CLUSTER 5
187 Questions
0 Views

CLUSTER 5

Created by
@CheapestArtNouveau

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary delivery method for the tracer used in nuclear medicine procedures?

  • Topical application
  • Injection (correct)
  • Oral ingestion
  • Inhalation

    • Which of the following radioisotopes is most commonly used for diagnosing cancer and infections?

  • I-131
  • I-123
  • Tc-99m (correct)
  • Co-60

    • In the context of nuclear medicine, what does the term 'localization' refer to?

  • The radioactive decay of the tracer over time
  • The accumulation of the tracer in specific organs or tissues (correct)
  • The process of administering medication through a vein
  • The use of radionuclides for therapeutic purposes

    • What is the main role of a nuclear medicine technologist?

    <p>To perform tests and operate nuclear medicine equipment</p> Signup and view all the answers

    Which type of radiation is primarily emitted by radionuclides used in diagnostic procedures?

    <p>Gamma radiation</p> Signup and view all the answers

    What is a key factor affecting radionuclide dosage in therapeutic procedures?

    <p>Patient weight and body surface area</p> Signup and view all the answers

    What is the fundamental building block of matter as described in nuclear physics?

    <p>Atom</p> Signup and view all the answers

    Which radioisotope is specifically noted for its use in targeted radiotherapy?

    <p>Zevalin (Y-90)</p> Signup and view all the answers

    Cyclotron production of isotopes is primarily used to create which type of radioactive materials?

    <p>Short-lived isotopes for diagnostic imaging</p> Signup and view all the answers

    What does the term 'emission' refer to in the context of nuclear medicine?

    <p>The gamma ray emissions from the tracer in the body</p> Signup and view all the answers

    What is the process by which an unstable atom emits radiation to become more stable?

    <p>Radioactive decay</p> Signup and view all the answers

    Which decay mode involves the emission of a helium nucleus?

    <p>Alpha decay</p> Signup and view all the answers

    What is the significance of half-life in radioactive decay?

    <p>Time required for half of the radioactivity to decay</p> Signup and view all the answers

    What type of transition involves the nucleus emitting a gamma photon?

    <p>Isomeric transition</p> Signup and view all the answers

    Which decay mode is characterized by a neutron transforming into a proton?

    <p>Beta minus decay</p> Signup and view all the answers

    What is a key characteristic of alpha particles?

    <p>Most ionizing and least penetrating</p> Signup and view all the answers

    What does internal conversion in decay indicate?

    <p>Transferring excess energy to an outer shell electron</p> Signup and view all the answers

    During which decay mode does the atomic number remain unchanged?

    <p>Gamma decay</p> Signup and view all the answers

    In biological half-life, what is primarily being measured?

    <p>Time required for a radioactive substance to reduce by half in a biological system</p> Signup and view all the answers

    What occurs during gamma decay?

    <p>Excess energy is released as gamma rays</p> Signup and view all the answers

    What is the primary purpose of Bexxar Therapy?

    <p>Treatment of certain non-Hodgkin’s lymphomas</p> Signup and view all the answers

    Which therapeutic pharmaceutical is indicated for the treatment of hyperthyroidism?

    <p>Iodine 131 Nal</p> Signup and view all the answers

    What characteristic of a radiopharmaceutical is essential for effective PET imaging?

    <p>Emits positron particles</p> Signup and view all the answers

    Which factor is not typically considered in determining radionuclide dosage for therapeutic applications?

    <p>Dose administered in diagnostic imaging</p> Signup and view all the answers

    What is the main function of a cyclotron in radionuclide production?

    <p>To accelerate charged particles</p> Signup and view all the answers

    Which of the following describes the ideal characteristics of a radionuclide for diagnostic imaging?

    <p>Short physical half-life and suitable energy emissions</p> Signup and view all the answers

    Which radionuclide is most commonly used in clinical applications due to its qualities?

    <p>Tc-99m</p> Signup and view all the answers

    Which of the following methods is not typically used for elution in radionuclide generation?

    <p>Aeration</p> Signup and view all the answers

    What is a significant advantage of using radionuclide generators?

    <p>They provide a continuous supply of short-lived isotopes</p> Signup and view all the answers

    What principle does the radioactive decay of parent radionuclides in generators rely on?

    <p>Isobaric transition</p> Signup and view all the answers

    Which form of radiopharmaceutical is used in renal dynamic scintigraphy?

    <p>Tc-99m pertechnetate</p> Signup and view all the answers

    Which element is a parent radionuclide that decays into Tc-99m?

    <p>Mo-99</p> Signup and view all the answers

    What is a unique emission characteristic of Tc-99m compared to its parent Tc-99?

    <p>Emits a monoenergetic gamma photon</p> Signup and view all the answers

    Which of the following distinguishes therapeutic radiopharmaceuticals from diagnostic ones?

    <p>They are designed to deliver higher doses to targeted tissues</p> Signup and view all the answers

    Which process is typically used to prepare radpharmaceuticals in nuclear medicine?

    <p>Heating in a water bath</p> Signup and view all the answers

    What is the effect of a narrow beam width on spatial resolution?

    <p>It provides better spatial resolution</p> Signup and view all the answers

    Which component is NOT part of spatial resolution?

    <p>Temporal Resolution</p> Signup and view all the answers

    How does the temporal resolution of an imaging system change with an increased frame rate?

    <p>It improves</p> Signup and view all the answers

    What is the role of backing or damping materials in ultrasonic imaging?

    <p>To reduce unwanted vibrations</p> Signup and view all the answers

    What does the Doppler effect describe in ultrasound imaging?

    <p>Change in echo frequency due to movement</p> Signup and view all the answers

    Which statement about thick physical housing in ultrasound systems is true?

    <p>It acts as an acoustic insulator</p> Signup and view all the answers

    The ability of an imaging system to display two structures close together as separate images is referred to as:

    <p>Spatial resolution</p> Signup and view all the answers

    Which type of resolution is primarily concerned with differentiating between gray shades in body tissues?

    <p>Contrast resolution</p> Signup and view all the answers

    What is the effect of high-frequency ultrasound on spatial resolution?

    <p>It enhances resolution</p> Signup and view all the answers

    What does a two-dimensional image represent in terms of slice thickness?

    <p>A single dimension of a three-dimensional volume</p> Signup and view all the answers

    What is the main cause of edge shadowing in ultrasound imaging?

    <p>Highly attenuating structures</p> Signup and view all the answers

    What does anechoic mean in the context of ultrasound imaging?

    <p>Absence of echoes</p> Signup and view all the answers

    How does beam width artifact affect ultrasound imaging?

    <p>Causes loss of detail at the edge of structures</p> Signup and view all the answers

    What is the primary factor that influences slice thickness artifact?

    <p>Beam angulation</p> Signup and view all the answers

    What effect do side lobes have on ultrasound imaging?

    <p>Cause artifacts leading to false diagnoses</p> Signup and view all the answers

    What does the Ankle/Brachial Index (ABI) measure?

    <p>Ratio of ankle pressure to brachial pressure</p> Signup and view all the answers

    Which of the following describes axial resolution in ultrasound?

    <p>Ability to distinguish two structures along a path parallel to the sound beam</p> Signup and view all the answers

    What is the function of color flow Doppler in ultrasound imaging?

    <p>Quantify velocity of blood flow by coloring pixels</p> Signup and view all the answers

    What is the main purpose of a converging collimator?

    <p>To provide some magnification</p> Signup and view all the answers

    Which component of the gamma camera is responsible for converting light into electrical pulses?

    <p>Photomultiplier tube (PMT)</p> Signup and view all the answers

    How do diverging collimators differ from converging collimators?

    <p>Their holes are angled opposite to the direction of converging collimators</p> Signup and view all the answers

    What type of collimator uses a single 2-5 mm hole?

    <p>Pinhole collimator</p> Signup and view all the answers

    What is the primary function of the scaler/timer in a gamma camera?

    <p>To measure and record the event times</p> Signup and view all the answers

    What happens to the image as the source is moved further away from a pinhole collimator?

    <p>The image gets smaller</p> Signup and view all the answers

    Which component of the gamma camera provides an image of the radionuclide injected into the patient?

    <p>Collimator</p> Signup and view all the answers

    Which type of collimator combines parallel and converging methods?

    <p>Fan beam collimator</p> Signup and view all the answers

    What role does a physicist play in nuclear medicine?

    <p>Managing the technology and equipment used in nuclear medicine</p> Signup and view all the answers

    Which method is NOT typically used for administering a tracer in nuclear medicine?

    <p>Sublimation</p> Signup and view all the answers

    What is the primary action involved in the localization phase of nuclear medicine?

    <p>Targeting specific organs or tissues with a tracer</p> Signup and view all the answers

    Which of the following best defines particulate radiation?

    <p>Radiation composed of particles like alpha and beta rays</p> Signup and view all the answers

    What is the function of a gamma camera in nuclear medicine?

    <p>To detect gamma emissions from a tracer in the body</p> Signup and view all the answers

    Which statement about nuclear medicine physicians is accurate?

    <p>They are licensed to use radioactive materials.</p> Signup and view all the answers

    What key aspect characterizes the emission phase in nuclear medicine procedures?

    <p>Gamma rays are emitted from the specific organ being studied.</p> Signup and view all the answers

    What does the nucleon binding force accomplish within an atomic nucleus?

    <p>Holds the atomic nucleus together</p> Signup and view all the answers

    What differentiates in vivo from in vitro analysis in nuclear medicine?

    <p>In vivo involves examination of living bodies.</p> Signup and view all the answers

    Which of the following is NOT a common diagnostic procedure in nuclear medicine?

    <p>Physical examination of internal organs</p> Signup and view all the answers

    What type of resolution does a shorter spatial pulse improve in continuous wave Doppler?

    <p>Axial resolution</p> Signup and view all the answers

    What is a key limitation of pulsed wave Doppler when measuring blood velocities?

    <p>Cannot measure high blood velocities in deep vessels</p> Signup and view all the answers

    How does lateral resolution depend on beam width in ultrasound imaging?

    <p>Narrower beam width leads to better lateral resolution</p> Signup and view all the answers

    What principle does color Doppler utilize to display flow velocities?

    <p>Frequency modulation</p> Signup and view all the answers

    What type of interaction occurs when sound waves strike boundaries between materials with different tissue properties?

    <p>Reflection</p> Signup and view all the answers

    What phenomenon occurs when an ultrasound wave strikes an object equal to or smaller than its wavelength?

    <p>Scattering</p> Signup and view all the answers

    What is the main cause of attenuation in ultrasound waves as they pass through tissues?

    <p>Absorption</p> Signup and view all the answers

    What occurs during acoustic shadowing in ultrasound imaging?

    <p>Decreased signal intensity behind strong reflectors</p> Signup and view all the answers

    How does focusing affect ultrasound imaging resolution?

    <p>Improves overall image quality</p> Signup and view all the answers

    What is the role of the Time-gain-compensation (TGC) amplifier in ultrasound?

    <p>Compensate for tissue attenuation</p> Signup and view all the answers

    What is one characteristic of ultrasound artifacts?

    <p>They appear as structures not reflective of actual tissues</p> Signup and view all the answers

    What occurs during the phenomenon of reverberation in ultrasound imaging?

    <p>Production of spurious echoes due to repeated reflection</p> Signup and view all the answers

    What is the typical speed of ultrasound propagation in soft tissues?

    <p>1540-4620 m/s</p> Signup and view all the answers

    How does increasing the frequency of ultrasound waves affect absorption?

    <p>Increases absorption</p> Signup and view all the answers

    What type of transducer provides a wide field of view and is best suited for abdominal and obstetric scanning?

    <p>Sector/curvilinear array transducer</p> Signup and view all the answers

    Which effect describes the conversion of mechanical energy into electrical energy in ultrasound technology?

    <p>Inverse piezoelectric effect</p> Signup and view all the answers

    The impedance matching layer in an ultrasound transducer serves to enhance what aspect?

    <p>Transmission into the body</p> Signup and view all the answers

    Which type of transducer is characterized by a flat face and is used primarily in cardiac ultrasound?

    <p>Phased array transducer</p> Signup and view all the answers

    What parameter determines lateral resolution in ultrasound imaging?

    <p>Width of the beam</p> Signup and view all the answers

    What is the primary characteristic of a large piezo crystal diameter in ultrasound applications?

    <p>Increased divergence of the beam</p> Signup and view all the answers

    Which feature is typical of a transducer with a small crystal diameter?

    <p>Improved axial resolution</p> Signup and view all the answers

    What is the purpose of an acoustic lens in an ultrasound transducer?

    <p>Control lateral resolution</p> Signup and view all the answers

    Which statement best describes the concept of bandwidth in ultrasound technology?

    <p>The range of frequencies contained within an ultrasound pulse</p> Signup and view all the answers

    The near field of an ultrasound beam is characterized by which feature?

    <p>Greater resolution</p> Signup and view all the answers

    What is the primary function of a gamma camera in nuclear medicine?

    <p>To transform radioactive emissions into images</p> Signup and view all the answers

    Which statement best describes radionuclide therapy?

    <p>It utilizes radioactive materials for therapeutic purposes</p> Signup and view all the answers

    What does the term 'tracers' refer to in nuclear medicine?

    <p>Radioactive drugs used in diagnostic procedures</p> Signup and view all the answers

    What occurs when ultrasound energy is lost to tissue energy and converted into thermal energy?

    <p>Absorption</p> Signup and view all the answers

    Who is considered the father of nuclear medicine?

    <p>Georg Charles de Hevesy</p> Signup and view all the answers

    What determines the reflection of an ultrasound wave at the boundary between two media?

    <p>Acoustic impedance difference</p> Signup and view all the answers

    What is one characteristic of a radionuclide used in therapeutic applications?

    <p>It must have appropriate energy levels for treating diseases</p> Signup and view all the answers

    Which branch of nuclear medicine focuses on utilizing radioactive materials for diagnosis and therapy?

    <p>Nuclear imaging</p> Signup and view all the answers

    Which of the following materials is NOT typically a piezoelectric crystal used in transducers?

    <p>Copper</p> Signup and view all the answers

    What happens to the ultrasound beam when it encounters two media with the same acoustic impedance?

    <p>100% energy is transmitted</p> Signup and view all the answers

    What type of information can a gamma camera record in nuclear medicine?

    <p>Physiologic and pathophysiologic information</p> Signup and view all the answers

    What describes the behavior of sound waves when they strike a boundary and some return to the source?

    <p>Reflection</p> Signup and view all the answers

    What is the primary focus of therapeutic procedures in nuclear medicine?

    <p>Treatment of diseases using radioactive substances</p> Signup and view all the answers

    Which type of scattering occurs due to interaction with smaller reflectors?

    <p>Rayleigh scattering</p> Signup and view all the answers

    What is the primary characteristic of a high-density substance in terms of acoustic impedance?

    <p>It has high acoustic impedance</p> Signup and view all the answers

    In terms of ultrasound energy propagation, what does the term 'refraction' refer to?

    <p>Change in direction of the beam</p> Signup and view all the answers

    What occurs when the difference in acoustic impedance between two materials is high?

    <p>High chance of reflection</p> Signup and view all the answers

    What does the piezoelectric effect describe in relation to ultrasound transducers?

    <p>Conversion of electrical energy into mechanical energy</p> Signup and view all the answers

    What is the purpose of the photodiode in a detector array?

    <p>To detect and convert light into an electrical signal</p> Signup and view all the answers

    Which characteristic is NOT associated with gas-filled detectors?

    <p>Requires a constant power supply</p> Signup and view all the answers

    In which imaging technique is the plane of the image perpendicular to the long axis of the body?

    <p>Axial tomography</p> Signup and view all the answers

    What does geometric efficiency refer to in detector systems?

    <p>The sensitive area of detectors relative to total exposed area</p> Signup and view all the answers

    What is the primary purpose of a scintillation detector?

    <p>To convert radiation into an electrical signal</p> Signup and view all the answers

    What aspect does quantum efficiency measure in a detector?

    <p>The fraction of incident X-rays absorbed and contributing to the signal</p> Signup and view all the answers

    What is an advantage of high scatter suppression in detector systems?

    <p>Reduces background noise and enhances image clarity</p> Signup and view all the answers

    Which component has the highest cooling rate in a spiral CT system?

    <p>Anode head</p> Signup and view all the answers

    What does dose efficiency represent in a detector?

    <p>The product of geometric, quantum, and conversion efficiencies</p> Signup and view all the answers

    Which is true about the life expectancy of tubes in conventional CT machines?

    <p>They last for approximately 5000 exposures</p> Signup and view all the answers

    What defines the stopping power of a detector material?

    <p>The amount of energy lost by radiation passing through</p> Signup and view all the answers

    Which statement accurately describes the first CT scan machine?

    <p>It involved 180 translations and 1 degree of rotation</p> Signup and view all the answers

    What is the typical range for overall dose efficiency values in detectors?

    <p>Between 0.45 and 0.85</p> Signup and view all the answers

    What happens during beta plus decay?

    <p>A proton is converted into a neutron and a positron.</p> Signup and view all the answers

    What is primarily produced during electron capture?

    <p>A neutron and a neutrino.</p> Signup and view all the answers

    What role do radionuclides play in radiopharmaceuticals?

    <p>They determine the biodistribution and behavior in the body.</p> Signup and view all the answers

    Which isotope is primarily used for thyroid function diagnosis?

    <p>Iodine-131</p> Signup and view all the answers

    What is the half-life of Nitrogen-13 typically used for?

    <p>10 minutes for myocardial perfusion imaging.</p> Signup and view all the answers

    Which of the following is not typically used in radiolabeling?

    <p>Cacao Butter</p> Signup and view all the answers

    What is the significance of gamma emitters in radiopharmaceuticals?

    <p>They allow for external detection and measurement post-administration.</p> Signup and view all the answers

    In the context of imaging, what does the term 'biodistribution' refer to?

    <p>The distribution of the agent throughout the body.</p> Signup and view all the answers

    Which property distinguishes alpha decay from beta decay?

    <p>Alpha decay decreases the atomic mass by 4.</p> Signup and view all the answers

    What is the function of biologically active molecules in radiopharmaceuticals?

    <p>To serve as a tracer and determine biodistribution.</p> Signup and view all the answers

    Which compound is commonly used for myocardial perfusion imaging?

    <p>Technetium-99m</p> Signup and view all the answers

    Which of the following is a common characteristic of radionuclides used in diagnostic imaging?

    <p>They must not emit alpha particles.</p> Signup and view all the answers

    What diagnostic purpose does Technetium-99m serve?

    <p>Cardiovascular imaging.</p> Signup and view all the answers

    What is a key feature of cobalt-57 used in medical imaging?

    <p>It is used to assess RBC volume.</p> Signup and view all the answers

    Which radionuclide is known for its rapid decay time?

    <p>Fluorine-18</p> Signup and view all the answers

    What does the term 'hyperechoic' refer to in ultrasound imaging?

    <p>Producing more echoes than normal</p> Signup and view all the answers

    Which transducer is specifically designed for high-frequency imaging inserted into the rectum?

    <p>Endorectal transducer</p> Signup and view all the answers

    Which layer of a blood vessel is referred to as the intima?

    <p>Inner layer of the vessel</p> Signup and view all the answers

    What does the term 'ischemia' describe in a cardiac context?

    <p>Damage due to blood supply disruption</p> Signup and view all the answers

    Which term describes structures that appear nearly the same in texture as their surrounding tissue?

    <p>Isoechoic</p> Signup and view all the answers

    What is lateral resolution in ultrasound imaging?

    <p>Ability to distinguish two structures lying perpendicular to the sound beam</p> Signup and view all the answers

    What is the primary characteristic of a leiomyoma?

    <p>It is the most common benign tumor</p> Signup and view all the answers

    What does the term 'embryo' refer to during early development?

    <p>A developing zygote through the 10th week of gestation</p> Signup and view all the answers

    What is the definition of 'gestational age'?

    <p>The length of time from the first day of the last menstrual period</p> Signup and view all the answers

    What describes a 'follicular cyst'?

    <p>A functional ovulatory cyst with an ovum</p> Signup and view all the answers

    Which statement best defines 'posterior acoustic shadowing'?

    <p>Reduction in reflection amplitude from strongly reflecting structures</p> Signup and view all the answers

    What does 'phasic flow' refer to in venous circulation?

    <p>Normal venous respiratory variations in blood flow</p> Signup and view all the answers

    How is the 'piezoelectric effect' best described?

    <p>Conversion of pressure to electrical voltage</p> Signup and view all the answers

    What does 'heterogeneous' refer to in a medical context?

    <p>Having a mixed composition of tissues or cells</p> Signup and view all the answers

    Which of the following best describes 'non-invasive techniques'?

    <p>Methods that do not break the skin or enter cavities</p> Signup and view all the answers

    What is the main purpose of the myometrium in the uterus?

    <p>To provide a thick muscular layer for uterine contractions</p> Signup and view all the answers

    What is the primary purpose of a gamma camera in nuclear medicine?

    <p>To transform emissions into images for diagnosis</p> Signup and view all the answers

    Which of the following best describes a tracer in nuclear medicine?

    <p>A radioactive substance that provides physiological information</p> Signup and view all the answers

    What specific condition may be treated using radionuclide therapy?

    <p>Benign diseases such as hyperthyroidism</p> Signup and view all the answers

    Which of the following described the father of nuclear medicine?

    <p>Georg Charles de Hevesy</p> Signup and view all the answers

    What type of information do scintillation cameras provide?

    <p>Physiologic or pathophysiologic images</p> Signup and view all the answers

    What is the role of radionuclides in therapeutic procedures?

    <p>To provide targeted treatment via radioactivity</p> Signup and view all the answers

    Which of the following best defines scattering in the context of ultrasound imaging?

    <p>Diffusion of sound in multiple directions upon encountering particles</p> Signup and view all the answers

    What is the significance of Hal Anger's contribution to nuclear medicine?

    <p>He created the gamma camera</p> Signup and view all the answers

    What is the main purpose of scintillation detectors in nuclear medicine?

    <p>To flash light when ionization particles pass through crystals</p> Signup and view all the answers

    Which imaging technique relies on phagocytosis for visualization in nuclear medicine?

    <p>Antigen-antibody tumor imaging</p> Signup and view all the answers

    What factor does NOT affect the geometric efficiency of collimators in scintillation detectors?

    <p>Type of scintillation crystal used</p> Signup and view all the answers

    In the context of active transport imaging, which of the following organs is primarily assessed?

    <p>Kidneys</p> Signup and view all the answers

    What is a key functional difference between survey meters and Geiger-Muller counters?

    <p>Geiger-Muller counters can measure contamination levels</p> Signup and view all the answers

    What is the role of receptor binding in adrenal medullary imaging?

    <p>To analyze hormonal activity in the adrenal glands</p> Signup and view all the answers

    Which of the following best describes how scintillation detectors measure the energy distribution of particles?

    <p>By detecting pulses of light emitted from ionized crystals</p> Signup and view all the answers

    What aspect of collimators contributes most to their geometric efficiency?

    <p>Arrangement of holes</p> Signup and view all the answers

    What do gas-filled detectors primarily rely on for their operation?

    <p>Ionization of gas</p> Signup and view all the answers

    Which of the following is a key factor determining detector efficiency?

    <p>Geometric efficiency</p> Signup and view all the answers

    What is the primary purpose of a photodiode in the context of detectors?

    <p>To convert light into an electrical signal</p> Signup and view all the answers

    What imaging advantage does a small focal spot provide in computed tomography?

    <p>Higher spatial resolution</p> Signup and view all the answers

    How does the term 'conversion efficiency' relate to detectors?

    <p>It indicates the ability to convert an absorbed x-ray signal to an electrical signal.</p> Signup and view all the answers

    What does overall dose efficiency indicate in a detector?

    <p>The product of geometric, quantum, and conversion efficiency.</p> Signup and view all the answers

    Which component contributes to heat dissipation in a computed tomography machine?

    <p>High speed rotors</p> Signup and view all the answers

    What is the general function of scintillation detectors?

    <p>To absorb radiation and produce light</p> Signup and view all the answers

    What was significant about the EMI scanner in the development of imaging technology?

    <p>It was the first CT scan machine.</p> Signup and view all the answers

    In computed tomography imaging, what does the plane of the image refer to?

    <p>The orientation of the image with respect to the body.</p> Signup and view all the answers

    What is the result of high scatter suppression in detectors?

    <p>Improved image clarity and accuracy.</p> Signup and view all the answers

    What occurs during the process of anode cooling in a CT machine?

    <p>The anode is heated by the x-ray tube.</p> Signup and view all the answers

    What characteristic defines conventional/axial tomography?

    <p>The image plane is parallel to the long axis of the body.</p> Signup and view all the answers

    What role does the anode head capacity play in CT imaging?

    <p>It affects the machine's heat dissipation.</p> Signup and view all the answers

    Study Notes

    Nuclear Medicine

    • Bq as a unit for disintegration per second (dps)
    • Half-life is the time required for radioactivity to decrease to half its initial value
    • Biological half-life is the time for half the amount of a substance to be eliminated from the body
    • Radioactive decay involves the spontaneous emission of radiation from an unstable atom (parent) to reach a more stable state (daughter).
    • There are key conservation laws that apply:
      • Conservation of energy
      • Conservation of mass number
      • Conservation of electric charge
    • Types of transition in radioactive decay:
      • Isomeric transition: Rearrangement of protons and neutrons into the lowest energy state, with excess energy released as a gamma photon
      • Isobaric transition: Nuclear transformation

    Modes of Decay

    • Alpha decay:
      • Proton and neutron rich
      • Emission of alpha particle - most ionizing and destructive, least penetrating.
      • Alpha particles are helium nucleus (2 protons and 2 neutrons).
    • Beta minus decay:
      • Neutron rich
      • Emission of negatron and an antineutrino
      • Neutron converts into a proton, an electron (negatron) and an antineutrino.
    • Electron capture:
      • Excited nucleus transfers excess energy to an inner shell electron.
      • The electron is ejected from the atom (if excess energy is greater than binding energy), resulting in conversion electron.
      • Filling of the vacancy creates a characteristic x-ray and a free electron.
    • Gamma decay:
      • Excess energy in the nucleus is released in the form of gamma rays (photons).
      • No change in atomic number.
      • Can occur directly (from excited nuclear state) or after other decays (alpha or beta).

    Radiopharmaceuticals

    • Thallium chloride (CF-201): Used for myocardial imaging, half-life of 73.5 hrs.
    • Xenon (133Xe): Used for lung ventilation imaging, half-life of 5.3 days, CF is Xenon gas.
    • Iodine-131 (131I): Used for thyroid cancer and hyperthyroidism treatment.
    • Strontium-89 chloride (89Sr) and Samarium-153 lexidronam (153Sm): Used for pain relief from cancer that is metastatic to bone.
    • Iodine-131 and Yttrium-90 (90Y) labeled monoclonal antibodies: used for treating certain non-Hodgkin's lymphomas
    • Phosphorus-32 (32P) as sodium phosphate: Used for bone marrow disorders such as polycythemia vera.
    • Main component of a radiopharmaceutical:
      • Radioactive molecule to allow monitoring of distribution and detection externally through imaging devices.

    Ideal Radiopharmaceutical

    • Ideal pharmaceutical:
      • Short biological half-life
      • Minimal side effects
      • Localizes quickly and precisely
    • Ideal radionuclide:
      • Short physical half-life
      • Pure gamma emitter
      • Easy to prepare
      • Labeling stability
      • Energy: 100-200 keV
      • Readily available
      • Suitable for incorporating into a pharmaceutical

    Design Characteristics of Radiopharmaceuticals

    • Decay in gamma emissions:
      • Suitable energy: 100-300 keV, ideal for gamma cameras
      • Sufficient abundance of emissions for detection
    • No particulate emissions/radiation:
      • Increases patient radiation dose
      • Does not contribute to diagnostic information
    • Beta emissions:
      • Used primarily for therapeutic radiopharmaceuticals due to higher energy and greater tissue damage
    • Optimal effective half-life:
      • Long enough for intended application
      • Typically a few hours
      • High specific activity
      • Prevents toxic effects to the patient

    Technetium-99m (Tc-99m)

    • Most commonly used radionuclide
    • Readily available
    • Favorable energy: 140 keV
    • Monoenergetic gamma photon (consistent energy)
    • Favorable dosimetry: lacks primary particulate radiations
    • Ideal half-life: 6 hours, good balance for many imaging studies
    • Advantages:
      • Short half-life: Reduces patient radiation exposure
      • Pure gamma emitter: Good for imaging
      • High specific activity: Improved resolution
      • High stability: Minimizes disintegration during preparation and administration
      • Multiple forms: Can be incorporated into various radiopharmaceuticals for different applications

    Technetium-99m (Tc-99m) vs Technetium-99 (Tc-99)

    • Tc-99m:
      • Half-life: 6 hours
      • Emits: Gamma radiation
      • Decay product of Mo-99 (molybdenum-99): Through isobaric transition
    • Tc-99:
      • Half-life: 211,000 years (long-lasting)
      • Emits: Beta particulate radiation
      • Decay product of U-235 (uranium-235): Through fission

    Forms of Technetium-99m:

    • Tc-99m pertechnetate (99mTcO4-): Common form in the body, both the radionuclide and the pharmaceutical component.
      • Can be used for thyroid imaging, brain scans, and gastrointestinal studies
    • Tc-99m-labeled radiopharmaceuticals: Examples include:
      • Mebrofenin (Hepatolite): Used for liver imaging.
      • MAG3 (mercaptoacetyltriglycine): Used for kidney function studies.
      • Bicisate (Ceretec): Used for brain perfusion studies.
      • Disofenin (Hepatolite): Used for liver imaging.
      • Diethylenetriamine-pentaacetic acid (DTPA): Used renal dynamic scintigraphy, lung ventilation studies, thyroid cancer and hepatocellular carcinoma imaging.

    Iodine-131 (131I)

    • Used for thyroid imaging and treatment.
      • Often used for thyroid cancer and hyperthyroidism

    Nuclear Medicine Procedures

    • Diagnostic Procedures:
      • Use radioactive materials to test body functions.
      • Common radioisotopes: Tc-99m and F-18 (fluorine-18).
    • In Vitro Procedures:
      • Analyze samples outside the body.
      • Detecting gamma-emitting radionuclides in urine and feces.
    • In Vivo Procedures:
      • Examine the living body.
      • Use gamma camera to detect gamma-emitting radionuclides introduced into the body.
        • Common methods: injection of a radiopharmaceutical.

    Nuclear Physics

    • Atom:
      • Fundamental building block of matter.
      • Smallest part of an element with all the properties of that element.
    • Nucleus:
      • Positively charged central part of the atom.
      • Contains most of the atom's mass.
      • Composed of nucleons (protons and neutrons).
      • Forces:
        • Repulsive force: Between protons due to similar charges.
        • Nucleon binding force: Holds the atomic nucleus together.
    • Electron cloud:
      • System of electrons revolving around the nucleus.
      • Exists in discrete energy levels.

    Particulate Radiation

    • Alpha particles:
      • Composed of 2 protons and 2 neutrons.
      • Highly ionizing and destructive, but least penetrating.
    • Beta particles:
      • Electrons (negatrons or positrons)
      • Moderately ionizing and penetrating.
    • Gamma rays:
      • High energy electromagnetic radiation.
      • Highly penetrating, with low ionizing power.
    • Neutron radiation:
      • Composed of neutrons.
      • High penetrating power, good for neutron activation.

    Continuous Wave Doppler

    • Uses continuous ultrasound waves.
    • Provides accurate measurement of high velocities.
    • Lacks depth resolution.
    • Uses spatial pulse length and wavelength to distinguish objects parallel to the beam.

    Pulsed Wave Doppler

    • Transmits ultrasound pulses allowing for depth resolution.
    • Measures blood flow speed within a specific vessel.
    • Unable to accurately measure high velocities in deeper vessels.
    • High velocities can be incorrectly displayed as low velocities.

    Lateral Resolution

    • Ability to distinguish objects perpendicular to the ultrasound beam.
    • Depends on the beam diameter.
    • Narrower beam width provides better lateral resolution.

    Colour Doppler

    • Displays different blood flow velocities in different colours.

    Duplex Doppler System

    • Directs the Doppler beam accurately towards specific blood vessels.

    Wave Propagation

    • Transmission and spread of ultrasound waves through tissues.
    • Soft tissues have an average propagation speed of 1540-4620 m/s.

    Wavelength

    • Length of a single cycle of the ultrasound wave.
    • Determines the scanner's resolution.

    Focusing

    • Adjustment of the ultrasound beam to improve resolution.
    • Can be electronic or achieved using a lens attached to the transducer.

    Amplification

    • Compensates for ultrasound attenuation using the Time-gain-compensation (TGC) amplifier.
    • Improves the quality of the final image.

    Ultrasound Interactions and Attenuations

    • Attenuation: Decrease in ultrasound wave intensity and amplitude as they pass through tissue.
    • Absorption: Conversion of ultrasound energy into heat, a major contributor to attenuation.

    Absorption

    • Higher frequencies result in greater absorption.
    • Bone has a higher absorption coefficient, increasing with protein content.

    Reflection

    • Occurs at interfaces between structures with significantly different acoustic impedance.

    Scattering

    • Occurs when ultrasound waves encounter objects smaller than the wavelength.

    Refraction

    • Beam deviation at an oblique angle interface between tissues with different wave velocities.

    Divergence

    • Beam spread due to diffraction as it travels through tissue.

    Ultrasound Artifacts

    • Image structures that do not represent the actual tissues being scanned.

    Reverberation

    • False echoes caused by repeated reflections between high impedance interfaces (Comet tail artifact).

    Acoustic Shadowing

    • Occurs behind highly attenuating structures, creating a shadow.

    Acoustic Enhancement

    • Occurs behind weakly attenuating structures, resulting in increased brightness behind the structure.

    Edge Shadowing

    • Combination of refraction and reflection at rounded structure edges.

    Beam Width Artifact

    • Echoes from side lobes are mistakenly attributed to the central axis of the main lobe.

    Slice Thickness Artifact

    • False echoes due to the beam's thickness, dependent on beam angulation.

    Side Lobe Artifact

    • False echoes generated by side lobes, affecting lateral resolution.

    Contrast Resolution

    • Ability to distinguish between tissues and display them as different shades of gray.
    • Optimized by using the correct overall gain.

    Temporal Resolution

    • Frame rate of the imaging system.
    • Higher frame rates provide better temporal resolution.

    Real-time Imaging

    • Displays movement as it happens.

    Doppler Ultrasound

    • Detects and measures blood flow.

    Doppler Effect

    • Change in apparent frequency of a wave due to relative motion between the source and observer.

    Axial Resolution

    • Ability to distinguish two structures along a path parallel to the sound beam.

    Biparietal Diameter (BPD)

    • Largest dimension of the fetal head measured perpendicular to the midsagittal plane, used to assess fetal development.

    Color Flow Doppler

    • Quantifies velocity direction by assigning a color to each pixel, with different colors representing different velocity frequency changes.

    Nuclear Medicine

    • Uses radioactive materials to test body functions.

    Administration

    • Radioactive substances, or tracers, are administered via injection, swallowing, or inhalation.

    Localization

    • Tracers concentrate in specific organs or tissues.

    Emission

    • Tracers emit gamma rays, which are then detected and form an image of the organ being studied.

    Atom

    • Fundamental building block of matter, the smallest part of an element containing all its properties.

    Nucleus

    • Positively charged central part of the atom containing most of its mass.
    • Made up of protons and neutrons.

    Electron Cloud

    • System of electrons moving around the nucleus at discrete energy levels.

    Chemical Bonding

    • Covalent bond: Formed by sharing electron pairs between atoms.

    Nuclear Transformation

    • Process by which a nucleus spontaneously emits particles to achieve stability, transforming into a different atom.

    Nuclear Medicine Physicist

    • Specialist with extensive education in basic and clinical sciences of medicine, licensed to work with radioactive materials.

    Nuclear Medicine Technologist

    • Educated in the theory and practice of nuclear medicine procedures, performing the tests.

    Physicist

    • Experienced in nuclear medicine technology and equipment, including computers.

    Collimator

    • Component of a gamma camera that filters out unwanted radiation, allowing only specific gamma rays to reach the crystal.
    • Types include converging, diverging, pinhole, fan beam.

    Photomultiplier Tube (PMT)

    • Converts light from the crystal into an electrical pulse.

    Converging Collimator

    • Holes converge to a focal point, providing magnification.

    Diverging Collimator

    • Holes angle opposite to converging collimators, creating a smaller image.

    Pinhole Collimator

    • Single 2-5 mm hole in the center, with image size dependent on source distance.

    Fan Beam Collimator

    • Combines parallel hole collimation along one axis and converging collimation along another.

    Sodium Iodide Crystal

    • Gamma rays interact with the crystal, releasing light photons.

    Pulse Height Analyzer

    • Analyzes the energy of the gamma rays, ensuring only those originating from the specific tracer are recorded.

    Scalar/Timer

    • Measures and records the number of gamma rays detected.

    Cathode Ray Tube (CRT)

    • Displays the image of the organ being studied based on detected gamma ray information.

    Ultrasound

    • Attenuation: Weakening of sound waves as they travel through a medium.
    • Absorption: Ultrasound energy lost to tissue energy, converted into heat.
    • Reflection: Sound energy strikes a boundary between two media, and some returns to the source. Most important characteristic of ultrasound.
    • Scattering: Interaction with smaller reflectors, causing reflection in multiple directions.
      • Rayleigh scattering: Occurs when the sound wave interacts with particles smaller than the wavelength.
    • Refraction: Occurs due to a difference in propagation speed between two media.
      • The beam is deviated as it travels through the medium, resulting in a bend in transmission and reflection.

    Acoustic Impedance

    • Represents the resistance of a tissue to the passage of ultrasound waves.
    • Calculated as the product of tissue density and the velocity of sound in the material.
    • A large difference in acoustic impedance between two media will cause a high percentage of the sound waves to be reflected back to the transducer.
    • High density substances: High acoustic impedance.
    • Low density substances: Low acoustic impedance.

    Piezoelectric Crystal

    • Composed of dipolar molecules that vibrate when electricity is applied.
    • The vibrations emit ultrasound pulses or mechanical waves.
    • Present inside the transducer.
    • Types:
      • Quartz (naturally occurring)
      • Lead zirconate tinate (man-made ceramic)

    Piezoelectric Effect

    • The ability of certain materials to convert mechanical energy into electrical energy and vice versa.
    • Direct piezoelectric effect: Production of an electric charge in response to applied pressure, resulting in an "echo".
    • Inverse piezoelectric effect: conversion of electrical energy into mechanical energy, resulting in a "pulse".

    Transducer/Probe

    • Converts electrical energy into ultrasound waves (mechanical) and vice versa.
    • Types:
      • Linear array transducer: Parallel scan lines, rectangular field of view, used in vascular, small parts, and musculoskeletal applications.
      • Sector/curvilinear array transducer: Provides a wide field of view, useful for abdominal and obstetric scanning.
      • Convex transducer: Wide fan-shaped, useful for all parts of the body except specialized echocardiography.
      • Phased array transducer: Flat-faced, wide field of view, used for cardiac and cranial ultrasound.

    Acoustic Lens

    • Reduces the beam width of the transducer to improve image resolution.
    • The width of the beam determines lateral resolution.
    • Lateral resolution: Ability to resolve structures across or perpendicular to the beam axis.

    Impedance Matching Layer

    • Sandwich between the piezoelectric crystal and the patient.
    • Chosen to improve the transmission of ultrasound waves into the body.

    Bandwidth

    • The range of frequencies contained within an ultrasound pulse.
      • Wide bandwidth:
        • Shorter spatial pulse length.
        • Wider range of frequency.
      • Narrow bandwidth:
        • Longer spatial pulse length.
        • Narrower range of frequency.

    Ultrasound Beam

    • Area through which the sound energy emitted from the ultrasound transducer travels.
    • 3D and symmetrical around its central axis.
    • Beam intensity: Measured in watts.
    • Near field: Area close to the transducer where the ultrasound beam is narrow and focused.
    • Far field: Area further away from the transducer where the beam diverges.

    Other terms:

    • Retrouterine pouch (cul-de-sac): Pelvic space located anterior to the rectum and posterior to the uterus; also known as the pouch of Douglas.
    • Sagittal: Plane that travels vertically from the top to the bottom of the body along the y axis.
    • Scattering: Diffusion or redirection of sound in several directions.
    • Sonar: (sound navigation and ranging) - Instrument used to discover objects underwater and to show their location.

    Nuclear Medicine

    • Branch of science that uses radioactive materials for diagnosis and treatment.
    • It determines and diagnoses based on organ or tissue function by utilizing radioactive tracers.
    • Radioactive tracer: Radioactive drug/material used in nuclear medicine procedures.
    • Radionuclide: Radioactive atom or nucleus with too many or too few nucleons.

    Radionuclide Decay

    • Beta plus decay (Positron decay): Proton-rich nucleus emits a positron (antimatter) and a neutrino.
      • One proton is converted to a neutron and a positron.
      • Decrease in atomic number by 1.
      • Isobaric transition.
    • Electron capture/K capture decay: Proton-rich nucleus captures an electron from the innermost electron shell (K-shell).
      • One proton is converted to a neutron.
      • Decrease in atomic number by 1.
      • Isobaric transition.
    • Beta minus decay: Neutron-rich nucleus emits an electron (beta particle) and an antineutrino.
      • One neutron is converted to a proton and an electron.
      • Increase in atomic number by 1.
      • Isobaric transition.
    • Alpha decay: Nucleus emits an alpha particle (two protons and two neutrons).
      • Atomic number decreases by 2, mass number decreases by 4.

    Therapeutic procedures

    • Treating diseases using radioactivity.
    • Radionuclide therapy is used in the treatment of:
      • Benign diseases: Hyperthyroidism, arthritis, and others.
      • Malignant diseases: Cancers.

    Radiopharmaceuticals

    • Substances containing radionuclides suitable for administration to humans for diagnosis or treatment of disease.
    • Gamma emitters: Used for image formation.
      • Do not emit alpha or beta particles.
    • Biologically active molecules:
      • Act as the tracer/carrier, determining the localization and biodistribution of the radiopharmaceutical in the body.
      • Influences the behavior and function of the radiopharmaceutical.

    Key Radiopharmaceuticals

    • Chromium (51Cr):
      • Half-life: 27.8 days.
      • Used for: Red blood cell volume and survival.
    • Cobalt (57Co):
      • Half-life: 270 days.
      • Used for: Vitamin B12 absorption.
    • Fluorine (18F):
      • Half-life: 110 minutes.
      • Used for: Oncology and myocardial hibernation.
    • Gallium (67Ga):
      • Half-life: 77 hours.
      • Used for: Inflammatory process and tumor imaging.
    • Indium (111In):
      • Half-life: 67.4 hours
      • Used for: Cerebrospinal fluid imaging.
    • Iodine (121I):
      • Half-life: 13.3 hours.
      • Used for: Thyroid function.
    • Iodine (131I):
      • Half-life: 8 days
      • Used for: Renal function.
    • Nitrogen (13N):
      • Half-life: 10 minutes.
      • Used for: Myocardial perfusion.
    • Rubidium (82Rb):
      • Half-life: 75 seconds
      • Used for: Cardiovascular imaging.
    • Technetium (99Tc):
      • Half-life: 6 hours.
      • Used for: Imaging of various organs, including brain, thyroid, liver, spleen, lungs, and heart.

    Imaging Applications

    • Single Photon Emission Computed Tomography (SPECT): Uses gamma camera to obtain 3D images.
    • Positron Emission Tomography (PET): Uses positron-emitting isotopes to produce high-resolution images of metabolic activity.

    PET Camera

    • Contains a ring of detectors (scintillators) surrounding the patient.
    • Detectors are coupled to PMTs to detect light produced in each detector.

    CT scan

    • Godfrey is considered the father of CT scan imaging.
    • In 1979, Hounsfield and Allan Mcleod Cormack shared the Nobel prize in physics for their work on CT imaging.
    • CT scan machines became widely available in 1980.

    EMI Scanner

    • The first CT scan machine.
    • Had 180 translations and 1 degree of rotation.
    • Acta was the first CT system that could make images of any part of the body.

    Conventional/Axial Tomography

    • The plane of the image is parallel to the long axis of the body.
    • Produces sagittal and coronal images.

    Computed Tomography

    • The plane of the image is perpendicular to the long axis of the body.

    CT Machine

    • Imaging time: 120 kvP, 400mA
    • High-speed rotors for heat dissipation
    • Anode head capacity: 7 MHU (Spiral CT)
    • Heat storage capacity: 8 MHU
    • Anode cooling rate: 1MHU/min
    • Small focal spot; ensures high spatial resolution imaging
    • Tube life: 5000 exposures (Conventional CT)

    Detector Array

    • The entire collection of detectors
    • Image receptor in CT
    • Detectors absorb radiation and convert it to an electrical signal.

    Detector Efficiency

    • The ability of a detector to capture transmitted photons and change them to an electronic signal.
    • High scatter suppression is important.
    • High stability allows a system to be operational without frequent calibration.

    Detector Types

    • Gas-filled detectors: previously used
    • Scintillation and SSD detectors: recently used

    Gas Detectors

    • Ionization of gas:
      • Ionization chamber
      • Proportional counter
      • Geiger-Muller counter
    • Characteristics:
      • Excellent stability
      • Large dynamic range
      • Low quantum efficiency

    Scintillation Detector

    • Photodiode: converts light into an electrical signal.
    • Does not require a power supply

    Three Important Factors Contributing to Detector Efficiency:

    • Geometric Efficiency:
      • The area of the detectors sensitive to radiation as a fraction of the total exposed area.
      • The amount of space occupied by the detector collimator plates relative to the surface area of the detector.
    • Quantum Efficiency:
      • The fraction of incident x-rays on the detector that are absorbed and contribute to the measured signal.
    • Conversion Efficiency:
      • The ability to accurately convert absorbed x-ray signal to an electrical signal.
    • Overall/Dose Efficiency:
      • The product of geometric, quantum, and conversion efficiency.
      • The product of:
        • Stopping power of the detector material
        • Scintillator efficiency (in solid-state types)
        • Charge collection efficiency (in xenon types)
        • Geometric efficiency
        • Scatter rejection
      • Normal value: between 0.45-0.85

    Nuclear Medicine

    • Branch of science that uses radioactive material for diagnosis and therapy
    • Determines and diagnoses based on organ or tissue function
    • Tracers: Radioactive drugs/materials used in procedures
    • Radionuclide: Radioactive atom or nucleus; too many or too few nucleons
    • Radiopharmaceutical: Traces a particular physiologic or pathology process

    Two Branches of Nuclear Medicine

    • Therapeutic procedures: Treat diseases by means of radioactivity
      • Used to treat:
        • Benign diseases (e.g. hyperthyroidism and arthritis)
        • Malignant diseases (e.g. cancer)
    • Diagnostic procedures:
      • Uses radioisotopes as tracers to detect certain physiological abnormalities

    Therapeutic Procedures

    • Treat diseases by means of radioactivity
    • Treatment of:
      • Benign diseases (e.g., hyperthyroidism and arthritis)
      • Malignant diseases (e.g., cancer)

    Diagnostic Procedures

    • Uses radioisotopes as tracers to detect certain physiological abnormalities

    Types of Diagnostic Procedures

    • Cell sequestration: Splenic imaging (heat damaged RBC), WBC
    • Receptor binding and storage: Adrenal medullary imaging, somatostatin
    • Phagocytosis: Reticuloendothelial system imaging
      • Antigen-antibody tumor imaging
    • Active transport: Hepatobiliary imaging, renal tubular function, thyroid and adrenal imaging

    Detection Process

    • Gamma camera or scintillation camera transforms emissions into images, providing physiologic or pathophysiologic information.

    Recording Process

    • The camera records information in a computer or film

    Geiger-Muller Counter

    • Voltage is increased even higher than in the proportional chamber application.
    • All the molecules of the gas are ionized, liberating a large number of electrons.
    • Results in a large electron pulse and detection of single events but not energy.
    • Used for contamination control in Nuclear Medicine laboratories.

    Types of Collimators

    • Parallel Hole Collimator:
      • Most common used collimator.
      • Consists of a large number of small holes, separated by the lead septa which are parallel to each other.
      • Usually perpendicular to the crystal.
      • Geometric efficiency is affected by:
        • Shape of collimator holes
        • Length of collimator holes
        • Diameter of collimator holes

    CT Scan

    • Godfrey Hounsfield - father of CT scan imaging
    • 1979 - Hounsfield and Allan Mcleod Cormack shared Nobel prize in physics
    • 1980 - CT scan machine became widely available

    EMI Scanner

    • First CT scan machine
    • 180 translation/1deg rotation
    • Acta - first CT system that could make images of any part of the body

    Conventional/Axial Tomography

    • Plane of the image is parallel to the long axis of the body
    • Produces sagittal and coronal images

    Computed Tomography

    • Plane of image is perpendicular to the long axis of the body
    • Uses a rotating x-ray tube and a series of detectors to create a 3D image

    CT Scanner Components

    • High Speed Rotors: for heat dissipation
    • Anode Head Capacity: 7 MHU (Spiral CT)
    • Heat Storage Capacity: 8 MHU
    • Anode Cooling Rates: 1MHU/min
    • Small Focal Spot: due to high spatial resolution imaging
    • Tube Life: 5000 exposures (Conventional CT)

    Detector Array

    • Entire collection of detectors
    • Image Receptor in CT
    • Detector: absorbs radiation and converts it to an electrical signal
    • High Detector Efficiency: ability of the detector capture transmitted photons and change them to an electronic signal.
    • High Scatter Suppression: reduces noise in the image
    • High Stability: allows the system to be used without interruption of frequent calibration

    Types of Detectors

    • Gas-filled detectors: previously used
      • Ionization chamber
      • Proportional counter
      • Geiger-Muller counter
    • Scintillation and SSD: recently used

    Gas Detector

    • Ionization of gas is the principle.
    • Three types:
      • Ionization chamber
      • Proportional counter
      • Geiger-Muller Counter
    • Characteristics:
      • Excellent stability
      • Large dynamic range
      • Low Quantum Efficiency

    Scintillation Detector

    • Depends on excitation
    • When ionization particles pass through certain crystals, it flashes light or scintillation is emitted.
    • Most commonly used type in nuclear medicine.
    • Used to measure the energy distribution of particles in addition to counting them.
    • High sensitivity to gamma rays. (PET Camera contains a ring of detectors surrounding the patient, detectors are coupled to PMT to detect light produced in each detector)

    Factors Contributing to Detector Efficiency

    • Geometric Efficiency: the area of the detectors sensitive to radiation as a fraction of the total exposed area
    • Quantum Efficiency: the fraction of incident x-rays on the detector that are absorbed and contribute to the measured signal
    • Conversion Efficiency: the ability to accurately convert absorbed x-ray signal to electrical signal
    • Overall/Dose Efficiency: the product of geometric, quantum and conversion efficiency. Product of the following factors:
    • Stopping power of the detector material
    • Scintillator efficiency (in solid state types)
    • Charge collection efficiency (in xenon types)
    • Geometric efficiency
    • Scatter rejection
    • Normal Value: between 0.45-0.85
    • Value: depends on the type of detector used.

    Photodiode

    • Converts light into an electrical signal
    • Does not require a power supply

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Ultrasound PDF

    Description

    Explore the fundamentals of nuclear medicine through this quiz, covering key concepts such as radioactivity, half-life, and modes of decay. Understand the processes like alpha decay and the significance of conservation laws in radioactive decay. Test your knowledge on how these principles apply to biological systems and medical applications.

    More Like This

    Nuclear Medicine and Radiology Quiz
    10 questions

    Nuclear Medicine and Radiology Quiz

    SustainableChrysoprase avatar
    SustainableChrysoprase
    MSC in Nuclear Medicine Entrance Exam Quiz
    6 questions

    MSC Nuclear Medicine Entrance Exam Quiz and Flashcards

    FasterNovaculite avatar
    FasterNovaculite
    Nuclear Medicine Quiz: Gamma and Beta Decay
    5 questions

    Nuclear Medicine Quiz: Gamma and Beta Decay

    ImmenseHyena avatar
    ImmenseHyena
    Radiotherapy
    27 questions

    Radiotherapy

    AppreciableDouglasFir avatar
    AppreciableDouglasFir
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser