Question

Concerning radio graphic contrast: 

a. Attenuation of the X-ray beam depends upon the degree of Bremsstrahlung in the tissue 

b. Most structures on a chest radio graph exhibit good radio  graphic contrast 

c. In principle, contrast media have the same effect on demonstrating contrast between tissues as increasing the peak kV (kVp) 

d. All contrast media attenuate X-rays to a higher degree than the tissue 

e. Positive-contrast media should generally have high atomic numbers to maximize the degree of photoelectric absorption

Answer 1

a. False. Attenuation is due to Compton scattering and photoelectric absorption. Bremsstrahlung relates to the production of X-rays. 

b. True. This is due to the different attenuation properties of air, fat, soft tissue and bone (the main four ‘radio graphic densities’).

c. False. As they improve contrast, their effect is analogous to decreasing the peak kV (kVp). 

d. False. Negative-contrast media (for example, air or carbon dioxide) are radio lucent. 

e. True.