Week 1 Flashcards
What is radiology?
The branch of medicine responsible for the use of radiant energy, radiant substances, and non ionizing studies
What are the radiant substances used in radiology?
- Radioactive isotopes
* Ionizing radiation
What are the non ionizing studies used in radiology?
- Sonography
* MRI
____ is the most common modality for bone and joint disorders
Conventional radiography is the most common modality for bone and joint disorders
What are the advantages of conventional radiography?
- First order diagnostic study
- Little risk
- Time effective
- Cost effective
How does a standard/conventional radiographs produce images?
Images are produced on a sensitive plate or film using a dispersion of X-rays, gamma rays or similar radiation.
Where does radiation pass through a person?
Radiation passes through patient where there is attenuation/changed or blocked
What does the amount of attenuation for a pt depend on during radiology?
Dependent on density of tissue
What happens with the remnant radiation during a standard radiograph?
Remnant radiation is incepted by receptor and creates visual image
What are the effects of radiation on the body?
- Neural atoms gains or loses an electron
- Disrupts composition of matter
- Disrupts life process
What is air kerma?
The amount of radiation that is absorbed in the absence of scatter/ by just the air
What is a dose-area product?
The integral of air kerma for an entire x-ray beam, based on the amount of radiation emitted
What is an absorbed dose/CT dose?
Dose of radiation from the primary beam that is emitted plus scatter from surrounding slices and is expressed in units of Gray-Gy.
(Energy that is deposited in patient)
What is an equivalent dose?
The absorbed dose adjusted by weighting factor of type of radiation and is expressed in units of Sieverts-Sv
Absorbed dose that is adjusted for harmful effects
What is the weighting factor of CTs and Xrays?
1 Sv
What is an effective dose?
An adjustment of equivalent dose based on tissue susceptibility to ionizing radiation, also expressed in (Sv)
Equivalent dose that is adjusted for the harm that it causes to different tissues
What part of the body must we be more careful of during radiography and why?
The abdominal region, d/t the organ’s susceptibility to absorb radiation
What is the yearly limit of radiation for nuclear workers?
20 mSv
What is the average dose of radiation from a full body CT scan?
10 mSv
What is the yearly dose of radiation that an average airline crew gets?
9 mSv
What is the amount of radiation from a single mammogram?
3 mSv
What is the average yearly background radiation dose in the UK?
2 mSv
What is the amount of radiation in a single chest xray?
0.1 mSv
At what level of radiation is the higher risk of cancer noticeable?
100 mSv
___ is responsible for the images we see in a radiograph
Radiodensity is responsible for the images we see in a radiograph
What is radiodensity?
Physical qualities of an object that determine how much radiation it absorbs
What is radiodensity based on?
- Composition: effective anatomic number or volume density
* Thickness
The greater the atomic number, volume density and/or thickness, the ____ the radiodensity. What does that mean?
The greater the atomic number, volume density and/or thickness, the greater the radiodensity. A greater radiodensity = less radiation getting through
What are the characteristics of a radiolucent image?
- Mostly associated with air
- Minimal absorption
- Presents in a black color
What are the characteristics of a radioopaque image?
- Mostly associated with heavy metal
- High radiodensity
- Presents in a white/clear color
At least how many images should be available when looking at conventional radiographs?
Always at least 2
What is the quality of a conventional radiograph based on?
- Density: Blackening of image
- Contrast: Difference among adjacent densities
- Detail: Geometric sharpness or accuracy
- Distortion: Difference between actual object and its recorded image. size and shape
What is the sensitivity and specificity of wrist fractures and radiographs?
- Sensitivity= 0.58
* Specificity= 0.99
What is the sensitivity and specificity of lumbar fractures and radiographs?
- Sensitivity= 0.73
* Specificity= 0.99
What is the sensitivity and specificity of bony metastasis and radiographs?
- Sensitivity= 0.6
* Specificity= 0.99
What is the sensitivity and specificity of Partial RTC tear and a MRI?
- Sensitivity= 0.67-0.83
* Specificity= 0.99
What is the sensitivity and specificity of stress fractures and radiographs?
- Sensitivity= 0.12-0.56
* Specificity=0.88-0.96
