Dose Course 2018_Flipping book

Possible solutions

• Avoid bringing beams in through the implant if possible (possible with eg single hip implants) • Use avoidance sectors (single hip) or constraints (bilateral hip) • Assign artifacts a bulk density of water or tissue • Use (saturated) CT number for metal implants • Use extended CT number (or manufacturer data) to assign ‘actual’ metal

Co-Cr-Mo alloy

titanium steel

Fe 65% Cr 18%

Co 60% Cr 30% Mo 5%

Ti 90% Al 6% Va 4%

atomic composition

Ni 12 Mo 3

ρ [g/cm 3 ] relative electron

7.9

4.3

8.1

6.8

3.6

6.7