% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Lustermans:305672,
      author       = {D. Lustermans and G. P. Fonseca and C. Jeukens and V. T.
                      Taasti and K. Parodi and G. Landry$^*$ and F. Verhaegen},
      title        = {{A}ssessing quantitative material characteristics with low
                      dose imaging in photon-counting and dual-energy computed
                      tomography for radiotherapy.},
      journal      = {Physics in medicine and biology},
      volume       = {70},
      number       = {22},
      issn         = {0031-9155},
      address      = {Bristol},
      publisher    = {IOP Publ.},
      reportid     = {DKFZ-2025-02302},
      pages        = {225008},
      year         = {2025},
      abstract     = {Objective.Photon-counting computed tomography (CT) is an
                      advanced imaging technique that detects individual photons
                      by energy, offering spectral imaging. While its application
                      in radiotherapy remains under-explored, photon-counting CT
                      (PCCT) could provide quantitative accuracy, particularly in
                      proton stopping-power ratio (SPR) estimation, while it also
                      potentially enables consistent low-dose imaging. This study
                      evaluates estimation accuracy for relative electron density
                      (RED), effective atomic number (Zeff), and SPR under
                      low-dose conditions. This could be beneficial for repeated
                      imaging in radiotherapy.Approach.A Gammex Advanced Electron
                      Density phantom (Sun Nuclear) was scanned on a PCCT at 120
                      kVp with varying imaging doses (5 mGy (low dose), 20 mGy,
                      and 40 mGy). Virtual monoenergetic images (VMIs) were
                      generated with energies of 40-70 and 150-190 keV (10 keV
                      increments). Performance was compared to dual-energy CT
                      (DECT) acquisition (80/140 kVp) using the SOMATOM Confidence
                      scanner with similar dose levels, and identically VMIs were
                      generated as for PCCT. Mean ± standard deviation (SD) of CT
                      numbers was quantified for tissue-equivalent phantom
                      inserts. Furthermore, the physical quantities, RED,Zeff, and
                      SPR accuracies were determined under high- and low-dose
                      imaging conditions by quantifying the
                      root-mean-squared-error (RMSE).Main results.PCCT generally
                      showed lower CT number SD than DECT, while for both
                      modalities, the SD increased at lower imaging dose. In
                      addition, PCCT retained consistent mean CT numbers
                      (differences up to 15 Hounsfield Unit (HU)), while DECT
                      showed large CT number variations at 5 mGy (up to 1000 HU)
                      in bone compared to higher dose. The accuracy of the
                      physical quantities was independent of the dose for PCCT
                      $(0.7\%-0.9\%$ SPR RMSE), whereas DECT demonstrated larger
                      differences with dose $(1.1\%-4.6\%$ SPR
                      RMSE).Significance.This study demonstrated that PCCT retains
                      quantitative accuracy in low imaging dose conditions,
                      outperforming DECT. This could be valuable for pediatric
                      patients and in repeated imaging to reduce the cumulative
                      dose.},
      keywords     = {Photons / Phantoms, Imaging / Tomography, X-Ray Computed:
                      methods / Tomography, X-Ray Computed: instrumentation /
                      Radiation Dosage / Humans / Radiotherapy Dosage / low
                      imaging dose (Other) / photon-counting CT (Other) /
                      quantitative imaging (Other) / radiotherapy (Other) /
                      spectral CT (Other) / virtual monoenergetic imaging (Other)},
      cin          = {MU01},
      ddc          = {530},
      cid          = {I:(DE-He78)MU01-20160331},
      pnm          = {899 - ohne Topic (POF4-899)},
      pid          = {G:(DE-HGF)POF4-899},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:41082908},
      doi          = {10.1088/1361-6560/ae128c},
      url          = {https://inrepo02.dkfz.de/record/305672},
}