Magnetic Resonance-Based Treatment Planning for Prostate Intensity-Modulated Radiotherapy: Creation of Digitally Reconstructed Radiographs

Lili Chen, Thai Binh Nguyen, Élan Jones, Zuoqun Chen, Wei Luo, Lu Wang, Robert A. Price, Alan Pollack, C. M.Charlie Ma

Research output: Contribution to journalArticle

34 Scopus citations


Purpose: To develop a technique to create magnetic resonance (MR)-based digitally reconstructed radiographs (DRR) for initial patient setup for routine clinical applications of MR-based treatment planning for prostate intensity-modulated radiotherapy. Methods and Materials: Twenty prostate cancer patients' computed tomography (CT) and MR images were used for the study. Computed tomography and MR images were fused. The pelvic bony structures, including femoral heads, pubic rami, ischium, and ischial tuberosity, that are relevant for routine clinical patient setup were manually contoured on axial MR images. The contoured bony structures were then assigned a bulk density of 2.0 g/cm3. The MR-based DRRs were generated. The accuracy of the MR-based DDRs was quantitatively evaluated by comparing MR-based DRRs with CT-based DRRs for these patients. For each patient, eight measuring points on both coronal and sagittal DRRs were used for quantitative evaluation. Results: The maximum difference in the mean values of these measurement points was 1.3 ± 1.6 mm, and the maximum difference in absolute positions was within 3 mm for the 20 patients investigated. Conclusions: Magnetic resonance-based DRRs are comparable to CT-based DRRs for prostate intensity-modulated radiotherapy and can be used for patient treatment setup when MR-based treatment planning is applied clinically.

Original languageEnglish (US)
Pages (from-to)903-911
Number of pages9
JournalInternational Journal of Radiation Oncology Biology Physics
Issue number3
StatePublished - Jul 1 2007
Externally publishedYes



  • MR-based DRRs
  • MRI treatment planning
  • Prostate cancer
  • Radiotherapy

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Radiation

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