3Post Prandial Scan57 year old man with stage IV left tonsillar scca treated with chemoradiation 21 months ago. Patient was lost to follow-up until he was referred for PET/CT. Coronal images show low FDG uptake in the brain, and high uptake in the heart and skeletal muscles.
5Fasting Scan in a Diabetic 51 year old man with colon polyps and a stricture referred for PET/CT to evaluate for possible malignancy. Fasting blood glucose level = 289 mg/dL. Coronal images show a good quality scan with normal FDG biodistribution.
6Hyperglycemia69 year old man with 2.3 cm RUL NSC lung cancer. FBS = 309 mg/dL. No insulin was given. Coronal images show a good quality scan with high FDG tumor uptake (max SUV 5.4)
7Insulin Effect on FDG uptake 63 year old man with 5 cm RUL adenocarcinoma. FBS = 299 mg/dL; 90 minutes after 15u of reg insulin IV FBS = 179 mg/dL at which time FDG was injected. Coronal images show a “muscle scan” with faint tumor uptake (max SUV = 2.0)
8False Positive FDG PET PhysiologicBenign NeoplasmAdenomaInflammatoryGranuloma, sarcoid, rheumatoidMiscellaneousProsthesis, graftsFractures
13Brown Fat • What is brown fat? • Methods to reduce FDG uptake ReassuranceHeatSedativesBeta blockers
14Adenoma74 yr old man with seizures and recent cognitive disorder
15Adenoma70 yr old man 2 months post chemoXRT for R piriform sinus cancer stage 3, T3N2M0.
16Adenoma63 y/o man 4 months post chemoXRT for R tonsil cancer T2N1M0
17Adenoma Adrenal adenoma SUV adrenal 4.0 SUV liver 2.2 51 yr old man with colon cancer treated with rectosigmoid colectomy and adjuvant chemotherapy.
18Adenoma82 year old man with wt loss and liver mass
19Question 1Which of the following neoplasms have been associated with focal FDG uptake in the colon?Hyperplastic polypb. Adenomatous polypc. Adenocarcinomad. All of the above
20Question 1 The correct answer is d. All of the above Gollub et al. Combined CT Colonography and 18F-FDG PET of Colon Polyps: Potential Technique for Selective Detection of Cancer and Precancerous Lesions. AJR Am J Roentgenol Jan;188(1):130-8.Friedland et al. 18-Fluorodeoxyglucose positron emission tomography has limited sensitivity for colonic adenoma and early stage colon cancer. Gastrointest Endosc Mar;61(3):d. All of the above
21Nodular Hyperplasia74 y/o man with metastatic disease to neck from unknown primary, now NED after chemoXRT
22Infection68 year old man with solitary lung nodule. Biopsy: aspergillosis3
23Granulomatous Disease 62 year old man with hilar and mediastinal adenopathy. Biopsy: sarcoidosis
29Volume AveragingGollub et al. J Nucl Med 2007;48:
30Problems with PET/CT Patient movement Respiratory misregistration Attenuation correction
31Patient Movement• Head movementSecure head, or use head holder
32Respiratory Misregistration variationPartial expiration best:“Breathe in, exhale, don’t breathe”from Ben Yeh MD, UCSF
33Respiratory Misregistration Sureshbabu and Mawlawi. J Nucl Med Technol 2005;33:
34Question 2 Respiratory misregistration in PET/CT is minimized when CT is performed in end inspirationb. CT is performed in mid expirationc. CT is performed in end expirationd. CT is performed during quiet breathing
35Question 2 The correct answer is b. CT is performed in mid expiration Sureshbabu W, Mawlawi O. PET/CT Imaging Artifacts. J Nucl Med Technol 2005;33:
36Attenuation Correction Sureshbabu and Mawlawi. J Nucl Med Technol 2005;33:
37Attenuation Correction Sureshbabu and Mawlawi. J Nucl Med Technol 2005;33:
38Summary• False negative FDG PET can be reduced by careful patient selection for appropriateness and proper preparation• False positive FDG PET can be reduced by correlation with CT and knowledge of potential pitfalls
39Summary • CT artifacts can be avoided by optimizing technique • PET/CT artifacts can be reduced by proper patient preparation and instructions