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Développement méthodologique de l'application d'agents pharmacologiques renforçateurs de l'effet photoélectrique pour l'utilisation du rayonnement synchrotron en radiothérapie anticancéreuse

Abstract : Anticancer therapy rests on three main principles: 1) anatomic confinement of irradiation; 2) temporal fractioning of treatment; 3) treatment of tissues that are more sensitive to radiation than surrounding healthy tissue. Under those principles hides the goal of radiotherapy: to deposit more of the X-ray energy in the tumour while preserving the surrounding healthy tissues. This goal is hard to reach since one of the causes of the failures in radiotherapy is the continuing evolution of the tumour. Could synchrotron radiation be more effective as an X-ray source for radiotherapy? The variation of the radiation-matter interaction cross-sections as a function of X-ray energy and atomic number of the medium show that certain energies and certain elements are more suitable to obtain the largest number of interactions and the largest amount of deposited energy. Synchrotron radiation allows to select precisely those energies because of its high spectral intensity. Its spectral characteristics (energy of the photons between 10 and 100 keV) allow to trigger the photoelectric effect with a maximum of probability on heavy elements introduced close to cancerous cells. It has been shown that: 1) synchrotron radiation based tomodensitometry is a quantitative imaging technique, potentially powerful for radiotherapy since it insures in-vivo the measurement of intra-tumoral concentration of contrast agent (I or Gd); 2) in the presence of iodinated contrast agent the lethal effect of X-rays on cell survival is increased and the gain in radio sensitivity depends on X-ray energy ; 3) at the cellular scale the lethality of irradiation can be optimised again by transporting heavy atoms (I, Pt) inside the DNA, which is the biological target of the irradiation. This reinforcement of the killing efficiency of low energy X-rays using a physical mechanism aimed at a pharmacological agent is an original concept in anti cancer radiotherapy.
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https://tel.archives-ouvertes.fr/tel-00006585
Contributor : Stéphanie Corde <>
Submitted on : Tuesday, July 27, 2004 - 11:19:44 AM
Last modification on : Thursday, November 21, 2019 - 2:21:46 AM
Long-term archiving on: : Friday, April 2, 2010 - 8:24:38 PM

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  • HAL Id : tel-00006585, version 1

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Stéphanie Corde. Développement méthodologique de l'application d'agents pharmacologiques renforçateurs de l'effet photoélectrique pour l'utilisation du rayonnement synchrotron en radiothérapie anticancéreuse. Ingénierie biomédicale. Université Joseph-Fourier - Grenoble I, 2002. Français. ⟨tel-00006585⟩

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