Quantitative determination of hypoxia in tumours using MRI for adaptive radiotherapy

Hypoxia can be defined as the condition in which the body or areas of the body are lacking in adequate supply of oxygen at the tissue level. The condition is not common in normally functioning tissue but frequently appears in tumours and is often described as a characteristic feature of tumours. Tumour hypoxia can originate by means of perfusion, diffusion or anaemia related causes. It is known that the vasculature of tumours is distorted due to inefficient blood flow inside the tumour. As a result the oxygenation status of a tumour varies considerably. It is known that hypoxic regions are three to four times more resistant to radiotherapy as compared to normoxic tumour cells. Therefore in the treatment of cancer, treatment plans need to be designed that take into consideration tumour specific biological data on an individual basis. In order to achieve this, more quantitative data is needed such as cellular density, oxygen concentrations, vascular density, blood fractions, and so on. Therefore, this thesis discussed the methods involved in the quantitative determination of hypoxia in tumours using Magnetic Resonance Imaging (MRI) so that efficient radiotherapy treatment may be administered to cancer patients.