Comparison of Gamma Index Passing Rate in Several Treatment Planning System Algorithms

The verification of dose calculation algorithm in a new Treatment Planning System (TPS) can be evaluated by comparing the passing rate of the gamma index analysis of the evaluated algorithm and the clinically implemented algorithms. In the present investigation, the gamma index passing rates was investigated as the reference data in the verification of the new three-dimensional TPS. The algorithms which are used in this study are Pencil Beam Convolution (PBC) version 11.0.31 and Anisotropic Analytical Algorithm (AAA) version 11.0.31 in Eclipse v.11 TPS, and Fast Convolution (FC), Adaptive Convolution (AC), and Collapsed-Cone Convolution (CCC) in Pinnacle3 v.7.6c TPS. The 6 MV X-ray beam configurations were varied in the depth of measurement points, field sizes, source-to-surface distances, and wedge angles. The dose measurement was done using MatriXX Evolution and PTW 2D-array seven29. Then, OmniPro ImRT and Verisoft 3.1 software were chosen to analyze the gamma index from varied gamma criteria (3 %/3mm, 2 %/3mm, 3 %/2mm, and 2 %/2mm). Overall, the passing rate of AAA is the highest rate obtained of all algorithms. For gamma criterion of 2 %/2mm, the passing rate of AAA was 93.18 % ± 7.21 %, the passing rate of PBC was 89.76 % ± 7.21 %, and the passing rate of convolution algorithms was 76.84 % ± 11.10 %

Dose Planning Evaluation of Intensity-Modulated Proton Therapy (IMPT) Technique Based on In-House Dynamic Thorax Phantom

One of the drawbacks of the Intensity Modulated Radiation Therapy (IMRT) technique is that the absorbed dose in healthy tissue is relatively high. Proton beam has characteristics that can compensate for these drawbacks. The Bragg peak characteristic of a proton beam allows the administration of high radiation doses to the target organ only. Non-Small Cell Lung Cancer (NSCLC) cases are located in the vicinity of many vital organs, so radiation doses that exceed a certain limit will have a significant impact on these organs. Proton is a heavy particle that exhibits interaction patterns with tissue heterogeneity that differ from that of photon. This study aims to determine the distribution of proton beam planning doses in the NSCLC cases with the Intensity Modulated Proton Therapy (IMPT) technique and compare its effectiveness with the IMRT technique. Treatment planning was done by using TPS Eclipse on the water phantom and on the in-house thorax dynamic phantom. The water phantom planning parameters used are one field at 0° and three fields at 45°, 135°, and 225°. In this study, a single, sum, and multiple field techniques on the in-house thorax dynamic phantom were used. The evaluation was performed by calculating Conformity Index (CI), Homogeneity Index (HI), and Gradient Index (GI) parameters for each treatment planning. As a result, a bit of difference in the CI the HI values are shown between IMPT and IMRT planning. The GI values of IMPT planning are in the range between 4.15-4.53, while the GI value of IMRT is 7.89. The histogram results of the planar dose distribution show that the IMPT treatment planning provides fewer off-target organ doses than the IMRT planning. Evaluation was also carried out on the    IMPT treatment planning of target organs in five areas of interest and four OAR positions. The evaluation results were then compared with the IMRT measurement data. As a result, the value of the point doses at the target organ      did not differ significantly. However, the absorbed dose with the IMPT technique at four OAR positions is nearly zero, which had a large difference compared to the IMRT technique

Pengaruh Ketidakhomogenan Medium Pada Radioterapi

Telah dilakukan pengukuran Percentage Depth Dose (PDD) pada medium homogen dan nonhomogen dengan menggunakan bilik ionisasi plan paralel Markus. Phantom homogen dibuat dari susunan lapisan akrilik setebal 30 cm, dan phantom nonhomogen dibuat dengan menyisipkan lapisan gabus ekivalen paru-paru setebal 4 cm yang dimasukkan ke dalam susunan akrilik. Penyinaran dilakukan dengan sinar-X 6 MV dan 10 MV yang diproduksi oleh LINAC Varian 2100C. Perbedaan prosentase dosis kedalaman (PDD) pada medium homogen dan nonhomogen rata-rata sebesar 4,3% pada sinar-X 6 MV dan 3,7% pada sinar-X 10 MV. Pemberian gabus pada akrilik mengakibatkan peningkatan dosis sampai 11,7% pada sinar-X 6 MV dan 10,2% pada sinar-X 10 MV. Faktor koreksi yang dihasilkan sebagai akibat adanya material ekivalen paru-paru/gabus mencapai 1,19 pada sinar-X 6 MV dan 1,15 pada sinar-X 10 MV

Perbandingan Verifikasi Akurasi Posisi Pasien Radioterapi Secara Manual Dan Semiotomatis Berbasis Citra DRR/EPID

Radiotherapy is one of common treatment modality for Nasopharyngeal Cancer. The development of intensity modulated radiotherapy (IMRT technique) gives satisfactory results in the nasopharyngeal cancer treatment, both clinically and dosimetry. IMRT can reduce the effects of acute and chronic, with a maximum dose coverage to the tumor and minimal dose to the organ or normal tissue surrounding target value. The purpose of this study is to compare theaccuracy of patient positioning verification of Nasopharyngeal Cancer IMRT with DRR / EPID image registration. Retrospective data analysis of the AP and Lateral projections DRR and EPID images 35 patients (140 images) were then manually verified by simulative applied fusion semiautomatic with FIJI program. FIJI program improved the image quality of the DRR and EPID to facilitate the image registration. Results of this study shows no statistically significantdifference between the manual verification and semiautomatic fusion method of nasopharyngeal cancer patients, but there is a tendency that the semiautomatic method with FIJI program provides verification geometry radiotherapy better a result than manual methods

Verifikasi Dosimetri Teknik Stereotactic Body Radiotherapy (SBRT) Metastasis Tulang: Studi Kasus Menggunakan Fantom Homogen dan Inhomogen

Kanker menyebabkan 13% dari total semua kasus penyebab kematian, dan matastasis tulang adalah komplikasi umum dari kanker yang terjadi diatas 40% pada pasien onkologi. Sekitar 70% metastasis akan melibatkan tulang belakang. Stereotactic body radiotherapy (SBRT) adalah salah satu teknik yang dapat menangani metastasis tulang karena dapat memberikan dosis radiasi tinggi pada volume kecil dengan margin yang sangat rapat. Dalam perencanaan radioterapi untuk foton energi tinggi sering tidak sesuai dalam memperkirakan distribusi dosis dengan keberadaan material tidak homogen. Oleh karena itu dibandingkan hasil dosis pada fantom homogen (CIRS Model 002 H9K) dengan fantom inhomogen (CIRS Model 002 LFC) menggunakan tiga dosimeter, yaitu mikrochamber exradin A16, film gafchromic EBT3, dan TLD LiF: Mg, Ti rods. Hasil yang didapatkan dari pengukuran kedua fantom membuktikan bahwa film gafchromic EBT3 merupakan dosimeter terbaik dalam pengukuran dosis pada lapangan kecil dengan masing-masing deskripansi -0,30% pada fantom homogen dan -1,57% pada fantom inhomogen. Mikrochamber juga memperlihatkan kemampuannya dengan mendapatkan deskripansi tidak begitu jauh dengan film gafchromic EBT3 yaitu -0,52% pada fantom homogen dan -3,87% pada fantom inhomogen. Sedangkan menggunakan TLD LiF:Mg, Ti rods masing-masing deskripansinya -11,96% dan -13,88% pada fantom homogen dan inhomogen

Dose Evaluation of Head and Neck Cancer IMRT Treatment Planning Based on Gamma Index Analysis of Varian Halcyon 2.0 Linac

Varian Halcyon 2.0 linear accelerator was launched and became available for clinical use in 2018. Therefore, it is necessary to evaluate the accuracy of exit fluence of the Halcyon 2.0 for quality assurance (QA) of head and neck cancer treatment planning, pretreatment, and treatment. The accuracy of the exit fluence for twenty treatment plannings has been evaluated by conducting gamma analysis for QA pretreatment and treatment in each field and composite field by using criteria for gamma index 3 %/3 mm and 2 %/2 mm. The QA pretreatment results are in the average value for each criterion for each field and composite fields on actual gantry angle and null gantry angle with gamma passing rate (GPR) of over 99 % (range 99.78 %-99.95 %) The total treatments consisted of 2717 fractions. The analysis results of GPR for fields were 99.32 % and 97.74 % for gamma indexes of 3 %/3 mm and 2 %/2 mm, respectively. In addition, the analysis results of GPR for composites were 95.46 % and 81.38 % for gamma indexes of 3 %/3 mm and 2 %/2 mm, respectively. Based on this result, the average GPRs of QA pretreatment are ≈ 99 % of the total pixels. This means the prediction dose of Varian Halcyon 2.0 is accurate. The average GPRs of treatment is nearly  90 %, showing that Varian Halcyon 2.0 is effective for creating treatment plans for complex cases

Occupational Dose Estimation with Field Size, Position and C-Arm Gantry Tilt Variations During Interventional Cardiology Procedures

In Interventional Cardiology, dose received by the patient is relatively higher, while the occupational would receive scattered radiation dose whose quality is relatively lower. However, the occupational received accumulative doses of all cardiovascular procedures were done over the years. Therefore, the purpose of this paper will focus to estimate the distribution of scattered dose to occupational without any protective shielding in the Cath Lab. The scattered dose rate was measured by using survey detector of Unfors Xi. The detector was placed at 6 different positions around the phantom. Each measurement position has eleven points from 25 to 175 cm above the floor with increment of 15 cm as the illustration of partial height of occupational organ. Experimentally a Rando phantom was irradiated by automatic pulsed fluoroscopy with condition varies in the range of 88-93 kV and 5.7-9.4 mA depend on gantry tilt and field size. The Philips C-arm gantry tilt was varied at 0o PA projection, 20o and 30o Caudal, 20o and 30o Cranial, and 40o and 50o Left Anterior Oblique, and also Flat Panel Detector (FPD) was varied at 20 x 20 and 25 x 25 cm2. Generally, the greatest dose rate was known at level corresponding to the waist (100 cm) of occupational and the lowest at head areas (175 cm) of occupational which is 2.49 mGv/h and 0.02 mGy/h, respectively. The given data showed that the scattered fractions are in the range of 0.001-0.060% from its primary dose at isocenter. The scattered doses tend to increase with gantry tilt for all positions. Increasing field size of FPD will decreased the scattered fraction from its dose at isocenter, and also it affects the scattered dose rate

Evaluasi Dosis Glandular Dalam Pemeriksaan Mammografi

Mean glandular Dose (MGD) during mammography has been determined for 49 patients using TLD. MGD numbers has been derived from the measured ESD (Entrance Surface Dose) by multiplicating ESD with converted Dp, (ESD with average glandular dose per unit exposure conversion factor) incorporating the glandular percentage to adipose percentage. Dgn data were obtained from Boone's Monte Carlo calculation and generally is a function of HVL values and breast thickness. The glandular percentage to adipose were obtained using Nooriah Djamal's methods of mammography film analysis Both 0% glandular Dgn for adipose contribution and 100% glandular DSu for glandular contribution were then obtained from Boone's table. Average Entrance Surface Dose (ESD) for 49 patients were found to be 7.6 ('bl 3.9) mGy. The average MGD for 49 patients were found to be 1.818 (bl 0.615) mGy. These values were generally below the recommended FDA (Food and Drug Administration) limit of 3 mGy

Keperawatan Jiwa : terapi aktivitas kelompok

ix, 126 hlm.; 20,5 x 14 c