Nuclear Medicine Physics and Instrumentation

Flashcards for Nuclear Medicine Physics and Instrumentation

Who discovered radioactivity and in what year?

Henri Becquerel in 1896.

Who discovered radium and in what year?

Marie Curie in 1898.

Who developed the gamma camera and in what year?

Hal Anger in 1958.

What is Electromagnetic Radiation?

The Electromagnetic Spectrum Interaction

What is the formular for photon energy?

E = hν = hc/λ

What does Ionizing radiation do?

Carries enough energy per quantum to remove an electron from an atom or molecule

What are the two categories of ionizing radiation?

Directly ionizing radiation and Indirectly ionizing radiation

What are the three main categories indirectly Ionizing Photon Radiation?

Ultraviolet, X ray and 𝛾 ray

What is the difference between X and 𝛾 rays?

Based on the radiation’s origin

What is Atomic Number (Z)?

Number of protons and number of electrons in an atom

What is Atomic Mass number (A)?

Number of nucleons in an atom = Z + N

What is Electron Binding Energy?

Attractive electric force between the nucleus and electron

What radiation is emitted when Inner shell electron vacancies are filled by outer shell electrons?

Characteristic x-rays, or emission of Auger electrons

What are the classifications of Radiation Quantities and Units?

Dose, Equivalent dose (HT) and Effective dose (E)

What is Activity (A)

Number of nuclear decays per unit time

What are isotopes?

Atoms with same atomic no. (Z)

What are isobars?

Atoms with same atomic mass no. (A)

What are isotones?

Atoms with same neutron no. (N)

What are isomers?

Excited nuclear state that exists for some time

What happens during Radioactive decay?

An unstable nucleus emits particles or photons to transform itself into a more stable nucleus

What is Transmission imgaing?

Anatomical information

What is Emission imaging?

Functional imaging

What are the modes of Radioactive Decay?

Alpha decay (𝛼), Beta decay (𝛽+and 𝛽−) and Gamma decay (𝛾)

What happens during Alpha decay?

Energetic a particle, 4He nucleus (4He2+) isemitted

What happens during Beta minus (𝛽−) decay :

Neutron-rich parent nucleus P Transforms neutron into proton: Ejectse- & antineutrino, which share available energy Daughter D isobar of parent P

What happens during Beta plus (𝛽+) decay :

Proton-rich parent nucleus P Transforms proton into neutron: Ejectse+ & neutrino, which share available energy and Daughter D isobar of parent P

What happens during Electron capture

Nucleus captures an atomic orbital electron (usually K shell) and Daughter D isobar of parent P

What happens during Gamma decay?

A photon of energy being emitted from an unstable nucleus

What is Activity (A)?

disintegration rateat time t (decays/sec)

What is the SI unit of Activity?

1 Bq = 1 disintegrations per second (Becquerel)

What is the Traditional unit of Activity?

1 Ci = 3.7×1010 dps

What is Half-life

The time required for it to decay to 50% of its initial activity level

What are Radionuclides?

Radionuclides Radiation being emitted and Half‐life

What are some medical radionuclides?

50Cr , 98Mo, 132Xe , 90Y and 99mTc

What are the Three methods exists for producing nuclear medicine radionuclides?

Reactor Produced Radionuclide, Accelerator Produced Radionuclide and Radionuclide Generators

Neutron bombardment of stable elements in a nuclear reactor produce radionuclides by what two different reactions?

Neutron capture and Fission

What are the Types of reactor?

Neutron Activation and Nuclear Fission

What are medically important radionuclides produced by fission?

90Y and 99mTc

What Charged particle accelerators are used to accelerate?

Electrically charged particles, such as protons, deuterons (1 2𝐻 nuclei) and 𝛼 particles (2 4𝐻𝑒 nuclei), to very high energies

What are cyclotron Produced Radioisotopes?

SPECT radioisotopes Large cyclotron (30 MeV) and PET radioisotopes Medium cyclotron

What is a Radionuclide generator?

Whenever a radionuclide (parent) decays to another radioactive nuclide (daughter).

What are the Generators used in nuclear medicine?

99Mo- 99mTc , 68Ge- 68Ga , 90Sr- 90Y, 81Rb- 81mKr, 82Sr- 82Rb and 225Ac- 213Bi

What are examples of Charged Particles?

α Particles and β Particles

What are examples of Electromagnetic Radiation?

X-Rays and γ-Ray

What are Photon interactions with matter?

Photoelectric effect, Compton effect and Pair production

What happens during Photoelectric effect?

𝛾 interacts with tightly bound electron, i.e. with whole atom Photon disappears Orbital electron ejected from atom as a photoelectron

What happens during Compton Scattering?

Interaction between 𝛾 with and a loosely bound (“free”) e part of incident E g transferred to “free” orbital electron which is emitted from the atom as the Compton (recoil) electron

What happens during Pair Production?

The incident photon disappears and all of its energy is used to produce an electron-positron pair.

What does Attenuation depend on?

Amount of tissue 𝛾-rays go through and 𝐸𝛾

what is Linear Attenuation Coefficient (µl )?

The actual fraction of photons interacting per unit thickness of material

Whatis Mass Attenuation Coefficient (µm)?

The mass attenuation coefficient is the rate of photon interactions per 1-unit area mass (g/cm2)

What is Half Value Layer?

The thickness of an absorber required to attenuate the intensity of the beam to half its original value

What is Tenth-value layer?

The amount of shielding material required to reduce the radiation intensity to one-tenth of the unshielded value.

What are sensors that produce signals upon interaction with radiation?

Radiation detectors

What are the Radiation detectors in Nuclear Medicine?

Gas filled detectors, Scintillation detectors and Semiconductor detectors

What are the types of Gas filled detectors??

Survey meters, Ionization chamber, Geiger muller and Dose calibrator

What radiation detector uses Gamma Camera ,Well counter, Thyroid probe and Gamma probe?

Scintillation detectors

Radiation detector quality expressed in terms of?

Sensitivity, Energy resolution, Time and position resolution and Counting rate performance

What does a dose calibrator measure?

activity only

What the Two main types of scintillator materials?

Solid Crystals and Liquids

What is scintillator coupled to make a detector?

PMT

What is are the Basic system categories of imaging?

Gamma Camera Systems and Positron Emission Tomography Systems

What are types of Gamma Camera Systems?

Planar gamma cameras (2-D images) and Tomographic systems

Who developed the basic design of the most common type of gamma camera??

Hal Anger in 1957

What are the Basic elements of Gamma Camera?

Collimator, Radiation detector and Computer system

What are Collimators used for?

mechanical lenses, to provide information about the activity on a unique line through the object called the line of response (LOR).

What the major hole shapes are for Collimator?

Round, hexagonal and square

Smaller hole diameters or longer lengths increase the?

resolution of the collimator.

Collimators according to energy range?

Low Energy Collimators, Medium Energy Collimators and High Energy Collimators

What are the most common geometry for collimators?

Parallel, Converging, Diverging and Pinhole

What are examples of radiopharmaceuticals organ agent?

Bone MDP, Brain DTPA, Cardiac MIBI and Kidney DTPA

Categories of Radiopharmaceuticals?

Ready-to-use prepared product, Instant 99mTc kit and Products requiring significant manipulation

What is the ideal Photon energy for Diagnostic Imaging?

100 ~ 200 keV

What is ALARA?

philosophy of radiation use whereby radiation dose is “As Low As Reasonably Achievable”

What are Basic Principles of Radiation Protection?

Planned exposure situations, Emergency exposure situations and Existing exposure situations

What are ICRP Principles of Radiation Protection?

Justification, Optimisation and Limitation of the doses

What are ICRP Recommended Dose Limits?

Occupational and Public

what are Safe working procedures?

Time, Shielding and Distance

To minimize contamination what conditions should be applied?

Adopt clean operating conditions,Prepare radiopharmaceuticals over a drip tray covered with absorbing paper, Adopt good laboratory practices andUse gloves and protective clothing