1.The RBE of x-rays is related to LET. What is the energy of X-rays that has the
ID: 201463 • Letter: 1
Question
1.The RBE of x-rays is related to LET. What is the energy of X-rays that has the maximum RBE?
10 KeV/u
100 KeV/u
100 MeV/u
1 MeV/u
2. How many tracks of radiation would you expect to traverse the nucleus of every cell in a tumour if you treated the tumor with one fraction of 2mGy?
a) 2 tracks
b) 200 tracks
c) 2,000 tracks
d) 20,000 tracks
3. What is the size of a human X-chromosome compared to a red blood cell?
a) bigger
b) same size
c) smaller
d) longer but not wider
4. You have just delivered a single 2.0 Gy dose broad beam field to a tumor. How many DNA double strand breaks (DSB) might you expect to be produced in each tumor cell?
a) 4 DSBs
b) 40 DSBs
c) 80 DSBs
d) 20 DSBs
5. What important radiation cancer risk gene is inactivated when women are infected with HPV and get increased risk of cancer of the cervix (sexually transmitted cancer)?
a) Rad 51
b) AT
c) p53
d) XP
6. Indirect DNA damage is more prevalent with:
a) High RBE
b) High LET
c) Gamma rays
d) Alpha Particles
7. Name two types of radiation-induced cancer risk genes.
a)
b)
8. if 500 cells were put into a petri dish to study survival curves and the plating efficiency was 20%, how many colonies might you expect to form in the un-irradiated control dish?
a) 500
b) 200
c) 20
d) 100
9. If 500 cells were put into a petri dish to study survival curves and the plating efficiency was 90%, how many colonies might you expect to form in a dish that got a dose of 4 Gy?
a) 450
b) 225
c) 25
d) 9
10. What is one of the possible pathways a cell may undergo after being irradiated with UV radiation?
a) Error Prone Repair with Non-Homologous End Rejoining (NHEJ)
b) Error Prone Repair with Homologous Recombination (HR)
c) Error Free Base Excision Repair of DNA Cross Links
11. What would “children of the moon” be susceptible to?
a) UV light
b) Moon light
c) moon shine
d) x-rays
12. Inside ten single cells there is about how much DNA?
a) 1 km
b) 10m
c) 365 trips from the sun to earth
d) 1 m
13. Would you expect a person’s head hair to fall out when given a normal CT scan to the head?
a) true
b) false
14. The oxygen effect is less with what type of radiation?
a) high LET radiation
b) low LET radiation
c) Gamma particles
d) Gamma rays
15. What type of DNA repair would predominate after high LET radiation exposure?
a) base excision repair
b) homologous recombination
c) single strand break repair
d) dimer repair
16. What type of DNA repair is error free?
a) homologous recombination
b) non-homologous end rejoining
c) excision mismatch repair
d) Branch migration
17. When cells from an AT patient are irradiated with a high dose what can happen?
a) inhibit cell cycle arrest
b) slower DNA replication
c) increased sensing of DNA damage
d) illegitimate recombination
18. What is the LD 50 (30) for humans?
a) 4 Gy
b) 0.5 Gy
c) 20 Gy
d) 100 mGy
19.What phase in the growth curves happens after the plateau phase?
a) lag phase
b) contact phase
c) exponential phase
d) none of the above
20. Based on cell survival curves, the most radio-resistant cells are:
a) bone marrow cells
b) mammary cells
c) testis stem cells
d) Human Ataxia Telangiectasia and bone marrow stem cells
21. Which cells are most radiation sensitive?
a) slow growing cells
b) cells in cell cycle arrest
c) rapidly dividing cells
d) cells from the CNS
22. How many DNA single strand breaks could occur after a 2 Gy dose to a cell?
a) 40
b) 100
c) 2,000
d) 500
23. X-rays have a steeper survival curve than alpha particles.
a) true
b) false
24. The Oxygen Enhancement Ratio (OER) would be greater with what type of radiation?
a) Gamma rays
b) Neutrons
c) Neutrinos
d) Alpha Particles
25. How many genes does a human have?
a) 100,000
b) 25,000
c) 50,000
d) 2,500
26. What percentage of men over the age of 85 have some degree of prostate cancer?
a) 25%
b) 50 %
c) 75%
d) 100%
27. What did Wilhelm Roentgen discover?
a) Radium
b) X-rays
c) Uranium
d) Radiendocrinator
28. What dose would cause the ARS Bone Marrow Syndrome?
a) 15 Gy
b) 5 Gy
c) 0.1 Gy
d) 30 Gy
29. Which of the following radiation effects on fertility can occur in both males and females?
a) temporary sterility
b) permanent sterility
c) hormone changes
d) latent period between irradiation and sterility
30. Acute hypoxia occurs when:
a) Cells are more than 70 um away from the closest blood vessel
b) cells die from a complete lack of oxygen
c) cells have reduced oxygen levels due to temporary closing of blood vessels
d) none of the above.
31. The radiation dose received from a DEXA scan is equivalent to eating ___ bananas.
a) 2
b) 4
c) 10
d) 20
32. Lower dose rates generally result in less radiation damage due to:
a) repair during exposure
b) repair after exposure
c) tissue re-oxygenation
d) cell cycle redistribution
33. Approximately what percentage of the annual human radiation exposures comes from medical procedures?
a) 25%
b) 50 %
c) 75%
d) 100%
34. Which of the following effects have been observed in the children born from mothers exposed to high doses of radiation from the atomic bomb?
a) Prenatal death
b) Exenchaphaly
c) evisceration
d) Cognitive impairment
35. Death from CNS syndrome results from:
a) increased intracranial pressure
b) destruction of neurons
c) damage to the brainstem
d) reduction in white blood cell count
36. The most noticeable change in cell sensitivity to radiation due to oxygen occurs around which concentration?
a) atmospheric (21%)
b) 100%
c) venous blood (20-40 mm Hg)
d) less than 5%
37. The risk of neonatal death in mice is greatest when irradiated at which development stage?
a) conception
b) pre-implantation
c) organogenesis
d) fetal
38. Perfluorocarbons can improve tumour killing during radiation therapy because:
a) perfluorocarbons increase oxygen supply to the tumour and oxygen is toxic to tumour cells
b) perfluorocarbons increase oxygen supply to the tumour and oxygen will sensitize the tumour cells to radiation
c) perfluorocarbons will increase blood flow
d) perfluorocarbons are toxic to tumour cells
39. A radiation dose of 0.5 Gy to males would result in which of the following?
a) temporary sterility
b) complete killing of all mature sperm cells
c) permanent sterility
d) increased hormone production
40. The inverse dose rate is caused by:
a) CNS syndrome
b) Tissue oxygenation
c) Bone morrow syndrome
d) Delays in cell cycle progression
41. Which of the following is not a symptom of the prodromal stage of ARS?
a) Nausea
b) Death
c) vomiting
d) Burning sensation of the skin
42. The majority of cell death following radiation exposure occurs through:
a) mitotic cell death
b) interphase cell death
c) Necrosis
d) none of the above
43. The latent stages of AS comes after what?
a) recovery
b) manifest illness
c) prodromal
d) death
44. In _____ syndrome, the time to death following exposure is not dependent on the radiation dose received.
a) Bone marrow
b) gastrointestinal
c) central nervous system
d) All of the above
45. What dose would be delivered from the average dental X-ray?
a) 10 mGy
b) 100 mGy
c) 1 mGy
d) less than 1 mGy
46. The average mammogram delivers more dose than a full body CT scan.
a) True
b) false
47. How many phenotypic abnormalities would you expect to see in the offspring of a pregnant mouse that was irradiated with 2 Gy and day 16 of gestation?
a) none
b) some short tails
c) many short tails and missing digits
d) no missing digits but many short tails.
48. What single acute dose would cause CNS ARS?
a) 0.5 Gy
b) 30 Gy
c) 10 Gy
d) 60 Gy
49. The therapeutic Ration (index) can be improved by which of the following?
a) CT scan
b) decreasing the dose required to kill 50% of tumor cells
c) increasing the dose required to kill 50% of tumor cells
d) decreasing the dose required to kill 50% of surrounding healthy tissue cells
50. Which of the following natural sources contribute to our annual background radiation exposure?
a) Cosmic radiation
b) radon
c) potassium-40
d) all of the above
Explanation / Answer
3) C smaller. RBC - 8micrometer and X-chromosome- 7micrometer
7) a- BRCA1/2 - Breast or ovarian cancer b- XPA-G - melanoma
21) C rapidly dividing cells11) A UV light/sun light
25) A 100,000 genes
27) B X rays
35) B. Damage of neurons
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.