Author of

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  P3.08 - Poster Session 3 - Radiotherapy (ID 199)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Radiation Oncology + Radiotherapy
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 12554

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    P3.08-010 - The potential use of MRI to delineate lung cancer volumes for radiotherapy (ID 1344)

    09:30 - 09:30  |  Author(s): G. Liney
    • Abstract

    Background
    The use of MRI for lung cancer volume delineation for radiotherapy is rare. This has been due to poor image quality as a result of physical and physiological factors such as low proton density, susceptibility effects and respiratory and cardiac motion. However as MRI technology has improved, imaging of lung abnormalities has become more feasible. A prospective study was therefore conducted to evaluate image quality for lung tumour delineation on a 1.5T (Tesla) and 3T MRI scanner. The aim of the study was to identify potential scan sequences that could be used clinically for tumour delineation for radiation therapy treatment.

    Methods
    Ten patients with lung cancer underwent MRI, five on a 1.5T GE scanner using a body phased array coil and five on a 3T Phillips scanner. Scans on the 1.5T scanner were undertaken with breath hold and scans on the 3T scanner were performed with respiratory and peripheral pulse gating to give optimal image quality. The thorax was imaged with T2 and T1 weighted sequences on both field strengths. Cine mode imaging to compare tumour motion was also acquired. Scan sequence was matched for the 1.5T and 3T scanners. The quality of images for lung cancer delineation was assessed by an experienced thoracic radiologist and thoracic radiation oncologist using a four point scale. A consensus score ranging from 1(superior) to 4 (inferior) was given for each sequence based on four categories; tumour edge detection, image artefacts, noise affecting edge detection and overall image quality. A score of 2 or below was considered clinically acceptable

    Results
    Both magnet strengths provided reasonable image quality to define tumour volume on lung MRI. The average score for overall image quality between the two scanners was 1.8 for 1.5T and 1.3 for the 3T scanner. For the 1.5T scanner the sagittal and coronal T2 weighted scan scored the best for overall image quality for tumour delineation (1.53), due to limited respiratory motion distortion. However these image planes are not compatible with radiotherapy planning systems. For the 3T scanner the axial T2 images scored best for overall image quality (1.05). For tumour edge detection the sagittal and coronal and T1 weighted images scored best (1.75) for the 1.5T scanner. The axial T2 weighted image and the sagittal cine mode performed best for tumour edge detection (1). Overall sequences on the 3T scanner were rated higher than those on the 1.5T scanner

    Conclusion
    It is feasible to utilise commercially available MRI sequences to acquire images of acceptable quality for the purposes of lung cancer delineation in radiotherapy. Both magnet strengths gave acceptable image quality for clinical use in radiotherapy, with the 3T magnet displaying slightly better image quality. A future study will compare lung cancer delineation between the current standard practice of CT&PET with MRI.