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Protons and neutrons in a nucleus are termed:
Antworten
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Beta-particles
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Photons
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Nucleons
Frage 2
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Linear attenuation coefficient of photoelectric absorption (photoelectric effect interaction probability) τ is:
Antworten
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Inversely proportional to the atomic number of the element Ζ
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Inversely proportional to the mass number A
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Proportional on the density ρ
Frage 3
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Linear attenuation coefficient of photoelectric absorption τ depends strongly (approximately to the 4-th power) on:
Frage 4
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Linear attenuation coefficient for Compton effect (Compton scattering interaction probability) δ is proportional to:
Antworten
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Atomic mass number A
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Density of substance
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The ratio A/Z
Frage 5
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Linear attenuation coefficient for Compton effect is proportional to:
Frage 6
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Linear attenuation coefficient for pair production (electron-positron production probability) X is proportional to:
Frage 7
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Predominant mode of interaction between conventional diagnostic x-ray and biological tissues (Figure 11. not included) is:
Frage 8
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Interaction of photonic ionizing radiation with matter will
Antworten
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Reduce radiation intensity
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Not change radiation intensity
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Increase radiation intensity
Frage 9
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What type of interaction between diagnostic x-rays and matter is improbable:
Frage 10
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Consider attenuation of photon beam in water/soft tissue (figure 11. not included). Which statement is true:
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Photons may undergo two successive photoelectric transitions
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Compton scattering has a threshold energy of 1.022 MeV
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Photoelectric effect increases with photo energies
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Photoelectric and Compton effects equal at 25 KeV
Frage 11
Antworten
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Photons
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Electrons
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Positrons
Frage 12
Frage 13
Frage 14
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The wavelength of the roentgen radiation is within the range of:
Antworten
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380 - 760 nm
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0.76 - 1000 µm
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10 - 380 µm
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Less than 10 nm
Frage 15
Frage 16
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Characteristic x-ray radiation:
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Has continuous energy spectrum
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Does not differ from braking radiation spectrum
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Is obtained from K and L shell electron transitions from high atomic shells.
Frage 17
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Continuous x-ray energy spectrum:
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Contains several photons with different energy
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Does not differ from the characteristic x-ray spectrum
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Is a result of rapid deceleration of electrons near target nuclei
Frage 18
Frage
Intensity ψ of radiation in x-ray tube is proportional to:
Antworten
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The atomic number Z of anode's material
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The 3-th power of anode U3/a
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The 2-nd power of anode I2/a
Frage 19
Frage
Intensity ψ of roentgen radiation (x-ray tube) is proportional to:
Frage 20
Frage
Intensity ψ of roentgen radiation (x-ray tube) if proportional to:
Antworten
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Density p of the cathode material
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The 2-nd power of anode voltage U2/a
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The 2-nd power of anode current I2/a
Frage 21
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Minimum wavelength λmin (maximum energy) of x-ray tube radiation depends on:
Frage 22
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Filters in x-ray apparatus modify:
Antworten
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The minimum wavelength λmin of x-ray braking spectrum
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The amount of anode Voltage Ua
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The intensity ψ of roentgen radiation
Frage 23
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Intensity ψ of the Roentgen rays is proportional to:
Frage 24
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Hardness of x-ray radiation (harder/softer) is changed by:
Antworten
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Anode voltage Ua
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Beam intensity ψ
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Anode current Ia
Frage 25
Frage
The relationship between HVL (Half Value Layer) and linear attenuation coefficient µ is
Antworten
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HVL = ln(2)/µ
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HVL = µ/ln(2)
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HVL = µ*ln(2)
Frage 26
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Water 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)
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Effective atomic number Zeff
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Effective molecular weight
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Physical density p
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Attenuation Coefficient µ
Frage 27
Frage
The purpose of the introduction of contrast substances in the roentgen diagnostics is to:
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Obtain coloring in the roentgenogram and not only black and white images
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Increasing the contrast between soft tissues
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Reduce the radiation dose on patients
Frage 28
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Contrast substances in diagnostics radiology will:
Frage 29
Frage
Which of the listed chemical elements provides maximum contrast in diagnostic radiology:
Antworten
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Calcium: Z = 20, p = 1.55 g/cm3
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Barium: Z = 56, p = 3.5 g/cm3
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Iodine: Z = 53, p = 4.94 g/cm3
Frage 30
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Roentgen osteo-densitometry (measurement of bone density) is based on which of the following phenomena:
Antworten
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Diffraction of roentgen rays (x-rays)
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Scattering of roentgen rays (x-rays)
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Attenuation of Roentgen rays (x-rays)
Frage 31
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Hounsfield Unit (CT number) for bones is equal to:
Frage 32
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Hounsfield unit (CT number) for air is equal to:
Frage 33
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Hounsfield unit (CT number) for water is equal to:
Frage 34
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Hounsfield unit (CT number) is defined as:
Antworten
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(µ-tissue + µ-water) / µ-water
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(µ-tissue - µ-water) / µ-water
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(µ-tissue - µ-water) / µ-tissue
Frage 35
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Predominant x-ray interaction mode in CT scanning is:
Antworten
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Photoelectric absorption & compton scattering
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Electron-positron pair production & photoelectric absorption
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Compton scattering & electron-positron pair production
Frage 36
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CT diagnostic imaging is based on the phenomenon of:
Antworten
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Reflection of reoentgean rays at the boundary between different structures
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Absorption of roentgen rays by tissues exposed to radiation
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Attenuation of roentgen rays by tissues exposed to radiation
Frage 37
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What is the meaning of "computed" in name of CT (computed tomography)?
Antworten
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Calculation of radiation dose
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Control of the scanning process
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Formation of the final image
Frage 38
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Computed tomography uses higher anode voltage compared to conventional roentgenography because
Antworten
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Patients are placed further away from x-ray source
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Rotation of x-ray tube exposes more massive parts of patients body radiation
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CT x-ray detectors are less sensitive
Frage 39
Frage
CT exposes pateints to higher radiation doses compared to conventional roentgenography (x-ray imaging) because:
Frage 40
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Radionuclides used in "in vivo" radionuclide diagnostics are:
Antworten
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Alpha-radionuclides
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Beta-radionuclides
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Gamma-Radionuclides
Frage 41
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What type of radioactivity is related to SPECT radionuclide diagnostics:
Frage 42
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Alpha-rays are a beam of:
Antworten
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Electrons
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Helium nuclei
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Positrons
Frage 43
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Radiopharmaceuticals are:
Antworten
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Contrast substances used in MRI
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Contact gels used in ultrasound diagnostics
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Chemical compounds containing radioactive isotopes
Frage 44
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The following quantity participates in the law of radioactive decay:
Frage 45
Frage
Half-life T1/2 is defined as:
Antworten
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Energy of gamma-radiation
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Probability of radioactive decay
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The time it takes for radioactivity to be reduced by half.
Frage 46
Frage
Isomeric transition is a type of decay that changes:
Antworten
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The atomic number Z of the element
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The energy of the nucleus
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The mass number A of the nucleus
Frage 47
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Radionuclides produced in generators have:
Frage 48
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Radionuclide generators contain:
Antworten
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Only gamma-radionuclides
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A meta-stable mother radionuclide
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A metastable daughter radionuclide
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Mother (parents) and daughter radionuclides - metastable radionuclides
Frage 49
Frage 50
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How does activity of a radio-pharmaceutical change after sterilization for intravenous application (sterilization time ignored):
Frage 51
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Radio-pharmaceuticals used in nuclear medicine include:
Frage 52
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Radio-pharmaceuticals used for "in vivo" diagnostics contain radionuclides with the following mode of radioactivity:
Antworten
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Isometric Transition
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Beta minus decay
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Alpha decay
Frage 53
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Time required for intial activity A0 for a radioactive source to decay to 10% is between:
Antworten
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1 and 2 half-lives
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2 and 3 half-lives
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3 and 4 half-lives
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4 and 5 half-lives
Frage 54
Frage
The decay constant for 182TA is 0.006 day-1. Which is its half life:
Antworten
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0.006 days
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83 days
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115 days
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167 days
Frage 55
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The phenomenon of radioactivity is associated with:
Frage 56
Frage
Electron capture involves:
Antworten
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An electron combining with a neutron
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A neutron being ejected from the nucleus
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An electron combining with a proton
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An electron being ejected from the nucleus
Frage 57
Antworten
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Z and A are unchanged
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Z decreases by 4 and A decreases by 2
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Z decreases by 2 and A decreases by 4
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Z decreases by 4 and A decreases
Frage 58
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Isomeric transition involves:
Antworten
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The emission of a gamma-ray
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The conversion of a neutron to a proton
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The conversion of a proton to a neutron
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Electron Capture
Frage 59
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An alpha-particle consists of:
Antworten
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One proton and two neutron
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Two proton and one neutron
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Two proton and two neutron
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One proton and One neutron
Frage 60
Frage
For pair production interactions it is true that:
Antworten
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Have no energy threshold
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Occur near the electric field of the nucleus
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Produce 1.022 MeV annihilation radiation
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Are important in diagnostic radiology
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All of the above
Frage 61
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99Tc-m has a half-life t1/2 = 6h. What is the approximate value of 99tc-m decay constant:
Antworten
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0.12 sec-1
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0.12 min-1
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0.12 hr-1
Frage 62
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After 40 half-lives have elapsed, the activity A of radionuclide is equal to:
Antworten
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A0/40
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A0/(2*40)
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A0/(2 40)
Frage 63
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Polonium-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?
Frage 64
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What type of radiation can NOT be detected with scintillation detector?
Antworten
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Alpha particles
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Beta Particles
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Gamma Rays
Frage 65
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Ionizing radiation used for "In vivo" radionuclide diagnostics:
Frage 66
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Which quantity is NOT a parameter of radionuclides:
Antworten
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Activity A
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Half-Life T1/2
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Radiation yield
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Decay constant
Frage 67
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Activity A is a parameter of:
Antworten
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Laser radiation
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Radionuclides
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Radioactive sources
Frage 68
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Why is technetium-99m (99mTC) preferred over iodine-131 (131-I) for thyroid gland diagnostics?
Antworten
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99mTC is more cost-effective
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99mTC has fewer side effects
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99mTC is a "pure" gamma source and the radiation is orders of magnitude less
-
Natural deposits of 99mTC exists in some tissues
Frage 69
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1987 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?