Biological Effects of Radiation


This curricular unit aims to provide a comprehensive understanding of the effects of ionizing radiation in biological systems. Mainly, it seeks to provide understanding of the interaction of ionizing radiation with matter on the molecular level and how molecular-level effects lead to damage at the cell and tissue levels.

At the end of this curricular unit, students should be able to:

  1. Understand the effect of radiation on atoms and molecules;
  2. Distinguish between different mechanisms of damage at the molecular level;
  3. Understand the systems of defense, and repair, against radiation damage;

Critically review the scientific literature pertinent in this field.

General characterization





Responsible teacher

Pedro António de Brito Tavares


Weekly - 2

Total - 30

Teaching language



Optional. No mandatory requirements.


  1. “Radiation Biology: A Handbook for Teachers and Students”, training course series no. 42, International Atomic Energy Agency, Vienna, 2010.
  2. “Essentials of Radiation, Biology and Protection”, Steve Forshire, Delmar Cengage Learning; 2 edition, 2008.
  3. Vários artigos publicados em revistas científicas internacionais.

Teaching method

The contents of the curricular unit will be presented in two classes: i) theoretical classes, illustrated whenever possible with practical cases; and ii) seminar classes, that will include presentation and group discussion of an article published in an international journal. It will also be asked that students prepare an individual essay in specific chosen themes. Evaluation will take into account the presentation (50%) and the essay (50%).

Evaluation method

The final grade will be calculated by the following formula:

NF = 0,45 x A + 0,10 x P + 0,45 x G


NF = final graderounded to the units;
A = Presentation of a lecture on the subject of a chosen scientific articlerounded to one decimal value;

P = Question to others presentation;
G= Group assignment
rounded to one decimal value;

To obtain frequency it is required to attend 70of the lectures.

Subject matter

1. Introduction and Historical Perspective

2. Sources and types of Ionizing Radiation

  • Particulate vs. Electromagnetic
  • Atomic structure, origin and nature of ionizing radiation
  • Radiation dose and units
  • Principles of radiation dosimetry
  • Interaction of radiation with matter

3. Introduction to Radiation Chemistry

  • Water radiolysis
  • Free radical formation
  • Direct vs indirect effects

4. Radiation-induced cell death

  • Survival curves in vivo and in vitro
  • Damage repair at the cellular level
  • Dose rate effects

5. Radiation effects on cell cycle

6. Antioxidants

7. Radiation Effects on DNA

  • Type of damage caused by ionizing radiation
  • Radiation induced mutations
  • Chromosome and chromatid aberrations
  • DNA repair mechanisms

8. Radiation effects on proteins and lipids