Comparison of conventional and Si-photomultiplier-based PET systems for image quality and diagnostic performance

• Published in: BMC medical imaging Vol. 19; no. 1; pp. 81 - 9
• Main Authors: Oddstig, Jenny, Leide Svegborn, Sigrid, Almquist, Helen, Bitzén, Ulrika, Garpered, Sabine, Hedeer, Fredrik, Hindorf, Cecilia, Jögi, Jonas, Jönsson, Lena, Minarik, David, Petersson, Richard, Welinder, Annika, Wollmer, Per, Trägårdh, Elin
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 22-10-2019; BioMed Central; BMC
• Subjects: Algorithms; Annan fysik; CAT scans; Clinical Medicine; Comparative analysis; Detection equipment; Diagnostic equipment (Medical); Diagnostic imaging; Digital PET; FDG; Fluorodeoxyglucose F18 - administration & dosage; Fysik; Ghosts; Humans; Image Interpretation, Computer-Assisted - instrumentation; Image quality; Klinisk medicin; Liver; Liver - diagnostic imaging; Medical and Health Sciences; Medical imaging equipment; Medical research; Medicin och hälsovetenskap; Natural Sciences; Naturvetenskap; Oncology; Other Physics Topics; PET-CT; Phantoms, Imaging; Physical Sciences; Positron emission tomography; Positron Emission Tomography Computed Tomography - methods; Radiologi och bildbehandling; Radiology, Nuclear Medicine and Medical Imaging; Signal-To-Noise Ratio; Silicon; Sport utility vehicles; Technology; Testing; Tomography; Whole Body Imaging; Sweden; Image quality; FDG; Oncology; PET-CT; Digital PET
• ISSN: 1471-2342; 1471-2342
• DOI: 10.1186/s12880-019-0377-6

A new generation of positron emission tomography with computed tomography (PET-CT) was recently introduced using silicon (Si) photomultiplier (PM)-based technology. Our aim was to compare the image quality and diagnostic performance of a SiPM-based PET-CT (Discovery MI; GE Healthcare, Milwaukee, WI, USA) with a time-of-flight PET-CT scanner with a conventional PM detector (Gemini TF; Philips Healthcare, Cleveland, OH, USA), including reconstruction algorithms per vendor's recommendations.
Imaging of the National Electrical Manufacturers Association IEC body phantom and 16 patients was carried out using 1.5 min/bed for the Discovery MI PET-CT and 2 min/bed for the Gemini TF PET-CT. Images were analysed for recovery coefficients for the phantom, signal-to-noise ratio in the liver, standardized uptake values (SUV) in lesions, number of lesions and metabolic TNM classifications in patients.
In phantom, the correct (> 90%) activity level was measured for spheres ≥17 mm for Discovery MI, whereas the Gemini TF reached a correct measured activity level for the 37-mm sphere. In patient studies, metabolic TNM classification was worse using images obtained from the Discovery MI compared those obtained from the Gemini TF in 4 of 15 patients. A trend toward more malignant, inflammatory and unclear lesions was found using images acquired with the Discovery MI compared with the Gemini TF, but this was not statistically significant. Lesion-to-blood-pool SUV ratios were significantly higher in images from the Discovery MI compared with the Gemini TF for lesions smaller than 1 cm (p < 0.001), but this was not the case for larger lesions (p = 0.053). The signal-to-noise ratio in the liver was similar between platforms (p = 0.52). Also, shorter acquisition times were possible using the Discovery MI, with preserved signal-to-noise ratio in the liver.
Image quality was better with Discovery MI compared to conventional Gemini TF. Although no gold standard was available, the results indicate that the new PET-CT generation will provide potentially better diagnostic performance.