Figure 1.
The proposed panel-PET scanner for region-of-interest imaging.
The scanner can adjust its position according to different target ROIs.
Figure 2.
Event discrimination in data acquisition.
indicates the arrival time difference of two photons,
is the speed of light,
is the distance between the annihilation position and the midpoint of line-of-response.
Figure 3.
Measurable time differences distribution in conventional (a) and region-of-interest imaging (b).
The distribution was assumed as a Gaussian function with full width at half maximum determined by the system timing resolution.
Figure 4.
Phantom images with the dotted rectangles as imaging region-of-interest.
(a) The NEMA-IQ phantom is about cm
in size, including four hot lesions (10 mm, 13 mm, 17 mm and 22 mm in diameter) and two cold lesions (28 mm and 37 mm in diameter). The region-of-interest size is
cm
. (b) The Zubal abdomen phantom is about
cm
in size. The region-of-interest size is
cm
.
Figure 5.
Reconstructed image of the NEMA-IQ phantom obtained by windowed list-mode ordered subset expectation maximization method.
(a) The initial reconstructed image of the NEMA-IQ phantom. (b) The reconstructed image after the region-of-interest is cropped out. (c) The reconstructed image obtained by conventional list-mode OSEM method. Note that only the structures inside the ROI are displayed.
Figure 6.
Sampled intensity profiles of the reconstructed image shown in Figure 5.
The sample lines in (a) show the locations of the profiles.
Figure 7.
Reconstructed images of NEMA-IQ phantom obtained from TOF-PET data with different timing resolutions.
Note that only the structures inside the ROI are displayed.
Figure 8.
Sampled intensity profiles for NEMA-IQ phantom obtained from TOF-PET data with different TRs.
The profiles were obtained from the reconstructed images shown in Figure 7.
Figure 9.
Reconstructed images of Zubal abdomen phantom obtained from TOF-PET data with different timing resolutions.
The circle shows the low uptake lesion inside the liver. Note that only the structures inside the ROI are displayed.
Figure 10.
Contrast recovery coefficients versus iteration number for the TOF-PET data with different timing resolutions.
To avoid misleading impacts introduced by artifacts and distortions on contrast recovery coefficient values, only image results for 100–400 ps full width at half maximum TOF-PET data were analyzed here.