Radiation Oncology/Radiobiology/Radiosensitivity

  • 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
  • The most radio-sensitive cells:
    1. High division rate
    2. High metabolic rate
    3. Non-specialized type
    4. Well nourished
  • Casarett classification:
    1. Group I
    2. Group II
    3. Group III
    4. Group IV
  • Michalowski classification (PMID: 7127027):
    1. H-type (hierarchical): like hemopoietic tissues
    2. F-type (flexible): like liver parenchyma