Improving the Spatial Alignment in PET/CT Using Amplitude-Based Respiration-Gated PET and Respiration-Triggered CT

Journal of Nuclear Medicine

Dustin R. Osborne¹  Willem Grootjans¹  Antoi P.W. Meeuwis¹  Charlotte S. van der Vos¹  Eric P. Visser¹  Shelley Acuff¹  James J. Hamill¹  Lioe-Fee de Geus-Oei¹ 

关键词: amplitude-based optimal respiratory gating;    lung tumors;    image quantification in PET;    respiration-triggered CT;    spatial alignment;   

DOI  :  10.2967/jnumed.115.163055

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

Respiratory motion during PET can cause inaccuracies in the quantification of radiotracer uptake, which negatively affects PET-guided radiotherapy planning. Quantitative accuracy can be improved by respiratory gating. However, additional miscalculation of standardized uptake value (SUV) in PET images can be caused by inappropriate attenuation correction due to a spatial mismatch between gated PET and CT. In this study, the effect of respiration-triggered CT on the spatial match between CT and amplitude-based respiration-gated PET images is investigated. Methods: 18F-FDG PET/CT was performed in 38 patients. Images were acquired on 2 PET/CT scanners, one without and one with continuous bed motion during PET acquisition. The amplitude limits of the amplitude-based respiration-gated PET were used for the respiration-triggered sequential low-dose CT. Both standard (spiral) and triggered CT scans were used to reconstruct the PET data. Spatial mismatch was quantified using the position difference between the lung–liver boundary in PET and CT images, the distance between PET and CT lung lesions' centroids, and the amount of overlap of lesions indicated by the Jaccard similarity coefficient. Furthermore, the effect of attenuation correction was quantified by measuring SUVs in lung lesions. Results: For triggered CT, the average distance between the lung–liver boundary in PET and CT was significantly reduced (4.5 ± 6.7 mm) when compared with standard CT (9.2 ± 8.1 mm) (P < 0.001). The mean distance between the lesions' centroids in PET and CT images was 6.3 ± 4.0 and 5.6 ± 4.2 mm (P = 0.424), for the standard and triggered CT, respectively. Similarly, the Jaccard similarity coefficient was 0.30 ± 0.21 and 0.32 ± 0.20 (P = 0.609) for standard and triggered CT, respectively. For 6 lesions, there was no overlap of PET and CT when the standard CT was used; compared with the triggered CT, these lesions showed (partial) overlap. The maximum and mean SUV increase of the PET/CT compared with the PET/triggered CT was 5.7% ± 11.2% (P < 0.001) and 6.1% ± 10.2% (P = 0.001), respectively. Conclusion: Amplitude-based respiration-gated PET in combination with respiration-triggered CT resulted in a significantly improved match in the area of the liver dome and a significantly higher SUV for lung lesions. However, lesions in the lungs did not show a consistent improvement in spatial match.

【 授权许可】

Unknown