Title:Performance of the Iterative OSEM and HYPER Algorithm for Total-body PET
at SUVmax with a Low 18F-FDG Activity, a Short Acquisition Time and Small
Lesions
Volume: 20
Author(s): Keyu Zan, Yanhua Duan*, Minjie Zhao, Hui Li, Xiao Cui, Leiying Chai and Zhaoping Cheng
Affiliation:
- Department of Nuclear Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital,
Jinan, China
Keywords:
Positron-emission tomography, Reconstruction, Image quality, NEMA, Acquisition time, Injection activity. Article
Abstract:
Objective:
The primary objective of this comparative investigation was to examine the qualitative attributes of image reconstructions utilizing two distinct
algorithms, namely OSEM and HYPER Iterative, in total-body 18F- FDG PET/CT under various acquisition durations and injection activities.
Methods:
An initial assessment was executed using a NEMA phantom to compare image quality engendered by OSEM and HYPER Iterative algorithms.
Parameters such as BV, COV, and CRC were meticulously evaluated. Subsequently, a prospective cohort study was conducted on 50 patients,
employing both reconstruction algorithms. The study was compartmentalized into distinct acquisition time and dosage groups. Lesions were
further categorized into three size-based groups. Quantifiable metrics including SD of noise, SUVmax, SNR, and TBR were computed. Additionally,
the differences in values, namely ΔSUVmax, ΔTBR, %ΔSUVmax, %ΔSD, and %ΔSNR, between OSEM and HYPER Iterative algorithms were also
calculated.
Results:
The HYPER Iterative algorithm showed reduced BV and COV compared to OSEM in the phantom study, with constant acquisition time. In the
clinical study, lesion SUVmax, TBR, and SNR were significantly elevated in images reconstructed using the HYPER Iterative algorithm in
comparison to those generated by OSEM (p < 0.001). Furthermore, an amplified increase in SUVmax was predominantly discernible in lesions with
dimensions less than 10 mm. Metrics such as %ΔSNR and %ΔSD in HYPER Iterative exhibited improvements correlating with reduced
acquisition times and dosages, wherein a more pronounced degree of enhancement was observable in both ΔSUVmax and ΔTBR.
Conclusion:
The HYPER Iterative algorithm significantly improves SUVmax and reduces noise level, with particular efficacy in lesions measuring ≤ 10 mm and
under conditions of abbreviated acquisition times and lower dosages.
