Improving SPECT image using CT information

I-131 radioimmunotherapy is a novel treatment for Non-Hodgkin lymphoma (NHL) that combines a traditional radiation therapy and a new monoclonal antibody. Even though it has shown remarkable treatment results for NHL, it is still challenging to determine the right amount of dose for each patient so that most cancer cells are killed while most normal cells are preserved. Single Photon Emission Computed Tomography (SPECT) imaging can be used to determine that. However, SPECT has limited spatial resolution.

A high resolution CT image always has to be acquired in SPECT scan. We developed methods to improve the SPECT quantitation using CT side information. We proposed a few non-local means (NLM) based filters and regularizers that incorporate CT information and showed improved quantitation. The figure on the right shows that compared to the unregularized OSEM reconstruction (top left), NLM filtering reduced the noise (top right) and NLM regularizer improved the quantitation result further (bottom left). Our proposed method using CT side information substantially improved the quality of reconstructed image (bottom right) and quantitation result.

  1. S Y Chun, J A Fessler, Y K Dewaraja, “Post-reconstruction non-local means filtering methods using CT side information for quantitative SPECT,” Physics in Medicine and Biology, 58(17):6225-40, Sep. 2013.
  2. S Y Chun, J A Fessler, Y K Dewaraja, “Non-local means methods using CT side information for I-131 SPECT image reconstruction,” Proc. IEEE Nuc. Sci. Symp. and Med. Imag. Conf., pp. 3362-6, 2012.

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