bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of acquisition time on image quality and visibility of Yttrium-90 Positron Emission Tomography: A phantom study
Authors: Thareeboonchai T , Buranatrivedhaya N , Sriwiang W , Charoenphun P , Chuamsaamarkkee K 
Published: June 2019

Abstract

90Y has internal pair production which enables the imaging of this isotope with positron emission tomography (PET). The acquisition time is a crucial factor which strongly influence the image quality due to very small decay branch of this isotope. Hence, the aim of this study was to evaluate the impact of acquisition time on image quality and visibility of 90Y PET. A NEMA IEC body phantom with set of fillable spheres were filled with 90Y to generate a hot lesion to background ratio of 8:1. PET image was acquired by Philips Gemini TF PET/CT scanner with acquisition time per bed varied from 15, 30, 60 and 120 minutes. Image quality was assessed by percentage hot contrast (HC), image noise (CV), signal-to-noise (SNR) ratio and visibility (VS). From a result, hot spheres and their edges were more defined as acquisition time increased. Additionally, SNR and visibility were increased with acquisition time and sphere size as expected but percentage hot contrast was decreased. Thus, this can be explained by the growing of noise at shorter acquisition times and smaller spheres. In conclusion, 90Y PET imaging was feasible but the imaging protocol should be carefully considered particularly in small object.
Classification of urinary stones based on edge detection using semi-automatic threshold
Authors: Fitri L A , Warty Y , Haryanto F , Fauzi U , Latief F D E 
Published: June 2019

Abstract
Urinary stones are commonly differentiated into four types; calcium, struvite, cystine, and uric acid. While two of them, cysteine and struvite, could not be distinguished easily, in fact, they need a different kind of treatments. Significantly, the purpose of this study was to classify of urinary stones based on edge detection using a semi-automatic threshold. Five urinary stones were scanned using eight sources voltage. The source voltage was 65, 75, …, 115 KV. The consistent parameters were set at; 0.20 rotation, 13.89 µm resolution, and 1 mm aluminum. The reconstructed images were quantified in CT Analyser 1.16.4.1. The region of interest (ROI) was a circle with a diameter of 275 pixels as well as the semi-automatic threshold were drawn on the reconstructed image. Based on the Hounsfield unit (HU) analysis, there were three groups of urinary stone on source voltage of 85 KV. The first group (struvite) has consisted of stone number 1 (461.42) and 3 (489.05). The second group (cystine) has consisted of stone number 2 (55.08) and 5 (-233.41). The third group was stone number 4 (634.18). The edge detection using semi-automatic threshold can classify five urinary stones into three types; struvite, cystine, and the other group.
Comparison study between different contrast administration protocols for routine CT thorax examination in two tertiary centres
Authors: Ibrahim NR , Karim NK A. , Shuaib IL , Osman ND , Hashim S , Phuah HF 
Published: June 2019

Abstract
The purpose of this study was to evaluate the degree of contrast enhancement and image quality of computed tomography (CT) thorax examination using different contrast administration protocols. Data was retrospectively collected from 140 patients from two centres; 70 patients (Group A) from Advanced Medical and Dental Institute (IPPT), Universiti Sains Malaysia [19 males, 51 females; mean age ± standard deviation (SD) 53.6 ± 11.2 years; mean weight ± SD 54.04 ± 13.77 kg] using automatic bolus tracking (ABT) with weight-based contrast volume (WBV) administration, and 70 patients (Group B) from Hospital Pulau Pinang (HPP), Ministry of Health Malaysia [24 males, 46 females; mean age ± SD 54.5 ± 13.2 years] using fixed time-delay (FTD) with fixed contrast volume (FV) technique. The degree of enhancement was quantified by measuring Hounsfield unit (HU) values in different arteries and veins, and rated on a 5-point scale (1 = very poor, 5 = excellent) for qualitative assessment. The mean enhancement values in Group B were found to be higher than those in Group A (P < 0.001). There was no statistically significant difference between mean qualitative scores on a 5-point scale in both groups (P = 0.185). A weak correlation was seen between HU values with administered contrast volume (r = 0.1152). Overall, FTD with FV protocol was found to have higher degree of contrast enhancement for routine CT thorax examination. The qualitative assessment showed no significant difference between both protocols although higher mean grading in CT image quality was given by assessors for ABT with WBV technique.
Phantom design for quality control of Positron Emission Tomography/Computed Tomography (PET/CT) imaging
Authors: Mu’minah I A S , Ratianto  , Nurlely  , Soejoko D S 
Published: June 2019

Abstract
This research was aimed to develop an in-house phantom for quality control (QC) of image quality in PET/CT imaging. Wax and rice powder were mixed to produce tissue-equivalent materials characterized by Hounsfield Unit (HU). The in-house phantom was two circular cylinders with 20 cm in diameter and 10 cm in length which consists of six symmetric vessel pairs with varied diameters of 4.20, 6.20, 8.30, 9.80, 16.30, and 19.00 mm. Each measurement was performed using radioactivity concentrations of 18F-FDG with variation from 1 to 17 µCi/mL Images were displayed with the pixel size of 4 × 4 mm2. Image quality was evaluated in terms of conversion factor between full-width-half-maximum (FWHM) and actual diameter, and a pixel value for local uniformity of each object. Two types of phantoms have been designed which were liver-equivalent material (LEM) and muscle-equivalent material (MEM). HU and electron densities were (74.17 ± 1.48) HU and 3.396 × 1023 electron/m3 for LEM, while (20.27 ± 0.33) HU and 3.461 × 1023 electron/m3 for MEM, respectively. The conversion factor was initially high at 2.240 ± 0.07 for diameter 4.20 mm, falls to 0.99 ± 0.003 for diameter 9.80 mm, slowly decrease up to 0.82 ± 0.01 at diameter 16.30 mm, and then nearly constant at 0.82 with increasing diameter for both phantoms. The in-house phantom could be used to analyse the image quality performance of PET imaging with a tissue-specific material. The phantom design including the development of tissue-surrogate materials, size, and geometrical considerations of the features will be beneficial for innovating QC tools.
Quantitative metrics for assessing IMRT plan conformity: A virtual phantom study
Authors: Soh H S , Langmack K A , Morgan P S , Perkins A C 
Published: June 2019

Abstract
Intensity Modulated Radiation Therapy (IMRT) is a complex form of radiation delivery for the treatment of malignant tumours and other diseases. In IMRT treatment planning, quantitative assessment is crucial to measure and improve the plan quality and treatment delivery. The search for simple and universal quantitative metrics to assess IMRT treatment plan quality has been identified as important, but as yet not entirely successful. The aim of this study was to assess the IMRT treatment plan quality from the perspective of planning conformity. Conformity index (CI) was adopted to quantify the plan conformity. Virtual phantoms were developed for the initial conformity assessment, in order to form a basis for treatment plan inter-comparisons amongst the different IMRT techniques. A series of multi organs at risk (OARs) phantoms was developed to simulate the planning target volume (PTV) and OARs for different configurations. Conformity assessments were undertaken on all the IMRT plans generated using the virtual phantoms. This study has demonstrated the successful development of virtual phantoms to assess objectively and systematically the IMRT treatment plan conformity.
Inter-comparison of phantoms for CT numbers to relative electron density (RED)/physical density calibration and influence to dose calculation in TPS
Authors: Koniarova Irena 
Published: June 2019

Abstract
Six different phantoms (2x CIRS, 1x Agmeco, 1x QUASAR, 1x Gammex, 1x CatPhan) and Varian formulas were used to evaluate their suitability for CT numbers to relative electron density (RED) calibration in the treatment planning system at two centres using two CT scanners. The variability in calibration curve and the influence to dose calculation in the TPS were estimated for 6 MV and 18 MV. The presence of scattering material around inhomogeneities and influence of CT spectra (90 kV, 120 kV, 140 kV) were evaluated. All phantoms were found convenient for calibration except CatPhan where large deviations were observed for dense bone. Phantoms without scatter material around inhomogeneities should be used with caution. Varian formula slightly overestimates calibration curve in the region of 200 - 300 HU. The tolerance level of 10% suggested for RED during commissioning is reasonable as it can cause change in dose of 3% and 1.5% for 6 MV and 18 MV respectively as a very conservative estimate. Calibration curves should be acquired for all scanning protocols with different CT spectra.
Evaluation of image quality and radiation dose in kilovoltage cone beam computed tomography
Authors: Pinsaitong N , Asavaphatiboon S , Tangboonduangjit P 
Published: June 2019

Abstract
This study was to evaluate the image quality and radiation dose of kV-CBCT when varying mAs and reconstruction filter. The radiation dosimetry (CBDIw) and quality control of kV-CBCT image were done. Routine protocols in head, thorax, and pelvis protocols were performed as a reference image. Then the images were acquired with varied mAs, the other parameters were fixed. Each technique was reconstructed with different filter. The image quality in terms of low contrast and high contrast resolution including CBDIw were compared. The result found that the variation of mAs with auto filter affected low contrast resolution, but slightly effect high contrast resolution. When mAs increased, low contrast detectability increased. Decreasing one step of mAs (16.67%) kept in acceptable image quality and reduced about 15% of CBDIw. The smooth filter improved the low contrast resolution, but it decreased the high contrast resolution. While the sharp or ultra-sharp filter improved the high contrast resolution. In conclusion, the changing of mAs affects the low contrast resolution and CBDIW. While the reconstruction filter changed the both of low and high contrast resolution, but no effect to CBDIw. To optimize the image quality and radiation dose of routine protocols, mAs can reduce one step-down.
Occupational radiation dose during fluoroscopy guided interventional procedures at Institut Kanser Negara
Authors: Bohari A , Hashim S , Mustafa S N M 
Published: June 2019

Abstract
Fluoroscopy-guided interventional (FGI) tends to involve long-term procedures that increase the fluoroscopy time and the dose area product (DAP). Therefore, radiation protection is a major concern for interventional radiology staff. This study signifies the occupational and the radiation doses for interventional radiology staff, in particular, non-physician in order to clarify the current dose level for radiographers and nurses. The occupational doses were compared among interventional radiology staff in Institut Kanser Negara (IKN), Putrajaya, Malaysia where 230 patients underwent FGI procedures were observed in one-year. The occupational doses of interventional radiologist (IR), medical officer (MO), radiographer and nurse were recorded using two optically stimulated luminescence dosimeter (OSLD), one worn over and one under their protective aprons. The occupational dose (effective dose) indicated that the IR, MO, radiographer and nurse with double OSLDs were 9.82, 7.91, 6.42 and 6.02 mSv, respectively. The effective dose of IR, MO, radiographer and nurse were 7.63, 7.91, 6.42, 5.66 mSv, respectively using a single OSLD. It has shown a statistically significant difference in the effective dose of double worn OSLDs and one OSLD of (p < 0.05) for interventional radiology staff. In both methods, IR > MO > radiographer > nurse was the highest effective dose in the interventional radiology staff. However, the occupational dose of single OSLD was found to be lower than double OSLDs. It is highly recommended that interventional radiology staff to use double OSLDs during the FGI procedures in order to determine the occupational dose accurately.
The impact of pitch and modulation factor to Tomotherapy treatment plan optimization for motion target
Authors: Kartutik K. , Wibowo Wahyu E. , Pawiro Supriyanto A. 
Published: June 2019

Abstract
The influence on target motion resulted from the respiratory process, the pitch and modulation factor presented in Tomotherapy. This study was aimed to investigate the effect of motion management using CT-images obtained from the fusion process between the static and dynamic scanning mode on the CIRS Thorax Phantom. The images were created using axial and helical modes which amplitudes were varied from 10 mm, 15 mm, and 20 mm. Then, the organ structures were planned using TomoPlan TPS with the variation of pitch ranging from 0.25 to 0.5, and the modulation factor (MF) in the range 2 to 3. Furthermore, evaluation of radiotherapy planning was performed using dose parameters on target, the organ at risk, homogeneity index (HI), and mean leaf open time (LOT). Target volume for static mode was 3.53 cc, whereas target volume has changed to 10.9 cc, 10.3 cc, 16.1 cc for axial and 6.6 cc, 8.5 cc, 14.9 cc for helical scanning. The HI value obtained was less than 0.07 and lower HI was resulted for a larger MF. It means that the higher modulation factor values will provide a uniform dose distribution to the target and lower dose to the OAR. The greater value of pitch gave the greater mean LOT. The optimum parameters were at the pitch of 0.5 and MF of 3 based on the evaluation of mean LOT and HI. Axial scanning mode provides a larger target volume compared to a helical scanning mode. Therefore, the increment of the target volume in delineating organ should be considered.
Synthesis and characterization of fluoridated hydroxyapatite nano-powder via microwave irradiation method
Authors: Wisnugroho M , Nurlely  , Sari Y W 
Published: June 2019

Abstract
Fluoridated hydroxyapatite (FHA) occur in teeth and form the basis for application as a biomaterial. This work aims to synthesize and analyze the characteristic of FHA nano-powder with different degrees of fluoridation via microwave irradiation method. FHA nano-powder with a chemical formula of Ca10(PO4)6(OH2-x
)F
x
(where degrees of fluoridation, x values were selected equal to 0.7 and 1.3) were synthesized using a mixture of calcium hydroxide, diammonium hydrogen phosphate, and ammonium fluoride solutions by utilizing microwave with the variation of irradiation power. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy analysis techniques were utilized in order to evaluate the characteristic of synthesized FHA nano-powder. The XRD and FTIR results confirmed highly crystalline FHA powder with the carbonate peaks in the IR spectrum. Using a Scherrer formula, the average crystallite size was found to be 30 nm. The SEM and EDX results indicated various element composition and several morphologies with the lattice parameter increased along with irradiation power. FHA nano-powder could be synthesized via microwave irradiation method. The results from different kind of analysis illustrated that synthesized FHA nano-powder could fulfill the requirement of ASTM F1185-88 for used as biomaterial.
Synthesis and characterization of hydroxyapatite-chitosan composite in situ by microwave irradiation method
Authors: Ersal F M , Nurlely  , Sari Y W 
Published: June 2019

Abstract
Chitosan is a natural polysaccharide which has bioresorbable, biocompatible, and non-toxic properties. The combination between chitosan and hydroxyapatite will form a nanocomposite which improves its mechanical properties and can be applied as a bone implant material. The aim of this work was synthesis and characterization of composite hydroxyapatite-chitosan through in situ way utilized by microwave irradiation with time variation. A composite which was formed by hydroxyapatite and 2% chitosan solution through in situ way were irradiated by 270-watt power for 20-60 minutes with an interval of 10 minutes. The XRD results showed peak hydroxyapatite and chitosan. Meanwhile, the highest crystallite size was found in 50 minutes composite with value 20.87 nm. The FTIR spectroscopy identified the functional group of hydroxyapatite and chitosan (NH). Increase in irradiation time caused reduction of chitosan-based on the existence of NH composition. Highest mass was present at time 20 minutes which means the reduction of mass also occurred with increasing irradiation time. The SEM and EDX results indicated the hydroxyapatite has filled chitosan matrix. The presence of NH cluster proved that microwave irradiation method can be used to synthesize nanocomposites hydroxyapatite and chitosan. Increase in irradiation time caused a reduction of chitosan existence and its mass.
Shifting landscapes: decoupled urban irrigation and greenness patterns during severe drought
Authors: Quesnel Kimberly J , Ajami Newsha , Marx Andrew 
Published: June 2019

Abstract
Urban outdoor water conservation and efficiency offer high potential for demand-side management, but irrigation, greenness, and climate interlinks must be better understood to design optimal policies. To identify paired transitions during drought, we matched parcel-level water use data from smart, dedicated irrigation meters with high-spatial resolution, multispectral aerial imagery. We examined changes across 72 non-residential parcels using potable or recycled water for large landscape irrigation over four biennial summers (2010, 2012, 2014, and 2016) that encompassed a historic drought in California. We found that despite little change in irrigation levels during the first few years of the drought, parcel greenness deteriorated. Between summers 2010 and 2014, average parcel greenness decreased −61% for potable water irrigators and −56% for recycled water irrigators, providing evidence that vegetation could not reach its vigor from wetter, cooler years as the drought intensified with abnormally high temperatures. Between summers 2014–2016 as drought severity lessened, irrigation rates decreased significantly in line with high drought saliency, but greenness rebounded ubiquitously, on average +110% for potable water irrigators and +62% for recycled water irrigators, demonstrating climate-driven vegetation recovery as evaporation and plant evapotranspiration rates decreased. Transitions were similar for customers with both potable and recycled water; vegetation changes were dominated by the overarching climatic regime. As irrigation cannot always overcome drought conditions, which will become more severe under climate change, to maintain vegetation health, utilities and urban planners should consider the tradeoffs between providing green spaces and water scarcity. This includes evaluating the roles of climate-appropriate landscaping and adaptive reallocation of potable and recycled water resources to enhance water security. By addressing emerging themes in urban water management through analysis of data from forthcoming water metering and aerial imagery technologies, this research provides a unique perspective on water use, greenness, and drought linkages.
Assessment of core and lower limb muscles for static/dynamic balance in the older people: An ultrasonographic study
Authors: Özkal Özden , Kara Murat , Topuz Semra , Kaymak Bayram , Bakı Aysun , Özçakar Levent 
Published: June 2019

Abstract

Background
sufficient research has not been conducted to determine the role of core and lower limb muscles in providing balance in older people.

Objective
to investigate the relationships between the thickness of core/lower limb muscles and static/dynamic balance in older people.

Methods
the study included a total of 68 older people (≥ 65 years) and 68 gender-matched young subjects, aged 20–40 years. Balance, knee proprioception sense, regional and total muscle measurements and grip strength were assessed using a force platform system, isokinetic dynamometer, ultrasound imaging, bioelectrical impedance analysis and Jamar dynamometer, respectively.

Results
all the static (postural sway) parameters were higher and all the dynamic (limits of stability) parameters were lower in the older adults compared to the young adults (all P<0.05). The diaphragm was thicker and all the other muscles (except for multifidus and tibialis anterior) were thinner in the older group (all P<0.05). A higher error of knee proprioception sense was determined at 45 and 70 degrees in the older subjects (both P<0.001). According to the multivariate analyses, significant predictors for balance were age, gender, height, and rectus femoris, vastus intermedius and diaphragm muscle thicknesses in the older group, and age, gender, height, grip strength, and rectus abdominis, internal oblique, longissimus, tibialis anterior and soleus muscle thicknesses in the young group (all P<0.05).

Conclusions
the thickness of core/lower limb muscles are important determinants of balance in both older and young adults. These findings could provide a strong rationale for strengthening specific (abdominal and quadriceps) muscles to prevent falls and regional sarcopenia, and to improve posture/balance in the older population.

Clinical trial registration number
NCT03791047

Ethics committee approval
Hacettepe University Non-interventional Clinical Research Ethics Board. Decision number:GO 18/506-39
Mortality Risks Associated With Dual– and Poly–Tobacco-Product Use in the United States
Authors: Choi Kelvin , Inoue-Choi Maki , McNeel Timothy S , Freedman Neal D 
Published: June 2019

Abstract
Increasing numbers of adults in the United States use more than 1 tobacco product. Most use cigarettes in combination with other tobacco products. However, little is known about the all-cause and cancer-specific mortality risks of dual– and poly–tobacco-product use. We examined these associations by pooling nationally representative data from the 1991, 1992, 1998, 2000, 2005, and 2010 National Health Interview Surveys (n = 118,144). Mortality information was obtained through linkage to the National Death Index. Cigarette smokers who additionally used other tobacco products smoked as many if not more cigarettes per day than exclusive cigarette smokers. Furthermore, cigarette smokers who additionally used other tobacco products had mortality risks that were as high as and sometimes higher than those of exclusive cigarette smokers. As tobacco use patterns continue to change and diversify, investigators in future studies need to carefully assess the impact of noncigarette tobacco products on cigarette use and determine associated disease risks.