CLINICAL MEDICINE

Detailed explanation-1: -Radiosensitivity depends on several factors. These factors include the ability to repair damage, hypoxia, cell cycle position, and growth fraction. In addition, the volume of the initial tumor has been demonstrated to influence the ability to eradicate tumors.

Detailed explanation-2: -Radiosensitivity is the relative susceptibility of cells, tissues, organs, organisms, or other substances to the injurious action of radiation. In general, it has been found that cell radiosensitivity is directly proportional to the rate of cell division and inversely proportional to the degree of cell differentiation.

Detailed explanation-3: -Cells are least sensitive when in the S phase, then the G1 phase, then the G2 phase, and most sensitive in the M phase of the cell cycle. This is described by the ‘law of Bergonié and Tribondeau’, formulated in 1906: X-rays are more effective on cells which have a greater reproductive activity.

Detailed explanation-4: -However, based on the generalized target model, it can be concluded that the cellular radiosensitivity is determined by the cellular repair capacity.