Virtual Library

Start Your Search

I. Feain



Author of

  • +

    MA13 - Modern Technologies and Biological Factors in Radiotherapy (ID 395)

    • Event: WCLC 2016
    • Type: Mini Oral Session
    • Track: Radiotherapy
    • Presentations: 1
    • +

      MA13.01 - Markerless Tumour Tracking during Lung Radiotherapy Using Intrafraction X-Ray Imaging (ID 5533)

      16:00 - 17:30  |  Author(s): I. Feain

      • Abstract
      • Presentation
      • Slides

      Background:
      Lung tumours often exhibit large and unpredictable motion that can severely compromise radiotherapy outcomes. Markerless tumour tracking can enable wide access to motion-adaptive radiotherapy, negating the risks and costs associated with implanting markers. The main barrier to markerless tumour tracking is the inferior tumor visibility on x-ray images due to overlapping anatomic structures. The aim of this study is to develop a markerless tumor tracking method for lung radiotherapy using intrafraction x-ray imaging.

      Methods:
      The markerless tumour tracking method (Figure1a) consists of four steps: (1) Building a tumour and anatomic model from the cone-beam CT (CBCT) acquired prior to treatment, (2) Using the anatomic model to remove the contribution of anatomic structures on intrafraction x-ray images, (3) Locating the tumour on the intrafraction 2D x-ray image via template matching using the tumour model, (4) Determining the tumour 3D position by a Kalman filter. The proposed method was retrospectively validated on (i) 11 CBCT scans from four patients with central tumours, and (ii) a kV fluoroscopic scan during a stereotactic ablative radiotherapy (SABR) treatment from the Light SABR trial (NCT02514512). Tracking errors were estimated using the motions of markers or beacons implanted near the tumours. Figure 1



      Results:
      Markerless tumour tracking successfully tracked tumours in all cases at every imaging angle. The mean 3D tracking error ranged from 1.8-4.1mm for the 11 CBCT scans, and was 3.0mm for the SABR case. Compared with the current standard of care, i.e. a single estimation of tumour position prior to treatment from the pre-treatment CBCT, markerless tumour tracking reduced tumour localization error by 0.9-7.9mm. Tracking errors in the left-right, superior-inferior, and anterior-posterior directions are shown in Figure1b.

      Conclusion:
      A markerless tumour tracking method was developed and shown to improve tumour localization accuracy in 12 lung cancer cases. This method can potentially enable wide access to motion-adaptive radiotherapy.

      Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.

      Only Active Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login or select "Add to Cart" and proceed to checkout.