Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

1 Publication
Improving the quantification accuracy of a PET/CT-scanner with pixelated large area detector
Nemer, U.; Maus, J.ORC; Schramm, G.; Meyer, P. T.; Hennig, J.; Mix, M.
One of the main benefits of PET/CT imaging is its ability for absolute quantification. Calibration according to the manufacturer‘s procedure specifies an accuracy of about 10%, whereas especially in dynamic clinical studies a higher quantification accuracy is desired. Therefore a more accurate calibration is needed. At the Gemini TF, a scanner with pixelated large-area LYSO detectors, there are differences in the measurement set-up between calibration and clinical acquisition. This study intends to evaluate the influence of those differences on the calibration with the aim to increase the accuracy of quantification. The major difference herein is the acquisition format, as calibration is performed in histogram-mode (HM-Cal) and clinical acquisition in list-mode format. Using the list-mode format for the calibration (LM-Cal), increases the activity recovery coefficient for the histogram-based acquisition from 0.93±0.08 up to 1.00±0.03. This is however only valid for the calibration set-up but not for clinical situations. Considering more realistic situations like lesions outside the centre of the field of view (FOV) or additional random events coming from highly accumulating regions outside the FOV (like bladder or brain), a different calibration can be found (ALL-Cal). In the evaluation of clinical oncological datasets with low count rates, a significant improvement of the reconstructed mean activity concentration in the bladder (compared to measured urine samples) up to 4% (LM-Cal) was achieved. For very high count rates the normalization of the scanner has to be adapted to improve the quantification accuracy as well.
Keywords: Calibration, Image reconstruction, Phantoms, Table lookup, Positron emission tomography, Bladder, Detectors
  • Contribution to proceedings
    2015 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 31.10.-07.11.2015, San Diego, USA
    Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2015 IEEE, USA: IEEE, 978-1-4673-9862-6
    DOI: 10.1109/NSSMIC.2015.7582097

Publ.-Id: 24864 - Permalink