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Abstrak :
Penelitian ini bertujuan untuk mengetahui karakteristik material organik pengganti fantom polymethyl methacrylate (PMMA) dan fantom air dengan parameter backscatter factor (BSF) dan koefisien atenuasi linear (m). Pengukuran BSF dan m dilakukan menggunakan mobile X-Ray dengan faktor eksposi 40-120 kV dengan dua puluh variasi kualitas berkas pada tiga luas lapangan yang berbeda (untuk pengukuran BSF). Hasilnya, fantom organik memiliki nilai BSF yang mendekati fantom standar dengan deviasi < 8% dan < 10%, berturut-turut untuk fantom ekuivalen air dan PMMA. Sementara nilai m untuk fantom-ekuivalen air pada tegangan > 60 kV memiliki tingkat kesalahan < 15% untuk fantom ekuivalen air dan < 18% untuk fantom ekuivalen PMMA. ...... This research aims to verify physical characteristics of water and polymethyl methacrylate (PMMA)-equivalent phantom made of organic materials in terms of its interaction with diagnostic-range radiation. Backscatter factor (BSF) and linear attenuation coefficient (m) were selected as test parameters. Measurement of BSF and m has been performed using mobile x-ray beam with the exposure factor of 40 to 120 kV. For BSF, measurement has been carried out using twenty different beam qualities in three different field sizes. The final results show similarity between water equivalent-phantom and the literature with the error below 8% and below 10% for the PMMA equivalent-phantom. The results of m measurement for water equivalent phantom in the beam voltage above 60 kV shows error below 15% compared to standard water phantom. On the other hand, PMMA quivalent-phantom shows an error below 18%.

Abstrak :
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-abu materi 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. ......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

Abstrak :
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.