11C-choline Positron Emission Tomography Research Articles

Recent developments in urologic oncology: positron emission tomography molecular imaging

Traditional morphologically based imaging modalities in uro-oncology are now being complemented by the functional and molecular imaging technique positron emission tomography (PET). This review highlights the most important recent developments. Prostate cancer: PET imaging with the new radiotracers 11C-choline, 18F-fluorocholine, and 11C-acetate show promising results. The role of anti-1-amino-3-18F-fluorocyclobutane-1-carboxylic acid remains to be elucidated further. 18F-fluoride PET is useful for the detection of bone metastases. Bladder cancer: 18F-fluorodeoxyglucose (FDG) PET/CT with delayed images after a diuretic and oral hydration may improve detection of locally recurrent or residual bladder tumours. Both 18F-FDG PET and 11C-choline PET may be useful for staging of bladder cancer. Renal cancer: 18F-FDG PET has a role in staging and restaging of the disease. Recently, 124I-cG250 PET has shown promising results in the detection of clear-cell renal carcinoma. Testicular cancer: 18F-FDG PET is useful in staging and follow-up after treatment. There are no important recent developments with new radiopharmaceuticals in testicular cancer. The utility of PET molecular imaging in uro-oncology expanded due to the new metabolic PET tracers with more favourable properties.

Metabolic Assessment of Gliomas Using11C-Methionine, [18F] Fluorodeoxyglucose, and11C-Choline Positron-Emission Tomography

Positron-emission tomography (PET) is a useful tool in oncology. The aim of this study was to assess the metabolic activity of gliomas using (11)C-methionine (MET), [(18)F] fluorodeoxyglucose (FDG), and (11)C-choline (CHO) PET and to explore the correlation between the metabolic activity and histopathologic features. PET examinations were performed for 95 primary gliomas (37 grade II, 37 grade III, and 21 grade IV). We measured the tumor/normal brain uptake ratio (T/N ratio) on each PET and investigated the correlations among the tracer uptake, tumor grade, tumor type, and tumor proliferation activity. In addition, we compared the ease of visual evaluation for tumor detection. All 3 of the tracers showed positive correlations with astrocytic tumor (AT) grades (II/IV and III/IV). The MET T/N ratio of oligodendroglial tumors (OTs) was significantly higher than that of ATs of the same grade. The CHO T/N ratio showed a significant positive correlation with histopathologic grade in OTs. Tumor grade and type influenced MET uptake only. MET T/N ratios of more than 2.0 were seen in 87% of all of the gliomas. All of the tracers showed significantly positive correlations with Mib-1 labeling index in ATs but not in OTs and oligoastrocytic tumors. MET PET appears to be useful in evaluating grade, type, and proliferative activity of ATs. CHO PET may be useful in evaluating the potential malignancy of OTs. In terms of visual evaluation of tumor localization, MET PET is superior to FDG and CHO PET in all of the gliomas, due to its straightforward detection of "hot lesions".

Is there a role for positron emission tomography imaging in the early evaluation of prostate cancer relapse?

The patient population with a rising prostate specific antigen (PSA) post-therapy with no evidence of disease on standard imaging studies currently represents the second largest group of prostate cancer patients. Little information is still available regarding the specificity and sensitivity of positron emission tomography (PET) tracers in the assessment of early biochemical recurrence. Ideally, PET imaging would allow one to accurately discriminate between local vs nodal vs distant relapse, thus enabling appropriate selection of patients for salvage local therapy. The vast majority of studies show a relatively poor yield of positive scans with PSA values < 4 ng ml(-1). So far, no tracer has been shown to be able to detect local recurrence within the clinically useful 1 ng ml(-1) PSA threshold, clearly limiting the use of PET imaging in the post-surgical setting. Preliminary evidence, however, suggests that 11C-choline PET may be useful in selecting out patients with early biochemical relapse (PSA < 2 ng ml(-1)) who have pelvic nodal oligometastasis potentially amenable to local treatment. The role of PET imaging in prostate cancer is gradually evolving but still remains within the experimental realm. Well-conducted studies comparing the merits of different tracers are needed.

11C‐Choline positron‐emission tomography/computed tomography and transrectal ultrasonography for staging localized prostate cancer

To evaluate and compare the role of (11)C-choline positron emission tomography (PET) and transrectal ultrasonography (TRUS) in the preoperative staging of clinically localized prostate cancer. Fifty-five consecutive patients with biopsy-confirmed prostate cancer had TRUS and (11)C-choline PET as a part of their clinical staging programme before radical retropubic prostatectomy (RP). The PET images were prospectively interpreted by a consensus decision of two nuclear medicine physicians and one radiologist with special expertise in the field. The TRUS was done by one experienced urologist. The criteria evaluated prospectively in each patient were extracapsular extension (ECE), seminal vesicle invasion (SVI) and bladder neck invasion (BNI). The results were compared with the histopathological findings after RP. At pathology, 32 patients were classified pT2, 16 as pT3a and three had pT3b lesions. In four patients the histopathological examination showed pT4 with BNI. The overall accuracy of PET in defining local tumour stage (pT2 and pT3a-4) was 70%; the overall accuracy by TRUS was 26%. PET was more sensitive than TRUS for detecting ECE (pT3a) and SVI (pT3b) in advanced stages, and in pT4 stages. The sensitivity and positive predictive value (PPV) (95% confidence interval) in stages pT3a-pT4 for PET were 36 (17-59)% and 73 (39-89)%. The sensitivity and PPV in stages pT3a-pT4 for TRUS were 14 (3-35)% and 100 (29-100)%. (11)C-choline PET and TRUS tended to understage prostate cancer. This series shows the current limited value of TRUS and PET for making treatment decisions in patients with clinically localized prostate cancer, especially if a nerve-sparing RP is considered. Treatment decisions should not be based on TRUS and (11)C-choline PET findings alone. In future studies, the combination of metabolic and anatomical information of PET and endorectal magnetic resonance imaging should be evaluated, as this might optimize the preoperative staging in prostate cancer.

Staging performance of carbon‐11 choline positron emission tomography/computed tomography in patients with bone and soft tissue sarcoma: Comparison with conventional imaging

The present study was conducted to compare the diagnostic accuracy between carbon-11 choline (11C-choline) positron emission tomography (PET)/computed tomography (CT) and conventional imaging for the staging of bone and soft tissue sarcomas. Sixteen patients who underwent 11C-choline PET/CT prior to treatment were evaluated retrospectively for staging accuracy. Conventional imaging methods consisted of 99,mTc-hydroxymethylene diphosphonate bone scintigraphy, chest CT and magnetic resonance imaging of the primary site. The images were reviewed and a consensus was reached by two board-certified radiologists who were unaware of any clinical or radiological information using hard-copy films and multimodality computer platform. Tumor stage was confirmed by histological examination and/or by an obvious progression in number and/or size of the lesions on follow-up examinations. Reviewers examining both 11C-choline PET/CT and conventional imaging classified T stage in all patients. Interpretation based on 11C-choline PET/CT, the Node (N) stage was correctly diagnosed in all patients, whereas the accuracy of conventional imaging in N stage was 63%. Tumor Node Metastasis (TNM) stage was assessed correctly with 11C-choline PET/CT in 15 of 16 patients (94%) and with conventional imaging in eight of 16 patients (50%). The overall TNM staging and N staging accuracy of 11C-choline PET/CT were significantly higher than that of conventional imaging (P < 0.05). 11C-choline PET/CT is more accurate than conventional imaging regarding clinical staging of patients with bone and soft tissue sarcomas. A whole body 11C-choline PET/CT might be acceptable for imaging studies of tumor staging prior to treatment.

11C-Choline Positron Emission Tomography/Computerized Tomography for Tumor Localization of Primary Prostate Cancer in Comparison With 12-Core Biopsy

(11)C-choline positron emission tomography is an innovative imaging technique for prostate cancer. We assessed the sensitivity of positron emission tomography used together with computerized tomography for intraprostatic localization of primary prostate cancer on a nodule-by-nodule basis, and compared its performance with 12-core transrectal biopsy. In 43 patients with known prostate cancer who had received positron emission tomography/computerized tomography before initial biopsy, we assessed sensitivity of positron emission tomography/computerized tomography for localization of nodules 5 mm or greater (those theoretically large enough for visualization) using radical prostatectomy histopathology as the reference standard. Comparison with transrectal ultrasound guided biopsy was based on sextant assessment of all cancer foci following sextant-by-sextant matching and reconstruction. Sensitivity/specificity of positron emission tomography/computerized tomography and magnetic resonance imaging for prediction of extraprostatic extension was also assessed. Positron emission tomography/computerized tomography showed 83% sensitivity for localization of nodules 5 mm or greater. At logistic regression analysis only nodule size appeared to influence sensitivity. At sextant assessment positron emission tomography/computerized tomography had slightly better sensitivity than transrectal ultrasound guided biopsy (66% vs 61%, p = 0.434) but was less specific (84% vs 97%, p = 0.008). For assessment of extraprostatic extension, sensitivity of PET/CT was low in comparison with magnetic resonance imaging (22% vs 63%, p <0.001). Positron emission tomography/computerized tomography has good sensitivity for intraprostatic localization of primary prostate cancer nodules 5 mm or greater. Positron emission tomography/computerized tomography and transrectal ultrasound guided biopsy show similar sensitivity for localization of any cancer focus. Positron emission tomography/computerized tomography does not seem to have any role in extraprostatic extension detection. Studies of diagnostic accuracy (as opposed to tumor localization) are needed in patients with suspected prostate cancer to see whether positron emission tomography/computerized tomography could have a role in not selected patients.

11C-choline positron emission tomography in bladder cancer: Report of four cases

Little work has been done with positive emission tomography (PET) in bladder tumors because high urinary excretion of (18)F-FDG makes visualization of the bladder tumor difficult. (11)C-choline has recently been reported as a new tracer which lacks urinary radioactivity. We report the result of (11)C-choline PET in four patients with invasive bladder tumors. In one case, (11)C-choline PET could detect bladder tumor effectively without urinary activity and bone metastasis despite negative bone scintigraphy. On the other hand, an intense accumulation of the tracer in the bladder hampered the interpretation on PET scanning in three patients. The mechanisms of the (11)C-choline accumulation in the bladder were reported to be due to inflammatory and proliferative changes in the mucosa of the bladder from previous catheterization or other factors. Further study is necessary to prove the value of (11)C-choline PET for detecting primary bladder cancer and bone metastasis.

633Diagnostic efficacy of 11C-choline positron emission tomography in patients scheduled for cystectomy

633Diagnostic efficacy of 11C-choline positron emission tomography in patients scheduled for cystectomy

Functional imaging in lhermitte-duclose disease

A comprehensive metabolic characterization of a patient with dysplastic gangliocytoma of the cerebellum or Lhermitte-Duclos Disease (LDD) is presented. Assessment using 2-deoxy-2-[18F]fluoro-D-glucose (FDG), carbon-11-labeled methionine (11C-MET), carbon-11-labeled choline (11C-Choline) positron emission tomography (PET), and 1H-proton magnetic resonance spectroscopy (MRS) was carried out in a 30-year-old Caucasian woman. FDG-PET revealed hypermetabolism of the tumor. 11C-MET-PET revealed moderate uptake and 11C-Choline showed no uptake. 1H-MRS demonstrated an elevated level of lactate and decreased levels of choline (Cho) and myoinositol. Functional imaging in LDD reflects the dual pathological features of neoplasm and hamartoma.

LONG-TERM HAZARD OF PROGRESSION AFTER RADICAL PROSTATECTOMY FOR CLINICALLY LOCALIZED PROSTATE CANCER: CONTINUED RISK OF BIOCHEMICAL FAILURE AFTER 5 YEARS

Cure from malignancy is commonly defined as a disease-free state lasting 5 years after treatment. We analyzed clinical and biochemical progression rates after radical prostatectomy for men with clinically localized prostate cancer with particular attention to recurrence beyond 5 years. Annual hazard rates of progression were calculated to determine the probability of recurrence at specific intervals following surgery. The records of 2,782 men with clinically localized prostate cancer (cT1-T2) undergoing radical prostatectomy between 1987 and 1993 were reviewed. All patients were treated in the prostate specific antigen (PSA) era so that serial followup PSA values were available from the time of surgery. Analysis was limited to patients who did not receive adjuvant treatment within 90 days of radical prostatectomy. Disease progression was defined as documented local recurrence, systemic progression and/or PSA 0.4 ng./ml. or greater. Lymph node positive cases were eliminated from analysis since almost all received adjuvant hormonal therapy. Annual hazard rates for progression were calculated using the formula: [No. events / No. patients at risk] x 100. Progression-free survival probabilities were determined using the Kaplan-Meier method. Pathological stage was pT2a-b, N0 (68%), pT3a, N0 (21%) and pT3b, N0 (11%). Biochemical progression-free survival at 5 and 10 years was 76% and 59%, respectively, for the entire study population while those with pathologically organ confined (pT2, N0) cancers had progression-free survival rates of 82% and 68% at 5 and 10 years, respectively. A total of 819 patients (29%) eventually had disease progression, including 160 (6%) with progression after 5 years. Annual hazard rates were highest during the first 2 years after radical prostatectomy for the entire population. Patients with adverse prognostic features (pT3b, PSA 10 ng./ml. or greater, Gleason score 8-10 and nondiploid cancers) had high initial hazard rates that decreased with time to lower levels. Those with pathologically organ confined cancer had low but constant hazard rates throughout followup. Although progression after radical prostatectomy usually occurs early, reflecting the impact of clinical under staging, a significant number of men, including those with organ confined cancers, will continue to have disease progression after 5 years. Patients undergoing radical prostatectomy should be subjected to long-term followup to allow the option of early intervention should progression occur.