Future of Thoracic PET Scanning Geoffrey B. Johnson, MD, PhD, Patrick J. Peller, MD, Bradley J. Kemp, PhD, Jay H. Ryu, MD, FCCP  CHEST  Volume 147, Issue 1, Pages 25-30 (January 2015) DOI: 10.1378/chest.14-1612 Copyright © 2015 The American College of Chest Physicians Terms and Conditions

Figure 1 A, B, Quantitative measurements of tumor burden. Patient A and B have a similar tumor type, grade, stage, and SUVmax. However, they have very different tumor burden, and the MTV and TLG predict a worse prognosis for patient A (each panel has maximum intensity projection [MIP] images, axial PET scan, and axial PET/CT scan with automated volumetric regions of interest drawn around sites of malignancy based on a standard uptake value threshold). MTV = metabolic tumor volume; Sq = squamous; SUVmax = maximum standard uptake value; TLG = total lesion glycolysis. CHEST 2015 147, 25-30DOI: (10.1378/chest.14-1612) Copyright © 2015 The American College of Chest Physicians Terms and Conditions

Figure 2 A, B, Use of 18 F-fluorodeoxyglucose (FDG)-PET/CT scanning for inflammatory conditions. Images show a systemic pattern of inflammatory FDG activity that suggests IgG4-related disease (IgG4-RD aka autoimmune pancreatitis) and not cancer (axial fused PET/CT scan [A] and MIP image [B]). In this 72-y-old man, there is biopsy-proven IgG4-RD in the salivary glands, pancreas, periaortic retroperitoneum, and prostate. In any one location, the FDG activity does not help differentiate cancer from inflammatory IgG4-RD. FDG-PET/CT scanning is not currently approved by the Center for Medicare and Medicaid Services for the evaluation of known inflammatory conditions. However, these conditions can be identified on FDG-PET/CT scans in patients suspected of having cancer. See Figure 1 legend for expansion of other abbreviation. CHEST 2015 147, 25-30DOI: (10.1378/chest.14-1612) Copyright © 2015 The American College of Chest Physicians Terms and Conditions

Figure 3 New PET scan radiotracers will open up new imaging opportunities. Here is an example of metastatic carcinoid imaged with 68Ga-DOTATATE PET/CT scan (showing a MIP image, axial PET scan, axial PET/CT scan, and enhanced axial diagnostic CT scan with arrows on liver metastases of different sizes). This is an octreotide analog that can be used with higher-resolution PET/CT imaging rather than 111In-octreotide single photon emission CT/CT scanning. As seen here, metastases in the liver as small as 4 mm can be seen above background. For the evaluation of small FDG-PET/CT scan-negative lung nodules and staging of carcinoid, 68Ga-DOTATATE and 68Ga-DOTANOC have great promise. These imaging agents are not yet approved by the Food and Drug Administration. See Figure 1 and 2 legends for expansion of abbreviations. CHEST 2015 147, 25-30DOI: (10.1378/chest.14-1612) Copyright © 2015 The American College of Chest Physicians Terms and Conditions

Figure 4 A-C, Recent advances in image reconstruction result in improved PET image resolution. Recently, Food and Drug Administration-approved image processing with Bayesian PL (A) iterative reconstruction shows more accurate measurement of metabolic activity of a 5-mm metastatic nodule than current state-of-the art ToF (B) and older 3D reconstruction (C). With PL, the 5-mm nodule is clearly more active than the mediastinal blood pool in this patient with many liver and lung metastases (A shows FDG-PET scan MIP with arrow on the 5-mm nodule, axial PET scan, and axial PET/CT scan). PL = penalized likelihood; SUVm = maximum standard uptake value; ToF = time of flight. See Figure 1 legend for expansion of other abbreviation. CHEST 2015 147, 25-30DOI: (10.1378/chest.14-1612) Copyright © 2015 The American College of Chest Physicians Terms and Conditions