1. PET/CT: Improved Confidence in Imaging?
PET/CT: Improved Confidence in Imaging

2. Why PET/CT Improved diagnostic accuracy over PET or CT alone
More Accurate Disease Staging
More Accurate Surgical Planning
More Accurate Guided Biopsy
More Accurate Radiation Therapy Planning
IMPROVED DIAGNOSTIC CONFIDENCE
(for improved patient management)

3. History of Radiology and Cancer
“50 Years of Imaging Form”
Form = Anatomy
Anatomy continues to be the cornerstone of cancer imaging for diagnosis, staging and follow up.
Form has served us very well in X-Ray, US, CT, and MR MR CT

4. “Form” Strengths and Limitations
Strengths …but Diagnostic Questions Remain
Clear delineation of form What is normal? Performance is
less post operative due to distortion
of normal anatomy
Accurate detection and What is the mass? (fat? water? air?)
localization of masses
Accurate detection of lymph What is within the lymph nodes?
nodes (present or absent) (benign or malignant?)
Some small lesion What is the cause?
identification
Have small tumor foci been over- looked (especially if surrounded by
normal tissues)?

5. “Form” Strengths and Limitations
Treatment Planning Questions Also Remain
What will be the response to a particular therapy?
What sort of tumor biology is present?
Has there been a response (especially cytostatic) that I’m not seeing yet because it’s too soon for the “form” to reflect changes?
PET (and PET/CT) address many of the limitations
of anatomic imaging alone

6. “Function” Imaging – FDG-PET
FDG-PET Strengths …but
High sensitivity for detection of abnormal cell metabolism
Real-time measurements of changes in disease state (and hence effectiveness of therapy)
Powerful rotating display formats to aid in accurate interpretations based on human motion-oriented vision

7. “Function” Imaging – FDG-PET
…but Questions Remain
Where is the tracer uptake?
Where should we biopsy?
Where should we resect?
Is the tracer uptake in tumor or non-malignant tissues (e.g. infection)?

8. Tough Questions CT shows infiltrates at both lung bases.
Clearly abnormal.
PET shows modest basilar lung FDG uptake?
What is it?

9. What is PET/CT? Where Form meets Function
A view into the body that allows us to see what it is happening and where.
Hybrid Imaging Device/Modality
Diagnostic CT scanner (high quality images of anatomy)
PET scanner (high quality images of function)
Computer and software to fuse/display images
No patient motion between studies (or very little)

10. Where Form meets Function
What is PET/CT?
normal heart
Where Form meets Function
The best of detection
and localization
Better than
PET or CT alone
lung cancer

11. More Accurate Staging PET/CT
Sensitivity to hyper-metabolism in normal-sized nodes on CT.
Accurate spatial localization of abnormalities detected on PET, but difficult to localize.

12. More Accurate Staging
NSCLC
5mm lymph node met
No enlarged lymph nodes seen in the apex of the thorax on CT.
Focal area of increased radionuclide uptake found on PET. Exact location remained unclear.
PET/CT fused image matched hyper- metabolism to a normal-sized lymph node.
Metastatic disease confirmed via histology.
Chemotherapy initiated.
Lardinois, et. al.,
NEJM 2003, 348:

13. More Accurate Staging Breast cancer patient
Malignant cell activity localized in a normal sized axillary lymph node.
Disease overlooked on CT alone.
Hao Vuong, MD,
Baptist Hospital of Miami

14. More Accurate Surgical Planning
Colorectal cancer patient
PET/CT demonstrates a solitary met in the liver
Upstages patient to Stage IV
Hao Vuong, MD, Baptist Hospital of Miami
Despite Stage IV, PET/CT indicates there is still a possibility of surgical cure, based on the localization of primary and metastatic activity.

15. More Accurate Guided Biopsy
CT shows LUL mass consistent with Lung Cancer and no nodal metastases
PET shows right paratracheal uptake suggesting nodal metastasis
PET/CT shows metastasis to normal sized right paratracheal node
Proven by biopsy.

16. More Accurate Guided Biopsy
Head and Neck cancer patient
PET/CT identifies a nasopharyngeal squamous cell carcinoma
Confirms increased metabolic activity is localized in a bilateral lymph node.
Patient therapy plan is changed from limited-field radiation treatment to a combined radiation/chemotherapeutic approach.

17. More Accurate RT Planning
PET/CT is performed on a radiation therapy table to ensure consistent patient positioning.
Fiducial markers are evident in the images.
PET/CT images can be moved directly into radiation therapy planning workstations for seamless integreation of metabolic, anatomic, and irradiation planning information.

18. More Accurate RT Planning
History
63 YOF, nasopharyngeal cancer 5 yrs prior
Presents with progressive dysphagia and neck pain
Panendoscopy negative, MRI unrevealing
PET/CT Findings
FDG accumulation in the posterior aspect of the larynx (SUV= 15.8) – not shown here
Small focus with mild FDG uptake (SUV = 1.2) corresponding to a small lymph node in the left neck.
Impact to Patient Management
Deep biopsies confirmed squamous cell carcinoma, likely the development of a second primary head and neck cancer.
Mild FDG uptake in the small node is likely to be metastatic.
Radiation therapy was selected as the primary treatment. The PET/CT images were used in planning the radiation therapy.
SUV = 1.2

19. Improved Confidence CT is clearly abnormal PET is mildly abnormal
Bronchioloalveolar Carcinoma
CT is clearly abnormal
PET is mildly abnormal
When combined: Worrisome for brochioloalveolar carcinoma
Confirmed by biopsy

20. Characterization and Localization
CT shows precise lesion size, shape and location
PET shows increased FDG uptake
Non-Small-Cell Lung Cancer

21. Confirmation of Benign Nodule
CT shows pulmonary nodule which is large enough to image with PET
PET shows no increased tracer uptake
No disease present

22. Better than PET or CT alone
Diagnostic Accuracy with Respect to Tumor Stage (40 Pts)
Non-Small-Cell Lung Cancer
Classification
Correct but
Imaging Method Correct Equivocal Incorrect
CT alone 58% 20% 22%
PET alone 40% 40% 20%
Visual correlation of 65% 12% 22%
PET and CT
Integrated PET-CT 88% 10% 2%
Lardinois, et. al., NEJM 2003, 348:

23. Better than PET or CT alone
Diagnostic Accuracy with Respect to Node Stage (37 Pts)
Non-Small-Cell Lung Cancer
Classification
Correct but
Imaging Method Correct Equivocal Incorrect
CT alone 59% 5% 35%
PET alone 49% 38% 14%
Visual correlation of 59% 11% 30%
PET and CT
Integrated PET-CT 81% 3% 16%
Lardinois, et. al., NEJM 2003, 348:

24. Improved Certainty
History of Melanoma
What is Tumor?
What is Not?

25. Normal Tissues with FDG Uptake
Not everything using glucose is tumor.
Anatomy can be helpful in making this separation.
Example:
Normal Head and Neck areas of increased FDG metabolism
(Minimize by NOT talking during uptake nor swallowing)
Tonsils
Submandibular and Parotid Glands
Cricoarytenoid muscles

26. Normal FDG-PET Map Parotids, Soft Palate, Spinal Cord
Transaxial images of parotid glands (A, arrows), soft palate (A, arrowhead), spinal cord (A, small arrow),
Parotids, Soft Palate, Spinal Cord

27. PET/CT: Faster Scan Time
Much faster total scan time than PET alone (approx 20 minutes)
CT provides 30 second transmission scans for the PET study vs 20 minute transmission scans with PET only devices
40-50% increased scan volume capacity
Improved cost-effectiveness with improved productivity
20 min emission
20 min transmission
20 sec transmission
PET Only
PET/CT
40 min
20 min

28. Patient preparation Fasting for four hours
Patient changed into gown and pants
All metallic objects are removed
Check glucose levels
< 200 mg/dl
2 bottles of Readi-CAT (Barium sulphate 1.3 %) oral CT contrast prior to injection of 18F-FDG
We switched to using oral contrast as of November of last year. Add barium concenrtration.

29. Patient Preparation PET Scan Preparation Fasting for 4 hours
Patient changed into gown and pants
All metallic objects are removed
Check glucose levels (< 200 mg/dl)
.22 mCi/kg FDG for whole body imaging (injected dose varies by scanner)
2D or 3D imaging of whole body (3D imaging of brain)
CT Scan Preparation
Patient is positioned head first and supine on the table
Scanning begins from meatus of ear to mid thigh
Shallow breathing during the CT
Currently, non contrast CT is best choice for transmission images as arterial contrast can cause artifacts

30. Scan Protocols PET Scan Protocol
3-5 minute emission per FOV for Whole Body imaging
3 minute emission per FOV for Melanoma imaging (more FOVs)
10-20 minute emission for 3D brain imaging
CT Scan Protocol
Helical
High Speed
Pitch 6
22.5 mm/rotation
5 mm slices
140 kV & 80mA—varies
50 cm DFOV
512 x 512 matrix

31. PET/CT (Fusion) Workstations
Fusion occurs on the PET/CT scanner workstation
Hi-Res CT images are minimized to 128x128 matrix
Images can be displayed in any plane or slice
MIP (3D PET images) and CT Scout views are provided
Entegra images here

32. Where Form meets Function
PET is Very Accurate.
PET/CT is even more Accurate.
Disease Staging
Surgical Planning
Guided Biopsy
Radiation Therapy Planning
PET/CT
Better than PET or CT alone
Editor: Richard L. Wahl, M.D.
Division of Nuclear Medicine
Department of Radiology
Johns Hopkins Medical Institutes
Other Contributors:
Hao Vuong
Baptist Hospital of Miami
Jack Ziffer
Homer Macapinlac
MD Anderson Cancer Center