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

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)

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

“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)?

“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

“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

“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)?

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

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)

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

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.

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, 348:2500-07.

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

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.

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.

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.

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.

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

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

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

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

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, 348:2500-07

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, 348:2500-07

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

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

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

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

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.

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

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

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

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