SU-E-T-266: New Improved Methods to Read Output Factors for Small Fields

2013 ◽  
Vol 40 (6Part14) ◽  
pp. 265-265
Author(s):  
C Smith ◽  
A Bacala ◽  
S Pella
Keyword(s):  
Small Fields ◽  
Output Factors ◽  
Improved Methods

scholarly journals Field output factors for small fields: A large multicentre study

2021 ◽  
Vol 81 ◽  
pp. 191-196
Author(s):  
S. Dufreneix ◽  
J. Bellec ◽  
S. Josset ◽  
L. Vieillevigne
Keyword(s):  
Multicentre Study ◽  
Small Fields ◽  
Output Factors ◽  
Large Multicentre Study

SU-F-T-572: Small Fields Output Factors Measurement and Correction Factor Determination for Several Active and Passive Detectors

2016 ◽  
Vol 43 (6Part22) ◽  
pp. 3595-3595
Author(s):  
D Sharma ◽  
S Sharma ◽  
R Chowdhary ◽  
S Pilakkal ◽  
S Rashal
Keyword(s):  
Correction Factor ◽  
Small Fields ◽  
Output Factors

scholarly journals OC-0459: Small fields output factors and correction factors determination for a linac with circular cones

2016 ◽  
Vol 119 ◽  
pp. S216
Author(s):  
A. Girardi ◽  
C. Fiandra ◽  
E. Gallio ◽  
F.R. Giglioli ◽  
R. Ragona
Keyword(s):  
Correction Factors ◽  
Small Fields ◽  
Output Factors

scholarly journals Measuring output factors of small fields formed by collimator jaws and multileaf collimator using plastic scintillation detectors

2010 ◽  
Vol 37 (10) ◽  
pp. 5541-5549 ◽  
Author(s):  
David M. Klein ◽  
Ramesh C. Tailor ◽  
Louis Archambault ◽  
Lilie Wang ◽  
Francois Therriault-Proulx ◽  
...  
Keyword(s):  
Scintillation Detectors ◽  
Multileaf Collimator ◽  
Plastic Scintillation ◽  
Small Fields ◽  
Output Factors

scholarly journals PO-0776: Output factors measurements with radiochromic films for small fields on a Cyberknife unit

2013 ◽  
Vol 106 ◽  
pp. S296
Author(s):  
C. Vite ◽  
A.S. Martinotti ◽  
A. Bergantin ◽  
F. Ria ◽  
L.C. Bianchi ◽  
...  
Keyword(s):  
Radiochromic Films ◽  
Small Fields ◽  
Output Factors

scholarly journals Can Gafchromic EBT3 films effectively characterize small fields of 6 MV unflattened photon beams of Cyberknife system?

2018 ◽  
Vol 24 (4) ◽  
pp. 181-187
Author(s):  
Jerrin Amalraj ◽  
Ramasubramanian Velayudham ◽  
Pichandi Anchineyan
Keyword(s):  
Silicon Detectors ◽  
Photon Beams ◽  
Output Factor ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Gamma Analysis ◽  
Small Fields ◽  
Output Factors ◽  
Dose Measurements ◽  
Dose Difference

Abstract Shielded silicon diodes are commonly employed in commissioning of Cyberknife 6 MV photon beams. This study aims to measure output factors, off centered ratio (OCR), percentage depth dose (PDD) of 6 MV photons using shielded and unshielded diodes and to compare with Gafchromic EBT3 film measurements to investigate whether EBT3 could effectively characterize small 6 MV photon beams. Output factors, OCR and PDD were measured with shielded and unshielded silicon detectors in a radiation field analyzer system at reference condition. Water equivalent solid phantom were used while irradiating EBT3 films. From multiuser data, diodes underestimated output factor by 3% for collimator fields ≤ 10 mm, while EBT3 underestimated the output factor by 3.9% for 5 mm collimator. 1D Gamma analysis of OCR between diode and film, results in gamma ≤ 1 for all measured points with 1 mm distance to agreement (DTA) and 1% relative dose difference (DD). Dose at surface is overestimated with diodes compared to EBT3. PDD results were within 2% relative dose values between diode and EBT3 except for 5 mm collimator. Except for small collimator fields of up to 10 mm, results of output factor, OCR, PDD of all detectors used in this study exhibited similar results. Relative dose measurements with Gafchromic EBT3 in this work show that EBT3 films can be used effectively as an independent tool to verify commissioning beam data of small fields only after careful verification of methodology for any systematic errors with appropriate readout procedure.

scholarly journals The influence of small field output factors simulated uncertainties on the calculated dose in VMAT plans for brain metastases: a multicentre study

2021 ◽  
Vol 94 (1119) ◽  
pp. 20201354
Author(s):  
Stefania Clemente ◽  
Maria Daniela Falco ◽  
Elisabetta Cagni ◽  
Cinzia Talamonti ◽  
Mafalda Boccia ◽  
...  
Keyword(s):  
Multicentre Study ◽  
Virtual Machines ◽  
Planning System ◽  
Treatment Planning System ◽  
Delivery Mode ◽  
Small Field ◽  
Dose Volume ◽  
Calculated Dose ◽  
Small Fields ◽  
Output Factors

Objectives: This multicentric study was carried out to investigate the impact of small field output factors (OFs) inaccuracies on the calculated dose in volumetric arctherapy (VMAT) radiosurgery brain plans. Methods: Nine centres, realised the same five VMAT plans with common planning rules and their specific clinical equipment Linac/treatment planning system commissioned with their OFs measured values (OFbaseline). In order to simulate OFs errors, two new OFs sets were generated for each centre by changing only the OFs values of the smallest field sizes (from 3.2 × 3.2 cm2 to 1 × 1 cm2) with well-defined amounts (positive and negative). Consequently, two virtual machines for each centre were recommissioned using the new OFs and the percentage dose differences ΔD (%) between the baseline plans and the same plans recalculated using the incremented (OFup) and decremented (OFdown) values were evaluated. The ΔD (%) were analysed in terms of planning target volume (PTV) coverage and organs at risk (OARs) sparing at selected dose/volume points. Results: The plans recalculated with OFdown sets resulted in higher variation of doses than baseline within 1.6 and 3.4% to PTVs and OARs respectively; while the plans with OFup sets resulted in lower variation within 1.3% to both PTVs and OARs. Our analysis highlights that OFs variations affect calculated dose depending on the algorithm and on the delivery mode (field jaw/MLC‐defined). The Monte Carlo (MC) algorithm resulted significantly more sensitive to OFs variations than all of the other algorithms. Conclusion: The aim of our study was to evaluate how small fields OFs inaccuracies can affect the dose calculation in VMAT brain radiosurgery treatments plans. It was observed that simulated OFs errors, return dosimetric calculation accuracies within the 3% between concurrent plans analysed in terms of percentage dose differences at selected dose/volume points of the PTV coverage and OARs sparing. Advances in knowledge: First multicentre study involving different Planning/Linacs about undetectable errors in commissioning output factor for small fields.

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