Radiation Physics

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051
Across
  1. 1. After absorbing the neutron the nucleus splits into two nuclei of lower Z as well as giving off additional neutrons
  2. 3. the amount of energy present per unit of time per unit of area perpendicular to the beam direction
  3. 4. Low mass nuclei combine to form one nucleusmass released since the mass of the product particles is less than the mass of reactants
  4. 6. the difference between the actual weight and the sum of the constituent parts. (Two words)
  5. 10. ____ dose describes the quantity of radiation for all types of ionizing radiation, including charged and uncharged particles, all materials, and all energies
  6. 13. A type of scatter when an electromagnetic wave, passes near an electron and causes it to oscillate and the oscillating electron then re-irradiates the energy at the same frequency, and wavelength, as the incident e.m. wave
  7. 15. The time required for either that activity or the number of radioactive atoms to decay to half the initial value (two words)
  8. 17. treatment criteria for the plan optimization are given by the planner and the computer will determine what the correct leaf sequence is needed is considered _____ planning
  9. 18. The law in which the voltage across the total circuit or any portion of the circuit is equal to the current times the resistance.
  10. 20. affects the low energy portion of the spectrum by absorbing the low energy photons and hardens the beam
  11. 21. This type of therapy treats in the 50 to 150kV range and treats to a depth of 5mm or less
  12. 22. the scattering of photons away from the original point source
  13. 24. atoms having nuclei with the same number of Neutrons but different number of protons
  14. 25. a single fraction treatment for intracranial lesions using a combination of a specialized immobilization and narrow multiple beams delivered through Non-coplanar isocentric arcs (acronym)
  15. 27. technique in which a nonuniform fluence is delivered to the patient from any given position of the treatment beam to optimize composite dose distribution (acronym)
  16. 29. Elementary particle with a positive electric charge equal to that of an electron and a mass approximately to that of a neutron. found within the nucleus of the atom
  17. 30. Electron interacts with atom and ejects an orbital electron an outer shell orbital wants to fill that vacancy and the excess energy is given off as this type of x-ray
  18. 33. "type of radiotherapy wave maximizes reflecting waves at both ends as to give rise to stationary waves by combining forward and reverse traveling waves.
  19. 34. ratio of dose at a depth in a phantom to dose in free space at the same distance  (acronym)
  20. 37. Elementary particle with one negative charge that surrounds the positively charged nucleus and determines the chemical properties of the atom
  21. 41. A material that in some conditions behaves as a conductor but behaves like an insulator in other conditions
  22. 42. a type of phantom that uses materials to simulate body parts
  23. 43. A type of decay where the mass number is reduced by 4 and the atomic number is reduced by 2
  24. 46. Vacancy in orbital shell is filled by another electron and the transition energy is given off as characteristic x-ray (two words)
  25. 48. energy transferred from photons to electrons
  26. 49. type of radiotherapy wave that requires a terminating load to absorb the residual power at the end of the structure- to prevent backward reflecting wave
  27. 50. atoms having nuclei with the same number of Protons but different number of neutrons
Down
  1. 2. An insulator is any material that does not allow electron flow
  2. 5. same number of nucleons but different number of protons (different element)
  3. 7. the principle that energy absorbed in a medium from radiation appears ultimately as heat energy while a small amount may appear in the form of a chemical change
  4. 8. the region at the edge of a radiation beam over which the dose rate changes rapidly as a function of distance from the beam axis
  5. 9. measure of ionization produced in air by photons
  6. 11. uncharged elementary particle, with a mass slightly greater than that of a proton, that is found in the nucleus of every atom heavier than hydrogen
  7. 12. Radioactive decay accompanied by the ejection of a positive or negative electron from the nucleus
  8. 14. Thickness of a specified material that when introduced into the path of the beam, reduces the exposure rate by one half (acronym)
  9. 16. the incident particle does not have sufficient energy to eject an electron from the atom- so it raises the electrons to higher energy levels
  10. 19. "a dosimetry device used determine the optical density of the film which is a measure of the degree of blackening of the film
  11. 23. when an x-ray passes near an orbital electron of an atom and passes enough energy to the electron to remove it from the atom
  12. 24. same number of protons as well as neutrons- same elements but differ in the nuclear energy states… the last example has an isomer
  13. 25. this type of therapy treat 500 to 1000 kV and uses a transmission target
  14. 26. “Breaking” Radiation– electronic collision in which the electron passes near a nucleus and the columbic forces causing an ACCELERATION in which the electron MUST release energy
  15. 28. energy emitted and transferred through space
  16. 31. The Law in which the electrostatic force is directly proportional to the product of the electrostatic charges and inversely proportional to the SQUARE of the distance between them
  17. 32. "A law that states that the intensity of radiation at a location is inversely proportional to the square of its distance from the source of radiation. (two words)
  18. 35. the RATIO of the daughter activity to the parent activity remains constant over time.
  19. 36. component to the linac that includes pulse forming network and thyratron- high voltage pulses are flat topped DV pulses of few microseconds in duration.  These pulses are delivered to either the magnetron or klystron and simultaneously to the electron gun
  20. 38. Electron produced outside the collection region, which enter the ion-collecting region, is equal to the electron produced inside the collection region , which deposit their energy outside the region. (acronym)
  21. 39. the energy of the electron orbit, but with the opposite sign./The energy required to dissociate a structure. (two words)
  22. 40. this type of therapy treats in the 200 to 400 kV with the 90% isodose line at a depth of 2cm
  23. 44. A conductor is a substance through which electrons flow easily
  24. 45. component to the linac that Produces microwaves of several microseconds duration and a rep rate of several hundred pulses per second and Has cathode and anode in which electrons are generated by heating a filament within the cathode
  25. 47. a dosimetric device of tissue equivalence used to predict dose distribution in an actual patient
  26. 51. percentage of the absorbed dose at any depth d to the absorbed dose at a fixed reference depth along central axis (acronym)