Which of the following statements is false
It is impoant to recognize that hypoxia in tumours can result from two quite different mechanisms. Chronic hypoxia results from the limited diffusion distance of oxygen through tissue that is respiring. The distance to which oxygen can diffuse is largely limited by the rapid rate at which it is metabolized by respiring tumour cells. Many tumour cells may remain hypoxic for long periods of time. In contrast to chronic hypoxia, acute hypoxia is the result of the temporary closing of a tumour blood vessel owing to the malformed vasculature of a tumour, which lacks smooth muscle and often has an incomplete endothelial lining and basement membrane. Tumor cells are exposed to a continuum of oxygen concentrations, ranging from the highest in cells surrounding the capillaries to almost anoxic conditions in cells more distant from the capillaries. This is significant because both chronic and acute hypoxia has been shown to drive malignant progression.Reference: Eric J Hall Textbook of Radiobiology for Radiologist; 5th edition
Hypoxia in tumours can result from two different mechanisms: chronic hypoxia and acute hypoxia
Acute hypoxia is caused by a temporary closing of a blood vessel in the tumour
Chronic hypoxia is caused by the limited diffusion distance of oxygen through tissue that is respiring
Oxygen does not affect the radiosensitivity of tumours
Radiotherapy