Article Figures & Data
Figures
- FIGURE 1.
Illustrations of single slice (left) and average of multiple slices (right) for mini-Derenzo phantom at center of FOV in 2 orientations: with rod perpendicular to axial plane (initially filled with 16.3 MBq of 18F-FDG and imaged for 10 min) and in coronal plane (same phantom imaged for 20 min with initial activity of 8.6 MBq). Images were reconstructed using PSF-based TOF OSEM algorithm with 7 iterations, 10 subsets, voxel size of 0.6 × 0.6 × 0.8 mm3, and 1 mm FWHM gaussian postreconstruction filter. Gray scale was adjusted to cover range from minimum value to 40% of maximum value for each respective image.
- FIGURE 2.
Axial sensitivity profiles measured with 70-cm line source positioned at transaxial center and 10 cm off-center. Sinogram slice thickness was 1.46 mm.
- FIGURE 3.
(A) Results for true, scatter, and random count rates and NECR as function of activity concentration. (B) Scatter fraction, TOF resolution, energy resolution, and accuracy measured as function of activity concentration. NECR curve was plotted using double y-axes. Vertical dashed lines denote peak NECR.
- FIGURE 4.
Four transverse image slices of Hoffman brain phantom. Phantom was filled with 48.8 MBq of 18F-FDG and scanned for 10 min. Gray scale was scaled to same range from minimum to maximum for each slice. Bottom left slice was used to calculate radioactivity concentration ratio and contrast recovery.
- FIGURE 5.
Images from 56-y-old female patient (body mass index, 22.6) diagnosed with plantar squamous cell carcinoma; injected activity was 314 MBq, and uptake time was 69 min. Images were reconstructed using PSF-based TOF OSEM algorithm with 3 iterations, 10 subsets, 2 mm FWHM gaussian postreconstruction filter, and voxel dimensions of 1.8 × 1.8 × 2.14 mm3. (A) Sequential maximum-intensity projections and transaxial image slices with acquisition times of 14, 10.5, 7, and 3.5 min from left to right, corresponding to 2, 1.5, 1, and 0.5 min/bed, respectively. Liver coefficients of variability were 12.8%, 15.3%, 19.7%, and 25.6% from left to right, respectively. (B) Comparison of TOF (upper row) and non-TOF (lower row) images; from left to right, images represent CT, PET, and PET/CT fusion images, respectively. (C) Zoomed-in images from B, highlighting high resolution of closely located pulmonary nodules in TOF images. Images from left to right represent CT, TOF fusion, and non-TOF fusion images, respectively. For fusion images in C, lower window of intensity scale bar was set to SUV of 1.
- FIGURE 6.
Neuroimaging of 63-y-old patient (body mass index, 18.2) who had cognitive impairment with 303 MBq of 18F-FDG PET. Images were acquired at 52 min after injection with single-bed acquisition lasting 10 min. TOF and non-TOF images were reconstructed using PSF-based TOF OSEM algorithm with 7 iterations, 10 subsets, 1 mm FWHM gaussian postreconstruction filter, and voxel size of 0.6 × 0.6 × 0.8 mm3. (A) TOF images compared with non-TOF images, showing better recovery of cold regions in ventricles, gyri, sulci, and nucleus with TOF. (B) Multiple transaxial planes of TOF images. (C) Sagittal view showcasing single-bed axial FOV (35.1 cm) of uMI Panorama. (D) Zoomed-in comparison of TOF with non-TOF images from B, revealing enhanced clarity of insula gyri, nuclei, and spinal cords in TOF images. Grayscale consistency was maintained across PET images in A–D. DN = dentate nucleus; FN = fastigial nucleus; IC = inferior colliculus; LGB = lateral geniculate body; MB = mammillary body; MGB = medial geniculate body; RN = red nucleus; SC = superior colliculus; STN = subthalamic nucleus.
- FIGURE 7.
72-y-old male patient (body mass index, 18.6) presenting with non–small cell lung cancer for staging. Patient received injection of 203 MBq of 18F-FDG. Four-bed (2 min/bed, 45% bed overlap) whole-body scan was performed at 65 min after injection. Image was reconstructed using PSF-based TOF OSEM algorithm with 3 iterations, 10 subsets, 2 mm FWHM gaussian postreconstruction filter, and voxel size of 1.8 × 1.8 × 2.14 mm3. (A) Primary lesion (green arrowhead) and suspected metastatic lesion (red arrowhead). (B) CT transverse image reveals nodules of approximately 4-mm diameter in both lungs, corresponding to abnormal uptake on PET image. Long-axis measurement of 6.1 mm corresponds to suspected lesion highlighted by red arrowhead in A. Numeric values indicate lesion SUVmean. (C) Subcentimeter cold region suggestive of hepatic cyst, consistent with hypodense appearance on CT scan.
Tables
Location Position (cm) FWHM (mm) Tangential Radial Axial Center axial FOV 1 3.02 2.72 2.74 10 3.21 3.19 2.89 20 3.57 4.80 3.10 1/8 axial FOV 1 3.03 2.73 2.80 10 3.06 3.22 2.95 20 3.53 4.91 3.08 Average of 1/2 and 1/8 1 3.03 2.73 2.77 10 3.14 3.2 2.92 20 3.55 4.85 3.09 - TABLE 2.
Mean, Maximum, and Minimum Percentages of Contrast Recovery, Background Variability, and Lung Residual for 4.0:1 Sphere-to-Background Ratio*
Parameter Percentage for sphere diameter of: Percentage for lung residual 10 mm 13 mm 17 mm 22 mm 28 mm 37 mm Contrast recovery Mean 63.2 69.6 76.7 80.7 84.3 88.4 1.2 Maximum 64.8 70.4 77.5 81.3 85.2 88.9 1.3 Minimum 61.1 68.9 75.6 79.9 83.7 88.1 1.1 Background variability Mean 4.2 3.3 2.4 1.7 1.4 1.1 1.3 Maximum 4.9 3.7 2.6 1.8 1.4 1.2 1.4 Minimum 3.6 2.9 2.1 1.5 1.3 1.0 1.2 ↵* Based on 3 sequential measurements of NEMA image quality phantom.
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