Radiation Biology


  • Lecture Series in Biology is a little old (2004), but it is delivered predominantly by one of the major league players in cancer biology - Robert A. Weinberg. He presented one of the keynote addresses on non-genomic cancer biology at ASTRO 2008 which was superb.
  • The On-Line Biology Book is the effort of Michael J. Farabee, Ph.D, a lecturer in Estrella Mountain Community College (Avondale, AZ).


Phase 1 Assignment material

I'll do my best to help, you must tell me which assignment, and which question you wish to get help with. Please SEND ME THE TEXT of the question, even if it is a repeat so that there is no confusion (it is after all just a copy & paste!).

I shall attempt to help you get answers rather than providing answers for you, and I will explain things in those resources if needed.

Phase 1 Assignments

Other Radiobiology things


Clinical Cases in Radiobiology

Somatic cells are classified as:

  • Stem cells, which exists to self-perpetuate and produce cells for a differentiated cell population.
  • Transit cells, which are cells in movement to another population.
  • Mature cells, which are fully differentiated and do not exhibit mitotic activity.

Radiation is classified into two main categories:

  • Non-ionizing radiation (cannot ionize matter)
    • radio waves, light, microwaves
  • Ionizing radiation (can ionize matter)
  • Directly ionizing radiation (charged particles)
    • electrons, protons, alpha particles, heavy ions
  • Indirectly ionizing radiation (neutral particles)
    • photons (x rays, gamma rays), neutrons

In radiobiology and radiation protection the linear energy transfer (LET) is used for defining the quality of an ionizing radiation beam and focuses attention on the linear rate of energy absorption by the absorbing medium as the charged particle traverses the medium, while the stopping power focuses attention on the energy loss by a charged particle moving through a medium. The ICRU defines the LET as the quotient

$LET = {dE \over dl}$

where dE is the average energy locally imparted
to the medium by a charged particle of specified energy
in traversing a distance dl.

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