SU-E-T-469: A Practical Approach for the Determination of Small Field Output Factors Using Published Monte Carlo Derived Correction Factors

2014 ◽  
Vol 41 (6Part18) ◽  
pp. 334-334
Author(s):  
E Calderon ◽  
D Siergiej
Keyword(s):  
Monte Carlo ◽  
Practical Approach ◽  
Small Field ◽  
Correction Factors ◽  
Output Factors

OC-0194 Monte Carlo determination of magnetic field correction factors kB,Q for dosimetry in 1.5T MR-Linacs

2021 ◽  
Vol 161 ◽  
pp. S123-S124
Author(s):  
V. Margaroni ◽  
E.P. Pappas ◽  
A. Episkopakis ◽  
P. Karaiskos
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Correction Factors

Investigation of field output factors using IAEA-AAPM TRS-483 code of practice recommendations and Monte Carlo simulation for 6 MV photon beams

2021 ◽  
pp. 1-6
Author(s):  
Sumalee Yabsantia ◽  
Sivalee Suriyapee ◽  
Nakorn Phaisangittisakul ◽  
Sornjarod Oonsiri ◽  
Taweap Sanghangthum ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Field Method ◽  
Correction Factors ◽  
Photon Beams ◽  
Small Field Dosimetry ◽  
Code Of Practice ◽  
Edge Detectors ◽  
Output Factors ◽  
Measured Field ◽  
Mc Simulation

Abstract Introduction: This study aims to experimentally determine field output factors using the methodologies suggested by the IAEA-AAPM TRS-483 for small field dosimetry and compare with the calculation from Monte Carlo (MC) simulation. Methods: The IBA-CC01, Sun Nuclear EDGE and IBA-SFD detectors were employed to determine the uncorrected and the corrected field output factors for 6 MV photon beams. Measurements were performed at 100 cm source to axis distance, 10 cm depth in water, and the field sizes ranged from 1 × 1 to 10 × 10 cm2. The use of field output correction factors proposed by the TRS-483 was utilised to determine field output factors. The measured field output factors were compared to that calculated using the egs_chamber user code. Results: The decrease in the percentage standard deviation of the measured three detectors was observed after applying the field output correction factors. Measured field output factors using CC01 and EDGE detectors agreed with MC values within 3% for field sizes down to 1 × 1 cm2, except the SFD detector. Conclusions: The corrected field output factors agree with the calculation from MC, except the SFD detector. CC01 and EDGE are suitable for determining field output factors, while the SFD may need more implementation of the intermediate field method.

scholarly journals Estimation of Dosimetric Parameters based on KNR and KNCSF Correction Factors for Small Field Radiation Therapy at 6 and 18 MV Linac Energies using Monte Carlo Simulation Methods

2019 ◽  
Vol 9 (1Feb) ◽  
Author(s):  
S A Rahimi ◽  
B Hashemi ◽  
S R Mahdavi
Keyword(s):  
Monte Carlo ◽  
Correction Factor ◽  
Reference Conditions ◽  
Field Size ◽  
Monte Carlo Code ◽  
Small Field ◽  
Correction Factors ◽  
Photon Beams ◽  
Small Field Dosimetry ◽  
Circular Field

Background: Estimating dosimetric parameters for small fields under non-reference conditions leads to significant errors if done based on conventional protocols used for large fields in reference conditions. Hence, further correction factors have been introduced to take into account the influence of spectral quality changes when various detectors are used in non-reference conditions at different depths and field sizes.Objective: Determining correction factors (KNR and KNCSF) recommended recently for small field dosimetry formalism by American Association of Physicists in Medicine (AAPM) for different detectors at 6 and 18 MV photon beams.Methods: EGSnrc Monte Carlo code was used to calculate the doses measured with different detectors located in a slab phantom and the recommended KNR and KNCSF correction factors for various circular small field sizes ranging from 5-30 mm diameters. KNR and KNCSF correction factors were determined for different active detectors (a pinpoint chamber, EDP-20 and EDP-10 diodes) in a homogeneous phantom irradiated to 6 and 18 MV photon beams of a Varian linac (2100C/D).Results: KNR correction factor estimated for the highest small circular field size of 30 mm diameter for the pinpoint chamber, EDP-20 and EDP-10 diodes were 0.993, 1.020 and 1.054; and 0.992, 1.054 and 1.005 for the 6 and 18 MV beams, respectively. The KNCSF correction factor estimated for the lowest circular field size of 5 mm for the pinpoint chamber, EDP-20 and EDP-10 diodes were 0.994, 1.023, and 1.040; and 1.000, 1.014, and 1.022 for the 6 and 18 MV photon beams, respectively.Conclusion: Comparing the results obtained for the detectors used in this study reveals that the unshielded diodes (EDP-20 and EDP-10) can confidently be recommended for small field dosimetry as their correction factors (KNR and KNCSF) was close to 1.0 for all small field sizes investigated and are mainly independent from the electron beam spot size.

scholarly journals Determination of true coincidence correction factors using Monte-Carlo simulation techniques

2014 ◽  
Vol 29 (suppl.) ◽  
pp. 8-13 ◽  
Author(s):  
Dionysios Chionis ◽  
Marilia Savva ◽  
Konstantinos Karfopoulos ◽  
Marios Anagnostakis
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Full Energy Peak ◽  
Correction Factors ◽  
Main Program ◽  
True Coincidence ◽  
Full Energy ◽  
Simulation Techniques ◽  
Energy Peak

Aim of this work is the numerical calculation of the true coincidence correction factors by means of Monte-Carlo simulation techniques. For this purpose, the Monte Carlo computer code PENELOPE was used and the main program PENMAIN was properly modified in order to include the effect of the true coincidence phenomenon. The modified main program that takes into consideration the true coincidence phenomenon was used for the full energy peak efficiency determination of an XtRa Ge detector with relative efficiency 104% and the results obtained for the 1173 keV and 1332 keV photons of 60Co were found consistent with respective experimental ones. The true coincidence correction factors were calculated as the ratio of the full energy peak efficiencies was determined from the original main program PENMAIN and the modified main program PENMAIN. The developed technique was applied for 57Co, 88Y, and 134Cs and for two source-to-detector geometries. The results obtained were compared with true coincidence correction factors calculated from the "TrueCoinc" program and the relative bias was found to be less than 2%, 4%, and 8% for 57Co, 88Y, and 134Cs, respectively.

Sign in / Sign up

Export Citation Format

Share Document