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"Pengecekan akurasi kualitas citra dalam program kontrol kualitas quality control, QC dapat ditingkatkan dengan penggunaan fantom yang mendekati kondisi realistis pada pemindaian klinis. Penelitian ini ditujukan untuk mengembangkan fantom desain khusus yang terdiri dari material organik ekuivalen-hati dan otot jaringan lunak . Karakterisasi sifat radiologi material ekuivalen jaringan menunjukan bahwa material ekuivalen jaringan lunak otot yang tersusun atas campuran Gondorukem, Malam Cecek, dan tepung beras dengan rasio massa 70/20/10 memiliki CT Number -20.27 0.33 HU, densitas massa 1.055 g/cm3 dan densitas elektron 3.461 1023 e/m3. Material ekuivalen jaringan hati yang tersusun atas campuran Malam Cecek dan tepung beras dengan rasio massa 60/40 memiliki CT Number 74.17 1.48 HU, densitas massa 1.024 g/cm3 dan densitas elektron 3.396 1023 e/m3. Penggunaan fantom desain khusus dalam mengevaluasi kualitas citra PET berdasarkan parameter full-width-half-maximum FWHM resolusi dan signal-to-noise ratio SNR menunjukan bahwa detektabilitas sistem pemindaian PET bergantung terhadap ukuran pixel dan metode rekonstruksi citra yang digunakan. Sistem pencitraan PET/CT Siemens Biograph dengan rekonstruksi True-X dan filter Butterworth menggunakan ukuran pixel 1 x 1 mm2, memberikan ukuran obyek pada citra PET lebih kecil daripada ukuran obyek sebenarnya, kecuali pada obyek 4.02 mm. Sistem pemindaian PET/CT Philips Gemini TOF 16 dengan ukuran pixel 4 x 4 mm2 menunjukan adanya perbesaran ukuran obyek kecil dengan diameter kurang dari 16 mm. Kedua pesawat PET/CT menunjukan bahwa ukuran obyek pada citra cenderung lebih kecil atau mencapai threshold 80 dari ukuran sebenarnya pada obyek berdiameter lebih besar sama dengan 16.30 mm. Sebaliknya, overestimation nilai FWHM terjadi pada obyek berukuran kecil 4.20 mm sebagai akibat dari terjadinya partial volume effect. Studi pengukuran kualitas citra dengan fantom desain khusus ini menunjukan bahwa pemilihan metode rekonstruksi, filter post processing, dan ukuran pixel mempengaruhi resolusi atau detektabilitas dan SNR pada citra PET. Pada akhirnya, fantom desain khusus ini mampu memberikan analisa kualitas.

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The purpose of this research was to develop a phantom for quality control QC of PET CT image quality. The phantom was constructed by tissue equivalent materials which consist six cylindrical hot lesions with diameter of 4.20, 6.20, 8.30, 9,80, 16.30, and 19.00 mm. Wax and rice starch were combined to produce the tissue equivalent materials. The results showed that combination 70 20 10 of gondorukem cecek wax rice starch and 60 40 of cecek wax rice starch yielded liver and muscle surrogate materials respectively. Liver equivalent material LEM was 74.17 1.48 HU, 1.024 g cm3 of mass density, and 3.396 1023 e m3 of electron density. While, muscle equivalent material MEM was 20.27 0.33 HU, 1.055 g cm3 of mass density and 3.461 1023 e m3 of electron density.

Then, the phantom was scanned using two different PET CT scanner to determine the detectability and signal to noise ratio SNR as measure PET CT imaging performance. It showed that the detectability of PET CT scanner was affected by pixel size and reconstruction method for image acquisitions. For Siemens Biograph PET CT scanned using pixel sixe of 1 1 mm2, FWHMs were smaller than the actual size of the hot lesions. Meanwhile, for Philips Gemini PET CT scanned using pixel sixe of 4 4 mm2, FWHMs were larger than the actual size of the hot lesions.

For both PET CT scanner, ratio of FWHM actual size reached the threshold of 80 at object diameter ge 16.30 mm. In contrast, overestimation of FWHM occurred at smaller object diameter 4.20 mm significantly caused by the partial volume effect. The study also indicated that image reconstructions, post processing smoothing filter, and pixel size may give impact to the detectability and SNR performed by a PET CT system. It was concluded that the phantom could be used to analyze the image quality performance in PET CT imaging."

"X-ray computed tomography (CT) has been playing an important role in current medical practice for diagnostic procedure. Beside its delicate technology, the 'hidden' software of CT image reconstruction has contributed almost half of total cost of a CT-scanner unit. Since Algebraic Reconstruction Technique (ART) is a basic to understand an iterative method of CT image reconstruction algortihm, and since it is difficult to find a clear description of fan beam ART algorithm in university literatures, it is important to develop an own algorithm and to begin a basic systematic research of this iterative method. After a long term of trial and error work, the research had succeded in developing an ART algorithm for third generation CT image reconstruction. By comparing the result of the research with more popular technique like Filtered Back Projection (FBP), the algorithm has been proved applicable to reconstruct a low dimension object matrix (32x32 and 64x64). By the resulted computer program, then basically a simple and low cost third generation CT-scanner can be designed for medical physics or biomedical imaging research. Finding a way of shortening the massive number of iterations process then, will be able to open the possibility of using the software for higher object matrix dimensions."

""The book offers a comprehensive and user-oriented description of the theoretical and technical system fundamentals of computed tomography (CT) for a wide readership, from conventional single-slice acquisitions to volume acquisition with multi-slice and cone-beam spiral CT. It covers in detail all characteristic parameters relevant for image quality and all performance features significant for clinical application. Readers will thus be informed how to use a CT system to an optimum depending on the different diagnostic requirements. This includes a detailed discussion about the dose required and about dose measurements as well as how to reduce dose in CT. All considerations pay special attention to spiral CT and to new developments towards advanced multi-slice and cone-beam CT. For the third edition most of the contents have been updated and latest topics like dual source CT, dual energy CT, flat detector CT and interventional CT have been added. The enclosed CD-ROM again offers copies of all figures in the book and attractive case studies, including many examples from the most recent 64-slice acquisitions, and interactive exercises for image viewing and manipulation. This book is intended for all those who work daily, regularly or even only occasionally with CT: physicians, radiographers, engineers, technicians and physicists. A glossary describes all the important technical terms in alphabetical order. The enclosed DVD again offers attractive case studies, including many examples from the most recent 64-slice acquisitions, and interactive exercises for image viewing and manipulation"--Back cover."

"Computed Tomography (CT) Scanner merupakan alat pencitraan diagnostik yang memberikan informasi citra medis untuk menunjang pengobatan pasien, namun tanpa disadari pemanfaatan radiasinya dapat menimbulkan efek negatif pada organ sensitif sekitar. Penelitian ini dilakukan untuk mengukur dosis organ sensitif (mata, tiroid, dan payudara) menggunakan fantom Rando pada CT Scanner area thorax. Untuk memudahkan penelitian ini, TLD rod 100 digunakan sebagai dosimeter, dimana kV dan pitch dijadikan sebagai variasi parameter penelitian. Hasil menunjukkan bahwa nilai paparan dosis tertinggi pada tiap kualitas berkas berturut-turut dari 80, 120, dan 140 kV yaitu payudara kanan (1,72±0,34 mGy), tiroid kanan (6,25±0,16 mGy), dan payudara kiri (10,78±0,76 mGy). Pada variasi pitch nilai paparan dosis tertinggi secara berturut-turut dari 4, 6, dan 8 yaitu payudara kiri (6,19±0,02 mGy), tiroid kanan (6,25±0,16 mGy), dan payudara kanan (5,08±0,85 mGy). Dapat disimpulkan bahwa nilai dosis payudara pada CT Thorax lebih tinggi dibandingkan dengan mamografi, namun keduanya tidak melebihi nilai batas dosis yang ditetapkan International Commission on Radiological Protection (ICRP) yaitu 5 Gy.

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Computed Tomography (CT) Scanner is an instrument of medical imaging using radiation to support treatment for patient, but the radiation may give a negative effect around sensitive organs. The research meant to measure dose for sensitive organs at thorax area (eyes, thyroid, and breast) using CT Scanner with rando phantom as an object. To ease this experiment, TLD rod 100 used as dosimetry, which kV and pitch as a parameter variation. The result showed that the highest dose for kV variation upon each sequent beam quality from 80, 120, and 140 kV are right breast (1,72±0,34 mGy), right thyroid (6,25±0,16 mGy), and left breast (10,78±0,76 mGy). Towards pitch variation the highest exposure dose value in sequently from 4, 6, and 8 are left breast (6,19±0,02 mGy), right thyroid (6,25±0,16 mGy), and right breast (5,08±0,85 mGy). As a conclusion, the dose on breast from CT Thorax is higher than the one from mammography but both are bellow dose value limit from International Commission on Radiological Protection (ICRP) which is 5 Gy."

"Computed Tomography Dose Index (CTDI) merupakan konsep utama dalam dosimetri CT scan. Berdasarkan rekomendasi IAEA di TRS 457, CTDI dapat diukur di udara dan di fantom khusus CTDI. Ukuran dan massa fantom cukup besar sehingga akan menyulitkan dalam mobilisasi. Dalam penelitian ini dilakukan pengukuran CTDI untuk mengetahui faktor fantom pesawat Siemens Sensation 64. Faktor fantom adalah perbandingan CTDIw terhadap CTDIair. Fantom yang digunakan adalah fantom berbahan polymethil methacrylic (PMMA) berdiameter 16 cm sebagai fantom kepala dan 32 cm sebagai fantom tubuh. Detektor yang digunakan adalah Xi CT Platinum dan Xi Base Unit sebagai elektrometer. Estimasi dosis efektif dihitung berdasarkan nilai CTDIair pengukuran yang dikoreksi dengan perangkat lunak ImPACT CT Dosimetry Patient Calculator version 1.0.4. Nilai faktor fantom yang diperoleh untuk fantom kepala dan tubuh secara berturut-turut ialah 0.702 dan 0.357. Estimasi dosis efektif satu fase (rata-rata ± deviasi standar) ialah: kepala rutin 2.01 ± 0.11 mSv, kepala trauma 2.53 ± 0.16 mSv, thorak 3.4 2 ± 0.79 mSv, abdomen 5.99 ± 2.16 mSv, dan pelvis 2.12 ± 0.99 mSv. Faktor konversi DLP displai scanner terhadap dosis efektif: kepala rutin 0.0021 mSv/mGy.cm, kepala trauma 0.0022 mGy.cm, thorak 0.0182 mSv/mGy.cm, abdomen 0.0151 mSv/mGy.cm, dan pelvis 0.0118 mSv/mGy.cm.

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Computed Tomography Dose Index (CTDI) is primary dosimetric concept in CT scan. Based on IAEA TRS 457 recommendation, CTDI can be measured free in air and by using phantom. Phantom size and mass are huge, thus it will complicate the mobilization. This research conducted CTDI measurement to find out the Siemens Sensation 64 phantom factor. Phantom factor is a ratio between CTDIw over CTDIair. A Polymethyl Methacrylic (PMMA) phantom was used in this research, which has 16 cm of diameter for head phantom and 32 cm of diameter for body phantom. The Xi CT Platinum detector was used in this research and Xi base unit is as an electrometer. The estimation of effective dose was calculated using CTDIair value and ImPACT CT Dosimetry Patient Calculator version 1.0.4. In this research was found out that the phantom factors are 0.702 for head phantom and 0.357 for body phantom. The estimation of effective dose for one phase (mean ± standard deviation): head routine 2.01 ± 0.11 mSv, head trauma 2.53 ± 0.16 mSv, thorax 3.4 2 ± 0.79 mSv, abdomen 5.99 ± 2.16 mSv, and pelvis 2.12 ± 0.99 mSv. DLP on scanner display to effective dose conversion factors: head routine 0.0021 mSv/mGy.cm, head trauma 0.0022 mSv/mGy.cm, thorax 0.0182 mSv/mGy.cm, abdomen 0.0151 mSv/mGy.cm, and pelvis 0.0118 mSv/mGy.cm."

"This unique, findings-oriented guide to computed tomography is organized to reflect the way radiologists really work: progressing from general impressions to definitive diagnoses. In nearly 1000 high-quality scabs, the radiologist will find CT findings depicting frequently encountered congenital and acquired diseases and disorders. Included in the wide-ranging survey of CT findings are traumatic injuries; congenital anomalies; and infectious, inflammatory, neoplastic, and degenerative disease processes. For convenience, these are grouped anatomically by brain, head and neck, spine, musculoskeletal system, chest, abdomen, and pelvis. In addition, the book's extensive index systematically cross-references diseases and CT findings, providing even greater accessibility to key information"--Provided by publisher."

"Modalitas pencitraan yang sering digunakan pada diagnosis kanker kandung kemih adalah Computed Tomography (CT). Informasi dari hasil pembacaan citra CT diharapkan berupa volume pada jaringan abnormal yang berguna untuk penentuan tindakan medis selanjutnya. Namun karena pada setiap slice citra memiliki ukuran, bentuk dan lokasi kanker kandung kemih yang berbeda-beda, maka penentuan volume menjadi tidak mudah. Oleh karena itu untuk meningkatkan keakuratan dan konsistensi penentuan diagnosa dan volume jaringan abnormalnya maka diperlukan bantuan Computer-Aided Diagnosis (CAD). CAD dapat dikembangkan menjadi perhitungan volume jaringan abnormal berdasarkan segmentasi dan klasifikasi citra. Pada penelitian ini, sistem CAD yang dikembangkan menggunakan metode segmentasi, fitur ekstrasi berbasis Gray Level Co-Occurrence Matrix (GLCM) dan klasifikasi citra normal dan abnormal menggunakan k-Nearest Neighbors (kNN). Data yang digunakan pada penelitian ini adalah 300 citra CT kandung kemih dari Rumah Sakit Kanker Dharmais, terdiri dari 100 citra normal dan 200 citra abnormal dengan 210 citra digunakan sebagai data pelatihan dan 90 citra digunakan sebagai data pengujian. Hasil performa sistem klasifikasi citra berupa akurasi sebesar 94,28% untuk data pelatihan dan 91,22% untuk data pengujian. Pada penelitian ini dilakukan kalkulasi volume jaringan abnormal kandung kemih terhadap 6 pasien dan hasilnya diperoleh volume terkecil 4,15 cm³ dan terbesar 77,40 cm³. Selain itu ditunjukkan pula volume jaringan abnormal terkecil yang dapat dideteksi adalah sekitar 0,03 cm³.

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The most frequency using in the diagnosis of bladder cancer is computed tomography (CT). Information from CT image reading is expected to be in in the form abnormal tissue volume that is useful for determining the next treatment. However, the resulting image slices has a different size, shape and location of bladder cancer, determining the volume is not easy. Therefore, to improve the accuracy and consistency of reading medical images and abnormal tissue volume, Computer-Aided Diagnosis (CAD) can be assisted. CAD can be developed into abnormal tissue volume calculations based on image segmentation and classification. In this study, the CAD system was developed using preprocessing, segmentation, feature extraction based on Gray Level Co-Occurrence Matrix (GLCM) and normal and abnormal image classification using k-Nearest Neighbors (kNN). The data used in this study are 300 bladder CT images from Dharmais National Cancer Hospital, consisting of 100 normal images and 200 abnormal images. 210 images are used as training data, and 90 images are used as testing data. The results of CAD system performance in this study are in the form of the accuracy of 94.28% for training data and 91.22% for testing data. In this study, the volume of abnormal bladder tissue was calculated for 6 patients, and the results obtained the smallest volume is 4.15 cm³ and the largest 77.40 cm³. In addition, it is also shown that the smallest abnormal tissue slice in slice volume that can be detected is about 0.03 cm³."

"Citra Cone Beam CT (CBCT) sangat berperan dalam menentukan keberhasilan verifikasi posisi pasien radioterapi, oleh karena itu jaminan kualitas sistem CBCT sangat diperlukan. Percobaan ini dilakukan dengan menggunakan pesawat Linear accelerator yang dilengkapi dengan CBCT dan CT Simulator GE Bright Speed Edge. Fantom Catphan® 600 dan CBCT Electron DensityTM digunakan untuk menilai kualitas dari citra CBCT dan linearitas CT Number. Sesuai dengan uji kualitas, citra pada CBCT hanya dapat membedakan kontras rendah dan kontras tinggi (udara, jaringan dan tulang). Hasil uji ketebalan slice menunjukkan nilai yang didapat masih dalam batas toleransi ±0.5 mm. Pada uji kontras rendah bagian supra-slice untuk target kontras 1%, 0.5%, dan 0.3% nilai konstantanya sebesar 3, 2.5, dan 4.5, sedangkan pada bagian sub-slice untuk target kontras jarak 7, 5, dan 3 mm memiliki nilai konstanta 5 mm. Hasil pengujian resolusi tinggi pada CBCT dan CT Simulator adalah 3 lp/cm dan 7 lp/cm. Hasil pengujian uniformitas pada CBCT tidak memenuhi standar dari batas toleransi rata-rata CT Number tepi dan tengah kurang dari 5 HU, dan nilai setiap titik tepi dan tengah ±2 HU.

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Cone Beam Computed Tomography (CBCT) image is very important in verification of patient positioning in the treatment couch radiotherapy machine so quality control of the system is required. The experiment was performed using the Linear accelerator with equipped with CBCT and CT simulator GE Bright Speed Edge. Catphan® 600 and CBCT Electron DensityTM phantom was used to evaluate the quality of CBCT and CT Number linearity. According to the image quality test, the CBCT image only be able to distinguish low contrast and high contras for air, tissue and bone.

Quantitavely, the slice thickness was in tolerance limit ±0.5 mm, low contrast with constant value of 3, 2.5, dan 4.5 for supra-slice contrast targets 1%, 0.5%, dan 0.3% whereas sub-slice targets axis lenghts for 3, 5, and 7 mm with constant value of 5 mm, the high resolution appear in 3 lp/cm and 7 lp/cm for CBCT and CT simulator, respectively. On the one hand, CBCT uniformity was out of tolerance limit with average CT number edge and central less than 5 HU, and ±2 HU for the edge and center point."

"Perkiraan nilai dosis yang diterima pasien ( CTDI ) yang langsung ditampilkan pada monitor CT setiap selesai pemeriksaan akan diketahui ketepatan nilainya dengan pengukuran langsung menggunakan pencil ion chamber dan pengukuran tidak langsung menggunakan TLD (Thermolumescence Dosimeter ) yang ditempatkan pada objek phantom dan dibandingkan dengan nilai dosis referensi yang telah ditetapkan, sehingga diharapkan mendapatkan informasi nilai dosis yang sebenarnya.Analisis variasi parameter kV, mAs, dan pitch untuk menentukan berapa rentang nilai parameter optimum untuk mendapatkan nilai dosis pasien (CTDI/mAs) yang minimum namun tidak mengesampingkan kualitas pencitraan hasil CT. Scan yang baik guna menunjang diagnosa, pengukuran langsung maupun tidak langsung dengan menggunakan fantom kepala dan perut.Pengukuran tidak langsung dengan menggunakan TLD (Thermolumescence Dosimeter ) pada menunjukan hasil yang tidak jauh berbeda dengan pengukuran langsung dengan menggunakan pencil ion chamber, dapat ditunjukkan dengan hubungan sifat kelinearan antara pitch dan dosis (CTDI/mAs).

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An estimation dose (CTDI) received by the patient which is directly displayed on the CT monitor on every examination will be able to known it?s precisien by direct measurement using pencil ion chamber and the indirect measurement using TLD placed on the object (phantom) and compared with the value of dose reference, so the real dose rate will be known.

The variant analysis of kV, mAs and pitch parameters to justify the range of optimal parameter value, it is used to get the minimum patient dose rate (CTDI/mAs) while the image quality for supporting the diagnose still on the right value, directly or not directly using head and abdomen phantom.

Indirect measurement using TLD show unsignificant result if compared with the ion chamber. This value is shown by a relative variant parameter using stright pitch and dose ( CTDI/mAs)."