WEEK 1 Flashcards
(22 cards)
What is the difference between Diagnostic Radiology and Therapeutic Radiology?
Diagnostic Radiology = uses various imaging modalities to aid in the diagnosis of disease
Therapeutic Radiology = uses radiation to treat diseases using a form of treatment called radiation therapy
What is a CT scan and what is it used for?
Computed Tomography (CT) is a type of imaging that uses x-rays to make cross sectional pictures of your body.
It is used to look out for broken bones, lungs, brain, cancers, blood clots, signs of heart disease, internal bleeding and any acute problem e.g bleeding & trauma
What is faster between a CT scan and an MRI?
CT (10-15sec) is FASTER than MRI (25-30min)
What is the history of the discovery of X-Rays?
In November 8 1895, Wilhelm Conrad Röntgen (a German professor) discovered while experimenting with cathode tubes a new penetrating radiation and called it “X-Rays”.
The first historical X-ray image was of the hand of his wife & he got a Nobel prize for physics in 1901.
Common equipment/techniques used in Diagnostic Radiology?
- CT (Computed Tomography)
- MRI (Magnetic Resonance Imaging)
- X-Ray
- Ultrasound
What is an X-ray?
X-rays are electromagnetic radiations which are used to create images of the subject/body
Why are X-ray images typically black and white?
X-ray images are black and white due to the different absorption of tissues
What tissue absorbs X-rays the most and what colour would the tissue be seen as?
Bones, they will be seen as WHITE since calcium in bones absorbs x-rays the most
What colour does healthy lungs appear in X-rays?
Black (because air absorbs X-rays the least)
How does an MRI work?
MRI uses a large magnet and radio waves to look at organs and structures inside the body
MRI is similar to a CT scanner in that produces __________ of the body
cross-sectional images
How does the CT machine work?
The x-rays are produced in a part of the ring and the ring is able to rotate around the patient and create images
Describe the radiography principle of image formation
- X-ray beam of uniform intensity falls on object which consists of structures with different absorption properties
- The different structures absorb the beam in different amounts
- The transmitted beam consists of different intensities called the “aerial image”
- The aerial image falls on the image receptor which translates to an image
What are the common uses of x-rays?
- Broken bones/Fractures
- Pneumonia
- Breast cancer
What is an MRI and what is it used for?
Magnetic Resonance Imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body
MRIs can be used for:
- Diagnosing tumours
- Bleeding
- Blood vessel diseases
- Infection
- Brain and spinal cord
- Abdomen and pelvis
- Bones and joints
What is another term for CT scan?
CAT scan
When did the first MRI machines become available?
1980s
What is the difference between T1 and T2 MRI?
T1 MRI is known as “Spin-lattice relaxation time” and differentiates fat from water (water appearing darker and fat appearing brighter). T1-weighted MRI is best for looking at brain structures.
T2 MRI is known as “Spin-spin relaxation time” and also differentiates from water but fat shows darker and water shows lighter. T2 is better for looking at non-enhancing brain lesions.
What is the strength of magnets used in both T1 and T2 MRI?
0.5-2.0 Tesla range
What are some limitations of using MRI?
- some patients experience claustrophobia
- some obese patients cannot be examined
- patients with pacemakers and metalwork cannot be examined
What is ultrasound and what is it used for?
Ultrasound is a type of imaging that uses high-frequency sound waves to look at organs and structures inside the body
Ultrasound is used to view the heart, blood vessels, organs, tissues and muscles
[ultrasound cannot see bones or lungs but can see muscles. structures cannot be seen under the bone since ultrasound cannot penetrate through the bones]
What frequencies are used in ultrasound diagnostics?
2-40 MHz with intensity of 1 kW/m^2
