Chapter 7 (Radiologic Science for Technologists 11e) Questions with Complete Solutions

Kinetic energy - energy of motion Kinetic Energy equation - KE=1/2mv^2 The distance between the filament and the x ray tube is approximately........ - 1cm Most kinetic energy of electrons is converted to........ - heat Approximately what percentage of the kinetic energy of electrons is converted from the cathode to heat? - 99% What percentage of electric kinetic energy is used for the production of x rays? - 1% Doubling the x ray tube currents also doubles the......... - heat produced If the electron interacts with an inner-shell electron of the target atom rather than the outer-shell, what type of x rays can be produced? - Characteristic x rays When are characteristic x rays emitted? - when an outer shell electron fills an inner-shell void. K shell binding energy # - 69 (Kev) L shell binding energy # - 12 (Kev) M shell binding energy # - 3 (Kev) N shell binding energy # - 1 (Kev) O shell binding energy # - .1 (Kev) P shell binding energy # - none What type of characteristic x rays of tungsten are useful for imaging? - K Shell Characteristic x rays of tungsten Why call characteristic radiation characteristic? - because it is characteristic of the target element. Why is there an electrostatic force of attraction between the nucleus and the electron? - The electron is negatively charged and the nucleus is positively charged. In this type of interaction, the kinetic energy of the projectile electron is also converted to electromagnetic energy. - Bremsstrahlung How are Bremsstrahlung x rays produced? - When a projectile electron is slowed by the nuclear field of a target atom nucleus. Bremsstrahlung is a German word for....... - slowed down radiaton What type of x rays can be considered radiation that results from the braking of cathode electrons by the nucleus? - Bremsstrahlung In diagnostic range, most x rays are....... - Bremsstrahlung Can Bremsstrahlung x rays be produced at any energy? - yes For characteristic x rays to be produced, K characteristic x rays require an x ray tube potential of at leat......... - 69 or 70kVp At 100kVp approximately what percentage of the x ray beam is characteristic and the rest bremsstrahlung? - 15% A discrete spectrum contains....... - only specific values A continuous spectrum contains.... - all possible values. What type of x rays have a precisely (discrete) energies ad form a discrete emission spectrum? - Characteristic x rays What characteristic of x ray tungsten is the only sufficient energy to be of value in diagnostic radiology? - K x rays