U1 P4

secondary factors that influence RE (9)

- focal spot size
- anode heel
- radiographic distances (SID/OID)
- Grid
- Beam restriction (collimation)
- Generator output (single phase/third phase)
- Filtration
- Image acquisition system (film screen/CR/DR) - Patient factors

focal spot

area on anode where electrons strike (source of x-ray production)

focal spot blooming

damage to the filament; occurs when focal spot size increase with increasing mA, low kVp

Focal Spot Size (FSS) affects

↑ FSS ↓ spatial resolution; ↓ FSS ↑ spatial resolution

anode heel effect

x-ray intensity is > on cathode side & < on anode side

OID (air-gap) affects

radiation intensity & amount of scatter radiation, reaching IR

↑OID ↓ what?

↓ amount of scatter reaching IR

↑grid ratio ↓ what?

↓RE

beam restriction/collimation on RE:
selection of a small field size
selection of a large field size

↑collimation ↓RE
↓collimation ↑RE

generation configuration/power supply on RE:
= mAs & kVp will produce
↑ generator phase & pulse

higher quantity & quality radiation
↑ RE

filtration on RE:

filtration serves to reduce patient skin entrance dose by removing low energy photons from the x-ray beam (should be QCd)

↑ filtration ↓ what?

receptor exposure

Filtration absorbs lower-energy x-ray photons
before?

they reach the patient

Filtration ⬆ the percentage of higher energy x-rays remaining in the beam meaning

increase average energy of the primary beam

What is the greatest variable the radiographer faces in the production of an image?

the patient

major tissue groups listed from < tissue density to > tissue density

Air (lungs, sinuses, intestinal
Fat (tissue)
Muscle (muscle, glands, non-fatty tissue)
Bone/Teeth

other factors that influence radiograph

part thickness, body habitus, age, contrast agents, pathology (additive or destructive), casts/splint