bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigating the impact of collimator size variation on the single beam radiation of Gamma Knife PerfexionTM based on Monte Carlo simulation
Authors: Junios  , Irhas  , Novitrian  , Soediatmoko E , Haryanto F , Su’ud Z , Fielding A.L. 
Published: June 2020

Abstract
The Gamma Knife PerfexionTM (Elekta Oncology Systems) is a specialized stereotactic radiotherapy device that uses 192 Cobalt-60 radioactive sources. A dynamic collimator system enables three circular field sizes of 4 mm, 8 mm, and 16 mm diameter to be delivered. This study investigates the dosimetric characteristics of the three different sized collimated beams using Monte Carlo (MC) simulations. The MC simulation made use of previously calculated phase space from a Monte-Carlo model of the encapsulated Cobalt-60 sources. The collimators were modelled using the FLATFILT component module of the BEAMnrc user code. The output of the single beam radiation was stored in a circular scoring plane with a radius of 1.4 cm at source surface distance (SSD) 17.20 cm in the phase space file. The simulation parameters were used 2.1 x 109 particles, electron cut off energy (ECUT) of 0.7 MeV, and photon cut off energy (PCUT) of 0.01 MeV. To investigate the physical full width at half maximum (FWHM) and penumbra width (80-20%), the single beam profiles and mean energy were obtained using BEAMnrc/BEAMDP code. Based on the results that there was an increase of the full width at half maximum (FWHM) with the size of the collimator on the beam profile and the mean energy. The FHWM of the energy fluence profile for the collimator 4, 8, and 16 mm are 2.22, 3.90, and 7.80 mm, respectively. The FHWM of the fluence profile for the collimator sizes 4, 8, and 16 mm are 1.87, 3.87, and 7.80 mm. The FHWM of mean energy as a function of position for the collimator sizes 4, 8, and 16 mm are 2.56, 4.20, and 7.94 mm, respectively. The maximum mean energy for the collimators decreases as much as 0.0185 MeV.
Dosimetry for Intensity Modulated Radiotherapy (IMRT) Technique Using Ion Chamber Matrix (MatriXX-FFF) with Back Projection Method (Usual 6MV and 10MV)
Authors: Widodo P , Pawiro S A , Susila I P 
Published: June 2020

Abstract
Dose verification needs to be carried out on pre-treatment to get dose characteristics when using Intensity Modulated Radiotherapy (IMRT) technique. One of the dosimetry tools is 2D-array of the ionization chamber detectors which gives the measurement result in real-time, and does not require periodic calibration. However, this dosimetry tool has limited spatial resolution, it depends on the size and shape of the detector, and its result is affected by secondary electron transport from the detector wall to detector volume. These factors may lead to low verification result (gamma parameter). One technique to overcome these problems is using back-projection method. In this study, the kernel function was obtained from a square field of 4 cm by deconvolution from the comparison of MatriXX-FFF and TPS. The obtained kernel was then applied using convolution with variations of a square field, no-Build-Up and Build-Up condition, and IMRT parameter. The analysis of the gamma parameter was used to analyse the effectiveness of this method. The analysis results showed the increasing of passing grade value for all fields (0 % - 15.9 %, μ = 4.84%, σ = 4.81 %), with the highest was on some square fields, such as 4 cm and 5 cm. This indicated the dependence of kernel function to the size of the field. Moreover, the result of applying IMRT to certain case led to the increase of passing grade values.
Evaluation of Dosimetric Characterization of Homemade Bolus for Radiation Therapy
Authors: Carina C C C , Sekartaji G , Aisyah S , Nazara T , Nainggolan A , Endarko  
Published: June 2020

Abstract
The bolus is also known a tissue compensation that has material similar to body tissue and placed directly onto the skin surface for radiation therapy. This study aims to characterize and evaluate the synthesized homemade bolus using Natural Rubber, Paraffin Candle, Play-Doh, and Paraffin Wax Pure for radiation therapy using a photon beam. Several dosimetry properties of the synthesized of the bolus, including relative electron density (RED), transmission factor, attenuation coefficient, and percentage of surface dose (PSD), were investigated. All the synthesized bolus made with the same dimension of 11×11 cm2 with the thickness is 1 cm. CT-Scan was used to measure relative electron density (RED) where as LINAC 2300iX with energies 6 and 10 MV were used to evaluate percentage of surface dose. The RED value of all bolus material is in accordance with the provisions of bolus as a tissue compensation of the human body, which is almost the same as the value of HU in breast organs, skin, fat and adult bones. Large transmission factors and attenuation coefficients of each bolus correspond to bolus from paraffin candles as the default bolus of the hospital. The maximum bolus dose value increases when compared to measurements without bolus.
The Impact of Corrected-MVCT Images to Dose Distribution on Adaptive Tomotherapy: Hepatocellular Carcinoma Case
Authors: Rosalina F , Nasution N , Wibowo W E , Pawiro S A 
Published: June 2020

Abstract
Position verification before the treatment is performed to ensure the actual position to the planning position, so the dose distribution received by the tumor target would be in accordance with the planned dose. In Helical Tomotherapy (HT) treatment, the image of Megavoltage CT (MVCT) could be used to verify the patient’s position by registering the image to Kilovoltage CT (KVCT) image. The aim of this study was to evaluate the comparison from the dose distribution resulted from MVCT and KVCT image registration with and without automatic position correction at high doses. The correction in MVCT image registration to KVCT image was performed with adjustment in four HT degrees of freedom (lateral, longitudinal, vertical and rotational direction). Nine MVCT patient images with Hepatocellular Carcinoma were used with high doses therapy in 4-10 fractions using HT at Cipto Mangunkusumo Hospital. Evaluation of the dose distribution in the verification variation (the corrected and uncorrected position) was analyzed with Homogeneity Index (HI), Conformity Index (CI) and Organ at Risk. The results show that HI ranges from 0.06 to 0.3, while CI varies from 0.7 to 1. Based on these results, the position correction may less contribute to the dose distribution to the tumor target.
Kinetic energy of secondary fragments of 12C at varying incident energies in different biological media – A Monte Carlo study
Authors: Lintasan A , Convicto V , Pamisa D R , Quiñones C T 
Published: June 2020

Abstract
This is a Monte Carlo study in GATE V8.0 investigating the nuclear fragmentation when 12C beams were incident at varying energies on different biological media. The researchers used one million monoenergetic pencil beam primary carbons irradiated to water, adipose tissue, skeletal muscle and cortical bone phantoms. The target was a box with dimensions of 20 cm × 20 cm × 20 cm to approximate the size of a human head. The energy was varied at 186.7 MeV/u, 241.7 MeV/u and 308.3 MeV/u. We obtained the number of the secondary particles produced in the fragmentation. We then chose the ten most abundant fragments and determined their kinetic energy distributions. 12C was most abundant in the fragmentation followed by proton. Either 3He or 11B had the least entries. The kinetic energy was inversely proportional to particles atomic number. In most cases proton and deuteron had the largest kinetic energy. The number of secondary particles increased with increasing incident energy. The kinetic energy had maximum increase at the stopping range, whose depth varied directly with incident energy and inversely with density of each material. The results were in agreement with the Bethe-Bloch formula.
Primary activity standardization of 177Lu for calibrating commercial dose calibrator
Authors: Agusbudiman Agung , Rahmah Hidayati Nur , Ramli Martalena , Holnisar  
Published: June 2020

Abstract
Primary activity standardization of 177Lu has been conducted at the Center for Technology of Radiation Safety and Metrology-National Nuclear Energy Agency (PTKMR-BATAN) to establish a national reference standard for 177Lu measurements. The standardization was performed using a 47i(3(LS)-y coincidence counting system with digital coincidence counting (DCC) technique. The activity standardization of 177Lu gave a result of 148 kBq/g + 1.78 kBq/g at a reference time with uncertainty value evaluated at k = 2. The result was then used to establish a secondary standard by calibrating the reference ionization chamber using the ‘dialing-in’ method. A dial setting value of 024 was obtained on the standard reference IC. The new dial setting will be used in the routine calibration services of commercial dose calibrator to ensure all measurements of 177Lu are traceable to the national standards.
Effect of Computed Tomography Slice Thickness on Calculated Coronary Artery Calcium Score in the Assessment of Possible Radiation Induced Cardiac Toxicity
Authors: Alexander C. , Rajapakshe R. 
Published: June 2020

Abstract
Studies have suggested that the occurrence of radiation induced cardiac toxicity in breast cancer patients is significantly higher in women with pre-existing cardiac risk factors. Therefore, it is important to quantify the relationship between radiation induced cardiac toxicity and a measurable level of pre-existing cardiac risk such as the patient’s coronary artery calcium Agatston score. To assess the extent of coronary artery calcium present in the walls of patients’ coronary arteries before they received treatment, Agatston scores may be calculated using thoracic CT scans acquired for external beam radiotherapy planning. However, these planning CT scans can vary in slice thickness and resolution, thus complicating the calculation of calcium scores using scans with slice thicknesses other than the 3mm routinely employed for traditional Agatston scoring. The objective of this project is to quantify the effect of varying CT scan slice thickness in the calculation of coronary artery calcium scores so that a method of standardization might be developed. This is accomplished through the design, fabrication, and scanning of an anthropomorphic phantom featuring calcium inserts of varying sizes. Analysis of how the scores change with increasing slice thickness is used to construct a simple linear scaling method of standardization which corrects for varying slice thickness and the resulting partial volume distortions. A linear scaling method was successfully validated for the calculation of coronary artery calcium Agatston scores across a range of slice thicknesses increasing from 0.625 mm to 5 mm. Scaling is applied by multiplying the score by the slice thickness and dividing by 3 mm. This method is potentially applicable in any clinical or research endeavour which calls for retroactive cardiac calcium quantification. With a simple linear scaling method, external beam radiation therapy planning CT scans with slice thicknesses ranging from 0.625 mm to 5 mm can be used to calculate coronary artery calcium Agatston scores and thereby measure a patient’s level of cardiac risk before treatment.
Development of a low-cost imaging performance evaluation phantom for a generic multi-detector CT scanner
Authors: Calleja C J , Caballar R C , Peralta A 
Published: June 2020

Abstract
For quality assurance, an evaluation phantom is an important tool used to assess the imaging performance of a multi-detector CT (MDCT) scanner. In doing so, this would help to prevent the production of low-quality images that may lead to misdiagnosis and repeats of x-ray exposure. However, imaging performance test phantoms available commercially are too costly for resource-limited CT facilities to procure. This study aims to design an imaging performance evaluation phantom, fabricate a low-cost prototype of the design, and assess the suitability of use of the fabricated phantom under existing performance testing protocols. The phantom was designed according to recommended specifications from IAEA and AAPM and the prototype of the design was manufactured using engineering plastics and industrial metals through computer numerical controlled (CNC) machining and stereolithography (SLA) 3D printing. The fabricated phantom prototype was then tested with United Imaging 80-slice MDCT scanner and its usability was compared to Gammex ACR 464 phantom following the ACR QC assessment methods. This research was able to produce a three-module solid plastic phantom with a performance at par with the commercial phantom. Furthermore, the overall manufacturing cost for the fabrication of the phantom was 87% cheaper than the cost of acquiring a commercial phantom. Thus, local development of a quality assurance phantom for CT is a cost-effective solution for resource-limited facilities.
Calculation of Size-Specific Dose Estimation (SSDE) of The Pediatric’s Head for Tube Current Modulation (TCM) CT Examinations
Authors: Syaja’ah K N , Anam C , Lestari F P , Haekal M , Haryanto F 
Published: June 2020

Abstract
Computed Tomography (CT) examinations in the pediatric patient are sensitive to the impact of ionizing radiation, which gives long-term risk. In addition, the actual radiation dose delivered during CT examinations has not been well-described mainly when using tube current modulation (TCM) technique. To quantified this effect, an algorithm for calculating radiation dose is needed. Therefore, this study aims to calculate and analyze the estimated effective dose of head examinations from 3D CT images, based on the equivalent water diameter (Dw)For the TCM technique. Four pediatric patients in the 0-6-year-old age groups were examinations using Somatom Definition Flash with variation in the number of slices. CTDIvol and Tube current values were obtained from the DICOM header. There are two main parts algorithm for Dw calculation. First, images of CT data were converted to Hounsfield units (HU). Then, Dw values based on the patients contour using the K-mean cluster and morphological gradient algorithm were calculated for every slice. The coefficient factor is obtained by American Association of Physicists in Medicine (AAPM) report 220. The values then multiplied by CTDIvolto acquire values of SSDE. The results showed that the relation between SSDE and tube current was strongly correlated with R2 values of 0.982.
Determination the Ischemic Stroke of Brain MRI Based On Apparent Diffusion Coefficient (ADC) with b Value Variation
Authors: Zuhriyah A. , Muzzamil A. , Astuti S.D. , Suhariningsih  
Published: June 2020

Abstract
The Research to Determination the Ischemic Stroke of Brain MRI Based on Apparent Diffusion Coefficient (ADC) with b Value variations. The purposes of this study were to find b valuevariations of Diffusion Weighted Image (DWI), determining the optimum b value to find out the Contrast to Noise Ratio (CNR) ischemic stroke lesion in DWI image, and To determine the Diffusion Coefficient range obtained from the ADC (Apparent Diffusion Coefficient) value between old ischemic stroke and new ischemic stroke. In this research, used are 0, 500 and 1000. The result obtained b value influenceon the quality of DWI were analyzed in 30 patients suspected with old ischemic stroke and new ischemic stroke. Data analysis was done quantitatively with the Region Of Interest (ROI) directly on computer MRI image planes and were conducted statistical tests Signal to Noise Ratio (SNR) and Contrast to Noise Ratio (CNR). The highest Signal to Noise Ratio (SNR) found in b 0, while the highest Contrast to Noise Ratio (CNR) on the b 1000 s/mm
2. The statistics test show that significant SNR value of the Lesion, around the lesion, Liquor, WM, GM tissue is about 0,000 (p<0,05), while for the Contrast to Noise Ratio (CNR) of the lesion and around the lesion tissue is about 0,000 (p<0,05). This results showed that b value variation have a difference at lesion, around the lesion, Liquor, WM, GM tissue for MRI imaging quality. SNR and CNR are important aspect on imaging optimalization process to give the diagnose information. In this research, the diffusion coefficient value in new ischemic stroke is < 1 × 10−3, whereas the old ischemic stroke is > 1 × 10−3, the results showed that15 patients have new ischemic stroke and 15 patients have old ischemic stroke.
Measurement of the Whole Body, Eye Lens and Extremity Occupational Doses in Nuclear Medicine Staff at King Chulalongkorn Memorial Hospital
Authors: Sisai S , Krisanachinda A 
Published: June 2020

Abstract
Nuclear medicine staff have handled several radionuclides of gamma and beta emitters which result in obtaining occupational radiation risk. In 2018, the Government of Thailand announced the reduction of the eye lens dose limit from 150 to 20 mSv per year for the consecutive 5 years as of ICRP No. 118 in 2011. In Thailand, the personal effective dose to whole body, Hp(10) and the personal equivalent dose to the extremity, Hp(0.07) have been measured using optically stimulated luminescence dosimeter (OSLD) in nuclear medicine staffs while the personal equivalent dose to the eye lens, Hp(3) has never been measured. The objective is to measure Hp(10), Hp(3), and Hp(0.07) using OSLD in nuclear medicine staff who dispense high activity of radionuclides at King Chulalongkorn Memorial Hospital (KCMH). The correlations between the Hp(10), Hp(3) and Hp(0.07) were analyzed. The personal occupational dose has been measured in 10 nuclear medicine staff. Three sets of OSLD are attached at whole body, finger, and eye lens (left and right) of each personnel arranged by Thailand Institute of Nuclear Technology (TINT). As some radionuclides emit beta and gamma, most staff perform best practice in routine work, the short exposure time and the short range of beta rays to reach eye dosimeters which result in the estimated annual whole body, eye lens and extremity were less than the annual dose limit. The correlations between Hp(3) and Hp(10), Hp(0.07) and Hp(10), Hp(3) and Hp(0.07) had been recorded, while Hp(3) could be estimated from Hp(10).
Investigation of Image Quality for Quantitative Lu-177 in SPECT imaging: A Phantom Study
Authors: Mu’minah I A S , Hidayati N R , Widodo P , Shintawati R , Soejoko D S 
Published: June 2020

Abstract
A lutetium 177 (177Lu) radiopharmaceutical has been used for a theragnostic agent in molecular radiotherapies. This study aimed to investigate the image quality of SPECT image from 177Lu from Jaszczak Cylindrical Phantom based on tomographic uniformity, local-sphere uniformity, and signal-to-noise ratio (SNR). Data acquisitions were conducted using a SPECT/CT unit. For contrast measurement, six hollow sphere inserts with diameters of 9.9, 12.4, 15.6, 19.7, 24.8, and 31.2 mm were filled by 177Lu with radioactivity concentration 10 times higher than the warm background. Images were reconstructed using three different iterative reconstruction algorithms, including Flash3D, OSEM2D, and Wallis. All reconstructions were carried out with the same iteration number of 4, subset number of 4, and Gaussian Filter. Results for tomographic uniformity measurement were (112.47±8.40%), (114.30±9.59%), and (105.94±17.49%) counts for Flash3D, OSEM2D, and Wallis algorithms, respectively. Flash3D algorithm provided better tomographic uniformity than others, while Wallis algorithm yielded the highest noisy image with low SNR. Local-sphere uniformity and SNR tended to significantly increase for sphere diameters larger than 19.70 mm. It was concluded that the reconstruction method significantly affects the image quality in 177Lu quantification. Then, it seems that Flash3D is the best reconstruction method for 177Lu SPECT image acquisition.
Image Segmentation of Thyroid SPECT Using Edge-Based Active Contour Model
Authors: Rahmandinof Arif , Nazir Fadil , Dwihapsari Yanurita 
Published: June 2020

Abstract
Nuclear medicine is a reliable method to analyze or diagnose some type of diseases using functional imaging, for example SPECT imaging to obtain organs uptake and biodistribution. In order to get information needed, SPECT images have to be segmented first. Region of interest (ROI) method by the expertise is generally performed for image segmentation in SPECT imaging, but the task is daunting and time-consuming due to large number of images to be segmented. Among many methods that can be used for image segmentation, edge-based active contour is one of the most popular and widely used method in medical image segmentation. In addition to Level Set Method that fails to stop gradient magnitude by only using gradient information, here the edge-stop function (ESF) is proposed for edge-based active contour models to segment images with unclear boundaries using Matlab R2019a. In this study the Level Set Method with k-Nearest Neighbours classifier and fuzzy ESF are used to segment the thyroid images from the 99mTc-sestamibi SPECT imaging. The number of iterations and initialization are assessed to obtain better segmented images which closely related to segmented images using ROI technique from the experts. The results showed that the proposed method could be used for segmentation of thyroid SPECT images.
Synthesis of Bio-composite CHA/PVA/Alginate as Bone Substitute Material
Authors: Yauma Asra Dina , Dahlan Kiagus , Widya Sari Yessie 
Published: June 2020

Abstract
The main inorganic constituent of human bone is carbonated-hydroxyapatite (CHA). The CHA powder had been successfully synthesized by using chicken eggshell through microwave assisted precipitation methods. In the application, the biomaterials needed by orthopaedic doctors were in the form of scaffold. The addition of PVA and alginate to CHA can improve mechanical properties and affect the pores. The freeze-drying method was used to synthesize bio-composite scaffold. The FTIR result showed that spectrums correspond to functional group of PO4
3−, OH−, CO3
2− which were the characteristic of CHA. The elastic scaffold was produced in this research. The scaffold mechanical test results showed that the higher PVA content showed the higher mechanical properties. The phase composition was evaluated by XRD and indicated the presence of CHA. The morphology of the sample was evaluated by SEM which formed pores. These scaffolds showed good prospects for bone substitute material.
An Acoustic Analysis of Formants between Frequently Smoking Subjects and Non-smoking Subjects
Authors: Suwandi G R F , Mustajab M A , Haekal M , Khotimah S N , Haryanto F 
Published: June 2020

Abstract
Smoking is one of the factors that affect the respiratory health of human. A system of respiratory health indicators is needed to prevent the negative effects of smoking at an early stage. The relation between respiratory and vocal coordination can be analysed by measuring the formant frequencies, which indicate the spectral shaping of the human vocal tract. In this study, two groups of subjects with and without smoking habits were studied in terms of their formant frequencies. The results showed that there were statistical significance differences in the four formant frequencies between the two groups. The differences might be due to the changes in the elasticity of the oral cavity, which were affected by the smoke produced from cigarettes. Therefore, we conclude that a smoking person can be identified by the characteristics of their formant frequencies.