scholarly journals Reference photon dosimetry data: A preliminary study of in-air off-axis factor, percentage depth dose, and output factor of the Siemens Primus linear accelerator

2003 ◽  
Vol 4 (4) ◽  
pp. 300 ◽  
Author(s):  
S. H. Cho
Keyword(s):  
Linear Accelerator ◽  
Output Factor ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Photon Dosimetry ◽  
Preliminary Study ◽  
Dosimetry Data

scholarly journals A modified formula for defining tissue phantom ratio of photon beams

2008 ◽  
Vol 33 (3) ◽  
pp. 92-97
Author(s):  
M Jahangir Alam ◽  
KS Rabbani ◽  
GA Zakaria ◽  
SM Akram Hussain ◽  
Adnan Kiber ◽  
...  
Keyword(s):  
Linear Accelerator ◽  
Measured Data ◽  
German Cancer Research ◽  
Photon Beams ◽  
Data Set ◽  
Surface Distance ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Tissue Phantom ◽  
Modified Formula

Tissue phantom ratio (TPR), for square fields of various dimensions has been determined at varying depths in water. The dose in water has been measured at a fixed source-to-surface distance (SSD) of 100 cm and reference depth of 5 cm for 6 MV photon beam of Siemens Linear Accelerator Primus II in German Cancer Research Center (DKFZ), Heidelberg, Germany. A modified formula has been developed to calculate the TPR value for isocentric treatment. The present article describes the conversion of the measured data values into a comprehensive and consistent data set by the modified formula, that gives the TPR from Percentage Depth Dose (PDD) with depth as a function of field sizes from 10 mm x 10 mm up to 300 mm x 300 mm) and depth (from 0 mm to 300 mm).DOI = 10.3329/bmrcb.v33i3.1140Bangladesh Med Res Counc Bull 2007; 33: 92-97

scholarly journals Can Gafchromic EBT3 films effectively characterize small fields of 6 MV unflattened photon beams of Cyberknife system?

2018 ◽  
Vol 24 (4) ◽  
pp. 181-187
Author(s):  
Jerrin Amalraj ◽  
Ramasubramanian Velayudham ◽  
Pichandi Anchineyan
Keyword(s):  
Silicon Detectors ◽  
Photon Beams ◽  
Output Factor ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Gamma Analysis ◽  
Small Fields ◽  
Output Factors ◽  
Dose Measurements ◽  
Dose Difference

Abstract Shielded silicon diodes are commonly employed in commissioning of Cyberknife 6 MV photon beams. This study aims to measure output factors, off centered ratio (OCR), percentage depth dose (PDD) of 6 MV photons using shielded and unshielded diodes and to compare with Gafchromic EBT3 film measurements to investigate whether EBT3 could effectively characterize small 6 MV photon beams. Output factors, OCR and PDD were measured with shielded and unshielded silicon detectors in a radiation field analyzer system at reference condition. Water equivalent solid phantom were used while irradiating EBT3 films. From multiuser data, diodes underestimated output factor by 3% for collimator fields ≤ 10 mm, while EBT3 underestimated the output factor by 3.9% for 5 mm collimator. 1D Gamma analysis of OCR between diode and film, results in gamma ≤ 1 for all measured points with 1 mm distance to agreement (DTA) and 1% relative dose difference (DD). Dose at surface is overestimated with diodes compared to EBT3. PDD results were within 2% relative dose values between diode and EBT3 except for 5 mm collimator. Except for small collimator fields of up to 10 mm, results of output factor, OCR, PDD of all detectors used in this study exhibited similar results. Relative dose measurements with Gafchromic EBT3 in this work show that EBT3 films can be used effectively as an independent tool to verify commissioning beam data of small fields only after careful verification of methodology for any systematic errors with appropriate readout procedure.

scholarly journals FLUKA Monte Carlo for Basic Dosimetric Studies of Dual Energy Medical Linear Accelerator

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
K. Abdul Haneefa ◽  
T. Siji Cyriac ◽  
M. M. Musthafa ◽  
R. Ganapathi Raman ◽  
V. T. Hridya ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Linear Accelerator ◽  
Dual Energy ◽  
General Purpose ◽  
Experimental Measurements ◽  
Monte Carlo Code ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Medical Linear Accelerator ◽  
Cylindrical Ionization Chamber

General purpose Monte Carlo code for simulation of particle transport is used to study the basic dosimetric parameters like percentage depth dose and dose profiles and compared with the experimental measurements from commercial dual energy medical linear accelerator. Varian Clinac iX medical linear accelerator with dual energy photon beams (6 and 15 MV) is simulated using FLUKA. FLAIR is used to visualize and edit the geometry. Experimental measurements are taken for 100 cm source-to-surface (SSD) in 50 × 50 × 50 cm3 PTW water phantom using 0.12 cc cylindrical ionization chamber. Percentage depth dose for standard square field sizes and dose profiles for various depths are studied in detail. The analysis was carried out using ROOT (a DATA analysis frame work developed at CERN) system. Simulation result shows good agreement in percentage depth dose and beam profiles with the experimental measurements for Varian Clinac iX dual energy medical linear accelerator.

Photon and photon–neutron experimental dosimetry in Grid therapy with 18 MV photon beams

2020 ◽  
pp. 1-7
Author(s):  
Sareh Tajiki ◽  
Somayeh Gholami ◽  
Mahbod Esfahani ◽  
Ali Rastjoo ◽  
Amir Hakimi ◽  
...  
Keyword(s):  
High Energy ◽  
Photon Beam ◽  
Photon Beams ◽  
Effective Technique ◽  
Conventional Radiotherapy ◽  
Output Factor ◽  
Depth Dose ◽  
Thermoluminescence Dosimetry ◽  
Photon Dosimetry ◽  
Grid Block

Abstract Propose: Spatially fractionated Grid radiation therapy (SFGRT) in an effective technique for bulky and radio-sensitive tumours. SFGRT using a constructed block has been used to evaluate the photon and photo-neutron (PN) dose measurement in 18-MV photon beam energy. Methods and materials: A mounted Grid block on to a Varian Clinac 2100c linear accelerator was used to perform photon dosimetry. The percentage depth dose, in-plane and cross-plane beam profile and output factor was measured by ionization chamber in water. The PN contamination was measured after photon dosimetry using the combination of thermoluminescence dosimetry types 600 and 700, and Polycarbonate Film dosimeters on the surface and in the maximum depth dose (dmax) of solid water™ slabs. Results: The valley-to-peak ration for 6 and 18 MV photon beams obtained from the beam profiles was ~35 and 72%, respectively. Fast and thermal PN equivalent dose decreased in the Grid field compared to an open field (without Grid). Conclusion: The Grid therapy dosimetry compared to the conventional radiotherapy (without the grid) the production of fast and thermal neutrons were reduced. Using of a Grid block in high-energy photon beams for a long period of the treatment continuously might be a new source of contamination due to the interaction of photon beam resulting the activation of the Grid block

Computational Modeling and Simulation of Linear Accelerator Performance for General Radiotherapy

2019 ◽  
Vol 23 (2) ◽  
Author(s):  
Andelson Berondo ◽  
◽  
Lilian Rodriguez ◽  
Alwielland Bello ◽  
◽  
...  
Keyword(s):  
Monte Carlo ◽  
Computational Modeling ◽  
Modeling And Simulation ◽  
Linear Accelerator ◽  
Depth Dose ◽  
Computational Modeling And Simulation

linear accelerator, depth-dose, Geant4, Monte Carlo

Percentage depth dose fragmentation for investigating and assessing the photon beam dosimetry quality

2018 ◽  
Vol 18 (03) ◽  
pp. 280-284 ◽  
Author(s):  
Mohamed Bencheikh ◽  
Abdelmajid Maghnouj ◽  
Jaouad Tajmouati
Keyword(s):  
Exponential Decay ◽  
Target Volume ◽  
Photon Beam ◽  
Field Size ◽  
Photon Beams ◽  
Energy Agency ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Beam Dosimetry

AbstractAimThe purpose of this study is to introduce a new approach to assess the dosimetry quality of photon beam with energy and irradiation field size. This approach is based on percentage depth dose (PDD) fragmentation for investigating the dosimetry quality.Materials and methodsFor the investigation of the dosimetry quality of 6 and 18 MV photon beams, we have proceeded to fragment the PDD at different field sizes. This approach checks the overall PDD and is not restricted to the exponential decay regions, as per the International Atomic Energy Agency Technical Reports Series No 398 and the American Association of Physicist in Medicine Task Group 51 recommendations.Results and discussionThe 6 MV photon beam deposited more energy in the target volume than the 18 MV photon beam. The dose delivered by the 6 MV beam is greater by a factor of 1·5 than that delivered by the 18 MV beam in the build-up region and the dose delivered by the 6 MV beam is greater by a factor of 2·6 than that delivered by the 18 MV beam in the electronic equilibrium and the exponential decay regions.ConclusionThe dose measured at different points of the beam is higher for 6 MV than for 18 MV photon beam. Therefore, the 6 MV beam is more dosimetrically efficient than the 18 MV beam. Using the proposed approach, we can assess the dosimetry quality by taking into account overall PDD not only in the exponential decay region but also in the field.

scholarly journals The effects of cutouts on output, mean energy and percentage depth dose of 12 and 14 MeV electrons

2011 ◽  
Vol 36 (4) ◽  
pp. 213 ◽  
Author(s):  
Navid Khaledy ◽  
Dariush Sardari ◽  
Azim Arbabi
Keyword(s):  
Percentage Depth Dose ◽  
Depth Dose

scholarly journals Applications and benefits of using gradient percentage depth dose instead of percentage depth dose for electron and photon beams in radiotherapy

2021 ◽  
Vol 27 (1) ◽  
pp. 25-29
Author(s):  
Labinot Kastrati ◽  
Gezim Hodolli ◽  
Sehad Kadiri ◽  
Elvin Demirel ◽  
Lutfi Istrefi ◽  
...  
Keyword(s):  
Electron Beams ◽  
Published Data ◽  
Photon Beams ◽  
Data Set ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Electron And Photon

Abstract Introduction: The aim of this study is to analyze the gradient of percentage depth dose for photon and electron beams of LINACs and to simplify the data set. Materials and Methods: Dosimetry measurements were performed in accordance with Technical Reports Series No. 398 IAEA. Results and discussion: The gradient of percentage depth dose was calculated and compared with the available published data. Conclusion: Instead of percentage depth dose for increasing and decreasing parts, the findings suggest using only two numbers for specific gradient of dose, separately. In this way, they can replace the whole set of the percentage depth dose (PDD).

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