Search results for: dose length product

Authors: Babina Aryal

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Background: The diagnosis of pancreatitis is generally based on clinical and laboratory findings; however, Computed Tomography (CT) is an imaging technique of choice specially Contrast Enhanced Computed Tomography (CECT) shows morphological characteristic findings that allow for establishing the diagnosis of pancreatitis and determining the extent of disease severity which is done along with the administration of appropriate contrast medium. The purpose of this study was to compare Computed Tomography Dose Index (CTDI), Dose Length Product (DLP) and Effective Dose (ED) among male and female patients from Contrast Enhanced Computed Tomography (CECT) Pancreatitis Protocol. Methods: This retrospective study involved data collection based on clinical/laboratory/ultrasonography diagnosis of Pancreatitis and has undergone CECT Abdomen pancreatitis protocol. data collection involved detailed information about a patient's Age and Gender, Clinical history, Individual Computed Tomography Dose Index and Dose Length Product and effective dose. Results: We have retrospectively collected dose data from 150 among which 127 were males and 23 were females. The values obtained from the display of the CT screen were measured, calculated and compared to determine whether the CTDI, DLP and ED values were similar or not. CTDI for females was more as compared to males. The differences in CTDI values for females and males were 32.2087 and 37.1609 respectively. DLP values and Effective dose for both the genders did not show significant differences. Conclusion: This study concluded that there were no more significant changes in the DLP and ED values among both the genders however we noticed that female patients had more CTDI than males.

Keywords: computed tomography, contrast enhanced computed tomography, computed tomography dose index, dose length product, effective dose

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Authors: S. Gharbi, S. Labidi, M. Mars, M. Chelli, F. Ladeb

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The purpose of this study is to reduce radiation dose for chest CT examination by including Tube Current Modulation (TCM) to a standard CT protocol. A scan of an anthropomorphic male Alderson phantom was performed on a 128-slice scanner. The estimation of effective dose (ED) in both scans with and without mAs modulation was done via multiplication of Dose Length Product (DLP) to a conversion factor. Results were compared to those measured with a CT-Expo software. The size specific dose estimation (SSDE) values were obtained by multiplication of the volume CT dose index (CTDIvol) with a conversion size factor related to the phantom’s effective diameter. Objective assessment of image quality was performed with Signal to Noise Ratio (SNR) measurements in phantom. SPSS software was used for data analysis. Results showed including CARE Dose 4D; ED was lowered by 48.35% and 51.51% using DLP and CT-expo, respectively. In addition, ED ranges between 7.01 mSv and 6.6 mSv in case of standard protocol, while it ranges between 3.62 mSv and 3.2 mSv with TCM. Similar results are found for SSDE; dose was higher without TCM of 16.25 mGy and was lower by 48.8% including TCM. The SNR values calculated were significantly different (p=0.03<0.05). The highest one is measured on images acquired with TCM and reconstructed with Filtered back projection (FBP). In conclusion, this study proves the potential of TCM technique in SSDE and ED reduction and in conserving image quality with high diagnostic reference level for thoracic CT examinations.

Keywords: anthropomorphic phantom, computed tomography, CT-expo, radiation dose

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Authors: Khaled Soliman, Abdullah Alrushoud, Abdulrahman Alkhalifah, Raed Albathi, Salman Altymiat

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Radiation dose received by patients undergoing Computed Tomography (CT) examination of the cervical spine was evaluated using Gafchromic XR-QA2 films and CT-EXPO software (ver. 2.3), in order to document our clinical dose values and to compare our results with other benchmarks reported in the current literature. Radiochromic films were recently used as practical dosimetry tool that provides dose profile information not available using the standard ionisation chamber routinely used in CT dosimetry. We have developed an in-house program to use the films in order to calculate the Entrance Dose Length Product (EDLP) in (mGy.cm) and to relate the EDLP to various organ doses calculated using the CT-EXPO software. We also calculated conversion factor in (mSv/mGy.cm) relating the EDLP to the effective dose (ED) from the examination using CT-EXPO software. Variability among different types of CT scanners and dose modulation methods are reported from at least three major CT brands available at our medical institution. Our work describes the dosimetry method and results are reported. The method can be used as in-vivo dosimetry method. But this work only reports results obtained from adult female anthropomorphic Phantom studies.

Keywords: CT dosimetry, gafchromic films, XR-QA2, CT-Expo software

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Authors: Lateef Bamidele

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Over the years, radiographic examinations are the most used diagnostic tools in the Nigerian health care system, but most diagnostic examinations carried out do not have records of patient doses. Lack of adequate information on patient doses has been a major hindrance in quantifying the radiological risk associated with radiographic examinations. This study aimed at estimating dose–area product (DAP) of patient examined in X-Ray units in selected hospitals in Southern Nigeria. The standard projections selected are chest posterior-anterior (PA), abdomen anterior-posterior (AP), pelvis AP, pelvis lateral (LAT), skull AP/PA, skull LAT, lumbar spine AP, lumbar spine, LAT. Measurement of entrance surface dose (ESD) was carried out using thermoluminescent dosimeter (TLD). Measured ESDs were converted into DAP using the beam area of patients. The results show that the mean DAP ranged from 0.17 to 18.35 Gycm². The results obtained in this study when compared with those of NRPB-HPE were found to be higher. These are an indication of non optimization of operational conditions.

Keywords: dose–area product, radiographic examinations, patient doses, optimization

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Authors: Chao Sima, Shanaz Ghandhi, Sally A. Amundson, Michael L. Bittner, David J. Brenner

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In a large-scale radiologic emergency, potentially affected population need to be triaged efficiently using various biomarkers where personal dosimeters are not likely worn by the individuals. It has long been established that radiation injury can be estimated effectively using panels of genetic biomarkers. Furthermore, the rate of radiation, in addition to dose of radiation, plays a major role in determining biological responses. Therefore, a better and more accurate triage involves estimating both the dose level of the exposure and the length of time of that exposure. To that end, a large in vivo study was carried out on mice with internal emitter caesium-137 (¹³⁷Cs). Four different injection doses of ¹³⁷Cs were used: 157.5 μCi, 191 μCi, 214.5μCi, and 259 μCi. Cohorts of 6~7 mice from the control arm and each of the dose levels were sacrificed, and blood was collected 2, 3, 5, 7 and 14 days after injection for microarray RNA gene expression analysis. Using a generalized linear model with penalized maximum likelihood, a panel of 244 genes was established and both the doses of injection and the number of days after injection were accurately predicted for all 155 subjects using this panel. This has proven that microarray gene expression can be used effectively in radiation biodosimetry in predicting both the dose levels and the length of exposure time, which provides a more holistic view on radiation exposure and helps improving radiation damage assessment and treatment.

Keywords: caesium-137, gene expression microarray, multivariate responses prediction, radiation biodosimetry

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Authors: Alireza Shayegan, Morteza Amirabadi

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The y tool was developed to quantitatively compare dose distributions, either measured or calculated. Before computing ɣ, the dose and distance scales of the two distributions, referred to as evaluated and reference, are re-normalized by dose and distance criteria, respectively. The re-normalization allows the dose distribution comparison to be conducted simultaneously along dose and distance axes. Several two-dimensional images were acquired using a Scanning Liquid Ionization Chamber EPID and Extended Dose Range (EDR2) films for regular and irregular radiation fields. The raw images were then converted into two-dimensional dose maps. Transitional and rotational manipulations were performed for images using Matlab software. As evaluated dose distribution maps, they were then compared with the corresponding original dose maps as the reference dose maps.

Keywords: energetic electron, gamma function, penumbra, Matlab software

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Authors: M. M. M. Jaradat

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For a given graph G, the set Ԑ of all subsets of E(G) forms an |E(G)| dimensional vector space over Z2 with vector addition X⊕Y = (X\Y ) [ (Y \X) and scalar multiplication 1.X = X and 0.X = Ø for all X, Yϵ Ԑ. The cycle space, C(G), of a graph G is the vector subspace of (E; ⊕; .) spanned by the cycles of G. Traditionally there have been two notions of minimality among bases of C(G). First, a basis B of G is called a d-fold if each edge of G occurs in at most d cycles of the basis B. The basis number, b(G), of G is the least non-negative integer d such that C(G) has a d-fold basis; a required basis of C(G) is a basis for which each edge of G belongs to at most b(G) elements of B. Second, a basis B is called a minimum cycle basis (MCB) if its total length Σ BϵB |B| is minimum among all bases of C(G). The lexicographic product GρH has the vertex set V (GρH) = V (G) x V (H) and the edge set E(GρH) = {(u1, v1)(u2, v2)|u1 = u2 and v1 v2 ϵ E(H); or u1u2 ϵ E(G) and there is α ϵ Aut(H) such that α (v1) = v2}. In this work, a construction of a minimum cycle basis for the wreath product of wheels with paths is presented. Also, the length of the longest cycle of a minimum cycle basis is determined. Moreover, the basis number for the wreath product of the same is investigated.

Keywords: cycle space, minimum cycle basis, basis number, wreath product

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Authors: Saad Bin Saeed, Fayzan Ahmed, Shahbaz Ahmed, Amjad Hussain

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The aim of this study is to evaluate dynamic log files (Dynalogs) at different dose rates by dose-volume histograms (DVH) and used as a (QA) procedure of IMRT. Seven patients of phase one head and neck cancer with similar OAR`s are selected randomly. Reference plans of dose rate 300 and 600 MU/Min with prescribed dose of 50Gy in 25 fractions for each patient is made. Dynalogs produced by delivery of reference plans processed by in-house MATLAB program which produces new field files contain actual positions of multi-leaf collimators (MLC`s) instead of planned positions in reference plans. Copies of reference plans are used to import new field files generated by MATLAB program and renamed as Dyn.plan. After dose calculations of Dyn.plans for different dose rates, DVH, and multiple linear regression tools are used to evaluate reference and Dyn.plans. The results indicate good agreement of correlation between different dose rate plans. The maximum dose difference among PTV and OAR`s are found to be less than 5% and 9% respectively. The study indicates the potential of dynalogs to be used as patient-specific QA of IMRT at different dose rate.

Keywords: IMRT, dynalogs, dose rate, DVH

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Authors: R. Tudugala, B. M. A. I. Balasooriya, W. M. Ediri Arachchi, R. W. M. W. K. Rathnayake, T. D. Premaratna

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Brachytherapy involves placing a source of radiation near the cancer site which gives promising prognosis for cervical cancer treatments. The purpose of this study was to evaluate the effect of random variation of treated volumes in between fractions in the 2D image based fractionated high dose rate brachytherapy for cervical cancer at National Cancer Institute Maharagama, Sri Lanka. Dose plans were analyzed for 150 cervical cancer patients with orthogonal radiographs (2D) based brachytherapy. ICRU treated volumes was modeled by translating the applicators with the help of “Multisource HDR plus software”. The difference of treated volumes with respect to the applicator geometry was analyzed by using SPSS 18 software; to derived patient population based estimates of delivered treated volumes relative to ideally treated volumes. Packing was evaluated according to bladder dose, rectum dose and geometry of the dose distribution by three consultant radiation oncologist. The difference of treated volumes depends on types of the applicators, which was used in fractionated brachytherapy. The means of the “Difference of Treated Volume” (DTV) for “Evenly activated tandem (ET)” length” group was ((X_1)) -0.48 cm3 and ((X_2)) 11.85 cm3 for “Unevenly activated tandem length (UET) group. The range of the DTV for ET group was 35.80 cm3 whereas UET group 104.80 cm3. One sample T test was performed to compare the DTV with “Ideal treatment volume difference (0.00cm3)”. It is evident that P value was 0.732 for ET group and for UET it was 0.00 moreover independent two sample T test was performed to compare ET and UET groups and calculated P value was 0.005. Packing was evaluated under three categories 59.38% used “Convenient Packing Technique”, 33.33% used “Fairly Packing Technique” and 7.29% used “Not Convenient Packing” in their fractionated brachytherapy treatments. Random variation of treated volume in ET group is much lower than UET group and there is a significant difference (p<0.05) in between ET and UET groups which affects the dose distribution of the treatment. Furthermore, it can be concluded nearly 92.71% patient’s packing were used acceptable packing technique at NCIM, Sri Lanka.

Keywords: brachytherapy, cervical cancer, high dose rate, tandem, treated volumes

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Authors: Hacer Yeldan, Erhan Akamca, Sedat Gündogdu

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Length-Weight and Length-length relationship were estimated of 14 species Sparidae (Boops boops, Diplodus annularis, Diplodus cervinus, Dipladus puntazzo, Diplodus sargus, Diplodus vulgaris, Lithognathus mormyrus, Oblada melanura, Pagellus acarne, Pagellus erythrinus, Pagrus auriga, Pagrus caeruleostictus, Sarpa salpa, Sparus aurata) sampled from in the Northeastern Mediterranean Sea coast of Turkey, Iskenderun Bay. Samples were collected from July 2014 to June 2015, using bottom trawl and trammel net into three different depth; 0-10 m, 10-20 m, 20-50m. Length-length relationships were determined size measurements: standard length (SL) and fork length (FL) to total length (TL) for fish species. The relationships between TL, FL and TL, SL were all linear. The values of the exponent b of the length-weight relationships ranged between 2.685 and 3.473. The type of growth for fish species was algometric growth.

Keywords: Sparidae, Iskenderun bay, length-length, length-weight relationships

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Authors: H. Yousefnia, S. Zolghadri, S. Shanesazzadeh, A.Lahooti, A. R. Jalilian

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In this study, 68Ga-ECC and 67Ga-ECC were both prepared with the radiochemical purity of higher than 97% in less than 30 min. The biodistribution data for 68Ga-ECC showed the extraction of the most of the activity from the urinary tract. The absorbed dose was estimated based on biodistribution data in mice by the medical internal radiation dose (MIRD) method. Comparison between human absorbed dose estimation for these two agents indicated the values of approximately ten-fold higher after injection of 67Ga-ECC than 68Ga-ECC in the most organs. The results showed that 68Ga-ECC can be considered as a more potential agent for renal imaging compared to 67Ga-ECC.

Keywords: effective absorbed dose, ethylenecysteamine cysteine, Ga-67, Ga-68

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Authors: Aya Al Masri, Stefaan Carpentier, Fabrice Leroy, Thibault Julien, Safoin Aktaou, Malorie Martin, Fouad Maaloul

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Introduction: During an 'Interventional Radiology (IR)' procedure, the patient's skin-dose may become very high for a burn, necrosis and ulceration to appear. In order to prevent these deterministic effects, an accurate calculation of the patient skin-dose mapping is essential. For most machines, the 'Dose Area Product (DAP)' and fluoroscopy time are the only information available for the operator. These two parameters are a very poor indicator of the peak skin dose. We developed a mathematical model that reconstructs the magnitude (delivered dose), shape, and localization of each irradiation field on the patient skin. In case of critical dose exceeding, the system generates warning alerts. We present the results of its comparison with clinical studies. Materials and methods: Two series of comparison of the skin-dose mapping of our mathematical model with clinical studies were performed: 1. At a first time, clinical tests were performed on patient phantoms. Gafchromic films were placed on the table of the IR machine under of PMMA plates (thickness = 20 cm) that simulate the patient. After irradiation, the film darkening is proportional to the radiation dose received by the patient's back and reflects the shape of the X-ray field. After film scanning and analysis, the exact dose value can be obtained at each point of the mapping. Four experimentation were performed, constituting a total of 34 acquisition incidences including all possible exposure configurations. 2. At a second time, clinical trials were launched on real patients during real 'Chronic Total Occlusion (CTO)' procedures for a total of 80 cases. Gafchromic films were placed at the back of patients. We performed comparisons on the dose values, as well as the distribution, and the shape of irradiation fields between the skin dose mapping of our mathematical model and Gafchromic films. Results: The comparison between the dose values shows a difference less than 15%. Moreover, our model shows a very good geometric accuracy: all fields have the same shape, size and location (uncertainty < 5%). Conclusion: This study shows that our model is a reliable tool to warn physicians when a high radiation dose is reached. Thus, deterministic effects can be avoided.

Keywords: clinical experimentation, interventional radiology, mathematical model, patient's skin-dose mapping.

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Authors: Chengbin Wang, Li Lu, Luodan Suo, Qinghai Wang, Fan Yang, Xu Wang, Mona Marin

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Background: Two-dose varicella vaccination has been recommended in Beijing since November 2012. We investigated a varicella outbreak in a highly vaccinated elementary school population to examine transmission patterns and risk factors for vaccine failure. Methods: A varicella case was defined as an acute generalized maculopapulovesicular rash without other apparent cause in a student attending the school from March 28 to May 17, 2015. Breakthrough varicella was defined as varicella >42 days after last vaccine dose. Vaccination information was collected from immunization records. Information on prior disease and clinical presentation was collected via survey of students’ parents. Results: Of the 1056 school students, 1028 (97.3%) reported no varicella history, of whom 364 (35.4%) had received 1-dose and 650 (63.2%) had received 2-dose varicella vaccine, for 98.6% school-wide vaccination coverage with ≥ 1 dose before the outbreak. A total of 20 cases were identified for an overall attack rate of 1.9%. The index case was in a 2-dose vaccinated student who was not isolated. The majority of cases were breakthrough (19/20, 95%) with attack rates of 7.1% (1/14), 1.6% (6/364) and 2.0% (13/650) among unvaccinated, 1-dose, and 2-dose students, respectively. Most cases had < 50 lesions (18/20, 90%). No difference was found between 1-dose and 2-dose breakthrough cases in disease severity or sociodemographic factors. Conclusion: Moderate 2-dose varicella vaccine coverage was insufficient to prevent a varicella outbreak. Two-dose breakthrough varicella is still contagious. High 2-dose varicella vaccine coverage and timely isolation of ill persons might be needed for varicella outbreak control in the 2-dose era.

Keywords: varicella, outbreak, breakthrough varicella, vaccination

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Authors: Liqian Li, Yu Liu, Karen Colins

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The dose rate present in a seriously contaminated area can be indirectly determined by monitoring radiation damage to inexpensive commercial electronics, instead of deploying expensive radiation hardened sensors. EEPROMs (Electrically Erasable Read Only Memories) are a good candidate for this purpose because they are inexpensive and are sensitive to radiation exposure. When the total ionizing dose threshold is reached, an EEPROM chip will show signs of damage that can be monitored and transmitted by less susceptible electronics. The dose rate can then be determined from the known threshold dose and the exposure time, assuming the radiation field remains constant with time. Therefore, the threshold dose needs to be well understood before this method can be used. There are many factors affecting the threshold dose, such as the gamma ray energy spectrum, the operating voltage, etc. The purpose of this study was to experimentally determine how the threshold dose depends on dose rate, temperature, voltage, and duty factor. It was found that the duty factor has the strongest effect on the total ionizing dose threshold, while the effect of the other three factors that were investigated is less significant. The effect of temperature was found to be opposite to that expected to result from annealing and is yet to be understood.

Keywords: EEPROM, ionizing radiation, radiation effects on electronics, total ionizing dose, wireless sensor networks

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Authors: Alina Zafar

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In this particular research, various morphometric characters such as total length (TL), wet weight (WW), standard length (SL), fork length (FL), head length (HL), head width (HW), body depth (BD), body girth (BG), dorsal fin length (DFL), pelvic fin length (PelFL), pectoral fin length (PecFL), anal fin length (AFL), dorsal fin base (DFB), anal fin base (AFB), caudal fin length (CFL) and caudal fin width (CFW) of wild collected Puntius sophore were studied, to know the types of growth patterns and correlations in reference to length and weight, however, high significant relationships were recorded between total length and wet weight, as the correlation coefficient (r) possessed value of 0.989. The growth pattern was observed to be positively allometric as the value of ‘b’ was 3.22 (slightly higher than the ideal value, 3) with 95% confidence intervals ranging from 3.076 to 3.372. Wet weight and total length parameters showed high significant correlations (p < 0.001) with all other morphometric characters.

Keywords: Puntius sophore, length and weight relation, morphometrics, small indigenous species

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Authors: G. E. Okungbowa, H. O. Adams, S. E. Eze

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This study is on the estimation of adult patient doses for Chest X-ray diagnostic examinations of new admitted undergraduate students attending a tertiary institution health centre as part of their routine clearance and check up on admitted into the institution. A total of 531 newly admitted undergraduate students were recruited for this survey in the first quarter of 2016 (January to March, 2016). CALDOSE_X 5.0 software was used to compute the Entrance Surface Dose (ESD) and Effective Dose (ED); while the Statistical Package for Social Sciences (SPSS) version 21.0 was used to carry out the statistical analyses. The basic patients' data and exposure parameters required for the software are age, sex, examination type, projection posture, tube potential and current-time product. The mean Entrance Surface Dose and Effective Doses of the undergraduate students were calculated using the software, and the values were compared with existing literature and internationally established diagnostic reference levels. The mean ESD calculated is 0.29 mGy, and the mean effective dose is 0.04 mSv. The values of ESD and ED obtained are below the internationally established diagnostic reference levels, which could be attributed to good radiographic techniques employed during the chest X-ray procedure for these students.

Keywords: x-ray, dose, examination, chest

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Authors: S. Zolghadri, M. Naderi, H. Yousefnia, A. Ramazani, A. R. Jalilian

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The aim of this work was to evaluate the values of absorbed dose of 68Ga-DOTATOC in numerous human organs. 68Ga-DOTATOC was prepared with the radiochemical purity of higher than 98% and by specific activity of 39.6 MBq/nmol. The complex demonstrated great stability at room temperature and in human serum at 37° C at least 2 h after preparation. Significant uptake was observed in somatostatin receptor-positive tissues such as pancreas and adrenal. The absorbed dose received by human organs was evaluated based on biodistribution studies in Syrian rats by the radiation absorbed dose assessment resource (RADAR) method. Maximum absorbed dose was obtained in the pancreas, kidneys, and adrenal with 0.105, 0.074, and 0.010 mGy/MBq, respectively. The effective absorbed dose was 0.026 mSv/MBq for 68Ga-DOTATOC. The results showed that 68Ga-DOTATOC can be considered as a safe and effective agent for clinically PET imaging applications.

Keywords: effective absorbed dose, Ga-68, octreotide, MIRD

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Authors: Atcharawan Phenwansuk

Abstract:

The product design is important to the development of SME towards the global, because it made to the quality product to react the needs of consumers and could reduces cost in the production, making it more profitable. As a results, the business are competition advantage for more marketing. It also enhance image of product and firms to build its own brand products to be acceptable. The product was designed should be shape, size, colorful, and direct of target consumers. This is method to add value products to get popular and effective, because the beauty is first satisfaction which come from main shape and color of the design product, but the product was designed need to hold data and law combination of shape and color between artistic theory and satisfaction of consumers together. The design must consider the safety of life and asset of consumers the most important. From to use of designed products should be to consider the cost savings, convenient distance, transportation, routes (land, water or air) of living space on transport (capacity, volume, width, length of the car, truck and container, etc). The packaging must be can to prevent not damage of the products. If products is more large , maybe to design new packaging, which can easily disassembled for make smaller package such as designing the assembly. Products must be packed in the container for size standard for save costs, as well as the buyer can make transport and assembly of products to fit easily on your own.

Keywords: logistics process , pineapple’s leaves product, product design, satisfaction of consumers

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Authors: S. Sina, B. Zeinali, M. Karimipourfard, F. Lotfalizadeh, M. Sadeghi, E. Zamani, M. Zehtabian, R. Faghihi

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Proper dosimetery is very essential in diagnostic radiology. The goal of this study is to verify the application of LiF:Mg, Cu, P (TLD100H) in obtaining the entrance skin dose (ESD) of patients undergoing diagnostic radiology. The results of dosimetry performed by TLD-100H were compared with those obtained by TLD100, which is a common dosimeter in diagnostic radiology. The results show a close agreement between the dose measured by the two dosimeters. According to the results of this study, the TLD-100H dosimeters have higher sensitivities (i.e. signal(nc)/dose) than TLD-100. Therefore, it is suggested that the TLD-100H are effective dosimeters for dosimetry in low dose fields.

Keywords: entrance skin dose, TLD, diagnostic radiology, dosimeter

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Authors: T. S. Shashikumar

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Radon is a radioactive gas emitted from radium, a daughter product of uranium that occurs naturally in rocks and soil. Radon, together with its decay products, emits alpha particles that can damage lung tissue. The activity concentration of ²²²Ra has been analyzed in water samples collected from borewells and rivers in and around Hassan city, Karnataka State, India. The measurements were performed by Emanometry technique. The concentration of ²²²Rn in borewell waters varies from 18.49±1.89 to 397.26±12.3 Bql^-1 with geometric mean 120.48±12.87 Bql^-1 and in river waters it varies from 92.63±9.31 to 93.98±9.51 Bql^-1 with geometric mean of 93.16±9.33 Bql^-1. In the present study, the radon concentrations are higher in Adarshanagar and Viveka Nagar which are found to be 397.26±12.3 Bql^-1 and 325.78±32.56 Bql^-1. Most of the analysed samples show a ²²²Rn concentration more than 100 Bql^-1 and this can be attributed to the geology of the area where the ground waters are located, which is predominantly of granitic characteristic. The average inhalation dose and ingestion dose in the borewell water are found to be 0.405 and 0.033 µSvy^-1; and in river water it is found to be 0.234 and 0.019 µSvy^-1, respectively. The average total effective dose rate in borewell waters and river waters are found to be 0.433 and 0.253 µSvy^-1, which does not cause any health risk to the population of Hassan region.

Keywords: borewell, effective dose, emanometry, 222Rn

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Authors: Chia-Hui Chen, Chien-Kuo Wang

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Background: Full field digital mammography (FFDM) is widely used in diagnosis of breast cancer. Digital breast tomosynthesis (DBT) has recently been introduced into the clinic and is being used for screening for breast cancer in the general population. Hence, the radiation dose delivered to the patients involved in an imaging protocol is of utmost concern. Aim: To compare the surface radiation dose (ESD) of digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM) by using breast phantoms. Method: We analyzed the average entrance surface dose (ESD) of FFDM and DBT by using breast phantoms. Optically Stimulated luminescent Dosimeters (OSLD) were placed in a tissue-equivalent Breast phantom at difference sites of interest. Absorbed dose measurements were obtained after digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM) exposures. Results: An automatic exposure control (AEC) is proposed for surface dose measurement during DBT and FFDM. The mean ESD values for DBT and FFDM were 6.37 mGy and 3.51mGy, respectively. Using of OSLD measured for surface dose during DBT and FFDM. There were 19.87 mGy and 11.36 mGy, respectively. The surface exposure dose of DBT could possibly be increased by two times with FFDM. Conclusion: The radiation dose from DBT was higher than that of FFDM and the difference in dose between AEC and OSLD measurements at phantom surface.

Keywords: full-field digital mammography, digital breast tomosynthesis, optically stimulated luminescent dosimeters, surface dose

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Authors: Samir Karimov, Elshad Abdullayev, Muslum Gurbanov

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As one of the γ-radiolysis products of hexachlorocyclohexane and hexachlorobenzene, the study of 1.4 g/L concentrated 1,2,4-trichlorobenzene (TCB) in methanol solution has been irradiated at 0-209.3 kGy dose of γ-radiation and the results have been studied via GC-MS. At maximum radiation dose of 209.3 kGy 91.38% of TCB has converted into different organic compounds, such as 1,4-, 1,3- and 1,2- dichlorobenzenes (DCB), chlorobenzene, toluene, benzene and other chlorinated and non-chlorinated compounds. The variation of compounds formed by γ-radiolysis depends on the nature of solvent and radiation dose. One of the frequently identified radiolysis products of TCB in different organic solvents - 1,4-DCB studied quantitatively with external standard. The concentration of DCB increases by increasing absorbed radiation dose to approximately 131.8 kGy, then at higher doses with its conversion into chlorobenzene, it decreases.

Keywords: γ-radiolysis, chlorinated pesticides, radiation dose, dechlorination

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Authors: Khalid A. Rabaeh, Belal Moftah, Ahmed A. Basfar, Akram A. Almousa

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Polymer gel dosimeters are tissue equivalent martial that fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of absorbed radiation dose. Polymer gel dosimeters can uniquely record the radiation dose distribution in three-dimensions (3D). A novel composition of normoxic polymer gel dosimeters based on radiation-induced polymerization of N-(Hydroxymethyl)acrylamide (NHMA) is introduced in this study for radiotherapy treatment planning. The dosimeters were irradiated by 10 MV photon beam of a medical linear accelerator at a constant dose rate of 600 cGy/min with doses up to 30 Gy. The polymerization degree is directly proportional to absorbed dose received by the polymer gel. UV/Vis spectrophotometer was used to investigate the degree of white color of irradiated NHMA gel which is associated to the degree of polymerization of polymer gel dosimeters. The absorbance increases with absorbed dose for all gel dosimeters in the dose range between 0 and 30 Gy. Dose rate , energy of radiation and the stability of the polymerization after irradiation were investigated. No appreciable effects of these parameters on the performance of the novel gel dosimeters were observed.

Keywords: dosimeter, gel, spectrophotometer, N-(Hydroxymethyl)acrylamide

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Authors: Kiyohiro Yamazaki

Abstract:

The purpose of this paper is to examine the hypothesis explaining the mechanism in the case, where the product is deleted or reduced the fundamental function of the product through the product concept changes in the digital camera industry. This paper points out not owning the fundamental technology might cause the change of the product concept. Casio could create new competitive factor so that this paper discusses a possibility of the mechanism of changing the product concept.

Keywords: firm without fundamental technology, product development, product concept, digital camera industry, Casio

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Authors: Muhammad Naeem, Amina Zubari, Abdus Salam, Summera Yasmeen, Syed Ali Ayub Bukhari, Abir Ishtiaq

Abstract:

In the present study, eighty three wild Oreochromis aureus of different body size ranging 5.3-14.6 cm in total length were collected from the River Chenab, District Muzzafer Garh, Pakistan to investigate the parameters of length –weight, length-length relationships and condition factor in relation to size. Each fish was measured and weighed on arrival at laboratory. Log transformed regressions were used to test the allometric growth. Length-weight relationship was found highly significant (r = 0.964; P < 0.01). The values of exponent “ b” in Length–weight regression (W=aLb), deviated from 3, showing isometric growth (b = 2.75). Results for LLRs indicated that these are highly correlated (P< 0.001). Condition factor (K) found constant with increasing body weight, however, showed negative influence with increasing total length.

Keywords: Oreochromis aureus, weight-length relationship, condition factor, predictive equations

Procedia PDF Downloads 791

Authors: M. Derraz, M.Farhaoui

Abstract:

In the water treatment processes, the determination of the optimal dose of the coagulant is an issue of particular concern. Coagulant dosing is correlated to raw water quality which depends on some parameters (turbidity, ph, temperature, conductivity…). The objective of this study is to provide water treatment operators with a tool that enables to predict and replace, sometimes, the manual method (jar testing) used in this plant to predict the optimum coagulant dose. The model is constructed using actual process data for a water treatment plant located in the middle of Morocco (Meknes).

Keywords: coagulation process, aluminum sulfate, model, coagulant dose

Procedia PDF Downloads 242

Authors: Wizna, Helmi Muis, Hafil Abbas

Abstract:

An experiment was conducted to improve the nutrient value of sago pith (Metroxylon sago Rottb) supplemented with Zn, Sulfur and urea through fermentation by using cellulolytic bacteria (Bacillus amyloliquefaciens) as inoculums. The experiment was determination of the optimum dose combination (dosage of Zn, S and urea) for sago pith fermentation based on nutrient quality and quantity of these fermented products. The study was conducted in experimental method, using the completely randomized design in factorial with 3 treatments consist of: factor A (Dose of urea: A1 = 2.0%, A2 = 3.0%), factor B (Dose of S: B1 = 0.2%, B2 = 0.4%) and factor C (Dose of Zn: C1 = 0.0025%, C2 = 0.005%). Results of study showed that optimum condition for fermentation process of sago pith with B. amyloliquefaciens caused a change of nutrient content was obtained at urea (3%), S (0,2%), and Zn (0,0025%). This fermentation process was able to increase amino acid average, reduce crude fiber content by 67% and increase crude protein by 433%, which made the nutritional value of the product based on dry matter was 18.22% crude protein, 12.42% crude fiber, 2525 Kcal/kg metabolic energy and 65.73% nitrogen retention.

Keywords: fermentation, sago pith, sulfur, Zn, urea, Bacillus amyloliquefaciens

Procedia PDF Downloads 481

Authors: Lenon M. Pereira, Helen J. Khoury, Marcos E. A. Andrade, Dean L. Cutajar, Vinicius S. M. Barros, Anatoly B. Rozenfeld

Abstract:

With the increase of beam widths and the advent of multiple-slice and helical scanners, concerns related to the current dose measurement protocols and instrumentation in computed tomography (CT) have arisen. The current methodology of dose evaluation, which is based on the measurement of the integral of a single slice dose profile using a 100 mm long cylinder ionization chamber (Ca,100 and CPPMA, 100), has been shown to be inadequate for wide beams as it does not collect enough of the scatter-tails to make an accurate measurement. In addition, a long ionization chamber does not offer a good representation of the dose profile when tube current modulation is used. An alternative approach has been suggested by translating smaller detectors through the beam plane and assessing the accumulated dose trough the integral of the dose profile, which can be done for any arbitrary length in phantoms or in the air. For this purpose, a MOSFET dosimeter of small dosimetric volume was used. One of its recently designed versions is known as the MOSkin, which is developed by the Centre for Medical Radiation Physics at the University of Wollongong, and measures the radiation dose at a water equivalent depth of 0.07 mm, allowing the evaluation of skin dose when placed at the surface, or internal point doses when placed within a phantom. Thus, the aim of this research was to characterize the response of the MOSkin dosimeter for X-ray CT beams and to evaluate its application for the accumulated dose assessment. Initially, tests using an industrial x-ray unit were carried out at the Laboratory of Ionization Radiation Metrology (LMRI) of Federal University of Pernambuco, in order to investigate the sensitivity, energy dependence, angular dependence, and reproducibility of the dose response for the device for the standard radiation qualities RQT 8, RQT 9 and RQT 10. Finally, the MOSkin was used for the accumulated dose evaluation of scans using a Philips Brilliance 6 CT unit, with comparisons made between the CPPMA,100 value assessed with a pencil ionization chamber (PTW Freiburg TW 30009). Both dosimeters were placed in the center of a PMMA head phantom (diameter of 16 cm) and exposed in the axial mode with collimation of 9 mm, 250 mAs and 120 kV. The results have shown that the MOSkin response was linear with doses in the CT range and reproducible (98.52%). The sensitivity for a single MOSkin in mV/cGy was as follows: 9.208, 7.691 and 6.723 for the RQT 8, RQT 9 and RQT 10 beams qualities respectively. The energy dependence varied up to a factor of ±1.19 among those energies and angular dependence was not greater than 7.78% within the angle range from 0 to 90 degrees. The accumulated dose and the CPMMA, 100 value were 3,97 and 3,79 cGy respectively, which were statistically equivalent within the 95% confidence level. The MOSkin was shown to be a good alternative for CT dose profile measurements and more than adequate to provide accumulated dose assessments for CT procedures.

Keywords: computed tomography dosimetry, MOSFET, MOSkin, semiconductor dosimetry

Procedia PDF Downloads 279

Authors: Idris Garba, Aisha Rabiu Abdullahi, Mansur Yahuza, Akintade Dare

Abstract:

Background: CT urography (CTU) is efficient radiological examination for the evaluation of the urinary system disorders. However, patients are exposed to a significant radiation dose which is in a way associated with increased cancer risks. Objectives: To determine Computed Tomography Dose Index following CTU, and to evaluate organs equivalent doses. Materials and Methods: A prospective cohort study was carried at a tertiary institution located in Kano northwestern. Ethical clearance was sought and obtained from the research ethics board of the institution. Demographic, scan parameters and CT radiation dose data were obtained from patients that had CTU procedure. Effective dose, organ equivalent doses, and cancer risks were estimated using SPSS statistical software version 16 and CT dose calculator software. Result: A total of 56 patients were included in the study, consisting of 29 males and 27 females. The common indication for CTU examination was found to be renal cyst seen commonly among young adults (15-44yrs). CT radiation dose values in DLP, CTDI and effective dose for CTU were 2320 mGy cm, CTDIw 9.67 mGy and 35.04 mSv respectively. The probability of cancer risks was estimated to be 600 per a million CTU examinations. Conclusion: In this study, the radiation dose for CTU is considered significantly high, with increase in cancer risks probability. Wide radiation dose variations between patient doses suggest that optimization is not fulfilled yet. Patient radiation dose estimate should be taken into consideration when imaging protocols are established for CT urography.

Keywords: CT urography, cancer risks, effective dose, radiation exposure

Procedia PDF Downloads 302

Authors: Marzieh Jafarzadeh, Fatemeh Rezaee

Abstract:

Introduction: The effect of ionizing radiation on human health can be effective for genomic integrity and cell viability. It also increases the risk of cancer and malignancy. Therefore, X-ray behavior and absorption dose calculation are considered. One of the applicable tools for calculating and evaluating the absorption dose in human tissues is Monte Carlo simulation. Monte Carlo offers a straightforward way to simulate and integrate, and because it is simple and straightforward, Monte Carlo is easy to use. The Monte Carlo BEAMnrc code is one of the most common diagnostic X-ray simulation codes used in this study. Method: In one of the understudy hospitals, a certain number of CT scan images of patients who had previously been imaged were extracted from the hospital database. BEAMnrc software was used for simulation. The simulation of the head of the device with the energy of 0.09 MeV with 500 million particles was performed, and the output data obtained from the simulation was applied for phantom construction using CT CREATE software. The percentage of depth dose (PDD) was calculated using STATE DOSE was then compared with international standard values. Results and Discussion: The ratio of surface dose to depth dose (D/Ds) in the measured energy was estimated to be about 4% to 8% for bone and 3% to 7% for bone marrow. Conclusion: MC simulation is an efficient and accurate method for simulating bone marrow and calculating the absorbed dose.

Keywords: Monte Carlo, absorption dose, BEAMnrc, bone marrow

Procedia PDF Downloads 184