Table 1.
SPECT and PET imaging set-up for Jaszczak and NEMA phantoms.
Fig 1.
Images obtained by summing 5 transaxial slices of phantom section with uniform concentration of Y-90 (on the left) and corresponding profiles through the centre if each image (on the right). A: non-attenuation corrected image (the shape of the profile is the result of attenuation in the phantom); B: image reconstructed with the original attenuation correction map (the shape of the profile indicates overcorrection of attenuation); C: image reconstructed with the adjusted attenuation correction map (visible improvement in the uniformity of the profile).
Fig 2.
SPECT/CT images of the Jaszczak phantom with different isotope concentrations.
A: Y-90 concentration of 0.1 MBq/ml, B: Y-90 simulated concentration of 1 MBq/ml. From left to right CT image, SPECT image and fusion of the two.
Fig 3.
PET/CT images of the Jaszczak phantom with different isotope concentrations.
A: Y-90 concentration of 0.1 MBq/ml, B: Y-90 simulated concentration of 1 MBq/ml. From left to right CT image, PET image and fusion of the two.
Table 2.
Number of visible cold foci in all analysed Jaszczak phantom images.
Fig 4.
CNR values of all cold foci in SPECT (A) and PET (B) imaging. Images numbered as in Table 2. In A the lines depict the border values of visibility of the region based on Rose criterion (3.7; 4; 4.3); in B the lines depict the border values of visibility of the region based on Rose criterion (2.5; 3; 3.5).
Fig 5.
SPECT/CT images of the NEMA phantom without (A) and with Y-90 in the background (B). From left to right CT image, SPECT image and fusion of the two.
Fig 6.
PET/CT images of the NEMA phantom without (A) and with Y-90 in the background (B). From left to right CT image, PET image and fusion of the two.
Fig 7.
CNR values of hot foci in the NEMA phantom calculated from SPECT (A) and PET (B) images. In A the red marker for the image with Y-90 activity in the background represents the smallest sphere (CNR = 3). All but one foci were clearly visible, as confirmed by CNR values exceeding the threshold of 4 set by the Rose criterion. In B all foci were clearly visible, as confirmed by CNR values exceeding the threshold of 5 set by the Rose criterion.
Table 3.
Inter-observer agreement analysis results for Jaszczak phantom studies.