Research ArticleIMAGING

Patient Weight–Based Acquisition Protocols to Optimize18F-FDG PET/CT Image Quality

Akio Nagaki, Masahisa Onoguchi and Norikazu Matsutomo
Journal of Nuclear Medicine Technology June 2011, 39 (2) 72-76; DOI: https://doi.org/10.2967/jnmt.110.081661

Article Figures & Data

Figures

  • FIGURE 1.
    FIGURE 1.

     Plots of true coincidence rate (A), random coincidence rate (B), and NECR (C) vs. injected dose per patient weight for 76 patient scans. True coincidence rate, random coincidence rate, and NECR significantly increased with increasing injected dose. NECR maximized at 10.11 MB/kg.

  • FIGURE 2.
    FIGURE 2.

     Plots of COV vs. injected dose per patient weight. At lower injected dose, COV of PET images shows steep decline.

  • FIGURE 3.
    FIGURE 3.

     Image quality of approximately same injected dose of 18F-FDG in patients of different body weights. PET images of underweight patients had lower COV and excellent quality. In contrast, PET images of overweight patients were noisy and of poor quality.

  • FIGURE 4.
    FIGURE 4.

     True coincidence rate (A), COV of PET images (B), and random fraction (C) for 4 patient-weight groups. Except for group 3 vs. group 4 (P < 0.01), true coincidence rate differed significantly among groups. COV of the 4 groups differed significantly for all pairs (P < 0.01). Average random fraction was approximately 35% in all groups (P = not statistically significant). RF = random fraction.

  • FIGURE 5.
    FIGURE 5.

     Follow-up images of 102-kg patient with lymphoma, injected with 388.7 MBq (A) and 254.1 MBq (B) of 18F-FDG. Because optimal protocols were regulated by acquisition time (A, 120 s/bed position; B, 190 s/bed position), COVs of PET images were nearly identical (A, 18.5%; B, 18.8%).

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