Determination of small field output factors in 6 and 10 MV flattening filter free photon beams using various detectors

Masanga, W; Tangboonduangjit, P; Khamfongkhruea, Chirasak; Tannanonta, Chirapha

doi:10.1088/1742-6596/694/1/012027

Cited by 11 publications

(8 citation statements)

References 12 publications

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“…The OF differences between their study and our study are within ±0.53%. Masanga et al reported OFs for field sizes from 0.6 × 0.6 cm 2 to 4 × 4 cm 2 measured using the Edge detector [20]. The OF differences from our study are within ±0.55% except for a field size of 1 × 1 cm 2 (−1.22% difference).…”

Section: Measurementssupporting

confidence: 54%

Commissioning of the TrueBeam STx 6 MV FFF Beam in the RayStation Treatment Planning System for SRS and SBRT Treatments

Lee¹,

Kim²

2021

IJMPCERO

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Purpose: The purpose of this study is to provide technical information on commissioning the TrueBeam STx 6 MV flattening-filter free (FFF) beam in the RayStation treatment planning system (TPS) for stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) treatments. Methods: For beam modeling, percent depth dose curves, profiles and output factors for jaw-collimated fields and stereotactic cones as well as X-jaws transmission were measured. For multi-leaf collimator (MLC) modeling, MLC model parameters such as offset, gain, curvature, leaf tip width, tongue and groove and transmission were determined and output factors for MLC-collimated fields were measured. Absolute dose calibration was also performed. For beam model and MLC model validation, the American Association of Physicists in Medicine Task Group-119 plans, clinical SRS and SBRT plans and end-to-end testing were performed. Results: Beam characteristics of the 6 MV FFF beam agreed well with those in the literature. Validation results showed that our beam model and MLC model were acceptable for SRS and SBRT treatments. Conclusions: The technical information and dosimetric data provided in this study will be a useful reference for other clinics/institutions which will commission the same machine energy in the RayStation TPS.

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Section: Measurementssupporting

confidence: 54%

Commissioning of the TrueBeam STx 6 MV FFF Beam in the RayStation Treatment Planning System for SRS and SBRT Treatments

Lee¹,

Kim²

2021

IJMPCERO

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“…PDDs were acquired using a PTW (Freiburg, Germany) Semiflex 3D ionization chamber for fields ≥ 4 cm 2 and a PTW microdiamond 19 in the edge-on orientation 20 and a microdiamond in the edge-on orientation for fields < 4 cm 2 , with the detector sitting at 10 cm depth and 90 cm SSD in a water tank. Readings were referenced back to that of 10 × 10 cm 2 through daisy-chaining 21 to calculate output factors.…”

Section: A1 | Pdds and Profiles Of Standard Square Fieldsmentioning

confidence: 99%

Validation of the preconfigured Varian Ethos Acuros XB Beam Model for treatment planning dose calculations: A dosimetric study

Byrne

Archibald-Heeren

et al. 2020

J Applied Clin Med Phys

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Varian (Palo Alto, California, United States) recently released an online adaptation treatment platform, Ethos, which has introduced a new Dose Preview and Automated Plan Generation module despite sharing identical beam data with the existing Halcyon linac. The module incorporates a preconfigured beam model and the Acuros XB algorithm (Ethos AXB model) to generate final dose calculations from an initial fluence optimization. In this study, we comprehensively validated the accuracy of the Ethos AXB model by comparing it against the Halcyon AXB model, the Halcyon Anisotropic Analytical Algorithm (AAA) model, and measurements acquired on an Ethos linac. Results indicated that the Ethos AXB model demonstrated a comparable if not superior dosimetric accuracy to the Halcyon AXB model in basic and complex calculations, and at the same time its dosimetric accuracy in modulated and heterogeneous plans was better than that of the Halcyon AAA model. Despite the fact that the same algorithm was utilized, the Ethos AXB model and the Halcyon AXB model still exhibited variations across a range of tests, although these variations were predominantly insignificant in the clinical environment. The accuracy of the Ethos AXB model has been successfully verified in this study and is considered appropriate for the current clinical scope. On the basis of this study, clinical physicists can perform a data validation instead of a full data commissioning when implementing the Ethos system, thereby adopting a more efficient approach for Ethos installation.

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“…The increasing output as a function of field size increment is ascribed to back scattered radiation and collimator scatters, which added to primary beam [11]. Such exponential trend of output versus field size has been obtained by Masanga [12]. While the correlation between the output in Gy/Mu versus SSD s at field size of 10×10 cm revealed that: the system output in Gy/Mu has been decreases in logarithmic equation form that could be fitted to = -1.91×ln ( ) + 9.846, where ' ' refers to SSD in cm and ' ' refers to output in Gy/Mu which is due to decreased radiation intensity as shown in Figure (11).…”

Section: Resultsmentioning

confidence: 86%

Instrumental Quality Control of Therapeutic Linear Accelerator Performance

Omer¹

2017

AJPA

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Abstract:The objective of the article was to assess therapeutic linear accelerator performance. Material & method used were quality control tools, direct measurement & theoretical calculation methods. The analysis of results showed that: shift of machine isocenter was 1 mm then increases up to 2 mm through the gantry angles 0 to 300° and 300 to 360 respectively. The diaphragm rotation isocenter clock & anti-clock wise was 1mm. the light and radiation fields showed concise matching up to 9×9 cm, then for 10×10, 14×14 and 16×16 cm there were incongruence by 0.25, 0.3 and 0.41 cm respectively. The increment of the field sizes (2×2, 4×4 -20×20) cm following SSD increment fitted with the inverse square law significantly (R 2 = 1). The theoretical (calculation method) field size was greater than the measured (practical) field size relative to SSD by 0.2 cm. The system output in Gy/Mu increases significantly (R 2 = 0.9) as the field size increases in logarithmic equation; while it decreases as SSD increases. The measured output on phantom surface was greater (0.8Gy/MU) than that calculated theoretically which was (0.5 Gy/MU). A significant (R 2 = 0.8) reduction in output reading following the increment of temperature for Linac 10 MV and 6 MV respectively, while the pressure lead to significant (0.6) increment of system output reading. TLD showed narrow penumbra extension as 0.32 and 0.2 cm for lianc 6MV and 10MV respectively compared with 0.5 and 0.3 cm at maximum depth dose when obtained from dose histogram.

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Determination of small field output factors in 6 and 10 MV flattening filter free photon beams using various detectors

Cited by 11 publications

References 12 publications

Commissioning of the TrueBeam STx 6 MV FFF Beam in the RayStation Treatment Planning System for SRS and SBRT Treatments

Commissioning of the TrueBeam STx 6 MV FFF Beam in the RayStation Treatment Planning System for SRS and SBRT Treatments

Validation of the preconfigured Varian Ethos Acuros XB Beam Model for treatment planning dose calculations: A dosimetric study

Instrumental Quality Control of Therapeutic Linear Accelerator Performance

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