Presentation on theme: "PET/CT: Improved Confidence in Imaging"— Presentation transcript:
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 StagingMore Accurate Surgical PlanningMore Accurate Guided BiopsyMore Accurate Radiation Therapy PlanningIMPROVED DIAGNOSTIC CONFIDENCE(for improved patient management)
3 History of Radiology and Cancer “50 Years of Imaging Form”Form = AnatomyAnatomy 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 MRMRCT
4 “Form” Strengths and Limitations Strengths …but Diagnostic Questions RemainClear delineation of form What is normal? Performance isless post operative due to distortionof normal anatomyAccurate detection and What is the mass? (fat? water? air?)localization of massesAccurate detection of lymph What is within the lymph nodes?nodes (present or absent) (benign or malignant?)Some small lesion What is the cause?identificationHave small tumor foci been over- looked (especially if surrounded bynormal tissues)?
5 “Form” Strengths and Limitations Treatment Planning Questions Also RemainWhat 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 limitationsof anatomic imaging alone
6 “Function” Imaging – FDG-PET FDG-PET Strengths …butHigh sensitivity for detection of abnormal cell metabolismReal-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 RemainWhere 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/ModalityDiagnostic CT scanner (high quality images of anatomy)PET scanner (high quality images of function)Computer and software to fuse/display imagesNo patient motion between studies (or very little)
10 Where Form meets Function What is PET/CT?normal heartWhere Form meets FunctionThe best of detectionand localizationBetter thanPET or CT alonelung 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 StagingNSCLC5mm lymph node metNo 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 patientPET/CT demonstrates a solitary met in the liverUpstages patient to Stage IVHao Vuong, MD, Baptist Hospital of MiamiDespite 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 metastasesPET shows right paratracheal uptake suggesting nodal metastasisPET/CT shows metastasis to normal sized right paratracheal nodeProven by biopsy.
16 More Accurate Guided Biopsy Head and Neck cancer patientPET/CT identifies a nasopharyngeal squamous cell carcinomaConfirms 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 History63 YOF, nasopharyngeal cancer 5 yrs priorPresents with progressive dysphagia and neck painPanendoscopy negative, MRI unrevealingPET/CT FindingsFDG accumulation in the posterior aspect of the larynx (SUV= 15.8) – not shown hereSmall focus with mild FDG uptake (SUV = 1.2) corresponding to a small lymph node in the left neck.Impact to Patient ManagementDeep 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 CarcinomaCT is clearly abnormalPET is mildly abnormalWhen combined: Worrisome for brochioloalveolar carcinomaConfirmed by biopsy
20 Characterization and Localization CT shows precise lesion size, shape and locationPET shows increased FDG uptakeNon-Small-Cell Lung Cancer
21 Confirmation of Benign Nodule CT shows pulmonary nodule which is large enough to image with PETPET shows no increased tracer uptakeNo disease present
22 Better than PET or CT alone Diagnostic Accuracy with Respect to Tumor Stage (40 Pts)Non-Small-Cell Lung CancerClassificationCorrect butImaging Method Correct Equivocal IncorrectCT alone 58% 20% 22%PET alone 40% 40% 20%Visual correlation of 65% 12% 22%PET and CTIntegrated 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 CancerClassificationCorrect butImaging Method Correct Equivocal IncorrectCT alone 59% 5% 35%PET alone 49% 38% 14%Visual correlation of 59% 11% 30%PET and CTIntegrated PET-CT 81% 3% 16%Lardinois, et. al., NEJM 2003, 348:
24 Improved CertaintyHistory of MelanomaWhat 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)TonsilsSubmandibular and Parotid GlandsCricoarytenoid 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 devices40-50% increased scan volume capacityImproved cost-effectiveness with improved productivity20 min emission20 min transmission20 sec transmissionPET OnlyPET/CT40 min20 min
28 Patient preparation Fasting for four hours Patient changed into gown and pantsAll metallic objects are removedCheck glucose levels< 200 mg/dl2 bottles of Readi-CAT (Barium sulphate 1.3 %) oral CT contrast prior to injection of 18F-FDGWe 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 pantsAll metallic objects are removedCheck 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 PreparationPatient is positioned head first and supine on the tableScanning begins from meatus of ear to mid thighShallow breathing during the CTCurrently, 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 imaging3 minute emission per FOV for Melanoma imaging (more FOVs)10-20 minute emission for 3D brain imagingCT Scan ProtocolHelicalHigh SpeedPitch 622.5 mm/rotation5 mm slices140 kV & 80mA—varies50 cm DFOV512 x 512 matrix
31 PET/CT (Fusion) Workstations Fusion occurs on the PET/CT scanner workstationHi-Res CT images are minimized to 128x128 matrixImages can be displayed in any plane or sliceMIP (3D PET images) and CT Scout views are providedEntegra images here
32 Where Form meets Function PET is Very Accurate.PET/CT is even more Accurate.Disease StagingSurgical PlanningGuided BiopsyRadiation Therapy PlanningPET/CTBetter than PET or CT aloneEditor: Richard L. Wahl, M.D.Division of Nuclear MedicineDepartment of RadiologyJohns Hopkins Medical InstitutesOther Contributors:Hao VuongBaptist Hospital of MiamiJack ZifferHomer MacapinlacMD Anderson Cancer Center