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Introduction to PET/CT MD
Chapter 1: The Science & The Scan

Chapter 1: The science and the scan

"Boring, But Necessary"

1. What is a PET/CT Scan?

  • Hybrid Imaging System
  • Anatomic & Functional Exam
  • The Machine
  • “Whole Body” vs. “Skull Base to Mid-Thigh”
  • Three Sets of Images
    Produced

2. Basic Science 18F-FDG

  • Glucose Analog
  • Malignancy & Glucose Metabolism
  • Mechanisms for Increased Intracellular Glucose
  • Why 18F-FDG Works

3. Power of PET/CT

  • Whole Body Assessment
  • The “You’re Kidding Me!” Effect
  • Post-Therapeutic Scar vs. Active Malignancy

4. Indications for PET/CT

  • Detecting Malignancy
  • Staging Malignancy
  • Assess Response to Therapy
  • Detecting Recurrence

5. The Limitations of PET/CT

  • Not All Cancer is FDG-Avid
  • Normal FDG-Uptake vs. Pathologic Uptake
  • Technical Limitations
    • Poor Patient Preparation
    • Misregistration
    • Brown Fat Activation
    • SUV Problems
    • Fields of View Discrepancy
    • PET/CT Artifacts
    • Timing of Exam After Therapy

6. Images Generated

  • CT Images
  • Non-Attenuation Corrected Images
  • Attenuation Corrected Images
  • Maximum Intensity Projection (MIP)
  • Fusion of Images
  • All Images Viewed in 3 Planes

7. Contrast Media: Oral & I.V.

  • Who Gets Oral Contrast?
  • Who Gets IV Contrast?
  • Oral Contrast “Cocktail” Recipe

8. What the Patient Should Expect

  • Documenting Height & Weight
  • Private Resting Room
  • Drinking PO Contrast
  • FDG Injection
  • Delay Between Injection & Scan

9. Safety Concerns with PET/CT Imaging

  • Radiation Exposure to Patient
  • Radiation Exposure to Patient’s Contacts
  • Patient Contact with Pregnant Women
  • Breastfeeding
Chapter 2: PET/CT Problems Which Limit Interpretation

Chapter 2: PET/CT Problems Which Limit Interpretation

"Something just doesn't seem right here"

1. Poor Patient Preparation

  • Optimizing Glucose & Insulin Levels
    • Fasting Prior to Exam
    • Diabetic Patients
    • Low Carbohydrate Diet
    • Hydration
  • Strenuous Exercise
  • Voiding Prior to Exam
  • Patient Instruction Sheet

2. Brown Fat

  • Definition
  • Distribution / Appearance
  • Don’t Miss the Hidden Nod
  • Reporting Language
  • Prevention

3. Timing of PET/CT Exam After Therapy

  • “Rule of 3”
    • Chemotherapy: 1 month
    • Surgery: 2 months
    • Radiation: 3 months

4. Misregistration

5. Extravasation of FDG

  • False Positives
  • False Negatives
  • Reporting Language

6. PET/CT Artifacts

  • Beam Hardening
  • Diaphragmatic Mismatch
  • Linear Hand Motion
  • Attenuation Correction
  • Differing Fields of View

7. The “Sponge Effect”

  • Poor Patient Preparation
  • FDG Extravasation
  • Extensive Brown Fat
  • Metformin-Induced Bowel Uptake
  • Marked Reactive Marrow Uptake
  • Extensive Tumor Uptake in

8. SUV Complications

  • Different Types of SUV Measurements
  • Factors that Influence SUV Measurements
  • What SUV Number Indicates Malignancy?
  • What Percent Change in SUV on a Follow Up Exam is Significant?
  • How to Compare Exams With Very Different Background Metabolic Activities?
Chapter 3: The Standardized Uptake Value (SUV)

Chapter 3: The Standardized Uptake Value (SUV)

"The good, the bad & the ugly"

1. What is the SUV & Why Used?

  • Quantitative vs. Qualitative Assessment
  • Unitless Measurement
  • Formula
  • SUV = ?

2. Variables that Affect SUV

  • Patient Preparation
  • Time Between FDG Injection & Scan
  • Partial Volume Effects
  • Extravasation
  • Patient Weight
  • Size & Position of ROI
  • Attenuation Correction Artifacts

3. Types of SUV Calculations

  • Consensus?
  • Body Weight
  • Lean Body Mass
  • Ideal Body Weight
  • Body Surface Area
  • Maximum vs. Mean
  • Average SUV’s by Organ

4. Interpreting the SUV: Threshold Values, “Oncologic Plausibility” & Relative Uptake

  • Precise Threshold Values?
  • “Oncologic Plausibility”
  • Relative Uptake
  • Assessing Nodes in Lymphoma Cases
  • Assessing Nodes in Non-Lymphoma Cases
  • Potential Lesions in Solid Organs
  • Pulmonary Nodules

5. What % Change in SUV on a Follow Up Exam is Clinically Significant?

  • The Problem
  • Current Recommendations

6. How to Compare Sequential Exams With Very Different Background Activities?

  • Differing Background Metabolic Activities
  • When Qualitative Assessment is Required
  • Reporting Language

7. Should We Just Abandon the SUV?

  • Pros & Cons
  • “Qualitative” Definitions
    • Mild
    • Moderate
    • Intense
  • Final Recommendations
Chapter 4: Our Systematic Approach to Reading a PET/CT

Chapter 4: Our Systematic Approach to Reading a PET/CT

"Eat your vegetables"

1. Reading Station & Reading Software

  • Reading Station
  • Monitor Set-Up
  • PET/CT Reading Software
  • Hanging Protocol

2. General Reading Caveats

  • Reading in Context (“Oncologic Plausibility”)
  • Measure Size on CT, Not on PET Images
  • Abnormality Seen Only on First PET Image
  • Assess the Patient’s Main Pathology Last
  • Beware the Ureter

3. Excellent Views: The MIP, Coronal & Sagittal Images

  • 3-D Rotating MIP & Coronal “Quick MIP”
  • Coronal PET
  • Sagittal PET

4. Written Annotations While Reading

  • Numbers, Numbers & More Numbers
  • Size & SUV Annotation System
  • Sample Annotation Sheet

5. The Language of Reporting

  • Goals of Reporting
  • Lawyers, Lawyers & Lawyers
  • Sample PET/CT Report
    • Negative Exam
    • Positive Exam
  • Patient Questionnaire
  • Technologist’s Data Sheet

6. The Read

  • Huge Exam: Requires Systematic Approach
  • Our “12-Step Reading System”
  • “The Read” in Action: Sample Case (Video)
  • Annotations for Sample Case
  • Final Report for Sample Case
Chapter 5: Normal Physiologic Distribution of FDG

Chapter 5: Normal Physiologic Distribution of FDG

"The essentials"

1. Introduction

  • To Locate Cancer, First Eliminate:
    • Normal FDG-Avid “Structures”
    • Benign FDG-Avid “Findings”

2. Head & Neck

3. Chest

4. Abdomen

5. Pelvis

6. Miscellaneous

Chapter 6: Benign FDG-Avid “Findings” & Common Diagnostic Challenges

Chapter 6: Benign FDG-Avid "Findings" & Common Diagnostic Challenges

"Separating the Expert from the Not-So-Expert"

1. Introduction

2. Head & Neck

3. Chest

4. Abdomen & Pelvis

5. Miscellaneous

5. Miscellaneous (continued)

Chapter 7: The Bones

Chapter 7: The Bones

"...is connected to the..."

Chapter 8: The Cancers

Chapter 8: The Cancers

"Putting it all together"

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