Untitled Quiz

Medical Physics Introduction to Nuclear Medicine

• Course presented by Peyman Sheikhzadeh, PhD, from the Department of Nuclear Medicine and Medical Physics at Tehran University of Medical Sciences.

Medical Imaging Techniques

• Discovery of X-rays: Wilhelm Roentgen received the Nobel Prize in 1901 for his discovery.
• Radiopharmaceuticals: George de Hevesy received the Nobel Prize in 1943 for using isotopes as tracers to study chemical processes.
• Development of X-ray CT: Hounsfield & Cormack received the Nobel Prize in 1979 for developing X-ray computerized tomography.
• Development of MRI: Lauterbur & Mansfield received the Nobel Prize in 2003 for developing Magnetic Resonance Imaging.

Structural & Functional Imaging

• Nuclear Medicine is to physiology as Radiology is to anatomy.
• Images of both anatomical and function can be shown.

What Does Probe Mean in Imaging?

• Modality | Probe | Characteristic
• Radiology | X-ray | Electron Density
• Mammography | X-ray | Electron Density
• CT | X-ray | Electron Density
• Angiography | X-ray | Electron Density
• MRI | RF | Proton Density
• SPECT | Gamma Ray | Radionuclide Dis.
• PET | Gamma Ray | Radionuclide Dis.
• Sonography | Ultrasound | Acoustic Impedance

History

• Wilhelm Conrad Roentgen, a German physicist, discovered X-rays in 1901.
• X-rays were able to pass through his hand and image the bones and ring.
• He was awarded the first Nobel Prize for physics in 1901.

NM and PET Process

• Diagrams illustrating the processes.
• Chemical formulas are shown.

Radioisotopes and Radiopharmaceuticals

• Radioisotope: The radiation source (radioactive atom).
• Pharmaceutical: The vector molecule targeting the organ.
• Radiopharmaceutical (radiotracer): Radioisotope + pharmaceutical.
• Fluorine-18 + Glucose = 18F-FDG.

Why is Nuclear Medicine Different?

• Nuclear Medicine uses the organ as an emission source.
• Other modalities (e.g., X-ray, CT, MRI) use external sources.
• Nuclear Medicine complements other imaging modalities rather than replacing them.

NM Activity Poles

• Radiopharmacy (radiopharmaceuticals): Nuclear and biochemical industry.
• Functional Imaging: Clinical use (imaging) Physicians
• Instrumentation (camera, PET): Manufacturers/Physicist

A Review

• Nuclear decay rules: Based on conservation laws.
  • β⁻-decay: AX₂ → AYz+1 + e⁻ + ν
  • β⁺-decay: AX₂ → AYz⁻¹ + e⁺ + ν
  • e⁻-capture : AX₂ + e⁻ → AYz⁻¹ + ν
  • γ-decay and internal conversion: no changes for A&Z

Radioactivity

• A(t): disintegration rate at time t (decays/sec)
• N(t): number of nuclei at time t
• λ: decay constant (1/sec or 1/hr)
• λ = ln2/T₁₂ = 0.693/T₁₂
• Half-life: T₁₂ = ln2/λ = 0.693/λ
• SI unit: 1 Bq = 1 disintegration/second (Becquerel)
• 1 Ci = 3.7 x 10¹⁰ dps
• 1 mCi = 37 MBq
• NM imaging: ~ 1 to 30 mCi (30 – 1100 MBq)

Physical Half-life (T_p)

• T_p: Time required for the number of radioactive atoms to reduce by one half.
• N₁ = N₀e⁻^λt or A₁ = A₀e⁻^λt
• T_p = 0.693 / λ

Effective half-life

• T_e: Time to reduce radiopharmaceutical in the body.
• Te = Tp / (1 / Tp + 1 / Tb)
• if Tp >> Tb, Te ≈ Tb
• if Tp << Tb, Te ≈ Tp

Radionuclides used in nuclear medicine

• (Table showing radionuclides, decay modes, principal photon emissions, half-lives, and primary uses.)

Radiation Detectors in NM

• (List of radiation detectors used in NM, including survey meters, ionization chambers, Geiger-Müller detectors, dose calibrators, well counters, and thyroid probes.)

Ionization Chamber

• Signal strength is proportional to energy deposited.
• Used to measure radiation amount (exposure, air kerma).

Dose calibrator

• Measure activity only.
• Select isotope button.
• Drop sample to bottom.
• Quality control is regulated.
• Every patient dose is assayed before administration.

Dose calibrator quality control

• Constancy, tested daily.
• Linearity, tested quarterly.
• Accuracy, tested yearly
• Geometry, tested upon installation.
• Syringe and vial sizes.

Geiger-Müller Region

• Signal strength is independent of energy deposited.
• Used for measuring radiation presence.

Scintillation Detectors

• Two main components: scintillator and photomultiplier tube (PMT).
• Radiation energy deposition in scintillator causes light flashes.
• PMT detects and amplifies light signals.

Scintillation Detectors - Thyroid Probe (Nal(TI))

• Includes components.

Gamma Camera, Scintillation Camera

• Imaging technique.

How to obtain a NM image?

• Administer radiopharmaceutical (labeled pharmaceutical).
• Radiopharmaceutical concentrates in needed locations.
• Detect γ photons using γ camera (scintillation camera).

Step-by-Step PET Imaging Process

• Shows diagrams illustrating the imaging steps. (Explains the processes involved in each step.)

Basic Principle

• γ-rays are directed toward a Nal(TI) scintillator crystal.
• Multiple PMTs detect light flashes.
• Signal (proportional to energy) is converted to electrical pulses.
• Pulses are processed for energy discrimination and positioning.
• Image of radionuclide distribution is shown.

Nuclear Medicine is Emission Imaging

• γ photons are emitted from a patient.
• Energy is from 70 to 511 keV.
• Image quality is relatively poor due to limited photon number.

BUT: Nuclear Medicine is Molecular Imaging

• Radiopharmaceutical interacts with cells or molecules.
• Bound directly to target molecules (e.g., monoclonal antibodies).
• Accumulated by cellular/molecular activities.
• Molecular/cellular activities—e.g. perfusion, metabolism lead to earlier diagnoses.

Major Components of Gamma Camera

• Diagram showing components (crystal, PMT, pre-amp, amplifier, logic unit) and their functions.

Collimator

• Establishes relationship between γ photon source and detector.
• Has a major effect on count rate and spatial resolution.

Different Parallel-Hole Collimators

• Types of parallel-hole collimators; low-energy all-purpose (LEAP), low-energy high-resolution (LEHR), medium-energy all-purpose (MEAP), high-energy all-purpose (HEAP).

Collimators

• Types of collimators: parallel-hole, pin-hole, converging.

Scintillation Process in Detector

• Detector converts y photons to a number of blue photons.
• Number of blue photons proportional to energy deposited.
• Number of blue photons determines electron liberation, electrical pulse height and correlates to deposited energy.

Desirable Scintillator Properties

• High values of density and atomic number lead to high absorption efficiency, which then improves detector sensitivity.
• High light output improves conversion efficiency to improve energy discrimination, spatial resolution and linearity.
• Transparency to light emission further improves sensitivity.

Photomultiplier Tube (PMT)

• Creates and amplifies electrical pulses from light detection.
• Photocathode (e.g., CsSb) converts blue light to electrons.
• Dynodes amplify the electron signals.
• Anode collects the amplified electrons.
• Gain in electron number: ~ 10⁷

Photomultiplier Tube (PMT) - Additional Details

• PMT is directly coupled to crystal using a silicone compound.
• PMT takes light emissions from scintillation, converts to current pulses, then voltage pulses for amplification.
• Current pulse strength proportional to y photon energy.

Photomultiplier Tube (PMT) Continued

• 40-100 PMTs (5 cm in diameter) are common in modern gamma cameras.
• Photocathode coupled directly to the detector or via light guides.
• Anode connected to electronics in the tube base.
• Extremely sensitive to magnetic fields.

PMT Function

• Many PMTs arranged on crystal surface.
• Nearest tube receives strongest signal.
• System uses signals to determine photon origin.

Localization Electronics

• Processes pulses from the PMT into X, Y, Z pulses.
• Z pulse amplitude proportional to the energy in the crystal.
• X and Y pulse detection based on resistor network output.
• The position of the photon interaction is detected in space across the detector.

System Layout

• Block diagram showing components; gantry, gantry electronics, head (PMT, crystal, collimator), acquisition signal processor, table, computer processor, display monitor.

Image Formation (Photopeak)

• Diagram showing image formation, based on counted photons hitting the crystal.
• Example efficiency (0.02%) for a LEHR collimator is shown.

Scatter

• Major source of image degradation in NM due to scattering events.

Scatter in Patient

• Diagram showing scatter in patient.

Image Degradation - Septal Penetration

• Diagram illustrating septal penetration, a type of image degradation.

Image Degradation - Simultaneous Detections

• Diagram showing simultaneous detections, a potential source of image degradation and artifacts.

Image Degradation - Scatter

• Diagram showing scatter, a source of image degradation.

System Spatial Resolution

• Formula for system spatial resolution (Rs) based on intrinsic (R_int) and collimator (R_col) resolutions. Provides an example for ranges for the variables.

Collimator Resolution

• Diagram showing collimator (line spread function).
• Spatial resolution decreases with increasing distance between point source and collimator.

Data Acquisition

• Collimator criteria for matching the radioisotope energy window.
• Pixel size—1/3 or 1/2 the spatial resolution of the detector.
• Matrix size is determined by detector size/pixel size.
• Matrix size (64 x 64, 128 x 128, or 256 x 256) common for the detectors. Includes pixel depth in bytes.
• Scan count rate is considered important and should be <20,000/sec.

Effect of Matrix Size

• Diagram demonstrating differences in image quality with using 64 × 64 versus 128 × 128 matrix sizes.

Planar NM Imaging

• Diagrams of planar NM imaging systems.

Uniformity

• Example diagrams for showing different kinds of uniformity defects (e.g., collimator defect, bad PMT, shift in energy peak).

Bar Phantom

• Technique using lead stripes for measuring linearity and spatial resolution of the imaging system.

Tomographic NM Imaging (SPECT)

• Single photon emission computerized tomography technique.
• Diagrams of SPECT systems.

Tomographic Imaging (SPECT)

• Produces tomographic images by acquiring data at several angles around the patient.

SPECT

• 3-D images eliminate superposition of activity of slice
• Higher contrast and accuracy for lesion localization.

SPECT Data Acquisition

• Two detectors mounted at 180⁺ or 90⁺ on a rotation gantry.
• Sequence of 2-D static images at different positions.
• Range is 180⁺ with 2 perpendicular detectors or 360⁺ with 2 opposite detectors. A circular or elliptical orbit is better for images because of closer proximity to the patient.

SPECT Image Acquisition

• Typically uses 2 camera heads, rotating around the patient.
• Imaging takes ~15 minutes.
• Matrix size is 64 x 64 or 128 x 128.

Data Collection: Angular Stops

• 3 to 6 degrees per angular step.
• Number of stops/steps should be considered.

View number for 360º SPECT

• Number of views/projections are based on the matrix size.

Image with 128 x 128 matrix

• Contains 128 projections.
• Each projection has 128 data points.
• Equivalent to 128 slice CT (slices per rotation).

Sinogram (for one of many slices)

• Diagram showing sinogram (data storage space) concept, from a 1-D profile across data acquisition. Data is shown with angular positions.

Back Projection

• Leads to blurring because of streaks and star-like artifacts.

Filtered Back Projection

• Suppresses blurring using filtering of projections.
• Uses a high-pass filter (e.g., ramp filter) to accomplish the blurring reduction.

Filtered Back Projection (noiseless data)

• Diagram demonstrating filtered back projection; showing two, four and 256 angles.

Filter

• Available filters: ramp, and user-selected/characterized filter
• Shepp-Logan, Hahn, Buterworth, Weiner, and Hanning

Selection of Filters for SPECT

• Trade-off between noise and resolution for the filter choice.
• Considerations for patients and physician preferences and vendor recommendations.

Iterative Reconstruction (IR)

• Filtered Back Projection has some limits; corrections are often needed—e.g., attenuation and Compton scattering.
• Ordered Subsets Expectation Maximization (OSEM).

Iterative Reconstruction

• Slow comparison to filtered back projection.
• Commonly used in PET.
• Increasingly used for SPECT.

Image Reckon - Iterative

• Components involved in iterative reconstruction—data from camera, compare projections, update estimate, estimate, forward project.
• Number of iteration and subsets needed are shown.

Iterative Reconstruction Algorithms

• Diagrams showing iterative reconstruction, in iterations 1 - 30.

Brain Phantom

• Diagram showing reconstruction FBP (Filtered Back Projection) and IR (Iterative Reconstruction)

Non-filter Noise Factors

• Collimator, matrix (64 × 64 or 128 × 128).
• Slice thickness.
• Time per stop.
• Number of steps/stops.

Data Collection: Counts

• Activity in patient.
• Time per stop.
• Number of Steps.

Attenuation Correction

• Problem in radionuclide imaging due to attenuation.
• Correction can be important for judging lesion activity.

Uniform Phantom with Evenly Distributed 99mTc

• Diagrams with and without attenuation correction.

SPECT/CT

• Combined SPECT and CT scanners.

Patient Studies

• Advantages: no superposition, 3D lesion location, fusion with other imaging systems.
• Disadvantages: time consuming scan, images are noisy.

Introduction to the Physics of Positron Emission Tomography (PET)

• Introduction to PET.

Biograph Vision Quadra™

• PET system shown.

Gamma camera components

• Diagram showing stationary gantry, rotating gantry, detectors, and the patient table.

PET Scanner Components

• Diagram showing gantry, detector ring, and the acquisition/processing station

PET/CT Scanner

• Diagram showing gantry, PET detector and CT module.

PET/CT Power

• CT scan to show location of lesion
• PET/CT to measure activity of the lesion.

Anatomic and Functional Imaging

• Anatomic imaging uses modalities such as CT scans to determine location.
• Functional imaging uses methods such as NM to determine the activity of the region.
• Fusion of data from these two methods provides a clearer picture of patient condition.

Effective Dose of NM Procedures

• Table demonstrating an extensive range of different procedures for determining effective doses.

Dose Limits

• Table demonstrating recommended dose limits.

SPECT & PET

• SPECT, with 2 views from opposite sides,
• PET, acquisition is simultaneous.
• Spatial resolution is proportional to detector width (greatest in ring center) for SPECT ; spatial resolution for PET is not dependent on collimator size..

Advantages of PET over SPECT

• Superior spatial resolution.
• Higher sensitivity.
• Attenuation correction is possible.

Limitation of Functional Imaging

• Limited spatial resolution
• Poor signal-to-noise ratio.
• Poor uptake to the radiotracer. The image is registered to an anatomical image to improve the interpretation of image data.

Medical Imaging Techniques

• Diagram demonstrating anatomical, functional and hybrid imaging techniques.

Fusing Anatomy and Function

• Illustrates how anatomy and function can be combined: Hand-drawn, visually, software and hardware fusion methods.

History of Dual-Modality Imaging

• Timeline of important developments in SPECT/CT and PET/CT systems.

Gamma Camera Components

• Diagrams showing the concept of a gamma camera.

PET Scanner Components

• Diagram showing components of typical PET scanners.

PET/CT Scanner

• Diagrams showing components of typical PET/CT scanners.

The PET/CT Power..!

• Illustrates combining the data from CT and PET for identifying lesions in a patient.

Anatomic and Functional Imaging - Continued

• Diagram combining data from CT and NM modalities to gain further insight.

Effective Dose of NM Procedures - Continued

• Table demonstrating effective doses of different nuclear medicine procedures.

Attenuation Correction in PET/CT

• Diagrams showing attenuation correction of a patient image using a scout image/scan as a reference.

Photon Attenuation in PET

• Shows how photon uptake varies depending on the types of tissues (lungs, others, and skin).

Typical PET/CT Imaging

• Shows diagram for a typical PET/CT imaging flow chart for reconstruction and fusion processes.

Role of FDG

• FDG is not cancer-specific; it accumulates in areas with high levels of metabolism/glycolysis.
• Sites of possible higher FDG uptake: Hyperactivity(muscular/nervous), Active inflammation(infection, sarcoid, arthritis, etc), Tissue repair.

Hyperactivity

• Diagrams showing possible higher FDG uptake in pectoralis major muscle after strenuous exercise.

Inadequate Fasting

• Diagrams showing different levels of fasting effects when performing PET scans.

Semiquantitative PET: Standard Uptake Value (SUV)

• Calculation of SUV.
• SUV range as a cut-off for possible malignant vs. non-malignant pathologies.

SUV in Clinical Studies

• Numerator: highest pixel value for a region-of-interest (ROI) in SUV_max or SUV_mean calculations.
• Denominator: activity administered/body mass—usually lean body mass or body surface area—for background uptake.
• SUV interpretation factors: physiology and condition of the patient.
• Small changes in SUV must be thoroughly considered for accurate patient assessment.

Requirement for Reproducible SUV

• Scan conditions (e.g., uptake duration, scan length, scanning direction).
• Patient preparation (e.g., fasting, medication).
• Reconstruction parameters (e.g., slice thickness, filters).
• ROI definition.
• Consistency of the test is important to ensure accurate and reproducible results.

Clinical Use of PET

• Main clinical uses: oncology (90%) and cardiac/neuro (10%).
• Shown diagrams from some clinical use scans.

Typical Oncology Protocol

• Administered dose (10-20 mCi FDG).
• Uptake period (60 min) in quiet room for uptake and trapping, clearance from blood.
• Scanning (typically eyes-to-thighs, 6-7 positions, each position has a 15 cm FOV, 30 min total scan time).

Patient Dose (FDG)

• Effective dose to patient: ~7 mSv for 10 mCi (370 MBq) injection.
• Organ with most dose: bladder.
• Equivalent dose/dose from CT (AC) is ~5 mSv for 10 mCi (370 MBq) injection.
• CT (Diagnostic and Contrast) dosages are ~15-18 mSv.

SPECT & PET

• SPECT: acquisition uses 2 views from opposite directions.
• Resolution decreases with distance between collimator face and patient, ∝ detector width.
• SPECT sensitivity ~ 0.02%.
• PET: uses simultaneous acquisition method
• PET sensitivity is ~2-3%.
• PET uses electronic collimation.

Advantages of PET over SPECT

• Superior spatial resolution.
• Higher sensitivity.
• Possible attenuation correction.

Limitation of Functional Imaging

• Limited spatial resolution.
• Poor signal-to-noise ratio.
• Poor uptake in diseased tissues.

Medical Imaging Techniques

• Summarizes anatomical, functional, and hybrid imaging modalities and how they work.

Fusing Anatomy and Function: continued

• Description and comparison of hand-drawn, visual fusion methods, and hardware fusion for anatomy and function scans.

History of Dual-modality Imaging

• History of dual-modality imaging—SPECT/CT and PET/CT.

Gamma Camera Components

• Diagram illustrating the components for a gamma camera.

PET Scanner Components

• Diagram illustrating components for a PET scanner.

PET/CT Scanner

• Diagram illustrating the components for a PET/CT scanner.

Typical PET/CT Imaging

• Typical flow chart for PET/CT imaging showing the processes involved in data processing.

Role of FDG - Continued

• High FDG uptake is not specific to cancer.
• It can identify sites with high metabolism and/or glycolysis.

Hyperactivity

• Diagrams showing patients with FDG uptake in the pectoralis major muscle after strenuous exercise in the 24 hours prior to the scan.

Inadequate Fasting

• Diagrams showing images with inadequate fasting and Overnight fasting.

Semiquantitative PET: Standard Uptake Value (SUV) - Continued

• Definition of SUV calculation.
• SUV cut-off value of ~2.5 used as a determinant for diagnosis (malignant vs. non-malignant)

SUV in Clinical Studies - Continued

• Numerator for SUV calculation: highest pixel value from region of interest (ROI) scan.
• Denominator: activity administered per mass (Lean body mass, or body surface area)
• Factors affecting SUV values: physiologic status, uptake time, fasting, etc.
• Small changes in SUVs must be considered for accurate patient interpretation.

Requirement for Reproducible SUV

• FDG uptake period, scan length, and scanning range are needed.
• Patient preparation and/or medication need to be consistent to produce accurate SUVs.
• Reconstruction parameters (slice thickness, filters).
• Region of Interest (ROI) definition must be consistent for accurate result analysis.

Clinical Use of PET - Continued

• Oncology and Cardiac/Neuro applications are highlighted and diagrams are shown.

Typical Oncology Protocol

• Summary of the scan protocol for oncology.
• Dose, time-in-the room, scanning techniques, etc. are summarized.

Patient Dose (FDG)

• Summary of typical patient doses for both the FDG and CT scans.

SPECT & PET - Continued

• Summary of SPECT and PET properties and methods/processes; the characteristics of both imaging methods are compared.
• Resolution is shown to correlate with the characteristics of both modalities.

Advantages of PET over SPECT - Continued

• Advantages of PET over SPECT are summarized.

Limitations of Functional Imaging

• Summarizes limitations of imaging, including limited spatial resolution, poor signal-to-noise ratio, and poor uptake by the radiotracer.

Medical Imaging Techniques

• Summary of the anatomical, functional, and hybrid imaging techniques.

Fusing Anatomy and Function - Continued

• Summary of methods for fusing anatomical and functional techniques are shown, including hand-drawn, computer-based, and hardware-based.

History of Dual-Modality Imaging

• History of SPECT/CT and PET/CT systems is shown for each modality.

Gamma Camera Components

• Diagrams summarizing the components within the gamma camera system.

PET Scanner Components

• Diagram summarizing the components within the PET scanner.

PET/CT Scanner

• Diagram summarizing the components within the PET/CT scanner.

The PET/CT Power!

• Shows what the combined PET and CT imaging provides.

Time of Flight PET

• How time of flight is used to improve PET imaging efficiency and image resolution.
• Data is shown demonstrating better resolution with Time of Flight methods and processes when compared to without.

Attenuation Correction

• Shows attenuation correction using scout images/scans as reference.

Photon Attenuation in PET

• Shows difference in scan data interpretation with/without attenuation based on tissue types (lungs, others, and skin).

Typical PET/CT Imaging

• Diagram illustrating flow chart of PET and CT processes.

Role of FDG

• Shows the Role of FDG—high uptake is not specific to cancer.
• High FDG uptake in tissues with high metabolism/glycolysis.

Hyperactivity

• Shows diagrams with higher FDG uptake and hyperactivity effects.

Inadequate Fasting

• Shows diagrams with different levels of fasting effects when performing PET scans.

Semiquantitative PET: Standard Uptake Value (SUV) and Clinical Studies

• Definition of SUV calculation.
• SUV cut-off value of ~2.5 used as a determinant for diagnosis.

SUV clinical studies

• Method.

Requirement for Reproducible SUV

• Consistent conditions regarding the FDG uptake period, patient preparations & medications, and reconstruction parameters and/or ROI sizes.

Clinical Use of PET

• PET oncology and cardiac/neuro applications

Typical oncology protocol

• Protocol summary for oncology scans—e.g., dose, time, acquisition, positions, and total scan times.

Patient dose (FDG)

• Effective dose to patient in mSv is shown.
• Dose for CT scans (for AC) is shown.

SPECT & PET - Continued

• Summarizing SPECT and PET properties, techniques, acquisition, and processes; and comparing the characteristics of both imaging methods to provide an image resolution comparison
• Resolution correlated with characteristics of both modalities.

Advantages of PET over SPECT- Continued

• Summary of PET advantages over SPECT are shown.

Limitations of Functional Imaging

• Limitations of the imaging modality are summarized.

Anatomical and functional Imaging

• Summary of Anatomical and Functional Imaging methods.

Fusing Anatomy and Function

• Summary of methods for combining anatomical and functional techniques (e.g., hand-drawn, visual, Software and Hardware).

History of Dual-Modality Imaging - Continued

• History of SPECT/CT and PET/CT is summarized based on the different imaging methods.

Detector Materials

• Summarizing the main detector materials used in PET, e.g., BGO, LSO, GSO, and LYSO. Gives the material provider.

Advantages of PET Imaging

• Diagram illustrating advantages of PET imaging over SPECT imaging.

Detector Blocks PET

• Summarizes the components for PET scanner, the dimensions, and the method of acquiring the data.

Advantages of PET Imaging continued

• Summary of advantages of PET imaging.

2014 PET image of the ACR phantom

• Diagram showing image and resolution.

2014 SPECT image of the ACR phantom

• Diagram showing image and resolution.

Time-of-Flight PET

• Use of TOF and effect on scan rate, and image noise/resolution. Example measurements provided

Time of Flight PET image of a big patient

• Diagram illustrating improved image quality with use of TOF analysis.

Discovery PET/CT 710 (GE), Ingenuity TF PET/CT (Phillips), Biograph TruePoint PET/CT (Siemens)

• Diagrams illustrating various PET/CT systems.

Attenuation Correction in PET/CT

• Explains the concept of using CT data to correct for attenuation in PET scan images.

Photon Attenuation in PET - Continued

• Shows how photon uptake varies depending on the types of tissues (e.g., lungs, others, and skin).

Typical PET/CT Imaging-Continued

• Shows a typical PET/CT imaging flow chart indicating the steps to image fusion and reconstruction

Role of FDG Continued

• High FDG uptake is not cancer-specific—High uptake in tissues with high metabolism/glycolysis.

Clinical Use of PET- Continued

• Clinical applications of PET scan and uses of different radiotracers.

Typical Oncology Protocol - Continued

• Clinical protocol summary for oncology scans.

Patient Dose (FDG)- Continued

• Detailed summary of typical patient doses for FDG and CT scans.

SPECT & PET - Continued

• Comparison of resolution & sensitivity of SPECT vs. PET.

Advantages of PET over SPECT

• Diagram summarizing advantages of PET over SPECT.

Limitations of Functional Imaging - Continued

• Limitations of functional imaging are summarized.

Anatomical and functional Imaging

• Summary of the anatomical and functional imaging modalities and methods or processes.

Detector Materials

• Main detector materials used in PET (e.g., BGO, LSO, GSO, and LYSO) are summarized in a table.

Advantages of PET Imaging - Continued

• Summary of advantages of PET imaging.

Detector Blocks PET

• Details of detector block elements for PET scanners.

Advantages of PET Imaging - Continued

• Summary of advantages of PET imaging.

2014 PET image of the ACR phantom - Continued

• Diagram of image and sphere diameter. Displays of the results.

2014 SPECT image of the ACR phantom - Continued

• Diagram of image and sphere diameter.

Time-of-Flight PET - Continued

• Use of TOF to improve scan time/image quality.

Attenuation Correction

• Shows attenuation correction, including a scout image to be used in calculation.

Photon Attenuation in PET - Continued

• Shows how photon uptake varies, and the image interpretation difference with/without attenuation compensation, based on tissue type (lung, other, skin).

Typical PET/CT Imaging - Continued

• Typical flow chart showing PET and CT processes.

Role of FDG - Continued

• High FDG uptake is not specific to cancers, but will have high uptake in tissues with high metabolic rate/glycolysis.

Clinical Use of PET - Continued

• Clinical applications of the PET scan and/or use of various radiotracers, presented in a table.

Typical Oncology Protocol - Continued

• Summary of the scan protocol for oncology, including dose, time, locations for scanning and total scan times.

Patient dose (FDG)- Continued

• Typical patient doses (FDG and CT, in mSv).

SPECT & PET continued

• Comparison of SPECT and PET properties and methods/processes, and comparing the characteristics of both imaging methods.
• Diagram illustrating the characteristics of each modality.

Advantages of PET over SPECT

• Additional advantages of PET over SPECT are provided.

Limitations of Functional Imaging Continued

• Limitations of the functional imaging methods, including resolution, signal-noise ratio, and uptake of radiotracer in diseased tissues