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Pakistan is highly vulnerable to extreme climatic events, such as floods and droughts. This study determines the farmers’ risk perception, risk attitude, adaptation measures and various aspects of vulnerability to climate change (e.g. floods, droughts, heavy rainfalls, pests and disease) at farm level in rural Pakistan. The risk perception and attitude of farm households are crucial factors that influence farm productivity, investment and management decisions at this level. A well-designed questionnaire was used to interview 720 farm households from six districts of the Khyber Pakhtunkhwa province. A binary logit model was used to determine the main factors that affect the choice of adaptation strategies of the farm household. The findings revealed that crop diversification, changing crop varieties, altering the crop calendar, varying the fertilizer used, mulching and farm insurance were the main adaptation strategies followed by farm households. The results of the binary logit model revealed that age, education, farm size, household size, credit accessibility, annual income and the perception on the increase in temperature and decrease in rainfall had significant influence on the selection of the adaption strategies. The findings of this study can provide guidance, policy recommendations and reference for future researchers.

The purpose of this study was to assess quantitatively elongation of mobile targets in cone‐beam CT (CBCT) imaging by measurement and modeling. A mathematical model was derived that predicts the measured lengths of mobile targets and its dependence on target size and motion patterns in CBCT imaging. Three tissue‐equivalent targets of differing sizes were inserted in an artificial thorax phantom to simulate lung lesions. Respiratory motion was mimicked with a mobile phantom that moves in one‐dimension along the superior‐inferior direction at a respiration frequency of 0.24 Hz for eight different amplitudes in the range 0‐40 mm. A mathematical model was derived to quantify the variations in target lengths and its dependence on phantom motion parameters in CBCT. Predictions of the model were verified by measurement of the lengths of mobile targets in CBCT images. The model predicts that target lengths increased linearly with increase in speed and amplitude of phantom motion in CBCT. The measured lengths of mobile targets imaged with CBCT agreed with the calculated lengths within half‐slice thickness spatial resolution. The maximal length of a mobile target was independent of the frequency and phase of motion. Elongation of mobile targets was similar in halffan and full‐fan CBCT for similar motion patterns, as long as the targets remained within the imaging view. Mobile targets elongated linearly with phantom speed and motion amplitude in CBCT imaging. The model introduced in this work assessed quantitatively the variation in target lengths induced by motion, which may be a useful tool to consider elongations of mobile targets in CBCT applications in diagnostic imaging and radiotherapy. PACS number: 87.57.qp

Introduction We aim to quantify the variations in the gross tumour volume (GTV) during a course of stereotactic body radiotherapy (SBRT) and determine its impact on dosimetric coverage of the GTV. Methods The GTVs and dose coverage for 14 patients with 16 primary non-small-cell lung tumours treated with SBRT were investigated. Initial GTVs were calculated from treatment planning CT scans. The prescribed doses ranged from 48 to 60 Gy in three to five fractions. Before each treatment, patients underwent a CBCT scan. For each CBCT scan, the GTV and the dose received by the GTV were determined and followed during the course of therapy. Results There was considerable variation in the measured GTVs during the course of therapy. Increases of up to 63.3% of volume measured by initial CBCT were detected during the first few fractions, after which GTV tended to decrease. Dose coverage (V95) for any given fraction deviated no more than 5% from optimised coverage obtained in the initial treatment plan. In the long term, all patients with follow-up scans demonstrated tumour shrinkage with no radiographic evidence of tumour recurrence. Conclusion GTV, as evaluated in this study, demonstrates an initial increase in volume followed by a subsequent decrease. This volume change needs to be considered in the design of treatment plans and assignment of treatment margins.

This study contributes to the extant literature on the nexus among energy consumption, agriculture, capital and economic growth in Pakistan. We use time series data from 1971 to 2014 and employ the Non-linear Autoregressive Distributed Lag (NARDL) model. The NARDL testing results affirms asymmetric co-integration among the variables. Asymmetric causality is noted between positive shocks in energy consumption and economic growth running from energy consumption to economic growth. A feedback effect is found between agriculture and economic growth for positive shocks. A unidirectional nexus is noted between capital and economic growth for both positive and negative shocks. Similarly, the results of a Granger causality test indicate symmetric causality between energy consumption, agriculture, capital and economic growth. This research suggests that policymakers should revisit their policies regarding agriculture and energy sectors by attracting foreigner investors to build new hydropower dams to both affirm the availability of energy to the industrial sector and control the scarcity of water.

Background: Acute cholecystitis is one of the hepatopancreatobiliary emergencies. With more and more experience in the laparoscopic cholecystectomy studies are being carried out evaluating the effectiveness and feasibility of early laparoscopic cholecystectomy in acute cholecystitis.Methods: Fifty patients presenting with acute cholecystitis were included in this study and randomized using chit in the box method into two groups- early group and delayed group.Results: Mean duration of surgery in the early group is 42.28±5.99 mins and in the delayed group is 39.12±5.55 mins (p=0.06). Gallbladder perforation was reported in 4 patients (16%) in early group and in 2 patients (8%) in delayed group (p=0.67). Gall stone spillage was reported in 3 patients (12%) in early group and in 2 patients (8%) in delayed group (p=1.00). At 6th hr mean VAS (visual analogue scale) score in the early group was 4.0±0.41 and in the delayed group it was 3.6±0.58 (p=0.01). At 12th hr mean VAS score in the early group was 3.4±0.51 and in the delayed group it was 3.3±0.48 (p=0.39). Mean duration of postoperative stay was 2.24±0.60 days in early group and in the delayed group it was 2.08±0.57 days (p=0.34).Conclusions: It has been found that early laparoscopic cholecystectomy is safe and feasible in the setting of acute cholecystitis with added advantage of shorter total hospital stay.

This paper presents the design of dual-band frequency reconfigurable fork shape planar dipole in the industrial, scientific and medical (ISM) band (2.4 and 5.2 GHz). The proposed antenna can be used for wireless local area network (WLAN) applications. Antenna operates in dual-band as well as single-band mode depending on switching combination. The proposed antenna gives bandwidth of 12.5% and 6.7% for 2.4 GHz and 5.2 GHz, respectively, in dual-band mode while 15.5% for 2.4 GHz in single-band mode. The performance of the antenna is analysed with a ground-free substrate and traditional perfect electric conductor (PEC) ground plane. The same antenna is mounted on a dual-band slotted mushroom-type electromagnetic bandgap (EBG) surface which improves the return loss of the antenna in both bands by –25 dB w. r. t. the PEC-based dipole antenna. The proposed antenna can be used in WLAN applications. The simulations were carried out in SEMCAD and CST MWS.

The aim of this thesis is to explore new simpler and efficient routes for the preparation of surface organometallic complexes (SOMC) for the transformation of small organic molecules to valuable products. The key element in this new route relies on surface alkylation of various halogenated surface coordination complexes or organometallic fragments (SOMF).

Sağlık kuruluşları, kalite iyileştirme amacıyla dünyanın birçok bölgesinde hastanelerde Toplam Kalite Yönetiminin (TKY) uygulanmasını sağlamaya çalışmaktadır. Sağlık çalışanlarının Toplam Kalite Yönetimi konusundaki algılarının değerlendirilmesi, Toplam Kalite Yönetimi sürecinin dizaynı, uygulanması ve değerlendirilmesine yardımcı olabilir. Bu araştırmanın amacı, Türkiye-Isparta Devlet Hastanesi ve Irak-Samarra Devlet hastanelerinde çalışan sağlık personelinin İnsan Kaynakları Açısından Toplam Kalite Yönetimine ilişkin algılarını değerlendirmektir. Bu bilginin hastanelerdeki Toplam Kalite Yönetim sürecinin dizaynı, uygulanması ve yapılacak değişiklikler için faydalı olması beklenmektedir. Araştırmada anket yöntemi ile elde edilen veriler güvenirlilik testine tabi tutularak verilen cevapların güvenirliliği test edilmiştir. Anket iki bölümden oluşmaktadır. Birinci bölüm, çalışmaya katılanların demografik bilgilerini içermekte, ikinci bölüm ise Toplam Kalite Yönetimi'nin planlanması, uygulanması ve başarıya ulaşması ile ilgili 25 ifadeden oluşmaktadır. Aynı zamanda frekans dağılımlarında görüleceği gibi değişkenlere verilen cevaplar da yüksek ortalamalara sahiptir. Ancak Isparta Devlet Hastanesi çalışanlarının her soruda daha yüksek ortalamalara sahip olduğu görülmüştür.Anahtar kelimeler: İnsan Kaynakları Yönetimi, Toplam Kalite Yönetimi, Sağlık Kurumları İşletmeleri Healthcare organizations in many parts of the world intend to implement the Toplam Quality Management for purposes of enhancing the quality they offer at their hospitals. Developing positive understanding towards Toplam Quality Management among healthcare professionals might help the design, implementation and evaluation of the Toplam Quality Management. The objective of this study is to evaluate the perceptions of healthcare professionals working at Isparta, Turkey Public Hospital and Samarra, Iraq Public Hospital towards Toplam Quality Management in terms of Human Resources. The outcomes of the study are expected to help design and implementation of management process as well as possible modifications improve. The reliability of the data obtained via interview method has been tested through reliability tests. The interview involves two parts. First part comprises the demographic info of those who have taken part in the interview while second part involves 25 statements on planning, implementation and achievement of Toplam Quality Management. The responses to variables hold quite high averages as can be inferred from frequency variances. However, it has been found that professionals at Isparta Public Hospital displayed higher averages in each question.Keywords: Human Resources Management, Total Quality Management, Helath Care Organizations 136

This study focuses on L2 learners of English in Swedish upper secondary schools and their ability to comprehend and use connectors in a multiple-choice cloze procedure. Connectors are used in text to signal the text structure and make explicit the relation between text segments. A study by Geva (1992) suggests that with an increased proficiency, learners also improve their ability to comprehend text relations and the use of connectors. The present study applies the suggestions of Geva’s results in a Swedish context. English in Swedish upper secondary schools, is taught at three levels (designated English 5, 6, 7) with increasing difficulty and proficiency level requirements. This study tests the ability to comprehend the context and use the correct connector on pupils in the two mandatory courses (English 5 & 6). Similar to previous studies, the aim is to investigate the relationship between levels of English and the ability to use connectors. This empirical survey investigates the English 5 & 6 pupils’ success in applying the appropriate connector in relation to the level of English they are placed in, in order to analyze whether there is any perceived development, as is presupposed by the English curriculum. Furthermore, the study also aims to analyze what type of connectors the pupils excel at or struggle with and any factors that might affect pupils’ performance. The test consisted of three categories: adversative (6 questions), additive (5 questions), and causal connectors (4 questions), a total of 15 questions, with one point being awarded for each correct response. The results of the two groups were similar and a subsequent t-test revealed that there was no statistical significance between the two groups in any of the categories. This suggests that in the sample which was tested there is no proficiency increase in terms of connectors and comprehending inter-/intrasentential relationships. Furthermore, the results indicate that the pupils are more likely to correctly select the appropriate adversative and causal connectors, but struggled in selecting the additive connectors. Keywords: connectors, comprehension, intrasentential & intersentential relationships, teaching, coherence, cohesion

The purpose of this study was to evaluate the impact of daily setup error and interfraction organ motion on the overall dosimetric radiation treatment plans. Twelve patients undergoing definitive intensity-modulated radiation therapy (IMRT) treatments for prostate cancer were evaluated in this institutional review board-approved study. Each patient had fiducial markers placed into the prostate gland before treatment planning computed tomography scan. IMRT plans were generated using the Eclipse treatment planning system. Each patient was treated to a dose of 8100 cGy given in 45 fractions. In this study, we retrospectively created a plan for each treatment day that had a shift available. To calculate the dose, the patient would have received under this plan, we mathematically "negated" the shift by moving the isocenter in the exact opposite direction of the shift. The individualized daily plans were combined to generate an overall plan sum. The dose distributions from these plans were compared with the treatment plans that were used to treat the patients. Three-hundred ninety daily shifts were negated and their corresponding plans evaluated. The mean isocenter shift based on the location of the fiducial markers was 3.3 ± 6.5 mm to the right, 1.6 ± 5.1 mm posteriorly, and 1.0 ± 5.0 mm along the caudal direction. The mean D95 doses for the prostate gland when setup error was corrected and uncorrected were 8228 and 7844 cGy (p0.002), respectively, and for the planning target volume (PTV8100) was 8089 and 7303 cGy (p0.001), respectively. The mean V95 values when patient setup was corrected and uncorrected were 99.9% and 87.3%, respectively, for the PTV8100 volume (p0.0001). At an individual patient level, the difference in the D95 value for the prostate volume could be1200 cGy and for the PTV8100 could approach almost 2000 cGy when comparing corrected against uncorrected plans. There was no statistically significant difference in the D35 parameter for the surrounding normal tissue except for the dose received by the penile bulb and the right hip. Our dosimetric evaluation suggests significant underdosing with inaccurate target localization and emphasizes the importance of accurate patient setup and target localization. Further studies are needed to evaluate the impact of intrafraction organ motion, rotation, and deformation on doses delivered to target volumes.

critical issues that are serving as constraints in wireless communication particularly in mobile communication are bandwidth, storage memory and power. The speech transmission in wireless networks is associated with the reduction of extra information present in signal in such a way to preserve the quality and intelligibility of speech. To remove the redundancy and transmit the speech with acceptable quality, speech compression algorithms are deployed. Because of this reason the speech coding is and will be the most important research issue. This paper addresses the implementation of CELP coder having low computational complexity with acceptable speech quality and preserves the intelligibility. The coder is assessed in terms of quality for different kinds of speakers using PESQ, PSNR,Frequency Weighted SNRseg, and SNRseg.

This paper presents a comparative study of the performance of a 2.4GHz microstrip patch antenna, using various metamaterial surfaces, each working as a ground plane for the proposed antenna. A 1.6 mm thicker Rogers RT/ Duroid 5880 is used as a substrate material in the design of the antenna. The relative permittivity of the substrate is 2.2. The conventional patch antenna is properly matched to 50 ohms, using an inset-feed mechanism. The gain of the 2.4 GHz patch antenna backed by a conventional ground plane is 7.21dBi. The antenna is then backed by three different types of metamaterial surfaces, Frequency Selective Surface (FSS), Electromagnetic Band Gap (EBG) surface and Artificial Magnetic Conductor Surface (AMC) and their performances are compared and quantified in terms of gain. It is found that the AMC based patch antenna gives the highest gain (9.01dBi) among the used surfaces. It is also found that the surface waves are suppressed relatively more by the FSS ground plane. The artificial surfaces improve the efficiency of the conventional patch antenna due to their high-impedance characteristics, which helps in reducing the losses with in the substrate material. Simulations are performed in High Frequency Structure Simulator (HFSS).

In this paper, we design and analyze a dual-band rectangular microstrip patch antenna with defected ground plane for 2.5 GHz and 3.5 GHz communications. The design concept is to have two slots etched out from the ground plane of a microstrip patch antenna designed for 2.5 GHz operation to enable second frequency band (3.5 GHz) operation. The positions of etched slots are determined using parametric analysis to meet the objectives of large impedance bandwidth and high gains in the desired bands and mismatching in the undesired bands. The proposed antenna provides wide impedance bandwidths of 13.56% (2.3-2.7 GHz) and 10.36% (3.3-3.7 GHz) at center frequencies of 2.5 GHz and 3.5 GHz, respectively. The gains in E-Plane are 6.7 dB and 5.1 dB, and the gains in H-Plane are 6.5 dB and 4.88 dB, for 2.5 GHz and 3.5 GHz, respectively. The proposed dual-band antenna shows monopole-like radiation patterns with higher gains as compared to monopole antennas.

Two recently introduced GafChromic film models, HS and XR-T, have been developed as more sensitive and uniform alternatives to GafChromic MD-55-2 film. The HS model has been specifically designed for measurement of absorbed dose in high-energy photon beams (above 1 MeV), while the XR-T model has been introduced for dose measurements of low energy (0.1 MeV) photons. The goal of this study is to compare the sensitometric curves and estimated dosimetric uncertainties associated with seven different GafChromic film dosimetry systems for the two new film models. The densitometers tested are: LKB Pharmacia UltroScan XL, Molecular Dynamics Personal Densitometer, Nuclear Associates Radiochromic Densitometer Model 37-443, Photoelectron Corporation CMR-604, Laser Pro 16, Vidar VXR-16, and AGFA Arcus II document scanner. Pieces of film were exposed to different doses in a dose range from 0.5 to 50 Gy using 6 MV photon beam. Functional forms for dose vs net optical density have been determined for each of the GafChromic film-dosimetry systems used in this comparison. Two sources of uncertainties in dose measurements, governed by the experimental measurement and calibration curve fit procedure, have been compared for the densitometers used. Among the densitometers tested, it is found that for the HS film type the uncertainty caused by the experimental measurement varies from 1% to 3% while the calibration fit uncertainty ranges from 2% to 4% for doses above 5 Gy. Corresponding uncertainties for XR-T film model are somewhat higher and range from 1% to 5% for experimental and from 2% to 7% for the fit uncertainty estimates. Notwithstanding the significant variations in sensitivity, the studied densitometers exhibit very similar precision for GafChromic film based dose measurements above 5 Gy.

Purpose: To investigate quantitatively the accuracy of dose distributions for the Ir-192 high-dose-rate (HDR) brachytherapy source calculated by the Brachytherapy-Planning system (BPS) and measured using a multiple-array-diode-detector in a heterogeneous medium. Methods: A two-dimensional diode-array-detector system (MapCheck2) was scanned with a catheter and the CT-images were loaded into the Varian-Brachytherapy-Planning which uses TG-43-formalism for dose calculation. Treatment plans were calculated for different combinations of one dwell-position and varying irradiation times and different-dwell positions and fixed irradiation time with the source placed 12mm from the diode-array plane. The calculated dose distributions were compared to the measured doses with MapCheck2 delivered by an Ir-192-source from a Nucletron-Microselectron-V2-remote-after-loader. The linearity of MapCheck2 was tested for a range of dwell-times (2–600 seconds). The angular effect was tested with 30 seconds irradiation delivered to the central-diode and then moving the source away in increments of 10mm. Results: Large differences were found between calculated and measured dose distributions. These differences are mainly due to absence of heterogeneity in the dose calculation and diode-artifacts in the measurements. The dose differences between measured and calculated due to heterogeneity ranged from 5%–12% depending on the position of the source relative to the diodes in MapCheck2 and different heterogeneities in the beam path. The linearity test of the diode-detector showed 3.98%, 2.61%, and 2.27% over-response at short irradiation times of 2, 5, and 10 seconds, respectively, and within 2% for 20 to 600 seconds (p-value=0.05) which depends strongly on MapCheck2 noise. The angular dependency was more pronounced at acute angles ranging up to 34% at 5.7 degrees. Conclusion: Large deviations between measured and calculated dose distributions for HDR-brachytherapy with Ir-192 may be improved when considering medium heterogeneity and dose-artifact of the diodes. This study demonstrates that multiple-array-diode-detectors provide practical and accurate dosimeter to verify doses delivered from the brachytherapy Ir-192-source.

A nanocatalyst of CaO supported by Fe 3 O 4 magnetic particles was prepared by a chemical precipitation method. It was characterized by various techniques including X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM); Fourier transforms infrared spectroscopy (FTIR), and Hammett indicator. It has been found that the catalyst consists of CaO and Fe 3 O 4 accompanied by CaFe 2 O 4 . This composite catalyst was used for the catalytic transesterification of palm seed oil. The results revealed that the highest biodiesel yields for palm seed oil of 69.7% can be obtained under the conditions of (65 °C reaction temperature, 300 min reaction time, 20 methanol/oil molar ratio, and 10 wt.% of CaO/Fe 3 O 4 catalyst loading). The physicochemical properties of the biodiesel produced from palm seed oil were further studied and compared with the ASTM and the EN biodiesel specifications. The results showed that the properties of the biodiesel produced comply with the international standard specifications. Copyright © 2017 BCREC Group. All rights reserved Received: 25 th January 2017; Revised: 11 st July 2017; Accepted: 12 nd July 2017 ; Available online: 27 th October 2017; Published regularly : December 2017 How to Cite: Ali, M.A., Al-Hydary, I.A., Al-Hattab, T.A. (2017). Nano-Magnetic Catalyst CaO-Fe 3 O 4 for Biodiesel Production from Date Palm Seed Oil. Bulletin of Chemical Reaction Engineering & Catalysis , 12 (3): 460-468 (doi:10.9767/bcrec.12.3.923.460-468)

Since the early 1970s a new stream of positive accounting research started to overwhelm the field. It is the idea of predicting managers’ behaviour based on specific facts. A part of this research stream examines the linkages between firmspecific characteristics and accounting activities within firms. This paper aims to provide a literature review of this particular body of research. This review is concerned with collecting the main idea and theories behind the proposed effect for each characteristic. What distinguishes this paper is that it is provide future researchers with an intellectual collection of different ideas and theories which make a complete frame for advanced research. Firm characterises are extensively used in both finance and accounting research. However, only the characteristics that appear most frequently in the accounting literature are considered here. The author tried to be extensive in withdrawing ideas and theory but this does not mean that all extent studies are covered

Purpose To investigate variations in mobile target length induced by sinusoidal motion in helical (HCT) and axial CT (ACT) imaging. A mathematical model was derived that predicts the measured broadening of the apparent lengths of mobile targets and its dependence on motion parameters, target size, and imaging couch speed in CT images. Materials and methods Three mobile targets of differing lengths and sizes were constructed of tissue-equivalent gel material and embedded into artificial lung phantom. Respiratory motion was mimicked with a mobile phantom that moves in one-dimension along the superior-inferior direction with sinusoidal motion patterns. A mathematical model was derived to predict quantitatively the variations of apparent lengths for mobile targets and its dependence on phantom and imaging couch motion parameters in HCT and ACT. The model predictions were verified by length measurements of the mobile phantom targets that were imaged with the different motion patterns using CT imaging. Results The measured lengths of mobile targets enlarged or shrunk depending on the phantom motion parameters that include phantom speed, amplitude, frequency, phase and speed of the imaging couch. The target length variations were significant where some targets doubled lengths or shrunk to less than half of their actual length. The apparent lengths of mobile targets decreased if the target was moving in the same direction as the imaging couch motion and increased if the mobile target was moving opposed to imaging couch in both HCT and ACT. The model predicts well the variations in the mobile target apparent lengths and their dependence on the motion parameters. Conclusion The measured and model variations of apparent lengths of mobile targets are considerable and may affect the accuracy of tumor volumes obtained from HCT and ACT. This mathematical model provides a method to quantitatively assess the length variations of mobile targets and their dependence on motion parameters of the phantom and imaging system which may have potential applications in the fields of diagnostic imaging and radiotherapy.

Neurobehavioral symptoms are not uncommon after a traumatic brain injury. However, psychiatric syndromes per se have rarely been studied in patients with such an injury. The purpose of this study was to evaluate the type and extent of psychiatric syndromes in patients with traumatic brain injury.One hundred ninety-six hospitalized adults were studied 1 year after a traumatic brain injury with the use of a two-stage psychiatric diagnostic procedure. Psychiatric diagnoses were made according to ICD-10 criteria on the basis of data from the Schedules for Clinical Assessment in Neuropsychiatry interview.Of 164 patients interviewed, 30 (18.3%) had an ICD-10 diagnosis of a psychiatric illness. Among the 120 patients who were 18-64 years old, 21.7% had a psychiatric illness, compared with 16.4% in a study of the general population. A depressive illness was present in 13.9% of the traumatic brain injury patients, compared with 2.1% of the general population, and panic disorder was present in 9.0%, compared with 0.8% of the general population.In comparison with the general population, a higher proportion of adult patients had developed psychiatric illnesses 1 year after a traumatic brain injury; the rates of depressive episode and panic disorder were significantly higher in the study group. A history of psychiatric illness, an unfavorable global outcome according to the Glasgow Outcome Scale, a lower score on the Mini-Mental State examination, and fewer years of formal education seemed to be important risk factors in the development of a psychiatric illness. Compensation claims, however, were not associated with the rate of psychiatric illness.

Purpose: To evaluate quantitatively dose distributions from helical, axial and cone-beam CT clinical imaging techniques by measurement using a two-dimensional (2D) diode-array detector. Methods: 2D-dose distributions from selected clinical protocols used for axial, helical and cone-beam CT imaging were measured using a diode-array detector (MapCheck2). The MapCheck2 is composed from solid state diode detectors that are arranged in horizontal and vertical lines with a spacing of 10 mm. A GE-Light-Speed CT-simulator was used to acquire axial and helical CT images and a kV on-board-imager integrated with a Varian TrueBeam-STx machine was used to acquire cone-beam CT (CBCT) images. Results: The dose distributions from axial, helical and cone-beam CT were non-uniform over the region-of-interest with strong spatial and angular dependence. In axial CT, a large dose gradient was measured that decreased from lateral sides to the middle of the phantom due to large superficial dose at the side of the phantom in comparison with larger beam attenuation at the center. The dose decreased at the superior and inferior regions in comparison to the center of the phantom in axial CT. An asymmetry was found between the right-left or superior-inferior sides of the phantom which possibly to angular dependence in the dosemore » distributions. The dose level and distribution varied from one imaging technique into another. For the pelvis technique, axial CT deposited a mean dose of 3.67 cGy, helical CT deposited a mean dose of 1.59 cGy, and CBCT deposited a mean dose of 1.62 cGy. Conclusions: MapCheck2 provides a robust tool to measure directly 2D-dose distributions for CT imaging with high spatial resolution detectors in comparison with ionization chamber that provides a single point measurement or an average dose to the phantom. The dose distributions measured with MapCheck2 consider medium heterogeneity and can represent specific patient dose.« less

Günümüzde insanın en temel haklarından biride ifade özgürlüğüdür. İfade özgürlüğü temel hak ve özgürlükler arasında önemli bir konuma sahiptir. Çünkü insanlar içindeki düşüncelerini ancak ifade ederek dışa vurabilirler. Kişilerin duygu ve düşüncelerini serbest bir şekilde dışa vurabilmeleri için demokratik bir rejimin olması şarttır. Çünkü demokrasi düşünce ve düşünceyi açıklama özgürlüğünün vazgeçilmez bir öğesidir. Demokrasinin olmadığı yerlerde ifade özgürlüğünden bahsetmek mümkün değildir.Bu çalışmada ifade özgürlüğünün kavramsal ve hukuksal boyutları ele alınacaktır.Ayrıca, ifade özgürlüğünün uluslararası sözleşmelerdeki düzenlenişi ve korunmasından bahsedilecektir. Özellikle de Avrupa İnsan Hakları Sözleşmesi Çerçevesinde ve Avrupa İnsan Hakları Mahkemesi kararlarında ifade özgürlüğünün yer alması değerlendirilecektir. Ayrıca ifade özgürlüğünün sınırlamaları konusunda Türk Hukukundaki gelişmeler de incelenecektir. Today, one of the mostbasicrights of human is freedomexpression. Expressionfreedom of has a significantimportancebetweenbasicrightsandfreedoms as humans can onlyshow their thoughtsbyexpressingfreely. So as to Express thoughtsfreely, theremust be democracy as it is an indispensiblefactor of thoughtand its expression. Forplaceswherethere is nodemocracy, it is impossibletomention freedom of expression. Theaspect of conceptualand legal of expressionfreedom is goingto be approached in thisstudy. Also, configuration of freedom of expressionanditsprotection in international documents is goingto be mentioned. Especially, placing of expressionrightwhich is at decision of European Human Right Court andEuropean Human Right Agreement is goingto be evaluated. Also, theaspect of limitingtheexpression freedom of in the development Turkishlaw is goingto be examined. 185

With increasing popularity and complexity of intensity-modulated radiation therapy (IMRT) delivery modalities including regular and arc therapies, there is a growing challenge for validating the accuracy of dose distributions. Gafchromic films have superior characteristics for dose verification over other conventional dosimeters. In order to optimize the use of Gafchromic films in clinical IMRT quality assurance procedures, the scanning parameters of EBT and EBT2 films with a flatbed scanner were investigated. The effects of several parameters including scanning position, orientation, uniformity, film sensitivity and optical density (OD) growth after irradiation were quantified. The profiles of the EBT and EBT2 films had a noise level of 0.6% and 0.7%, respectively. Considerable orientation dependence was observed and the scanner value difference between landscape and portrait modes were about 12% and 10% for EBT and EBT2 films, respectively. The highest response sensitivity was observed using digitized red color images of the EBT2 film scanned with landscape mode. The total system non-uniformity composed of contributions from the film and the scanner was less than 1.7%. OD variations showed that EBT gray scale grew slower, however, reached higher growth values of 15% when compared with EBT2 gray scale which grew 12% after a long time (480 hours) post-irradiation. The EBT film using the red color channel showed the minimal growth where OD increased up to 3% within 3 days after irradiation, and took one week to stabilize.

Purpose: To compare the impact of MLC width on the dose conformity, doses received by the normal brain tissue, and other critical structures for single isocenter (SI) and multiple isocenter (MI) stereotactic IMRT (SRT) treatments for patients with at least four brain tumors. Methods: Six patients (three with seven and three with four lesions) planned in BrainLab iPlan were evaluated using Varian HD MLC (2.5mm leaf-width) and Millennium-120 MLC (5mm leaf-width). Prescribed doses in all plans were 25 Gy delivered in five fractions normalized to 98% dose covering 98% of the target volume. Results: All plans were judged clinically acceptable. The average Paddick conformity index for 2.5mm vs 5mm SI and MI plans were (0.48±0.22 vs. 0.38±0.21, p

Purpose: To evaluate the performance of a two-dimensional (2D) array-diode- detector for geometric and dosimetric quality assurance (QA) tests of high-dose-rate (HDR) brachytherapy with an Ir-192-source. Methods: A phantom setup was designed that encapsulated a two-dimensional (2D) array-diode-detector (MapCheck2) and a catheter for the HDR brachytherapy Ir-192 source. This setup was used to perform both geometric and dosimetric quality assurance for the HDR-Ir192 source. The geometric tests included: (a) measurement of the position of the source and (b) spacing between different dwell positions. The dosimteric tests include: (a) linearity of output with time, (b) end effect and (c) relative dose verification. The 2D-dose distribution measured with MapCheck2 was used to perform the previous tests. The results of MapCheck2 were compared with the corresponding quality assurance testes performed with Gafchromic-film and well-ionization-chamber. Results: The position of the source and the spacing between different dwell-positions were reproducible within 1 mm accuracy by measuring the position of maximal dose using MapCheck2 in contrast to the film which showed a blurred image of the dwell positions due to limited film sensitivity to irradiation. The linearity of the dose with dwell times measured from MapCheck2 was superior to the linearity measured with ionization chamber due to higher signal-to-noise ratio of the diode readings. MapCheck2 provided more accurate measurement of the end effect with uncertainty < 1.5% in comparison with the ionization chamber uncertainty of 3%. Although MapCheck2 did not provide absolute calibration dosimeter for the activity of the source, it provided accurate tool for relative dose verification in HDR-brachytherapy. Conclusion: The 2D-array-diode-detector provides a practical, compact and accurate tool to perform quality assurance for HDR-brachytherapy with an Ir-192 source. The diodes in MapCheck2 have high radiation sensitivity and linearity that is superior to Gafchromic-films and ionization chamber used for geometric and dosimetric QA in HDR-brachytherapy, respectively.

Purpose: To quantitatively investigate the surface dose deposited in patients imaged with a kV on-board-imager mounted on a radiotherapy machine using different clinical imaging techniques and filters. Methods: A high sensitivity photon diode is used to measure the surface dose on central-axis and at an off-axis-point which is mounted on the top of a phantom setup. The dose is measured for different imaging techniques that include: AP-Pelvis, AP-Head, AP-Abdomen, AP-Thorax, and Extremity. The dose measurements from these imaging techniques are combined with various filtering techniques that include: no-filter (open-field), half-fan bowtie (HF), full-fan bowtie (FF) and Cu-plate filters. The relative surface dose for different imaging and filtering techniques is evaluated quantiatively by the ratio of the dose relative to the Cu-plate filter. Results: The lowest surface dose is deposited with the Cu-plate filter. The highest surface dose deposited results from open fields without filter and it is nearly a factor of 8–30 larger than the corresponding imaging technique with the Cu-plate filter. The AP-Abdomen technique delivers the largest surface dose that is nearly 2.7 times larger than the AP-Head technique. The smallest surface dose is obtained from the Extremity imaging technique. Imaging with bowtie filters decreases the surface dose by nearly 33% in comparison with the open field. The surface doses deposited with the HF or FF-bowtie filters are within few percentages. Image-quality of the radiographic images obtained from the different filtering techniques is similar because the Cu-plate eliminates low-energy photons. The HF- and FF-bowtie filters generate intensity-gradients in the radiographs which affects image-quality in the different imaging technique. Conclusion: Surface dose from kV-imaging decreases significantly with the Cu-plate and bowtie-filters compared to imaging without filters using open-field beams. The use of Cu-plate filter does not affect image-quality and may be used as the default in the different imaging techniques.

Purpose: To investigate quantitatively positioning and dosimetric uncertainties due to 4D-CT intra-phase motion in the internal-target-volume (ITV) associated with radiation therapy using respiratory-gating for patients setup with image-guidance-radiation-therapy (IGRT) using free-breathing or average-phase CT-images. Methods: A lung phantom with an embedded tissue-equivalent target is imaged with CT while it is stationary and moving. Four-sets of structures are outlined: (a) the actual target on CT-images of the stationary-target, (b) ITV on CT-images for the free-moving phantom, (c) ITV's from the ten different phases (10–100%) and (d) ITV on the CT-images generated from combining 3 phases: 40%–50%–60%. The variations in volume, length and center-position of the ITV's and their effects on dosimetry during dose delivery for patients setup with image-guidance are investigated. Results: Intra-phase motion due to breathing affects the volume, center position and length of the ITVs from different respiratory-phases. The ITV's vary by about 10% from one phase to another. The largest ITV is measured on the free breathing CT images and the smallest is on the stationary CT-images. The ITV lengths vary by about 4mm where it may shrink or elongated depending on the motion-phase. The center position of the ITV varies between the different motion-phases which shifts upto 10mm from the stationary-position which is nearly equal to motion-amplitude. This causes systematic shifts during dose delivery with beam gating using certain phases (40%–50%–60%) for patients setup with IGRT using free-breathing or average-phase CT-images. The dose coverage of the ITV depends on the margins used for treatment-planning-volume where margins larger than the motion-amplitudes are needed to ensure dose coverage of the ITV. Conclusion: Volume, length, and center position of the ITV's change between the different motion phases. Large systematic shifts are induced by respiratory-gating with ITVs on certain phases when patients are setup with IGRT using free-breathing or average-phase CT-images.

To compare the doses calculated using the BrainLAB pencil beam (PB) and Monte Carlo (MC) algorithms for tumors located in various sites including the lung and evaluate quality assurance procedures required for the verification of the accuracy of dose calculation. The dose-calculation accuracy of PB and MC was also assessed quantitatively with measurement using ionization chamber and Gafchromic films placed in solid water and heterogeneous phantoms. The dose was calculated using PB convolution and MC algorithms in the iPlan treatment planning system from BrainLAB. The dose calculation was performed on the patient's computed tomography images with lesions in various treatment sites including 5 lungs, 5 prostates, 4 brains, 2 head and necks, and 2 paraspinal tissues. A combination of conventional, conformal, and intensity-modulated radiation therapy plans was used in dose calculation. The leaf sequence from intensity-modulated radiation therapy plans or beam shapes from conformal plans and monitor units and other planning parameters calculated by the PB were identical for calculating dose with MC. Heterogeneity correction was considered in both PB and MC dose calculations. Dose-volume parameters such as V95 (volume covered by 95% of prescription dose), dose distributions, and gamma analysis were used to evaluate the calculated dose by PB and MC. The measured doses by ionization chamber and EBT GAFCHROMIC film in solid water and heterogeneous phantoms were used to quantitatively asses the accuracy of dose calculated by PB and MC. The dose-volume histograms and dose distributions calculated by PB and MC in the brain, prostate, paraspinal, and head and neck were in good agreement with one another (within 5%) and provided acceptable planning target volume coverage. However, dose distributions of the patients with lung cancer had large discrepancies. For a plan optimized with PB, the dose coverage was shown as clinically acceptable, whereas in reality, the MC showed a systematic lack of dose coverage. The dose calculated by PB for lung tumors was overestimated by up to 40%. An interesting feature that was observed is that despite large discrepancies in dose-volume histogram coverage of the planning target volume between PB and MC, the point doses at the isocenter (center of the lesions) calculated by both algorithms were within 7% even for lung cases. The dose distributions measured with EBT GAFCHROMIC films in heterogeneous phantoms showed large discrepancies of nearly 15% lower than PB at interfaces between heterogeneous media, where these lower doses measured by the film were in agreement with those by MC. The doses (V95) calculated by MC and PB agreed within 5% for treatment sites with small tissue heterogeneities such as the prostate, brain, head and neck, and paraspinal tumors. Considerable discrepancies, up to 40%, were observed in the dose-volume coverage between MC and PB in lung tumors, which may affect clinical outcomes. The discrepancies between MC and PB increased for 15MV compared with 6MV indicating the importance of implementation of accurate clinical treatment planning such as MC. The comparison of point doses is not representative of the discrepancies in dose coverage and might be misleading in evaluating the accuracy of dose calculation between PB and MC. Thus, the clinical quality assurance procedures required to verify the accuracy of dose calculation using PB and MC need to consider measurements of 2- and 3-dimensional dose distributions rather than a single point measurement using heterogeneous phantoms instead of homogenous water-equivalent phantoms.