SU-E-T-113: Volume Effect Correction Factor KV for Small-Field Photon Dosimetry with Ionization Chambers

2012 ◽  
Vol 39 (6Part11) ◽  
pp. 3729-3729
Author(s):  
HK Looe ◽  
TS Stelljes ◽  
D Harder ◽  
B Poppe
Keyword(s):  
Correction Factor ◽  
Volume Effect ◽  
Small Field ◽  
Ionization Chambers ◽  
Photon Dosimetry

The ‘cutting away’ of potential secondary electron tracks explains the effects of beam size and detector wall density in small-field photon dosimetry

2017 ◽  
Vol 63 (1) ◽  
pp. 015001 ◽  
Author(s):  
Hui Khee Looe ◽  
Björn Delfs ◽  
Daniela Poppinga ◽  
Ping Jiang ◽  
Dietrich Harder ◽  
...  
Keyword(s):  
Secondary Electron ◽  
Small Field ◽  
Beam Size ◽  
Photon Dosimetry

On the Monte Carlo simulation of small-field micro-diamond detectors for megavoltage photon dosimetry

2015 ◽  
Vol 61 (1) ◽  
pp. L1-L10 ◽  
Author(s):  
Pedro Andreo ◽  
Hugo Palmans ◽  
Maria Marteinsdóttir ◽  
Hamza Benmakhlouf ◽  
Åsa Carlsson-Tedgren
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Small Field ◽  
Photon Dosimetry

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 Commissioning of a PTW 34070 large-area plane-parallel ionization chamber for small field megavoltage photon dosimetry

2017 ◽  
Vol 18 (6) ◽  
pp. 206-217 ◽  
Author(s):  
Tom Kupfer ◽  
Joerg Lehmann ◽  
Duncan J. Butler ◽  
Ganesan Ramanathan ◽  
Tracy E. Bailey ◽  
...  
Keyword(s):  
Ionization Chamber ◽  
Small Field ◽  
Large Area ◽  
Plane Parallel ◽  
Photon Dosimetry
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