SU-F-J-26: Performance of 2.5MV Portal Imaging in Comparison with KV X-Ray and 6MV and Flattening-Filter-Free 6MV Portal Imaging

2016 ◽  
Vol 43 (6Part9) ◽  
pp. 3411-3411
Author(s):  
J Duan ◽  
Y Yang ◽  
A Faught ◽  
E Subashi ◽  
Q Wu ◽  
...  
Keyword(s):  
Portal Imaging ◽  
X Ray ◽  
Flattening Filter Free ◽  
Flattening Filter

SU-E-T-555: Small Field Dosimetry of the Flattening Filter Free (FFF) X-Ray Photons

2011 ◽  
Vol 38 (6Part19) ◽  
pp. 3617-3617
Author(s):  
Y Wang ◽  
S Easterling ◽  
J Ting
Keyword(s):  
Small Field ◽  
X Ray ◽  
Small Field Dosimetry ◽  
Flattening Filter Free ◽  
Flattening Filter

MO-D-BRB-05: Skin Dose Study of the Flattening Filter Free (FFF) X-Ray Photons

2011 ◽  
Vol 38 (6Part25) ◽  
pp. 3710-3710
Author(s):  
Y Wang ◽  
S Easterling ◽  
J Ting
Keyword(s):  
Skin Dose ◽  
X Ray ◽  
Flattening Filter Free ◽  
Dose Study ◽  
Flattening Filter

scholarly journals Effectiveness of robust optimization in volumetric modulated arc therapy using 6 and 10 MV flattening filter-free beam therapy planning for lung stereotactic body radiation therapy with a breath-hold technique

2020 ◽  
Vol 61 (4) ◽  
pp. 575-585
Author(s):  
Hideharu Miura ◽  
Shuichi Ozawa ◽  
Yoshiko Doi ◽  
Minoru Nakao ◽  
Katsumaro Kubo ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Robust Optimization ◽  
Stereotactic Body Radiation Therapy ◽  
Volumetric Modulated Arc Therapy ◽  
Target Volume ◽  
Breath Holding ◽  
X Ray ◽  
Flattening Filter Free ◽  
Arc Therapy ◽  
Flattening Filter

Abstract We investigated the feasibility of a robust optimization with 6 MV X-ray (6X) and 10 MV X-ray (10X) flattening filter-free (FFF) beams in a volumetric modulated arc therapy (VMAT) plan for lung stereotactic body radiation therapy (SBRT) using a breath-holding technique. Ten lung cancer patients were selected. Four VMAT plans were generated for each patient; namely, an optimized plan based on the planning target volume (PTV) margin and a second plan based on a robust optimization of the internal target volume (ITV) with setup uncertainties, each for the 6X- and 10X-FFF beams. Both optimized plans were normalized by the percentage of the prescription dose covering 95% of the target volume (D95%) to the PTV (1050 cGy × 4 fractions). All optimized plans were evaluated using perturbed doses by specifying user-defined shifted values from the isocentre. The average perturbed D99% doses to the ITV, compared to the nominal plan, decreased by 369.1 (6X-FFF) and 301.0 cGy (10X-FFF) for the PTV-based optimized plan, and 346.0 (6X-FFF) and 271.6 cGy (10X-FFF) for the robust optimized plan, respectively. The standard deviation of the D99% dose to the ITV were 163.6 (6X-FFF) and 158.9 cGy (10X-FFF) for the PTV-based plan, and 138.9 (6X-FFF) and 128.5 cGy (10X-FFF) for the robust optimized plan, respectively. Robust optimized plans with 10X-FFF beams is a feasible method to achieve dose certainty for the ITV for lung SBRT using a breath-holding technique.

scholarly journals Evaluation of Dosimetic Characteristics of Electronic Portal Imaging Device (EPID) for Flattening Filter Free (FFF) Beams

2017 ◽  
Vol 35 (4) ◽  
pp. 361
Author(s):  
Thadpong Chanton ◽  
Sangutid Thongsawad ◽  
Nipon Saiyo ◽  
Nuntawat Udee
Keyword(s):  
Dose Rate ◽  
Field Size ◽  
Electronic Portal Imaging Device ◽  
Monitor Unit ◽  
Good Characteristic ◽  
Imaging Device ◽  
Portal Imaging ◽  
Flattening Filter Free ◽  
Dose Linearity ◽  
Flattening Filter

Objective: To evaluatethe dosimetric characteristics of electronics portal imaging device (EPID) for 6 and 10 megavoltage(MV) of flattening filter-free (FFF) beams.Material and Method: The EPID characteristicsfor FFF beams have been evaluated as follows; saturation with sourcedetector-distance (SDD), saturation with dose rate, dose linearity response with monitor unit (MU), and the scatterd radiation with field size.Results: The saturation of signal was not occurred at 150 cm and 180 cm SDD for 6 and 10 MV of FFF beams, respectively. When the signals were measured with optimal SSD according to vendor suggestion (150 cm and 180 cm), the standard deviation for all dose rate were ±1.35 and ±1.64 CU for 6 and 10 MV of FFF beams,respectively. The dose linearity response showed that EPID has a good linearity response between signals and MU forthe both of 6 and 10 MV of FFF beams. The results of scatterd radiation with field size were found that FFF beams have different respose from flattening filter (FF) beams with the highest differences of 5.50% and 6.78% for 6 and 10 MV of FFF beams, respectively.Conclusion: EPID has a good characteristic for FFF beams, and an extended SSD can be used to reduce the satured signal effects in FFF beams.

scholarly journals Evaluation of a 2D Diode Array Corresponding to Flattening Filter Free X-ray Beams

2018 ◽  
Vol 74 (5) ◽  
pp. 473-479
Author(s):  
Tomoko Kimura ◽  
Jun-ichi Fukunaga ◽  
Taka-aki Hirose ◽  
Ryota Hirayama
Keyword(s):  
Diode Array ◽  
X Ray ◽  
Flattening Filter Free ◽  
Flattening Filter

scholarly journals Dosimetric Characterization of the Dual Layer MLC System for an O-Ring Linear Accelerator

2019 ◽  
Vol 18 ◽  
pp. 153303381988364 ◽  
Author(s):  
Michele M. Kim ◽  
Douglas Bollinger ◽  
Chris Kennedy ◽  
Wei Zou ◽  
Ryan Scheuermann ◽  
...  
Keyword(s):  
Linear Accelerator ◽  
Multileaf Collimator ◽  
Electronic Portal Imaging Device ◽  
Imaging Device ◽  
Portal Imaging ◽  
Electronic Portal Imaging ◽  
Flattening Filter Free ◽  
Flattening Filter ◽  
Dosimetric Leaf Gap

The Halcyon is Varian’s latest linear accelerator that offers a single 6X flattening-filter-free beam with a jawless design that features a new dual layer multileaf collimator system with faster speed and reduced transmission. Dosimetric characteristics of the dual layer multileaf collimator system including transmission, dosimetric leaf gap, and tongue and groove effects were measured. Ionization chambers, diode arrays, and an electronic portal imaging device were used to measure various multileaf collimator characteristics. Transmission through both multileaf collimator banks was found to be 0.008%, while the distal and proximal banks alone had transmission values of 0.4%. The penumbra was slightly sharper for fields using only the distal multileaf collimator bank but found to be largely independent of leaf position with values between 2.7 to 3.0 mm at dmax for the combined multileaf collimator banks. The dosimetric leaf gap was measured for the proximal and distal multileaf collimator banks both individually and together and found to have values of −0.216 mm, −0.225 mm, and 0.964 mm, respectively. Measurements of dosimetric leaf gap at the leaf edge and midline were also performed. Tongue and groove effects were investigated with both the electronic portal imaging device and a 2-dimensional array of diodes.

scholarly journals Contrast Enhancement for Portal Imaging in Nanoparticle-Enhanced Radiotherapy: A Monte Carlo Phantom Evaluation Using Flattening-Filter-Free Photon Beams

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 920 ◽  
Author(s):  
Aniza Abdulle ◽  
James C. L. Chow
Keyword(s):  
Monte Carlo ◽  
Contrast Enhancement ◽  
Beam Energy ◽  
Photon Beam ◽  
Nanoparticle Concentration ◽  
Photon Beams ◽  
Portal Imaging ◽  
Flattening Filter Free ◽  
Rate Of Increase ◽  
Flattening Filter

Our team evaluated contrast enhancement for portal imaging using Monte Carlo simulation in nanoparticle-enhanced radiotherapy. Dependencies of percentage contrast enhancement on flattening-filter (FF) and flattening-filter-free (FFF) photon beams were determined by varying the nanoparticle material (gold, platinum, iodine, silver, iron oxide), nanoparticle concentration (3–40 mg/mL) and photon beam energy (6 and 10 MV). Phase-space files and energy spectra of the 6 MV FF, 6 MV FFF, 10 MV FF and 10 MV FFF photon beams were generated based on a Varian TrueBeam linear accelerator. We found that gold and platinum nanoparticles (NP) produced the highest contrast enhancement for portal imaging, compared to other NP with lower atomic numbers. The maximum percentage contrast enhancements for the gold and platinum NP were 18.9% and 18.5% with a concentration equal to 40 mg/mL. The contrast enhancement was also found to increase with the nanoparticle concentration. The maximum rate of increase of contrast enhancement for the gold NP was equal to 0.29%/mg/mL. Using the 6 MV photon beams, the maximum contrast enhancements for the gold NP were 79% (FF) and 78% (FFF) higher than those using the 10 MV beams. For the FFF beams, the maximum contrast enhancements for the gold NP were 53.6% (6 MV) and 53.8% (10 MV) higher than those using the FF beams. It is concluded that contrast enhancement for portal imaging can be increased when a higher atomic number of NP, higher nanoparticle concentration, lower photon beam energy and no flattening filter of photon beam are used in nanoparticle-enhanced radiotherapy.

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