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@#Neuroendocrine tumours (NETs) are a category of neoplasm that is characterised by its phenotypic and heterogeneity. The occurrence of this type of neoplasm in the nasal cavity and paranasal sinuses is extremely rare accounting for only 0.2-0.8% of all cancers. NET tends to expresses somatostatin receptors (SSTR) and owning to this unique characteristic, molecular imaging has been able to detect these tumours using radiolabelled somatostatin analogue agent. Gallium-68 (Ga-68) DOTATATE PET/CT is an example of SSTR imaging and has been shown to be of importance in the assessment and staging of NET. We present a case of a rare sphenoid sinus NET in a 45-year-old gentleman whom initially presented with persistent left eye pain which led to visual loss. We described the utilization of Ga-68 DOTATATE PET/CT in the diagnosis and staging of this patient which in turn dictated treatment approach.
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@#Objective: To identify regions of the brain affected during cognitive working memory during tasks to assess attention, planning and decision making among military aviation personnel who have chronic intermittent exposure to high altitude environment. Method: A case-control study was conducted in the Universiti Putra Malaysia among eight military personnel, four of whom had chronic intermittent exposure to high altitude training. They were divided into two groups, chronic intermittent exposure group (CE) (n=4) and a control group (n=4). They underwent a task-based functional magnetic resonance imaging (fMRI) that utilised spatial working memory task to objectively evaluate the neural activation in response to the Tower of London paradigm. Each correct answer was given a score of one and the maximum achievable score was 100%. Results: A consecutive dichotomised group of CE (4/8) and control (4/8) of age-matched military aviation personnel with a mean age of 37.23±5.52 years; showed significant activation in the right middle frontal gyrus (MFG). This in turn was positively correlated with response accuracy. A significant difference in the response accuracy was noted among both the groups at p<0.05. Conclusion: At the minimum results of power analysis of this preliminary fMRI study, our group of aviation personnel who had chronic intermittent exposure to hypobaric hypoxic environment, did not have any significant decrease in cognitive function namely attention, decision-making and problem solving compared to controls during a working memory task
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BACKGROUND: Kidneys and urinary bladder are common physiologic uptake sites of 18fluorine-fluorodeoxyglucose (18F-FDG) causing increased exposure of low energy ionizing radiation to these organs. Accurate measurement of organ dose is vital as 18F-FDG is directly exposed to the organs. Organ dose from 18F-FDG PET is calculated according to the injected 18F-FDG activity with the application of dose coefficients established by International Commission on Radiological Protection (ICRP). But this dose calculation technique is not directly measured from these organs; rather it is calculated based on total injected activity of radiotracer prior to scanning. This study estimated the 18F-FDG dose to the kidneys and urinary bladder in whole body positron emission tomography/computed tomography (PET/CT) examination by comparing dose from total injected activity of 18F-FDG (calculated dose) and dose from organs activity based on the region of interest (ROI) (measured dose). METHODS: Nine subjects were injected intravenously with the mean 18F-FDG dose of 292.42 MBq prior to whole body PET/CT scanning. Kidneys and urinary bladder doses were estimated by using two approaches which are the total injected activity of 18F-FDG and organs activity concentration of 18F-FDG based on drawn ROI with the application of recommended dose coefficients for 18F-FDG described in the ICRP 80 and ICRP 106. RESULTS: The mean percentage difference between calculated dose and measured dose ranged from 98.95% to 99.29% for the kidneys based on ICRP 80 and 98.96% to 99.32% based on ICRP 106. Whilst, the mean percentage difference between calculated dose and measured dose was 97.08% and 97.27% for urinary bladder based on ICRP 80 while 96.99% and 97.28% based on ICRP 106. Whereas, the range of mean percentage difference between calculated and measured organ doses derived from ICRP 106 and ICRP 80 for kidney doses were from 17.00% to 40.00% and for urinary bladder dose was 18.46% to 18.75%. CONCLUSIONS: There is a significant difference between calculated dose and measured dose. The use of organ activity estimation based on drawn ROI and the latest version of ICRP 106 dose coefficient should be explored deeper to obtain accurate radiation dose to patients.
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Introduction: Specific mutations in the epidermal growth factor receptor (EGFR) characterize a subgroup of nonsmall cell lung cancer (NSCLC) patients that may be highly responsive to receptor inhibitor therapy. 18F-FDG PET/CT scans can map the glucose metabolism and treatment response of NSCLC. Therefore, we aimed to assess the pattern of metabolic response and outcome of inoperable NSCLC treated with epidermal growth factor receptor (EGFR) inhibitors, using 18F-FDG PET/CT scan. Methods: A retrospective study of inoperable NSCLC patients on EGFR inhibitor treatment that were referred for wholebody18F-FDG PET/CT scans was conducted based on cases scanned from January 2011 to June 2014. Comparison was made among serial attenuation-corrected fused PET/CT images for all study patients throughout the course of their treatment. Comparison based on PERCIST criteria was categorized into 4 levels ie. complete response (CMR), partial response (PMR), stable disease (SMD), progressive metabolic disease (PMD). Results: Overall, there were 5 patients identified, mean age: 57.4 years old +/- 2.9 years; The median survival time from initiation of EGFR inhibitor treatment to death was 17 months. Two patients showed initial partial metabolic response (PMR), two had progressive metabolic disease (PMD) and one had complete metabolic response (CMR) after the initiation of treatment. The patient with initial CMR had relapse and PMD 5 months later. Majority of patients eventually succumbed to their illness. Conclusions: Wholebody18F-FDG PET/CT is able to assess metabolic treatment response of NSCLC towards EGFR inhibitor treatment.
