Fig. 4
Influence of different background activity values on TBRmax and BTV values. a An example of a simple 2D-ROI assessment with measured background SUV values between 1.17–1.50: the resulting TBRmax ranges between 3.10 and 4.01 (ΔTBRmax, 0.91; %ΔTBR, 29%), the BTV delineated with the calculated lowest threshold of SUV 1.87 is 45.89 ml, while BTV using the threshold with the highest background SUV (threshold SUV 2.40) results in a BTV with 9.91 ml only (ΔBTV, 35.98 ml; %ΔBTV, 78%). b The guided VOI assessment with a maximal background SUV range of 0.83–0.87 results in a small TBR range of 2.99–3.13 (ΔTBRmax, 0.14; %ΔTBRmax, 4%) and a BTV range of 20.53–22.63 ml (ΔBTV, 2.10 ml; %ΔBTV, 9%)