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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:30 |
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Conference: Bucharest University Faculty of Physics 2016 Meeting
Section: Biophysics; Medical Physics
Title:
Radiobiological Models - Implications in Evaluation and Optimization of External Beam Planning
Authors:
Alina TANASE (1), Mihai DUMITRACHE (1)
Affiliation:
1) Emergency Central Military Hospital”Dr. Carol Davila”, Bucharest, Romania
E-mail
alinatanasemail@yahoo.com
Keywords:
Radiobiological models, evaluation, optimisation, radiotherapy, tumour control, normal tissue complications
Abstract:
Currently, evaluation and optimisation process of radiotherapy planning is mainly based on absorbed dose distribution in planning target volume (PTV) and at level of organs at risk. Dose volume histogram (DVH) plays an important role in this analysis, but under modern radiotherapy, where every detail counts, this set of information is not sufficient. DVH includes a link between physical volume geometry and dose distribution. However, based on certain technical considerations, we approach the physical limits of the used systems to obtain a conformal dose distribution in the treated volume. In this situation, the radiobiological component introduction in treatment planning process becomes an extremely important tool, especially in terms of a multidisciplinary approach. The primary goal of radiobiology modelling is to predict a clinical outcome under the physician and medical physicist constraints. Based on this information, the treatment aim will be to maximize the probability of tumour control as well as the controlled radiobiological impact of critical structures. Using the concept of biologically equivalent uniform dose, EUD, firstly introduced by Niemierko (1999), which considered that the dose distributions may be equivalent if they lead to the same radiobiological effect and taking into account local tumour control, we tried an implementation of concepts by computer simplified simulation for two clinical cases (head and neck; prostate. Advanced development of this model may enable more detailed subsequent checks in order to improve the treatment strategies. Also, we have to take into account the uncertainties of the model, in terms of tumour control and normal tissue complications. Moreover, inter-patient variations and cellular radiosensitivity are also subjects of uncertainties. For these reasons, the radiobiological models should be used with caution and not as primary tools of analysis.
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