe the main risk of ionising radiation.
Risk of inducing fatal cancer e.g. CT abdomen & pelvis = 1:1600 (but risk is 1:4 for population and risk is relative)
Describe the benefits of ionising radiation.
diagnosis, management change, treatment) should always outweigh costs (radiation, risk to patient and staff, ££)
idk this is what he said
