OCR A Medical Physics

What is primarily responsible for the production of X-rays in X-ray tubes?

• The collision of electrons with a low-density gas

• The rapid deceleration of electrons colliding with a hard metal anode

• The emission of light from a heater or filament

• The acceleration of protons in a magnetic field

What type of emission is used in X-ray tubes to emit electrons from the cathode?

• Photoelectric emission

• Thermionic emission

• Field emission

• Secondary emission

Which type of radiation is described as being produced by the Bremsstrahlung process?

• Gamma rays

• Ultraviolet rays

• X-rays

• Infrared rays

What is the maximum kinetic energy that the electrons can gain in the described X-ray tube setup?

• 100keV

• 200keV

• 300keV

• 500keV

What is the primary use of a collimated beam in medical imaging?

• To increase the energy of X-rays

• To create a wider exposure area

• To direct the beam at specific parts of a patient’s anatomy

• To generate more heat at the anode

What is the purpose of a collimator in X-ray imaging systems?

• To focus the X-ray beam to a fine point

• To absorb any rays that are not parallel to the axis of the tubes

• To increase the energy of the X-rays

• To detect the X-rays after they pass through the body

What results from higher energy electrons transitioning down to unoccupied shell levels in anode atoms during X-ray generation?

• Decrease in X-ray intensity

• Emission of radiation with specific wavelengths

• Reduction in electron energy levels

• Increase in the speed of electrons

What is the primary health risk associated with the ionization of matter by X-rays?

• Increased blood flow

• Thermal damage to tissues

• Ionization of DNA and other tissues causing mutations

• Enhanced metabolic activity

How do X-rays contribute to cancer treatment according to the text?

• By enhancing the growth of healthy cells

• By reducing the number of cancer cells without excessive damage to healthy tissue

• By increasing the energy levels of cancer cells

• By cooling the affected area

What is the term used to describe the reduction in intensity of an X-ray beam as it passes through a material?

• Reflection

• Refraction

• Attenuation

• Diffraction