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@ARTICLE{Baader:304437,
      author       = {E. Baader$^*$ and M. Kachelriess$^*$},
      title        = {{R}isk-minimizing tube current and tube voltage modulation
                      for {CT}: {A} simulation study.},
      journal      = {Medical physics},
      volume       = {52},
      number       = {8},
      issn         = {0094-2405},
      address      = {Hoboken, NJ},
      publisher    = {Wiley},
      reportid     = {DKFZ-2025-01850},
      pages        = {e18047},
      year         = {2025},
      note         = {#EA:E025#LA:E025#},
      abstract     = {The optimal tube voltage in clinical CT depends on the
                      patient's attenuation and the imaging task. Although the
                      patient's attenuation changes with view angle and
                      longitudinal position of the X-ray tube, the tube voltage
                      remains constant throughout the scan in current clinical
                      practice. In general, the optimum tube voltage increases
                      with patient diameter. For iodine-enhanced scans, the tube
                      voltage is ideally low to increase contrast. However, 70 kV,
                      the lowest clinically available tube voltage today, can not
                      always be used due to tube current restrictions.To determine
                      the additional relative reduction in effective dose of a
                      tube voltage modulation in addition to a tube current
                      modulation for unenhanced and iodine-enhanced CT scans.For
                      patient models based on CT scans, the effective dose was
                      simulated per projection for different voltages using Monte
                      Carlo simulations. Using these dose data and analytical
                      estimations of noise and iodine contrast, tube voltage and
                      tube current curves were optimized for circular scans. For
                      unenhanced scans, the dose-weighted noise was minimized, and
                      for iodine-enhanced scans, the dose-weighted
                      contrast-to-noise ratio (CNRD) was maximized. The effective
                      dose values of the optimized tube voltage and tube current
                      curves (riskTCTVM) were compared at the same noise or same
                      contrast-to-noise ratio (CNR) to a pure tube current
                      modulation minimizing the effective dose (riskTCM) and to
                      conventional mAs-minimizing tube current modulation
                      (mAsTCM).For unenhanced scans, riskTCTVM reduces the
                      effective dose by less than 1 $\%$ $1 \,\\%$ compared to
                      riskTCM at its optimal tube voltage. For iodine-enhanced
                      scans, the effective dose benefit increases with the
                      availability of low tube voltages and the eccentricity of
                      the patient's anatomy. For a lowest voltage of 70 kV, we
                      found average effective dose benefits of riskTCTVM to
                      riskTCM of less than 3 \% $3 \,\\%$ for thorax and abdomen,
                      6 \% $6 \,\\%$ for the pelvis, and 14 \% $14 \,\\%$ for the
                      shoulder. For a lowest voltage of 50 kV, we found average
                      effective dose benefits of 7 \% $7 \,\\%$ for the thorax, 11
                      \% $11 \,\\%$ for the abdomen, 16 \% $16 \,\\%$ for the
                      pelvis, and 28 \% $28 \,\\%$ for the shoulder. However, the
                      maximum requested tube current was multiple times higher
                      than for mAsTCM at 70 kV. Only for eccentric anatomies in
                      the pelvis and the shoulder, riskTCTVM could lower tube
                      current demands for a lowest available voltage of 70 kV.For
                      unenhanced scans, tube voltage modulation in addition to a
                      modulated tube current yields a negligible effective dose
                      benefit. However, for iodine-enhanced circular scans, all
                      studied anatomical regions from shoulder to pelvis would
                      benefit from tube current and tube voltage modulation if
                      X-ray generators with voltages down to 50 kV were available
                      at sufficient tube power. For a lowest voltage of 70 kV,
                      riskTCTVM can considerably reduce the effective dose for
                      eccentric anatomies in the shoulder and the pelvis.},
      keywords     = {Tomography, X-Ray Computed: instrumentation / Tomography,
                      X-Ray Computed: methods / Tomography, X-Ray Computed:
                      adverse effects / Radiation Dosage / Humans / Monte Carlo
                      Method / Signal-To-Noise Ratio / Risk / computed tomography
                      (Other) / radiation risk (Other) / tube current modulation
                      (Other) / tube voltage modulation (Other)},
      cin          = {E025},
      ddc          = {610},
      cid          = {I:(DE-He78)E025-20160331},
      pnm          = {315 - Bildgebung und Radioonkologie (POF4-315)},
      pid          = {G:(DE-HGF)POF4-315},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:40903921},
      doi          = {10.1002/mp.18047},
      url          = {https://inrepo02.dkfz.de/record/304437},
}