Exam 25: Electron Beams in Radiation Therapy

Which technique is most likely to result in photon contamination of the electron beam?

Which of the following is one very important consideration during the use of internal shields when administering electron therapy?

Which processes are responsible for electron interactions with matter? I.Collisional processes II.Radiation processes III.Gradient processes

Which of the following is not an application of bolus when used with electron beams?

Which electron beam's diameter (field size)is most likely to have an effect on a 20-MeV beam's surface dose and percent depth dose?

What is the depth of the 80% isodose line of a 15-MeV electron beam?

Surface dose values for electron beams in the 6- to 20-MeV range vary from __________.

What will be the energy of an electron beam at a depth of 4 cm that had a surface energy of 16 MeV?

What is the practical range of a 25-MeV electron beam?

According to the Association of Physicists in Medicine (AAPM)Task Group 25 report, what distance is considered an extended source-skin distance (SSD)for electron beams?

What effect will an increase in the nominal energy of an electron beam have on the depth of the 80% isodose line?

Which processes are responsible for the majority of energy loss for electron energy ranges useful in radiation therapy? I.Collisional processes II.Radiation processes III.Gradient processes

What are electrons scattered with enough energy to cause further ionization and excitations in other atoms?

What thickness of lead is necessary to adequately shield a 9-MeV electron beam?

To produce a therapeutically useful electron beam, the stream of electrons leaving the electron gun must contact the ___________ before exiting the gantry head.

Given a mean energy of an electron beam is 6 MeV, what is the depth of the 50% isodose line?

Which process is responsible for the majority of energy loss for electron energy ranges useful in radiation therapy? I.Effective point source method II.Virtual source method

What is the depth of the 90% isodose line of a 9-MeV electron beam?

Which treatment energy for electrons is most likely to use a scanning beam technique rather than a scattering foil?

What is the danger to tissue in front of an internal shield when used with electron beams therapy?