Deck 25: Diagnostic Nuclear Medicine Imaging

Question 1

Isotopes used in nuclear medicine are called radionuclides.

Answer 1

True

Question 2

In a generator in which a parent isotope is separated from a daughter isotope, once the daughter isotope reaches its maximum level of activity, the activity drops off and the isotope is no longer useful.

Answer 2

False

Question 3

Secular equilibrium means that the daughter isotope decays at the same apparent rate as the parent isotope.

Answer 3

True

Question 4

A nuclear medicine procedure exposes a patient to far more radiation than an X-ray examination because gamma ray photons carry higher energy than X-ray photons.

Question 5

The unit for measuring activity of the radioactive isotope, the becquerel, is equal to 1/s.

Question 6

According to the text, the most important radionuclide used in nuclear medicine today is

A)technetium.
B)barium.
C)uranium.
D)molybdenum.

Question 7

Single-photon emission computed tomography (SPECT) imaging utilizes

A)gamma rays.
B)X-rays.
C)radio waves.
D)radioactive contrast.

Question 8

In a photomultiplier, which of these occurrences is utilized to convert visible photons into electrical pulses?

A)pair production
B)Compton effect
C)photoelectric effect
D)Rayleigh scattering

Question 9

For an isotope with a small decay constant, less time is required to decay than for an isotope with a larger decay constant.

Question 10

In the radioactive decay process, if a parent isotope A decays into a daughter isotope B, and B decays further, what is the rate of change of atoms in sample B?

A)the rate at which A decays minus the rate at which B decays
B)the rate at which A decays plus the rate at which B is produced
C)the rate at which B is produced minus the rate at which B decays
D)the rate at which B is produced plus the rate at which B decays

Question 11

After what length of time does Bi-210 (obtained from Pb-210) reach the maximum of its activity in a generator? The half-life of Bi-210 is 5 days, and that of Pb-210 is 22.6 years.

A)8.99 × 10^-4 d
B)8.99 × 10^-2 d
C)13.9 d
D)53.4 d

Question 12

In the photoelectric effect, which of the following does the number of emitted electrons depend on?

A)the energy of the incoming photons
B)the frequency of the incoming light
C)the amplitude of the incoming light
D)the wavelength of the incoming light

Question 13

When parent isotope A decays into daughter isotope B, what is the relationship between the activities of a parent A_A and a daughter isotope A_B at time t_max, which is the time when the activity of the daughter isotope is maximal?

A)A_A < A_B
B)A_A > A_B
C)A_A = A_B
D)This depends on the isotope.

Question 14

In a gamma camera, how does the energy filter-called the pulse height analyzer-enhance image quality?

A)It uses several cameras around the source to get a 3-D image.
B)It shows all the energies of radiation by intensities, so that we can select only the specific gamma energy released by the isotope.
C)Only the specific gamma radiation released by the isotope is allowed to pass, eliminating all other gamma radiation, such as cosmic rays and radiation of terrestrial origin.
D)It allows only gamma radiation to pass, and later we select the specific energy released by the isotope.

Question 15

Which of the following methods is a functional imaging method?

A)X-ray imaging
B)ultrasound imaging
C)nuclear medicine
D)Infrared imaging

Question 16

The total charge emitted in the photoelectric effect from a metal surface is proportional to the number of incoming photons of the light.

Question 17

What is the condition for secular equilibrium between parent and daughter isotopes?

A)The half-life of a parent isotope is much longer than the half-life of a daughter isotope.
B)The half-life of a parent isotope is much shorter than the half-life of a daughter isotope.
C)The half-life of a parent isotope must be equal to the half-life of a daughter isotope.
D)The half-life of a parent isotope is very close to the half-life of a daughter isotope.

Question 18

In which of these types of machinery are the positron-emitting isotopes used in PET produced?

A)in cyclotrons, particle accelerators
B)in fission nuclear reactors
C)in fusion nuclear reactors
D)in special nuclear reactors made for antimatter production

Question 19

After what length of time does Tc-99m (obtained from Mo-99) reach the maximum of its activity in a generator? The half-life of Tc-99m is 6.02 h, and that of Mo-99 is 66.7 h.

A)3.96 × 10^-4 d
B)3.96 × 10^-2 d
C)19.1 d
D)22.9 d

Question 20

In a generator where the parent isotope is separated from the daughter isotope, when is the separation most efficient?

A)at the maximum level of activity of the parent isotope
B)at the maximum level of activity of the daughter isotope
C)at the minimum level of activity of the daughter isotope
D)It depends on the isotope.

Question 21

Describe briefly the functions of the gamma camera.

Question 22

A gamma camera is used to examine the rates at which radionuclides are accumulated in or eliminated from an organ.

Question 23

Describe briefly the function of a pulse height analyzer in a gamma camera.

Question 24

A cyclotron with a proton current of I = 2 × 10¹⁴ protons/s is used to irradiate a target with n = 3 × 10²⁰ neutrons in order to produce N-13 (T_1/2 = 10 min). The cross-section for the reaction is ó = 3 × 10^-26 cm². Calculate the number of N-13 nuclei after 30 minutes of irradiation.

Question 25

Describe the photoelectric effect and its use in nuclear imaging.

Question 26

A cyclotron with a proton current of I = 1.5 × 10¹⁴ protons/s is used to irradiate a target with n = 10¹⁸ neutrons/cm² in order to produce C-11 (T_1/2 = 20 min). The cross-section for the reaction is ó = 3 × 10^-26 cm². Calculate the activity after one hour of irradiation.

Question 27

The number of visible light photons produced from gamma radiation is proportional to the energy of the original incoming gamma ray.

Question 28

What is the ratio of Bi-210 to Pb-210 activities at secular equilibrium? The half-life of Bi-210 is 5 days, and that of Pb-210 is 22.6 years.

Question 29

What is the limitation of a standard gamma camera, and which method is used to overcome this limitation?

Question 30

The gamma camera produces a three-dimensional image from various angles.

Question 31

Describe the two steps of radiation detection in nuclear medicine.

Question 32

¹³¹I is used in a scan. If its half-life is 8.1 days, how long will it take for its activity to drop to 1% of its initial value?

Question 33

In thyroid scans, ¹²³I is used. Its daughter nucleus is stable. How long will it take until the amount of ¹²³I left is 5% of the original amount? The half-life of ¹²³I is 13 hours.

Question 34

How is technetium used in the diagnosis of metastatic deposits in bones in some forms of cancer?