scholarly journals Use of Flattening Filter-Free Photon Beams in Treating Medulloblastoma: A Dosimetric Evaluation

ISRN Oncology ◽  
2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Pichandi Anchineyan ◽  
Ganesh K. Mani ◽  
Jerrin Amalraj ◽  
Balaji Karthik ◽  
Surega Anbumani
Keyword(s):  
Intensity Modulated Radiation Therapy ◽  
Data Sets ◽  
Photon Beams ◽  
Treatment Efficiency ◽  
Multileaf Collimators ◽  
Conformal Therapy ◽  
Flattening Filter Free ◽  
Flattening Filter ◽  
Ct Data ◽  
Craniospinal Axis

Aim. To evaluate the dosimetric benefits of flattening filter-free (FFF) photon beams in intensity modulated radiation therapy (IMRT) and Rapid Arc (RA) over conventional CSI methods. Methods and Materials. Five patients treated with IMRT using static multileaf collimators (MLC) were randomly selected for this retrospective study. Dynamic MLC IMRT, RA, and conformal therapy (3DCRT) were iterated with the same CT data sets with and without flattening filter photons. Total dose prescribed was 28.80 Gy in 16 fractions. Dosimetric parameters such as Dmax⁡, Dmin⁡, Dmean, V95%, V107%, DHI, and CI for PTV and Dmax⁡, Dmean, V80%, V50%, V30%, and V10% for OARs were extracted from DVHs. Beam on time (BOT) for various plans was also compared. Results. FFF RA therapy (6F_RA) resulted in highly homogeneous and conformal doses throughout the craniospinal axis. 3DCRT resulted in the highest V107% (SD) 46.97±28.6, whereas flattening filter (FF) and FFF dynamic IMRT had a minimum V107%. 6F_RA and 6F_DMLC resulted in lesser doses to thyroid, eyes, esophagus, liver, lungs, and kidneys. Conclusion. FFF IMRT and FFF RA for CSI have definite dosimetric advantages over 3DCRT technique in terms of target coverage and OAR sparing. Use of FFF in IMRT resulted in 50% reduction in BOT, thereby increasing the treatment efficiency.

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 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.

SU-DD-A1-03: Dosimetric Properties of Photon Beams From a Flattening Filter Free Clinical Accelerator

2005 ◽  
Vol 32 (6Part2) ◽  
pp. 1896-1896 ◽  
Author(s):  
O Vassiliev ◽  
U Titt ◽  
S Kry ◽  
F Poenisch ◽  
M Gillin ◽  
...  
Keyword(s):  
Photon Beams ◽  
Flattening Filter Free ◽  
Flattening Filter

TH-E-224A-06: Dosimetric Properties of 8 and 10 MV Photon Beams From a Flattening Filter Free Clinical Accelerator

2006 ◽  
Vol 33 (6Part23) ◽  
pp. 2292-2292 ◽  
Author(s):  
O Vassiliev ◽  
U Titt ◽  
M Gillin ◽  
R Mohan
Keyword(s):  
Photon Beams ◽  
Flattening Filter Free ◽  
Flattening Filter

SU-E-T-719: Surface Dose Evaluation of the Equivalent Quality Flattening Filter-Free Photon Beams

2015 ◽  
Vol 42 (6Part23) ◽  
pp. 3502-3502
Author(s):  
M Meshram ◽  
S Pramanik ◽  
C P Ranjith ◽  
M Meshram
Keyword(s):  
Surface Dose ◽  
Photon Beams ◽  
Dose Evaluation ◽  
Flattening Filter Free ◽  
Flattening Filter

SU-F-T-511: Feasibility Study of Using Flattening-Filter-Free Photon Beams to Deliver Conventional Flat Beam

2016 ◽  
Vol 43 (6Part21) ◽  
pp. 3580-3581
Author(s):  
N Potter ◽  
S Lebron ◽  
G Yan ◽  
J Li ◽  
C Liu ◽  
...  
Keyword(s):  
Feasibility Study ◽  
Photon Beams ◽  
Flattening Filter Free ◽  
Flattening Filter ◽  
Flat Beam
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