A dual two dimensional electronic portal imaging device transit dosimetry model based on an empirical quadratic formalism

Tan, Yun Yi; Metwaly, Mohamed; Glegg, M.; Baggarley, Shaun; Elliott, Alex

doi:10.1259/bjr.20140645

Cited by 3 publications

(5 citation statements)

References 43 publications

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“…In the same vein, Tan et al . stated that the TPS cannot accurately calculate the dose in shoulder and penumbra regions [13]. However, other researchers, evaluating the accuracy of dose calculation by different TPSs, have confirmed the inaccuracy of these systems [27], the various calculation algorithms have different levels of inaccuracy [28].…”

Section: Discussionmentioning

confidence: 99%

“…Elekta with the collaboration of Netherlands Cancer Institute has recently introduced a solution (iViewDose, Elekta AB, Stockholm, Sweden) that used a convolution model for transmission EPID dosimetry [36]. However, the empirical methods are more practical for clinical implementation, compared with the convolution model [13,37,38]. In the present study, it was attempted to verify the a-Si EPID for dosimetry purposes using an empirical method.…”

Section: Discussionmentioning

confidence: 99%

“…One of the main differences of the empirical method employed in this research with those presented in other studies is that the calculation of dose does not limit to one or two situations [13,39] and that our method can calculate the 2D dose map at any SID.…”

Section: Discussionmentioning

confidence: 99%

“…The transit dosimetry is the measurement of the dose behind the patient/phantom at the detector plane, and the non-transit dosimetry, is the determination of dose without an attenuating medium between the linear accelerator’s target and EPID [1]. Given the incapability of the non-transited model in detecting all errors during the treatment, the transit model is preferred over the non-transit one [13]. In both models, EPID dosimetry can be performed by either forward or backward approaches [14].…”

Section: Introductionmentioning

confidence: 99%

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An Empirical Transmitted EPID Dosimetry Method using a Back- Projection Algorithm

et al. 2019

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Background:The present study aimed to introduce a rapid transmission dosimetry through an electronic portal-imaging device (EPID) to achieve two-dimensional (2D) dose distribution for homogenous environments. Material and Methods: In this Phantom study, first, the EPID calibration curve and correction coefficients for field size were obtained from EPID and ionization chamber. Second, the EPID off-axis pixel response was measured, and the grey-scale image of the EPID was converted into portal dose image using the calibration curve. Next, the scattering contribution was calculated to obtain the primary dose. Then, by means of a verified back-projection algorithm and the Scatter-to-Primary dose ratio, a 2D dose distribution at the mid-plane was obtained. Results: The results obtained from comparing the transmitted EPID dosimetry to the calculated dose, using commercial treatment planning system with gamma function while there is 3% dose difference and 3mm distance to agreement criteria, were in a good agreement. In addition, the pass rates of γ < 1 was 94.89% for the homogeneous volumes. Conclusion:Based on the results, the method proposed can be used in EPID dosimetry.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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An Empirical Transmitted EPID Dosimetry Method using a Back- Projection Algorithm

et al. 2019

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“…To ensure the consistency of the MLC and beam angle, an EPID detector is permanently attached inside the Halcyon. EPID images can be extracted to provide dose distribution information; as a dosimetry method for verification before and during therapy [5][6][7][8][9][10][11][12][13][14]. One type of dosimetry by EPID is non-transit dosimetry, which can predict the dose inside the patient for pre-treatment verification by measuring doses at a certain height without an attenuator.…”

Section: Introductionmentioning

confidence: 99%

Comparison of deep learning models for building two-dimensional non-transit EPID Dosimetry on Varian Halcyon

Ramadhan,

Wibowo,

Prajitno

et al. 2024

Rep Pract Oncol Radiother.

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Background This study compared the effectiveness of five deep learning models in constructing non-transit dosimetry with an a-Si electronic portal imaging device (EPID) on Varian Halcyon. Deep learning model is increasingly used to support prediction and decision-making in several fields including oncology and radiotherapy. Materials and methods Forty-seven unique plans of data obtained from breast cancer patients were calculated using Eclipse treatment planning system (TPS) and extracted from DICOM format as the ground truth. Varian Halcyon was then used to irradiate the a-Si 1200 EPID detector without an attenuator. The EPID and TPS images were augmented and divided randomly into two groups of equal sizes to distinguish the validation and training–test data. Five different deep learning models were then created and validated using a gamma index of 3%/3 mm. Results Four models successfully improved the similarity of the EPID images and the TPS-generated planned dose images. Meanwhile, the mismatch of the constituent components and number of parameters could cause the models to produce wrong results. The average gamma pass rates were 90.07 ± 4.96% for A-model, 77.42 ± 7.18% for B-model, 79.60 ± 6.56% for C-model, 80.21 ± 5.88% for D-model, and 80.47 ± 5.98% for E-model. Conclusion The deep learning model is proven to run fast and can increase the similarity of EPID images with TPS images to build non-transit dosimetry. However, more cases are needed to validate this model before being used in clinical activities.

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Dosimetric verification of IMRT and 3D conformal treatment delivery using EPID

Nasseri

Bahreyni

Momennezhad

et al. 2022

Applied Radiation and Isotopes

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A dual two dimensional electronic portal imaging device transit dosimetry model based on an empirical quadratic formalism

Abstract: The described model is practical, generic and flexible to encourage widespread implementation of EPID dosimetry for the improvement of patients' safety in radiotherapy.

Cited by 3 publications

References 43 publications

An Empirical Transmitted EPID Dosimetry Method using a Back- Projection Algorithm

An Empirical Transmitted EPID Dosimetry Method using a Back- Projection Algorithm

Comparison of deep learning models for building two-dimensional non-transit EPID Dosimetry on Varian Halcyon

Dosimetric verification of IMRT and 3D conformal treatment delivery using EPID

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