15 M. Bardiès : Multiresolution dosimetry for radiotherapy optimization
Team Research Project
Team 15: (M. Bardiès): to establish patient-specific dosimetry as a means to optimize targeted radiotherapy
Targeted RadioTherapy (TRT) currently involves administering fixed amounts of radioactive drug for all cancer patients (“one size fits all”), eventually modulated by patient’s weight of body surface area, but disregarding patient’s specific uptake and washout of the radiopharmaceutical.
Implementing patient-specific dosimetry, based on the actual pharmacokinetics of the patient would significantly improve efficacy while confining toxicity to acceptable levels.
With this aim, our team optimizes the dosimetric process at all scales (cell, tissue, body) by quantifying activity distributions and modelling radiation transport for various emitters (alpha, beta, Auger) used for TRT.
Our project relies on funded national or international academic research programmes: PhysiCancer (2013-2015), ANR (2014-2018), MetroMRT (projects.npl.co.uk/metromrt/) (2013-2015), and industrial projects: Betalutin™ (2013-2016) and TheraneaM (ISI 2014-2018).
- At the cellular level, we develop and validate specific low-range particle radiation transport to assess the impact of cell type and morphology on energy deposition in sub-cellular compartments.
- Preclinical studies are performed within small-animal imaging facilities installed at Institut Universitaire du Cancer de Toulouse – Oncopole (IUCT-O):
- We develop procedures to validate in vivo pharmacokinetics determination in longitudinal studies for a variety of radiolabeled vectors.
- In parallel, we generate specific rodent dosimetric models to give account of energy delivered in small animal TRT.
- At the clinical scale, we focus on the assessment of uncertainties associated with TRT dosimetry. Our project, DosiTest (www.dositest.com), is based on Monte-Carlo modelling of scintigraphic imaging and energy deposition in realistic anthropomorphic phantoms.
- We intend to perform a virtual, multicentric clinical trial to determine the critical steps associated with clinical dosimetry.
This fundamental research on radiation effects will be applied to TRT clinical trials implemented in Nuclear Medicine Depts at IUCT-O (Lutathera™, Xofigo™) and Toulouse University Hospital (Radioembolization), to individualize Nuclear Medicine therapies.
Beside Nuclear Medicine, we intend to expand our research activities in direction of external beam radiotherapy and eventually proton-therapy (project Pericles).
We participate to student education via Toulouse Master of Medical Physics http://rmgbm.free.fr
- Dosimetry: absorbed dose (J/kg, or Gy) assessment. For external beam radiotherapy, dosimetry is mostly based on reference measurements of the high-energy photon beams produced by the accelerators. In Nuclear Medicine, dosimetry relies on calculations performed after radioactive source localisation (quantitative scintigraphic imaging).
- Monte-Carlo modelling: Assessment of radiation-matter interactions, based on the stochastic nature of radiation emission, transport and energy deposition. Heavily used in Medical Physics, both for imaging and dosimetry. Gate (http://www.opengatecollaboration.org) is one of the most popular codes in Nuclear Medicine.