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2013

Geometry of tumor growth in brain

Miguel Martín-Landrove, Francisco Torres-Hoyos

 

Revista de la Facultad de Ingeniería U.C.V., Vol. 28, N° 4, pp. 79-­88, 2013 [article in spanish]

 

The tumor growth can be characterized by using scaling analysis methods performed on the tumor interface, a procedure results obtained through a scaling analysis are shown for tumor lesions in brain, of primary origin, either malignant or benign and metastases. To evaluate different proposed models for tumor growth in brain, several growth simulations for primary brain tumors or gliomas were performed assuming a simple growth model, described through a reaction-­diffusion differential equation or in this context, a proliferation-­invasion equation. The term associated to the proliferation is from logistic type, to take into account the limitation of nutrients and oxygen resources imposed on tumor cells. In order to consider the differences between grey and white matter in the diffusion parameters, the simulations used the brain tissue’s database provided by BrainWeb. Simulations were performed for different relations between the diffusion parameters (invasion) and the reaction parameters (proliferation) covering growth conditions from low grade gliomas up to high grade gliomas (glioblastoma multiforme). The scaling analysis results show a close correspondence with previously results revealed in tumor magnetic resonance images, which suggest that the simple model used for the computer simulations describes in an appropriate manner tumor growth of glioma in the brain and that its use could be extended for describing the brain metastases.

Contribution of (n,γ ) reaction in the out-of-field absorbed dose for patients under radiotherapy treatments with high MV linear accelerators

R. Martín-Landrove, L. Sajo-Bohus, L. Spencer, D. Palacios, J. Dávila

 

X Latin American Symposium on Nuclear Physics and Applications, Montevideo, Uruguay, December 1-6, 2013

 

An alternative approach based on transport theory and neutron mean free paths for different tissues allows the estimation of the absorbed dose due to photo-neutrons in radiotherapy treatments for 15 MV linear accelerators. The contribution of neutron induced reactions to the out-of-field absorbed dose is evaluated in detail for every relevant process and the enhancement effect on the absorbed dose which is produced by multiple scattering is included. Although a risk/benefit analysis indicates that in general such a neutron field does not pose a significant health hazard, a sound recommendation is to avoid this kind of treatment for children.

Nuclear track evolution by capillary condensation during etching in SSNT detectors

R. Martín-Landrove, L. Sajo-Bohus, D. Palacios

 

Radiation Measurements 50 (2013) 241e245

 

The microscopic process taking place during chemical etching is described in terms of a dynamic framework governed by capillary condensation. The aim is to obtain physical information on how the cone shaped tracks with curved walls evolve during chemical etching under a close examination of first principles. The results obtained with the proposed theory are compared with published values to establish their range of validity.

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