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Title: A model to simulate the oxygen distribution in hypoxic tumors for different vascular architectures

Purpose: As hypoxic cells are more resistant to photon radiation, it is desirable to obtain information about the oxygen distribution in tumors prior to the radiation treatment. Noninvasive techniques are currently not able to provide reliable oxygenation maps with sufficient spatial resolution; therefore mathematical models may help to simulate microvascular architectures and the resulting oxygen distributions in the surrounding tissue. Here, the authors present a new computer model, which uses the vascular fraction of tumor voxels, in principle measurable noninvasively in vivo, as input parameter for simulating realistic PO2 histograms in tumors, assuming certain 3D vascular architectures.Methods: Oxygen distributions were calculated by solving a reaction-diffusion equation in a reference volume using the particle strength exchange method. Different types of vessel architectures as well as different degrees of vascular heterogeneities are considered. Two types of acute hypoxia (ischemic and hypoxemic) occurring additionally to diffusion-limited (chronic) hypoxia were implemented as well.Results: No statistically significant differences were observed when comparing 2D- and 3D-vessel architectures (p > 0.79 in all cases) and highly heterogeneously distributed linear vessels show good agreement, when comparing with published experimental intervessel distance distributions and PO2 histograms. It could be shown that, if information about additional acute hypoxia is available,more » its contribution to the hypoxic fraction (HF) can be simulated as well. Increases of 128% and 168% in the HF were obtained when representative cases of ischemic and hypoxemic acute hypoxia, respectively, were considered in the simulations.Conclusions: The presented model is able to simulate realistic microscopic oxygen distributions in tumors assuming reasonable vessel architectures and using the vascular fraction as macroscopic input parameter. The model may be used to generate PO2 histograms, which are needed as input in models predicting the radiation response of hypoxic tumors.« less
Authors:
 [1] ;  [2] ;  [3]
  1. Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany and Department of Physics, Pontificia Universidad Católica de Chile, Santiago 7820436 (Chile)
  2. Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg 69120 (Germany)
  3. Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg 69120 (Germany)
Publication Date:
OSTI Identifier:
22220503
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 40; Journal Issue: 8; Other Information: (c) 2013 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANIMAL TISSUES; ANOXIA; BIOCHEMISTRY; BLOOD VESSELS; COMPUTERIZED SIMULATION; DIFFUSION EQUATIONS; IN VIVO; NEOPLASMS; OXYGEN; RADIOTHERAPY; SPATIAL RESOLUTION