Molecular positron emission tomography and PET/CT imaging in urological malignancies

OBJECTIVES: Positron emission tomography (PET) provides unique insights into molecular pathways of diseases. PET using [F-18]-fluorodeoxyglucose (FDG) has gained increasing acceptance for the diagnosis, staging, and treatment monitoring of various tumour types. The aim of this review is to provide an update on the current status of molecular PET and PET/CT imaging in urological malignancies. METHODS: The current literature on PET and PET/CT imaging was reviewed and summarized for prostate cancer, bladder cancer, renal cell carcinoma, and germ cell tumours. RESULTS: Depending on the radiotracer used, PET offers diagnostic information based on glucose, choline or amino acid metabolism and has also been applied to imaging tumour cell proliferation and tissue hypoxia in urological malignancies. The diagnostic performance of FDG-PET is hampered by the renal excretion of FDG and by the low metabolic activity often seen in tumours such as prostate cancer. However, new PET tracers including radiolabelled choline and acetate may offer an alternative approach. There is consistent evidence that FDG-PET provides important diagnostic information in detecting metastatic and recurrent germ cell tumours and it might offer additional information in the staging and restaging of bladder and renal cancer. CONCLUSIONS: Although PET imaging has been shown to be a clinically useful tool, its application in urological malignancies still needs to be fully determined by larger prospective trials. The introduction of novel PET radiopharmaceuticals along with the new technology of PET/CT will likely change the future role of molecular imaging in urological malignancies.     

Positron emission tomography for urological tumours

For urological tumours, positron emission tomography (PET) is currently most useful in testicular cancer. In patients with residual masses or raised marker levels after treatment, PET is both sensitive and specific for detecting recurrent disease, at suspected and unsuspected sites. Although fewer studies are available it also appears to be useful for staging at diagnosis, although this requires further investigation. Prostate cancer imaging has been more variable, with studies showing that PET cannot reliably differentiate between tumour and hypertrophy. It is not as good as a bone scan for defining bone metastases. In renal cancer, PET can be used to define the primary tumour, providing better staging of local recurrence than computed tomography (CT), and to define metastatic disease. There are few studies in bladder cancer, and despite excretion of the tracer via the bladder in early studies, it has better results than CT or magnetic resonance imaging for local staging; again it can detect metastases. Overall, the place of PET in urological tumours is developing, with the strongest areas undoubtedly being testicular and renal cancer. Tracers other than fluorodeoxyglucose are being examined and are providing further information.     

Stellenwert der Positronenemissionstomographie bei urologischen Tumoren

Positron emission tomography/computed tomography (PET/CT) is widely used for imaging urological neoplasms. This overview should help the urologist actively involved in oncology to assess the value of PET or PET/CT in each tumor entity. Besides prostate, testicular, renal, and bladder cancer less common urological malignancies like penile carcinoma and retroperitoneal masses are discussed. Differences in using PET/CT for primary diagnosis, staging, or restaging are outlined separately. Appropriate indications for the use in clinical practice are cited.     

18F-脱氧葡萄糖正电子发射计算机断层显像CT检查在前列腺癌诊断和分期中的应用价值

目的 评价18F-脱氧葡萄糖(18F-FDG)正电子发射计算机断层显像CT检查(PET/CT)在前列腺癌诊断和分期中的应用价值.方法 经手术或穿刺活检病理证实为前列腺癌患者40例,年龄52 ～ 78岁,平均67岁.其中T24例,T316例,T420例.行18F-FDG PET/CT及99Tcm-MDPECT骨显像检查,统计PET/CT显像对前列腺癌原发灶、淋巴结转移及骨转移诊断的敏感性,对比分析PET/CT显像及99Tcm-MDPECT骨显像对骨转移的诊断效果.结果 40例患者中,18F-FDG PET/CT检查显示前列腺局部结节状放射性浓聚17例,对原发灶诊断敏感性为43％.17例淋巴结转移患者中CT检查发现8例,18F-FDG PET/CT检查发现15例,诊断敏感性为88％,其中5例患者因PET/CT检查改变了临床分期以及治疗方案.18F-FDG PET/CT对骨转移诊断的敏感性与99Tcm-MDP骨显像相近,但特异性(95％)和准确率(96％)均明显高于99Tcm-MDP骨显像,其中6例患者因PET/CT检查改变了临床分期,2例改变了治疗方案.结论 18F-FDG PET/CT对前列腺癌淋巴结转移和骨转移有较高诊断价值,对前列腺的分期具有特殊优势,可为临床医生制定治疗方案提供可靠依据.     

~(18)F-FDG PET/CT显像在泌尿系肿瘤中的临床应用

18F-脱氧葡萄糖正电子发射断层显像/CT技术(18F-FDG PET/CT)显像在多种恶性肿瘤的诊断、鉴别诊断、分期、随访监测、疗效与预后评估中起重要作用,但是其在泌尿系肿瘤中却因为18F-FDG由泌尿系统排泄而影响观察,肾细胞癌与前列腺癌原发肿瘤病灶则表现为少摄取或不摄取18 F-FDG而呈现假阴性表现。本文旨在探讨18F-FDG PET/CT显像在泌尿系统肿瘤中的潜在临床应用价值。     

Positron‐emission tomography/computed tomography (PET/CT) in the initial staging of primary rectal cancer

Objective The aim of this study was to assess the role of ¹⁸flourodeoxyglucose positron‐emission tomography/computed tomography (PET/CT) in the initial staging of primary rectal adenocarcinoma. Method A total of 20 patients with adenocarcinoma of the rectum were assessed with both PET/CT and conventional staging (CT chest/abdomen/pelvis, MRI rectum). Discordance with conventional imaging and incidental findings on PET were recorded and the patients presented to a colorectal cancer multidisciplinary team to assess management changes. Patients were followed up so that discordant or incidental findings could be verified by intra‐operative examination, imaging or histology where possible. Results Positron‐emission tomography/computed tomography correctly identified the primary tumour in all 20 patients. Comparing PET/CT with conventional staging modalities, there were 11 discordant or incidental findings in nine patients (45%). This resulted in a potential change in stage in 30% (four patients downstaged and two upstaged). PET/CT suggested additional neoplastic pathology in three patients and excluded the same in two patients. The incidental neoplastic findings were of minor clinical significance and one was eventually deemed false positive. While PET/CT resulted in potential management changes in five patients (25%), no changes in surgical management occurred. When tumours were grouped according to conventional stage, PET/CT resulted in fewer changes in stage in stage I (0%), compared with stages II to IV (43%) (P = 0.08). Conclusion Positron‐emission tomography/computed tomography provides additional information to conventional staging in primary rectal cancer. This information produced minor management changes in this study and did not effect surgical management. PET/CT may be most appropriately used selectively in more advanced stages and where indeterminate findings exist with conventional staging.     

MRI/PET Imaging in elevated PSA and localized prostate cancer: a narrative review

ObjectiveTo review the recent milestones in MRI and PET based imaging and evaluate their evolving role in the setting of elevated PSA as well as localized prostate cancer.BackgroundThe importance of multiparametric MRI (mpMRI) and PET based imaging for the diagnosis and staging of prostate cancer cannot be understated. Accurate staging has become another significant milestone with the use of PET scans, particularly with prostate specific radiotracers like 68-Gallium Prostate Specific Membrane Antigen (68Ga-PSMA). Integrated PET/MRI systems are commercially available and can be modulated to evaluate the unique needs of localized as well as recurrent prostate cancer.MethodsA literature search was performed using PubMed and Google Scholar using the MeSH compliant and other keywords that included prostate cancer, PSA, mpMRI, PET CT, PET/MRI.ConclusionsmpMRI has now established itself as the gold-standard of local prostate imaging and has been incorporated into international guidelines as part of the diagnostic work-up of prostate cancer. PSMA PET/CT has shown superiority over conventional imaging even in staging of localized prostate cancer based on recent randomized control data. Imaging parameters from PET/MRI have been shown to be associated with malignancy, Gleason score and tumour volume. As mpMRI and PSMA PET/CT become more ubiquitous and established; we can anticipate more high-quality data, cost optimization and increasing availability of PET/MRI to be ready for primetime in localized prostate cancer.     

Clinical usefulness of 18-fluorodeoxyglucose positron emission tomography in the management of patients with nonpancreatic periampullary neoplasms

BACKGROUND: 18-Fluorodeoxyglucose positron emission tomography (18-FDG PET) has been investigated for the diagnosis and staging of gastrointestinal malignancies including pancreatic adenocarcinoma. The aim of this study was to examine the clinical usefulness of 18-FDG PET in the diagnosis and follow-up evaluation of patients with periampullary neoplasms. METHODS: Twenty-five patients underwent whole-body 18-FDG PET and abdominal computed tomography (CT). Pathologic confirmation was obtained in all patients by surgical resection or biopsy examination. The 18-FDG PET was analyzed visually and semiquantitatively using the standard uptake value (SUV). Positivity was assumed when a focal uptake occurred with an SUV of 2.5 or greater. RESULTS: Between January 1998 and December 2003, 14 ampullary, 7 bile duct, and 4 duodenal tumors were included in the study. PET showed increased focal uptake in 22 patients (88%): 11 of 14 (79%) ampullary tumors, and 100% of bile duct and duodenal tumors. PET showed a focal uptake in 11 of 12 patients without detectable mass at CT scan, and lymph node metastases in 6 patients. An SUV value of 2.7 discriminated adenomas or noninvasive cancers (n = 6) from invasive malignancies (n = 14). Follow-up evaluation including CT scan and PET was performed in 12 patients: PET showed recurrent disease not seen by CT in 4 patients, confirmed CT findings in 6 patients, and showed an unsuspected primary lung cancer in 1 patient and colon cancer in another patient. CONCLUSIONS: 18-FDG PET is very sensitive for detecting periampullary neoplasms. It may be useful to differentiate benign or borderline lesions from invasive tumors when no mass has been identified by traditional imaging. Finally, it is very useful in the follow-up evaluation of resected patients to identify recurrent disease or other malignancies.     

Impact of F18-fluorodeoxyglycose positron emission tomography/computed tomography on the management of resectable pancreatic tumours

Background: Positron emission tomography/computed tomography (PET/CT) using F18‐fluorodeoxyglucose has been shown to be valuable in the management of malignant disease. The aim of this study is to investigate the impact of this technique on the management of patients with resectable pancreatic tumours. Methods: Thirty‐six patients with 37 potentially resectable pancreatic tumours on diagnostic CT imaging underwent PET/CT scans. Operative findings, histological reports and/or clinical follow‐up served as standard of reference. The impact of PET/CT on patient management was estimated by calculating the percentage of patients whose treatment plan was altered due to PET/CT. Results: Pancreatic adenocarcinoma was diagnosed in 30 patients, neuroendocrine tumours in 3, mass‐forming pancreatitis in 3 and serous cystadenoma in 1. The median standard uptake (max) value was 5.0 (range 2.2–12.0). Sensitivity and specificity of detecting extrapancreatic metastatic disease were 73% and 100%, respectively. Three occult liver metastases were detected at laparotomy following negative PET/CT. PET/CT findings influenced the management of 8 (22%) patients – 3 with liver metastases, 3 with bone metastases, 1 with lymph node metastases and 1 by identifying the benign appearance of the pancreatic tumour. Conclusion: PET/CT achieves a significant diagnostic impact in detecting extrapancreatic metastatic disease. F18‐fluorodeoxyglucose PET/CT appears to be useful in assessing suspicious pancreatic masses.     

Current value of positron emission tomography for prostate cancer follow-up

Positron emission tomography (PET) is a non-invasive nuclear medicine technology which uses radiotracers and cameras slightly different from the ones used in other nuclear medicine tests. Most current indications are for oncological diseases; in nephrology-urology its use has been reduced because of the characteristics of the most commonly used radiotracer, 18F-fluor deoxiglucose (18F-FDG, a glucose analogue), which is excreted by the kidney, limiting the interpretation of the study in urologic malignancies. Currently, 18F-choline is a promising radiotracer for both staging and restaging, especially if hybrid PET/CT scan devices are used. New radiotracers will be needed in the evolution of PET to obtain information about more specific aspects of prostate carcinoma that will modify therapy and follow-up.     

Diagnostic imaging in the preoperative management of lung cancer

Surgical resection is the accepted standard of care for patients with non-small cell lung cancer (NSCLC). Several imaging modalities play central roles in the detection and staging of the disease. The aim of this review is to evaluate the utility of computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET) and PET/CT for NSCLC staging. Radiographic staging refers to the use of CT as a non-invasive diagnostic technique. However, while the vast majority of patients undergo only CT, CT is a notoriously inaccurate means of tumor and nodal staging in many situations. PET/CT clearly improves the staging, particularly nodal staging, compared to CT or PET alone. In addition, as a result of the increased soft-tissue contrast, MRI is superior to CT for distinguishing between tissue characteristics. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), which is a minimally invasive technique, also has pathological diagnostic potential. Extensive research and the resultant improvements in the understanding of genetics, histology, molecular biology and oncology are transforming our understanding of lung cancer, and it is clear that imaging modalities such as CT, MRI, PET and PET/CT will have an important role in its preoperative management. However, thoracic surgeons should also be aware of the limitations of these techniques.     

Combined 18F‐fluorocholine and 18F‐fluoride positron emission tomography/computed tomography imaging for staging of high‐risk prostate cancer

Study Type – Diagnosis (cohort) Level of Evidence 2a What's known on the subject? and What does the study add? Positron emission tomography/computed tomography (PET/CT) with choline and fluoride for the detection of metastases in patients with prostate cancer have each been evaluated, with mixed results. Choline PET/CT has been evaluated against pelvic lymphadenectomy, generally with a low sensitivity but a high specificity; however, the study populations have been heterogenous. Fluoride PET/CT has been evaluated against other imaging methods, such as bone scan, single photon emission CT and MRI, and has been shown to have high specificity as well as sensitivity for bone metastases, but there are no studies with biopsy verification. This is the first study that evaluates the clinical use of both choline and fluoride PET/CT on the same patients in a well‐defined population of patients with high‐risk prostate cancer.

OBJECTIVE

• ? To investigate how often positron emission tomography/computed tomography (PET/CT) scans, with both ¹⁸F‐fluorocholine and ¹⁸F‐fluoride as markers, add clinically relevant information for patients with prostate cancer who have high‐risk tumours and a normal or inconclusive planar bone scan.

PATIENTS AND METHODS

• ? Patients with prostate cancer with prostate specific antigen (PSA) levels between 20 and 99 ng/mL and/or Gleason score 8–10 tumours, planned for treatment with curative intent based on routine staging with a negative or inconclusive bone scan, were further investigated with a ¹⁸F‐fluorocholine and a ¹⁸F‐fluoride PET/CT.
• ? None of the patients received hormonal therapy before the staging procedures were completed.

RESULTS

• ? For 50 of the 90 included patients (56%) one or both PET/CT scans indicated metastases.
• ? ¹⁸F‐fluorocholine PET/CT indicated lymph node metastases and/or bone metastases in 35 patients (39%).
• ? ¹⁸F‐fluoride PET/CT was suggestive for bone metastases in 37 patients (41%).
• ? In 18 patients (20%) the PET/CT scans indicated widespread metastases, leading to a change in therapy intent from curative to non‐curative.
• ? Of the patients with positive scans, 74% had Gleason score 8–10 tumours. Of the patients with Gleason score 8–10 tumours, 64% had positive scans.

CONCLUSIONS

• ? PET/CT scans with ¹⁸F‐fluorocholine and ¹⁸F‐fluoride commonly detect metastases in patients with high‐risk prostate cancer and a negative or inconclusive bone scan.
• ? For 20% of the patients the results of the PET/CT scans changed the treatment plan.

     

Combined contrast-enhanced computed tomography and 18-fluoro-2-deoxy-D-glucose-positron emission tomography in the diagnosis and staging of non-small cell lung cancer

We present the current optimal uses and limitations of positron emission tomography/computed tomography (PET/CT) as it relates to the diagnosis and staging of non-small cell lung cancer (NSCLC). PET/CT demonstrates increased accuracy in the workup of solitary pulmonary nodules for malignancy compared with CT alone, and we discuss its benefits and limitations. We review pitfalls in measured standardized uptake values of lung lesions caused by respiratory artifacts, the lower sensitivity for detection of small lung nodules on non-breath-hold CT, and the benefits of obtaining an additional diagnostic CT for the maximum sensitivity of lung nodule detection. There are limitations of quantitatively comparing separate PET/CT examinations from different facilities with standardized uptake values. As for staging, we describe how PET/CT supplements clinical tumor-nodes-metastases (ie, TNM) staging, as well as mediastinoscopy, endobronchial ultrasound, and endoscopic ultrasound, which are the gold standard pathologic staging methods. We touch on the 7th edition TNM staging system based on the work by the International Association for the Study of Lung Cancer, an anatomically based staging method.     

PET/CT Fusion Scan Enhances CT Staging in Patients with Pancreatic Neoplasms

Background  The role of fusion positron emission tomography/computed tomography scans (PET/CT) in staging of patients with pancreatic neoplasms (PN) is poorly defined. PET/CT may serve as an adjunct to standard imaging by increasing occult metastases detection. The purpose of this study was to assess the additional value, in relation to computed tomography (CT), of PET/CT imaging for patients with PN. Methods  Eighty-two patients with potentially resectable PN underwent staging with PET/CT and CT of the chest and abdomen. Sensitivity of diagnosing pancreatic cancer by PET/CT avidity was evaluated. The sensitivity of detecting metastases was compared between PET/CT, standard CT, and the combination of PET/CT and CT. The impact of PET/CT on patient management was estimated by calculating the percentage of patients whose treatment plan was altered due to PET/CT. Results  The sensitivity and specificity of PET/CT in diagnosing pancreatic cancer were 89% and 88%, respectively. Sensitivity of detecting metastatic disease for PET/CT alone, standard CT alone, and the combination of PET/CT and CT were 61%, 57%, and 87%, respectively. Findings on PET/CT influenced the clinical management in seven patients (11%), two with a supraclavicular lymph node (LN), two occult liver lesions, two peritoneal implants, and one peri-esophageal LN. Conclusion  This study evaluated PET/CT in the initial work-up of patients with PN. PET/CT increased sensitivity (87%) for detection of metastatic disease when combined with standard CT. In invasive cancer, PET/CT changed the management in 11% of our patients. PET/CT should be considered in the initial work-up of patients with potentially resectable pancreatic lesions.     

Limitations in the use of 18F-FDG PET in the pre-operative staging of gastric cancer: A case series

IntroductionPositron emission tomography (PET) is a mainstay in the preoperative evaluation of various cancers. In gastric cancer however, its role in the initial staging remains contentious. Presented is a case series of three gastric patients wherein the use of fluorodeoxyglucose (18F-FDG) PET/CT (computer tomography) as part of the initial staging was inconsequential to treatment, demonstrating its limited role in the staging of primary gastric cancer.MethodsWe analyzed retrospective data from 12/1/2010 to 10/31/2016 of patient with gastric cancer whose initial staging included a PET/CT. Only patients 18 years and older with gastric and gastro-oesophageal junction cancers were included. The data was derived from a single institution. Management of patients involved both an academic institution and a community practice.ResultsOf the three cases reported, an FDG-avid mass with minimal FDG uptake was reported in a single case and no FDG-avid lesion was reported in the other two. Neither of the patients underwent an endoscopic ultrasound for lack of availability.ConclusionWhile various imaging studies such as endoscopic ultrasound have an established role in the initial staging, the role of FDG-PET is yet to be established and its routine use remains contentious. Based on our clinical experience and review of the literature, we believe FDG-PET/CT imaging is of limited clinical and cost effective value in the initial staging workup of gastric cancer.     

Positron emission tomography (PET) in the urooncological evaluation of the small pelvis

Positron emission tomography (PET) with the use of (¹⁸F)2-fluoro-d-2-desoxyglucose (FDG) has been investigated to be a highly sensitive and specific imaging modality in the diagnostic of primary and recurrent tumors and in the control of therapies in numerous non-urologic cancers. The aim of this review is to validate the significance of PET as a diagnostic tool in malignant urological tumors of the small pelvis. A systematic review of the current literature concerning the role of PET for malignant prostate, testicular and bladder tumors was carried out. The data indicate no additional role for PET in comparison with conventional imaging in tumor detection and local staging for prostate, bladder or testicular cancer. Tumor recurrence in prostate cancer seems to be more effectively identified with acetate and choline than with FDG, but this effect is more pronounced with higher PSA values. The value of PET in the identification of metastatic disease in either tumor entity can not be finally outlined as the clinical data are partly missing, controversial or in the process of evaluation. FDG-PET can be regarded as accepted imaging modality in the restaging of seminomatous germ cell tumors after chemotherapy.     

Advantages of positron emission tomography over computed tomography in mediastinal staging of non-small cell lung cancer

BACKGROUND: New treatment algorithms in early stage non-small cell lung cancer (NSCLC) involving preoperative chemotherapy require accurate clinical staging of the mediastinum. This study compares the accuracy of 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scanning with that of computed tomography (CT) scanning in the clinical staging of non-small cell lung cancer. MATERIALS AND METHODS: A retrospective review was performed on 52 patients with NSCLC who were evaluated with both CT and PET scans. All patients had their mediastinal lymph nodes sampled by mediastinoscopy or at the time of thoracotomy for pulmonary resection. Each imaging study was evaluated separately and correlated with histopathologic results. RESULTS: For detecting mediastinal metastases the sensitivities of PET and CT scans were 67 and 50%, respectively; specificities were 91 and 65%, respectively; accuracies were 88 and 63%, respectively; positive predictive values were 50 and 16%, respectively; negative predictive values were 95 and 88%, respectively. PET scans were significantly better than CT scans at detecting mediastinal metastases (PET, 4/8; CT, 3/19) (P = 0.01). CONCLUSIONS: PET scanning is superior to CT scanning for clinical staging of the mediastinum in NSCLC. A more confident decision regarding stratification of patients into current treatment algorithms can be made when the decision is based on PET scanning rather than the current "gold standard" of CT scanning.     

Preoperative lymph-node staging of invasive urothelial bladder cancer with 18F-fluorodeoxyglucose positron emission tomography/computed axial tomography and magnetic resonance imaging: correlation with histopathology

OBJECTIVE: The treatment and prognosis of bladder cancer are based on the depth of primary tumour invasion and the presence of metastases. A highly accurate preoperative tumour, node, metastasis (TNM) staging is critical to proper patient management and treatment. This study retrospectively investigated the value of 1?F-fluorodeoxyglucose (FDG) positron emission tomography/computed axial tomography (1?F-FDG PET/CT) and magnetic resonance imaging (MRI) for preoperative N staging of bladder cancer. Material and methods. From June 2006 to January 2008, 48 consecutive patients diagnosed with bladder cancer were referred to preoperative staging including MRI and 1?F-FDG PET/CT. Eighteen out of 48 patients underwent radical cystoprostatectomy including removal of lymph nodes for histology, and were included in the study. Values of 1?F-FDG PET/CT and MRI for regional N staging were compared to histopathology findings, the gold standard. Results. 1?F-FDG PET/CT and MRI were performed in 18 patients. The specificities for detection of lymph-node metastases for MRI and 1?F-FDG PET/CT were 80% (n = 15) and 93.33% (n = 15), respectively. The negative predictive values were 80% (n = 15) and 87.5% (n = 16) for MRI and 1?F-FDG PET/CT, respectively. The differences in specificity and negative predictive values were not statistically significant. Conclusions. No significant statistical difference between 1?F-FDG PET/CT and MRI for preoperative N staging of urothelial bladder cancer was found in the study. However, the trend of the data indicates an advantage of 1?F-FDG PET/CT over MRI. Larger prospective studies are needed to elucidate the role of 1?F-FDG PET/CT in N staging of bladder cancer.     

Positron emission tomography does not add to computed tomography for the diagnosis and staging of pancreatic cancer

BACKGROUND: Positron emission tomography (PET) has been proposed for pancreatic cancer diagnosis and staging. METHODS: 112 patients with suspected pancreatic cancer underwent 18F-fluoro-2-deoxy-D-glucose gamma camera PET and computed tomography (CT), of whom 62 also had laparoscopic ultrasonography and 70 underwent abdominal exploration for potential resection. The final diagnosis was malignancy in 78 and benign disease in 34 patients (25 with chronic pancreatitis). RESULTS: The diagnostic sensitivity and specificity for PET were 73 and 60% compared to 89 and 65% for CT respectively (Cohen's kappa = 0.59). In 30 patients CT was equivocal with cancer in 14 and benign disease in 16. PET correctly diagnosed 13 of these patients (cancer in 6 and benign disease in 7), interpreted 4 as equivocal (cancer in 3 and benign disease in 1) but was incorrect in the remaining 13 patients (cancer in 5 and benign disease in 8). The sensitivity and specificity for detecting small volume metastatic disease were 20 and 94% for CT and 22 and 91% for PET, respectively. CONCLUSION: PET had a similar accuracy to that of CT for imaging pancreatic cancer but it did not provide any additional information in patients with equivocal CT findings and currently would seem of little benefit for the staging of pancreatic cancer.