PET/CT in Oncology

PET/CT in Oncology

Overview of Imaging Technologies

• CT: Computed Tomogram

  • Evolution of Technology:

  • 1973: Introduction of CT technology

  • 2000: Progression in imaging

  • 2001: Development of PET/CT technology

• PET: Positron Emission Tomography

Imaging Protocols

• CT Imaging:

  • Topogram (scout): Used as a preliminary scanning method

  • CT Scan Duration: 1 minute

• PET Imaging:

  • Brain Scan Duration: 10 minutes

  • Heart Scan Duration: 10 minutes

  • Body Scan Duration: 20 minutes

• Patient Preparation:

  • Fasting required: 4 hours prior to the exam

  • Inject tracer before the scan

  • Begin scanning 60 minutes post-injection

PET Tracer Information

• Tracer Used: 18F-fluorodeoxyglucose (FDG)

  • Mechanism: Taken up by cells in proportion to their metabolic rates

  • Components: FDG Glucose, FDG Glucose-6-P, Plasma, Cell

Technical Specifications for Imaging

• CT Specifications:

  • KVs: 130 kV

  • mAs: 75 mA

  • Slice Thickness: 5 mm

• PET Specifications:

  • Tracer Dose: 15 mCi

  • Scanning Time for FDG: 1 minute

Advantages of PET/CT

• Advantages of CT:

  • High spatial resolution

• Advantages of PET:

  • Enhanced lesion detection

  • Better characterization of lesions

Applications of PET/CT

• General Application Statistics:

  • 76% of exams applied in Body imaging

  • 90% of exams applied in Brain imaging

  • 5% of exams applied in Heart imaging

• Specific Applications Include:

  • Epilepsy diagnosis

  • Tumor assessment

  • Dementia evaluation

  • Perfusion analysis

  • Viability examination

  • Infection detection

  • Bone imaging

  • An estimated 1.5 million PET/CT exams performed annually

Clinical Applications in Tumor Imaging

• Primary Uses:

  • Detecting radiographically occult lesions

  • Characterizing radiographic abnormalities

  • Evaluating extent of disease

  • Evaluating response to therapy

Normal vs. Abnormal PET/CT Scans

• Normal PET/CT scan: Details are depicted visually in slides (requires QuickTime)

• Abnormal PET/CT scan: Differences from normal aspects are highlighted visually in slides

Diagnosis, Staging, and Restaging with PET/CT

• Use Cases Include:

  • Various cancers: Head & Neck, Thyroid, Breast, Lung, Esophagus, Colon & Rectum, Cervix, Lymphoma, Melanoma

  • Medicare Approved Indications for PET/CT:

  • Follicular lymphomas with specific markers

  • Non-small cell lung cancer under specific conditions

National Oncologic PET Registry

• Website: http://www.cancerpetregistry.org

• Overview:

  • Sponsored by AMI, Managed by ACR for CMS

  • As of April 15, 2008, 1,728 facilities and 74,541 scans since May 2006

• Data Collection Forms:

  • Pre PET/CT Form includes:

  • Indication for PET/CT

  • Cancer type and extent

  • Management plan

  • Post PET/CT Form includes:

  • Change in assessment of disease extent

  • Change in management plan

National Comprehensive Cancer Network (NCCN)

• Linked Cancer Research Centers in USA Includes:

  • Fred Hutchinson Cancer Research Center

  • Huntsman Cancer Institute

  • Robert H. Lurie Comprehensive Cancer Center

  • Others across various states and regions

Specific Cancer Types Related to PET/CT

• Major cancers indicated for PET/CT include:

  • Acute Myeloid Leukemia

  • Breast Cancer

  • Bladder Cancer

  • Bone Cancer

  • Colorectal Cancer

  • Non-Hodgkin's Lymphoma

  • Non-Small Cell Lung Cancer

  • Others specific to systemic guidelines

Lesion Characterization Cases

• Clinical Case Examples:

  • 47-year-old man with a pulmonary nodule discovered incidentally

  • 84-year-old man with a 13 mm nodule revealed via chest X-Ray (CXR)

  • 73-year-old woman with rising CEA levels after colon cancer resection and negative CT results

  • 70-year-old male with Head & Neck cancer details provided

  • 47-year-old man with recurrent thyroid cancer documented through FDG PET

Monitoring Response to Treatment

• Illustrated cases include:

  • Variations in patient conditions post-treatment, such as stage 3A lung cancer cases with chemotherapy indications

Comparing Imaging Techniques

• Comparison of CT and PET/CT:

  • Standard Methodology: CT followed by PET/CT in certain complicated cases

  • Notations about Resolution: Low resolution of the CT component can be noted in certain instances

Problems and Pitfalls in Imaging

• Common Issues:

  • False Positive Findings: Can occur due to normal physiology, granulomas, certain infections, adenomas, and tumor characteristics

  • Lesions less than 8 mm may led to false-negative results, especially in diabetic patients or non-fasting scenarios

Key Examples of Clinical Scenarios in Imaging

• Physiological uptake noted in brown fat

• Infection case of a 68-year-old man with a solitary lung nodule confirmed as aspergillosis

• Granulomatous disease case description leading to a biopsy result of sarcoidosis

• Various adenoma cases with relevant imaging specifics and demographics presented

Clinical Impact of PET/CT

• Advantages highlighted:

  • Increased accuracy in diagnosis

  • Reduction in unnecessary testing and harmful procedures

  • Enhanced management and treatment pathways

National Oncologic PET Registry Findings

• Top Ten Cancer Sites Noted:

  • Ovary & Uterine Adenexa, Prostate, Pancreas, Kidney

  • Notable change in treatment decisions based on PET/CT findings (up to 36.5%)

Conclusions drawn from PET/CT Data

1. Primary Recommendation: CT is usually the first imaging test recommended.

2. PET/CT's Superiority: More accurate than using CT alone, particularly in characterizing difficult-to-biopsy lesions, detecting occult cancers, and assessing cancer extent and treatment response.

3. Impact on Management: Noted 36% change in patient management decisions based on PET/CT outcomes.

Quoted Anecdote Regarding Imaging Procedures

• Humorous Context: Cited scenario relating to exploratory surgery revealing negative results, emphasizing real-world empathy and experience in medical protocol.