Experimental measurements and Monte Carlo modelling of the XSTRAHL 150 superficial X-ray therapy unit

2014 ◽  
Vol 14 (1) ◽  
pp. 43-55
Author(s):  
Fayez H. H. Al-Ghorabie
Keyword(s):  
Monte Carlo ◽  
Theoretical Calculations ◽  
Beam Quality ◽  
Patient Treatment ◽  
Experimental Measurements ◽  
Monte Carlo Code ◽  
X Ray ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Good Agreement

AbstractBackgroundSuperficial X-ray therapy units are used for the treatment of certain types of skin cancer and some severe dermatological conditions. The performance assessment and beam characteristics of the superficial unit are very important to ensure accurate dose delivery during patient treatment. Both experimental measurements and Monte Carlo calculations can be used for this purpose.PurposeThis study aims to investigate whether it is possible to reproduce experimentally measured data for the XSTRAHL 150 superficial X-ray unit with simulations using the BEAMnrc Monte Carlo code.Materials and MethodsThe experimental procedure applied in this study included the following: experimental measurements of different X-ray spectra, half-value layers, percentage depth dose and beam profiles. Monte Carlo modelling of the XSTRAHL 150 unit was performed with the BEAMnrc code. The validity of the model was checked by comparing the theoretical calculations with experimental measurements.ResultsThere was good agreement (∼1%) between experimentally measured and simulated X-ray spectra. Results of half-value layers obtained from simulated and measured spectra showed that there was a maximum of 3·6% difference between BEAMnrc and measurements and a minimum of 2·3%. In addition, simulated percentage depth dose and profile curves have been compared against experimental measurements and show good agreement (within 2% for the depth dose curves and 3–5% for beam profile curves, depending on the applicator size).ConclusionThe results of this study provide information about particles’ interaction in different kilovoltage and filter combinations. This information is useful for X-ray tube design and development of new target/filter combinations to improve beam quality in superficial X-ray radiotherapy. The data presented here may provide a base for comparison and a reference for other or potential new users of the XSTRAHL 150 X-ray unit.

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.

MONTE CARLO CODE FOR STUDY OF THE RESPONSE FUNCTION OF Si(Li) DETECTORS FOR X-RAYS

1999 ◽  
Vol 09 (03n04) ◽  
pp. 135-141
Author(s):  
KÁROLY TŐKÉSI ◽  
TAKESHI MUKOYAMA
Keyword(s):  
Monte Carlo ◽  
Present Model ◽  
Monte Carlo Code ◽  
X Rays ◽  
Model Calculations ◽  
X Ray ◽  
Line Shapes ◽  
Calculated Line ◽  
The Individual ◽  
Good Agreement

For more detailed understanding of the line shape of X-ray peaks observed with Si ( Li ) detectors, a new Monte Carlo code was developed and tested in the range of incident X-ray energy less than 5 keV. In our simulation the individual elastic and inelastic processes in the solid and the charge collection probabilities in the different region of detectors are taken into account. The results of our model calculations are compared with experimental data. In general, good agreement is found between the experimental and calculated line shapes. This fact demonstrates the validity of the present model.

scholarly journals MoCA: A Monte Carlo code for Comptonisation in Astrophysics

2018 ◽  
Vol 619 ◽  
pp. A105 ◽  
Author(s):  
Francesco Tamborra ◽  
Giorgio Matt ◽  
Stefano Bianchi ◽  
Michal Dovčiak
Keyword(s):  
Monte Carlo ◽  
Optical Thickness ◽  
Thermal Emission ◽  
Single Photon ◽  
Spherical Geometry ◽  
Accretion Disc ◽  
Monte Carlo Code ◽  
X Ray ◽  
First Results ◽  
Good Agreement

We present a new Monte Carlo code for Comptonisation in Astrophysics (MoCA). To our knowledge MoCA is the first code that uses a single photon approach in a full special relativity scenario, and including also Klein–Nishina effects as well as polarisation. In this paper we describe in detail how the code works, and show first results from the case of extended coronae in accreting sources Comptonising the accretion disc thermal emission. We explored both a slab and a spherical geometry, to make comparison with public analytical codes more easy. Our spectra are in good agreement with those from analytical codes for low/moderate optical depths, but differ significantly, as expected, for optical depths larger than a few. Klein–Nishina effects become relevant above 100 keV depending on the optical thickness and thermal energy of the corona. We also calculated the polarisation properties for the two geometries, which show that X-ray polarimetry is a very useful tool to discriminate between them.

scholarly journals Monte Carlo derivation of filtered tungsten anode X-ray spectra for dose computation in digital mammography

2015 ◽  
Vol 48 (6) ◽  
pp. 363-367 ◽  
Author(s):  
Lucas Paixão ◽  
Bruno Beraldo Oliveira ◽  
Carolina Viloria ◽  
Marcio Alves de Oliveira ◽  
Maria Helena Araújo Teixeira ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Digital Mammography ◽  
Relative Difference ◽  
Monte Carlo Code ◽  
Solid State Detector ◽  
X Ray ◽  
Direct Radiography ◽  
State Detector ◽  
Tungsten Anode ◽  
Good Agreement

Abstract Objective: Derive filtered tungsten X-ray spectra used in digital mammography systems by means of Monte Carlo simulations. Materials and Methods: Filtered spectra for rhodium filter were obtained for tube potentials between 26 and 32 kV. The half-value layer (HVL) of simulated filtered spectra were compared with those obtained experimentally with a solid state detector Unfors model 8202031-H Xi R/F & MAM Detector Platinum and 8201023-C Xi Base unit Platinum Plus w mAs in a Hologic Selenia Dimensions system using a direct radiography mode. Results: Calculated HVL values showed good agreement as compared with those obtained experimentally. The greatest relative difference between the Monte Carlo calculated HVL values and experimental HVL values was 4%. Conclusion: The results show that the filtered tungsten anode X-ray spectra and the EGSnrc Monte Carlo code can be used for mean glandular dose determination in mammography.

scholarly journals Monitoring beam-quality constancy considering uncertainties associated with ionization chambers in Daily QA3 device

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246845
Author(s):  
Su Chul Han ◽  
Jihun Kim ◽  
Min Cheol Han ◽  
Kyung Hwan Chang ◽  
Kwangwoo Park ◽  
...  
Keyword(s):  
Beam Quality ◽  
Energy Levels ◽  
Repeated Measurements ◽  
Secondary System ◽  
Ionization Chambers ◽  
X Ray ◽  
Water Phantom ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Daily Energy

This study evaluates the changes occurring in the X-ray energy of a linear accelerator (LINAC) using a Daily QA3 detector system. This is accomplished by comparing the Daily QA3 results against those obtained using a water phantom. The X-energy levels of a LINAC were monitored over a duration of 1 month using the Daily QA3 system. Moreover, to account for the uncertainty, the reproducibility of the Daily QA3 ionization-chamber results was assessed by performing repeated measurements (12 per day). Subsequently, the energy-monitoring results were compared with the energy-change results calculated using the water-phantom percentage depth dose (PDD) ratio. As observed, the 6- and 10-MV beams experienced average daily energy-level changes of (-0.30 ± 0.32)% and (0.05 ± 0.38)%, respectively, during repeated measurements. The corresponding energy changes equaled (-0.30 ± 0.55)% and (-0.05 ± 0.48)%, respectively, when considering the measurement uncertainty. The Daily QA3 measurements performed at 6 MV demonstrated a variation of (2.15 ± 0.81)% (i.e., up to 3%). Meanwhile, the corresponding measurements performed using a water phantom demonstrated an increase in the PDD ratio from 0.577 to 0.580 (i.e., approximately 0.5%). At 10 MV, the energy variation in the Daily QA3 measurements equaled (-0.41 ± 0.82)% (i.e., within 1.5%), whereas the corresponding water phantom PDD ratio remained constant at 0.626. These results reveal that the Daily QA3 system can be used to monitor small energy changes occurring within radiotherapy machines. This demonstrates its potential for use as a secondary system for monitoring energy changes as part of the daily quality-assurance workflow.

scholarly journals Benchmarking of Siemens Linac in Electron Modes: 8-14 MeV Electron Beams

2018 ◽  
Vol 8 (2) ◽  
Author(s):  
H Dowlatabadi ◽  
A A Mowlavi ◽  
M Ghorbani ◽  
S Mohammadi ◽  
F Akbari
Keyword(s):  
Monte Carlo ◽  
Radiation Treatment ◽  
Electron Beams ◽  
Dose Profile ◽  
Depth Dose ◽  
Mcnpx Code ◽  
Gamma Index ◽  
Simulation Results ◽  
Mc Simulation ◽  
Good Agreement

Introduction: Radiation therapy using electron beams is a promising method due to its physical dose distribution. Monte Carlo (MC) code is the best and most accurate technique for forespeaking the distribution of dose in radiation treatment of patients.Materials and Methods: We report an MC simulation of a linac head and depth dose on central axis, along with profile calculations. The purpose of the present research is to carefully analyze the application of MC methods for the calculation of dosimetric parameters for electron beams with energies of 8–14 MeV at a Siemens Primus linac. The principal components of the linac head were simulated using MCNPX code for different applicators. Results: The consequences of measurements and simulations revealed a good agreement. Gamma index values were below 1 for most points, for all energy values and all applicators in percent depth dose and dose profile computations. A number of states exhibited rather large gamma indices; these points were located at the tail of the percent depth dose graph; these points were less used in in radiotherapy. In the dose profile graph, gamma indices of most parts were below 1. The discrepancies between the simulation results and measurements in terms of Zmax, R90, R80 and R50 were insignificant. The results of Monte Carlo simulations showed a good agreement with the measurements. Conclusion: The software can be used for simulating electron modes of a Siemens Primus linac when direct experimental measurements are not feasible.

Secondary Fluorescence of 3D Heterogeneous Materials Using a Hybrid Model

2020 ◽  
Vol 26 (3) ◽  
pp. 484-496
Author(s):  
Yu Yuan ◽  
Hendrix Demers ◽  
Xianglong Wang ◽  
Raynald Gauvin
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Analytical Model ◽  
Hybrid Model ◽  
Three Dimensional ◽  
Heterogeneous Materials ◽  
X Ray ◽  
The Monte Carlo Method ◽  
Secondary Fluorescence ◽  
Good Agreement

AbstractIn electron probe microanalysis or scanning electron microscopy, the Monte Carlo method is widely used for modeling electron transport within specimens and calculating X-ray spectra. For an accurate simulation, the calculation of secondary fluorescence (SF) is necessary, especially for samples with complex geometries. In this study, we developed a program, using a hybrid model that combines the Monte Carlo simulation with an analytical model, to perform SF correction for three-dimensional (3D) heterogeneous materials. The Monte Carlo simulation is performed using MC X-ray, a Monte Carlo program, to obtain the 3D primary X-ray distribution, which becomes the input of the analytical model. The voxel-based calculation of MC X-ray enables the model to be applicable to arbitrary samples. We demonstrate the derivation of the analytical model in detail and present the 3D X-ray distributions for both primary and secondary fluorescence to illustrate the capability of our program. Examples for non-diffusion couples and spherical inclusions inside matrices are shown. The results of our program are compared with experimental data from references and with results from other Monte Carlo codes. They are found to be in good agreement.

Sign in / Sign up

Export Citation Format

Share Document