Evaluation by Monte Carlo Simulation of Doses Distribution in Tumors with Hypoxia

Mirko Salomón Alva-Sánchez,Thatiane Alves Pianoschi

doi:10.5772/intechopen.90611

Abstract

Radiotherapy is one of the most useful modalities applied for tumor treatments, which use ionization radiation to eradicate the tumor, in major cases. Cells with normal oxygenation are more sensitive to the effects of ionizing radiation than those with hypoxic conditions, because O2 molecules react rapidly with free radicals, produced by irradiation, originating highly reactive radicals. Thus, the different concentrations of hypoxia in tumors can modulate the response of the irradiation through the radioresistance they present and consequently the success of the treatment. This chapter deals with the dose distributions in cranial tumors with different concentrations of hypoxia through a code based on Monte Carlo simulation.

Highlights

The modality of treatment with ionization radiation, for cancer can be considered routinely in several hospital centers, which must have human and technological resources capable of conforming the radiation dose into the target volumes and trying to avoid high toxicity in the adjuvant tissues. All these resources exist, the treatment planning is based on prior knowledge of the structures of the patient that can be obtained through any kind of medical images
Experimental data showed that oxygen is the most component that modified the radiation sensitivity and hypoxic cells that can be 2–3 times more resistant to ionizing radiation, which would imply administering doses higher than doses to achieve the same effect in oxygenated cells under normal conditions [2–4]
An important concept in clinical radiobiology is that the tumor may have subpopulations in hypoxic areas, leading to success of radiotherapy

Summary

Introduction

The modality of treatment with ionization radiation, for cancer can be considered routinely in several hospital centers, which must have human and technological resources capable of conforming the radiation dose into the target volumes and trying to avoid high toxicity in the adjuvant tissues. All these resources exist, the treatment planning is based on prior knowledge of the structures of the patient that can be obtained through any kind of medical images. An important concept in clinical radiobiology is that the tumor may have subpopulations in hypoxic areas, leading to success of radiotherapy. The low concentration of oxygen or hypoxia in the tumor tissues is a radiobiological phenomenon that has been observed since the beginning of the twentieth century [6]

Methods

Results

Conclusion