Introductory Radiation BiologyExam I, 2011

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

(NO WORK, NO CREDIT!!!)

1. There is only one NBC affiliate commercial newsroom in the world associated with a university, the MU School of Journalism’s KOMU-TV 8. The station’s broadcast frequency is 183 MHz (1.83 × 108 s-1). What is the energy (in eV) of the “J-School’s” TV news photons?

2. When Dr. Lewis was a postdoctoral fellow at Washington University in St. Louis, he used a cyclotron to produce 66

31Ga (T1/2 = 9.5 h) for imaging research. 6631Ga decays exclusively to 66

30Zn (stable), with a decay energy of 4.15 MeV. In 50% of events, 66

31Ga decays to the ground state of 66

30Zn, with emission of a charged particle. In 6% of events, 6631Ga decays to an excited state 3.23

MeV above the ground state of 6630Zn, with emission of a charged particle. This excited state de-

excites in less than 1 ns to the ground state of 6630Zn.

a. Sketch a decay scheme that is consistent with this information.

b. In the other 44% of events, 6631Ga decays by

1. isomeric transition.2. electron capture.3. spontaneous fission.4. bacterial decomposition.

c. Dr. Lewis worked with Professor Mark Green of Purdue University to image tumor folate receptors, using the radiopharmaceutical 66Ga-DF-folate. At the end of a cyclotron run, it took Dr. Lewis 2.5 hours to purify 66Ga from the target, and it took Dr. Green 1 hour to synthesize 66Ga-DF-folate for injection. A subject was imaged with 4.5 mCi of 66Ga-DF-folate 25 hours later. Assuming no loss of 66Ga during radionuclide purification and radiopharmaceutical synthesis, how much 66Ga did Dr. Lewis need to produce on the cyclotron to accomplish the imaging procedure?

d. List all the types of emissions (i.e., photons and particles) that will occur during the decay of 66Ga.

3. The linear attenuation coefficient (μ) of the 3.23 MeV 66Ga photon in lead is 0.395 cm-1.

a. What is the half-value layer (HVL) of this photon in lead?

b. How many cm of lead are required to reduce the initial intensity (I 0) of these photons to a safe level, that is, by 90% (i.e., It = 10% of I0)?

c. The thickness of the lead bunker in which Dr. Lewis purifies the 66Ga is exactly 5 cm. Is he safe from 90% of these photons, or does he need to add more lead to keep from getting fried by ionizing radiation?

4. At the University of Washington, Dr. Ethan Balkin, one of Dr. Lewis’s former graduate students, is working with 211At (T1/2 = 7.2 h) to treat lymphoma. The LET of the 6.8 MeV 211At alpha particle (i.e., 4

2He+2) is 195 keV/μm.

a. What is the range of this alpha particle in soft tissue?

b. Estimate the LET (in keV/μm) of a 6.8 MeV proton (i.e., 11H+1) in soft tissue.

5. TRUE/FALSE

_____ a. The wavelength of a 100 keV x-ray photon is longer than the wavelength of a 5 eV ultraviolet photon.

_____ b. 131I is produced by spontaneous fission of 235U, following neutron irradiation in a nuclear reactor. Therefore, it is generally used for radiation therapy.

_____ c. Alpha particles are emitted over a wide spectrum of energies, while beta particles (β- and β+) are always monoenergetic.

_____ d. Marie Curie won the 1911 Nobel Prize in Chemistry for the discovery of “uranium rays.”

_____ e. A 1 MeV gamma ray is more likely to interact with soft tissue by Compton scattering than by the photoelectric effect.

_____ f. The ionization density along the linear track of a 1 MeV electron is higher than that along the linear track of a 1 MeV alpha particle.

_____ g. The range of 500 keV photons in soft tissue can vary from 0 to , while 500 keV beta minus particles are expected to have approximately the same, relatively short range in soft tissue.

_____ h. As the energy of a given type of charged particle increases, its linear energy transfer (LET) decreases.

_____ i. The minimum energy required to ionize an atom or molecule is approximately 10 eV.

6. Rank the following forms of ionizing radiation in order of increasing ability to penetrate soft tissue (i.e., range). (Fill in the blanks: rank the least penetrating radiation number 1 and the most penetrating number 6.)

a. 1 MeV alpha particle _____b. 1 MeV proton _____c. 2 MeV alpha particle _____d. 1 MeV electron _____e. 1 MeV gamma ray _____f. 2 MeV positron _____

7. The atomic number of a daughter nuclide is the same as that of the parent radionuclide following

a. alpha decay.b. beta minus decay.c. positron decay.d. electron capture.e. isomeric transition.

8. By now you might need a little extra energy to finish this exam, so you reach for your thermos and take a sip of hot coffee. It gives you enough energy to

a. boost your IQ by 50 points and ace the test.b. raise your blood pressure by 50 points and cause a heart attack.c. kill you if it were ionizing radiation instead.d. make you glow in the dark.

9. Which of the following is considered high LET radiation?

a. a 15 MeV LINAC electronb. a 62 keV tungsten characteristic x-rayc. a 5 MeV alpha particled. a 573 keV beta minus particlee. all of the above

10. When positrons combine with electrons in matter at the end of their path, what happens?

a. They undergo an annihilation reaction.b. They create a particle with twice the mass of an electron but no charge.c. Two 511 keV (0.511 MeV) photons are emitted in opposite directions.d. Both (a) and (c) above.e. Nothing whatsoever.

11. When a radionuclide undergoes beta minus decay, which of the following must occur?

a. emission of gamma raysb. creation of an antineutrinoc. emission of Auger electronsd. internal conversione. emission of a positron

12. Briefly define, identify, or describe.

a. Wilhelm Conrad Röntgen

b. Ionizing radiation

c. The atomic mode of energy loss that competes with gamma ray emission

d. LET

e. Radioactive decay, or radioactivity

g. Mean free path

Name_____________________________

INTRODUCTORY RADIATION BIOLOGYEXAM II – 2011

1. Assume a radiation worker involved in addressing the tsunami induced Dai-Ichi power reactor event in Fukushima, Japan received a whole body dose of radiation calculated to be approximately 100 rem. It is estimated that the worker received a 70 rem dose from fast neutrons and a 30 rem dose from high energy gamma-rays. Assuming the QF for fast neutrons is 10;

a. Calculate the radiation absorbed dose (in rads) that this worker received from the gamma-ray exposures.

b. What is the rad dose you calculated above expressed in units of Gy?

c. Calculate the radiation absorbed dose (in rad units) this worker received from the fast neutron exposure.

2. If the film badge worn by a radiation worker indicated that he/she received 5 mSv last month, this worker received ______________ mRems.

3. The type of damage to the DNA that has been shown to have an ionizing radiation dose-response relationship that most closely follows cell killing as a function of radiation dose is/are:

a. single strand DNA breaksb. damage to DNA basesc. double strand DNA breaksd. DNA-DNA cross-links

4. The attached semi-log paper figure is a plot of two cell survival curves (Curve A and Curve B). Answer the following questions relating to these survival curves. Assume both survival curves were generated by irradiating human kidney cells that were irradiated under atmospheric O2 conditions using either 2 MeV protons or 250 KVp x-rays at a high dose rate.

a. The DO for Curve A is ___________________.

b. The DO for Curve B is (higher than, approximately the same as, lower than) the DO for Curve A.

c. The extrapolation number for Curve A is __________________

d. The sensitivity (i.e., k) for Curve A is __________ rad-1.

e. Identify which curve (A or B) would have been generated by irradiation of the cells with 250 KVp X-rays.

f. The D1 for Curve B is __________ rads

5. Using the double strand break (dsb) and single strand break (ssb) models, describe how irreparable damage to induce a permanent genetic mutation on double strand DNA can occur (sketches will be helpful by a:

a. One-hit process

b. two-hit mechanism

6. Briefly explain why a lower fraction of human cells that are irradiated at a high dose rate (under atmospheric O2) with one single 200 rad dose in 5 minutes of 1MeV gamma-rays will die than if the 200 rad total dose was delivered in two separate 100 rad doses delivered in 5 minutes and separated with a one day interval between the first 100 rad dose and the second 100 rad dose.

7. Briefly explain why fast neutrons are considered a form of High LET radiation, even though they penetrate quite far through mammalian tissues.

8. Briefly define or explain

a. Following damage of a DNA base (i.e., A, T, C or G) by UV or ionizing radiation, one or more breaks in a strand of the DNA will occur during the repair

process. Briefly explain the process by which this strand break occurs.

b. OER as a function of p02. A graph will be helpful.

c. AT-cells

d. The Roentgen unit

e. RBE

f. Indirect Effect

g. Elkind Repair

h. Why do you a priori predict that the H-atom (i.e., H•) is a free radical?

i. Explain why repair of double stranded DNA organisms (e.g., human cells) are much more efficient in repairing X-ray or UV radiation damage than single stranded DNA or RNA organisms (e.g., some viruses).

9. True-False

___ a. Ionizing radiation can damage DNA and cause cell killing by the Indirect and Direct Effect. When human cells are irradiated with 4 MeV alpha

particles, it can be estimated that more than 50% of the damage to the DNA in these cells is related to the “Indirect Effect”.

___ b. Repair of DNA by the Nucleotide Excision Repair (NER) process is more effective in repairing UV damage than repairing the damage inflicted by X-rays.

___ c. The “superoxide” anion is considered to be a free radical.

___ d. A single strand break (ssb) of the DNA in mammalian cells is considered to be type of damage that is usually repairable.

___ e. The D37 on any survival curve will be equal to or greater than Do.

___ f. Two different populations of mammalian cells (i.e., lung cells and liver cells) were irradiated with 1MeV gamma rays to produce cell survival curves. The Do for the

lung cells was measured to be 100 rads and the Do for liver cells was 500 rads. From this data, you would conclude the liver cells to be more sensitive than the lung cells.

___ g. The hydrated electron (e¯ ) is considered to be a free radical produced during irradiation of cells by X-rays.

___ h. On the average, a fast neutron will lose a larger fraction of its kinetic energy when it collides with the nucleus of a Calcium atom compared to when it

collides with the nucleus of a Hydrogen atom.

Exam 3 – Introduction to Radiation Biology

November 10, 2011 Dr. Lattimer

For each of the following questions please choose the one best response to the question.

1. Which of the following is the most biologically important target for ionizing radiations interaction with biological systems.

a. The DNA

b. The cell wall

c. The mitochondria

d. The nuclear membrane

e. The RNA

2. Which of the following is the approximate amount of injury to the target in the previous question that occurs as a result of direct interaction of photons with the target.

a. 20%

b. 30%

c. 50%

d. 70%

e. 80%

3. For injuries to the DNA which of the following is the most serious?

a. Base pair deletion

b. Cross linkage break

c. Single strand break

d. Double strand break

e. Ribose deletion

4. Large portions of DNA can be lost from a chromosome during which of the following parts of the cell cycle?

a. G0

b. G1

c. S

e. G2

d. M

5. Which of the following radiation induced chromosomal aberrations would likely result in the greatest loss of DNA when the cell goes through its reproductive cycle.

a. Chromotid exchange

b. Sister union

c. Acentric fragments.

d. Chromosomal rings

e. centromere duplication

6. Replication of the DNA is an important first step in a cell’s preparation for division. In which phase of the cell cycle does this occur?

a. G0

b. G1

c. S

d. G2

e. M

7. Repair of radiation injury is part of a cell’s normal metabolic processes. It has been observed that this repair capability is greatest during S phase of the cell cycle. Which of the following may represent a reason that this is so?

a. Intracellular repair mechanisms are already working during S-phase

b. There is more DNA present to serve as a template the repair mechanisms

c. The cell is more metabolically active at many levels during S-phase

d. There are repair pathways available not present in other phases of the cell cycle

e. All of the above.

8. Which of the following represent intracellular radiation damage that is not repaired under normal circumstances but may represent a reason that hypoxic cells are more resistant to radiation injury.

a. Potentially lethal damage

b. Sublethal damage

c. Leathal damage

d. Mitochondrial DNA damage

e. Messanger RNA damage

9. At the tissue level, there are some apparent differences in the way that tissues respond to radiation injury. Some tissue types display some apparently greater sensitivities that others. Which of the following tissue type displays the most apparent sensitivity to ionizing radiation?

a. Skin

b. Small intestinal mucosa

c. The testicles

d. Bone marrow

e. Pulmonary epithelium

10. Which of the following types of cells as described by Rubin and Casarett would likely display the least functional derangement as a result of a single dose of 10 Gray?

a. Vegetative intermitotic cells

b. Differentiating intermitotic cells

c. Multipotential Connective tissue cells

d. Reverting Post Mitotic cells

e. Fixed Post Mitotic cells.

11. Which of the following classification of cells is most likely to have the most potential for mutation following a single 3 Gray dose of ionizing radiation.

a. Vegetative intermitotic cells

b. Differentiating intermitotic cells

c. Multipotential Connective tissue cells

d. Reverting Post Mitotic cells

e. Fixed Post Mitotic cells.

12. The Michaelowski Classification of cell types refers to hierarchical type cells as one of the major types of cells in the classification scheme. Actively dividing cells in this group would be representative of which of the cell types in the Rubin and Casarett classification?

a. Vegetative intermitotic cells

b. Differentiating intermitotic cells

c. Multipotential Connective tissue cells

d. Reverting Post Mitotic cells

e. Fixed Post Mitotic cells.

13. Critical cells in a tissue are which of the following?

a. Dividing cells required for the survival of the tissue

b. The most metabolically active cells in the tissue.

c. Cells in the tissue with the shortest cell cycle time

d. The cells that perform the “work” of that tissue

e. The cells in the tissue that line the blood vessels

14. Intracellular repair of radiation injury is a time sensitive process. How long after a radiation event do most cells to complete repair of the repairable injury from that event?

a. 1 hour

b. 2 hours

c. 4 hours

d. 6 hours

e. 8 hours

15. Which of the following would likely have the greatest effect on a normal cell’s ability to repair radiation injury?

a. Hyperthermia

b. Hypoxia

c. Hypothermia

d. Hyperoxia

e. Short cell cycle time

16. Which of the following approximate doses of radiation would be expected for most people to receive in a year from normal background radiation such as solar, cosmic and geologic sources?

a. 1 cGy

b. 3 cGy

c. 5 cGy

` d. 7 cGy

e. 9 cGy

17. Assays of various types have been used to develop many of the survival curves used in radiation biology. Which of the following assays measures a cell’s ability to reproduce itself?

a. Lethality assay

b. Transplantation assay

c. Clonogenic Assay

d. Functional assay

e. In situ assays

18. Many tissues have substantially more cells to perform a function than is required which allows them to provide adequate support of the animal even after a radiation event. Which of the following assays is a largely measure of this capability?

a. Lethality assay

b. Transplantation assay

c. Clonogenic Assay

d. Functional assay

e. In vivo assays

19. The cell survival curve shoulder is very important in radiation biology, particularly when considering the effects of photon irradiation. It is a manifestation of which of the following?

a. Reassortment

b. Reoxygenation

c. Repopulation

d. Repair

e. Recruitment

20. Which of the following is important in the healing of early responding tissues following a radiation event that is in the range of D0?

a. Reassortment

b. Reoxygenation

c. Repopulation

d. Repair

e. Recruitment

21. Which of the following represents a chronic change in an early responding tissue?

a. Scar tissue formation

b. Hyperemia\

c. Desquamation

d. Ulceration

e. Necrosis

22. Which of the following would represent an acute change in a later responding tissue?

a. Hyperemia

b. Scar tissue formation

c. Depigmentation

d. Cellular replacement

e. Atrophy

23. Acutely responding tissues are generally tissues with large number of cells that have short cell cycle times. Which of the following tissues would be representative of an acute responding tissue?

a. Liver

b. Bone

c. Heart

d. Fat

e. Oral mucosa

24. Acutely responding tissues may also be tissues which have critical cells in them which are slowly dividing but are very radiosensitive and prone to intermitotic death. Which of the following represents such a tissue?

a. Muscle

b. Brain

c. Lung

d. Ovaries

e. Skin

25. All tissues have critical cells in them which determine the maximum dose which that tissue can recover from. Which of the following is sometimes referred to as the default critical cell for any tissue?

a. Plasma cells

b. Endothelium

c. Macrophages

d. Fibroblasts

e. Epithelium

26. Late responding tissues also exhibit chronic changes. Which of the following would be the expected chronic change in fat below the skin following a course of radiation therapy?

a. Hyperemia

b. Scar tissue formation

c. Depigmentation

d. Cellular replacement

e. Atrophy

27. With regards to whole body radiation exposure it is more appropriate to think of critical tissues than critical cells. Which of the following tissues essentially determines the maximum whole body dose an individual can receive and survive?

a. Intestinal epithelium

b. Lung epithelium

c. Bone marrow

d. Liver parenchyma

e. Brain

28. In whole body radiation events there is usually one general cause of death except in cases of extremely high doses. Which of the following is that cause?

a. Infection

b. Anemia

c. Dehydration

d. Pulmonary failure

e. Starvation

29. Which of the following represents a whole body radiation dose which would usually be survivable without medical support?

a. 2.5 Gy

b. 5.0 Gy

c. 7.5 Gy

d. 10 Gy

e. 12.5 Gy

30. There is a period of time following a whole body radiation event when the patient does not feel and clinical effects from the irradiation event even if it is at a level where a significant clinical effect is to be expected. This period of time is referred to as what?

a. Prodromal Stage

b. Latent Stage

c. Manifest Illness Stage

d. Clinical stage

e. Initial stage

31. Which of the following syndromes results in death following a whole body radiation event but very few if any microscopic changes in the victims tissues.

a. Bone Marrow Syndrome

b. Pulmonary Syndrome

c. GI Syndrome

d. Central Nervous System Syndrome

e. All of the above

Name__________________________

Introductory Radiation BiologyFinal Exam, 2011

1. A radiation worker received a whole body dose of 4,000 mrem from a fast neutron source.

a. Assuming the Quality Factor (QF) is 10 relates to a “whole body” dose of the fast neutron radiation, calculate the dose this worker received in mrad units

(Show work).

b. The 4,000 mrem dose in mSv units is ______________ mSv.

2. The “Roentgen” unit is considered to be a measure of the:

a. Absorbed Radiation Doseb. Equivalent Radiation Dosec. Exposure Radiation Dosed. Relative Radiation Dose

3. a) Current estimates are that approximately _____ % of the U.S. population will contract (get) cancer sometime in their lifetime. It is also estimated that approximately ______ of the U.S. population is expected to die from cancer.

b) A population in a U.S. city of 100,000 people received an average radiation dose from gamma-rays of approximately 10 rem (per person). According to the risk estimates presented in class and your textbook (i.e., Hall and Giaccia), approximately _________ people in this city will be expected to die from cancer induced by this radiation exposure (Show work in your calculation).

4. Briefly explain why there will be less repair of radiation damage to mammalian cells induced by a 100 rad (1 Gy) irradiation with a MeV alpha particle beam compared to when these same cells were irradiated with a 100 rad (1 Gy) dose from a 1 MeV beam of gamma rays ( a diagram or sketch should help).

5. All of humanity lives in an environments and societies where they receive some levels of exposure from natural and man-made sources of ionizing radiation.

a. Two (of the three) sources of “Natural” background radiation (not including radon) are ___________________ and

________________________________.

b. The average annual radiation dose to a person in the U.S. population from radon is estimated to be _________ mRem (or mSv)

c. The average annual radiation dose to a person in the U.S. population from all medical diagnostic procedures (including CT, other X-rays, and Nuclear

Medicine is estimated to be __________________ mRem (or mSv).

6. Explain the reasons epidemiologists are able to demonstrate measurable increases (i.e., significantly higher than background levels of spontaneous cancers) of radiation induced leukemia and thyroid cancers in human populations at lower dose levels (e.g., 10-30 Rem whole body exposures) compared to the higher doses required to demonstrate statistically significant increases in radiation induced colon and lung cancers. Hint, there can be two general contributing factors.

7. Human kidney cells were irradiated with a beam of 4 MeV alpha particles at a high dose rate in the presence of oxygen to produce a cell survival curve.

a. You would expect that the extrapolation number (n) on the cell survival curve will be approximately:

i. oneii. less than oneiii. much greater than one

b. The degree of “Elkind Repair” that would be expected to occur in the cells remaining alive after a dose of 300 rads would be:

i. minimalii. Quite highiii. Greater than when compared to cells that had been irradiated at 300 rads with a

beam of 1 MeV gamma rays.

8. Briefly define or describe

a. D37 (obtained from survival curve)

b. Free radical

c. Indirect effect

d. Sub-lethal damage to the DNA in cells by ionizing radiation.

e. Excision repair of damaged DNA bases.

f. Name two types of effects that may be produced (to a statistically significant increase) caused by in utero exposure of a fetus in the first trimester at a dose of 100 rads.

9. True-False

___ a. There are a few types of congenital malformations that result from in utero irradiation of the embryo or fetus in the first trimester that are not found

“spontaneously” in new born infants.

____ b. Analysis of A-bomb survivor data has been able to demonstrate a significant increase in radiation-induced cancers in this population, but has not been

able to demonstrate a statistical increase in radiation-induced genetic (hereditary) effects.

___ c. You would expect that following irradiation of a population of humans, where the average whole body radiation dose was approximately 2 Rem, a long-

term follow-up study of this population will show a significant increase in cancer incidence that can be directly related to the 2 Rem radiation exposure.

___ d. It has been shown that the rate of induction of thyroid cancers in human populations as a function of radiation dose to the thyroid gland is

approximately the same in adults as it is in young children.

___ e. Results from studies on the A-bomb survivor population in Japan estimate that the number of cancers induced by the A-bomb associated exposures was

totaled to be approximately 5% of the number of cancers occurring spontaneously in this population.

___ f. Molecular oxygen will be able to provide mammalian some level of protection from low LET ionization radiation.

___ g. You would not expect to be able to statistically demonstrate an increase of congenital malformations after irradiation of a fetus in the first trimester

with a dose of 4,000 mrads from X-rays.

INTRODUCTORY RADIATION BIOLOGY 7328/4328

FINAL EXAM QUESTIONS 2011—Michael R. Lewis, Ph.D.

1. Rank the following ionizing radiations in order of increasing LET (i.e., beginning with the lowest LET; e.g., a < b < c < d < e, but please note that this may or may not be the correct answer!).

500 keV proton

a. 5 MeV alpha particleb. 1 MeV beta minus particlec. 140 keV gamma rayd. 500 keV alpha particlee. 500 keV positron

2. Lutetium-177 (17771Lu; T1/2 = 6.65 days) decays to 177

72Hf (stable). In 89% of events, 177Lu decays to the ground state of 177Hf, while in 11% of events, it decays to an excited state of 177Hf that lies 208 keV above the ground state, which de-excites in <1 ns to the ground state.

a. Sketch a decay scheme that is consistent with this information.

b. True or False (circle one): 177Lu decay can be imaged using a gamma camera.c. True or False (circle one): 177Lu cannot be used for radionuclide therapy.d. Dr. Mike Lewis has obtained very promising data evaluating 177Lu radiopharmaceuticals for

cancer. During one of his experiments (based on a true story), a coworker spilled 177Lu on the floor, Dr. Lewis stepped in it, and he could not clean it off his shoe. How long (in days) did it take for the 177Lu to decay to 0.1% of its original level, so it was safe for Dr. Lewis to wear those shoes again?

3. Briefly define or describe (no more than 1-2 sentences):

a. The type of radiation that positron emission tomography (PET) scanners detect

b. Half-life of a radionuclide

c. Marie Curie

d. The radionuclide or radiopharmaceutical used to treat thyroid diseases, like hyperthyroidism and well differentiated thyroid carcinoma

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. Mean free path

g. Wilhelm Conrad Röntgen

h. Ionizing radiation

TRUE/FALSE

4. _____A 1 MeV alpha particle will have higher LET over its track and greater relative biological effectiveness (RBE) than a 1 MeV beta minus particle.

5. _____18F decays by positron emission, which makes it highly useful for diagnostic imaging, especially of cancer.

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

7. _____Radionuclides produced by nuclear reactors generally decay by beta minus emission, making them potentially useful for targeted radiotherapy.

MULTIPLE CHOICE

8. If a patient shows high uptake of 99mTc-MDP in bone tumors, he or she is potentially a good candidate for therapy with

a. Na131I (sodium iodide).b. 153Sm-EDTMP (QuadraMet™).c. 201TlCl (thallium chloride).d. all of the above.e. none of the above.

9. [18F]Fluorodeoxyglucose (18F-FDG) accumulates predominantly in brain and tumors because

a. these tissues derive much of their energy from glucose.b. the radiopharmaceutical gets “metabolically trapped” inside their cells.c. these tissues have high rates of glucose metabolism.d. all of the abovee. none of the above

10. The component of a gamma camera that defines (or “focuses”) the field of view and ensures that a small part of the detector “sees” only a small part of the organ or tissue being imaged is the

a. sodium iodide crystal.b. photomultiplier tube array.c. collimator.d. pulse height analyzer.e. patient bed.

11. Which one of the following agents is not used for physiologic imaging?

a. 18F-FDG.b. diagnostic x-rays.c. 99mTc-MDP.

d. 201TlCl.e. 99mTc-Sestamibi.

Final exam questions: Dr. Lattimer

1. Which of the following represents the principal means by which DNA is injured by ionizing radiation?

a. Direct interaction of the radiation with the base pairs of the DNA

b. Direct interaction of the radiation with the side strands of the DNA

c. Indirect action of recoil oxygen on the DNA side strands after ionization of water

d. Indirect action on the Sulfhydrl cross-linking of the DNA by reactive oxygen species

e. Indirect action on the DNA strands and base pairs by reactive OH- species.

2. Injury to which of the following cell types is likely to result in the least demonstrable cell death?

a. Vegetative intermitotic cells

b. Differentiating intermitotic cells

c. Mulipotential connective tissue cells

d. Reverting Post Mitotic cells.

e. Fixed Post Mitotic cells.

3. Which of the following organs is most susceptible to radiation injury?

a. Lung

b. Liver

c. Heart

d. Spinal Cord

e. Bone

4. The phase of organogenesis is the period of fetal development during which irradiation has the highest potential to cause birth defects. Organogenesis ends at the end of which of the follow weeks post conception in humans?

a. 4th week

b. 6th week

c. 8th week

d. 8th week

e. 10th week

5. Which of the following is a radiation dose which is generally considered to represent a dose below which no detectable radiation injury will occur?

a. 1 cGY

b. 5 cGy

c. 10 cGY

d. 25 cGy

e. 50 cGy

6. Which of the following types of assays would be most likely used to study the effect of a dose of radiation the metastatic potential of a given tumor type in mice.

a. in vitro Clonogenic assay

b. in vivo Clonogenic assay

c. in vitro Transplantation assay

d. in vivo transplantation assay

e. in vivo lethality assay

7. With respects to the reaction of tissues and tumors to a dose of radiation, which of the following is thought to only occur in tumors?

a. Repair

b. Reoxygenation

c. Regeneration

d. Reassortment

e. Recruitment

8. Which of the following types of radiation is most likely to result in a large amount of non-repairable radiation injury for the same delivered dose?

a. X-rays

b. Gamma rays

c. Electrons

d. Protons

e. Alpha particles

9. Which of the following represents an effect of fractionation of the radiation dose in administration of radiation for treatment of cancer?

a. Improves disease control to complication rate

b. Decreases late effects in acutely responding tissues

c. Decreases late effects in late responding tissues

d. Improves tumor oxygenation

e. All of the above.

10. Radiation treatment with protons has been gaining favor a means of treating cancer. Which of the following is a major roadblock for a hospital wishing to start using this type of treatment?

a. Shielding requirements for the protons

b. Limited number of cancers which can be treated

c. Cost of the equipment and installation

d. Difficulty in properly administering dose of radiation prescribed

e. Increase number of late radiation effects.