3
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Impact of penalizing factor in a block-sequential regularized expectation maximization reconstruction algorithm for 18F-fluorocholine PET-CT regarding image quality and interpretation

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Background

          Recently, the block-sequential regularized expectation maximization (BSREM) reconstruction algorithm was commercially introduced (Q.Clear, GE Healthcare, Milwaukee, WI, USA). However, the combination of noise-penalizing factor (β), acquisition time, and administered activity for optimal image quality has not been established for 18F-fluorocholine (FCH). The aim was to compare image quality and diagnostic performance of different reconstruction protocols for patients with prostate cancer being examined with 18F-FCH on a silicon photomultiplier-based PET-CT. Thirteen patients were included, injected with 4 MBq/kg, and images were acquired after 1 h. Images were reconstructed with frame durations of 1.0, 1.5, and 2.0 min using β of 150, 200, 300, 400, 500, and 550. An ordered subset expectation maximization (OSEM) reconstruction with a frame duration of 2.0 min was used for comparison. Images were quantitatively analyzed regarding standardized uptake values (SUV) in metastatic lymph nodes, local background, and muscle to obtain contrast-to-noise ratios (CNR) as well as the noise level in muscle. Images were analyzed regarding image quality and number of metastatic lymph nodes by two nuclear medicine physicians.

          Results

          The highest median CNR was found for BSREM with a β of 300 and a frame duration of 2.0 min. The OSEM reconstruction had the lowest median CNR. Both the noise level and lesion SUV max decreased with increasing β. For a frame duration of 1.5 min, the median quality score was highest for β 400-500, and for a frame duration of 2.0 min the score was highest for β 300-500. There was no statistically significant difference in the number of suspected lymph node metastases between the different image series for one of the physicians, and for the other physician the number of lymph nodes differed only for one combination of image series.

          Conclusions

          To achieve acceptable image quality at 4 MBq/kg 18F-FCH, we propose using a β of 400-550 with a frame duration of 1.5 min. The lower β should be used if a high CNR is desired and the higher if a low noise level is important.

          Electronic supplementary material

          The online version of this article (10.1186/s40658-019-0242-2) contains supplementary material, which is available to authorized users.

          Related collections

          Most cited references16

          • Record: found
          • Abstract: found
          • Article: not found

          Molecular imaging of cancer with positron emission tomography.

          The imaging of specific molecular targets that are associated with cancer should allow earlier diagnosis and better management of oncology patients. Positron emission tomography (PET) is a highly sensitive non-invasive technology that is ideally suited for pre-clinical and clinical imaging of cancer biology, in contrast to anatomical approaches. By using radiolabelled tracers, which are injected in non-pharmacological doses, three-dimensional images can be reconstructed by a computer to show the concentration and location(s) of the tracer of interest. PET should become increasingly important in cancer imaging in the next decade.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Studies of a Next-Generation Silicon-Photomultiplier-Based Time-of-Flight PET/CT System.

            This article presents system performance studies for the Discovery MI PET/CT system, a new time-of-flight system based on silicon photomultipliers. System performance and clinical imaging were compared between this next-generation system and other commercially available PET/CT and PET/MR systems, as well as between different reconstruction algorithms.Methods:Spatial resolution, sensitivity, noise-equivalent counting rate, scatter fraction, counting rate accuracy, and image quality were characterized with the National Electrical Manufacturers Association NU-2 2012 standards. Energy resolution and coincidence time resolution were measured. Tests were conducted independently on two Discovery MI scanners installed at Stanford University and Uppsala University, and the results were averaged. Back-to-back patient scans were also performed between the Discovery MI, Discovery 690 PET/CT, and SIGNA PET/MR systems. Clinical images were reconstructed using both ordered-subset expectation maximization and Q.Clear (block-sequential regularized expectation maximization with point-spread function modeling) and were examined qualitatively.Results:The averaged full widths at half maximum (FWHMs) of the radial/tangential/axial spatial resolution reconstructed with filtered backprojection at 1, 10, and 20 cm from the system center were, respectively, 4.10/4.19/4.48 mm, 5.47/4.49/6.01 mm, and 7.53/4.90/6.10 mm. The averaged sensitivity was 13.7 cps/kBq at the center of the field of view. The averaged peak noise-equivalent counting rate was 193.4 kcps at 21.9 kBq/mL, with a scatter fraction of 40.6%. The averaged contrast recovery coefficients for the image-quality phantom were 53.7, 64.0, 73.1, 82.7, 86.8, and 90.7 for the 10-, 13-, 17-, 22-, 28-, and 37-mm-diameter spheres, respectively. The average photopeak energy resolution was 9.40% FWHM, and the average coincidence time resolution was 375.4 ps FWHM. Clinical image comparisons between the PET/CT systems demonstrated the high quality of the Discovery MI. Comparisons between the Discovery MI and SIGNA showed a similar spatial resolution and overall imaging performance. Lastly, the results indicated significantly enhanced image quality and contrast-to-noise performance for Q.Clear, compared with ordered-subset expectation maximization.Conclusion:Excellent performance was achieved with the Discovery MI, including 375 ps FWHM coincidence time resolution and sensitivity of 14 cps/kBq. Comparisons between reconstruction algorithms and other multimodal silicon photomultiplier and non-silicon photomultiplier PET detector system designs indicated that performance can be substantially enhanced with this next-generation system.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Phantom and Clinical Evaluation of the Bayesian Penalized Likelihood Reconstruction Algorithm Q.Clear on an LYSO PET/CT System.

              Q.Clear, a Bayesian penalized-likelihood reconstruction algorithm for PET, was recently introduced by GE Healthcare on their PET scanners to improve clinical image quality and quantification. In this work, we determined the optimum penalization factor (beta) for clinical use of Q.Clear and compared Q.Clear with standard PET reconstructions.
                Bookmark

                Author and article information

                Contributors
                +46 40 33 87 24 , mimmi.bjoersdorff@med.lu.se
                jenny.oddstig@skane.se
                Nina.Karindotter-Borgendahl@skane.se
                Helen.Almquist@skane.se
                Sophia.zackrisson@med.lu.se
                david.minarik@med.lu.se
                elin.tragardh@med.lu.se
                Journal
                EJNMMI Phys
                EJNMMI Phys
                EJNMMI Physics
                Springer International Publishing (Cham )
                2197-7364
                21 March 2019
                21 March 2019
                December 2019
                : 6
                : 5
                Affiliations
                [1 ]Clinical Physiology and Nuclear Medicine, Skåne University Hospital and Lund University, Malmö, Sweden
                [2 ]Radiation Physics, Skåne University Hospital and Lund University, Carl Bertil Laurells gata 9, SE-205 02 Malmö, Sweden
                [3 ]Medical Radiology, Skåne University Hospital and Lund University, Carl Bertil Laurells gata 9, SE-205 02 Malmö, Sweden
                [4 ]ISNI 0000 0001 0930 2361, GRID grid.4514.4, Wallenberg Center for Molecular Medicine, , Lund University, ; Lund, Sweden
                Author information
                http://orcid.org/0000-0001-8715-507X
                Article
                242
                10.1186/s40658-019-0242-2
                6428870
                30900064
                05b49e5f-bdcd-4347-9907-d34453706e2a
                © The Author(s). 2019

                Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

                History
                : 16 August 2018
                : 5 March 2019
                Funding
                Funded by: FundRef http://dx.doi.org/10.13039/501100004063, Knut och Alice Wallenbergs Stiftelse;
                Award ID: -
                Award Recipient :
                Categories
                Original Research
                Custom metadata
                © The Author(s) 2019

                image quality,oncology,18f-fch,protocol optimization,q.clear

                Comments

                Comment on this article