SU-E-T-145: Scanned Percent Depth Dose Curve Discrepancy for Varian TrueBeam Flattening-Filter-Free Photon Beams Using Very Small Sensitive Volume Ion Chamber

2013 ◽  
Vol 40 (6Part12) ◽  
pp. 237-237
Author(s):  
H Zhao ◽  
B Wang ◽  
P Rassiah-Szegedi ◽  
Y Huang ◽  
V Sarkar ◽  
...  
Keyword(s):  
Sensitive Volume ◽  
Photon Beams ◽  
Ion Chamber ◽  
Depth Dose ◽  
Flattening Filter Free ◽  
Dose Curve ◽  
Depth Dose Curve ◽  
Flattening Filter

SU-E-T-562: Scanned Percent Depth Dose Curve Discrepancy for Photon Beams with Physical Wedge in Place (Varian IX) Using Different Sensitive Volume Ion Chambers

2014 ◽  
Vol 41 (6Part20) ◽  
pp. 357-357
Author(s):  
H Zhao ◽  
V Sarkar ◽  
P Rassiah-Szegedi ◽  
Y Huang ◽  
M Szegedi ◽  
...  
Keyword(s):  
Sensitive Volume ◽  
Photon Beams ◽  
Depth Dose ◽  
Dose Curve ◽  
Depth Dose Curve ◽  
Ion Chambers

Study of unflattened photon beams shaped by multileaf collimator using BEAMnrc code

2016 ◽  
Vol 15 (4) ◽  
pp. 392-401
Author(s):  
Ankit kajaria ◽  
Neeraj Sharma ◽  
Shiru Sharma ◽  
Satyajit Pradhan ◽  
Abhijit Mandal ◽  
...  
Keyword(s):  
Beam Line ◽  
Photon Beam ◽  
Field Size ◽  
Photon Beams ◽  
Multileaf Collimators ◽  
Depth Dose ◽  
Beamnrc Code ◽  
Flattening Filter Free ◽  
Flattening Filter ◽  
Beam Delivery

AbstractPurposeIn our study basic dosimetric properties of a flattening filter free 6 MV photon beam shaped by multileaf collimators (MLC) is examined using the Monte Carlo (MC) method.Methods and MaterialsBEAMnrc code was used to make a MC simulation model for 6 MV photon beam based on Varian Clinic 600 unique performance linac, operated with and without a flattening filter in beam line. Dosimetric features including central axis depth dose, beam profiles, photon and electron spectra were calculated and compared for flattened and unflattened cases.ResultsDosimetric field size and penumbra were found to be smaller for unflattened beam, and the decrease in field size was less for MLC shaped in comparison with jaw-shaped unflattened beam. Increase in dose rate of >2·4 times was observed for unflattened beam indicating a shorter beam delivery time for treatment. MLC leakage was found to decrease significantly when the flattening filter was removed from the beam line. The total scatter factor showed slower deviation with field sizes for unflattened beam indicating a reduced head scatter.ConclusionsOur study demonstrated that improved accelerator characteristics can be achieved by removing flattening filter from beam line.

scholarly journals Depth Dose Enhancement on Flattening-Filter-Free Photon Beam: A Monte Carlo Study in Nanoparticle-Enhanced Radiotherapy

2020 ◽  
Vol 10 (20) ◽  
pp. 7052
Author(s):  
James C. L. Chow
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Study ◽  
Photon Beam ◽  
Depth Range ◽  
Photon Beams ◽  
Dose Enhancement ◽  
Au Nps ◽  
Depth Dose ◽  
Flattening Filter Free ◽  
Flattening Filter

The aim of this study is to investigate the variations of depth dose enhancement (DDE) on different nanoparticle (NP) variables, when using the flattening-filter-free (FFF) photon beam in nanoparticle-enhanced radiotherapy. Monte Carlo simulation under a macroscopic approach was used to determine the DDE ratio (DDER) with variables of NP material (gold (Au) and iron (III) oxide (Fe2O3)), NP concentration (3–40 mg/mL) and photon beam (10 MV flattening-filter (FF) and 10 MV FFF). It is found that Au NPs had a higher DDER than Fe2O3 NPs, when the depths were shallower than 6 and 8 cm for the 10 MV FF and 10 MV FFF photon beams, respectively. However, in a deeper depth range of 10–20 cm, DDER for the Au NPs was lower than Fe2O3 NPs mainly due to the beam attenuation and photon energy distribution. It is concluded that DDER for the Au NPs and Fe2O3 NPs decreased with an increase of depth in the range of 10–20 cm, with rate of decrease depending on the NP material, NP concentration and the use of FF in the photon beam.

Calypso’s array attenuation

2015 ◽  
Vol 14 (2) ◽  
pp. 202-207
Author(s):  
Célia Silva ◽  
Dalila Mateus ◽  
Sandra Vieira ◽  
Milton Rodrigues ◽  
Margarida Eiras ◽  
...  
Keyword(s):  
Treatment Plan ◽  
Field Size ◽  
Beam Angle ◽  
Photon Beams ◽  
Beam Path ◽  
Attenuation Effect ◽  
Ion Chamber ◽  
Flattening Filter Free ◽  
Flattening Filter ◽  
Attenuation Values

AbstractIntroductionThe Calypso 4D Localization System gives the possibility to track the tumour during treatment, with no additional ionising radiation delivered. To monitor the patient continuously an array is positioned above the patient during the treatment. We intend to study, for various gantry angles, the attenuation effect of the array for 6- and 10 MV and flattening filter free (FFF) 6- and FFF 10 MV photon beams.Materials and methodsMeasurements were performed using an ion chamber placed in a slab phantom positioned at the linac isocenter for 6 MV, 10 MV, FFF 6 MV and FFF 10 MV photon beams. Measurements were performed with and without array above the phantom for 0°, 10°, 20°, 40° and 50° beam angle for a True Beam STx linac, for 5×5 and 10×10 and 15×15 cm2 field size beams to evaluate the attenuation of the array. A VMAT treatment plan was measured using an ArcCheck with and without the array in the beam path.Results and discussionAttenuation measured values were up to 3%. Attenuation values were between 1 and 2% with the exception of the 30°–50° gantry angles which were up to 3.3%. The ratio values calculated in the ArcCheck for relative dose and absolute dose 10 were both 1·00.ConclusionAttenuation of the treatment beam by the Calypso array is within acceptable limits.

scholarly journals Clinical advantages of using unflattened 6-MV and 10-MV photon beams generated by the medical accelerator Elekta Versa HD based on their dosimetric parameters in comparison to conventional beams

Nukleonika ◽  
2019 ◽  
Vol 64 (3) ◽  
pp. 77-86
Author(s):  
Błażej Baic ◽  
Beata Kozłowska ◽  
Robert Kwiatkowski ◽  
Marcin Dybek
Keyword(s):  
Correction Factor ◽  
Scatter Correction ◽  
Beam Profile ◽  
Technical Solution ◽  
Photon Beams ◽  
Depth Dose ◽  
Flattening Filter Free ◽  
Wide Energy ◽  
Flattening Filter ◽  
Oncology Center

Abstract Photon beams with wide energy ranges from 4 MV to 25 MV are commonly used in radiotherapy nowadays. In recent years, there has been a strong interest in a certain modification of a radiotherapeutic apparatus by the application of the so-called flattening filter-free (FFF) beam. Several advantages of FFF beams over standard flattening filter (FF) beams are noticed, and this technical solution has aroused great interest among radiotherapeutic facilities. The goal of the present study is to investigate the differences between the conventional FF and unflattened FFF 6-MV and 10-MV photon beams in some basic dosimetric parameters and their influence on the whole radiotherapeutic treatment. The data provided here include the detailed characteristics as follows: percent depth dose (PDD), beam profile, edge of a half-profile, total scatter correction factor (TSCF) and head scatter correction factor (HSCF) for FF and FFF 6-MV and 10-MV photon beams from the Elekta Versa HD accelerator in the Katowice Oncology Center in Poland.

scholarly journals Comparative investigation of beam quality index Q on flattening filter and flattening filter free 6 and 15 MV photon beams of an medical linear accelerator

2017 ◽  
Vol 3 (2) ◽  
pp. 287-290
Author(s):  
Michael Schaks ◽  
Johannes Zähle ◽  
Martin Janich ◽  
Patrick Hübsch ◽  
Nico Homonnay ◽  
...  
Keyword(s):  
Linear Accelerator ◽  
Quality Index ◽  
Beam Quality ◽  
Comparative Investigation ◽  
Central Axis ◽  
Photon Beams ◽  
Medical Linear Accelerator ◽  
Flattening Filter Free ◽  
Flattening Filter ◽  
Beam Quality Correction Factor

AbstractAn Elekta Synergy LINAC was used to investigate the beam quality index Q and the beam quality correction factor kQ, which is used for absolute dosimetry, in off-axis photon fields. It was found that the beam quality index Q of the photon energies with flattening filter decreases with increasing distance to the central axis, at 6 MV by 4.27% and at 15 MV by 3.98% inside a range of 15 cm off-axis. The beam quality index for flattening filter free photon fields also decreases with increasing distance to the central axis. In this case Q changed only by 1.01% inside the above range.

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