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"Telah dilakukan penelitian untuk menentukan karakteristik dasar dari scanner yang digunakan untuk dosimetri film radiochromic EBT2. Dalam penelitian ini digunakan scanner Vidar DosimetryPro Advantage dan Epson Perfection V700. Pengujian yang dilakukan meliputi uji konsistensi scanner, uji variasi film to film, uji uniformitas scanner, uji efek orientasi film, uji suhu ruang penyimpanan film, uji fading film dan uji noise film/scanner. Scanner diuji menggunakan film EBT2 yang telah dipapar radiasi menggunakan Linac dengan modalitas foton 6 MV. Film mempunyai 8 buah lapangan berukuran 3 cm x 3 cm dengan dosis dari 31,31 - 250,48 cGy. Software yang digunakan untuk menganalisa hasil bacaan scanner adalah ImageJ dan FilmQA Pro. Dari hasil pengujian didapatkan konsistensi Vidar mode Logarithmic lebih baik dengan standar deviasi (SD) kurang dari 0,06%, sedangkan standar deviasi Epson mencapai 0,40%. Uniformitas Vidar juga lebih baik dengan SD kurang dari 0,76% dibandingkan Epson yang mencapai 1,16%. Orientasi film cukup berpengaruh terhadap hasil bacaan, terutama pada Epson, sehingga orientasi film harus konstan selama pemindaian. Pengujian noise film/scanner menunjukkan bahwa Epson menghasilkan noise yang lebih kecil sebesar 0,10% dibandingkan Vidar yang menghasilkan 0,33%. Performa Vidar secara keseluruhan lebih bagus daripada Epson terutama saat red channel saja yang dianalisa.

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Has been done measurement of basic characteristic of Vidar DosimetryPro Advantage and Epson Perfection V700 scanner based on radiochromic EBT2 film dosimetry. The tests were consist of the consistency test, film to film variation test, scanner uniformity test, effect of film orientation test, room storage temperature test, film fading test and scanner noise test. The scanners performance were tested using The scanners performance were tested using EBT2 with eight separated 3 x 3 cm2 fileds to doses ranging from 31.31 - 250.48 cGy which was irradiated using photon beam of Linac 6 MV. For evaluation, ImageJ and FilmQA Pro were used. The performance of Vidar scanner is higher in consistency and unifromity with standard deviation of measurement 0.06% and 0.76% compare with with Epson scanner with standard deviation of 0,40% and 1.16%. The film orientation effect made a big different result especially in Epson that reached 10.65% differences between portrait and landscape orientation. The scanner noise was small: 0.10% in Epson and 0.33% in Vidar. The overall measurements of Vidar was better than Epson, especially because only red channel that was analyzed."

"[ABSTRAKFilm gafchromic EBT2 dan EBT3 cocok digunakan untuk jaminan kualitas (QA) pada treatment planning systems (TPS) dan linear accelerator (LINAC) serta verifikasi radioterapi teknik IMRT dan VMAT. Namun generasi selanjutnya dari film gafchromic EBT yaitu EBT2 dan EBT3 ketika dilakukan scanning (pemindaian) menggunakan scanner flatbed masih terdapat artefak geometris yang dahulunya juga ditemukan pada film EBT sehingga memerlukan penanggulangan dan koreksi yang sesuai. Pada penelitian ini menggunakan scanner flatbed Epson expression 10000XL, Epson perfection V700 dan Mikrotek 1000XL plus yang dapat menangkap warna dengan rinci dan presisi. Perangkat lunak yang digunakan dalam koreksi ini adalah FilmQA Pro 2015. Hasil yang diperoleh yaitu Koefisien A dan B diterapkan untuk variasi posisi lateral terhadap nilai tanggapan di lokasi yang bersamaan, sehingga pengkoreksian tanggapan artifak lateral dapat dilakukan. Pada dosis maksimum nilai koreksinya <0,5% dan pada kasus <0.2%. Pada pengukuran ulang untuk setiap film, standar deviasi yang diperoleh untuk setiap film sekitar 0.19%. Pengujian dosimetri channel tunggal (merah) sebelum dan sesudah koreksi pada kasus IMRT didapatkan hampir 91% dari piksel memenuhi 3% / 3mm kriteria gamma keseluruhan dengan ambang batas dosis > 10%. Untuk pengujian kasus VMAT, film di scan dengan posisi di pusat scanner dan posisi ektrim tepi scanner, maka pengukuran di channel warna merah 4% lebih tinggi dibandingkan channel warna hijau dan biru. Rata-rata konsistensi pengukuran dosis selama daerah terkena dosis > 100 cGy adalah sekitar 21,8 cGy dan di daerah yang paling dekat dengan tepi scan window sekitar 10 mm dengan perbedaan dosis 35 cGy. Setelah dilakukan koreksi, rata-rata konsistensi dosis pada tiga channel di sekitar daerah terpapar sekitar 5,1 cGy. Perbedaan dosis antar channel sekitar 9 cGy. Hasil ini menunjukkan koreksi respon artefak lateral memang perlu dilakukan. Respon yang diukur tergantung pada posisi film pada pemindai dan dosis yang diberikan. Pengukuran pada channel warna merah menunjukkan sensitivitas yang lebih besar pada dosis rendah, sedangkan respon pada channel hijau atau biru memberikan perpanjangan jangkauan dinamis dari film ke dosis tinggi. Metode triple-channel dosimetri telah terbukti memiliki keuntungan signifikan atas single channel dosimetry dengan akurasi dosimetri yang baik.

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ABSTRACT

The film of gafchromic EBT2 and EBT3 are appropriate for quality assurance (QA) to the radiotherapy technics verification of IMRT and VMAT. In the next generations of EBT which are EBT2 and EBT3, are still attained the geometrical artifacts once scanning by flatbed scanner which is used to be found on EBT film in order to need an overcome ways and an appropriate correction. This research used a flatbed scanner EPSON expression 10000XL, EPSON perfection V700 and Microtech 1000XL plus and FilmQA Pro 2015 as a software for correcting it. The result shows that coefficient A and B were applied for lateral correction artifacts responses can be made. On the maximum dose, it has correction value as much as <0,5% and in case was <0.2%. The deviation standard was approximately 0,19% on re-measure for each film. Prior to the dosimetry measurement of single channel (red) and subsequent to the correction IMRT has got almost 91% of pixel which met with gamma criteria, 3% / 3mm, with dose threshold 10% TH. In the measurement of VMAT‟s case, film scanned on the center of scanner and the extreme position of the scanner edge. Thus, measurement in the red channel was 4% higher than green and blue channel. The average of dose measurement consistency during area exposed to doses > 100 cGy is approximately 21,8 cGy and the closest area with the edge of scan window is around 10 mm at difference doses 35 cGy. After correction, the average of doses consistency was 5,1 cGy on the three channel where exposed. The distinction of doses was approximately 9 cGy among channels. This result stated that the correction of artifacts lateral response is needed to carry on. The method of triple-channel dosimetry has the significant advantage on single-channel dosimetry with a good consistency. Through escalation dose and variation of lateral position, the distinct response would be increased on single-channel which is red channel. The measurement on red channel reveals the highest sensitivity on the slight dose. Whereas, a green or blue channel response provides a dynamic range extension of film to a high dose. Thus, the method of dosimetry triple-channel has the significant contribution of single-channel evidently with a good dosimetric accuracy., The film of gafchromic EBT2 and EBT3 are appropriate for quality assurance (QA) to the radiotherapy technics verification of IMRT and VMAT. In the next generations of EBT which are EBT2 and EBT3, are still attained the geometrical artifacts once scanning by flatbed scanner which is used to be found on EBT film in order to need an overcome ways and an appropriate correction. This research used a flatbed scanner EPSON expression 10000XL, EPSON perfection V700 and Microtech 1000XL plus and FilmQA Pro 2015 as a software for correcting it. The result shows that coefficient A and B were applied for lateral correction artifacts responses can be made. On the maximum dose, it has correction value as much as <0,5% and in case was <0.2%. The deviation standard was approximately 0,19% on re-measure for each film. Prior to the dosimetry measurement of single channel (red) and subsequent to the correction IMRT has got almost 91% of pixel which met with gamma criteria, 3% / 3mm, with dose threshold 10% TH. In the measurement of VMAT‟s case, film scanned on the center of scanner and the extreme position of the scanner edge. Thus, measurement in the red channel was 4% higher than green and blue channel. The average of dose measurement consistency during area exposed to doses > 100 cGy is approximately 21,8 cGy and the closest area with the edge of scan window is around 10 mm at difference doses 35 cGy. After correction, the average of doses consistency was 5,1 cGy on the three channel where exposed. The distinction of doses was approximately 9 cGy among channels. This result stated that the correction of artifacts lateral response is needed to carry on. The method of triple-channel dosimetry has the significant advantage on single-channel dosimetry with a good consistency. Through escalation dose and variation of lateral position, the distinct response would be increased on single-channel which is red channel. The measurement on red channel reveals the highest sensitivity on the slight dose. Whereas, a green or blue channel response provides a dynamic range extension of film to a high dose. Thus, the method of dosimetry triple-channel has the significant contribution of single-channel evidently with a good dosimetric accuracy.]"