464 Objectives With respect to the broad application of [18F-methyl]fluorocholine(FCH)and its ungoing process of marketing authorisation, there is a need for a safe, but also efficient and convenient way of routine quality control of FCH since no monograph is currently available for radiolabelled choline derivatives. Therefore, a GC- method should be developed and validated which allows the simultaneous quantitation of all chemical impurities and residual solvents as acetonitrile, ethanol, dibromomethane and DMAE. Methods Analytical GC has been performed with a GC-capillary column Optima 1701 (50 m x 0.32 mm) and a deactivated capillary pre-column phenyl-Sil (10 m x 0.32) in row with a flame ionisation detector (FID. The validation includes the following tests: specificity, range, accuracy, linearity, precision, limit of detection (LOD) and limit of quantification (LOQ) of all listed substances. Results The described GC-method has been successfully used for the quantitation of the listed chemical impurities. The specificity of the GC-separation has been proved by demonstrating that the appearing peaks are completely separated from each other and a resolution R ≥ 1,5 for the separation of the peaks could be achieved. The specified range derived from linearity studies confirmed that the analytical procedure provides an acceptable degree of linearity, accuracy and precision when applied to samples containing amounts of analyte within the specified range. For each substance a range from the LOD until 110-120 % of the specification limit could be demonstrated. The LOD and LOQ were determined and both values were much lower than the specification limit for all substances: ethanol (17.6 µg/ 61.6 µg), DMAE (1.7 µg/ 5.1 µg), acetonitrile (19.6 µg/ 63.4 µg)and dibromomethane (2.4 µg/ 7.1 µg). Conclusions An efficient and convenient GC-method for the quality control of FCH has been developed and validated meeting all acceptance criteria in terms of linearity, specificity, precision, accuracy as well as LOD and LOQ
The radionuclide bone scan is the cornerstone of skeletal nuclear medicine imaging. Bone scintigraphy is a highly sensitive diagnostic nuclear medicine imaging technique that uses a radiotracer to evaluate the distribution of active bone formation in the skeleton related to malignant and benign disease, as well as physiological processes. The European Association of Nuclear Medicine (EANM) has written and approved these guidelines to promote the use of nuclear medicine procedures of high quality. The present guidelines offer assistance to nuclear medicine practitioners in optimizing the diagnostic procedure and interpreting bone scintigraphy. These guidelines describe the protocols that are currently accepted and used routinely, but do not include all existing procedures. They should therefore not be taken as exclusive of other nuclear medicine modalities that can be used to obtain comparable results. It is important to remember that the resources and facilities available for patient care may vary.
With the development of new architectures and increasing abstraction came the realizations that a course in programming languages need not be based on any particular model of computation or paradigm but must provide a solid foundation in most commonly used programming paradigms. In this paper we discuss an effective way to introduce procedural, object oriented, logic and functional programming paradigms using the closed (supervised) laboratory approach.
Background: The association of subclinical hypothyroidism (SCH) with increased risk for cardiovascular disease is still controversial. This study aimed to examine coronary vascular reactivity by positron emission tomography (PET) in asymptomatic patients with SCH before and after levothyroxine (LT4) supplementation. Methods: Ten patients (7 women and 3 men; mean age 43±15 years) with untreated autoimmune SCH, defined by elevated levels of thyroid-stimulating hormone (mean TSH: 16.9±11.3 μU/mL), normal levels of free thyroxine (0.9±0.1 μg/mL), free triiodothyronine (3.2±0.4 pg/mL), and positive thyroid peroxidase antibodies were studied. Eight euthyroid subjects with similar low-risk cardiovascular risk profile served as controls. Myocardial blood flow (MBF) and coronary flow reserve (CFR) were quantitatively assessed with rest/stress N-13 ammonia PET at baseline and after 6 months of LT4 replacement therapy (given only to patients). Results: At baseline, stress MBF and CFR corrected (c) for rate pressure product (RPP) and myocardial vascular resistance (MVR) during stress were significantly reduced in SCH compared with controls (stress MBF: 2.87±0.93 vs. 4.79±1.16 mL/g/min, p=0.003; CFR: 2.6±0.73 vs. 4.66±1.38, p=0.004; MVR: 40.14±18.76 vs. 20.47±6.24 mmHg/mL/min, p=0.02). Supplementation therapy with LT4 normalized TSH in all subjects and was associated with an increase in CFR (2.6±0.73 vs. 3.81±1.19, p=0.003) and with a tendency toward a decrease in MVR. Differences in CFR between SCH and controls were also seen after correction of resting MBF for RPP. Conclusions: In asymptomatic subjects with SCH due to thyroid autoimmunity, coronary microvascular function is impaired and improves after supplementation with LT4. This may partially explain the increased cardiovascular risk attributed to SCH.
The aim of this paper was to compare the diagnostic performance of positron emission tomography/computed tomography (PET/CT) with fluorocholine (18F) (FCH) or fluoride(18F) (FNa) for the detection of bone metastasis in patients with prostate cancer complaining from osteoarticular pain, taking into account whether they were referred for initial staging or recurrence localization. The initial hypothesis was that FCH site-based specificity would be superior to that of F Na, with no loss in sensitivity.Forty-two patients were enrolled in this prospective study, underwent both PET/CTs and were then followed-up for at least 6 months. The standard of truth (SOT) about the presence/absence and location of bone metastasis could be determined in 40 patients, by 2 independent medical assessors, blinded to the results of both PET/CTs. The comparison was performed according to the guideline of the European Medicines Agency, i.e. based on the results of blind reading with SOT as reference.Bone extension was present in 22 patients and absent in 18. Patient-based performance for FCH vs. FNa was 91% vs. 91% for sensitivity, 89% vs. 83% for specificity and 90% vs. 88% for accuracy (no significant difference). Of 360 skeletal sites, 68 were malignant and 292 non-invaded. There was no significant difference in site-based performance in the group of patients referred at initial staging, but in the group of patients referred for suspicion of recurrence, FCH was significantly more specific than FNa (96% vs. 91%, P=0.033 with Obuchowski's correction) while sensitivity was the same, 89%.Both radiopharmaceuticals, based on a very different metabolic approach, showed good diagnostic performance. If FCH is available, it should be preferred in patients after initial treatment.
As projects increase in size and complexity, they become more difficult to handle. One of these large and complex projects is oil and gas projects. The current controlling processes of projects are not able to detect the problems in early phases of the project and are rather late leading to extra time and cost. One solution is to find symptoms of problems in the early phases. Due to the importance of drilling projects in upstream sector, the main objective of this research is to identify the early warning symptoms of problems in drilling projects and to find the relationships between selected early warnings with project outcomes and problems of these projects. To reach that aim, the early warnings have been recognized through literature review and interviews with experts. Then, case study analysis is performed to find the relationships between early warnings and project outcomes. All cases have been selected from previous completed drilling projects in one of the oil fields of Iran. Findings show that there is a relationship between early warnings, project outcomes and projects problems.
