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Dosimetrical Aspect of CT Simulation Role in Radiation Therapy Planning

  • Seyed Rabi Mahdavi
  • Alireza Nikoofar
  • Hamidreza Mirzaei
  • Bahram Mofid
Conference paper
Part of the IFMBE Proceedings book series (IFMBE, volume 25/1)

Abstract

Background: The dose distribution is affected by tissue inhomogeneities and purpose of this article is a dosimetric evaluation of corrective role of computerized tomographic (CT) data in radiotherapy treatment planning (RTP) for different parts of the body.

Method & materials: 54 cases of head&neck, pelvis, abdomen and breast cancers were included. All of them were imaged with same CT Scan. Each case was planned without and with CT-based density correction by a two dimensional ALFARD RTP system. Analysis of dosimetric parameters was done for with and without inhomogeneity corrections based on effective path length method. Dosimetric parameters are dose uniformity (Te), average (Davg), minimum (Dmin) and maximum (Dmax) doses for both the planning target volumes and organs at risk.

Results: Typical results of the mean differences (MD) between corrected and non-corrected dose parameters in TV’s were shown below.

Conclusion: Present study showed the role of CTS for dosimetric corrections. However, findings confirm that CT correction for density variation shows different improvements for different parts of the body. In some parts, if correction not applied, the dose deviations can be out of tolerance limits defined by standards for tumors and normal tissues.

Keywords

Radiotherapy planning density correction target volume organ at risk CT planning 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Seyed Rabi Mahdavi
    • 1
    • 3
  • Alireza Nikoofar
    • 1
  • Hamidreza Mirzaei
    • 2
  • Bahram Mofid
    • 2
  1. 1.Iran University of Medical SciencesIran
  2. 2.Assistant Professor of Radiation OncologySh. Beheshti University of Medical SciencesTehranIran
  3. 3.Dept. of Medical PhysicsIran University of Medical SciencesIran

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