Midterm | Control Pt Exposure Flashcards
Process of attenuating low energy xr photons from the spectrum before reaching to the pt
Beam Filtration/ Beam Hardening
XR beam that eventually records the body part onto the IR
Primary beam
The x-rays that exit the tube are (1); they consist of (2), (3), and (4).
- polyenergetic
- low-energy
- medium-energy
- high-energy photons
Photons that cannot penetrate parts of the anatomy and do not contribute to image formation. They contribute only to patient dose
Low-energy photons
Filtration, xr beam quality, and xr quantity/ emission relationship
↑ Filtration = ↑ xr beam quality = ↓ xr quantity/ emission relationship
Types of Filtration
- Added Filtration
- Inherent Filtration
Filtration that is added to the port of the x-ray tube.
Added Filtration
Material primarily used for added filtrations
Aluminum
Added filtration thickness
1-1.5mm Al equivalent
Filtration that is permanently in the path of the x-ray beam.
Inherent filtration
Three components contribute to inherent filtration:
- envelope of the tube
- oil that surrounds the tube
- window in the tube housing
Inherent filtration thickness
0.5-1mm Al equivalent
Sum of the added and inherent filtration
Total filtration
XRTs operating kVp and their equivalent minimum total filtration
<50kVp = 0.5mm of Al
50-70kVp = 1.5mm of Al
>70kVp = 2.5mm of Al
Materials used for filtration & their uses
Cu (29): for high energy radiation
Al (13): for low energy radiation
