Test
PMU - Year 1 Physics - Part 4(A)
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Preguntas del test (69)
1Protons and neutrons in a nucleus are termed:
- ABeta-particles
- BPhotons
- CNucleons
2Linear attenuation coefficient of photoelectric absorption (photoelectric effect interaction probability) τ is:
- AInversely proportional to the atomic number of the element Ζ
- BInversely proportional to the mass number A
- CProportional on the density ρ
3Linear attenuation coefficient of photoelectric absorption τ depends strongly (approximately to the 4-th power) on:
- AThe density of substance
- BThe atomic number of element Z
- CThe temperature of substance - t
4Linear attenuation coefficient for Compton effect (Compton scattering interaction probability) δ is proportional to:
- AAtomic mass number A
- BDensity of substance
- CThe ratio A/Z
5Linear attenuation coefficient for Compton effect is proportional to:
- ApZ4
- BpZ2
- CpZ/A
6Linear attenuation coefficient for pair production (electron-positron production probability) X is proportional to:
- AAtomic mass number A
- BThe square of the atomic number of the element Z2
- CThe ratio of A/Z
7Predominant mode of interaction between conventional diagnostic x-ray and biological tissues (Figure 11. not included) is:
- APair production (electron-positron)
- BPhotoelectric absorption
- CCompton effect (scattering)
8Interaction of photonic ionizing radiation with matter will
- AReduce radiation intensity
- BNot change radiation intensity
- CIncrease radiation intensity
9What type of interaction between diagnostic x-rays and matter is improbable:
- APhotoelectric absorption
- BPair production (electron-positron)
- CCompton effect
10Consider attenuation of photon beam in water/soft tissue (figure 11. not included). Which statement is true:
- APhotons may undergo two successive photoelectric transitions
- BCompton scattering has a threshold energy of 1.022 MeV
- CPhotoelectric effect increases with photo energies
- DPhotoelectric and Compton effects equal at 25 KeV
11Roentgen Rays are:
- APhotons
- BElectrons
- CPositrons
12Roentgen rays are:
- AElectromagnetic Radiation:
- BProtons
- CElectrons
13X-rays have
- AA wavelength longer than that of the visible light
- BPositive Electric Charge
- CIonizing Capacity
14The wavelength of the roentgen radiation is within the range of:
- A380 - 760 nm
- B0.76 - 1000 µm
- C10 - 380 µm
- DLess than 10 nm
15X-rays have:
- AFrequency higher than that of the visible light
- BDirect ionizing capacity
- CNegative electric charge
16Characteristic x-ray radiation:
- AHas continuous energy spectrum
- BDoes not differ from braking radiation spectrum
- CIs obtained from K and L shell electron transitions from high atomic shells.
17Continuous x-ray energy spectrum:
- AContains several photons with different energy
- BDoes not differ from the characteristic x-ray spectrum
- CIs a result of rapid deceleration of electrons near target nuclei
18Intensity ψ of radiation in x-ray tube is proportional to:
- AThe atomic number Z of anode's material
- BThe 3-th power of anode U3/a
- CThe 2-nd power of anode I2/a
19Intensity ψ of roentgen radiation (x-ray tube) is proportional to:
- AThe 3-th power of anode voltage U3/a
- BThe anode current Ia
- CThe 2-nd power of the atomic number Z2 of anodes material.
20Intensity ψ of roentgen radiation (x-ray tube) if proportional to:
- ADensity p of the cathode material
- BThe 2-nd power of anode voltage U2/a
- CThe 2-nd power of anode current I2/a
21Minimum wavelength λmin (maximum energy) of x-ray tube radiation depends on:
- AAnode Voltage Ua
- BAnode current
- CThe atomic number Z of the element of which anode is made
- DDensity p of the material of which cathode is made
22Filters in x-ray apparatus modify:
- AThe minimum wavelength λmin of x-ray braking spectrum
- BThe amount of anode Voltage Ua
- CThe intensity ψ of roentgen radiation
23Intensity ψ of the Roentgen rays is proportional to:
- AU2IZ
- BUI2Z
- CUIZ2
24Hardness of x-ray radiation (harder/softer) is changed by:
- AAnode voltage Ua
- BBeam intensity ψ
- CAnode current Ia
25The relationship between HVL (Half Value Layer) and linear attenuation coefficient µ is
- AHVL = ln(2)/µ
- BHVL = µ/ln(2)
- CHVL = µ*ln(2)
26Water is said to be soft tissue equivalent with respect to x-ray attenuation. This is because water and soft tissue have approximately the same properties. Which properties are NOT the same? (there are more than one correct answers)
- AEffective atomic number Zeff
- BEffective molecular weight
- CPhysical density p
- DAttenuation Coefficient µ
27The purpose of the introduction of contrast substances in the roentgen diagnostics is to:
- AObtain coloring in the roentgenogram and not only black and white images
- BIncreasing the contrast between soft tissues
- CReduce the radiation dose on patients
28Contrast substances in diagnostics radiology will:
- AIncrease contrast between different soft tissues
- BIncrease contrast between soft tissues and bones
- CObliterate cancer cells
29Which of the listed chemical elements provides maximum contrast in diagnostic radiology:
- ACalcium: Z = 20, p = 1.55 g/cm3
- BBarium: Z = 56, p = 3.5 g/cm3
- CIodine: Z = 53, p = 4.94 g/cm3
30Roentgen osteo-densitometry (measurement of bone density) is based on which of the following phenomena:
- ADiffraction of roentgen rays (x-rays)
- BScattering of roentgen rays (x-rays)
- CAttenuation of Roentgen rays (x-rays)
31Hounsfield Unit (CT number) for bones is equal to:
- A0
- Bup to (+3000)
- C(-1000)
32Hounsfield unit (CT number) for air is equal to:
- A0
- BUp to (+3000)
- C(-1000)
33Hounsfield unit (CT number) for water is equal to:
- A0
- Bup to (+3000)
- C(-1000)
34Hounsfield unit (CT number) is defined as:
- A(µ-tissue + µ-water) / µ-water
- B(µ-tissue - µ-water) / µ-water
- C(µ-tissue - µ-water) / µ-tissue
35Predominant x-ray interaction mode in CT scanning is:
- APhotoelectric absorption & compton scattering
- BElectron-positron pair production & photoelectric absorption
- CCompton scattering & electron-positron pair production
36CT diagnostic imaging is based on the phenomenon of:
- AReflection of reoentgean rays at the boundary between different structures
- BAbsorption of roentgen rays by tissues exposed to radiation
- CAttenuation of roentgen rays by tissues exposed to radiation
37What is the meaning of "computed" in name of CT (computed tomography)?
- ACalculation of radiation dose
- BControl of the scanning process
- CFormation of the final image
38Computed tomography uses higher anode voltage compared to conventional roentgenography because
- APatients are placed further away from x-ray source
- BRotation of x-ray tube exposes more massive parts of patients body radiation
- CCT x-ray detectors are less sensitive
39CT exposes pateints to higher radiation doses compared to conventional roentgenography (x-ray imaging) because:
- AAnode voltage is higher
- BMultiple images are taken
- CBoth A and B
40Radionuclides used in "in vivo" radionuclide diagnostics are:
- AAlpha-radionuclides
- BBeta-radionuclides
- CGamma-Radionuclides
41What type of radioactivity is related to SPECT radionuclide diagnostics:
- ABeta
- BAlpha
- CGamma
42Alpha-rays are a beam of:
- AElectrons
- BHelium nuclei
- CPositrons
43Radiopharmaceuticals are:
- AContrast substances used in MRI
- BContact gels used in ultrasound diagnostics
- CChemical compounds containing radioactive isotopes
44The following quantity participates in the law of radioactive decay:
- AHuddersfield unit (CT-number)
- BIndex of refreaction n
- CLinear attenuation coefficient
- DDecay constant
45Half-life T1/2 is defined as:
- AEnergy of gamma-radiation
- BProbability of radioactive decay
- CThe time it takes for radioactivity to be reduced by half.
46Isomeric transition is a type of decay that changes:
- AThe atomic number Z of the element
- BThe energy of the nucleus
- CThe mass number A of the nucleus
47Radionuclides produced in generators have:
- ALong half-life T1/2
- BShort half-life T1/2
- CHigh energy gamma-radiation
48Radionuclide generators contain:
- AOnly gamma-radionuclides
- BA meta-stable mother radionuclide
- CA metastable daughter radionuclide
- DMother (parents) and daughter radionuclides - metastable radionuclides
49Radionuclides are:
- ATransformers of radiowaves
- BRadioactive nuclei
- CUltrasound detectors
50How does activity of a radio-pharmaceutical change after sterilization for intravenous application (sterilization time ignored):
- AReduces abruptly due to chemical changes
- BIncreases abruptly due to chemical changes
- CRemains unchanged
51Radio-pharmaceuticals used in nuclear medicine include:
- AElements with radioactive nuclei
- BTransformers of infared rays
- CSources of ultrasound
52Radio-pharmaceuticals used for "in vivo" diagnostics contain radionuclides with the following mode of radioactivity:
- AIsometric Transition
- BBeta minus decay
- CAlpha decay
53Time required for intial activity A0 for a radioactive source to decay to 10% is between:
- A1 and 2 half-lives
- B2 and 3 half-lives
- C3 and 4 half-lives
- D4 and 5 half-lives
54The decay constant for 182TA is 0.006 day-1. Which is its half life:
- A0.006 days
- B83 days
- C115 days
- D167 days
55The phenomenon of radioactivity is associated with:
- ADecay of atoms
- BDecay of nucleus
- CFusion of nuclei
- DEmission of valence Orbital electrons
56Electron capture involves:
- AAn electron combining with a neutron
- BA neutron being ejected from the nucleus
- CAn electron combining with a proton
- DAn electron being ejected from the nucleus
57In alpha decay:
- AZ and A are unchanged
- BZ decreases by 4 and A decreases by 2
- CZ decreases by 2 and A decreases by 4
- DZ decreases by 4 and A decreases
58Isomeric transition involves:
- AThe emission of a gamma-ray
- BThe conversion of a neutron to a proton
- CThe conversion of a proton to a neutron
- DElectron Capture
59An alpha-particle consists of:
- AOne proton and two neutron
- BTwo proton and one neutron
- CTwo proton and two neutron
- DOne proton and One neutron
60For pair production interactions it is true that:
- AHave no energy threshold
- BOccur near the electric field of the nucleus
- CProduce 1.022 MeV annihilation radiation
- DAre important in diagnostic radiology
- EAll of the above
6199Tc-m has a half-life t1/2 = 6h. What is the approximate value of 99tc-m decay constant:
- A0.12 sec-1
- B0.12 min-1
- C0.12 hr-1
62After 40 half-lives have elapsed, the activity A of radionuclide is equal to:
- AA0/40
- BA0/(2*40)
- CA0/(2 40)
63Polonium-210 has a half-life of 4.5 months, and decays into the stable daughter isotope of lead-206. By measuring the proportion of polonium to lead in a sample, one can establiosh the production date of polonium. If the proportion is 1:15 (Po:Pb), how many months have elapsed since production date?
- A3
- B15
- C18
64What type of radiation can NOT be detected with scintillation detector?
- AAlpha particles
- BBeta Particles
- CGamma Rays
65Ionizing radiation used for "In vivo" radionuclide diagnostics:
- AAlpha and gamma radiation
- BBeta minus radiation
- CGamma and annihilation radiation
66Which quantity is NOT a parameter of radionuclides:
- AActivity A
- BHalf-Life T1/2
- CRadiation yield
- DDecay constant
67Activity A is a parameter of:
- ALaser radiation
- BRadionuclides
- CRadioactive sources
68Why is technetium-99m (99mTC) preferred over iodine-131 (131-I) for thyroid gland diagnostics?
- A99mTC is more cost-effective
- B99mTC has fewer side effects
- C99mTC is a "pure" gamma source and the radiation is orders of magnitude less
- DNatural deposits of 99mTC exists in some tissues
691987 an old radiotherapy source of cesium-137 (T1/2 = 30 years) was stolen from an abandoned hospital in the brazilian city of goiania. It was subsequently handled by many people, resulting in four deaths and 249 cases of high radiation exposure. If the activity of the source was 74TBq (Terebecquerels) in 1971, what was the activity in the time of the accident?
- A51 TBq
- B37 TBq
- C30 TBq
Información
- Descripción
- All Questions uploaded word for word from MCQ book. All Credit to Authors. Mistakes due in process may have been made, use and check your work at your own discretion. Only simple writing allowed, i.e Superscript and Subscript absent. Questions missed due to Figure/Diagrams/Text: 11.44.46.57
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