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"Penelitian ini bertujuan untuk membuat fantom dengan komposisi perbandingan antara hidroksiapatit dan gypsum yang paling sesuai dengan tulang manusia. Pengujian dilakukan dengan memperhatikan tiga parameter, yaitu nilai Hounsfield Unit (HU), densitas elektron (ρe), dan nomor atom efektif (Zeff). Enam sampel fantom dipersiapkan dengan perbandingan komposisi massa antara hidroksiapatit dan gypsum sebesar 100:0; 80:20; 60:40; 40:60; 20:80; 0:100. Pengujian dilakukan dengan menggunakan pemindai CT pada dua tingkat energi yang berbeda, yaitu energi rendah (tegangan tabung 80 kV) dan energi tinggi (tegangan tabung 140 kV) dengan menggunakan metode DEEDZ. Hasil perhitungan menggunakan nilai HU menghasilkan nilai densitas elektron pada keenam sampel fantom dengan akurasi sampel 1 (96.78%), sampel 2 (94.16%), sampel 3 (93.15%), sampel 4 (86.97%), sampel 5 (86.04%) dan sampel 6 (71.05%). Perhitungan juga mendapati nilai nomor atom efektif pada keenam sampel fantom dengan akurasi sebagai berikut sampel 1 (74.19%), sampel 2 (72.88%), sampel 3 (74.35%), sampel 4 (74.74%), sampel 5 (73.99%) dan sampel 6 (71.32%). Untuk parameter densitas elektron, akurasi tertinggi didapatkan dari sampel 1 (96.78%). Sedangkan hasil uji nomor atom efektif memberikan akurasi kurang dari 75% untuk seluruh sampel. Hal ini disebabkan oleh berat molekul yang menyebabkan adanya absorpsi fotolistrik. Fantom dengan bahan hidroksiapatit telah berhasil dibuat dan perlu investigasi lebih lanjut.

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The purpose of this research is to find a mass composition ratio of hydroxyapatite and gypsum to construct bone fantomsimiliar as human bone. Three parameters were selected to evaluate the constructed fantom which are Hounsfield Unit (HU), electron density (ρe), and effective atomic number (Zeff). Six fantom samples were prepared with a mass composition ratio between hydroxyapatite and gypsum as follows: 100:0; 80:20; 60:40; 40:60; 20:80; 0:100. The test was carried out by using CT Scan with low and high energies (80 kV and 140 kV tube voltages) using DEEDZ method. Hounsfield Unit values that were obtained then calculated to determine electron density, with result accuracies of 96.78%, 94.16%, 93.15%, 86.97%, 86.04% and 71.07% for samples 1, 2, 3, 4, 5, and 6, respectively. Subsequent calculation of effective atomic numbers were obtained with accuracies of 74.19%, 72.88%, 74.35%, 74.74%, 73.99%, and 71.32% respectively, for samples 1, 2, 3, 4, 5, and 6. For electron density, the highest accuracy were obtained from sample 1 (96.78%), while effective atomic number tests yielded on accuracies below 75% for all samples. This might be caused by the molecular weight being prone to photoelectric absorption. Hydroxyapatite based fantom has been successfully constructed with needs of further investigations."

"ABSTRAKKomposisi batu saluran kemih dapat mempengaruhi pilihan dalam perawatan pasien. Nilai Hounsfield Unit (HU) dapat memprediksi komposisi batu, begitu juga dengan pH urin. Kami mengevaluasi kombinasi nilai HU dan pH urin dalam prediksi komposisi batu saluran kemih. Studi potong lintang terhadap 35 pasien urolitiasis dilakukan dari Januari hingga Desember 2018 di Rumah Sakit Haji Adam Malik, Medan. Data nilai HU, pH urin, dan hasil analisis batu dikumpulkan. Hasil analisis batu dikategorikan menjadi batu dengan komposisi utama asam urat dan kalsium. Analisis HU dan pH antara kedua kelompok tersebut menggunakan uji-t tidak berpasangan. Receiver Operating Characteristic (ROC) digunakan untuk menganalisis hubungan antara HU dan pH dengan komposisi batu. Dari 35 pasien, 14 memiliki batu dengan komposisi utama asam urat dan 21 batu dengan komposisi utama kalsium. Rata-rata HU dari batu dengan komposisi utama asam urat dan kalsium adalah masing-masing 445 (± 155,3) dan 943 (± 284,0), sedangkan pH rata-ratanya masing-masing adalah 5,3 (± 0,46) dan 6,5 (± 0,64). Ada perbedaan signifikan antara nilai HU dan pH dari kedua kelompok (p <0,0001 dan p <0,0001). Hasil penelitian ini menunjukkan bahwa nilai HU dan pH urin dapat digunakan sebagai prediktor pembeda batu asam urat dari batu kalsium pada analisis batu.

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ABSTRACTUrinary stone composition may affect the treatment of choice for patients. Hounsfield Unit (HU) and urinary pH may help predict the composition of urinary stones. We evaluated HU and urinary pH combination in the prediction of urinary stone composition. A cross-sectional study on 35 urolithiasis patients were performed from January to December 2018 in Haji Adam Malik Hospital, Medan. Data on HU, urinary pH, and stone analysis results were collected. Stone analysis results were categorized into predominantly uric acid and calcium. We analyzed HU and pH between the two groups using independent T-test. Receiver operating characteristic (ROC) were used to analyze the relationship between HU and pH and the stone composition. Among 35 patients, 14 stones were predominantly uric acid and 21 stones were predominantly calcium. The mean HU of the predominantly uric acid and calcium were 445 (±155.3) and 943 (±284.0) respectively, while the mean pH was 5.3 (± 0.46) and 6.5 (± 0.64). There is a statisticallysignificant difference of HU and pH between the two groups (p<0.0001 and p<0.0001). Our study results showed that HU and urinary pH can be used as predictors to differentiate uric acid stones from calcium stones in stone analysis."

"Penelitian ini bertujuan untuk mengevaluasi perhitungan dosis berdasarkan citra Cone Beam Computed Tomography (CBCT) pada pasien dengan diagnosa tumor otak. Perencanaan dan perhitungan dosis berdasarkan citra CBCT fraksinasi ke-16 yang dilakukan terhadap 13 pasien yang disinari menggunakan pesawat linac Elekta Versa HD dan 7 pasien yang disinari menggunakan pesawat linac Halcyon 2.0. Perencanaan dan perhitungan dosis dilakukan pada Treatment Planning System (TPS) Eclipse dan TPS Monaco. Hasil perhitungan dosis berdasarkan citra CBCT dibandingkan dengan citra Computed Tomography (CT) simulator. Penelitian ini memiliki beberapa tahapan, (1) kalibrasi Hounsfield Unit (HU) citra CBCT menggunakan fantom CIRS CT electron density 062M untuk melakukan perhitungan dosis di TPS dengan nilai HU yang sesuai, (2) proses pengumpulan data citra pasien yang memenuhi kriteria penelitian dan dilanjutkan dengan proses registrasi dan perencanaan citra CBCT, (3) analisis Dose Volume Histogram (DVH) untuk mengevaluasi kualitas perencanaan dengan parameter dosis yaitu Conformity Index (CI) dan Homogeneity Index (HI), (4) analisis dosis Organ at Risk (OAR) terhadap dose-constraint (batas dosis) untuk OAR batang otak, kiasma, sumsum tulang belakang, saraf optik, mata dan lensa. Nilai CI pada perencanaan berdasarkan CT tidak berbeda secara signifikan, Berdasarkan CBCT dari pesawat linac Elekta Versa HD diperoleh CI sebesar 0,05±0,21 (p=0,08) dan -0,01 ± 0,06 (p=0,02) berdasarkan CBCT dari pesawat linac Halcyon 2.0. Sementara itu, nilai HI pada perencanaan berdasarkan CBCT diamati berbeda secara signifikan terhadap CT, Berdasarkan CBCT dari pesawat linac Elekta Versa HD diperoleh HI sebesar 0,25 ± 0,43 (p=0,01) dan 0,08 ± 0,04 (p=0,01) berdasarkan CBCT dari pesawat linac Halcyon 2.0.

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This research aims to evaluate dose calculations based on Cone Beam Computed Tomography (CBCT) images in patients diagnosed with brain tumors. Planning and dose calculations based on the 16th fraction of CBCT images were performed on 13 patients irradiated using Elekta Versa HD linear accelerator and 7 patients irradiated using Halcyon 2.0 linear accelerator. The planning and dose calculations were conducted using the Treatment Planning System (TPS) Eclipse and TPS Monaco. The results of the dose calculations based on CBCT images were compared with the Computed Tomography (CT) simulator images. The research comprised several stages: (1) calibration of Hounsfield Unit (HU) of CBCT images using CIRS CT electron density 062M phantom to perform dose calculations in TPS with appropriate HU values, (2) data collection of patient images meeting the research criteria followed by image registration and CBCT planning, (3) analysis of Dose Volume Histogram (DVH) to evaluate planning quality using dose parameters such as Conformity Index (CI) and Homogeneity Index (HI), (4) analysis of dose to Organs at Risk (OAR) against dose constraints for OARs such as brainstem, chiasm, spinal cord, optic nerves, eyes, and lenses. The CI values for the planning based on CT were not significantly different. Based on CBCT from Elekta Versa HD linear accelerator, the CI obtained was 0.05 ± 0.21 (p=0.08), and based on CBCT from Halcyon 2.0 linear accelerator, the CI obtained was -0.01 ± 0.06 (p=0.02). However, the HI values for planning based on CBCT significantly differed from CT. Based on CBCT from Elekta Versa HD linear accelerator, the HI obtained was 0.25 ± 0.43 (p=0.01), and based on CBCT from Halcyon 2.0 linear accelerator, the HI obtained was 0.08 ± 0.04 (p=0.01)."

"Tujuan dari penelitian ini adalah untuk menemukan material ekuivalen jaringan spesifik pada rentang energi radiodiagnostik (80 kV hingga 140 kV) yang terbuat dari bahan anorganik sebagai komposisi alternatif fantom dan analisis melalui parameter Hounsfield Unit (HU), densitas elektron (e) dan nomor atom efektif (Zeff). Masing-masing komposisi akan diuji menggunakan metode Dual-Energi Computed Tomography (DECT) untuk mengetahui karakteristik sampel melalui besaran HU dan diolah hingga memperoleh nilai densitas elektron (e) dan nomor atom efektif (Zeff). Hasil kalkulasi diperoleh pada material ekuivalen jaringan dan organ untuk densitas elektron (e) adalah tulang (24.90%), hati (2.62%), otot (1.17%), otak (1.01%) dan adipose (2.60%) sedangkan untuk nomor atom efektif (Zeff) adalah tulang (11.36%), hati (13.62%), otot (9.66%), otak (8.80%) dan adipose (9.34%). Dari hasil tersebut, dapat disimpulkan bahwa uji kelayakan material ekuivalen jaringan menggunakan kalkulasi parameter metode Dual-Energy Computed Tomography (DECT) menunjukkan tingkat akurasi yang cukup baik.

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The purpose of this study was to find tissue-specific equivalent material in radiodiagnostic energy range (80 kV to 140 kV) made of inorganic materials as an alternative phantom composition and analysis through Hounsfield Unit (HU), electron density (e) and effective atomic number (Zeff) parameters. Each composition will be tested using the Dual-Energy Computed Tomography (DECT) method to determine the characteristics of the sample using the HU scale and processed into the quantity of electron density (e) and effective atomic number (Zeff). The calculation on tissue and organ equivalent materials shows bone (24.90%), liver (2.62%), muscle (1.17%), brain (1.01%) and adipose (2.60%) for electron density (e) and bone (11.36%), liver (13.62%), muscle (9.66%), brain (8.80%) and adipose (9.34%) for effective atomic number (Zeff). From these results, it can be concluded that the feasibility test of tissue equivalent material using the parameter calculation of the Dual-Energy Computed Tomography (DECT) method shows a relatively acceptable level of accuracy."

"Fantom merupakan material ekuivalen jaringan tubuh yang berfungsi untuk menyimulasikan interaksi radiasi yang terjadi. Keberadaan fantom di bidang medis menjadikan proses quality assurance (QA), quality control (QC) dan treatment planning system tidak perlu mengekspos jaringan tubuh asli. Tujuan dari penelitian ini adalah menentukan komposisi fantom organik (berbahan dasar lilin dan karbon aktif) juga memperoleh nilai exit dose fantom organik melalui variasi ketebalan serta korelasinya terhadap koefisien atenuasi. Komposisi fantom tersebut didapatkan melalui kesesuaian terhadap nilai CT number (dalam satuan HU) jaringan tubuh manusia. Komposisi bahan organik penyusun fantom berdasarkan penelitian ini untuk material ekuivalen lemak adalah 10% lilin cecek, 10% karbon dan 80% lilin parafin, otot 10% lilin cecek, 10% karbon dan 80% gondorukem, otak white matter 16% lilin cecek, 16% karbon dan 68% gondorukem, otak grey matter 20% lilin cecek, 20% karbon dan 60% gondorukem dan hati 40% tepung beras, dan 60% lilin cecek. Pengukuran exit dose dilakukan pada ketebalan fantom mulai dari 6 cm hingga 10 cm serta ukuran lapangan 20 cm × 20 cm dan 25 cm × 25 cm. Persentase penurunan nilai exit dose di ketebalan 10 cm relatif terhadap ketebalan 6 cm pada ukuran lapangan 20 cm x 20 cm menunjukkan nilai sebesar (29,1% ± 4,4%); (43,7% ± 2,7%); (43,0% ± 1,2%); (41,4% ± 0,4%); (51,2% ± 5,7%) untuk material ekuivalen jaringan lemak, otot, otak white matter, otak grey matter, dan hati secara berturut – turut. Sedangkan pada ukuran lapangan 25 cm × 25 cm menunjukkan nilai sebesar (30,0% ± 2,3%); (41,2% ± 2,6%); (41,9% ± 2,1%); (40,4% ± 1,1%); (47,5% ± 4,7%). Berdasarkan hasil tersebut menunjukkan bahwa, nilai exit dose berkurang seiring dengan bertambahnya ketebalan fantom. Hal serupa ditunjukkan oleh pengurangan ukuran lapangan yang menyebabkan berkurangnya nilai exit dose. Sementara itu, nilai dosis serap dan buildup factor menunjukkan hasil yang bertolak belakang dengan nilai exit dose, di mana penambahan ketebalan fantom menyebabkan naiknya dosis serap.

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Phantom is an equivalent body tissue material that has always been used to simulate radiation interactions. the needs to expose human body with radiation in the process of QA, QC, and treatment planning system is no longer needed since the existence of phantom in the medical field. The purpose of this study is to determine the composition of organic phantom (wax and activated carbon) and also obtain the value of the exit dose of organic phantom through variations in thickness and its correlation to the attenuation coefficient. The phantom composition was obtained through conformity to the value of the CT number (in HU unit) human body tissue. The composition of the organic phantom for fat is 10% cecek wax, 10% activated carbon and 80% paraffin wax, muscle 10% cecek wax, 10% activated carbon and 80% gondorukem, brain white matter 16% cecek wax, 16% activated carbon and 68% gondorukem, brain gray matter 20% cecek wax, 20% activated carbon and 60% gondorukem and liver 40% rice flour, and 60% gondorukem wax. Exit dose was measured with phantom thickness variations ranging from 6 cm to 10 cm and field sizes of 20 cm × 20 cm and 25 cm × 25 cm. The decrease in percentage of exit dose based on thickness increment of the size of the field 20 cm x 20 cm were (29,1% ± 4,4%); (43,7% ± 2,7%); (43,0% ± 1,2%); (41,4% ± 0,4%); (51,2% ± 5,7%) for equivalent material fat, muscle, white matter brain, gray matter brain, and liver respectively. Whereas the size of the field 25 cm × 25 cm were (30,0% ± 2,3%); (41,2% ± 2,6%); (41,9% ± 2,1%); (40,4% ± 1,1%); (47,5% ± 4,7%). Based on these results it showed that the value of the exit dose decreases with increasing thickness of the phantom. The same results were showed by the reduction in the size of the field which causes a decrease in the value of exit dose. Meanwhile, the absorption dose value and buildup factor showed the opposite results with the exit dose value, where the phantom thickness increment."

"ABSTRAKPenelitian ini membahas mengenai studi kelayakan material ekuivalen jaringan spesifik pada rentang energi radiodiagnostik 80 kV hingga 130 kV , yang dikontruksi menggunakan campuran bahan organik berupa tepung beras dan lilin batik gondorukem, cecek, parafin . Dari hasil studi pendahuluan, didapatkan 4 jenis komposisi material ekuivalen, yaitu material ekuivalen jaringan adiposa, jaringan otot, jaringan otak dan organ hati. Masing-masing komposisi material ekuivalen jaringan kemudian akan melalui dua jenis metode uji, yaitu metode Dual Energy Computed Tomography DECT untuk mengetahui karakteristik sampel melalui besaran Hounsfield Unit HU, dan metode stoikiometri menggunakan Energy Dispersive Spectroscopy EDS untuk mengetahui karakteristik sampel melalui susunan jenis atom. Masing-masing data dari kedua metode kemudian akan diolah hingga mendapat nilai densitas elektron ?e dan nomor atom efektif Zeff . Hasil kalkulasi untuk metode uji DECT pada material ekuivalen jaringan adiposa, jaringan otot, jaringan otak dan organ hati menunjukan kesalahan literatur minimum sebesar 0,605 ; 0,732 ; 0,751 ; 0,670 untuk densitas elektron ?e dan 26,345 ; 26,417 ; 25,089 ; 24,617 untuk nomor atom efektif Zeff. Sedangkan untuk metode Stoikiometri, pengukuran dianggap tidak akurat karena atom hidrogen yang tidak dapat terdeteksi. Dari hasil tersebut, dapat disimpulkan bahwa tingkat akurasi metode DECT lebih baik dibandingkan metode stoikiometri, dengan hasil analisa dari keempat sampel menunjukan kesesuaian respon terhadap jaringan target, namun hanya pada jenis energi tinggi 130kV.

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ABSTRACTThis research discusses the feasibility study of tissue specific equivalent material in radiodiagnostic energy range 80 kV to 130 kV, that are made from organic mixtures rice flour and waxes for batik gondorukem, cecek, paraffin . From the preliminary study, we obtain four types of equivalent material compositions, which are equivalent to adipose, muscle, brain, and liver. Each of the compositions will be evaluated using two methods, which is Dual Energy Computed Tomography DECT method in order to discover characteristic through Hounsfield Unit HU scale, and Stoichiometry with Energy Dispersive Spectroscopy EDS in order to discover characteristic through atoms composition. The test result then processed into the quantity of electron density e and effective atomic number Zeff . From DECT method, calculation of adipose, muscle, brain, and liver equivalent materials shows minimum literature error 0,605 0,732 0,751 0,670 for electron density e and 26,345 26,417 25,089 24,617 for effective atomic number Zeff . While for the Stoichiometric method, the measurement is considered inaccurate because the hydrogen atom cannot be detected. From these results, it can be concluded that the DECT method has better accuracy compared to stoichiometry method, which the four samples have a similar response that represents tissue target, but only when exposed with high energy 130kV ."

"Dalam penelitian ini, beberapa jenis lilin (gondorukem, cecek, beeswax, parafin) dan Karbon digunakan sebagai konstituen dari bahan phantom setara jaringan. Jaringan Tubuh yang menjadi ruang lingkup penelitian adalah lemak, otot, hati, serta materi putih dan abu-abu materi di otak. Studi kelayakan material dilakukan dengan uji HU. nilai menggunakan CT scan dengan tegangan rendah 80 kVp dan tinggi 130 kVp, dan menguji koefisien atenuasi menggunakan mesin x-ray dengan tegangan 70 kVp dan pada kondisi file standar RQA 5 dengan tegangan 82 kVp. Dari hasil uji nilai HU, diperoleh komposisi dan perbandingan bahan penyusun phantom material yaitu bahan ekuivalen lemak [10 (cecek) : 10 (karbon) : 80 (parafin)], otot [10 (cecek) : 10 (karbon) : 80 (gondorukem)], hati [60 (cecek) : 40 (tepung beras)], otak putih [16 (cecek) : 16 (karbon) : 68 (gondorukem)], dan materi abu-abu otak [20 (cecek) : 20 (karbon) : 60 (gondorukem)]. Dalam pengujian koefisien redaman massa, nilai /r diperoleh dengan perhitungan koefisien atenuasi linier (μ) dan densitas massa (r) dari hasil pengukuran. Akibatnya, bahan ekuivalen jaringan memiliki nilai /r pada tegangan 70 kVp ( = 39,36 keV) untuk lemak 0,205 cm2/g; otot 0,232 cm2/g; materi putih otak 0,225 cm2/g; otak abu-abumateri 0,229 cm2/g; dan hati 0,253 cm2/g dengan kesalahan literatur masing-masing jaringan sebesar 15,7%; 15,6%; 18,8%; 17,4%; dan 8,4%; serta pada tegangan 82 kVp ( = 57,82 keV) untuk lemak 0,163 cm2/g; otot 0,187 cm2/g; materi putih otak 0,179 cm2/g; materi abu-abu otak 0,170 cm2/g; dan hati 0,185 cm2/g dengan kesalahan literatur masing-masing jaringan sebesar 18,6%; 10,5%; 15,1%; 18,9%; dan 11,9%. Secara keseluruhan, bahan ekuivalen jaringan dari pengujian memiliki nilai /r yang lebih rendah dan tidak sangat dekat dengan nilai /r jaringan berdasarkan referensi.

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In this study, several types of wax (gondorukem, cecek, beeswax, paraffin) and carbon were used as constituents of tissue equivalent phantom material. Body tissues that are the scope of research are fat, muscle, liver, and white matter and gray matter in the brain. The feasibility study of the material was carried out with the HU test. values ​​using a CT scan with a low voltage of 80 kVp and a high of 130 kVp, and testing the attenuation coefficient using an x-ray machine with a voltage of 70 kVp and on standard file conditions RQA 5 with a voltage of 82 kVp. From the results of the HU value test, the composition and comparison of the ingredients for the phantom material are obtained, namely the equivalent of fat [10 (cecek) : 10 (carbon) : 80 (paraffin)], muscle [10 (cecek) : 10 (carbon) : 80 (gondorukem) )], liver [60 (cecek) : 40 (rice flour)], white brain [16 (cecek) : 16 (carbon) : 68 (gondorukem)], and brain gray matter [20 (cecek) : 20 ( carbon): 60 (gondorukem)]. In testing the mass attenuation coefficient, the value of /r is obtained by calculating the linear attenuation coefficient (μ) and mass density (r) from the measurement results. Consequently, the tissue equivalent material has a value of /r at a voltage of 70 kVp (= 39.36 keV) for 0.205 cm2/g fat; muscle 0.232 cm2/g; brain white matter 0.225 cm2/g; gray brain material 0.229 cm2/g; and liver 0.253 cm2/g with a literature error of 15.7% for each tissue; 15.6%; 18.8%; 17.4%; and 8.4%; and at a voltage of 82 kVp (= 57.82 keV) for fat 0.163 cm2/g; muscle 0.187 cm2/g; brain white matter 0.179 cm2/g; brain gray matter 0.170 cm2/g; and liver 0.185 cm2/g with a literature error of 18.6% for each tissue; 10.5%; 15.1%; 18.9%; and 11.9%. Overall, the tissue equivalent material from the test has a lower /r value and is not very close to the network /r value based on the reference"