Publications [#63197] of Mark W. Dewhirst

Papers Published

1. Kavanagh, Brian D. and Secomb, Timothy W. and Hsu, Richard and Lin, Peck-Sun and Venitz, Jurgen and Dewhirst, Mark W., A theoretical model for the effects of reduced hemoglobin-oxygen affinity on tumor oxygenation, International Journal of Radiation Oncology Biology Physics, vol. 53 no. 1 (2002), pp. 172 - 179 [S0360-3016(02)02740-2]
   (last updated on 2007/04/14)

   Abstract:
   Purpose: To develop a theoretical model for oxygen delivery to tumors, and to use the model to simulate the effects of changing the affinity of hemoglobin for oxygen on tumor oxygenation. Methods and Materials: Hemoglobin affinity is expressed in terms of P₅₀, the partial pressure of oxygen (Po₂) at half saturation. Effects of changing P₅₀ on arterial Po₂ are predicted using an effective vessel approach to describe diffusive oxygen transport in the lungs, assuming fixed systemic oxygen demand and fixed blood flow rate. The decline in oxygen content of blood as it flows through normal tissue before entering the tumor region is assumed fixed. The hypoxic fraction of the tumor region is predicted using a three-dimensional simulation of diffusion from a network of vessels whose geometry is derived from observations of tumor microvasculature in the rat. Results: In air-breathing rats, predicted hypoxic fraction decreases with moderate increases in P₅₀, but increases with further increases of P₅₀, in agreement with previous experimental results. In rats breathing hyperoxic gases, and in humans breathing either normoxic or hyperoxic gases, increased P₅₀ is predicted to improve tumor oxygenation. Conclusions: The results support the administration of synthetic agents to increase P₅₀ during radiation treatment of tumors. © 2002 Elsevier Science Inc.

   Keywords:
   Tumors;Hemoglobin;Oxygen;Diffusion in liquids;Blood;Tissue;Mathematical models;Computer simulation;Partial pressure;