Go Akamatsu1, Katsuhiko Mitsumoto2, Takafumi Taniguchi3, Yuji Tsutsui4, Shingo Baba5, Masayuki Sasaki6. 1. Division of Medical Quantum Science, Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; Institute of Biomedical Research and Innovation, 2-2, Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan. Electronic address: golilin5@gmail.com. 2. Division of Medical Quantum Science, Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. Electronic address: kamitsumo@gmail.com. 3. Division of Medical Quantum Science, Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. Electronic address: bock.0517.tt@gmail.com. 4. Department of Medical Technology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. Electronic address: yuji1006@med.kyushu-u.ac.jp. 5. Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. Electronic address: sbaba127@radiol.med.kyushu-u.ac.jp. 6. Division of Medical Quantum Science, Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. Electronic address: msasaki@hs.med.kyushu-u.ac.jp.
Abstract
PURPOSE: The purpose of this study was to investigate the effects of point-spread function (PSF) and time-of-flight (TOF) on the standardized uptake value (SUV) of lymph node metastasis in FDG-PET/CT. MATERIALS AND METHODS: This study evaluated 41 lymph node metastases in 15 patients who had undergone (18)F-FDG PET/CT. The lesion diameters were 2.5 cm or less. The mean short-axis diameter of the lymph nodes was 10.5 ± 3.7 mm (range 4.6-22.8mm). The PET data were reconstructed with baseline OSEM algorithm, with OSEM+PSF, with OSEM+TOF and with OSEM+PSF+TOF. A semi-quantitative analysis was performed using the maximum and mean SUV of lymph node metastases (SUVmax and SUVmean) and mean SUV of normal lung tissue (SUVlung). We also evaluated image quality using the signal-to-noise ratio in the liver (SNRliver). RESULTS: Both PSF and TOF increased the SUV of lymph node metastases. The combination of PSF and TOF increased the SUVmax by 43.3% and the SUVmean by 31.6% compared with conventional OSEM. By contrast, the SUVlung was not influenced by PSF and TOF. TOF significantly improved the SNRliver. CONCLUSION: PSF and TOF both increased the SUV of lymph node metastases. Although PSF and TOF are considered to improve small-lesion detectability, it is important to be aware that PSF and TOF influence the accuracy of quantitative measurements.
PURPOSE: The purpose of this study was to investigate the effects of point-spread function (PSF) and time-of-flight (TOF) on the standardized uptake value (SUV) of lymph node metastasis in FDG-PET/CT. MATERIALS AND METHODS: This study evaluated 41 lymph node metastases in 15 patients who had undergone (18)F-FDG PET/CT. The lesion diameters were 2.5 cm or less. The mean short-axis diameter of the lymph nodes was 10.5 ± 3.7 mm (range 4.6-22.8mm). The PET data were reconstructed with baseline OSEM algorithm, with OSEM+PSF, with OSEM+TOF and with OSEM+PSF+TOF. A semi-quantitative analysis was performed using the maximum and mean SUV of lymph node metastases (SUVmax and SUVmean) and mean SUV of normal lung tissue (SUVlung). We also evaluated image quality using the signal-to-noise ratio in the liver (SNRliver). RESULTS: Both PSF and TOF increased the SUV of lymph node metastases. The combination of PSF and TOF increased the SUVmax by 43.3% and the SUVmean by 31.6% compared with conventional OSEM. By contrast, the SUVlung was not influenced by PSF and TOF. TOF significantly improved the SNRliver. CONCLUSION: PSF and TOF both increased the SUV of lymph node metastases. Although PSF and TOF are considered to improve small-lesion detectability, it is important to be aware that PSF and TOF influence the accuracy of quantitative measurements.
Authors: Georg Kuhnert; Ronald Boellaard; Sergej Sterzer; Deniz Kahraman; Matthias Scheffler; Jürgen Wolf; Markus Dietlein; Alexander Drzezga; Carsten Kobe Journal: Eur J Nucl Med Mol Imaging Date: 2015-08-18 Impact factor: 9.236
Authors: Julian M M Rogasch; Ingo G Steffen; Sandra Riedel; Ivayla Apostolova; Heinz Wertzel; H Jost Achenbach; Ferdinand L G A Steinkrüger; Thomas Kalinski; Meinald Schultz; Jens Schreiber; Holger Amthauer; Christian Furth Journal: Eur Radiol Date: 2015-11-11 Impact factor: 5.315