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Apport de la modulation d'intensité et de l'optimisation pour délivrer une dose adaptée aux héterogénités biologiques

Abstract : The recent progress in functional imaging by Positron Emission Tomography (TEP) opens new perspectives in the delineation of target volumes in radiotherapy. The functional data is major; we can intend to adapt the irradiation doses on the tumor activity (TA) and to perform a dose escalation. Our objectives were (i) to characterize the TEP thresholding, by quantifying the uncertainties of the target volume contour according to the lesion size and the threshold contour level, (ii) to set up the geometry suited to perform a high-precision irradiation based on the TA, (iii) to estimate the dosimetric impact of this new protocol and (iv) to verify that dosimetry is perfectly distributed. Three original phantoms were specially created to satisfy the constraints met, as well as two virtual phantoms containing 3 dose levels (dose level 3 =TA). Our results showed the importance of the effect threshold-volume on the planning in radiotherapy. To use this irradiation method, the diameter of 1cm for the 3rd level was able to be reached. A dose escalation of 20Gy was possible between the 2nd (70Gy) and the 3rd level (90Gy). The dosimetric impact estimated on two real cases was suitable (increase of COIN from 0.6 to 0.8 and decrease of NTCP of a factor 5). In absolute and relative dosimetry, the clinical tolerances were respected. So all the treatment process, going from the diagnosis with the TEP to reveal the TA, to the patient treatment made beforehand on phantom, and going through the ballistic and the dose calculation, was estimated and validated according to our objective to adapt the irradiation to the biological heterogeneities. However such high doses should be carefully estimated before being prescribed clinically and progress is also expected in imaging, because the minimal size which we can irradiate is on the limit of the resolution TEP.
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Contributor : Didier Wolf <>
Submitted on : Thursday, October 25, 2007 - 3:41:28 PM
Last modification on : Friday, October 23, 2020 - 4:33:03 PM
Long-term archiving on: : Monday, April 12, 2010 - 12:40:42 AM


  • HAL Id : tel-00182354, version 1



Fleur Kubs. Apport de la modulation d'intensité et de l'optimisation pour délivrer une dose adaptée aux héterogénités biologiques. Traitement du signal et de l'image [eess.SP]. Institut National Polytechnique de Lorraine - INPL, 2007. Français. ⟨tel-00182354⟩



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