Assessment of Dose and Lifetime Risk of Exposure Induced Cancer in Adult Common Computed Tomography Scans in Douala-Cameroon

Background: Among medical technologies that use ionizing radiation, CT is currently the radio diagnostic technic that can deliver the highest radiation to the Patient compared with other conventional procedures. In developing countries, the uses and risks of CT have not been well characterized. Objective: To estimate the lifetime attributable risk (LAR) incidence and mortality for cancer for each procedure for adult’s patients who had Computed Tomography examinations in 10 imaging centers in the city of Douala-Cameroon so as to provide a reference data. Materials and Methods: We conducted a cross-sectional study describing radiation dose associated with the 8 most common types of diagnostic CT studies performed on 1287 consecutive adult patients at 10 Douala radiology department. We estimated lifetime attributable risks of cancer by study type from these measured doses. Estimation of LAR for cancer incidence and mortality was based on the effective dose, patient’s sex and age at exposure using the BIER VII preferred models. Results: Mean effective dose from CT scans examinations varied from: 0.30 and 8.81 mSv. The highest doses were observed for lumbar spine CT (8.81 mSv), followed by abdomen-pelvis procedure (6.46 mSv), chest-abdomen-pelvic CT (6.61 mSv), chest CT (3.90 mSv), cervical Spine CT (3.05 mSv), head CT (1.7 mSv) and lower for sinus CT (0.30 mSv). The LAR values of all cancer from patients’ CT scans obtained vary from 67.13 excess per 100,000 (about 1 in 1489) and 0.45 excess per 100,000 (about 1 in 222,222). All cancer risk was high for lumbar spine CT in women 20 years old (67.13 excess deaths in 100,000 scans) followed by chest-abdomen-pelvic CT (50.36 excess deaths in 100,000 scans) and abdomen-pelvic CT (49.22 excess deaths in 100,000 scans) for the same age group. The LAR of incidence and mortality values were higher from female’s patients than males and higher for younger than older patients. Conclusion: This study was set out to estimate the LAR values associated with adult common CT scans procedures. The data indicates, LAR risks related to induced cancer from CT exposures were estimated to be low. This risk can be relatively significant for younger age group compared to older age group. The LAR values obtained will help to better evaluate radiation exposure risk, before ordering a CT scans examinations.

借鉴美国ACRL和SCANS标准刍议高职生信息素养与职业技能的关系

新经济时代,职业种类多样化,职业技能高能化,终身学习普遍化,使职业教育培养成为一种必须的手段,信息素养的高低被学者和职场人普遍认为是辅助职业能力提升的最重要因素之一。为探究学生信息素养与职业技能关系,借鉴美国ACRL和SCANS标准,针对高职学生进行问卷调查,实证研究并分析结果,提出提升大学生信息素养的参考建议。

美国劳工部“SCANS报告”对我国建构新学力观的启迪

学力是借助学科和教材有计划的系统的授受,是以知识技能为核心而形成的种种能力。不同的时代和社会对学力有着不同衡量和判断的标准。目前,在新的教育背景下,学力观的转型是我国教育领域所面临的难题之一。美国劳工部于1991年发表的"SCANS报告"中提出了"五种能力"和"三个基础",对我们构建新的学力观有一定的启迪意义。

地形因素对ScanSAR辐射特性的影响

地形对精确的ScanSAR辐射定标来说是个不容忽视的因素。目前,有关地形因素对条带模式SAR辐射特性的影响已做过大量研究,文中针对ScanSAR模式的特点,研究地形对ScanSAR辐射特性的影响,包括地形对散射面积效应的影响以及地形对scallop ing效应和波束边界现象的影响,并对其进行了定量分析。

ESTIMATION OF DOPPLER CENTROID FREQUENCY IN SPACEBORNE SCANSAR

Doppler centroid frequency is an essential parameter in the imaging processing of the Scanning mode Synthetic Aperture Radar (ScanSAR). Inaccurate Doppler centroid frequency will result in ghost images in imaging result. In this letter, the principle and algorithms of Doppler centroid frequency estimation are introduced. Then the echo data of ScanSAR system is analyzed. Based on the algorithms of energy balancing and correlation Doppler estimator in the estimation of Doppler centroid frequency in strip mode SAR, an improved method for Doppler centroid frequency estimation in ScanSAR is proposed. The method has improved the accuracy of Doppler centroid frequency estimation in ScanSAR by zero padding between burst data. Finally, the proposed method is validated with the processing of ENVIronment SATellite Advanced Synthetic Aperture Radar (ENVISAT ASAR) wide swath raw data.

Multiple helical scans and the reconstruction of over FOV-sized objects in cone-beam CT

In cone-beam computed tomography （CBCT）, there are often cases where the size of the specimen is larger than the field of view （FOV） （referred to as over FOV-sized （OFS））. To acquire the complete projection data for OFS objects, some scan modes have been developed for long objects and short but over-wide objects. However, these modes still cannot meet the requirements for both longitudinally long and transversely wide objects. In this paper, we propose a multiple helical scan mode and a corresponding reconstruction algorithm for both longitudinally long and transversely wide objects. The simulation results show that our model can deal with the problem and that the results are acceptable, while the OFS object is twice as long compared with the FOV in the same latitude.

Efficient Computer Aided Diagnosis System for Hepatic Tumors Using Computed Tomography Scans

One of the leading causes of mortality worldwide is liver cancer.The earlier the detection of hepatic tumors,the lower the mortality rate.This paper introduces a computer-aided diagnosis system to extract hepatic tumors from computed tomography scans and classify them into malignant or benign tumors.Segmenting hepatic tumors from computed tomography scans is considered a challenging task due to the fuzziness in the liver pixel range,intensity values overlap between the liver and neighboring organs,high noise from computed tomography scanner,and large variance in tumors shapes.The proposed method consists of three main stages;liver segmentation using Fast Generalized Fuzzy C-Means,tumor segmentation using dynamic thresholding,and the tumor’s classification into malignant/benign using support vector machines classifier.The performance of the proposed system was evaluated using three liver benchmark datasets,which are MICCAI-Sliver07,LiTS17,and 3Dircadb.The proposed computer adided diagnosis system achieved an average accuracy of 96.75%,sensetivity of 96.38%,specificity of 95.20%and Dice similarity coefficient of 95.13%.

The multi-motion-overlap algorithms for minimizing the time between successive scans of wafer stage

In order to optimize the transitional time during the successive exposure scans for a step-and-scan lithography and improve the productivity in a wafer production process, an investigation of the motion trajectory planning along the scanning direction for wafer stage was carried out. The motions of wafer stage were divided into two respective logical moves （i. e. step-move and scan-move） and the multi-motionoverlap algorithms （MMOA） were presented for optimizing the transitional time between the successive exposure scans. The conventional motion planning method, the Hazelton method and the MMOA were analyzed theoretically and simulated using MATLAB under four different exposure field sizes. The results show that the total time between two successive scans consumed by MMOA is reduced by 4.82%, 2.62%, 3.06% and 3.96%, compared with those of the conventional motion planning method; and reduced by 2.58%, 0.76%, 1.63% and 2.92%, compared with those of the Hazehon method respectively. The theoretical analyses and simulation results illuminate that the MMOA can effectively minimize the transitional step time between successive exposure scans and therefore increase the wafer fabricating productivity.

Dose Optimization in Computer Tomography Pediatric Cranial Scans

Background and Objective: Nowadays, Computer Tomography is one of the best radiological imaging technics which can give right diagnostic information, among the detection of multiphasic adenomas, the detection of cardiac, cerebral and vascular abnormalities. Although these good qualities, this technic is too radiant for the patient. In this paper, we based on the irradiation doses delivered from the current protocols to find a practical method of their optimization during the pediatric cranial scan. Materials and Methods: This work relies on a collection of data from patients in the hospitals, so that analyze them, give the conclusions and, propose an optimal practical method to decrease the irradiation doses. To collect data, we performed a prospective study of seventeen months (from December 2017 to May 2019) carried out simultaneously in three hospitals of the city: The Centre Medical la Cathédrale (H1), the Yaoundé Central Hospital (H2) and the Yaoundé Gyneaco-Obstetric and pediatric hospital (H3). This study included a total of 192 cases of cerebral trauma, of which 11 cases excluded for incomplete information. The dosimetry quality control (CTDIvol) using the PMMA phantoms of 16 cm and 32 cm fulfilled. The scanographic parameters of the patient acquisition protocol were recorded and analyzed. Some of those parameters were modified and entered the CT with the help of a biomedical engineer to reduce the delivered dose. The relationship between CTDIvol and kV is statistically significant (p Results: Among patients, 172 are boys, and the remaining 9 are girls all were in the 0 to 15 age group. CTDIvol values varied from 34.2 mGy to 107.8 mGy and PDLs from 107.8 mGy.cm to 2214.5 mGy.cm in H1. In H2, CTDIvol varied from 5.8 mGy to 44 mGy and PDLs from 91.4 mGy.cm to 665.5 mGy.cm. CTDIvol varied between 9.34 mGy to 92.81 mGy and PDLs from 162.38 mGy.cm to 2713.67 mGy.cm in H3. All values are taken at 75th percentile, with or without contrast injection. Conclusion: The implementation of the optimization of protocols requires the display of the CT parameters to use and to respect during the traumatic brain tests. With displaying and respecting protocol, the CTDIvol decreased by almost 50 per cent.

CT Scans and Delays in Diagnosis of Stroke in Senegal’s Regional Hospitals: A Multicenter Study of 655 Cases

Stroke represents the 2nd cause of mortality and 1st cause of physical disability in the adult population. In Senegal, it represents 30% of hospitalization and 2/3 of the mortality in the department of neurology in the capital city, Dakar. Objective: To specify the types of stroke and to evaluate diagnostic delays in Senegal’s regional hospitals. Materials and Methods: This was a retrospective, cross-sectional, descriptive, multicentric study for 4 years (from 2014 to 2017) including any patient presenting a clinical suspicion with a CT scan confirmation of stroke in one of the 9 regional hospitals in Senegal with a recruitment period of 6 months per hospital. CT scans were performed with a 16 slices machine in 6 hospitals, 4 slices in 2 hospitals and 2 slices in 1 hospital. We studied the types and location of strokes, the associated signs and the time from stroke onset to admission and the time from admission to CT scan. Results: 655 patients were retained including 322 men and 333 women for an M/F ratio of 0.96. The average age was 63 years (range: 7 years, 112 years). High blood pressure was noted in 59.2% of patients and diabetes in 10.7% of patients. Strokes were ischemic in 76% of cases involving the middle cerebral artery in 73% of cases and hemorrhagic in 24%, of which 80.7% were deep localized. A mass effect was noted in 7.5% of cases, an engagement in 6.9% of cases and ventricular hemorrhage in 2.7% of cases. The delay between the onset of the deficit and admission was less than 6 hours in 10.6% of patients. The time between the onset of stroke and admission to hospital was specified in 416 patients (63.5%) of the study population, it was less than 6 hours in 10.6% of patients, between 6 hours and 24 hours for 29.3% and more than 24 hours for 60.1%. Between admission and the CT scan, the time was precise in 459 patients (70%), it was less than 6 hours in 37.9%, between 6 hours and 24 hours in 43.6 % and more than 24 hours in 18.5%. Conclusion: CT is central to the diagnosis of stroke in rural areas. However, there is a significant delay in diagnosis and management.

Stereotactic Radiofrequency Ablation of Trigeminal Ganglion with Intraoperative CT Scans and under General Anesthesia

Introduction: Traditionally radiofrequency ablation of the trigeminal ganglion is performed using fluoroscopy and under heavy sedation. Intra-operative stimulation studies are used in order to confirm the presence of the probe tip in the appropriate division. Unfortunately, in older patients it becomes challenging to transition between heavy sedation (for probe insertion and lesion generation) and light sedation (for stimulation studies). To solve this problem, the authors describe a method in which the procedure was performed under general anesthesia and appropriate needle position was confirmed by intraoperative CT scans. Furthermore, to make the procedure more accurate a stereotactic frame was used. Methods: Eleven procedures were performed on 10 patients from 2012-2015 with a median follow-up of 21 months. The age range of the patients was 33 - 90 years (median of 55), and with a male to female ratio of 6:4. Ablations were accomplished on the 3rd division in five patients, the 2nd division in three patients, and 2nd and 3rd divisions in two patients (one of them underwent bilateral procedures). The procedures were performed under general anesthesia, using a Patil stereotactic frame on the CT table. The center of the foramen ovale was chosen as the target. The probe insertion point was approximately 2.5 cm lateral to the angle of the mouth. To place the probe tip in the 3rd division it was advanced through the foramen ovale into the trigeminal ganglion until its tip was 5 mm anterior to the clival plane. To place it in the 2nd division, it was advanced until it was in the clival plane. The probe had an exposed tip of 8 mm and heating was done at 75?C for 60 seconds. Results: Nine patients are pain-free;one patient, who had atypical facial pain did not benefit from the procedure;and one patient (with bilateral pain) has hyperesthesia on one side. Conclusion: Trigeminal ganglion ablation under general anesthesia is a good option for older patients and for those who cannot tolerate being awakened during the procedure. The stereotactic method enables easy placement of the probe and intraoperative CT scans affords confirmation of accurate probe placement.

Evaluation of eikonic characteristic of skeletal metastasis of primary pulmonary carcinoma with ^(99)Tc^m methylene diphosphonate whole-body bone scans

Objective： The aim of our study was to explore the eikonic characteristic of skeletal metastasis of primary pul- monary carcinoma. Methods： Whole-body bone scans with 99Tcm methylene diphosphonate were performed in 258 patients with pathologically proven pulmonary carcinoma. The rate of skeletal metastasis, distribution of the metastatic lesions and their characteristics were analyzed. Results： Among the total 258 patients, 142 cases developed skeletal metastasis. The overall rate of skeletal metastasis was 55.0%. The metastases located in axial skeleton were 49.6%, appendicular skeleton 36.0%, trunk bones of the axial skeleton 48.4%, and appendicular girdle skeleton 31.4%. Ribs, thoracic vertebrae, ilium and lumbar vertebrae had a higher rate of skeletal metastasis, which were 38.4%, 24.0%, 21.7%, 20.2%, respectively. 1252 le- sions were detected including 406 at the left side of the body, 387 lesions at the middle position and 459 at the right side of the body. There was no significant difference in terms of number of lesions between left side and right side （X2 = 3.3, P = 0.072）. 1224 skeletal metastatic foci （97.8%） were presented as strong radioactive, 26 （2.1%） as mixed lesions, and 2 （0.2%） as low radioactive. According to the shape of lesions, there were 810 punctate lesions （71.5%）, 159 （14.0%） lump form, 108 （9.5%） strip form and 56 （4.9%） lamellar form. The accumulative skeletal metastasis rate was 28.7% for the patients with one to three lesions. The metastasis rate decreased gradually as the number of metastatic lesions increased. Conclusion： Skeletal metastasis is very common in patients with pulmonary carcinoma. Most skeletal metastases are characterized by strong radio- active and earlier punctate form; they often occur in the trunk bones of axial skeleton or appendicular girdles. The distribution of earlier metastases has not obvious regularity, and advanced skeletal metastases are widely and randomly distributed in the body, which are characterized by often concurrently multiple and polymorphous lesions.

Sensitivity of Esophageal Scintigraphy (Milk Scans) in Detecting Gastro-Esophageal Reflux

Gastro-esophageal scintigraphy (milk scan) is an accurate technique for detecting gastro-esophageal reflux that can be performed rapidly with minimal patient discomfort. A retrospective study was performed to find out to how much radionuclide milk scan is sensitive for detecting gastro-esophageal reflux (GER) for 89 patients who subjected to milk scan within Years 2010 to 2013. The study group age is ranging from one month old to four years old. Milk scan was performed using PHILIPS and SEIMENS machine. Tc 99-m sulfur colloid with milk administrated orally or through nasogastric tube to the patient. The highest frequency for milk scan study was in age group of 0 - 6 months old with 77% positive finding. Patients who suffer repeated vomiting represented the highest reason of examination for milk scan (46% of overall cases), while chocking attacks, pulmonary aspiration, and congenital heart disease, were 26%, 16%, 12% respectively of the overall cases. Seventy-nine percent of patients who prepared to be examine using nasogastric tube found with positive finding, 50% of GER patients have abnormal tracer activity in the mid of esophagus;on the other hand, 50% of GER patients divided equally between the lower and upper esophagus. The study show that infants especially in age of 0 - 6 months old and with repeated vomiting symptoms are strongly recommended to milk scan study rather than fluoroscopy to avoid unnecessary dose to the patients.

An Adaptive Algorithm to Detect Port Scans

Detection of port scan is an important component in a network intrusion detection and prevention system. Traditional statistical methods can be easily evaded by stealthy scans and are prone to DoS attacks. This paper presents a new mechanism termed PSD(port scan detection), which is based on TCP packet anomaly evaluation. By learning the port distribution and flags of TCP packets arriving at the protected hosts, PSD can compute the anomaly score of each packet and effectively detect port scans including slow scans and stealthy scans. Experiments show that PSD has high detection accuracy and low detection latency.

Practice patterns and outcomes of equivocal bone scans for patients with castration-resistant prostate cancer: Results from SEARCH

Objective:To review follow-up imaging after equivocal bone scans in men with castration resistant prostate cancer(CRPC)and examine the characteristics of equivocal bone scans that are associated with positive follow-up imaging.Methods:We identified 639 men from five Veterans Affairs Hospitals with a technetium-99m bone scan after CRPC diagnosis,of whom 99(15%)had equivocal scans.Men with equivocal scans were segregated into“high-risk”and“low-risk”subcategories based upon wording in the bone scan report.All follow-up imaging(bone scans,computed tomography[CT],magnetic resonance imaging[MRI],and X-rays)in the 3 months after the equivocal scan were reviewed.Variables were compared between patients with a positive vs.negative follow-up imaging after an equivocal bone scan.Results:Of 99 men with an equivocal bone scan,43(43%)received at least one follow-up imaging test,including 32/82(39%)with low-risk scans and 11/17(65%)with high-risk scans(p=0.052).Of follow-up tests,67%were negative,14%were equivocal,and 19%were positive.Among those who underwent follow-up imaging,3/32(9%)low-risk men had metastases vs.5/11(45%)high-risk men(p=0.015).Conclusion:While 19%of all men who received follow-up imaging had positive follow-up imaging,only 9%of those with a low-risk equivocal bone scan had metastases versus 45%of those with high-risk.These preliminary findings,if confirmed in larger studies,suggest follow-up imaging tests for low-risk equivocal scans can be delayed while high-risk equivocal scans should receive follow-up imaging.

Significance of computed tomography scans in head injury

Background: In view of the growing population and increased vehicle use, traumatic brain injury is becoming the most common and devastating problem especially in young healthy people. It has occupied second place next to cancer as leading cause of death. In this new era of radiology, computed tomography has become the primary modality of choice in the initial assessment of head injury patients as it is widely available, faster and highly accurate in detecting skull fractures and acute intracranial hemorrhage. Aim: It is to demonstrate the importance of ct scanning in the initial treatment planning, follow up and long term management of patients with acute head injury of varying severity. Patients: A retrospective study has been carried out of 100 cases of acute head trauma with positive CT scanning referred to Narayana medical college and hospital, Nellore, India between 30th April 2012 to 1st May 2013 [1 year retrospective study]. Results: The post traumatic intracranial consequences have been collected, reviewed and analyzed, where in 82% of cases males were involved , and most of the injured people belong to the first three decades of life, the main cause being road traffic accident which is growing in incidence in this 21st century. Most of the cases which were studied showed skull fractures, which indicates that there has been significant trauma and in a single case more than one pathology related to cranium has been seen. The most common post traumatic consequences found in the study of adults are contusions, brain edema and intracerebral hematomas, while other sequelae such as subarachnoid hematomas, subdural hematomas and extradural hematomas are encountered less. Diffuse and focal cerebral edema was being the most common pathology following trauma in children. Conclusion: CT scanning is the primary modality of choice in the diagnostic work up of patients with acute head trauma for identifying the various intracranial consequences following head injury especially within 48 hours which helps in the initial assessment, treatment planning, follow up and long term management of patients.

Industrial Equipment Troubleshooting with Imaging Technique Improved Gamma-Ray Absorption Scans

Gamma scanning is one of the most common nuclear techniques on troubleshooting industrial equipments like distillation columns and reactors. With a very simple concept, the technique is easy to implement. Searching for a competitive edge the industry has been long developing solutions to achieve better results. On the last decades, significant development has been done with the advent of new equipments, electronics, portable computers and software. Continuous scanning and wireless detection systems are examples of successful field solutions, while new software aid on reporting and data presentation. However the type and quality of the results itself has not dramatically changed since its beginning. A scan profile is simple to understand, although the process to build it can be very complex as it requires a specific blend of knowledge and abilities. Process engineering, chemical engineering, internal hydraulic project, nuclear engineering and field abilities are pre requisites for of any scan specialist. Correct data gathering, interpretation and reporting are abilities often difficult to match or requires a long time of training. The industry faces a similar difficult on the customer side, as it is always necessary to train end users to understand a report and how to use its best. This paper describes our effort on developing a new approach on the gamma scan test using image reconstruction techniques that would result on a graphic image rather than a XY plot. Direct and easier to understand, a report with graphic images would be also be accessible to a wider audience, not limited to the customers experienced with gamma scan interpretation.

Nonlinear Refraction of Peripheral-Substituted Zinc Phthalocyanines Investigated by Nanosecond and Picose-cond Z Scans

The singlet and triplet excited-state refraction cross-sections of dimethyl sulfoxide (DMSO) solutions of ten zinc phthalocyanine derivatives with mono-or tetra-peripheral substituents at 532 nm were obtained by simultaneous fitting of closed-aperture Z scans with both nanosecond and picosecond pulse widths. Self-focusing of both nanosecond and picosecond laser pulses was observed in all complexes at 532-nm wavelength. The complexes with tetra-substituents at the ?-position exhibit relatively larger refraction cross-sections than the other complexes. The wavelength dependence of the singlet refraction cross-section of a representative complex was observed to be non-monotonic in the range of 470 - 550 nm.

Evaluation of CT Scans Reports in Pancreatic Tumors at Ouagadougou (Burkina Faso)

Background: There are no recommendations for the use of standardised CT reports in oncology in our country. The aim of this study was to evaluate CT reports of pancreatic tumors in the city of Ouagadougou. Materials and Methods: Descriptive, multicenter, cross-sectional study conducted from 1st January 2013 to 31 December 2021. It concerned CT scan reports from five public and private imaging centers in the city of Ouagadougou. During the study period, 41 reports of pancreatic tumors were collected. We evaluated the reports using the standardized model developed by the Society of Abdominal Radiology and the American Pancreatic Association as a reference. Results: CT scan reports were not standardised. The writing style was free. Concerning the lesion, the aspect of the tumor at the pancreatic time was the item with the least information (24.4%). The status of the superior mesenteric artery was mentioned in 17%, the celiac trunk and the portal trunk in 12.2% of cases and 9.7% for the superior mesenteric vein. No report noted the appearance of the common hepatic artery. The status of the lymph nodes, liver and peritoneal cavity was mentioned in all reports. The exact location of the lymph nodes was not specified. The analysis of the reports classified them into two groups: potentially resectable tumours in the absence of secondary locations in 31.7% of cases and locally advanced tumours or presence of metastases in 68.3% of cases. Conclusion: The CT reports were not standardized. The items allowing evaluating the loco-regional extension of the tumor were the least specified. This may suggest the high rate of potentially resectable tumours in our study.

疫情带来了新的环境问题芬林纸板用创新设计来解决--口罩废弃桶荣获ScanStar2021大奖

芬林纸板采用瓦楞制成的创新设计--口罩废弃桶被斯堪的纳维亚包装协会(SPA)授予设计竞赛ScanStar大奖。这个口罩废弃桶采用了轻质耐用的瓦楞纸板,可用来安全方便地收集废弃口罩。芬林纸板与一家包装设计室Futupack以及瓦楞包装厂Capertum共同合作,开发了这一概念。竞赛评委评论道:“这一简单而机智的方案解决了一个新挑战:口罩废弃物。”废弃桶采用瓦楞纸板为原材料,组装简便,即便是组装说明已被印在桶身上。顶盖令这一轻型的包装更为硬挺,如果将顶盖转个向,就可以在垃圾桶满了以后将整个桶封口。良好的印刷也为产品加分。这一垃圾桶设计对行动不便的人士也很友好。