Effects of Siemens TT-D carbon fiber table top on beam attenuation, and build up region of 6 MV photon beam

Sheykhoo, Asma; Abdollahi, Sara; Yazdi, Mohammad Hadi Hadizadeh; Ghorbani, Mahdi; Mohammadi, Mohammad

doi:10.1016/j.rpor.2016.09.001

Cited by 7 publications

(7 citation statements)

References 36 publications

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“…For example, Seppälä et al 4 measured that the increased percentage of relative skin dose with involvement of eight different CFCs varied from 73.86 to 180.11% under the context of field size 10 cm × 10 cm for 6 MV photon, the best ones were Varian grid insert and Qfix kVue DoseMax which were both grid-based, those of most solid CFCs were similar to our data. For some counterparts, the surface dose effect in our work showed apparent superiority, for instance, David et al 24 measured that the increased skin dose with involvement of the iBEAM evo CFC was 513%, and Sheykhoo et al 25 reported their data of 514.53% increased skin dose with the 550 TXT CFC under the same context of 10 cm × 10 cm for 6 MV photon, while that of uRT- linac 506c was 213.25%. The effect depends on multiple factors including couch design and structure, material, photon beam quality, and field size as well.…”

Section: Discussionmentioning

confidence: 52%

Radiation dosimetry effect evaluation of a carbon fiber couch on novel uRT-linac 506c accelerator

Jiang

Zhi-min

Wei

et al. 2021

Sci Rep

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Recently, a diagnostic helical CT is integrated into a linear accelerator, called uRT-linac 506c, whose CT scanning dataset can be directly used to do simulation. This novel structure provides a possibility for online adaptive radiotherapy. For adaptive radiotherapy, the carbon fiber couch is an essential external device for supporting and positioning patients. And the effect on dose attenuation and distribution caused by a couch is inevitable and vital for precise treatment. In this research, the couch equipped with uRT-linac 506c was evaluated on the radiation dosimetry effect. The treatment couch equipped on the uRT-linac 506c accelerator was evaluated, and its effect on the attenuation, surface dose and dose buildup were measured for different phantom positions (offset = 0 cm, offset = + 10 cm and offset = − 10 cm, respectively) and different gantry angles. Since uRT-linac 506c is exclusively capable to provide diagnostic CT scanning data with real relative electron density (RED), this CT scanning data of the couch can be used directly in uRT-TPS to design plans. This scanned couch dataset was designated as the model A. The model B was a dummy structure of a treatment couch inserted with artificially preset RED. The dose calculation accuracy of these two models was compared using PB, CC, and MC on uRT-TPS. With the effect of carbon fiber couch, the surface dose was increased at least 97.94% for 25 × 25 cm2 field and 188.83% for 10 × 10 cm2 field, compared with those without. At different phantom positions (offset = 0, + 10, − 10 cm), the attenuation for 6 MV photon beam at gantry angle 180° were 4.4%, 4.4%, and 4.3%, respectively, and varied with changes of gantry angle. There do exists dose deviation between measurement and TPS calculation with the involvement of treatment couch, among the three algorithms, MC presented the least deviation, and the model A made less and steadier deviation than the model B, showing promising superiority. The attenuation, surface dose, and buildup effects of the carbon fiber couch in this study were measured similarly to most counterparts. The dose deviation calculated based on the couch dataset scanned by the diagnostic helical CT was smaller than those based on a dummy couch. This result suggests that an accelerator equipped with a diagnostic CT, which can help reduce the dose deviation of the carbon fiber couch, is a promising platform for online adaptive radiotherapy.

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Section: Discussionmentioning

confidence: 52%

Radiation dosimetry effect evaluation of a carbon fiber couch on novel uRT-linac 506c accelerator

Jiang

Zhi-min

Wei

et al. 2021

Sci Rep

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“…There are several reports evaluating the validation of treatment couches modelling in TPS. 8,9,[17][18][19] In a study by Njeh et al, 8 the BrainLAB couch top has been modelled in Philips Pinnacle and BrainLAB iPlan RT Dose TPSs. They demonstrated an excellent agreement (1% for all gantry angles measured except for 120 o , which was 1•8%) between the measured dose and Pinnacle TPS computed dose using 6 MV photon beams.…”

Section: Discussionmentioning

confidence: 99%

Dosimetric effect of modelling non-homogeneous LINAC couch using cone-beam computed tomography on quality assurance (QA) results

Banaei

Bakhshandeh²,

Golrokh-Nodehi³

2022

J Radiother Pract

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Aim: To evaluate the dosimetric effect of modelling a non-homogeneous couch on patients’ quality assurance (QA) gamma pass rates for intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) techniques. Materials and Methods: A non-homogeneous treatment couch (TxT 550 TTM, CIVCO, USA) was imaged using the LINAC mounted cone-beam computer tomography (CBCT) system. Modelling this couch in different situations, including incomplete (homogeneous model), correct model and not defined situations in the treatment planning system (TPS), was performed based on the geometrical and material densities data extracted from the CBCT images. Calculated gamma pass rates between TPS dose calculations and the measurements in a phantom for different couch models were obtained and compared at two gamma criteria (2%-2 mm and 3%-3 mm). Results: Comparing TPS calculations for the correct modelled couch and the measurements showed high gamma pass rates for both the IMRT and VMAT techniques (96·5 ± 0·9%, 99·2 ± 0·5% for IMRT in 2%-2 mm and 3%-3 mm criteria; 97·5 ± 0·8%, 99·4 ± 0·5% for VMAT). The overall gamma pass rate of the IMRT plan QAs was reduced by about 2% and 3% on average for incomplete and no couch modelling, respectively. These reductions for VMAT techniques were 2·5% and 4·3%, respectively. Conclusions: Non-homogeneous couches have different parts with different attenuations, which can be correctly defined using LINAC CBCT. Modelling of treatment couch has a significant effect on patient QA results for VMAT and IMRT plans, especially in radiation fields/subfield transmitting from the couch. We suggest using LINAC CBCTs as an appropriate device for couch modelling in modulated radiotherapy techniques.

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“…The TC is made up of two thin carbon fiber plates that are about 2.0 mm to 4.0 mm thick and sandwich air-equivalent polymeric foam between them. And it contains a low attenuation property, high mechanical strength, rigidity, low density and lightweight in order to use in radiotherapy treatments (Olch et al, 2014;Sheykhoo et al, 2017). The immobilization devices such as Vac lok Cushions (VLC), All in One positioning system (AIO-PS) and thermoplastic mask are employed to ensure patient positioning during the course of the treatment.…”

Section: A Study To Analyze Impact Of Treatment Couch and Immobilizat...mentioning

confidence: 99%

A Study to Analyze Impact of Treatment Couch and Immobilization Devices on Surface Dose for Megavoltage Photon Beams

et al. 2023

Asian Pac J Cancer Prev

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Purpose/Objective: The purpose of this study is to investigate the effect of treatment couch and immobilization devices on surface dose for megavoltage photon beams. Material/Methods: Percentage surface dose (PSD) measurement was carried out in Elekta Synergy™ Linear accelerator using PTW Markus® Parallel plate ionization chamber of volume 0.05cm3 with water equivalent RW3 Slab phantom (PTW, Germany). The measurement depth was considered at 0.07mm. The reference PSD was measured at 0° gantry angle with 10×10cm 2 , 20×20cm 2 and 30×30cm 2 field sizes and 100cm SSD for 4MV, 6MV and 15MV photon beams. For comparison, PSD measurement was carried out at 180° gantry angle inclusion of treatment couch (TC), All in One positioning system (AIO – PS) and Vac lok Cushions (VLC). Results: Beam angle at 0°, for field sizes 10×10cm2, 20×20cm2 and 30×30cm 2 , the PSD was observed as 30.9%, 40.5%, 48.7% for 4MV; 23.7%, 33.8%, 42.2% for 6MV; and 17.0%, 29.6%, 38.6% for 15MV respectively. Beam angle at 180° with TC, an increase in PSD by maximum of 65.0% for 4MV, 64.9% for 6MV and 55.9% for 15MV as compared to 0° angle. The PSD increased when beam angle was 180° with TC and AIO – PS were 65.0% for 4MV, 67.4% for 6MV, and 60.9% for 15MV than 0° angle. Similarly, increased PSD for beam angle at 180° with TC and VLC were 66.8% for 4MV, 66.8% for 6MV and 61.3% for 15MV as compared to 0° angle. Conclusion: For all three-photon energies, at 180° gantry angle, the PSD increased significantly in case of TC, VLC, and AIO – PS for all the field sizes as compared to gantry angle at 0°. It is necessary to consider TC, AIO – PS and VLC during dose calculation to ensure accuracy of patient treatment delivery.

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Effects of Siemens TT-D carbon fiber table top on beam attenuation, and build up region of 6 MV photon beam

Cited by 7 publications

References 36 publications

Radiation dosimetry effect evaluation of a carbon fiber couch on novel uRT-linac 506c accelerator

Radiation dosimetry effect evaluation of a carbon fiber couch on novel uRT-linac 506c accelerator

Dosimetric effect of modelling non-homogeneous LINAC couch using cone-beam computed tomography on quality assurance (QA) results

A Study to Analyze Impact of Treatment Couch and Immobilization Devices on Surface Dose for Megavoltage Photon Beams

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