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.     

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.     

Role of positron emission tomography in urological oncology

??Positron emission tomography (PET) is a diagnostic tool using radiotracers to show changes in metabolic activities in tissues. We analysed the role of PET and PET/computed tomography (CT) in the diagnosis, staging, and follow-up of urological tumours. ??A critical, non-structured review of the literature of the role of PET and PET/CT in urological oncology was conducted. ??PET and PET/CT can play a role in the management of urological malignancies. For prostate cancer, the advances in radiotracers seems promising, with novel radiotracers yielding better diagnostic and staging results than 18F-fluorodeoxyglucose (18F-FDG). In kidney cancer, PET and PET/CT allow a proper diagnosis before the pathological examination of the surgical specimen. For testis cancer, PET and PET/CT have been shown to be useful in the management of seminoma tumours. In bladder cancer, these scans allow a better initial diagnosis for invasive cancer, while detecting occult metastases. ??PET and its combined modality PET/CT have shown their potential in the diagnosis of urological malignancies. However, further studies are needed to establish the role of PET in the management of these diseases. Future applications of PET may involve fusion techniques such as magnetic resonance imaging with PET.     

Funktionelle Bildgebung beim Harnblasenkarzinom

Computed tomography (CT) represents the current standard imaging modality in muscle invasive bladder cancer; however, local tumor and lymph node staging is often impaired. Magnetic resonance imaging (MRI) with diffusion-weighted sequences, determination of apparent diffusion coefficient (ADC) values or utilization of supraparamagnetic iron nanoparticles potentially exhibits advantages in the assessment of local tumor and lymph node involvement and therefore might play a role in the staging of bladder tumor in the future. Likewise, positron emission tomography (PET) with the currently used tracers ¹⁸F fluorodeoxyglucose (¹⁸F-FDG), ¹¹C-choline and ¹¹C-acetate is being investigated in bladder cancer patients, mostly in combination with diagnostic CT. Although promising results could be obtained for PET/CT investigations to some extent, the true value cannot be determined at present.     

Bedeutung der radiologischen Bildgebung für die Lymphknotenchirurgie urologischer Malignome

This review illustrates the relevance of computed tomography (CT) and magnetic resonance imaging (MRI) for detecting or excluding lymph node metastases in urological malignancies. Although radiological assessment of lymph node metastases is well established in renal cell and testicular cancer, it is unreliable in prostate, bladder, and penile cancer. MR lymphography has shown promising results in these tumors, but because marketing authorization for the iron oxide contrast agent is lacking, it is not clinically applicable. Percutaneous CT-guided biopsy in the retroperitoneum and pelvis is introduced as an alternative in the histological exploration of suspicious lymph nodes.     

Fluorodeoxyglucose Positron Emission Tomography in Cutaneous Squamous Cell Carcinoma: Retrospective Analysis of 12 Patients

BACKGROUND: Whole-body 18F-fluorodeoxyglucose positron emission tomography (FDG PET) has been used for whole-body imaging modality in detecting malignancy in clinical oncology. However, only a few reports of FDG PET in skin cancers have been described, except for melanoma and lymphoma. OBJECTIVE: To report on the usefulness of FDG PET as a baseline workup study for patients with cutaneous squamous cell carcinoma (SCC). METHODS: There were 12 cases of SCC (9 cases with high-risk SCC). Of the 12, FDG PET was performed for staging in 11 patients and for restaging in 1 patient 1 year after wide excision. RESULTS: Primary lesions were detected in nine cases (83.3%), lymph node involvement in three cases (25.0%), and distant. organ (lung) involvement in one case (8.3%). In one patient whose primary lesion was positive, stomach cancer with involvement of adrenal glands, omentum, and lymph nodes was incidentally detected. All of the patients with high-risk SCC showed FDG uptakes of the primary lesions, and the patients with FDG uptakes in lymph nodes and distant organ had high-risk SCC. CONCLUSION: There have been no comparative studies on the cost-effectiveness between sentinel lymph node biopsy and FDG PET in SCC patients. However, considering the noninvasiveness and thoroughness in checking the whole body, including distant organs, FDG PET may have clinical value as a baseline workup study for patients with high-risk SCC.     

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.     

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.     

Comparative efficacy of positron emission tomography with FDG and computed tomographic scanning in preoperative staging of non-small cell lung cancer

OBJECTIVE: To determine the sensitivity, specificity, and accuracy of positron emission tomography with 2-fluorine-18-fluorodeoxyglucose (PET-FDG) in the preoperative staging (N and M staging) of patients with lung cancer. The authors wanted to compare the efficacy of PET scanning with currently used computed tomography (CT) scanning. MATERIALS AND METHODS: Results of whole-body PET-FDG imaging and CT scans were compared with histologic findings for the presence or absence of lymph node disease or metastatic sites. Sampling of mediastinal lymph nodes was performed using mediastinoscopy or thoracotomy. RESULTS: PET-FDG imaging was significantly more sensitive, specific, and accurate for detecting N disease than CT. PET changed N staging in 35% and M staging in 11% of patients. CT scans helped in accurate anatomic localization of 6/57 PET lymph node abnormalities. CONCLUSION: PET-FDG is a reliable method for preoperative staging of patients with lung cancer and would help to optimize management of these patients. Accurate lymph node staging of lung cancer may be ideally performed by simultaneous review of PET and CT scans.     

FDG-PET/CT for the Preoperative Lymph Node Staging of Invasive Bladder Cancer

Background

Locoregional lymph node metastasis is an important prognostic factor in patients with bladder cancer. Multimodal treatment, depending on preoperative stage, may improve survival. The standard imaging modalities for staging (computed tomography [CT] or magnetic resonance imaging [MRI]) have an accuracy range of 70–90% for lymph node staging. A more accurate preoperative diagnostic test could improve survival rates even more.

Objective

To determine whether the use of 2-deoxy-2 [F] fluoro-D-glucose (FDG) positron emission tomography (PET) in combination with CT (FDG-PET/CT) can increase the reliability of preoperative lymph node staging in patients with nonmetastatic invasive bladder cancer (T2 or higher, M0) or recurrent high-risk superficial disease (T1G3 with or without Tis, M0).

Design, setting, and participants

Fifty-one patients underwent a preoperative FDG-PET/CT between April 2004 and December 2007. Independent of the result for lymph node status, all patients underwent a radical cystectomy and an extended lymphadenectomy. The FDG-PET/CT and CT results were compared with the definitive pathologic results.

Measurements

Among the 51 patients, 13 patients had metastatically involved locoregional lymph nodes, diagnosed on histopathology. In six patients, these nodes demonstrated increased FDG uptake on PET. In seven patients, PET/CT did not diagnose the positive lymph nodes. PET/CT was false positive in one patient.

Results and limitations

For the diagnosis of node-positive disease, the accuracy, the sensitivity, and the specificity of FDG-PET/CT were 84%, 46%, and 97%, respectively. When analysing the results of CT alone, there was accuracy of 80%, sensitivity of 46%, and specificity of 92%. The use of FDG-PET/CT is hampered by technical limitations.

Conclusions

We found no advantage for combined FDG-PET/CT over CT alone for lymph node staging of invasive bladder cancer or recurrent high-risk superficial disease.     

Positronenemissionstomographie (PET) zur Diagnostik und zum Therapiemonitoring bei urologischen Tumoren

Positron emission tomography (PET) using ((18)F)2-fluoro-D-2-desoxyglucose (FDG) has been shown to be a highly sensitive and specific imaging modality in the diagnosis of primary and recurrent tumors and in the control of therapies in numerous non-urologic cancers. It was the aim of this review to validate the significance of PET as a diagnostic tool in malignant tumors of the urogenital tract. A systematic review of the current literature concerning the role of PET for malignant tumors of the kidney, testicles, prostate, and bladder was carried out. The role of FDG PET for renal cell cancer can be seen in the detection of recurrences after definitive local therapy and metastases. The higher sensitivity of PET in comparison to other therapeutic modalities (CT, ultrasound, MRI) in recurrent and metastatic renal cell cancer suggests a supplemental role of this diagnostic procedure to complement other imaging modalities.The clinical value of PET is established for the identification of vital tumor tissue after chemotherapy of seminomatous germ cell tumors. This diagnostic method has little significance for primary tumor staging and diagnosis of non-seminomatous germ cell tumor because of the high probability of false-negative results in adult teratomas. FDG PET is not sensitive enough in the diagnosis of primary or recurrent tumors in prostate or bladder cancer. Also PET did not prove to be superior to conventional bone scintigram in the detection of mostly osteoblastic metastases in prostate cancer. The recent use of alternative tracers, which are partly not eliminated by urinary secretion (acetate, choline) has increased the sensitivity and specificity of PET also in this tumor entity so that further clinical investigations are needed to validate these technical modifications in their significance for this imaging modality. PET appears to be sufficiently evaluated only for the diagnostic follow-up of patients with seminomatous germ cell tumors after chemotherapy to regard it is the diagnostic tool of first choice. For all other tumors of the urogenital tract this proof is still awaited.     

膀胱部分切除术配合辅助化疗治疗盆腔淋巴结阴性的肌层浸润性膀胱癌临床疗效及其预后影响因素分析

目的 研究膀胱部分切除术+化疗对盆腔淋巴结阴性的肌层浸润性膀胱癌的治疗效果,报告这一治疗方法的有效性,并探讨影响其预后的因素。方法 本研究选取了2008年2月至今到我院肿瘤科实行了膀胱部分切除术并联合辅助化疗的肌层浸润性膀胱癌病人的临床有关资料,共纳入50例作为治疗组。同时选取了同一时期接受根治性膀胱切除术治疗的肌层浸润性膀胱癌病人50例作为对照组,并认真收集其临床资料。将治疗组与对照组的有效率进行对比分析。为分析影响盆腔淋巴结阴性的肌层浸润性膀胱癌的危险因素,笔者通过logistic回归进行进一步分析。结果 研究所得结果显示治疗组的有效率为87.50%,对照组的有效率为83.33%,两组比较得知,治疗组与对照组在有效率方面并不存在统计学差异（P＞0.05）,但通过分期比较,我们所得高选择性患者治疗组的有效率明显高于对照组,且有统计学意义（P＜0.05）。logistic回归分析测得病理分级（P=0.001,P＜0.05）和病理分期（P=0.002,P＜0.05）为盆腔淋巴结阴性的肌层浸润性膀胱癌发病的独立危险因素。结论 本研究对膀胱部分切除术配合辅助化疗的治疗方法加以对比显示,膀胱部分切除术配合辅助化疗相比根治性膀胱切除术治疗的肌层浸润性膀胱癌在所有病理分级中并没有优势,但在高选择性患者中采用膀胱部分切除术配合辅助化疗的治疗方法更有疗效。病理分级和病理分期为影响盆腔淋巴结阴性的肌层浸润性膀胱癌的独立危险因素,应得到充分关注,进而提高盆腔淋巴结阴性的肌层浸润性膀胱癌的预后效果。     

PET—CT在前列腺癌诊断与临床分期的应用

目的探讨PET—CT应用于前列腺癌诊断及分期的临床价值。方法2008年1月至2011年1月新疆自治区人民医院泌尿外科收治前列腺肿瘤病例中,病理类型最终确诊为前列腺癌者有47例接受了全身PET—CT检查。检查范围包括前列腺原发肿瘤、区域淋巴结及全身脏器,将PET—CT结果参照手术／病理结果进行评价分析。结果47例患者中1例未发现原发病灶,此外PET—CT与常规检查各有1例假阴性,准确性均高达95．7％,差异无统计学意义。35例I、Ⅱ期患者中18例髂血管淋巴结转移,PET-CT检查的敏感性59．6％、特异性81％、准确性70．3％,优于B超、磁共振检查;PET—CT发现4例患者合并远处转移并经穿刺证实,准确性100％。结论PET—CT对于发现前列腺癌原发肿瘤、区域淋巴结转移均优于B超、磁共振检查,且对于远处转移具有较精确的检测能力,对于前列腺癌术前诊断及分期有较好的临床价值。     

<Superscript>99m</Superscript>Tc-HDP bone scintigraphy and <Superscript>18</Superscript>F-sodiumfluoride PET/CT in primary staging of patients with prostate cancer

Introduction/Aim

Correct staging of patients with prostate cancer is important for treatment planning and prognosis. Although bone scintigraphy with ^99mTc-phosphonates (BS) is generally advised for staging by guidelines in high risk prostate cancer, this imaging technique is hampered by a high rate of inconclusive results and moderate accuracy. Potentially better imaging techniques for detection of bone metastases such as ¹⁸F-sodiumfluoride PET/CT (NaF PET/CT) are therefore being evaluated. In this observational cohort study we evaluate the performance and clinical impact of both BS and NaF PET/CT in primary staging of patients with prostate cancer.

Methods

The first of two cohorts consisted of patients who received a BS while the second included patients who received a NaF PET/CT for primary staging of prostate cancer. For both cohorts the number of positive, negative and equivocal findings, calculated diagnostic performance of the imaging modality in terms of sensitivity and specificity, as well as the impact on clinical management were studied. The ranges of the diagnostic performance were calculated both assuming that equivocal findings were positive and assuming that they were negative for bone metastases. For the NaF PET/CT cohort the number of patients with signs of lymph node metastases on low dose CT were also recorded, including the impact of these findings on clinical management.

Results

One-hundred-and-four patients underwent NaF PET/CT, whereas 122 patients underwent BS. Sensitivities of 97–100 and 84–95% and specificities of 98–100 and 72–100% were found on a patient basis for detection of bone metastases with NaF PET/CT and BS, respectively. Equivocal findings warranted further diagnostic procedures in 2% of the patients in the NaF cohort and in 16% in the BS cohort. In addition NaF PET/CT demonstrated lymph node metastases in 50% of the included patients, of which 25% showed evidence of lymph node metastases only.

Conclusion

Our data indicate better diagnostic performance of NaF PET/CT compared to BS for detection of bone metastases in primary staging of prostate cancer patients. Less equivocal findings are encountered with NaF PET/CT. Moreover, NaF PET/CT has additional value over BS since lymph node metastases are encountered frequently.

     

Axillary staging using positron emission tomography in breast cancer patients qualifying for sentinel lymph node biopsy

Axillary lymph node dissection (ALND) is the standard of care for nodal staging of patients with invasive breast cancer. Due to significant somatic and psychological side effects, replacement of ALND with less invasive techniques is desirable. The goal of this study was to evaluate the clinical usefulness of axillary lymph node (ALN) staging by means of positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) in breast cancer patients qualifying for sentinel lymph node biopsy (SLNB). FDG-PET was performed within 1 week before surgery in 24 clinically node-negative breast cancer patients with tumors smaller than 3 cm. Sentinel lymph nodes (SLNs) were identified by preoperative lymphoscintigraphy following peritumoral technetium 99m-labeled colloid albumin injection, and by intraoperative gamma detector and blue dye localization. Following SLNB, a standard ALND was performed. Serial sectioning and immunohistochemistry of the SLN as well as standard histologic examination of the non-SLN was performed. FDG-PET detected all primary breast cancers. Staging of ALNs by PET was accurate in 15 of 24 patients (62.5%), whereas PET staging was false negative in 8 of 10 node-positive patients and false-positive in 1 patient. The sensitivity, specificity, positive predictive value, and negative predictive value of FDG-PET for nodal status was 20%, 93%, 67%, and 62%, respectively. The mean diameter of false-negative ALN metastases was 7.5 mm (range 1-15 mm). Lymph node staging using FDG-PET is not accurate enough in clinically node-negative patients with breast cancer qualifying for SLNB and should not be used for this purpose.     

The Role of Lymphadenectomy in Radical Cystectomy

Detection of lymph node metastases in patients undergoing radical cystectomy and pelvic lymph node dissection (PLND) for bladder cancer indicates poor prognosis. For pretreatment assessment of lymph node status, computed tomography and magnetic resonance imaging are generally performed, both of which show a low sensitivity of approximately 30%. Newer imaging techniques are being developed; however, it will take time until they can be used in everyday clinical practice. Therefore, PLND remains the only reliable method for lymph node staging in the pelvis. The extent of PLND remains a matter of discussion, but a recent study mapping the lymphatic drainage from the bladder suggests that the template for an appropriate PLND at cystectomy should include the external iliac, obturator, and internal iliac region (lateral and medial to the internal iliac vessels) as well as the common iliac vessels up to the uretero-iliac junctions bilaterally. Additionally, the lymph nodes of the fossa of Marcille should be removed. Questions remain about whether it is worthwhile to resect the few draining lymph nodes between the uretero-iliac junctions and the inferior mesenteric artery with regard to both the increased risk of complications and the injury to the autonomic sympathetic nerves. In addition, PLND at the time of radical cystectomy not only is associated with more accurate staging but also allows removal of undetected micrometastases in patients with bladder cancer. Evidence is growing that extended PLND in patients with bladder cancer may confer a survival benefit for node-positive and node-negative patients without increasing morbidity.     

PET staging of mediastinal lymph nodes in thoracic oncology

There is an extensive and growing body of literature about the role of positron emission tomography (PET) in the management of non-small cell lung cancer and esophageal cancer. This article focuses on the use of PET in mediastinal staging of these common thoracic malignancies. PET is the most accurate noninvasive approach to staging mediastinal lymph nodes in non-small cell lung cancer. The role of PET in mediastinal lymph node staging in esophageal cancer is less clear, since it has been largely supplanted by endoscopic ultrasonography. A review of the evidence for and against the use of PET in mediastinal staging is provided and the use of PET in practice is discussed.     

Novel imaging modalities for lymph node imaging in urologic oncology

Accurate lymph node staging in genitourinary (GU) malignancies is important for planning an appropriate treatment and establishing an accurate prognosis. This article discusses the novel imaging techniques for detection of metastases in various GU malignancies, including prostate, bladder, penile, and testicular cancers. Discussion includes nuclear medicine techniques of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT), (11)C-choline and (18)F-choline PET/CT, and ProstaScint scanning, as well as sentinel lymph node mapping. Magnetic resonance (MR) techniques include lymphotropic nanoparticle-enhanced MR imaging and diffusion-weighted MR imaging.     

Visualization of prostate cancer with 11C-choline positron emission tomography

BACKGROUND AND OBJECTIVE: Visualization of prostate cancer with positron emission tomography (PET) using 2-[18F]-2-deoxy-D-glucose (FDG) as radiopharmaceutical is limited by the low uptake of FDG in the tumor and by radioactivity excreted into the bladder. More specific PET radiopharmaceuticals would be welcome. Carbon-11 labeled choline (CHOL) is a new radiopharmaceutical potentially useful for tumor imaging as it is incorporated in the cell membranes as phosphatidylcholine. We prospectively studied the visualization of prostate cancer using CHOL PET. METHODS: A total of 25 consecutive patients with histologically proven prostate cancer and five patients with a benign prostate were included. PET images were performed with an ECAT HR(+) using 400MBq CHOL. Data acquisition was started at 5 minutes post-injection. Attenuation-corrected images were evaluated visually. Standardized uptake values (SUV) were calculated of the normal prostate gland and of the prostate tumor tissue. RESULTS: The normal prostate was visualized with a mean SUV of 2.3 (range 1.3-3.2). The primary tumor could be visualized with a mean SUV of 5.0 (range 2.4-9.5). Lymph node metastases >5mm could be identified. Non-specific uptake of CHOL was noticed in the intestines. Little to no radioactivity in the bladder was observed. CONCLUSION: Carbon-11-choline is avidly taken up in prostate cancer, both primary tumor and lymph node metastases, in the virtual absence of urinary radioactivity. These results confirm the early results obtained by others and permit further clinical research on the value of CHOL PET as a metabolic imaging technique in areas where conventional imaging have a limited sensitivity.