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@ARTICLE{Li:943359,
      author       = {Li, Chong and Scheins, Jürgen and Tellmann, Lutz and Issa,
                      Ahlam and Wei, Long and Shah, N Jon and Lerche, Christoph},
      title        = {{F}ast 3{D} kernel computation method for positron range
                      correction in {PET}},
      journal      = {Physics in medicine and biology},
      volume       = {68},
      number       = {2},
      issn         = {0031-9155},
      address      = {Bristol},
      publisher    = {IOP Publ.},
      reportid     = {FZJ-2023-00958},
      pages        = {025004 -},
      year         = {2023},
      abstract     = {Objective. The positron range is a fundamental,
                      detector-independent physical limitation to spatial
                      resolution in positron emission tomography (PET) as it
                      causes a significant blurring of underlying activity
                      distribution in the reconstructed images. A major challenge
                      for positron range correction methods is to provide accurate
                      range kernels that inherently incorporate the generally
                      inhomogeneous stopping power, especially at tissue
                      boundaries. In this work, we propose a novel approach to
                      generate accurate three-dimensional (3D) blurring kernels
                      both in homogenous and heterogeneous media to improve PET
                      spatial resolution. Approach. In the proposed approach,
                      positron energy deposition was approximately tracked along
                      straight paths, depending on the positron stopping power of
                      the underlying material. The positron stopping power was
                      derived from the attenuation coefficient of 511 keV gamma
                      photons according to the available PET attenuation maps.
                      Thus, the history of energy deposition is taken into account
                      within the range of kernels. Special emphasis was placed on
                      facilitating the very fast computation of the positron
                      annihilation probability in each voxel. Results. Positron
                      path distributions of 18F in low-density polyurethane were
                      in high agreement with Geant4 simulation at an annihilation
                      probability larger than 10−2 ∼ 10−3 of the maximum
                      annihilation probability. The Geant4 simulation was further
                      validated with measured 18F depth profiles in these
                      polyurethane phantoms. The tissue boundary of water with
                      cortical bone and lung was correctly modeled. Residual
                      artifacts from the numerical computations were in the range
                      of $1\%.$ The calculated annihilation probability in voxels
                      shows an overall difference of less than $20\%$ compared to
                      the Geant4 simulation. Significance. The proposed method is
                      expected to significantly improve spatial resolution for
                      non-standard isotopes by providing sufficiently accurate
                      range kernels, even in the case of significant tissue
                      inhomogeneities.},
      cin          = {INM-4 / INM-11 / JARA-BRAIN},
      ddc          = {530},
      cid          = {I:(DE-Juel1)INM-4-20090406 / I:(DE-Juel1)INM-11-20170113 /
                      $I:(DE-82)080010_20140620$},
      pnm          = {5253 - Neuroimaging (POF4-525) / DFG project 491111487 -
                      Open-Access-Publikationskosten / 2022 - 2024 /
                      Forschungszentrum Jülich (OAPKFZJ) (491111487)},
      pid          = {G:(DE-HGF)POF4-5253 / G:(GEPRIS)491111487},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {36595256},
      UT           = {WOS:000911421500001},
      doi          = {10.1088/1361-6560/acaa84},
      url          = {https://juser.fz-juelich.de/record/943359},
}