Objectives: Positron emission tomography (PET) using fluorodeoxyglucose (FDG) is useful for restaging renal cell carcinoma (RCC) and detecting metastatic diseases but is less satisfactory for detecting primary disease. We evaluated whether the integration of computed tomography (CT) scans with the PET system could increase the applicability of FDG-PET for RCC. Methods: The MEDLINE databases were searched for relevant studies published since 2001. Two reviewers independently assessed the methodological quality of each study identified. We then performed a meta-analysis of the sensitivity and specificity of FDG-PET findings as reported in all the selected studies. Results: Fourteen studies were eligible for inclusion. The pooled sensitivity and specificity of FDG-PET were 62% and 88% respectively, for renal lesions. For detecting extra-renal lesions, the pooled sensitivity and specificity of FDG-PET were 79% and 90%, respectively, based on the scans, and 84% and 91% based on the lesions. The use of a hybrid FDG-PET/CT to detect extra-renal lesions increased the pooled sensitivity and specificity to 91% and 88%, respectively, with good consistency. Conclusions: For RCC, combining the FDG-PET and CT systems is helpful for detecting extra-renal metastasis rather than renal lesions. The hybrid PET/CT system has comparable sensitivity and specificity with PET in detecting extra-renal lesions of RCC. Advances in knowledge: The FDG-PET and PET/CT systems are both useful for detecting extra-renal metastasis in renal cell carcinoma.

Our report discloses different sex- and age-related brain metabolism. Decreased brain metabolism with aging in males and females is similar to findings reported in previous literatures. However, whether declined brain function or volume with aging causing metabolic changes is unknown and should be further evaluated. Nevertheless, the sex-related differences are possibly compatible with the historical observation of better performance in visual-spatial tasks in males than females.

The EBT2 film together with a flatbed scanner is a convenient dosimetry QA tool for verification of clinical radiotherapy treatments. However, it suffers from a relatively high degree of uncertainty and a tedious film calibration process for every new lot of films, including cutting the films into several small pieces, exposing with different doses, restoring them back and selecting the proper region of interest (ROI) for each piece for curve fitting. In this work, we present a percentage depth dose (PDD) method that can accurately calibrate the EBT2 film together with the scanner non-uniformity correction and provide an easy way to perform film dosimetry. All films were scanned before and after the irradiation in one of the two homemade 2 mm thick acrylic frames (one portrait and the other landscape), which was located at a fixed position on the scan bed of an Epson 10 000XL scanner. After the pre-irradiated scan, the film was placed parallel to the beam central axis and sandwiched between six polystyrene plates (5 cm thick each), followed by irradiation of a 20 × 20 cm² 6 MV photon beam. Two different beams on times were used on two different films to deliver a dose to the film ranging from 32 to 320 cGy. After the post-irradiated scan, the net optical densities for a total of 235 points on the beam central axis on the films were auto-extracted and compared with the corresponding depth doses that were calculated through the measurement of a 0.6 cc farmer chamber and the related PDD table to perform the curve fitting. The portrait film location was selected for routine calibration, since the central beam axis on the film is parallel to the scanning direction, where non-uniformity correction is not needed (Ferreira et al 2009 Phys. Med. Biol. 54 1073-85). To perform the scanner non-uniformity calibration, the cross-beam profiles of the film were analysed by referencing the measured profiles from a Profiler™. Finally, to verify our method, the films were exposed to 60° physical wedge fields and the compositive fields, and their relative dose profiles were compared with those from the water phantom measurement. The fitting uncertainty was less than 0.5% due to the many calibration points, and the overall calibration uncertainty was within 3% for doses above 50 cGy, when the average of four films were used for the calibration. According to our study, the non-uniformity calibration factor was found to be independent of the given dose for the EBT2 film and the relative dose differences between the profiles measured by the film and the Profiler were within 1.5% after applying the non-uniformity correction. For the verification tests, the relative dose differences between the measurements by films and in the water phantom, when the average of three films were used, were generally within 3% for the 60° wedge fields and compositive fields, respectively. In conclusion, our method is convenient, time-saving and cost-effective, since no film cutting is needed and only two films with two exposures are needed.

The purpose of the present study was to conduct a systematic review and meta-analysis of the published literature to evaluate the diagnostic performance of fluorine-18 2-fluoro-2-deoxy-D-glucose (18F-FDG) PET in the pretherapeutic assessment of nodal staging in patients with colorectal cancer (CRC). We conducted a systematic MEDLINE search of articles in the published literature (last update, February 2012). Two reviewers independently assessed the methodological quality of each study. We estimated pooled sensitivity, specificity, summary receiver operating characteristic curves, and summary likelihood ratios. A total of 409 patients from 10 studies were analyzed. The pooled estimates of sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of 18F-FDG PET [PET/computed tomography (CT)] in the detection of pretherapeutic lymph node involvement in patients with CRC were 42.9% [95% confidence interval (CI): 36.0-50.0%], 87.9% (95% CI: 82.6-92.0%), 2.82 (95% CI: 1.96-4.07), and 0.69 (95% CI: 0.62-0.78), respectively. There is no solid evidence to support the routine clinical application of 18F-FDG PET (PET/CT) in the pretherapeutic evaluation of lymph node status in patients with CRC. However, 18F-FDG PET (PET/CT) could be used to strengthen the possibility of suspected metastatic lymph nodes detected by other imaging modalities.

SUMMARYTo evaluate the prevalence of coronary artery disease (CAD) in patients with spinal cord injury (SCI), 47 clinically asymptomatic SCI patients received thallium-201 myocardial perfusion single photon emission computed tomography (Tl-201 SPECT) after dipyridamole administration for the diagnosis of CAD. There were 4 groups as follows; group 1: 13 patients with quadriplegia and complete SCI, group 2: 11 patients with quadriplegia and incomplete SCI, group 3: 11 patients with paraplegia and complete SCI, and group 4: 12 patients with paraplegia and incomplete SCI. There were no significant differences in sex distribution, ages, SCI duration, or CAD risk factors among the SCI patients in the 4 groups. All Tl-201 SPECT images were interpreted by the agreement of 2 experienced nuclear medicine physicians without prior knowledge of the patients' histories. A total of 30 of 47 (63.8%) SCI patients had abnormal Tl-201 SPECT findings. Among the 4 groups of SCI patients, those in groups 1 and 4 had the significantly highest and lowest prevalences of abnormal Tl-201 SPECT findings, respectively. We concluded that combined quadriplegia and complete SCI is an important CAD risk factor in SCI patients based on the objective evidence of intravenous dipyridamole cardiac stress testing with Tl-201 SPECT. (Int Heart J 2006; 47: 325-330) Key words: Spinal cord injury, Thallium-201 myocardial perfusion single photon emission computed tomography THERE is a cluster of multiple risk factors for coronary artery disease (CAD) among individuals with spinal cord injury (SCI), 1) but there is little information available on the prevalence of CAD in this population. SCI patients tend to have an increased percentage of body fat and have sedentary life styles. These individuals may not have symptoms despite significant CAD, partially due to their reduced level of activity. SCI patients often undergo rehabilitation programs, exercise training, metabolic testing, and surgical procedures without having their From the

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The 13C-urea breath test (13C-UBT) is a non-invasive method for detecting Helicobacter pylori. This study was performed to determine the cutoff value and evaluate the sensitivity and specificity of 13C-UBT in Taiwan. 13C-Urea (100 mg of 99% 13C-labeled urea) was dissolved in 50 ml sterile water for the test. The test meal for delaying gastric emptying was 100 ml fresh milk. Patients fasted for at least 6h. A baseline breath sample was collected 5 min after they had the test meal. Two other samples were collected at 15 and 30 min after the patients ingested the 13C-urea. The test was evaluated in 352 patients after routine upper gastrointestinal endoscopy, and the urease test, culture, and histopathology were taken as the gold standards for detecting H. pylori. According to the receiver operating characteristic (ROC) curves, we chose values of 2.8 and 4.2 excess delta 13CO2 per mil as the cut-off values for 15 and 30 min, respectively, post 13C-urea. The sensitivity and specificity of 13C-UBT were 99% and 93% at 15 min, and 98% and 93% at 30 min post 13C-urea, respectively. The 13C-UBT breath test is an efficient non-invasive method of high sensitivity and high specificity for detecting H. pylori infection. We suggest that the use of fresh milk as the test meal and the detection of excess delta 13CO2 15 min after the ingestion of 13C-urea are suitable for the clinical use of 13C-UBT. This test is simple and rapid.

Spatial homogeneity was significantly improved via the calibration method described here. This technique is both convenient and time-efficient because it does not require cutting the film, and only two exposures are necessary.