ICTEAM > ISPGroup > Projects > InVivoDGT


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Project Description

The treatment of cancer by proton therapy has several advantages over photon radiotherapy. One advantage is the increased conformation of the dose to the target volume allowing therefore, on the one hand, an increase of the delivered dose to improve the therapeutic efficiency, and on the other hand, a decrease of the toxicity of the treatment.

However, the increased accuracy is a double-edged sword. Indeed, the treatment lasts for several weeks and for each fraction, the alignment between the tumour and the beam must be achieved. Any deviation can lead to an under-dose to the tumour and/or an over-dose to the surrounding organs at risk. Therefore, the advantages of proton therapy can be fully exploited only if the patient alignment devices, such as imaging before each fraction, are combined with means to predict and/or control whether the dose that was or will be delivered complies with the treatment plan. Eventually, this information will be used in order to modify the treatment parameters or the beam properties in order to adapt to the daily patient settings and the evolution of the disease.

The project aims to shift from Image Guided Proton Therapy (IGPT) to Dose Guided Proton Therapy (DGPT) so as to allow the visualisation and quantification of the delivered dose (simulation and measurements) in order to comply with the prescription with a precision of 5% in the CTV (Clinical Target Volume). The compliance will be evaluated from the deviation to the planned DVH (dose volume histogram) while including the dynamic motion of the tumour due to breathing and the morphological variations occurring during the course of the treatment.

This objective meets the needs in proton therapy to predict or measure for each daily fraction that the dose will be (or was) optimally delivered in order to adapt the treatment to the evolution of the disease. This will be the way to new strategies of adpatative treatments for tumour types that cannot currently be treated in proton therapy.

The project is a joint project between the UCL (ISP Group and the Molecular Imaging Radiotherapy and Oncology research group) and IBA. It is led by the iMagX research group.

Project steps

Improving imaging for dose computation thanks to quantitative imaging techniques by using:

  • Imaging to quantify the physical properties required for the computation of the dose deposition. The CBCT will be adapted using reconstruction algorithms and a priori information from the planning CT scan. A better description of the atomic composition of the tissues will be achieved by using MRI and proton radiography.
  • Dynamic imaging to account for tumour motion by 4D-CT and 4D-CBCT in order to simulate the dose deposition in presence of motion.

Design of dose mapping tools will allow merging into in situ images of the patient, the simulated and measured dose distribution by:

  • Simulation prior to irradiation. The deposited dose is simulated based on the current patient configuration (static and dynamic images) and the treatment plan by using simplified physical models and by parallelising the implementation.
  • Control of the dose by measurement of the proton range during irradiation using a prompt gamma detector
  • Determination of the total deposited dose using co-registration algorithms to register the daily dose maps to a common reference frame.

Assessment of new treatment strategies for proton therapy, e.g. by intra-fraction treatment adaptation (e.g. real time correction of beam position) or inter-fraction adaptive therapy. The impact of these strategies will be evaluated retrospectively by simulation and their sensitivity to breathing motions, positioning error and morphological changes will be assessed.

Partners

  • Massachussetts General Hospital (Harv. Med. School, Boston, MA, USA)
  • Centre de Protonthérapie d'Orsay (Institut Curie, Paris, France)
  • Roberts Proton Therapy Center (UPenn, Philadelphia, PA, USA)
  • ProCure (Warrenville, IL, USA)
  • University of Florida Proton Therapy Institute (Jacksonville, FL, USA)
  • RIH research group (T.U. Delft, NL)
  • Ludwig-Maximilians-Universität München (Munich, DE)

Funding

SPW - PPP (private public partnership) convention n°1217662

Dates

  • Start: 01/01/2013
  • End: 30/08/2015

Categories

ImageProcessing MedicalImaging Tomography MonteCarlo

ISPGroup Participant(s)

Related Research and Topics

ImagX Research Group: iMagX is a joint project between UCL (Université catholique de Louvain, Belgium) and IBA, world leader in proton therapy. Our interdisciplinary R&D team of 20 engineers, computer scientists, physicists and PhDs, works at the intersection of the scientific, clinical and industrial worlds, in order to create innovative imaging solutions to improve cancer treatment in proton therapy and radiotherapy.

Respiratory motion model of lungs and tumor from skin surface as surrogate for radiotherapy: Respiratory induced motion of organs and tumors is a technical challenge in radiation therapy since it compromises treatment accuracy. Recently available optical surface scanners have opened the door of modeling and predicting internal motion from external skin surface motion.




Last updated January 08, 2014, at 03:08 PM