Intro to Medical Imagining Flashcards
What is Radiology ?
Branch of medicine concerned with the use of radiant energy or radioactive material in diagnosis and treatment of disease.
What is the difference between a radiology and a radiographer ?
Radiologist:
-Specially trained Dr to interpret diagnostic images and perform ultrasonography
Radiographer: Healthcare professional trained to take X-ray, MRI or CT Scan (if also ultrasound then sonographer)
What is an interventional radiologist ? What are examples of procedures do they undertake ?
Radiologist who specialises in utilising minimally invasive image guided procedures to diagnose and treat diseases. Such procedures include angioplasty, stenting, biopsies (often use needles, catheters or wires).
What is a radiation oncologist ?
Specialist physician using ionising radiation in treatment of cancer.
What are the different kinds of medical imaging ?
- Conventional X-ray
- Computerized Tomography
- Nuclear Medicine
- Magnetic Resonance Imaging
- Ultrasound imaginig
How do x-rays work ?
By focusing beam of high energy electron in x-ray tube onto tungsten target.
What is the name of the image produced by X-Ray ?
Radiograph
How do tissues of high density appear on X-rays ? Why ?
They appear light grey/white because they cause more x-ray beam attenuation.
What are the 5 principle densities on a plain radiograph ?
Black: Air (lungs, bowel)
Dark grey: Fat (subcutaneous tissue layer)
Light grey: Soft Tissues/water (solid organs…)
Off White: Bone
White: Metal/contrast material
How many planes does X ray uses ?
It it best done using 2 planes including joint below and above the area of concerned (usually anteroposterior and lateral radiography in trauma)
What is the difference between lateral, PA and AP radiography ?
Lateral:
-X-ray passes through thorax from side to reach x-ray film adjacent to person’s other side
PA:
- X-rays pass through thorax from back to reach x-ray film anterior to person
- usually performed
AP:
- projection from front
- performed if patient is unwell (and is lying down)
What is a problem with switching from AP to PA or vice versa ?
There is no size standardisation for the heart which may be problematic (apparent heart size is different).
What are some specific kinds of X-ray imaging techniques ?
Mammography
Fluoroscopy
Angiography
What is mammography ?
- Kind of X-ray imaging
- Uses low dose X-ray system designed for detailed images of breasts to detect early breast cancer (no sign of breast disease or diagnose breast disease (with signs of breast disease)
What is fluoroscopy ?
- Kind of X-ray imaging
- X-ray beam passes through body image transmitted to monitor so continuous movement of body part/instrument/agent seen in detail on fluorescent -screen.
- Used when real time examination of patient is necessary
- Uses include positioning of orthopaedic implants in surgery, pacemakers, viewing movement of contrast agents (Barium) etc.
What is an angiography ?
- Kind of X-ray imaging
- Used in examinations of arteries, veins and organs to diagnose blockages
- Uses catheter inserted in vein from groin or arm usually, and contrast agent added to make blood vessels visible.
What do CAT and CT stand for ?
Computerised Axial Tomography and Computed Tomography
What is tomography ?
- Method used to produce images of single tissue plane.
- Tomographic images are produced by motion of x-ray tube and film or by motion of patient to blur image except in a single plane.
What is CT/CAT ?
Radiological imagining using computer processing to generate image of tissue density (in slice as thin as 1 mm).
What is the main difference between X-ray and CT?
CT is cross-sectional (but still a variable of X-ray)
What are the pros of CT Scan ?
- Fast
- Readily Available
- Good imaging of bones, abdomen, and lungs.
What are the cons of CT Scan ?
- High radiation dose (may not want to do it to a child)
- Not good imagining of soft tissues (brain and spinal chord)
What are examples of Nuclear Medicine/Scintigraphy ?
Pet Scan, bone scan, thyroid scan, renal scan (e.g. showing scarring).
What is Nuclear Medicine/Scintigraphy and how does it work ?
The use of gamma radiation to form images following injections of radiopharmaceuticals (such as technetium 99mTc).
Gamma rays emitted from metastable radionuclides detected by gamma camera which converts absorbed energy of radiation to electrical signal. Signal then analysed and displayed by computer.
