Radiation Physics Flashcards
Define X-ray beam intensity
Intensity of a beam is equal to number of photons in the x-ray beam
OR
The amount of photon energy passing through a unit area per unit of time
Define X-ray beam quality
The range of photon energies carried by the X-ray beam (also known as the “penetrating power”)
What affects the intensity and quality of the X-ray beam
- Tube voltage
- Tube current
- Exposure time
- Filtration
- Atomic number of target metal
What affect would the size of the tube current have on the intensity and quality of the beam
Intensity = increase (more X-ray photons produced)
Quality = no change
What affect would the distance of the image receptor from the anode target have on the intensity and quality of the X-ray beam
Intensity = decrease (target is further away so radiation is spread over a larger SA)
Quality = no change
What affect would the exposure time have on the intensity and quality of the X-ray beam
Intensity = increase (more X-ray photons produced)
Quality = no change
What affect does the target anode material have on the intensity and quality of the X-ray beam
Intensity = increase/decrease (depending on the material)
Quality = no change
What process produces the majority of photons
Bremsstrahlung
What process produces a minority of photons
Characteristic production
Duties of the referrer
Health care professional entitled to request/refer for medical exposure
(must supply practitioner with sufficient medical data)
Duties of the operator
Responsible for the practical aspect (performs & optimises medical exposure)
Duties of the practitioner
Responsible for justification of exposure
List some of the justifications of exposure
Objectives
Characteristics of individuals
Total potential diagnostic
Benefits
Individual detriment (risks)
Efficiency, benefits & risk of alternative techniques
