◈ Which of the following can be defined as when any type of radiation deposits its energy directly in the critical target? 

A. Indirect action 

B. Radiolysis 

C. Elastic effect 

D. Isotonic effect 

E. Direct action 

◈ What reactive species exist in pure water at times >10^-12 s after irradiation but does not react further? 

A. OH· 

B. H₃O + 

C. H₂

D. H· 

E. e^-_eq

◈ A researcher can introduce various compartments of a eukaryotic cell with the radioisotope I-125, an emitter of short ranged gamma-rays and low-energy Auger electrons that deposit energy locally. When using the same amount of I-125 in each compartment, which is most likely to achieve cell kill? 

A. Cytoplasm 

B. Nucleus 

C. Endoplasmic reticulum 

D. Mitochondria 

E. Golgi apparatus 

◈ The DNA damage produced by ionizing radiation causes: 

A. Double strand breaks as the exclusive form of damage 

B. Irreparable damage 

C. Single strand breaks more frequently than double strand breaks 

D. Death for all cells exposed to ionizing radiation 

E. None of the above 

◈ What is the main reason for the difference in biologic effects caused by neutrons and photons? 

A. The energy of the radiation. 

B. The fact that the charged particles produced by neutrons are, for the most part, positively charged. 

C. The fact that neutrons can interact with nuclei. 

D. The density of ionization. 

E. None of the above