Wahyu Setiabudi
Guru Besar Jurusan Fisika, Fakultas MIPA Universitas Diponegoro

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DISPERSION MODELING OF NATURAL RADIONUCLIDES 238U, 232TH, 226RA, 40K IN MURIA COASTAL WATERS Sasongko, Dwi Purwantoro; upriharyono, S; Setiabudi, Wahyu
JOURNAL OF COASTAL DEVELOPMENT Vol 15, No 2 (2012): Volume 15, Number 2, Year 2012
Publisher : JOURNAL OF COASTAL DEVELOPMENT

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Abstract

Dispersion modeling of natural radionuclides 238U, 232Th, 226Ra, 40K in Muria coastal waters has been carried out in sea water and sediment surounding Tanjungjati B coal-fire power plant and nuclear power plant site’s candidate by applying the hydrodynamics model of unsteady 2-dimensional flexible grid. Oceanography data collecting of bathimetry, current, wave, tide and wind had been carried out on May 28, 2006 until June 2006. Updating data was conducted on April 27 up to April 29, 2011 by using Acoustic Doppler Current Meter Profiler (ADCP) to measure the wave and subsurface current with duration of 2x24 hours. Sea water and sediment samples were collected on April 22, 2011 in six locations (surounding Tanjungjati CPP) and on April 23, 2011 in 10 locations (surounding NPP site’s candidate). Samples were analyzed at Research Center for Safety Technology and Radiation Metrology Laboratory, National Nuclear Energy Agency, Jakarta on May 2011 until September 2011 by using spectrometri-γ analysis. Result shows that it can be identified and measured the natural radionuclides of 238U, 232Th, 226Ra, 40K in sea water and sediment. The study can be justified that natural radionuclides of 238U, 232Th, 226Ra, 40K was leachated from fly ash and bottom ash of coal burned Tanjungjati CPP to sea water. The hiyrodynamics model of unsteady 2-dimensional fexible grid by using CD Oceanography software for current plotting, ArcView GIS 3.3 software for bathimetric contouring and SMS 8.1 software for modeling of natural radionuclides dispersion in coastal waters one can applied for radionuclides dispersion of 238U, 232Th, 226Ra, 40K in Muria coastal waters.
STUDI UJI ALTERNATIF KUALITAS MINYAK GORENG BERDASARKAN PERUBAHAN POLARISASI CAHAYA TERIMBAS Susan, Ade Ika; Firdausi, K Sofjan; Setiabudi, Wahyu
BERKALA FISIKA Vol 14, No 4 (2011): Berkala Fisika
Publisher : BERKALA FISIKA

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AbstractIn this research, we report the quality of several cooking oils before and after heating. The parameter of quality was based on electrooptics characteristic or, so called, the change ofpolarization angle induced by external electric field. In this examination, it was used threedifferent brands of cooking oils. The samples were heated in the time interval between 0-120minutes. The electrooptics characteristic was determined by measuring the change ofpolarization angle of light as it passed through the oil while it was applied by external electricfield. The field was produced by two parallel plates connected to different potential between 0-9kV. The light source was diode laser atλ = 650 nm and λ = 532 nm. The quality of oil was then determined by average polarization angle per potential difference, i.e. α ≡ Δθ/ΔV. Based on the result of observation, the fresh oil before heated has smaller change of polarization angle thanoil after heated, which is in agreement to the previous study. The longer heating time is, morefree radicals are produced, which leads to higher polarization. It shows also that the change ofpolarization depends on the wavelength.  From two diode lasers, the effective wavelength toproduce higher number free radicals is obtained by 532 nm. The increasing average ofpolarization angle is linearly to the increasing of heating time. It is obvious that the electroopticsparameter could be proposed as an alternative quality test of cooking oil.Keyword: Cooking oil quality, Change of polarization angle, electrooptics
SIMULASI MONTE CARLO UNTUK MENENTUKAN DOSIS SINAR-X 6 MV PADA KETAKHOMOGENAN MEDIUM JARINGAN TUBUH Rizani, Alfian; Setiabudi, Wahyu; Anam, Choirul
BERKALA FISIKA Vol 15, No 2 (2012): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Study on dose distribution of human body at 6 MV X-ray beam has been done using Monte Carlo Simulation. This study is aimed to define dose distribution of soft tissues, lungs andbones also corrections factor due to tissue inhomogeneity.The study was conducted by Monte Carlo Simulation using EGSnrc software, i.e.BEAMnrc and DOSXYZnrc. The linear accelerator head was simulated by BEAMnrc  with SSD100 cm and field size 10 x 10 cm . The calculating of radiation dose distribution at homogen andnonhomogen phantom that have size 40 x 40 x 40 cm in tissues of human body, such as softtissues, lungs and bones were made by using DOSXYZnrc. Nonhomogen phantom of human bodywas made by insert lungs or bones with thickness 10 cm in soft tissues at depth of 5 cm – 14 cm.It is obtained that the dose distribution of soft tissue and water phantom have samecharacteristic which both of them have maximum dose (D ) at depth of 1,5 cm. Inserting of lungswith a thickness of 10 cm in soft tissue results to the increasing of dose until 12,2 % and insertingof bones with the same thickness with lungs results to decreasing of dose until 10,3 %. The rangeof correction factor due to inserting lungs is 1,00–1,27 and for bone is 0,81–1,05.Keywords:Monte Carlo Simulation, PDD (Percentage Depth Dose), corrections factor
UPAYA PENINGKATAN KUALITAS CITRA MRI DENGAN PEMBERIAN MEDIA KONTRAS Suhardi, Suhardi; Setiabudi, Wahyu; Anam, Choirul
BERKALA FISIKA Vol 16, No 1 (2013): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Improvement the image quality of magnetic resonance imaging (MRI) carried out bycontrast media has been done. It was expected to obtain a better image quality so thatinterpretation of MRI images more valid. Contrast media were used gadolinium 5 mmol/10 ml perpatient. Number of patients 10 people with tumor of the head, and each uses a 6 slices. MRI usedAIRIS II with 0.3 Tesla magnetic field, Kodak Dry View 8900, densitometry, and Film. In thisstudy, the image resulted with and without contrast media were measured its density andcompared. It was resulted that the image density in normal  tissues no change, with and withoutcontrast media. While the tumor area with and without contrast media, the density decreased byan average of 0,56. The addition of contrast media, the presence of tumor will appear moreclearly.Keywords: Contrast Media, gadolinium, MRI
KAJIAN RADIOGRAFI DIGITAL TULANG TANGAN Susilo, Susilo; Setiabudi, Wahyu; Kusminarto, Kusminarto; Suparta, G. B.
BERKALA FISIKA Vol 16, No 1 (2013): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Teknologi diagnostik medis yang digunakan pada unit radiologi di rumah sakit sudahcenderung bergeser dari teknologi analog berbasis film menjadi teknologi digital (filmless). Salahsatu cara membuat system radiografi tanpa film adalah dengan cara konversi digital menggunakantabung kedap cahaya (light tight tube). Dalam penelitian ini, kami telah mengkaji kemungkinanpemanfaatan sistem pencitraan radiografi digital sinar-x berbasis X-Ray Intensifying Screen(XRIS) dihubungkan dengan perangkat frame-grabber. Hasil eksperimen tahap awal untukmemperoleh radiograf tulang tangan menunjukkan bahwa sistem ini cukup dioperasikan padategangan anode-katode 50 kV, arus waktu filamen 50 mAs dan waktu paparan 0,1 detik untukmenghasilkan citra yang cukup dapat dilihat. Untuk sekali paparan, dimungkinkan memperolehbeberapa citra untuk obyek yang sama pada posisi tetap, tipa-tiap citra mengandung informasiradiografi berbeda ditunjukkan oleh distribusi tiap citra yang bervariasi. Hasil ini menunjukkanbahwa sistem ini diharapkan lebih efisien dan lebih efektif dibandingkan dengan metodekonvensional berbasis film, dan dapat dikembangkan untuk diagnose mineral tulang.Kata kunci: radiografi digital; filmless; sinar-x; tulang tangan
KORELASI NILAI TIME REPETITION (TR) DAN TIME ECHO (TE) TERHADAP SIGNAL TO NOISE RATIO (SNR) PADA CITRA MRI Aji Prastowo, Alan Tanjung; Setiabudi, Wahyu; Anam, Choirul
BERKALA FISIKA Vol 16, No 4 (2013): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Effort to obtain a correlation of TR and TE to the value of Signal to Noise Ratio (SNR) in MRI machine has been carried out. In this research used MRI Hitachi Airis II which has a permanentmagnetic field of 0.3 Tesla. Research using a phantom object with Polyethylene Vessel containingNiCl2: 18 mmol/l. Phantom has a tube diameter 165 mm, cap diameter 120 cm and height 320 mm.Image acquisition is done with two TE value of 20 ms and 120 ms, and TR values varied from 100 msto 4000 ms, with the scale of 100 ms. Slice taken with a thickness 5 mm, and in the position 15 cm fromthe bottom of phantom. Region of interest (ROI) in the image is determined at the radius of 65 cm.SNR calculation is then performed for a variety of TE and TR. It was obtained that the SNR valueincreases exponentially for TR value of 100 ms to 700 ms and stabilized at the next TR to 4000 ms. Atthe same TR, SNR value at TE 20 ms greater than the TE 120 ms. At TE 20 ms, TR optimal value forT1WI is at 700 ms, with a SNR value of 57,6 ms, whereas for PD image on TR 3900 ms with a SNR of57,6. At TE 120 ms, TR optimal value for T2WI was at 2200 ms with SNR value of 19.Keywords: Magnetic Resonance Imaging (MRI), Time Repetition (TR), Time Echo (TE), Signal toNoise Ratio (SNR)
Evaluasi Ketebalan Irisan (Slice Thickness) pada Pesawat CT-Scan Single Slice Makmur, I Wayan Ari; Setiabudi, Wahyu; Anam, Choirul
SAINS DAN MATEMATIKA Volume 21 Nomor 2 Tahun 2013
Publisher : SAINS DAN MATEMATIKA

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Abstract

An evaluation of the value of the slice thickness due to changes in tube voltage and tube current on the CT scan have been performed. The evaluation is done by making images using CT performance test phantom. Testing is done by performing three scanning on each slice. Exposure factors used were 120 kVp-60 mA, 160 mA 120-kVp, 140-kVp 60 mA, and 140 kVp 160 mA. Nominal beam width were 2 mm, 3 mm, 5 mm, 7 mm, and 10 mm. Once the axial image was obtained (on the area for slice thickness determination),  then calculated the average CT number on the region of interest (ROI). After it was made graphs to determine the value of FWHM which indicates the magnitude of the thickness of the slice. From the test results obtained that changes in tube voltage and tube current does not affect the value of the thickness of the slice. Also found that the value of slice thickness for each thickness, greater than the nominal beam width.   Keywords: Phantom CT Performance Test, Slice Thickness, CT-Scan
Studi Uniformitas Dosis Radiasi CT Scan pada Fantom Kepala yang Terletak pada Sandaran Kepala Retnoningsih, Dwi Siwi; Anam, Choirul; Setiabudi, Wahyu
SAINS DAN MATEMATIKA Volume 20 Nomor 2 Tahun 2012
Publisher : SAINS DAN MATEMATIKA

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Abstract

The research on the impact of tube current and  tube voltage  on uniformity of the point dose in the head phantom was placed on the table, had been conducted. The research was carried out on the CT Scan machine, Siemens Somatom Emotion 6. The detector used was CT dose profiler and Piranha Electrometer 556. The phantom was head phantom with PMAA material with diameter 16 cm and length 15 cm. The measurement of point dose carried out by using axial mode. The measurement conducted in five points inside the head phantom. In this research, the tube current and tube voltage were varied. The results show that the point dose on the head phantom was placed on the table is non-uniform. At the bottom of the phantom, the dose is lower to below 50% than at the top of the phantom.   Keywords: CT Scan, Dose uniformity, Point Dose, CTDI
Pengaruh Perubahan Tegangan Tabung (kVp) Terhadap CT Number dan Uniformitasnya pada Pesawat CT Scan S., Anugrah Ariyani; Setiabudi, Wahyu; Anam, Choirul
SAINS DAN MATEMATIKA Volume 20 Nomor 3 Tahun 2012
Publisher : SAINS DAN MATEMATIKA

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An examination of consistency of CT numbers and its uniformity due to variation of the tube voltage has been done. The examination was conducted using water and polyethyelene phantoms as a test object. The method of scanning, which are  axial  scanning  and helical scanning. The scanning was taken 5 (five) slices with slice thickness of 5 mm. Variations in  tube voltage used were 80 kV, 120 kV and 140 kV.  The tube current 160 mA and time scanning 2 seconds. It was obtained that the increase in voltage from 80 kV to 140 kV led to increase the value of CT number both for water and polyethylene phantoms. The uniformity of CT number for all ROI varies, but still within the range of tolerance limits. The CT number for the water phantom does not exceed 0 ± 5 HU and for polyethylene phantom does not exceed -300 to -100 HU..   Keywords: CT Scan, CT number, uniformity, tube voltage (kV)
Analisis Perubahan Kurva Percentage Depth Dose (PDD) dan Dose Profile untuk Radiasi Foton 6MV pada Fantom Thoraks Prasetyo, Nur Dwi; Setiabudi, Wahyu; Anam, Choirul
SAINS DAN MATEMATIKA Volume 20 Nomor 4 Tahun 2012
Publisher : SAINS DAN MATEMATIKA

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The study of thickness variation of the soft tissue in the wall of thoracic phantom to the shifting of Percentage Depht Dose (PDD) curve and Dose Profile have been done by using Monte Carlo Simulation. The linac head was designed using BEAMnrc software, whereas modeling of water and thoracic phantom using DOSXYZnrc software. The field size of beam radiation 10 x10 cm2 and the distance of source to  phantom surface (SSD) 100 cm. The water phantom in cubic shape with a size  40x40x40 cm3. The thoracic phantom was designed in cubic shape, with the compositions: soft tissue, bone and lung. The thickness of the soft tissue in the wall of throcic phantom was varied 1-5 cm. This variation shows the thickness layer of the wall of the real patients. The results of comparation between monte carlo simulation and the  actual measurement, show that 6 MV photon delivered by linac at Kensaras Hospital Semarang was generated using energy electron about  5.7 MeV. The variation of soft tissue thickness change  the PDD curve and the dose profile curve. The variation of soft tissue thickness change the dose in the lung (depth 10 cm)  at about 3,84% - 5,59%   Keywords: Monte Carlo Simulation, Percentage Depht Dose (PDD), Dose profle, Tissue inhomogeneity