Accuracy of 177Lu activity quantification in SPECT imaging: a phantom study

Table 3 Details of planar and tomographic acquisitions performed to determine the CNF for ¹⁷⁷Lu

	Mode (phantom)	Fig. 5 data	Source info	Acquisition parameters
A	Planar^a (point source)	Planar methods 1 and 2	Activity 11.7 MBq Volume 0.5 ml Scan duration = 10 min	Collimator MELP PW [187.2–228.8] keV LSW [153.0–187.0] keV USW [229.5–280.2] keV
B	Tomographic^b (uniformly hot cylinder)	SPECT cylinder	Total activity 659.6 MBq Volume 6500 ml #Projections = 96 Time/projection = 10s
C	Tomographic (6 bottles in air)	SPECT air	Total activity 233.4 MBq Vol bottles [17–199.5] ml #Projections = 90 Time/projection = 20s
D	Tomographic (6 spheres in warm water)	SPECT HW1	Total activity 489.1 MBq Vol bottles [17–199.5] ml #Projections = 90 Time/projection = 30s
E	Tomographic (6 spheres in warm water)	SPECT HW2	Total activity 681.3 MBq Vol bottles [17–199.5] ml #Projections = 90 Time/projection = 30s

^aThe camera sensitivity does not depend on the source-collimator distance although increase in recorded counts may occur due to septal penetration if the sources are placed very close to the collimator. To minimize this effect, in this study the point sources were placed at 30 cm from the collimator surface
^bUniform cylinder was scanned at the L’Hôtel-Dieu de Québec site of the CHU de Québec–Université Laval center (Quebec City, Canada) and dual energy window was performed for scatter correction on this phantom