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Radiation Biology 2010

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					                                 Introductory Radiation Biology
                                               Exam I

                                                2010



                      WHEREVER POSSIBLE, SHOW ALL WORK!!! AND UNITS!!!

                                      NO WORK, NO CREDIT!!!



1.   On his way to work, Dr. Lewis listens to KCMQ, broadcasting at a frequency of 96.7 MHz (9.67 ×
     107 s-1). What is the wavelength and energy (in eV) of these radio photons?




     153
2.      62Sm  (T1/2 = 46 h) is used for treatment of skeletal metastases in prostate and breast cancer
     patients, as well as for treatment of bone cancer in children and dogs. Drs. Stephanie Essman
     and Mike Lewis in the MU Department of Veterinary Medicine and Surgery studied the
     biological damage to growing bones caused by 153Sm, in order to learn how to make this
     treatment safer and more effective for children. 15362Sm decays exclusively to 15363Eu (stable),
     with a decay energy of 810 keV. In 72% of events, 15362Sm decays to the ground state of 15363Eu.
     In 28% of events, 15362Sm decays to an excited state that lies 103 keV above the ground state of
     153
        63Eu and de-excites to the ground state in less than 1 ns.




     a.        Sketch a decay scheme that is consistent with this information.
          153
     b.     Sm


                1.      is proton rich.
                2.      is neutron rich.
                3.      decays by isomeric transition.
                4.      can be used for nuclear power.


     c.         Given the conversion of matter to energy, which nuclide is lighter (i.e., has lower mass)?


                        153
                1.        Sm
                        153
                2.        Eu


     d.         At the University of Missouri Veterinary Medical Teaching Hospital (VMTH), Dr. Jim
                Lattimer treats dogs with bone cancer using the radiopharmaceutical 153Sm-EDTMP,
                produced by the University of Missouri Research Reactor (MURR). At MURR, a dose of
                100 mCi of 153Sm-EDTMP is prepared for shipment to the VMTH at 1:00 pm on Monday,
                and Dr. Lattimer needs 20 mCi to treat a dog scheduled for a 9:00 am appointment on
                Friday. How much 153Sm will Dr. Lattimer have when his patient arrives? Will he have
                enough to give the prescribed dose?




3.   The linear attenuation coefficient (μ) of the 103 keV 153Sm photon is 0.15 cm-1 in bone.
     a.      What is the half-value layer (HVL) of this photon in bone?




     b.      How many cm of bone are required to reduce the initial intensity (I0) of these photons
             by 90% (i.e., I = 10% of I0)?




     c. Approximately how many half-value layers (HVLs) is this?




4.   The range of a 6.8 MeV alpha particle in soft tissue is 34.9 µm.



     a.      What is the LET (in keV/μm) of this alpha particle in tissue?
     b.    Estimate the LET (in keV/μm) of a 6.8 MeV proton (i.e., 11H+1) in tissue.




5.   TRUE/FALSE



     _____ a.      The range of a 62 keV tungsten characteristic x-ray is longer than the range of a
                   5 MeV alpha particle in soft tissue.



                   111
     _____ b.        In is produced by proton irradiation of 111Cd using a cyclotron. Therefore, it is
                   generally used for diagnostic imaging.


     _____ c.      Bremsstrahlung radiation emitted from an x-ray tube is always monoenergetic.
     _____ d.        Pierre and Marie Curie shared the 1903 Nobel Prize in Physics with Henri
                     Becquerel for the discovery of natural radioactivity.


     _____ e.        As the energy of a given type of charged particle increases, its range in matter
                     decreases.


     _____ f.        Alpha particles emitted during radioactive decay are always observed at discrete
                     energies, while beta particles (β- and β+) resulting from radioactive decay are
                     always observed as a continuous energy spectrum.


     _____ g.        When a high-energy charged particle (e.g., a 15 MeV LINAC electron) first
                     collides with an atom in an absorbing medium, it usually transfers only a tiny
                     fraction of its kinetic energy to that atom.


     _____ h.        Without knowing the mechanism of emission, it is impossible to distinguish
                     Auger and conversion electrons using a conventional radiation detector.


6.   Rank the following forms of ionizing radiation in order of increasing LET. (Fill in the blanks: rank
     the lowest LET radiation number 1 and the highest number 6.)


     a.      140 keV gamma ray                         _____
     b.      5 MeV electron                   _____
     c.      5 MeV proton                              _____
     d.      500 keV positron                          _____
     e.      500 keV alpha particle           _____
     f.      5 MeV alpha particle                      _____


7.   In terms of radiation biology effects, the most important mechanism by which photons interact
     with soft tissue is


     a.      Compton scattering.
     b.      the photoelectric effect.
     c.      transfer of an average of 60 eV by collision with an atom.
     d.      pair production.
      e.      none of the above.


8.    If you were to absorb 67 calories of energy (equal to 1.75 × 1021 eV), which process is most likely
      to ruin your whole day?


      a.      Being lifted overhead by a circus strongman.
      b.      Drinking one sip of hot coffee.
      c.      Absorbing a lethal dose of ionizing radiation.
      d.      Having your body temperature increase to 37.002 °C.


9.    The range of charged particles in matter is, by definition, always


      a.      approximately 4 cm.
      b.      impossible to estimate.
      c.      infinite.
      d.      finite.
      e.      none of the above.


10.   Anytime a nucleus is capable of emitting a gamma ray,


      a.      it must be undergoing isomeric transition.
      b.      it must have been left in an excited state following alpha or beta minus decay.
      c.      an orbital electron could be ejected as an internal conversion electron instead.
      d.      all of the above.
      e.      none of the above.
11.   Briefly define, identify, or describe.


      a.      Ionizing radiation




      b.      Radioactivity, or radioactive decay




      c.      LET




      d.      Wilhelm Conrad Röntgen




      e.      Photoelectric effect
      f.      The major decay modes of proton rich radionuclides




      g.      Half-life of a radionuclide
                                 Radiopharmaceuticals in Nuclear Medicine
                                           Fall 2010, Exam 2

1.   Identify which of the following SPECT and PET radiopharmaceuticals are currently used for
     assessment of myocardial (heart muscle blood flow) [more than one answer is possible].
               13                                       82
     a)          N-ammonia                         e)     Rb+
               99m                                      201
     b)           Tc-ECD                           f)      Thallous chloride
               99m                                      99m
     c)           Tc-HMPAO                         g)      Tc-DISIDA
               99m                                      99m
     d)           Tc-sestamibi                     h)      Tc-tetrofosmin
                                                        18
                                                   g)     F-FDG
     99m
2.        Tc-S-colloid is used for gastric emptying and lymph node imaging studies in patients.

     a)        What is a colloid?




               99m
     b)               Tc-S-colloid is considered

               i.          very stable
               ii.         moderately stable
               iii.        not very stable

     c)        The size of 99mTc-S-colloid is considerably smaller in diameter than 99mTc-MAA particles
               (True or False).

3.   The physical properties of 18F are:

     a)        half-life _______
     b)        mode of decay__________________
     c)        energy of photons emitted resulting from the decay of 18F.

4.   a) Explain (a sketch may help) how the glomerular filtration (GF) process occurs in the kidneys
     for clearance of some radiopharmaceuticals.
     b)      Radiopharmaceuticals that are cleared from the blood primarily via the GF route are:

             i)        small and hydrophilic
             ii)       small and hydrophobic
             iii)      large (> 10 K Daltons) and hydrophobic
             iv)       large (> 10 K Daltons) and hydrophilic

5.   The mechanism of uptake of some radiopharmaceuticals occurs by passive diffusion of the
     radiopharmaceutical from the blood into the tissue/cells/organ. Describe what “Passive
     Diffusion” is and provide two examples of radiopharmaceuticals that localize by the process.




6.   Define or describe the following terms.

     a)      Blood Brain Barrier




             18
     b)        F-FDG




     c)      First pass “Extraction Efficiency” of a radiopharmaceutical from the blood by a tissue.




     d)      Blood plasma
        18
7.       F-fluoride is used for imaging _____________________________________

8.      What is the mechanism of trapping of 99mTc-sestamibi in the cells where it localizes?




9.      a)        The overall charge on 99mTc-mebrofenin is

                  i)      -2
                  ii)     -1
                  iii)    0
                  iv)     +1

        b)        The cell in the liver involved in clearance of 99mTc-mebrofenin from the blood is

                  ________________________________________________.

10.     True-False

        99m
___a.        TcO is primarily cleared from the body by the tubular secretion process in the kidneys.

        18
___b.    F-FDG localizes in the brain and heart muscle via a receptor mediated pathway on the cell
        membranes responsible for transport of unlabeled glucose molecules from the blood.
                         Introduction to Radiation Biology – Exam III
          November 11, 2010                                                                 Dr. Lattimer

For each of the following questions choose the one best answer from those provided at the bottom of
each page. Answers may be used once, more than once or not at all. Please put answers in the left
hand margin next to the question.

1. Free radicals reacting with DNA are the most common source of damage to the DNA by radiation.
   Which of the choices is the compound or element which is the most frequent source of these free
   radicals?

2. DNA is one of the most complex molecules known. Which of the choices represents the subunit of
   the cellular DNA which can be seen by light microscopy during cellular division?

3. Nearly all the DNA in the cell is located in the nucleus of the cell but there is a small amount of it
   which is found outside the nucleus. Where is this small amount of DNA found?

4. Radiation induced injury to the DNA can result in numerous types of injury to the DNA. Which of the
   choices is the type of injury which is most easily repaired by intranuclear repair mechanisms?

5. What category of DNA damage is that which could be enhanced or made more lethal by
   hyperthermia?

6. Acentric fragments are examples of choromosomal aberrations arising from what type of damage?

7. What type of DNA injury which could result in loss of large amounts of DNA from the nucleus is
   usually efficiently repaired by intranuclear repair mechanisms?

8. What type of DNA injury is usually accurately repaired only during S-phase of the cell cycle?

9. The initial straight portion of the cell survival curve seen at low doses is due to what type of DNA
   damage?

Choices

a.        Lethal damage                   f.      Protien                  m.       Base deletion
b.        Potentially Lethal Damage       g.      Chromosome               n.       Single strand break
c.        Sublethal Damage                h.      Chromatid                o.       Double strand break
d.        Oxygen                          i.      Gene                     p.       mitosis
e.        Water                           j.      Golgi Body               q.       G1-phase
f.        Nitrogen                        k.      Mitochondria             r.       S-phase
e.        DNA                             l.      Nucleus                  q.       G2-phase
10. Repair of DNA injury is generally considered to have the greatest effect during which phase of the
    cell cycle?

11. Repair of DNA injury is has the least effect during which phase of the cell cycle?

12. Which of the choices can improve the efficiency of DNA repair for a given total dose to the DNA?

13. In some instances the effect of DNA repair is also enhanced by what other process.

14. Reestablishment of the normal cell cycle phase proportions of a cycling cell population following
    preferential killing of some phase of the cycle is referred to as what?

15. Cell populations with different cell cycle kinetics exhibit different apparent radiation responses.
    Bone marrow stem cells are examples of which type of cell population according to Rubin and
    Cassarett?

16. Cells with have the potential to differentiate into other cell types to aid and promote repair of tissue
    radiation injury are known as what types of cells.

17. Cells such a pneumocytes which are differentiated cells which have the ability to reproduce
    themselves are members of what type of cell population according to Michaelowski?

18. Cell lines which must survive for a tissue and sometimes the organism to survive are called what?

19. Cell lines which typically exhibit strong repair capabilities are typically what type of cells?

20. Profound hypoxia at the cellular level is a potent promoter of what process?

21. In Vitro assays done with cell culture are typically examples of what type of cellular assay?

22. In Vivo assays involving implanting tissue from one animal to another are what type of assay?



Choices:

a. Mitosis                        h.      Repopulation                       o.      Lethality
b. G1-phase                       i.      Vegetative intermitotic            p.      Transplantation
c. G2-phase                       j       Differentiating intermitotic       q.      Clonogenic
d. S-phase                        k.      Multipotential connective          r.      Functional
e. Reassortment                   l.      Reverting post mitotic             s.      Flexible cells
f.   Repair                       m.      Fixed post mitotic                 t.      Critical cells
g. Reoxygenation                  n.      In Situ                            u.      Hierarchical
23. Erythema, edema and moist desquamation are examples of what type of tissue response to
    radiation injury.

24. Replacement of cells in a radiation field by cells of another type is an example of what type of tissue
    response?

25. Tissues for which the critical cell lines have long cell cycle times are referred to as what type of
    tissue?

26. Bone marrow and intestinal epithelium are considered to be what types of tissue with regards to
    radiation injury?

27. Hair loss and atrophy of fat in a radiation field are examples of what type of tissue response?

28. The cellular kinetics factor which favors recovery of a tissue following radiation exposure would be
    what?

29. Which of the cell types listed is considered to be most resistant to radiation injury?

30. Which of the cell types listed is considered to be the most sensitive to radiation injury?

31. Which of the cell types listed is responsible for recovery of skin following radiation injury?

32. Which of the cell types listed is considered to be the dose limiting cell in the GI tract?

33. Which of the reproductive cells listed is the most resistant to killing by radiation?

34. Which of the cell types listed below is especially susceptible to injury in teenagers and very young
    children?



Choices:

a. Early responding                       h.       Lymphocyte               o.       Hepatocytes
b. Late responding                        i.       Pneumocytes              p.       Oocyte
c. Acute reaction                         j.       Macrophage               q.       Crypt cells
d. Chronic reaction                       k.       Basal Cells              r.       Bone marrow cell
e. Cellular Growth fraction               l.       Epithelial cells         s.       Cartilage cells
f.   Cellular Loss fraction               m.       Germinal cells           t.       Erythrocyte
g. Blast cells                            n.       Mucous cells             u.       Sperm cells
35. Which particulate radiation is of greatest concern with regards to whole body radiation exposure?

36. Which of the particulate radiations will result in the highest local dose equivalent to a tissue
    concentrating it?

37. The prodromal stage of a radiation syndrome is an example of what type of response to whole body
    irradiation?

38. The Bone Marrow Syndrome usually causes death through which process?

39. The GI Syndrome usually causes death through what process?

40. Death is virtually a certainty after what dose of radiation to the whole body?

41. How long following a whole body irradiation would the Bone Marrow Syndrome reach a manifest
    illness stage?

42. The period of organogenesis resulting in extreme organ system sensitivities to irradiation lasts
    approximately how long in humans?

43. In the human fetus the central nervous system is at particular risk for approximately how many
    weeks of the gestation?

44. Approximately how long after exposure to an antigen will a whole body irradiation dose of 1.0 Gy
    not blunt the immune response to the body to that antigen.

45. Which type of radiation would be of particular threat to a developing embryo?

46. Blunting of the immune response to antigens has been demonstrated to occur in some experiments
    at doses as low as?

47. In humans, a whole body radiation dose at which a bone marrow transplant would be expected to
    improve survival would be?

Choices:

a. photons                       i.       3 weeks                  q.      5 gray
b. neutrons                      j.       6 weeks                  r.      10 gray
c. alpha particles               k.       18 weeks                 s.      acute
d. Beta particles                l.       39 weeks                 t.      late
e. 1 day                         m.       0.1 gray                 u.      infection
f.   4 days                      n.      0.5 gray                 v.       anemia
g. 1 week                        o.      1.0 gray                 w.       starvation
h. 2 weeks                       p.      3.0 gray                 x.       dehydration



48. For the induction of cancer several criteria have to be satisfied. One of those criteria is up-
    regulation of positive growth promoting factors within the cell. Which of these results in such a
    positive growth promoting factor?

49. Cells which suffer a DNA mutation which causes them to die when they try to reproduce and are
    removed from the cycling pool at the G1-S interface die by what mechanism?

50. Genes which encode for the repair of DNA damage are part of what general group of genes?

51. No matter the mechanism by which it occurs, tumor cells must escape certain controls on their
    proliferation. What is the most fundamental control lost by any neoplastic growth?

52. Loss or reduced function of which general group of genes will promote the development of
    neoplastic disease.

53. In order for a mutated cell to develop into a cancer it must retain what capability.

54. Tumor cell populations possess what characteristic which is very different from the cell population
    which they arise from?

55. What response to irradiation of a large neoplastic growth is virtually never seen in normal tissues?

56. Failure to control a tumor using radiation is due to what response of the tumor to the radiation
    injury?

57. Radiation injury may result in either tumor cells or normal cells becoming part of the cycling cell
    population where they were not before. This may happen for a variety of reasons. What is the term
    which is used to indicate this process?

58. The use of multiple radiation treatments (fractions) is used with photon radiation principally due to
    what process that occurs in cell populations following irradiation?

59. Using smaller fractions of radiation favors the survival of what type of tissues?

Choices:

a. Late responding               i.      mutagenic activity                q.       Contact inhibition
b. Early responding              j.      clonogenic activity               r.       Cellular adhesion
c. Acute injury                  k.      functional activity               s.       Apoptosis
d. Reoxygenation                l.       Proto-oncogenes                 t.       Mitotic linked death
e. Reassortment                 m.       DNA stability genes             u.       Immunological attack
f.   Repair                     n.       Tumor suppressor genes          v.       revascularization
g. Repopulation                 o.       Phenotypic diversity            w.       metastasis
h. Recruitment                  p.       Genetic diversity               x.       Hypoxia



60. Use of High LET radiation for treatment of cancer would be most valuable for treatment of tumors
    have large numbers of cells exhibiting what characteristic?

61. High LET radiation also is a powerful suppressor of what process?

62. Chemotherapeutic agents in combination with radiation are most likely to have the most dramatic
    effect on what types of tissue?

63. Drugs which improve blood flow to a tumor would promote what process?

64. In general, the radioprotectant Amiphostine enhances survival of what types of tissues?

65. High energy protons and electrons are considered to be what type of radiation?

66. Hyperthermia could be used to enhance cell killing in tumors if it could be limited to the tumor
    because it inhibits what process?

67. Administration of what type of radiation therapy can result in very high doses of radiation to a
    tumor with minimal to very little dose to the surrounding normal tissues?

66. Hyperthermia is synergistic with radiation because its effect is not blunted by what condition?

67. Reducing the normal tissue dose to ½ of the tumor dose should theoretically reduce the normal
    tissue effects relative to the tumor by a factor of how much?

68. If a dose of 1.5 gray kills 50% of the cells in a population each time it is given, how many doses
    would it require to reduce the number of cells in the population by >99% assuming no repopulation?

69. With regards to carcinogensis due to low dose, low dose rate radiation exposure, doubling the dose
    increases the probability of a radiation induce neoplasm by what factor?

70. The radioprotective effect of hypoxia occurs principally below how many mmHg of oxygen tension?

71. High LET radiation would have the most profound effect on cells in what part of the cell cycle?

72. What type of radiation therapy would be best suited to treating a small deep seated brain tumor
    located next to the visual cortex of the brain?
Choices

   a. 1    i.   Repair                  q.   teletherapy
   b. 2    j.   Reoxyengenation         p.   brachytherapy
   c. 3    k.   Reassortment            q.   neutron therapy
   d. 4    l.   Repopulation            r.   proton therapy
   e. 5    m.   Early responding        s.   High LET
   f. 7    n.   Late responding         t.   Low LET
   g. 10   o.   hypoxia                 u.   Mitosis
   h. 20   p.   heterogenous genotype   v.   S-phase
                                            Name___________________________________

                             Introductory Radiation Biology
                                    Final Exam, 2010

1.   A radiation worker received a whole body dose of 100 mrads from fast neutrons
     (QF = 20) as a result of an accident.

     a.     Calculate the Equivalent Dose (in mrem units) this worker received.




     b.     The Equivalent Dose in mSv units is __________ mSv.

     c.     The Absorbed Dose in Gy units is ________________Gy

2.   a) According to the BEIR and UNSCEAR reports, it has been estimated that
     approximately ____________________ radiation induced cancer deaths will occur in a
     population of 1 million people receiving a whole body radiation dose (from gamma-rays)
     of 1 rem each.

     b) Using this risk estimate and assuming the linear-non-threshold extrapolation
     approach, calculate the number of cancer deaths that would be produced by exposure
     of a group of 20,000 people to a whole body dose (from gamma-rays) of 50 rem each
     (Show work)




     c) According to current epidemiology studies, approximately the percent of our
     population who will die from “spontaneous” cancers is __________________. Thus, in
     this group of 20,000 persons, approximately ______________ people are expected to
     die from cancer from “spontaneous” cancers (i.e., assuming they do not receive the 50
     rem exposure as stated in part b of this question].
3.   Briefly define or describe (can use sketches when applicable)

     a) Linear, Non-threshold Extrapolation method




     b) Oxygen Effect




     c) Free Radical




     d) Double-strand breaks in the DNA




     c) At least two sources of “Natural” background radiation




4.   Radiation exposure of animals and humans will produce “Non-Stochastic Effects” at
     higher radiation doses.

     a) Describe what is meant by the term “Non-Stochastic” and give an example of a
     property of “Non-stochastic Effects” that will differentiate them from “Stochastic
     Effects”.
     b) Give two examples of “Non-Stochastic Effects” that are be produced by ionizing
     radiation in animals and humans




     c) Give two examples of “Stochastic Effects” that are produced by ionizing radiation in
     animals and humans.




5.   a) Sketch what a “Cell Survival Curve” will look like if human kidney cells are irradiated
     at a high dose rate, under 150 mrem Hg O2 with 1 MeV gamma rays. Label the X-axis
     and Y-axis with appropriate units.




     b) If these cells receive a radiation dose to produce a “D5”, the percent of the cells
     remain alive (i.e., survive) at the D5 dose is ____________%.

6.   Explain why epidemiology studies are able to demonstrate radiation exposure to
     humans, will produce a “statistically” measurable increase in thyroid CA incidence at
     lower doses (e.g., in the 10-30 rad to the thyroid) compared to radiation induced by lung
     cancers (e.g., usually in the range of 50-100 rad doses to lungs).
7.   a) Briefly explain why 131I-iodide, present in the fallout from an A-Bomb explosion, will
     be taken up by the thyroid gland of humans following ingestion of food or liquids
     contaminated with 131I-iodide.




     c) The major fraction of the radiation dose to the thyroid gland from 131I located in
     thyroid tissue is from the ____________ emitted during the decay of 131I.

            a. beta particles
            b. gamma-rays
            c. alpha particles.

     b) Repeated epidemiology studies demonstrate that human adult patients treated for
     hyperthyroid disease in 5-10 mCi of 131I-soduim iodide (producing an approximately 50-
     100 Gy dose to the thyroid gland) results in a significant increase in thyroid cancer in the
     patients later in life, when compared to patients with hyperthyroid disease treated
     surgically (i.e., not administered 131-I-sodium iodide (TRUE or FALSE).

8.   a) List three types of effects produced by excessive in utero radiation of the embryo or
     fetus in the first trimester of humans or mammals.




     b) The approximate in utero dose of gamma or x-radiation dose to the fetus in the first
     trimester that will first produce a significant increase of serious congenital
     malformations in newborn babies, relative to the spontaneous (background) rate of
     congenital malformations in the U.S. population is approximately 15 rads
     (TRUE or FALSE).
c) The “spontaneous” (background) rate of babies born with serious congenital malformation
in the U.S. is approximately:

             i) 2%    ii) 5%    iii) 15%     iv) 25%

9.    TRUE-FALSE

___   a)     The rate of production of radiation-induced hereditary effects (i.e., # of genetic
             defects/rem) is currently estimated to be about the same, or perhaps lower,
             than the rate of production of radiation-induced cancer deaths (i.e., # cancer
             deaths/rem) in the U.S. population.

___   b)     The base excision repair process is more effective in repairing DNA damage to
             is exposed to 1 MeV protons compared to when human cells irradiate with 1
             MeV gamma-rays.

___   c)     Thyroid cancer is more readily induced (i.e., # cancers induced/rad) by ionizing
             radiation (e.g., 131I) in young children compared to adults.

___   d)     There are no unique types of cancers in humans induced by ionizing radiation,
             i.e., they all also occur “spontaneously” in the U.S. population.

___   e)     The epidemiology studies of A-Bomb survivors have been able to demonstrate a
             significant increase in some radiation-induced cancers in this population. In
             contrast, epidemiology studies in this A-Bomb survivor population have not been
             able to demonstrate an increase in radiation-induced genetic effects.

___   f)     There are no unique types of congenital malformations found in human babies
             induced by ionizing radiation, i.e., all congenital malformations induced by
             ionizing radiation also occur “spontaneously” in the U.S. population.
                     INTRODUCTORY RADIATION BIOLOGY 328


                     FINAL EXAM QUESTIONS 2010—Michael R. Lewis, Ph.D.




1.   Rank the following ionizing radiations in order of increasing ability to penetrate soft
     tissue (i.e., beginning with the smallest range or depth of penetration; e.g., a < b < c < d,
     but please note that this may or may not be the correct answer!).


     a.   62 keV x-ray
     b.   8 MeV alpha particle
     c.   635 keV positron
     d.   15 MeV electron


2.   Promethium-149 (14961Pm; T1/2 = 53 h) decays to 14962Sm (stable). In 96.9% of events, 149Pm
     decays to the ground state of 149Sm, while in 3.1% of events, it decays to an excited state of
     149
        Sm that lies 286 keV above the ground state.



     a.      Sketch a decay scheme that is consistent with this information.
b. True or False (circle one): 149Pm decay can be imaged using a gamma camera.
c.     True or False (circle one): 149Pm is potentially useful for radionuclide therapy.
d.     In his laboratory, Dr. Mike Lewis has been evaluating 149Pm radiopharmaceuticals for
       cancer. He has planned an experiment for 1 pm on Wednesday and has ordered
       delivery of 100 mCi of 149Pm produced at the MU Research Reactor (MURR). Assuming
       that no 149Pm is lost during purification and processing, how much 149Pm has to be
       present at the end of irradiation at 8 am on Monday, in order for MURR to fill Dr. Lewis’s
       order?
3.   Briefly define or describe (no more than 1-2 sentences):



     a.      The type of radiation that most nuclear medicine (i.e., scintillation or Anger) cameras
             detect




     b.      Mean free path




     c.      Henri Becquerel




     d.      The predominant mode of 18F decay
e.   The most biologically relevant mechanism by which ionizing photons interact with soft
     tissue (HINT: predominates in the energy range of 100 keV to 10 MeV)




f.   An element discovered by Pierre and Madam Marie Curie




g.   Wilhelm Conrad Röntgen




h.   Ionizing radiation
      i.      LET




TRUE/FALSE



4.    _____A 4 MeV x-ray photon will have lower LET and cause less biological damage over its track
      in the body than a 4 MeV alpha particle.



5.    _____99mTc emits a gamma ray during its decay, which makes it highly useful for cancer therapy.



6.    _____Radionuclides produced by charged particle accelerators generally decay by electron
      capture and/or positron emission, making them potentially useful for diagnostic imaging.



MULTIPLE CHOICE



7.    Imaging using Na131I is often performed for

      a.      diagnostic reasons only.
      b.      detecting osteosarcoma, metastatic prostate cancer, and other bone tumors.
      c.      planning radionuclide therapy of differentiated thyroid cancer.
      d.      all of the above.
      e.      none of the above.


8.    In what tissues would you expect high accumulations of [18F]Fluorodeoxyglucose (18F-FDG)?

      a.      brain
      b.      heart
      c.      tumors
      d.      all of the above
e.   none of the above
9.    In order to determine whether a patient with skeletal metastases from prostate cancer is a good
      candidate to use 153Sm-EDTMP (QuadraMet™) for pain relief, the appropriate diagnostic test is

      a.     imaging with Na131I.
      b.     imaging with 11C-Raclopride.
      c.     imaging with 99mTc-MDP.
      d.     imaging with 18F-FDG.
      e.     determining how high the patient can bounce on a trampoline.


10.   In nuclear medicine, the emerging “gold standard” for diagnosing and/or determining the extent
      of several types of cancer is
             153
      a.        Sm-EDTMP.
      b.     Na131I.
             201
      c.        TlCl.
             18
      d.       F-FDG.
             99m
      e.         Tc-Sestamibi.
Final Examination questions for Radiation Biology 2010 – Dr. Lattimer

1.      What is the principal means by which neutrons and other high LET radiation damage the DNA?

        a.      Direct ionization of a portion of the DNA molecule
        b.      Indirect damage by free radical species arising from interaction with oxygen
        c.      Indirect damage by free radical species arising from interaction with water
        d.      Direct collisional interaction with atoms in the molecule disrupting chemical bonds
        e.      Secondary ionization of the molecule by recoil electrons from collision with water

2.      Which of the following will result in the greatest improvement in repair of ionizing radiation
        induced DNA damage?

        a.      Long (weeks to months) period of time between radiation exposures.
        b.      Irradiation occurring during the G1 phase of the cell cycle
        c.      Very low dose rate
        d.      Low total dose
        e.      Irradiation with low energy photons

3.      The presence of a broad shoulder on the cell survival curve for ionizing radiation injury to a
        population of cells is and indication of which of the following?

        a.      The individual cells have long cell cycle times
        b.      The individual cells have good repopulation (clonogenic) potential
        c.      The individual cells have different sensitivities to radiation injury
        d.      The individual cells have good damage repair capabilities
        e.      The individual cells are genetically and phenotypically diverse

4.      Cell death principally occurs when cells in their reproductive cycle reach one of two points in the
        cell cycle. What are these two points which we talked about in class?

        a.      S-G2 phase interface and Mitosis
        b.      Mitosis and G1
        c.      G1-S phase interface and S-G2 phase interface
        d.      G1 and S phases
        e.      G1-S phase interface and Mitosis

5.      Which of the following groups of cell types represent all F-type cell population according to the
        Michaelowski classification.

        a.      Intestinal crypt cells, Basal cells, bone marrow stem cells
        b.      Plasma cells, endothelial cells, hepatocytes
        c.      neurons, fibroblasts, Basal cells
        d.      skin epithelial cells, erythrocytes, oral mucosal cells
        e.      Bone osteocytes, intestinal crypt cells, oocytes
6.   The cell survival curve reflects three different segments which refer to three different types of
     DNA injury, they are?

     a.      Repairable injury, Potentially repairable injury and no injury
     b.      Non-repairable injury, lethal injury and non-lethal injury
     c.      Single strand breaks, Double strand breaks and base pair deletions
     d.      Non repairable single hit injury, repairable injury and non-repairable multi-hit injury
     e.      Single hit injury, double hit injury, multiple (greater than 2 hit) injury

7.   Given the survival curve depicted what type of assay was performed

     a.      Clonogenic

     b.      Lethality

     c.      Transplantation

     d.      In Vitro

     e.      In Situ
8.    Which of the following would not be expected to affect the response of a tissue to a radiation
      exposure?

      a.      The volume of tissue irradiated.
      b.      The presence of hypoxic cells in the tissue
      c.      The type of radiation
      d.      The dose rate.
      e.      The source of the radiation

9.    Which organ system is at particular risk in humans relative to other species.

      a.      Intestinal tract
      b.      Bone marrow
      c.      Central nervous system
      d.      Skin
      e.      Lungs

10.   Low doses of radiation (0.1-0.5Gy) to a fetus probably have the greatest mutagenic potential
      during what period of gestation in humans?

      a.      0-2 weeks
      b.      2-6 weeks
      c.      6-10 weeks
      d.      10-14 weeks
      e.      35-39 weeks

11.   With respect to the potential for carcinogenesis and increased risk for neoplastic disease
      induction, doubling the whole body dose to an individual above the accepted maximum
      allowable dose would increase the probability of cancer induction by what factor.

      a.      2
      b.      4
      c.      8
      d.      10
      e.      20



12.   When doing radiation therapy or any time when radiation is administered or received for any
      reason, fractionating the dose is beneficial. Which of the following is the principal reason that
      this is done in radiation therapy?

      a.      Decrease early responding tissue effects
      b.      Decrease late responding tissue effects
      c.      Increase early responding tissue effects
      d.      Increase late responding tissue effects.
      e.      b and c above



13.   When fractionating dose, increasing the dose per fraction while keeping the total dose and the
      total time over which the dose is administered constant, what is the generally accepted effect of
      reducing the dose per fraction and increasing the number of fractions?

      a.      Increased late effects and decreased scarring of the tissue
      b.      Decreased late effects and decreased scarring of the tissue
      c.      Increased early effects and decreased scarring of the tissue
      d.      Decreased early effects and increased scarring of the tissue
      e.      Increased early effects and increased scarring of the tissue

				
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